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Sample records for hubble orion nebula

  1. Hubble Space Telescope observations of Orion Nebula, Helix Nebula, and NGC 6822

    Science.gov (United States)

    Spitzer, Lyman; Fitzpatrick, Ed

    1999-01-01

    This grant covered the major part of the work of the Principal Investigator and his collaborators as a Guaranteed Time Observer on the Hubble Space Telescope. The work done naturally divided itself into two portions the first being study of nebular objects and the second investigation of the interstellar medium between stars. The latter investigation was pursued through a contract with Princeton University, with Professor Lyman Spitzer as the supervising astronomer, assisted by Dr. Ed Fitzpatrick. Following the abrupt death of Professor Spitzer, his responsibilities were shifted to Dr. Fitzpatrick. When Dr. Fitzpatrick relocated to Villanova University the concluding work on that portion of this grant was concluded under a direct service arrangement. This program has been highly successful and the resulting publications in scientific journals are listed below. To the scientist, this is the bottom line, so that I shall simply try to describe the general nature of what was accomplished. There were three nebular programs conducted, one on the Orion Nebula, the second on the Helix Nebula, and the third on NGC 6822. The largest program was that on the Orion Nebula. This involved both HST observations and supporting groundbased observations obtained with a variety of instruments, including the Coude Feed Telescope at the Kitt Peak National observatory in Arizona, the Cerro Tololo observatory in Chile, and the Keck Observatory on Mauna Kea, Hawaii. Moreover, considerable theoretical modeling was done and all of the data analysis was performed at the Rice University in Houston, except for the PI's period of sabbatical leave (6-96 through 7-97) when he was based at the Max Planck Institute for Astronomy in Heidelberg, Germany. The Orion Nebula program was the most productive part, resulting in numerous papers, but more important in the discovery of a new class of objects, for which we coined the name "proplyds". The proplyds are protoplanetary disks surrounding very young

  2. The Hubble Space Telescope Treasury Program on the Orion Nebula Cluster

    CERN Document Server

    Robberto, M; Bergeron, E; Kozhurina-Platais, V; Makidon, R B; McCullough, P R; McMaster, M; Panagia, N; Reid, I N; Levay, Z; Frattare, L; Da Rio, N; Andersen, M; O'Dell, C R; Stassun, K G; Simon, M; Feigelson, E D; Stauffer, J R; Meyer, M; Reggiani, M; Krist, J; Manara, C F; Romaniello, M; Hillenbrand, L A; Ricci, L; Palla, F; Najita, J R; Ananna, T T; Scandariato, G; Smith, K

    2013-01-01

    The Hubble Space Telescope (HST) Treasury Program on the Orion Nebula Cluster has used 104 orbits of HST time to image the Great Orion Nebula region with the Advanced Camera for Surveys (ACS), the Wide-Field/Planetary Camera 2 (WFPC2) and the Near Infrared Camera and Multi Object Spectrograph (NICMOS) instruments in 11 filters ranging from the U-band to the H-band equivalent of HST. The program has been intended to perform the definitive study of the stellar component of the ONC at visible wavelengths, addressing key questions like the cluster IMF, age spread, mass accretion, binarity and cirumstellar disk evolution. The scanning pattern allowed to cover a contiguous field of approximately 600 square arcminutes with both ACS and WFPC2, with a typical exposure time of approximately 11 minutes per ACS filter, corresponding to a point source depth AB(F435W) = 25.8 and AB(F775W)=25.2 with 0.2 magnitudes of photometric error. We describe the observations, data reduction and data products, including images, source ...

  3. THE HUBBLE SPACE TELESCOPE TREASURY PROGRAM ON THE ORION NEBULA CLUSTER {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Robberto, M.; Soderblom, D. R.; Bergeron, E.; Kozhurina-Platais, V.; Makidon, R. B.; McCullough, P. R.; McMaster, M.; Panagia, N.; Reid, I. N.; Levay, Z.; Frattare, L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Da Rio, N.; Andersen, M. [European Space Agency, Keplerlaan 1, 2200-AG Noordwijk (Netherlands); O' Dell, C. R.; Stassun, K. G. [Department of Physics and Astronomy, Vanderbilt University, 6301 Stevenson Center, Nashville, TN 37235 (United States); Simon, M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794 (United States); Feigelson, E. D. [Department of Astronomy and Astrophysics, Pennsylvania State University, 518 Davey Lab, University Park, PA 16802 (United States); Stauffer, J. R. [Spitzer Science Center, California Institute of Technology 314-6, Pasadena, CA 91125 (United States); Meyer, M.; Reggiani, M., E-mail: robberto@stsci.edu [ETH Zuerich, Institut fuer Astronomie, Wolfgang-Pauli-Strasse 27, CH-8093 Zuerich (Switzerland); and others

    2013-07-01

    The Hubble Space Telescope (HST) Treasury Program on the Orion Nebula Cluster (ONC) has used 104 orbits of HST time to image the Great Orion Nebula region with the Advanced Camera for Surveys (ACS), the Wide-Field/Planetary Camera 2 (WFPC2), and the Near-Infrared Camera and Multi-Object Spectrograph (NICMOS) instrument in 11 filters ranging from the U band to the H band equivalent of HST. The program has been intended to perform the definitive study of the stellar component of the ONC at visible wavelengths, addressing key questions like the cluster initial mass function, age spread, mass accretion, binarity, and cirumstellar disk evolution. The scanning pattern allowed us to cover a contiguous field of approximately 600 arcmin{sup 2} with both ACS and WFPC2, with a typical exposure time of approximately 11 minutes per ACS filter, corresponding to a point source depth AB(F435W) = 25.8 and AB(F775W) = 25.2 with 0.2 mag of photometric error. We describe the observations, data reduction, and data products, including images, source catalogs, and tools for quick look preview. In particular, we provide ACS photometry for 3399 stars, most of them detected at multiple epochs; WFPC2 photometry for 1643 stars, 1021 of them detected in the U band; and NICMOS JH photometry for 2116 stars. We summarize the early science results that have been presented in a number of papers. The final set of images and the photometric catalogs are publicly available through the archive as High Level Science Products at the STScI Multimission Archive hosted by the Space Telescope Science Institute.

  4. The Hubble Space Telescope/Advanced Camera for Surveys Atlas of Protoplanetary Disks in the Great Orion Nebula

    Science.gov (United States)

    Ricci, L.; Robberto, M.; Soderblom, D. R.

    2008-11-01

    We present the atlas of protoplanetary disks in the Orion Nebula based on the Wide Field Channel of the Advanced Camera for Surveys (ACS/WFC) images obtained for the Hubble Space Telescope (HST) Treasury Program on the Orion Nebula Cluster. The observations have been carried out in five photometric filters nearly equivalent to the standard B, V, Hα, I, and z passbands. Our master catalog lists 178 externally ionized protoplanetary disks (proplyds), 28 disks seen only in absorption against the bright nebular background (silhouette disks), eight disks seen only as dark lanes at the midplane of extended polar emission (bipolar nebulae or reflection nebulae), and five sources showing jet emission with no evidence of either external ionized gas emission or dark silhouette disks. Many of these disks are associated with jets seen in Hα and circumstellar material detected through reflection emission in our broadband filters; approximately two-thirds have identified counterparts in X-rays. A total of 47 objects (29 proplyds, seven silhouette disks, six bipolar nebulae, five jets with no evidence of proplyd emission or silhouette disk) are new detections with HST. We include in our list four objects previously reported as circumstellar disks, which have not been detected in our HST/ACS images either because they are hidden by the bleeding trails of a nearby saturated bright star or because of their location out of the HST/ACS Treasury Program field. The other 31 sources previously reported as extended objects do not harbor a stellar source in our HST/ACS images. We also report on the detection of 16 red, elongated sources. Their location at the edges of the field, far from the Trapezium cluster core (gsim10'), suggests that these are probably background galaxies observed through low-extinction regions of the Orion Molecular Cloud (OMC-1). Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is

  5. High Velocity Features in the Orion Nebula

    CERN Document Server

    O'Dell, C R

    2008-01-01

    We have used widely spaced in time Hubble Space Telescope images to determine tangential velocities of features associated with outflows from young stars. These observations were supplemented by groundbased telescope spectroscopy and from the resultant radial velocities, space velocities were determined for many outflows. Numerous new moving features were found and grouped into known and newly assigned Herbig Haro objects. It was found that stellar outflow is highly discontinuous, as frequently is the case, with long-term gaps of a few hundred years and that these outflow periods are marked by staccato bursts over periods of about ten years. Although this has been observed in other regions, the Orion Nebula Cluster presents the richest display of this property. Most of the large scale Herbig Haro objects in the brightest part of the Orion Nebula appear to originate from a small region northeast of the strong Orion-S radio and infrared sources. With the possible exception of HH 203, we are not able to identify...

  6. Monitoring the Orion Nebula Cluster

    Science.gov (United States)

    Reipurth, Bo

    The VYSOS (Variable Young Stars Optical Survey) project has at its disposal five small telescopes: a 5-inch and a 20-inch robotic optical imaging telescope in Hawaii funded by the NSF, and a 6-inch robotic optical imaging telescope, a 32-inch robotic infrared imaging telescope, and a 60-inch optical spectroscopic telescope in Chile, funded and operated from Germany. Through an agreement between the leaders of the two sites (B. Reipurth and R. Chini), it has been decided to devote a significant fraction of time on these facilities to a large Key Project, conducting a massive monitoring survey of the Orion Nebula Cluster. The vast data streams are being reduced through automated customized pipelines. The applicant seeks funding to employ a postdoc and an undergraduate assistant to work at the University of Hawaii and collaborate on the analysis of the data. Virtually all young stars are variable, with a wide range of amplitudes and characteristic timescales. This is mainly due to accretion shocks as material from circumstellar disks fall onto the stars along magnetic funnel flows, but also giant star spots, magnetic flares, occultations by orbiting dust condensations, and eclipses by companions can modulate the light from the nascent star. It is increasingly recognized that the rather static view of pre-main sequence evolution that has prevailed for many years is misleading, and that time-dependent phenomena may hold the key to an understanding of the way young stars grow and their circumstellar environments evolve. The VYSOS project is designed to bring sophisticated modern techniques to bear on the long neglected problem of variability in young solar type stars. To interpret the observations they will be compared to sophisticated MHD models of circumstellar disks around young stars. The Orion Nebula Cluster is the nearest rich region of star formation, and numerous, albeit heterogeneous, studies exist of the cluster members. The present study will provide the first

  7. HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA (color)

    Science.gov (United States)

    2002-01-01

    A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This colorful photo shows a ground-based image of the entire Crab Nebula, the remnant of a supernova explosion witnessed over 900 years ago. The nebula, which is 10 light-years across, is located 7,000 light-years away in the constellation Taurus. The green, yellow and red filaments concentrated toward the edges of the nebula are remnants of the star that were ejected into space by the explosion. At the center of the Crab Nebula lies the Crab Pulsar -- the collapsed core of the exploded star. The Crab Pulsar is a rapidly rotating neutron star -- an object only about six miles across, but containing more mass than our Sun. As it rotates at a rate of 30 times per second the Crab Pulsar's powerful magnetic field sweeps around, accelerating particles, and whipping them out into the nebula at speeds close to that of light. The blue glow in the inner part of the nebula -- light emitted by energetic electrons as they spiral through the Crab's magnetic field -- is powered by the Crab Pulsar. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

  8. HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA

    Science.gov (United States)

    2002-01-01

    A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This picture shows a Hubble Space Telescope image of the inner parts of the Crab. The pulsar itself is visible as the left of the pair of stars near the center of the frame. Surrounding the pulsar is a complex of sharp knots and wisp-like features. This image is one of a sequence of Hubble images taken over the course of several months. This sequence shows that the inner part of the Crab Nebula is far more dynamic than previously understood. The Crab literally 'changes it stripes' every few days as these wisps stream away from the pulsar at half the speed of light. The Hubble Space Telescope photo was taken Nov. 5, 1995 by the Wide Field and Planetary Camera 2 at a wavelength of around 550 nanometers, in the middle of the visible part of the electromagnetic spectrum. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

  9. The Orion Nebula: The Jewel in the Sword

    Science.gov (United States)

    2001-01-01

    -Res - JPEG: 2273 x 2784 pix - 976k] Caption : PR Photo 03d/01 shows a small section of the observational data (in one infrared spectral band only, here reproduced in B/W) on which PR Photo 03a/01 is based. The field is centred on one of the famous Orion silhouette disks (Orion 114-426) (it is located approximately halfway between the centre and the right edge of PR Photo 03c/01 ). The dusty disk itself is seen edge-on as a dark streak against the background emission of the Orion Nebula, while the bright fuzzy patches on either side betray the presence of the embedded parent star that illuminates tenuous collections of dust above its north and south poles to create these small reflection nebulae. Recent HST studies suggest that the very young Orion 114-426 disk - that is thirty times bigger than our present-day Solar System - may already be showing signs of forming its own proto-planetary system. Technical information about this photo is available below. It is even possible to see disks of dust and gas surrounding a few of the young stars, as silhouettes in projection against the bright background of the nebula. Many of these disks are very small and usually only seen on images obtained with the Hubble Space Telescope (HST) [2]. However, under the best seeing conditions on Paranal, the sharpness of VLT images at infrared wavelengths approaches that of the HST in this spectral band, revealing some of these disks, as shown in PR Photo 03d/01 . Indeed, the theoretical image sharpness of the 8.2-m VLT is more than three times better than that of the 2.4-m HST. Thus, the VLT will soon yield images of small regions with even higher resolution by means of the High-Resolution Near-Infrared Camera (CONICA) and the Nasmyth Adaptive Optics System (NAOS) that will compensate the smearing effect introduced by the turbulence in the atmosphere. Later on, extremely sharp images will be obtained when all four VLT telescopes are combined to form the Very Large Telescope Interferometer (VLTI

  10. Mining the HST Survey of the Orion Nebula Cluster

    Science.gov (United States)

    Robberto, Massimo; Da Rio, Nicola

    2013-07-01

    The Hubble Space Telescope (HST) Treasury Program on the Orion Nebula Cluster has used 104 orbits of HST time to image the Great Orion Nebula region with the Advanced Camera for Surveys (ACS), the Wide-Field/Planetary Camera 2 (WFPC2) and the Near Infrared Camera and Multi Object Spectrograph (NICMOS) instrument in 11 filters ranging from the U-band to the H-band equivalent of HST. The program has been intended to perform the definitive study of the stellar component of the ONC at visible wavelengths, addressing key questions like the cluster IMF, age spread, mass accretion, binarity and circumstellar disk evolution. The scanning pattern allowed to cover a contiguous field of approximately 600 square arcmin with both ACS and WFPC2 reaching a photometric depth AB(F435W)=25.8 and AB(F775W)=25.2 with 0.2 magnitudes of photometric error. The paper Robberto et al. (2013, ApJSS 207, 10) describes the observations, data reduction and data products, including images, source catalogs and tools for quick look preview. In particular, source catalogs provide ACS photometry for 3399 stars, most of them detected at multiple epochs, WFPC2 photometry for 1643 stars, 1021 of them detected in the U-band, and NICMOS JH photometry for 2117 stars. The paper also summarize the early science results already published. The final set of images and the photometric catalogs are now publicly available through the archive as High Level Science Products at the STScI Multimission Archive hosted by the Space Telescope Science Institute. Here is a graphic description of how to access the data.

  11. Visual Binaries in the Orion Nebula Cluster

    CERN Document Server

    Reipurth, Bo; Connelley, Michael S; Bally, John

    2007-01-01

    We have carried out a major survey for visual binaries towards the Orion Nebula Cluster using HST images obtained with an H-alpha filter. Among 781 likely ONC members more than 60" from theta-1 Ori C, we find 78 multiple systems (75 binaries and 3 triples), of which 55 are new discoveries, in the range from 0.1" to 1.5". About 9 binaries are likely line-of-sight associations. We find a binary fraction of 8.8%+-1.1% within the limited separation range from 67.5 to 675 AU. The field binary fraction in the same range is a factor 1.5 higher. Within the range 150 AU to 675 AU we find that T Tauri associations have a factor 2.2 more binaries than the ONC. The binary separation distribution function of the ONC shows unusual structure, with a sudden steep decrease in the number of binaries as the separation increases beyond 0.5", corresponding to 225 AU. We have measured the ratio of binaries wider than 0.5" to binaries closer than 0.5" as a function of distance from the Trapezium, and find that this ratio is signifi...

  12. The Orion Nebula: Still Full of Surprises

    Science.gov (United States)

    2011-01-01

    This ethereal-looking image of the Orion Nebula was captured using the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory, Chile. This nebula is much more than just a pretty face, offering astronomers a close-up view of a massive star-forming region to help advance our understanding of stellar birth and evolution. The data used for this image were selected by Igor Chekalin (Russia), who participated in ESO's Hidden Treasures 2010 astrophotography competition. Igor's composition of the Orion Nebula was the seventh highest ranked entry in the competition, although another of Igor's images was the eventual overall winner. The Orion Nebula, also known as Messier 42, is one of the most easily recognisable and best-studied celestial objects. It is a huge complex of gas and dust where massive stars are forming and is the closest such region to the Earth. The glowing gas is so bright that it can be seen with the unaided eye and is a fascinating sight through a telescope. Despite its familiarity and closeness there is still much to learn about this stellar nursery. It was only in 2007, for instance, that the nebula was shown to be closer to us than previously thought: 1350 light-years, rather than about 1500 light-years. Astronomers have used the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile to observe the stars within Messier 42. They found that the faint red dwarfs in the star cluster associated with the glowing gas radiate much more light than had previously been thought, giving us further insights into this famous object and the stars that it hosts. The data collected for this science project, with no original intention to make a colour image, have now been reused to create the richly detailed picture of Messier 42 shown here. The image is a composite of several exposures taken through a total of five different filters. Light that passed through a red filter as well as light from a filter that

  13. Star Formation in the Orion Nebula I: Stellar Content

    CERN Document Server

    Muench, August; Hillenbrand, Lynne; Preibisch, Thomas

    2008-01-01

    The Orion Nebula is one of the most frequently observed nearby (<1 kiloparsec) star forming regions and, consequently, the subject of a large bibliography of observations and interpretation. The summary in this chapter is bounded spatially by the blister HII region, with sources beyond the central nebula that are part of the same dynamical clustering covered in other chapters in this book. Herein are discussed panchromatic observations of the massive OB stars, the general T Tauri population, the sub-stellar sources and variable stars within the Orion Nebula. First, a brief history of 400 years of observation of the Nebula is presented. As this history is marked clearly by revelations provided in each age of new technology, recent ultra-deep X-ray surveys and high resolution multi-epoch monitoring of massive binary systems and radio stars receive special attention in this review. Topics discussed include the kinematics, multiplicity, mass distribution, rotation, and circumstellar characteristics of the pre-...

  14. Complex molecules in the Orion Kleinmann-Low nebula

    Directory of Open Access Journals (Sweden)

    Despois D.

    2014-02-01

    Full Text Available In the framework of the delivery to the early Earth of extraterrestrial molecules, we have studied complex molecular species toward the Orion Kleinmann-Low nebula. This nebula is rich in molecules as well as in nascent stars and planetary systems. We focus here on HCOOCH3, CH3OCH3 and deuterated methanol. Upper limits on species of prebiotic interest like glycine were also obtained.

  15. THE NATURE AND FREQUENCY OF OUTFLOWS FROM STARS IN THE CENTRAL ORION NEBULA CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    O’Dell, C. R. [Department of Physics and Astronomy, Vanderbilt University, Box 1807-B, Nashville, TN 37235 (United States); Ferland, G. J. [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Henney, W. J. [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apartado Postal 3-72, 58090 Morelia, Michoacán, México (Mexico); Peimbert, M. [Instituto de Astronomia, Universidad Nacional Autónoma de México, Apdo, Postal 70-264, 04510 México D. F., México (Mexico); García-Díaz, Ma. T. [Instituto de Astronomia, Universidad Nacional Autónoma de México, Km 103 Carretera Tijuana-Ensenada, 22860 Ensenada, B.C., México (Mexico); Rubin, Robert H., E-mail: cr.odell@vanderbilt.edu [NASA/Ames Research Center, Moffett Field, CA 94035-0001 (United States)

    2015-10-15

    Recent Hubble Space Telescope images have allowed the determination with unprecedented accuracy of motions and changes of shocks within the inner Orion Nebula. These originate from collimated outflows from very young stars, some within the ionized portion of the nebula and others within the host molecular cloud. We have doubled the number of Herbig–Haro objects known within the inner Orion Nebula. We find that the best-known Herbig–Haro shocks originate from relatively few stars, with the optically visible X-ray source COUP 666 driving many of them. While some isolated shocks are driven by single collimated outflows, many groups of shocks are the result of a single stellar source having jets oriented in multiple directions at similar times. This explains the feature that shocks aligned in opposite directions in the plane of the sky are usually blueshifted because the redshifted outflows pass into the optically thick photon-dominated region behind the nebula. There are two regions from which optical outflows originate for which there are no candidate sources in the SIMBAD database.

  16. The Nature and Frequency of Outflows from Stars in the Central Orion Nebula Cluster

    CERN Document Server

    O'Dell, C R; Henney, W J; Peimbert, M; Garcia-Diaz, Ma T; Rubin, Robert H

    2015-01-01

    Recent Hubble Space Telescope images have allowed the determination with unprecedented accuracy of motions and changes of shocks within the inner Orion Nebula. These originate from collimated outflows from very young stars, some within the ionized portion of the nebula and others within the host molecular cloud. We have doubled the number of Herbig-Haro objects known within the inner Orion Nebula. We find that the best-known Herbig-Haro shocks originate from a relatively few stars, with the optically visible X-ray source COUP 666 driving many of them. While some isolated shocks are driven by single collimated outflows, many groups of shocks are the result of a single stellar source having jets oriented in multiple directions at similar times. This explains the feature that shocks aligned in opposite directions in the plane of the sky are usually blue shifted because the redshifted outflows pass into the optically thick Photon Dominated Region behind the nebula. There are two regions from which optical outflow...

  17. The three dimensional dynamic structure of the inner Orion Nebula

    CERN Document Server

    O'Dell, C R; Abel, N P; Ferland, G J; Arthur, S J

    2008-01-01

    The three dimensional structure of the brightest part of the Orion Nebula is assessed in the light of published and new data. We find that the widely accepted model of a concave blister of ionized material needs to be altered in the southwest direction from the Trapezium, where we find that the Orion-S feature is a separate cloud of very optically thick molecules within the body of ionized gas, which is probably the location of the multiple embedded sources that produce the outflows that define the Orion-S star formation region. Evidence for this cloud comes from the presence of H2CO lines in absorption in the radio continuum and discrepancies in the extinction derived from radio-optical and optical only emission. We present an equilibrium Cloudy model of the Orion-S cloud, which successfully reproduces many observed properties of this feature. We also report the discovery of an open-sided shell of [O III] surrounding the Trapezium stars, revealed through emission line ratio images and the onset of radiation ...

  18. Global X-ray properties of the Orion Nebula region

    CERN Document Server

    Feigelson, E D; Townsley, L; Garmire, G; Preibisch, T; Grosso, N; Montmerle, T; Münch, A; McCaughrean, M; Feigelson, Eric D.; Getman, Konstantin; Townsley, Leisa; Garmire, Gordon; Preibisch, Thomas; Grosso, Nicolas; Montmerle, Thierry; Muench, Augustus; Caughrean, Mark Mc

    2005-01-01

    Based on the Chandra Orion Ultradeep Project (COUP) observation, we establish the global X-ray properties of the stellar population associated with the Orion Nebula. Three components contribute roughly equally to the integrated COUP luminosity in the hard (2-8 keV) X-ray band: several OB stars, 822 lightly obscured cool stars in the Orion Nebula Cluster (ONC), and 559 heavily obscured stars. ONC stars 0.5-2 pc from the center show a spatial asymmetry consistent with violent relaxation in the stellar dynamics. The obscured COUP sources concentrate around both OMC-1 molecular cores; these small-scale structures indicate ages t < 0.1 Myr. The X-ray luminosity function (XLF) of the lightly obscured sample is roughly lognormal in shape. The obscured population is deficient in lower-luminosity stars, perhaps due to localized circumstellar material. Mass-stratified XLFs show that one-third of the Orion Nebula region hard-band emission is produced by the bright O6 star theta-1 Ori C and half is produced by lower m...

  19. Million-degree plasma pervading the extended Orion Nebula.

    Science.gov (United States)

    Güdel, Manuel; Briggs, Kevin R; Montmerle, Thierry; Audard, Marc; Rebull, Luisa; Skinner, Stephen L

    2008-01-18

    Most stars form as members of large associations within dense, very cold (10 to 100 kelvin) molecular clouds. The nearby giant molecular cloud in Orion hosts several thousand stars of ages less than a few million years, many of which are located in or around the famous Orion Nebula, a prominent gas structure illuminated and ionized by a small group of massive stars (the Trapezium). We present x-ray observations obtained with the X-ray Multi-Mirror satellite XMM-Newton, revealing that a hot plasma with a temperature of 1.7 to 2.1 million kelvin pervades the southwest extension of the nebula. The plasma flows into the adjacent interstellar medium. This x-ray outflow phenomenon must be widespread throughout our Galaxy.

  20. Infrared reflection nebulae in Orion Molecular Cloud 2

    Science.gov (United States)

    Pendleton, Yvonne; Werner, M. W.; Capps, R.; Lester, D.

    1986-01-01

    New observations of Orion Molecular Cloud 2 have been made from 1 to 100 microns using the NASA Infrared Telescope Facility and the Kuiper Airborne Observatory. An extensive program of polarimetry, photometry, and spectrophotometry has shown that the extended emission regions associated with two of the previously known near-infrared sources, IRS 1 and IRS 4, are infrared reflection nebulae, and that the compact sources IRS 1 and IRS 4 are the main luminosity sources in the cloud. The constraints from the far-infrared observations and an analysis of the scattered light from the IRS 1 nebula show that OMC-2/IRS 1 can be characterized by L of 500 solar luminosities or less and T of roughly 1000 K. The near-infrared albedo of the grains in the IRS 1 nebula is greater than 0.08.

  1. The Integral Field View of the Orion Nebula

    Directory of Open Access Journals (Sweden)

    Adal Mesa-Delgado

    2014-01-01

    Full Text Available This paper reviews the major advances achieved in the Orion Nebula through the use of integral field spectroscopy (IFS. Since the early work of Vasconcelos and collaborators in 2005, this technique has facilitated the investigation of global properties of the nebula and its morphology, providing new clues to better constrain its 3D structure. IFS has led to the discovery of shock-heated zones at the leading working surfaces of prominent Herbig-Haro objects as well as the first attempt to determine the chemical composition of Orion protoplanetary disks, also known as proplyds. The analysis of these morphologies using IFS has given us new insights into the abundance discrepancy problem, a long-standing and unresolved issue that casts doubt on the reliability of current methods used for the determination of metallicities in the universe from the analysis of H II regions. Results imply that high-density clumps and high-velocity flows may play an active role in the production of such discrepancies. Future investigations based on the large-scale IFS mosaic of Orion will be very valuable for exploring how the integrated effect of small-scale structures may have impact at larger scales in the framework of star-forming regions.

  2. Gas absorption and dust extinction towards the Orion Nebula Cluster

    CERN Document Server

    Hasenberger, Birgit; Alves, Joao; Wolk, Scott; Meingast, Stefan; Getman, Konstantin; Pillitteri, Ignazio

    2016-01-01

    We characterise the relation between the gas and dust content of the interstellar medium towards young stellar objects in the Orion Nebula Cluster. X-ray observations provide estimates of the absorbing equivalent hydrogen column density N_H based on spectral fits. Near-infrared extinction values are calculated from intrinsic and observed colour magnitudes (J-H) and (H-K_s) as given by the VISTA Orion A survey. A linear fit of the correlation between column density and extinction values A_V yields an estimate of the N_H/A_V ratio. We investigate systematic uncertainties of the results by describing and (if possible) quantifying the influence of circumstellar material and the adopted extinction law, X-ray models, and elemental abundances on the N_H/A_V ratio. Assuming a Galactic extinction law with R_V=3.1 and solar abundances by Anders & Grevesse (1989), we deduce an N_H/A_V ratio of (1.39 +- 0.14) x 10^21 cm^-2 mag^-1 for Class III sources in the Orion Nebula Cluster where the given error does not include...

  3. Detection of deuterium Balmer lines in the Orion Nebula

    CERN Document Server

    Hébrard, G; Vidal-Madjar, A; Walsh, J R; Ferlet, R

    2000-01-01

    The detection and first identification of the deuterium Balmer emissionlines, D-alpha and D-beta, in the core of the Orion Nebula is reported.Observations were conducted at the 3.6m Canada-France-Hawaii Telescope, usingthe Echelle spectrograph Gecko. These lines are very narrow and have identical11 km/s velocity shifts with respect to H-alpha and H-beta. They are probablyexcited by UV continuum fluorescence from the Lyman (DI) lines and arise fromthe interface between the HII region and the molecular cloud.

  4. Turbulence in the Ionized Gas of the Orion Nebula

    CERN Document Server

    Arthur, S J; Henney, W J

    2016-01-01

    In order to study the nature, origin, and impact of turbulent velocity fluctuations in the ionized gas of the Orion Nebula, we apply a variety of statistical techniques to observed velocity cubes. The cubes are derived from high resolving power ($R \\approx 40,000$) longslit spectroscopy of optical emission lines that span a range of ionizations. From Velocity Channel Analysis (VCA), we find that the slope of the velocity power spectrum is consistent with predictions of Kolmogorov theory between scales of 8 and 22 arcsec (0.02 to 0.05 pc). The outer scale, which is the dominant scale of density fluctuations in the nebula, approximately coincides with the autocorrelation length of the velocity fluctuations that we determine from the second order velocity structure function. We propose that this is the principal driving scale of the turbulence, which originates in the autocorrelation length of dense cores in the Orion molecular filament. By combining analysis of the non-thermal line widths with the systematic tr...

  5. The Integral Field View of the Orion Nebula

    CERN Document Server

    Mesa-Delgado, Adal

    2013-01-01

    This paper reviews the major advances achieved in the Orion Nebula through the use of integral field spectroscopy (IFS). Since the early work of Vasconcelos and collaborators in 2005, the capability of this technique has allowed to investigate the global properties of the nebula and its internal morphologies, providing new clues to constrain a better picture of its 3D structure. This spectroscopic technique has permitted the discovery of shock-heated zones at the leading working surfaces of prominent Herbig-Haro objects as well as the first attempt to determine the chemical composition of Orion protoplanetary disks, also known as proplyds. The analysis of these morphologies using IFS has given us new insights into the abundance discrepancy problem, a long-standing and unresolved issue that threatens the reliability of our current methods of determining metallicities in the Universe from the analysis of HII regions. Results imply that high-density clumps and high-velocity flows may play an active role in the p...

  6. Toward a Complete Census of the Low Mass IMF in the Orion Nebula Cluster

    Science.gov (United States)

    Robberto, Massimo; Andersen, Morten; Barman, Travis; Bellini, Andrea; da Rio, Nicola; de Mink, Selma; Hillenbrand, Lynne A.; Lu, Jessica R.; Luhman, Kevin; Manara, Carlo Felice; Meyer, Michael; Platais, Imants; Pueyo, Laurent; Soderblom, David; Soummer, Remi; Stahler, Steve; Tan, Jonathan Charles

    2015-08-01

    A 52-orbit Hubble Treasury Program is currently under way to investigate two fundamental questions of star formation: a) the low- mass tail of the IMF, down to a few Jupiter masses; b) the dynamical evolution of clusters, as revealed by stellar proper motions. The program targets the Orion Nebula Cluster using WFC3 and ACS in coordinated parallel mode to perform a synoptic survey in the 1.345micron H2O feature and in the F775W Ic broad-band. In this poster we present early results from the IR survey, aimed at discovering and classify all brown dwarfs and planetary-mass objects in the field, extending the IMF down to lowest masses formed by gravitational collapse. Using the latest generation of high contrast image processing we are also searching for faint companions, reaching down to sub-arcsecond separations and 10-4 flux ratios.

  7. Turbulence in the ionized gas of the Orion nebula

    Science.gov (United States)

    Arthur, S. J.; Medina, S.-N. X.; Henney, W. J.

    2016-12-01

    In order to study the nature, origin, and impact of turbulent velocity fluctuations in the ionized gas of the Orion nebula, we apply a variety of statistical techniques to observed velocity cubes. The cubes are derived from high resolving power (R ≈ 40 000) longslit spectroscopy of optical emission lines that span a range of ionizations. From velocity channel analysis (VCA), we find that the slope of the velocity power spectrum is consistent with predictions of Kolmogorov theory between scales of 8 and 22 arcsec (0.02 to 0.05 pc). The outer scale, which is the dominant scale of density fluctuations in the nebula, approximately coincides with the autocorrelation length of the velocity fluctuations that we determine from the second-order velocity structure function. We propose that this is the principal driving scale of the turbulence, which originates in the autocorrelation length of dense cores in the Orion molecular filament. By combining analysis of the non-thermal linewidths with the systematic trends of velocity centroid versus ionization, we find that the global champagne flow and smaller scale turbulence each contribute in equal measure to the total velocity dispersion, with respective root-mean-square widths of 4-5 km s-1. The turbulence is subsonic and can account for only one half of the derived variance in ionized density, with the remaining variance provided by density gradients in photoevaporation flows from globules and filaments. Intercomparison with results from simulations implies that the ionized gas is confined to a thick shell and does not fill the interior of the nebula.

  8. Mc Neil's Nebula in Orion: The Outburst History

    CERN Document Server

    Briceño, C; Hernández, J; Calvet, N; Hartmann, L; Megeath, T; Calkins, P BerlindM; Hoyer, S

    2004-01-01

    We present a sequence of I-band images obtained at the Venezuela 1m Schmidt telescope during the outburst of the nebula recently discovered by J.W. McNeil in the Orion L1630 molecular cloud. We derive photometry spanning the pre-outburst state and the brightening itself, a unique record including 14 epochs and spanning a time scale of ~5 years. We constrain the beginning of the outburst at some time between Oct. 28 and Nov. 15, 2003. The light curve of the object at the vertex of the nebula, the likely exciting source of the outburst, reveals that it has brightened ~5 magnitudes in about 4 months. The time scale for the nebula to develop is consistent with the light travel time, indicating that we are observing light from the central source scattered by the ambient cloud into the line of sight. We also show recent FLWO optical spectroscopy of the exciting source and of the nearby HH 22. The spectrum of the source is highly reddened; in contrast, the spectrum of HH 22 shows a shock spectrum superimposed on a c...

  9. Integral field spectroscopy of selected areas of the Bright bar and Orion-S cloud in the Orion nebula

    Science.gov (United States)

    Mesa-Delgado, A.; Núñez-Díaz, M.; Esteban, C.; López-Martín, L.; García-Rojas, J.

    2011-10-01

    We present integral field spectroscopy of two selected zones in the Orion nebula obtained with the Potsdam Multi-Aperture Spectrophotometer, covering the optical spectral range from 3500 to 7200 Å and with a spatial resolution of 1 arcsec. The observed zones are located on the prominent Bright bar and on the brightest area at the north-east of the Orion south cloud, both containing remarkable ionization fronts. We obtain maps of emission-line fluxes and ratios, electron density and temperatures, and chemical abundances. We study the ionization structure and morphology of both fields, whose ionization fronts show different inclination angles with respect to the plane of the sky. We find that the maps of electron density, O+/H+ and O/H ratios show a rather similar structure. We interpret this as produced by the strong dependence on density of the [O II] lines used to derive the O+ abundance, and that our nominal values of electron density - derived from the [S II] line ratio - may be slightly higher than the appropriate value for the O+ zone. We measure the faint recombination lines of O II in the field at the north-east of the Orion south cloud, allowing us to explore the so-called abundance discrepancy problem. We find a rather constant abundance discrepancy across the field and a mean value similar to that determined in other areas of the Orion nebula, indicating that the particular physical conditions of this ionization front do not contribute to this discrepancy. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC).

  10. SPECTROSCOPIC BINARIES IN THE ORION NEBULA CLUSTER AND NGC 2264

    Energy Technology Data Exchange (ETDEWEB)

    Kounkel, Marina; Hartmann, Lee; Mateo, Mario; Bailey, John I. III; Spencer, Meghin [Department of Astronomy, University of Michigan, 1085 S. University Street, Ann Arbor, MI 48109 (United States); Tobin, John J., E-mail: mkounkel@umich.edu [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands)

    2016-04-10

    We examine the spectroscopic binary population for two massive nearby regions of clustered star formation, the Orion Nebula Cluster (ONC) and NGC 2264, supplementing the data presented by Tobin et al. with more recent observations and more extensive analysis. The inferred multiplicity fraction up to 10 au based on these observations is 5.3 ± 1.2% for NGC 2264 and 5.8 ± 1.1% for the ONC; these values are consistent with the distribution of binaries in the field in the relevant parameter range. Eight of the multiple systems in the sample have enough epochs to perform an initial fit for the orbital parameters. Two of these sources are double-lined spectroscopic binaries; for them, we determine the mass ratio. Our reanalysis of the distribution of stellar radial velocities toward these clusters presents a significantly better agreement between stellar and gas kinematics than was previously thought.

  11. Spectroscopic Binaries in the Orion Nebula Cluster and NGC 2264

    CERN Document Server

    Kounkel, Marina; Tobin, John J; Mateo, Mario; III., John I Bailey; Spencer, Meghin

    2016-01-01

    We examine the spectroscopic binary population for two massive nearby regions of clustered star formation, the Orion Nebula Cluster and NGC 2264, supplementing the data presented by Tobin et al. (2009, 2015) with more recent observations and more extensive analysis. The inferred multiplicity fraction up to 10 AU based on these observations is $5.3\\pm 1.2$% for NGC 2264 and $5.8\\pm 1.1$% for the ONC; they are consistent with the distribution of binaries in the field in the relevant parameter range. Eight of the multiple systems in the sample have enough epochs to make an initial fit for the orbital parameters. Two of these sources are double-lined spectroscopic binaries; for them we determine the mass ratio. Our reanalysis of the distribution of stellar radial velocities towards these clusters presents a significantly better agreement between stellar and gas kinematics than was previously thought.

  12. Modeling the Orion nebula as an axisymmetric blister

    Science.gov (United States)

    Rubin, R. H.; Simpson, J. P.; Haas, M. R.; Erickson, E. F.

    1991-01-01

    The ionized gas in the Orion nebula is examined by means of axisymmetric modeling that is based on observational data from the ionized, neutral, and molecular regions. Nonsymmetrical features are omitted, radial dependence from the Trapezium is assumed, and azimuthal symmetry in the plane of the sky is used. Stellar properties and abundances of certain elements are described, and these data are used to compare the present axisymmetric-blister model to a previous spherical model. Strong singly-ionized emission that are visible near the Trapezium are found to originate in the ionization-bounded region in the dense Trapezium zone. The model can be more tightly constrained by adding near-IR data on noncentral zones for (Ar II), (AR III), (Ne II), and (S IV). The quadrant with the 'bar' creates an nonsymmetry that influences the observational data, and the model can therefore be improved with the additional data.

  13. A nebular analysis of the central Orion Nebula with MUSE

    CERN Document Server

    Leod, A F Mc; Ginsburg, A; Dale, J E; Ramsay, S; Testi, L

    2016-01-01

    A nebular analysis of the central Orion Nebula and its main structures is presented. We exploit MUSE integral field observations in the wavelength range 4595-9366 \\r{A} to produce the first O, S and N ionic and total abundance maps of a region spanning 6' x 5' with a spatial resolution of 0.2". We use the S$_{23}$ ( = ([SII]$\\lambda$6717,31+[SIII]$\\lambda$9068)/H$\\beta$) parameter, together with [OII]/[OIII] as an indicator of the degree of ionisation, to distinguish between the various small-scale structures. The only Orion Bullet covered by MUSE is HH 201, which shows a double component in the [FeII]$\\lambda$8617 line throughout indicating an expansion, and we discuss a scenario in which this object is undergoing a disruptive event. We separate the proplyds located south of the Bright Bar into four categories depending on their S$_{23}$ values, propose the utility of the S$_{23}$ parameter as an indicator of the shock-contribution to the excitation of line-emitting atoms, and show that the MUSE data is able...

  14. X-ray properties of protostars in the Orion Nebula

    CERN Document Server

    Prisinzano, L; Flaccomio, E; Stauffer, J R; Megeath, T; Rebull, L; Robberto, M; Smith, K; Feigelson, E D; Grosso, N; Wolk, S

    2007-01-01

    The origin and evolution of the X-rays in very young stellar objects (YSOs) are not yet well understood since it is very hard to observe YSOs in the protostellar phase. We study the X-ray properties of Class 0-I objects in the Orion Nebula Cluster (ONC) and compare them with those of the more evolved Class II and III members. Using Chandra Orion Ultradeep Project (COUP) data, we study the X-ray properties of stars in different evolutionary classes: luminosities, NH, temperatures and time variability are compared in order to understand if the interaction between the circumstellar material and the central object can influence the X-ray emission. We have assembled the deepest and most complete photometric catalog of objects in the ONC region from the UV to 8 microns using data from HST, WFI@2.2m ESO and ISPI@4m CTIO telescopes, and Spitzer IRAC. We select high probability candidate Class 0-I protostars, distinguishing between those having a spectral energy distribution which rises from K up to 8 microns (Class 0...

  15. PPAK integral field spectroscopy survey of the Orion nebula. Data release

    NARCIS (Netherlands)

    Sánchez, S. F.; Cardiel, N.; Verheijen, M. A. W.; Martín-Gordón, D.; Vilchez, J. M.; Alves, J.

    2007-01-01

    Aims:We present a low-resolution spectroscopic survey of the Orion nebula. The data are released for public use. We show the possible applications of this dataset analyzing some of the main properties of the nebula. Methods: We perform an integral field spectroscopy mosaic of an area of ~5 arcmin× 6

  16. Near-Infrared Variability in the Orion Nebula Cluster

    CERN Document Server

    Rice, Thomas S; Wolk, Scott J; Vaz, Luiz Paolo; Cross, N J G

    2015-01-01

    Using the United Kingdom Infrared Telescope on Mauna Kea, we have carried out a new near-infrared J, H, K monitoring survey of almost a square degree of the star-forming Orion Nebula Cluster with observations on 120 nights over three observing seasons, spanning a total of 894 days. We monitored ~15,000 stars down to J=20 using the WFCAM instrument, and have extracted 1203 significantly variable stars from our data. By studying variability in young stellar objects (YSOs) in the H-K, K color-magnitude diagram, we are able to distinguish between physical mechanisms of variability. Many variables show color behavior indicating either dust-extinction or disk/accretion activity, but we find that when monitored for longer periods of time, a number of stars shift between these two variability mechanisms. Further, we show that the intrinsic timescale of disk/accretion variability in young stars is longer than that of dust-extinction variability. We confirm that variability amplitude is statistically correlated with ev...

  17. The bimodal initial mass function in the Orion Nebula Cloud

    CERN Document Server

    Drass, H; Chini, R; Bayo, A; Hackstein, M; Hoffmeister, V; Godoy, N; Vogt, N

    2016-01-01

    Due to its youth, proximity and richness the Orion Nebula Cloud (ONC) is an ideal testbed to obtain a comprehensive view on the Initial Mass Function (IMF) down to the planetary mass regime. Using the HAWK-I camera at the VLT, we have obtained an unprecedented deep and wide near-infrared JHK mosaic of the ONC (90% completeness at K~19.0mag, 22'x28). Applying the most recent isochrones and accounting for the contamination of background stars and galaxies, we find that ONC's IMF is bimodal with distinct peaks at about 0.25 and 0.025 M_sun separated by a pronounced dip at the hydrogen burning limit (0.08 M_sun), with a depth of about a factor 2-3 below the log-normal distribution. Apart from ~920 low-mass stars (M 0.005 M_sun, hence about ten times more substellar candidates than known before. The substellar IMF peak at 0.025 M_sun could be caused by BDs and IPMOs which have been ejected from multiple systems during the early star-formation process or from circumstellar disks.

  18. A MUSE map of the central Orion Nebula (M 42)

    CERN Document Server

    Weilbacher, Peter M; Kollatschny, Wolfram; Ginsburg, Adam; McLeod, Anna F; Kamann, Sebastian; Sandin, Christer; Palsa, Ralf; Wisotzki, Lutz; Bacon, Roland; Selman, Fernando; Brinchmann, Jarle; Caruana, Joseph; Kelz, Andreas; Martinsson, Thomas; Pécontal-Rousset, Arlette; Richard, Johan; Wendt, Martin

    2015-01-01

    We present a new integral-field spectroscopic dataset of the central part of the Orion Nebula (M 42), observed with the MUSE instrument at the ESO VLT. We reduced the data with the public MUSE pipeline. The output products are two FITS cubes with a spatial size of ~5.9'x4.9' (corresponding to ~0.76 pc x 0.63 pc) and a contiguous wavelength coverage of 4595...9366 Angstrom, spatially sampled at 0.2". We provide two versions with a sampling of 1.25 Angstrom and 0.85 Angstrom in dispersion direction. Together with variance cubes these files have a size of 75 and 110 GiB on disk. They represent one of the largest integral field mosaics to date in terms of information content. We make them available for use in the community. To validate this dataset, we compare world coordinates, reconstructed magnitudes, velocities, and absolute and relative emission line fluxes to the literature and find excellent agreement. We derive a two-dimensional map of extinction and present de-reddened flux maps of several individual emi...

  19. The substellar content of the Orion Nebula Cluster

    Science.gov (United States)

    Drass, Holger; Chini, Rolf; Nuernberger, Dieter; Bayo, Amelia; Hackstein, Moritz; Morales-Calderón, Maria; Hoffmeister, Vera; Haas, Martin

    2013-07-01

    The Substellar Initial Mass Function (SIMF) of many star-forming regions is still poorly known but the detailed knowledge of its shape will help to distinguish among the substellar formation theories. The Orion Nebula Cluster (ONC) is one of the most extensively studied star forming regions. We here present deep, wide-field JHK observations of the ONC taken with HAWK-I@VLT. These observations extend the IMF into the brown dwarf and free-floating planetary mass regime with unprecedented sensitivity. To obtain a clean sample of ONC members, we exclude potential background sources with the help of CO extinction maps. Masses are assigned by means of evolutionary tracks in the H vs. J-H Color-Magnitude Diagram (CMD). Besides the well known stellar peak at ~0.25 M_sun we find a pronounced second peak at ~0.04 M_sun in the SIMF and indications for a third rise in the free-floating planetary mass regime.

  20. The Orion Nebula Cluster as a Paradigm of Star Formation

    Science.gov (United States)

    Robberto, Massimo

    2014-10-01

    We propose a 52-orbit Treasury Program to investigate two fundamental questions of star formation: a) the low-mass tail of the IMF, down to a few Jupiter masses; b) the dynamical evolution of clusters, as revealed by stellar proper motions. We target the Orion Nebula Cluster (ONC) using WFC3 and ACS in coordinated parallel mode to perform a synoptic survey in the 1.345micron H2O feature and Ic broad-band. Our main objectives are: 1) to discover and classify ~500 brown dwarfs and planetary-mass objects in the field, extending the IMF down to lowest masses formed by gravitational collapse. Using the latest generation of high contrast image processing we will also search for faint companions, reaching down to sub-arcsecond separations and 1E-4 flux ratios. 2) to derive high precision (~0.2km/s) relative proper motions of low-mass stars and substellar objects (about 1000 sources total), leveraging on first epoch data obtained by our previous HST Treasury Program about 10 years ago. These data will unveil the cluster dynamics: velocity dispersion vs. mass, substructures, and the fraction of escaping sources. Only HST can access the IR H2O absorption feature sensitive to the effective temperature of substellar objects, while providing the exceptionally stable PSF needed for the detection of faint companions, and the identical ACS platform for our second epoch proper-motion survey. This program will provide the definitive HST legacy dataset on the ONC. Our High-Level Science Products will be mined by the community, both statistically to constrain competing theories of star formation, and to study in depth the multitude of exotic sources harboured by the cluster.

  1. Stellar and circumstellar properties of visual binaries in the Orion Nebula Cluster

    CERN Document Server

    Correia, S; Reipurth, B; Zinnecker, H; Daemgen, S; Petr-Gotzens, M G; Koehler, R; Ratzka, Th; Aspin, C; Konopacky, Q M; Ghez, A M

    2013-01-01

    Our general understanding of multiple star and planet formation is primarily based on observations of young multiple systems in low density regions like Tau-Aur and Oph. Since many, if not most, of the stars are born in clusters, observational constraints from young binaries in those environments are fundamental for understanding both the formation of multiple systems and planets in multiple systems throughout the Galaxy. We build upon the largest survey for young binaries in the Orion Nebula Cluster (ONC) which is based on Hubble Space Telescope observations to derive both stellar and circumstellar properties of newborn binary systems in this cluster environment. We present Adaptive Optics spatially-resolved JHKL'-band photometry and K-band R$\\sim$\\,5000 spectra for a sample of 8 ONC binary systems from this database. We characterize the stellar properties of binary components and obtain a census of protoplanetary disks through K-L' color excess. For a combined sample of ONC binaries including 7 additional s...

  2. TIMMI2 Images the Heart of the Orion Nebula

    Science.gov (United States)

    2001-03-01

    New Vistas with Powerful Thermal Infrared Instrument at La Silla Summary A new astronomical instrument, TIMMI2 , has just been installed on the ESO 3.6-m telescope at La Silla. The first images have just been obtained and hold great promise for future research programmes with this facility. The Thermal Infrared MultiMode Instrument was built in a collaboration between ESO and a consortium headed by the Jena University Observatory (Germany). It detects infrared radiation in the 5-24 µm mid-IR spectral region. It is particularly well suited for observations of the complex processes that take place in the innermost regions of star-forming clouds. It is also a forerunner of a similar, but even more powerful instrument to be installed at the 8.2-m VLT telescopes on Paranal during the next years. Among the first images are some of the most penetrating, mid-infrared views ever obtained of the central region of the Orion Nebula . PR Photo 12a/01 : Location of the BN/KL complex in the Orion Nebula. PR Photo 12b/01 : TIMMI2 photo of the BN/KL complex at wavelength 10.3 µm . PR Photo 12c/01 : TIMMI2 photo of the BN/KL complex at wavelength 20.0 µm . PR Photo 12d/01 : Composite "thermal" photo of the BN/KL complex . PR Photo 12e/01 : The TIMMI2 instrument at the ESO 3.6-m telescope. Mid-infrared TIMMI2 images of a starforming region in Orion ESO PR Photo 10a/01 ESO PR Photo 12a/01 [Preview - JPEG: 347 x 400 pix - 93k] [Normal - JPEG: 694 x 800 pix - 224k] [Hi-Res - JPEG: 2601 x 3000 pix - 1.4M] ESO PR Photo 10b/01 ESO PR Photo 12b/01 [Preview - JPEG: 250 x 400 pix - 42k] [Normal - JPEG: 500 x 800 pix - 120k] ESO PR Photo 10c/01 ESO PR Photo 12c/01 [Preview - JPEG: 250 x 400 pix - 78k] [Normal - JPEG: 500 x 800 pix - 200k] ESO PR Photo 10d/01 ESO PR Photo 12d/01 [Preview - JPEG: 250 x 400 pix - 78k] [Normal - JPEG: 500 x 800 pix - 208k] Caption : A series of mid-infrared images of the BN/KL complex , a star-forming region deep inside the Orion Nebula , was recently obtained

  3. Symposium on the Orion Nebula to Honor Henry Draper, New York University, New York, NY, December 4, 5, 1981, Proceedings

    Science.gov (United States)

    Glassgold, A. E. (Editor); Huggins, P. J. (Editor); Schucking, E. L.

    1982-01-01

    The present conference on astronomical studies of the Orion Nebula covers molecular clouds in Orion, the use of the nebula's cloak as a model for gas super-shells around OB associations, optical and UV data concerning the nebula's physical conditions, the presence of atomic carbon in Orion, large scale distribution of far-IR and sub-mm line emission, star formation studies in the IR, gas dynamics in the circumstellar nebula of the Becklin-Neugebauer source, maser sources and far-IR CO line emission in Orion-KL, and synthesis maps of mm molecular lines. Also discussed are Orion's star distributions, core region nebular condensations, energetic molecular flows in star-forming cloud cores, IR observations of HH objects, compact continuum radio sources, the SiO maser, shock waves, and the chemical evolution of OB associations.

  4. The Einstein survey of the young stars in the Orion Nebula

    Science.gov (United States)

    Zoonematkermani, S.; Caillault, J.-P.

    1987-01-01

    The Orion Nebula is the best studied site of recent star formation in the Galaxy. The complete Einstein Observatory survey of the Orion Nebula covering a 2 deg x 2 deg region centered on the Trapezium is reported. An X-ray mosaic is presented for the Nebula along with a complete X-ray catalogue for this very young cluster. Approximately 150 distinct sources were found in this 4 sq deg region; spectral types and colors were obtained for about 1/2 of the optical counterparts of these sources. Comparison of the variability of the Orion X-ray sources with those found in the Rho Ophiuchi cloud leads to the conclusion that the Orion sources' variability is also likely to result from continual flaring activities. Eleven new late B stars associated with X-ray emission far exceeding that expected from early type stars were discovered. The X-rays may originate from pre-main sequence companions to these stars; a T-Tauri star of the same age would have the correct L sub x. Comparison of the solar type stars in Orion with those in the Pleiades, the Hyades, and the field suggests that the decay of activity with age is most appropriately described by an exponential, rather than a power law fit.

  5. Tearing the Veil: interaction of the Orion Nebula with its neutral environment

    CERN Document Server

    van der Werf, Paul P; O'Dell, C R

    2012-01-01

    We present HI 21cm observations of the Orion Nebula, obtained with the Karl G. Jansky Very Large Array, at an angular resolution of 7.2"x5.7" and a velocity resolution of 0.77 km/s. Our data reveal HI absorption towards the radio continuum of the HII region, and HI emission arising from the Orion Bar photon-dominated region (PDR) and from the Orion-KL outflow. In the Orion Bar PDR, the HI signal peaks in the same layer as the H2 near-infrared vibrational line emission, in agreement with models of the photodissociation of H2. The gas temperature in this region is approximately 540K, and the HI abundance in the interclump gas in the PDR is 5-10% of the available hydrogen nuclei. Most of the gas in this region therefore remains molecular. Mechanical feedback on the Veil manifests itself through the interaction of ionized flow systems in the Orion Nebula, in particular the Herbig-Haro object HH202, with the Veil. These interactions give rise to prominent blueward velocity shifts of the gas in the Veil. The unambi...

  6. The HST/ACS Atlas of Protoplanetary Disks in the Great Orion Nebula

    CERN Document Server

    Ricci, Luca; Soderblom, David R

    2008-01-01

    We present the atlas of protoplanetary disks in the Orion Nebula based on the ACS/WFC images obtained for the HST Treasury Program on the Orion Nebula Cluster. The observations have been carried out in 5 photometric filters nearly equivalent to the standard B, V, Halpha, I, and z passbands. Our master catalog lists 178 externally ionized proto-planetary disks (proplyds), 28 disks seen only in absorption against the bright nebular background (silhouette disks), 8 disks seen only as dark lanes at the midplane of extended polar emission (bipolar nebulae or reflection nebulae) and 5 sources showing jet emission with no evidence of neither external ionized gas emission nor dark silhouette disks. Many of these disks are associated with jets seen in Halpha and circumstellar material detected through reflection emission in our broad-band filters; approximately 2/3 have identified counterparts in x-rays. A total of 47 objects (29 proplyds, 7 silhouette disks, 6 bipolar nebulae, 5 jets with no evidence of proplyd emiss...

  7. The extinction map of the OMC-1 molecular cloud behind the Orion Nebula

    CERN Document Server

    Scandariato, Gaetano; Pagano, Isabella; Hillenbrand, Lynne

    2011-01-01

    Our main goal is to derive a new extinction map of the OMC-1, obtaining information about the structure of the OMC-1 and the Orion Nebula Cluster. The most recent near-infrared catalog of stars is used to study the distribution of reddening across a ~0.3 deg^2 area covering the Orion Nebula Cluster. On the basis of the observed (H,H-K_S) diagram, we establish a criterion for disentangling contaminants from bona-fide cluster members. For contaminant stars, interstellar reddenings are estimated by comparison with a synthetic galactic model. A statistical analysis is then performed to consistently account for local extinction, reddening and star-counts analysis. We derive the extinction map of the OMC-1 with angular resolution 30). The Orion Nebula extinction map is more irregular and optically thinner, with A_V of the order of a few magnitudes. Both maps are consistent with the optical morphology, in particular the Dark Bay to the north-east of the Trapezium. Both maps also show the presence of a north-south hi...

  8. Large Scale Flows from Orion-South

    CERN Document Server

    Henney, W J; Zapata, L A; Garcia-Diaz, M T; Rodríguez, L F; Robberto, M; Zapata, Luis A.; Garcia-Diaz, Ma. T.; Rodriguez, Luis F.; Robberto, Massimo

    2007-01-01

    Multiple optical outflows are known to exist in the vicinity of the active star formation region called Orion-South (Orion-S). We have mapped the velocity of low ionization features in the brightest part of the Orion Nebula, including Orion-S, and imaged the entire nebula with the Hubble Space Telescope. These new data, combined with recent high resolution radio maps of outflows from the Orion-S region, allow us to trace the origin of the optical outflows. It is confirmed that HH 625 arises from the blueshifted lobe of the CO outflow from 136-359 in Orion-S while it is likely that HH 507 arises from the blueshifted lobe of the SiO outflow from the nearby source 135-356. It is likely that redshifted lobes are deflected within the photon dominated region behind the optical nebula. This leads to a possible identification of a new large shock to the southwest from Orion-S as being driven by the redshifted CO outflow arising from 137-408. The distant object HH 400 is seen to have two even further components and th...

  9. X-rays from HH210 in the Orion nebula

    CERN Document Server

    Grosso, N; Getman, K V; Kästner, J H; Bally, J; McCaughrean, M J; Grosso, Nicolas; Feigelson, Eric D.; Getman, Konstantin V.; Kastner, Joel H.; Bally, John; Caughrean, Mark J. Mc

    2006-01-01

    We report the detection during the Chandra Orion Ultradeep Project (COUP) of two soft, constant, and faint X-ray sources associated with the Herbig-Haro object HH210. HH210 is located at the tip of the NNE finger of the emission line system bursting out of the BN-KL complex, northwest of the Trapezium cluster in the OMC-1 molecular cloud. Using a recent Halpha image obtained with the ACS imager on board HST, and taking into account the known proper motions of HH210 emission knots, we show that the position of the brightest X-ray source, COUP703, coincides with the emission knot 154-040a of HH210, which is the emission knot of HH210 having the highest tangential velocity (425 km/s). The second X-ray source, COUP704, is located on the complicated emission tail of HH210 close to an emission line filament and has no obvious optical/infrared counterpart. Spectral fitting indicates for both sources a plasma temperature of ~0.8 MK and absorption-corrected X-ray luminosities of about 1E30 erg/s (0.5-2.0 keV). These X...

  10. Structural details of the Orion Nebula - Detection of a network of stringlike ionized features

    Science.gov (United States)

    Yusef-Zadeh, F.

    1990-09-01

    Continuum observations of the Orion Nebula, obtained at 20 cm using the A, B, C, and D configurations of the VLA during 1986-1987, are reported. Radio images of resolution 1.8 x 1.6 arcsec are presented and analyzed, with a focus on (1) the complex cone structure of M 42 and (2) an extended network of bright stringlike features concentrated near the Trapezium cluster. Possible theoretical explanations of these features are explored, starting from the blister model of H II regions developed by Tenorio and Tagle (1979).

  11. Velocity Structure in the Orion Nebula. I. Spectral Mapping in Low-Ionization Lines

    CERN Document Server

    Garcia-Diaz, M T; Garcia-Diaz, Ma. T.

    2006-01-01

    High-dispersion echelle spectroscopy in optical forbidden lines of O^0, S^+, and S^2+ is used to construct velocity-resolved images and electron density maps of the inner region of the Orion nebula with a resolution of 10 km s-1 x 3" x 2". Among the objects and regions newly discovered in this study are (1) the Diffuse Blue Layer: an extended layer of moderately blue-shifted, low-density, low-ionization emission in the southeast region of the nebula; (2) the Red Bay: a region to the east of the Trapezium where the usual correlation between velocity and ionization potential is very weak, and where the emitting layer is very thick; and (3) HH 873: a new redshifted jet to the southwest of the Trapezium.

  12. HERSCHEL FAR-INFRARED PHOTOMETRIC MONITORING OF PROTOSTARS IN THE ORION NEBULA CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Billot, N. [NASA Herschel Science Center, California Institute of Technology, 770 S. Wilson Ave, Pasadena, CA 91125 (United States); Morales-Calderon, M.; Stauffer, J. R. [Spitzer Science Center, Caltech, Pasadena, CA 91125 (United States); Megeath, S. T. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Whitney, B., E-mail: billot@iram.es [Space Science Institute, Boulder, CO 80301 (United States)

    2012-07-10

    We have obtained time series observations of the Orion Nebula Cluster at 70 {mu}m and 160 {mu}m from the Herschel/PACS Photometer. This represents the first wide-field far-infrared photometric monitoring of a young star-forming region. The acquired 35' Multiplication-Sign 35' maps show complex extended structures, with unprecedented detail, that trace the interaction between the molecular gas and the young hot stars. We detect 43 protostars, most of which are situated along the integral-shaped filament extending from the Orion nebula, through OMC 2 and OMC 3. We present high-reliability light curves for some of these objects using the first six epochs of our observing program spread over 6 weeks. We find amplitude variations in excess of 20% for a fraction of the detected protostars over periods as short as a few weeks. This is inconsistent with the dynamical timescales of cool far-IR emitting material that orbits at hundreds of AU from the protostar, and it suggests that the mechanism(s) responsible for the observed variability originates from the inner region of the protostars, likely driven by variable mass accretion.

  13. Spatial observations of the Orion Nebula in the unidentified 3.28 micron feature

    Science.gov (United States)

    Sellgren, K.

    1981-01-01

    The unidentified infrared emission at a wavelength of 3.28 microns has been mapped in a 5 x 5 arcmin region of the Orion Nebula at a resolution of 30 arcsec along with continuum thermal emission at 3.5 microns in order to gain information on the probable source of the unidentified feature. The 3.28-micron emission is found to be extended over much of the nebula with a distribution very different from that of the 3.5-micron continuum. The ratio of 3.28-micron to 3.5-micron flux density is observed to range from a value of 7 in the Orion ionization ridge to less than 0.15 towards the Becklin-Neugebauer object, and to generally be larger toward the edges of the emitting region than toward the Trapezium. From the observations, it is concluded that the 3.28-micron emission originates in the ionization front between the foreground ionized gas and background molecular cloud, and may be due to thermal emission from complex, less volatile organic substances in grain mantles.

  14. Rotation-disk connection for very low mass and substellar objects in the Orion Nebula Cluster

    CERN Document Server

    Rodriguez-Ledesma, Maria V; Eislöffel, Jochen

    2010-01-01

    Angular momentum loss requires magnetic interaction between the forming star and both the circumstellar disk and the magnetically driven outflows. In order to test these predictions many authors have investigated a rotation-disk connection in pre-main sequence objects with masses larger than about 0.4Msun. For brown dwarfs this connection was not investigated as yet because there are very few samples available. We aim to extend this investigation well down into the substellar regime for our large sample of BDs in the Orion Nebula Cluster, for which we have recently measured rotational periods. In order to investigate a rotation-disk correlation, we derived near-infrared (NIR) excesses for a sample of 732 periodic variables in the Orion Nebula Cluster with masses ranging between 1.5-0.02 Msun and whose IJHK colors are available. Circumstellar NIR excesses were derived from the Delta[I-K] index. We performed our analysis in three mass bins.We found a rotation-disk correlation in the high and intermediate mass r...

  15. Near-infrared and ultraviolet spectrophotometry of the young planetary nebula Hubble 12

    Science.gov (United States)

    Rudy, Richard J.; Rossano, George S.; Erwin, Peter; Puetter, R. C.; Feibelman, Walter A.

    1993-01-01

    The young planetary nebula Hubble 12 is observed using near-IR and UV spectrophotometry. The brightness of the O I lines, which is greater than in any other planetary nebula yet measured, indicates that fluorescent excitation by stellar continuum is the principal mechanism generating these lines. Extinction, electron density, and electron temperature are determined using infrared measurements combined with UV data and published optical observations. The range in extinction, density, and temperature implies that, within the ionized region, pockets of emission with distinctly different conditions exist. Logarithmic abundances for helium, oxygen, and sulfur are presented.

  16. Reconstructing the low-mass IMF of the Orion Nebula Cluster through HST photometry in the H2O band at 1.4micron

    Science.gov (United States)

    Giulia Ubeira Gabellini, Maria; Ubeda, Leonardo; Da Rio, Nicola; Robberto, Massimo; HST Treasury Program on the Orion Nebula Team

    2016-01-01

    We present a progress report on a 52-orbit Hubble Treasury Program aimed at investigating two key characteristics of the Orion Nebula Cluster: a) the low-mass tail of the IMF, down to a few Jupiter masses; b) the dynamical evolution of clusters, as revealed by stellar proper motions. The program, completed a few weeks ago, uses WFC3 and ACS in coordinated parallel mode to perform a synoptic survey in the 1.345micron H2O feature and in the F775W Ic broad-band. In this contribution we concentrate on the WFC3 photometry; the strength of the H2O absorption feature is strongly correlated with the effective temperature of low-mass stars, brown dwarfs and planetary-mass objects, and allows extending the IMF down to lowest masses formed by gravitational collapse. We present the first results on the central and densest part of the cluster.

  17. Young Planetary Nebulae: Hubble Space Telescope Imaging and a New Morphological Classification System

    CERN Document Server

    Sahai, Raghvendra; Villar, Gregory G

    2011-01-01

    Using Hubble Space Telescope images of 119 young planetary nebulae, most of which have not previously been published, we have devised a comprehensive morphological classification system for these objects. This system generalizes a recently devised system for pre-planetary nebulae, which are the immediate progenitors of planetary nebulae (PNs). Unlike previous classification studies, we have focussed primarily on young PNs rather than all PNs, because the former best show the influences or symmetries imposed on them by the dominant physical processes operating at the first and primary stage of the shaping process. Older PNs develop instabilities, interact with the ambient interstellar medium, and are subject to the passage of photoionization fronts, all of which obscure the underlying symmetries and geometries imposed early on. Our classification system is designed to suffer minimal prejudice regarding the underlying physical causes of the different shapes and structures seen in our PN sample, however, in many...

  18. The Structure, Dynamics and Star Formation Rate of the Orion Nebula Cluster

    CERN Document Server

    Da Rio, Nicola; Jaehnig, Karl

    2014-01-01

    The spatial morphology and dynamical status of a young, still-forming stellar cluster provide valuable clues on the conditions during the star formation event and the processes that regulated it. We analyze the Orion Nebula Cluster (ONC), utilizing the latest censuses of its stellar content and membership estimates over a large wavelength range. We determine the center of mass of the ONC, and study the radial dependence of angular substructure. The core appears rounder and smoother than the outskirts, consistent with a higher degree of dynamical processing. At larger distances the departure from circular symmetry is mostly driven by the elongation of the system, with very little additional substructure, indicating a somewhat evolved spatial morphology or an expanding halo. We determine the mass density profile of the cluster, which is well fitted by a power law that is slightly steeper than a singular isothermal sphere. Together with the ISM density, estimated from average stellar extinction, the mass content...

  19. Magnetic fields, winds and X-rays of massive stars in the Orion Nebula Cluster

    CERN Document Server

    Petit, V; Drissen, L; Montmerle, T; Alecian, E

    2008-01-01

    In massive stars, magnetic fields are thought to confine the outflowing radiatively-driven wind, resulting in X-ray emission that is harder, more variable and more efficient than that produced by instability-generated shocks in non-magnetic winds. Although magnetic confinement of stellar winds has been shown to strongly modify the mass-loss and X-ray characteristics of massive OB stars, we lack a detailed understanding of the complex processes responsible. The aim of this study is to examine the relationship between magnetism, stellar winds and X-ray emission of OB stars. In conjunction with a Chandra survey of the Orion Nebula Cluster, we carried out spectropolarimatric ESPaDOnS observations to determine the magnetic properties of massive OB stars of this cluster.

  20. Ionization fronts and shocked flows - The structure of the Orion Nebula at 0.1 arcsec

    Science.gov (United States)

    Hester, J. Jeff; Gilmozzi, R.; O'Dell, C. R.; Faber, S. M.; Campbell, Bel; Kelsall, T.

    1991-01-01

    Initial results are presented from images of the Orion Nebula obtained with the HST Wide-Field Camera with a resolution of better than about 10 to the 15th cm. The morphology of the forbidden S II emission is markedly different from that seen in H-beta and forbidden O II. The forbidden S II is dominated by filamentary features with widths between 0.1 and 1 arcsesc which sharply highlight ionization fronts moving into dense neutral material. While the surfaces into which these fronts are moving are textured, subarcsec clumps with high density contrast are uncommon. The fields contains a number of HH objects whose structure is revealed by the HST, and which are described.

  1. Ionization fronts and shocked flows - The structure of the Orion Nebula at 0. 1 arcsec

    Energy Technology Data Exchange (ETDEWEB)

    Hester, J.J.; Gilmozzi, R.; O' Dell, C.R.; Faber, S.M.; Campbell, B.; Kelsall, T. (California Institute of Technology, Pasadena (USA) Space Telescope Science Institute, Baltimore, MD (USA) ESA, Space Science Dept., Noordwijk (Netherlands) Rice Univ., Houston, TX (USA) Lick Observatory, Santa Cruz, CA (USA) New Mexico Univ., Albuquerque (USA) NASA, Goddard Space Flight Center, Greenbelt, MD (USA))

    1991-03-01

    Initial results are presented from images of the Orion Nebula obtained with the HST Wide-Field Camera with a resolution of better than about 10 to the 15th cm. The morphology of the forbidden S II emission is markedly different from that seen in H-beta and forbidden O II. The forbidden S II is dominated by filamentary features with widths between 0.1 and 1 arcsesc which sharply highlight ionization fronts moving into dense neutral material. While the surfaces into which these fronts are moving are textured, subarcsec clumps with high density contrast are uncommon. The fields contains a number of HH objects whose structure is revealed by the HST, and which are described. 29 refs.

  2. Quantitative Evidence for an Intrinsic Age Spread in the Orion Nebula Cluster

    CERN Document Server

    Reggiani, M; Da Rio, N; Meyer, M R; Soderblom, D R; Ricci, L

    2011-01-01

    Aims. We present a study of the distribution of stellar ages in the Orion Nebula Cluster (ONC) based on accurate HST photometry taken from the HST Treasury Program observations of the ONC utilizing the most recent estimate of the cluster's distance (Menten et al. 2007). We investigate the presence of an intrinsic age spread in the region and a possible trend of age with the spatial distribution. Methods. We estimate the extinction and accretion luminosity towards each source by performing synthetic photometry on an empirical calibration of atmospheric models (Da Rio et al. 2010) using the package Chorizos (Maiz-Apellaniz 2004). The position of the sources in the HR-diagram is compared with different theoretical isochrones to estimate the mean cluster age and age dispersion. Through Monte Carlo simulations we quantify the amount of intrinsic age spread in the region, taking into account uncertainties on the distance, spectral type, extinction, unresolved binaries, accretion and photometric variability. Results...

  3. A Multi-color Optical Survey of the Orion Nebula Cluster. I. The Catalog

    Science.gov (United States)

    Da Rio, N.; Robberto, M.; Soderblom, D. R.; Panagia, N.; Hillenbrand, L. A.; Palla, F.; Stassun, K.

    2009-08-01

    We present U, B, V, I broadband, 6200 Å TiO mediumband, and Hα narrowband photometry of the Orion Nebula Cluster (ONC) obtained with the WFI imager at the ESO/MPI 2.2 telescope at La Silla Observatory. The nearly simultaneous observations cover the entire ONC in a field of about 34 × 34 arcmin. They enable us to determine stellar colors avoiding the additional scatter in the photometry induced by stellar variability typical of pre-main-sequence stars. We identify 2612 point-like sources in the I band; 58%, 43%, and 17% of them are also detected in V, B, and U, respectively. 1040 sources are identified in the Hα band. In this paper we present the observations, the calibration techniques adopted, and the resulting catalog. We show the derived color-magnitude diagram of the population and discuss the completeness of our photometry. We define a spectrophotometric TiO index that takes into account the fluxes in the V, I, and TiO bands. Comparing it with spectral types of ONC members in the literature, we find a correlation between the index and the spectral type valid for M-type stars, which is accurate to better than 1 spectral subclass for M3-M6 types and better than 2 spectral subclasses for M0-M2 types.. This allows us to newly classify 217 stars. In a similar way, we subtract from our Hα photometry the photospheric continuum at its wavelength, deriving calibrated line excess for the full sample. This represents the largest Hα star catalog obtained to date on the ONC. This data set enables a full re-analysis of the properties of the pre-main-sequence population in the Orion Nebula Cluster to be presented in an accompanying paper.

  4. Star formation and chemical complexity in the Orion nebula: A new view with the IRAM and ALMA interferometers

    Science.gov (United States)

    Baudry, Alain; Brouillet, Nathalie; Despois, Didier

    2016-11-01

    The Orion nebula is one of the most observed celestial regions in the Milky Way. It is an active massive star-forming region, especially well studied in the millimeter and submillimeter domains that allow us to unveil the cool and obscured regions in which stars are being formed. After a brief introduction to the main properties of a radio telescope, we recall that the most sensitive radio interferometers, the IRAM mm array and, especially, the recently built ALMA millimeter/submillimeter array, offer an outstanding spatial resolution reaching the sub-arcsecond scale, or even about 10 milli-arcseconds for ALMA (about four times the Earth's orbit radius at the Orion distance). These interferometers can reveal the fine spatial details of the Orion clouds of gas and dust within which new stars and associated planetary systems are being formed. The high spectral resolution and sensitivity of both interferometers and the broad instantaneous bandwidth offered by ALMA allowed us to map the emission from a number of complex organic molecules, to estimate the molecular abundances, and to address some important aspects of the molecular complexity in Orion. Our observations do not lead to a unique molecular formation and excitation scheme, but the chemistry at work in the proto-stellar 'fragments' at the center of the Orion nebula can be compared with the chemistry prevailing in comets of the Solar system. We have underlined the possible links between the prebiotic molecules observed in space and the chemistry leading to the early terrestrial life.

  5. Bootstrapping dielectronic recombination from second-row elements and the Orion Nebula

    CERN Document Server

    Badnell, N R; Gorczyca, T W; Nikolic, D; Wagle, G A

    2015-01-01

    Dielectronic recombination (DR) is the dominant recombination process for most heavy elements in photoionized clouds. Accurate DR rates for a species can be predicted when the positions of autoionizing states are known. Unfortunately such data are not available for most third and higher-row elements. This introduces an uncertainty that is especially acute for photoionized clouds, where the low temperatures mean that DR occurs energetically through very low-lying autoionizing states. This paper discusses S$^{2+} \\rightarrow$ S$^+$ DR, the process that is largely responsible for establishing the [S~III]/[S~II] ratio in nebulae. We derive an empirical rate coefficient using a novel method for second-row ions, which do have accurate data. Photoionization models are used to reproduce the [O~III] / [O~II] / [O~I] / [Ne~III] intensity ratios in central regions of the Orion Nebula. O and Ne have accurate atomic data and can be used to derive an empirical S$^{2+} \\rightarrow$ S$^+$ DR rate coefficient at $\\sim 10^{4}$...

  6. PPAK integral field spectroscopy survey of the Orion nebula. Data release

    Science.gov (United States)

    Sánchez, S. F.; Cardiel, N.; Verheijen, M. A. W.; Martín-Gordón, D.; Vilchez, J. M.; Alves, J.

    2007-04-01

    Aims:We present a low-resolution spectroscopic survey of the Orion nebula. The data are released for public use. We show the possible applications of this dataset analyzing some of the main properties of the nebula. Methods: We perform an integral field spectroscopy mosaic of an area of ~5 arcmin× 6 arcmin centered on the Trapezium region of the nebula, including the ionization front to the south-east. Analysis of the line fluxes and line ratios of both the individual and integrated spectra allowed us to determine the main characteristics of the ionization throughtout the nebula. Results: The final dataset comprises 8182 individual spectra, sampled in a circular area of ~2.7 arcsec diameter. The data can be downloaded as a single row-stacked spectra fit file plus a position table or as an interpolated datacube with a final sampling of 1.5 arcsec/pixel. The integrated spectrum across the field-of-view was used to obtain the main integrated properties of the nebula, including the electron density and temperature, the dust extinction, the Hα integrated flux (after correcting for dust reddening), and the main diagnostic line ratios. The individual spectra were used to obtain line intensity maps of the different detected lines. These maps were used to study the distribution of the ionized hydrogen, the dust extinction, the electron density and temperature, and the helium and oxygen abundance. All of them show a considerable degree of structure as already shown in previous studies. In particular, there is a tight relation between the helium and oxygen abundances and the ionization structure that cannot be explained by case B recombination theory. Simple arguments like partial ionization and dust mixed with the emitting gas may explain these relations. However a more detailed modeling is required, for which we provide the dataset. Based on observations collected at the Centro Astronḿico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut

  7. Structure and physical conditions in the Huygens region of the Orion nebula

    Science.gov (United States)

    O'Dell, C. R.; Ferland, G. J.; Peimbert, M.

    2017-02-01

    Hubble Space Telescope images, MUSE maps of emission lines, and an atlas of high velocity resolution emission-line spectra have been used to establish for the first time correlations of the electron temperature, electron density, radial velocity, turbulence, and orientation within the main ionization front of the nebula. From the study of the combined properties of multiple features, it is established that variations in the radial velocity are primarily caused by the photoevaporating ionization front being viewed at different angles. There is a progressive increase of the electron temperature and density with decreasing distance from the dominant ionizing star θ1 Ori C. The product of these characteristics (ne × Te) is the most relevant parameter in modelling a blister-type nebula like the Huygens region, where this quantity should vary with the surface brightness in Hα. Several lines of evidence indicate that small-scale structure and turbulence exist down to the level of our resolution of a few arcseconds. Although photoevaporative flow must contribute at some level to the well-known non-thermal broadening of the emission lines, comparison of quantitative predictions with the observed optical line widths indicates that it is not the major additive broadening component. Derivation of Te values for H+ from radio+optical and optical-only ionized hydrogen emission showed that this temperature is close to that derived from [N II] and that the transition from the well-known flat extinction curve which applies in the Huygens region to a more normal steep extinction curve occurs immediately outside of the Bright Bar feature of the nebula.

  8. Radio Measurements of the Stellar Proper Motions in the Core of the Orion Nebula Cluster

    Science.gov (United States)

    Dzib, Sergio A.; Loinard, Laurent; Rodríguez, Luis F.; Gómez, Laura; Forbrich, Jan; Menten, Karl M.; Kounkel, Marina A.; Mioduszewski, Amy J.; Hartmann, Lee; Tobin, John J.; Rivera, Juana L.

    2017-01-01

    Using multi-epoch Very Large Array observations, covering a time baseline of 29.1 years, we have measured the proper motions of 88 young stars with compact radio emission in the core of the Orion Nebula Cluster (ONC) and the neighboring BN/KL region. Our work increases the number of young stars with measured proper motion at radio frequencies by a factor of 2.5 and enables us to perform a better statistical analysis of the kinematics of the region than was previously possible. Most stars (79 out of 88) have proper motions consistent with a Gaussian distribution centered on \\overline{{μ }α \\cos δ }=1.07+/- 0.09 mas yr‑1, and \\overline{{μ }δ }=-0.84+/- 0.16 mas yr‑1, with velocity dispersions of {σ }α =1.08+/- 0.07 mas yr‑1, {σ }δ =1.27+/- 0.15 mas yr‑1. We looked for organized movements of these stars but found no clear indication of radial expansion/contraction or rotation. The remaining nine stars in our sample show peculiar proper motions that differ from the mean proper motions of the ONC by more than 3σ. One of these stars, V 1326 Ori, could have been expelled from the Orion Trapezium 7000 years ago. Two could be related to the multi-stellar disintegration in the BN/KL region, in addition to the previously known sources BN, I and n. The others either have high uncertainties (so their anomalous proper motions are not firmly established) or could be foreground objects.

  9. The Kelvin-Helmholtz instability in the Orion nebula: the effect of radiation pressure

    Science.gov (United States)

    Yaghouti, S. Akram; Nejad-Asghar, Mohsen; Abbassi, Shahram

    2017-09-01

    The recent observations of rippled structures on the surface of the Orion molecular cloud (Berné et al. 2010) have been attributed to the Kelvin-Helmholtz (KH) instability. The wavelike structures that have been mainly seen near star-forming regions take place at the interface between the hot diffuse gas, which is ionized by massive stars, and the cold dense molecular clouds. The radiation pressure of massive stars and stellar clusters is one of the important issues that has been considered frequently in the dynamics of clouds. Here, we investigate the influence of radiation pressure, from the well-known Trapezium cluster in the Orion nebula, on the evolution of KH instability. The stability of the interface between the H ii region and the molecular clouds in the presence of radiation pressure has been studied using the linear perturbation analysis for a certain range of wavelengths. The linear analysis shows that the consideration of the radiation pressure intensifies the growth rate of KH modes and consequently decreases the e-fold time-scale of the instability. On the other hand, the domain of the instability is extended and includes more wavelengths, consisting of smaller ones rather than the case where the effect of the radiation pressure is not considered. Our results show that for λKH > 0.15 pc, the growth rate of KH instability does not depend on radiation pressure. Based on our results, the radiation pressure is a triggering mechanism in the development of the KH instability and subsequent formation of turbulent sub-structures in the molecular clouds near massive stars. The role of magnetic fields in the presence of radiation pressure is also investigated and it has resulted in the magnetic field suppressing the effects induced by radiation pressure.

  10. The Population of Compact Radio Sources in the Orion Nebula Cluster

    CERN Document Server

    Forbrich, Jan; Menten, Karl M; Reid, Mark J; Chandler, Claire J; Rau, Urvashi; Bhatnagar, Sanjay; Wolk, Scott J; Meingast, Stefan

    2016-01-01

    We present a deep centimeter-wavelength catalog of the Orion Nebula Cluster (ONC), based on a 30h single-pointing observation with the Karl G. Jansky Very Large Array in its high-resolution A-configuration using two 1 GHz bands centered at 4.7 GHz and 7.3 GHz. A total of 556 compact sources were detected in a map with a nominal rms noise of 3 muJy/bm, limited by complex source structure and the primary beam response. Compared to previous catalogs, our detections increase the sample of known compact radio sources in the ONC by more than a factor of seven. The new data show complex emission on a wide range of spatial scales. Following a preliminary correction for the wideband primary-beam response, we determine radio spectral indices for 170 sources whose index uncertainties are less than +/-0.5. We compare the radio to the X-ray and near-infrared point-source populations, noting similarities and differences.

  11. Thermal Dust Emission from Proplyds, Unresolved Disks, and Shocks in the Orion Nebula

    CERN Document Server

    Smith, N; Shuping, R Y; Morris, M; Kassis, M; Smith, Nathan; Bally, John; Shuping, Ralph Y.; Morris, Mark; Kassis, Marc

    2005-01-01

    We present a new 11.7 micron mosaic image of the Orion nebula obtained with T-ReCS on Gemini South. The map includes the BN/KL region, the Trapezium, and OMC-1 South. Excluding BN/KL, we detect 91 point sources, with 27 known proplyds and over 30 ``naked'' stars showing no extended structure in HST images. Within the region we surveyed, 80 percent of known proplyds show detectable emission, almost 40 percent of naked stars are detected at 11.7 micron, and the fraction of all visible sources with IR excess emission is roughly 50 percent. Thermal dust emission from stars with no extended structure in HST images means that they have dust disks comparable to the size of our solar system. Proplyds and stars with IR excess show a clear anti-correlation in their spatial distribution, with proplyds clustered close to theta1C, and other infrared sources found farther away. We suspect that the clustered proplyds trace the youngest 0.5 Myr age group associated with the Trapezium, while the more uniformly-distributed sou...

  12. Kinematics of the Orion Nebula Cluster: Velocity Substructure and Spectroscopic Binaries

    CERN Document Server

    Tobin, J J; Furesz, G; Mateo, M; Megeath, S T

    2009-01-01

    We present a kinematic study of the Orion Nebula Cluster based upon radial velocities measured by multi-fiber echelle spectroscopy at the 6.5 meter MMT and Magellan telescopes. Velocities are reported for 1613 stars, with multi-epoch data for 727 objects as part of our continuing effort to detect and analyze spectroscopic binaries. We confirm and extend the results of Furesz et al. showing that the ONC is not relaxed, consistent with its youth, and that the stars generally follow the position-velocity structure of the moderate density gas in the region, traced by $^{13}$CO. The additional radial velocities we have measured enable us to probe some discrepancies between stellar and gaseous structure which can be attributed to binary motion and the inclusion of non-members in our kinematic sample. Our multi-epoch data allow us to identify 89 spectroscopic binaries; more will be found as we continue monitoring. Our results reinforce the idea that the ONC is a cluster in formation, and thus provides a valuable tes...

  13. A Multi-Color Optical Survey of the Orion Nebula Cluster. Part I: the Catalog

    CERN Document Server

    Da Rio, Nicola; Soderblom, David R; Panagia, Nino; Hillenbrand, Lynne A; Palla, Francesco; Stassun, Keivan

    2009-01-01

    We present U, B, V, I broad-band, 6200A TiO medium-band and Halpha photometry of the Orion Nebula Cluster obtained with the WFI imager at the ESO/MPI 2.2 telescope. The nearly-simultaneous observations cover the entire ONC in a field of about 34x34 arcmin. They enable us to determine stellar colors avoiding the additional scatter in the photometry induced by stellar variability typical of pre-main sequence stars. We identify 2,612 point-like sources in I band, 58%, 43% and 17% of them detected also in V, B and U, respectively. 1040 sources are identified in Halpha band. In this paper we present the observations, the calibration techniques, and the resulting catalog. We show the derived CMD of the population and discuss the completeness of our photometry. We define a spectro-photometric TiO index from the fluxes in V, I, and TiO-band. We find a correlation between the index and the spectral type valid for M-type stars, that is accurate to better than 1 spectral sub-class for M3-M6 types and better than 2 spect...

  14. Photospheric Spot Temperature Models of Young Stars in the Orion Nebula Cluster

    Science.gov (United States)

    Miller, M. J.; Stassun, K. G.; Jensen, E. L. N.

    2003-12-01

    We apply a simple photospheric spot temperature model to photometric variability measurements of T Tauri stars in the Trapezium region of the Orion Nebula Cluster. Our aim is to search for the relationship, if any, between spot temperatures and stellar rotation periods to better understand the relationship between accretion and angular momentum regulation in T Tauri stars. Current magnetic disk-locking models of young stars ascribe spot temperatures hotter than the photosphere to signatures of active accretion from a circumstellar disk. If accretion acts to brake stellar rotation, spot temperatures hotter than the photosphere should be more prevalent among slow rotators. From the variability amplitudes at four wavelengths (B, V, R, I), we determine spot temperatures and the areal coverage of the spot on the stellar surface. The results of our model show that we can unambiguously distinguish spots hotter than the photosphere from spots cooler than the photosphere for most stars. We present the results of our search for correlations between spot temperatures and previously determined rotation periods.

  15. Photoevaporation Flows in Blister HII Regions: I. Smooth Ionization Fronts and Application to the Orion Nebula

    CERN Document Server

    Henney, W J; Garcia-Diaz, M T; Garcia-Diaz, Ma. T.

    2005-01-01

    We present hydrodynamical simulations of the photoevaporation of a cloud with large-scale density gradients, giving rise to an ionized, photoevaporation flow. The flow is found to be approximately steady during the large part of its evolution, during which it can resemble a "champagne flow" or a "globule flow" depending on the curvature of the ionization front. The distance from source to ionization front and the front curvature uniquely determine the structure of the flow, with the curvature depending on the steepness of the lateral density gradient in the neutral cloud. We compare these simulations with both new and existing observations of the Orion nebula and find that a model with a mildly convex ionization front can reproduce the profiles of emission measure, electron density, and mean line velocity for a variety of emitting ions on scales of 10^{17} to 10^{18} cm. The principal failure of our model is that we cannot explain the large observed widths of the [O I] 6300 Angstrom line that forms at the ion...

  16. Quantitative evidence of an intrinsic luminosity spread in the Orion nebula cluster

    Science.gov (United States)

    Reggiani, M.; Robberto, M.; Da Rio, N.; Meyer, M. R.; Soderblom, D. R.; Ricci, L.

    2011-10-01

    Aims: We study the distribution of stellar ages in the Orion nebula cluster (ONC) using accurate HST photometry taken from HST Treasury Program observations of the ONC utilizing the cluster distance estimated by Menten and collaborators. We investigate whether there is an intrinsic age spread in the region and whether the age depends on the spatial distribution. Methods: We estimate the extinction and accretion luminosity towards each source by performing synthetic photometry on an empirical calibration of atmospheric models using the package Chorizos of Maiz-Apellaniz. The position of the sources in the HR-diagram is compared with different theoretical isochrones to estimate the mean cluster age and age dispersion. On the basis of Monte Carlo simulations, we quantify the amount of intrinsic age spread in the region, taking into account uncertainties in the distance, spectral type, extinction, unresolved binaries, accretion, and photometric variability. Results: According to the evolutionary models of Siess and collaborators, the mean age of the Cluster is 2.2 Myr with a scatter of few Myr. With Monte Carlo simulations, we find that the observed age spread is inconsistent with that of a coeval stellar population, but in agreement with a star formation activity between 1.5 and 3.5 Myr. We also observe some evidence that ages depends on the spatial distribution.

  17. Radio Measurements of the stellar proper motions in the core of the Orion Nebula Cluster

    CERN Document Server

    Dzib, Sergio A; Rodríguez, Luis F; Gómez, Laura; Forbrich, Jan; Menten, Karl M; Kounkel, Marina A; Mioduszewski, Amy J; Hartmann, Lee; Tobin, John J; Rivera, Juana L

    2016-01-01

    Using multi-epoch VLA observations, covering a time baseline of 29.1 years, we have measured the proper motions of 88 young stars with compact radio emission in the core of the Orion Nebula Cluster (ONC) and the neighboring BN/KL region. Our work increases the number of young stars with measured proper motion at radio frequencies by a factor of 2.5 and enables us to perform a better statistical analysis of the kinematics of the region than was previously possible. Most stars (79 out of 88) have proper motions consistent with a Gaussian distribution centered on $\\overline{\\mu_{\\alpha}\\cos{\\delta}}=1.07\\pm0.09\\quad{\\rm mas\\,yr^{-1}}$, and $\\overline{\\mu_{\\delta}}=-0.84\\pm0.16\\quad{\\rm mas\\,yr^{-1}}$, with velocity dispersions of $\\sigma_{\\alpha}=1.08\\pm0.07\\quad{\\rm mas\\,\\,yr^{-1}},$ $\\sigma_{\\delta}=1.27\\pm0.15\\quad{\\rm mas\\,\\,yr^{-1}}$. We looked for organized movements of these stars but found no clear indication of radial expansion/contraction or rotation. The remaining nine stars in our sample show peculia...

  18. HST measures of Mass Accretion Rates in the Orion Nebula Cluster

    CERN Document Server

    Manara, C F; Da Rio, N; Lodato, G; Hillenbrand, L A; Stassun, K G; Soderblom, D R

    2012-01-01

    The present observational understanding of the evolution of the mass accretion rates (Macc) in pre-main sequence stars is limited by the lack of accurate measurements of Macc over homogeneous and large statistical samples of young stars. Such observational effort is needed to properly constrain the theory of star formation and disk evolution. Based on HST/WFPC2 observations, we present a study of Macc for a sample of \\sim 700 sources in the Orion Nebula Cluster, ranging from the Hydrogen-burning limit to M\\ast \\sim 2M\\odot. We derive Macc from both the U-band excess and the H{\\alpha} luminosity (LH{\\alpha}), after determining empirically both the shape of the typical accretion spectrum across the Balmer jump and the relation between the accretion luminosity (Lacc) and LH{\\alpha}, that is Lacc/L\\odot = (1.31\\pm0.03)\\cdotLH{\\alpha}/L\\odot + (2.63\\pm 0.13). Given our large statistical sample, we are able to accurately investigate relations between Macc and the parameters of the central star such as mass and age....

  19. Identification of New Near-Infrared Diffuse Interstellar Bands in the Orion Nebula

    Science.gov (United States)

    Misawa, Toru; Gandhi, Poshak; Hida, Akira; Tamagawa, Toru; Yamaguchi, Tomohiro

    2009-08-01

    Large organic molecules and carbon clusters are basic building blocks of life, but their existence in the universe has not been confirmed beyond doubt. A number of unidentified absorption features (arising in the diffuse interstellar medium), usually called "Diffuse Interstellar Bands" (DIBs), are hypothesized to be produced by large molecules. Among these, buckminsterfullerene C60 has gained much attention as a candidate for DIB absorbers because of its high stability in space. Two DIBs at λ ~ 9577 Å and 9632 Å have been reported as possible features of C+ 60. However, it is still not clear how their existence depends on their environment. We obtained high-resolution spectra of three stars in/around the Orion Nebula, to search for any correlations of the DIB strength with carrier's physical conditions, such as dust abundance and UV radiation field. We find three DIBs at λ ~ 9017 Å, 9210 Å, and 9258 Å as additional C+ 60 feature candidates, which could support this identification. These DIBs have asymmetric profiles similar to the longer wavelength features. However, we also find that the relative strengths of DIBs are close to unity and differ from laboratory measurements, a similar trend as noticed for the 9577/9632 DIBs. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  20. Identification of New Near-Infrared DIBs in the Orion Nebula

    CERN Document Server

    Misawa, Toru; Hida, Akira; Tamagawa, Toru; Yamaguchi, Tomohiro

    2009-01-01

    Large organic molecules and carbon clusters are basic building blocks of life, but their existence in the universe has not been confirmed beyond doubt. A number of unidentified absorption features (arising in the diffuse inter-stellar medium), usually called ``Diffuse Inter-stellar Bands (DIBs)'', are hypothesized to be produced by large molecules. Among these, buckminsterfullerene C_60 has gained much attention as a candidate for DIB absorbers because of its high stability in space. Two DIBs at ~9577A and 9632A have been reported as possible features of C_60^+. However, it is still not clear how their existence depends on their environment. We obtained high-resolution spectra of three stars in/around the Orion Nebula, to search for any correlations of the DIB strength with carrier's physical conditions, such as dust-abundance and UV radiation field. We find three DIBs at ~9017A, 9210A, and 9258A as additional C_60^+ feature candidates, which could support this identification. These DIBs have asymmetric profi...

  1. Rotational studies in the Orion Nebula Cluster: from solar mass stars to brown dwarfs

    CERN Document Server

    Rodriguez-Ledesma, Maria Victoria; Eislöffel, Jochen

    2009-01-01

    Rotational studies at a variety of ages and masses are important for constraining the angular momentum evolution of young stellar objects (YSO). Of particular interest are the very low mass (VLM) stars and brown dwarfs (BDs), because of the significant lack of known rotational periods in that mass range. We provide for the first time information on rotational periods for a large sample of young VLM stars and BDs. This extensive rotational period study in the 1 Myr old Orion Nebula Cluster (ONC) is based on a deep photometric monitoring campaign using the Wide Field Imager (WFI) camera on the ESO/MPG 2.2m telescope on La Silla, Chile. Accurate I-band photometry of 2908 stars was obtained, extending three magnitudes deeper than previous studies in the ONC. We found 487 periodic variables with estimated masses between 0.5 Msun and 0.015 Msun, 124 of which are BD candidates. This is by far the most extensive and complete rotational period data set for young VLM stars and BDs. In addition, 808 objects show non-per...

  2. A VLA Survey for Faint Compact Radio Sources in the Orion Nebula Cluster

    Science.gov (United States)

    Sheehan, Patrick D.; Eisner, Josh A.; Mann, Rita K.; Williams, Jonathan P.

    2016-11-01

    We present Karl G. Jansky Very Large Array 1.3, 3.6, and 6 cm continuum maps of compact radio sources in the Orion Nebular Cluster (ONC). We mosaicked 34 arcmin2 at 1.3 cm, 70 arcmin2 at 3.6 cm and 109 arcmin2 at 6 cm, containing 778 near-infrared detected young stellar objects and 190 Hubble Space Telescope-identified proplyds (with significant overlap between those characterizations). We detected radio emission from 175 compact radio sources in the ONC, including 26 sources that were detected for the first time at these wavelengths. For each detected source, we fitted a simple free-free and dust emission model to characterize the radio emission. We extrapolate the free-free emission spectrum model for each source to ALMA bands to illustrate how these measurements could be used to correctly measure protoplanetary disk dust masses from submillimeter flux measurements. Finally, we compare the fluxes measured in this survey with previously measured fluxes for our targets, as well as four separate epochs of 1.3 cm data, to search for and quantify the variability of our sources.

  3. H2 Velocity Maps of Orion: Destruction of the Environment of the BN-KL Nebula

    Directory of Open Access Journals (Sweden)

    Luis Salas

    2001-01-01

    Full Text Available We present the velocity structure of the 2.12 micron H2 emission in Orion, obtained with an IR Fabry-Perot interferometer with a spectral resolution of 24 km/s and a 2arcsec spatial resolution, covering a region of 3.6´ by 3.6´ (0.46 by 0.46 pc2 that contains the H2 filamentary finger system. A simple model is proposed to explain the observed low velocity structure as described by its radial moments: intensity, velocity centroid, velocity dispersion and skewness. We assume a strong wind of 230 km/s produced by IRc2 interacting with a set of molecular clumps with density of 5.6×105 cm-3. The scenario provides a good match to the observed moments is obtained, gives clues to the development of filaments or fingers and entrainment of the molecular material, and associates the observed high velocity blueshifted emission to the region. The H2 line emission is produced by a slow J-shock (20 km/s in the clumps with an emissivity proportional to v1.8 . Estimates for the total wind mass and clumps mass yield 0.5 Msolar and 15 Msolar inside a radius of 1arcmin (0.1 pc. The individual clumps have masses and sizes of few × 10-3 Msolar and 0.007 pc, respectively. We conclude that the central 0.1 pc region surrounding the BN-KL nebula in front of OMC-1 is in the process of being disrupted by the strong wind of IRc2 on a time scale of 2000 yr.

  4. A NEW Hα EMISSION-LINE SURVEY IN THE ORION NEBULA CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Szegedi-Elek, E.; Kun, M.; Pál, A.; Balázs, L. G. [Konkoly Observatory, H-1121 Budapest, Konkoly Thege út 15-17 (Hungary); Reipurth, B.; Willman, M., E-mail: eelza@konkoly.hu [Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, Hilo, HI 96720 (United States)

    2013-10-01

    We present results from an Hα emission line survey in a 1 deg{sup 2} area centered on the Orion Nebula Cluster, obtained with the Wide Field Grism Spectrograph 2 on the 2.2 m telescope of the University of Hawaii. We identified 587 stars with Hα emission, 99 of which, located mainly in the outer regions of the observed area, have not appeared in previous Hα surveys. We determined the equivalent width (EW) of the line and, based on this, classified 372 stars as classical T Tauri stars (CTTSs) and 187 as weak-line T Tauri stars (WTTSs). Simultaneous r', i' photometry indicates a limiting magnitude of r' ∼ 20 mag, but the sample is incomplete at r' > 17 mag. The surface distribution of the Hα emission stars reveals a clustered population and a dispersed population, the former consisting of younger and more massive young stars than the latter. Comparison of the derived EWs with those found in the literature indicates variability of the Hα line. We found that the typical amplitudes of the variability are not greater than a factor of two to three in most cases. We identified a subgroup of low-EW stars with infrared signatures indicative of optically thick accretion disks. We studied the correlations between the EW and other properties of the stars. Based on literature data, we examined several properties of our CTTS and WTTS subsamples and found significant differences in mid-infrared color indices, average rotational periods, and spectral energy distribution characteristics of the subsamples.

  5. YSOVAR: SIX PRE-MAIN-SEQUENCE ECLIPSING BINARIES IN THE ORION NEBULA CLUSTER

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Calderon, M.; Stauffer, J. R.; Rebull, L. M. [Spitzer Science Center, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125 (United States); Stassun, K. G. [Physics and Astronomy Department, Vanderbilt University, 1807 Station B, Nashville, TN 37235 (United States); Vrba, F. J. [U. S. Naval Observatory, Flagstaff Station, 10391 W. Naval Observatory Road, Flagstaff, AZ 86001-8521 (United States); Prato, L. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Hillenbrand, L. A.; Carpenter, J. M. [Astronomy Department, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125 (United States); Terebey, S.; Angione, J. [Department of Physics and Astronomy, California State University at Los Angeles, Los Angeles, CA 90032 (United States); Covey, K. R. [Department of Astronomy, Cornell University, 226 Space Sciences Building, Ithaca, NY 14853 (United States); Terndrup, D. M. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Gutermuth, R. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Song, I. [Physics and Astronomy Department, University of Georgia, Athens, GA 30602-2451 (United States); Plavchan, P. [NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States); Marchis, F. [SETI Institute, Carl Sagan Center, 189 N San Bernado Av, Mountain View, CA 94043 (United States); Garcia, E. V. [Department of Physics, Fisk University, 1000 17th Ave. N, Nashville, TN 37208 (United States); Margheim, S. [Gemini Observatory, Southern Operations Center, Casilla 603, La Serena (Chile); Luhman, K. L. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Irwin, J. M., E-mail: mariamc@cab.inta-csic.es [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)

    2012-07-10

    Eclipsing binaries (EBs) provide critical laboratories for empirically testing predictions of theoretical models of stellar structure and evolution. Pre-main-sequence (PMS) EBs are particularly valuable, both due to their rarity and the highly dynamic nature of PMS evolution, such that a dense grid of PMS EBs is required to properly calibrate theoretical PMS models. Analyzing multi-epoch, multi-color light curves for {approx}2400 candidate Orion Nebula Cluster (ONC) members from our Warm Spitzer Exploration Science Program YSOVAR, we have identified 12 stars whose light curves show eclipse features. Four of these 12 EBs are previously known. Supplementing our light curves with follow-up optical and near-infrared spectroscopy, we establish two of the candidates as likely field EBs lying behind the ONC. We confirm the remaining six candidate systems, however, as newly identified ONC PMS EBs. These systems increase the number of known PMS EBs by over 50% and include the highest mass ({theta}{sup 1} Ori E, for which we provide a complete set of well-determined parameters including component masses of 2.807 and 2.797 M{sub Sun }) and longest-period (ISOY J053505.71-052354.1, P {approx} 20 days) PMS EBs currently known. In two cases ({theta}{sup 1} Ori E and ISOY J053526.88-044730.7), enough photometric and spectroscopic data exist to attempt an orbit solution and derive the system parameters. For the remaining systems, we combine our data with literature information to provide a preliminary characterization sufficient to guide follow-up investigations of these rare, benchmark systems.

  6. Panchromatic Hubble Andromeda Treasury IX: A Photometric Survey of Planetary Nebulae in M31

    CERN Document Server

    Veyette, Mark J; Dalcanton, Julianne J; Balick, Bruce; Caldwell, Nelson; Fouesneau, Morgan; Girardi, Leo; Gordon, Karl; Kalirai, Jason; Rosenfield, Phil; Seth, Anil

    2014-01-01

    We search Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) broadband imaging data from the Panchromatic Hubble Andromeda Treasury (PHAT) survey to identify detections of cataloged planetary nebulae (PNe). Of the 711 PNe currently in the literature within the PHAT footprint, we find 467 detected in the broadband. For these 467 we are able to refine their astrometric accuracy from ~0."3 to 0."05. Using the resolution of HST, we are able to show that 152 objects currently in the catalogs are definitively not PNe, and we show that 32 objects thought to be extended in ground-based images are actually point-like and therefore good PN candidates. We also find one PN candidate that is marginally resolved. If this is a PN, it is up to 0.7 pc in diameter. With our new photometric data, we develop a method of measuring the level of excitation in individual PNe by comparing broadband and narrowband imaging and describe the effects of excitation on a PN's photometric signature....

  7. Panchromatic Hubble Andromeda Treasury. IX. A photometric survey of planetary nebulae in M31

    Energy Technology Data Exchange (ETDEWEB)

    Veyette, Mark J.; Williams, Benjamin F.; Dalcanton, Julianne J.; Balick, Bruce; Fouesneau, Morgan [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Girardi, Léo [Osservatorio Astronomico di Padova—INAF, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Gordon, Karl D.; Kalirai, Jason [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Rosenfield, Philip [Department of Physics and Astronomy G. Galilei, University of Padova, Vicolo dell' Osservatorio 3, I-35122 Padova (Italy); Seth, Anil C., E-mail: mveyette@uw.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States)

    2014-09-10

    We search the Hubble Space Telescope (HST) Advanced Camera for Surveys and Wide Field Camera 3 broadband imaging data from the Panchromatic Hubble Andromeda Treasury (PHAT) survey to identify detections of cataloged planetary nebulae (PNs). Of the 711 PNs currently in the literature within the PHAT footprint, we find 467 detected in the broadband. For these 467, we are able to refine their astrometric accuracy from ∼0.''3 to 0.''05. Using the resolution of the HST, we are able to show that 152 objects currently in the catalogs are definitively not PNs, and we show that 32 objects thought to be extended in ground-based images are actually point-like and therefore good PN candidates. We also find one PN candidate that is marginally resolved. If this is a PN, it is up to 0.7 pc in diameter. With our new photometric data, we develop a method of measuring the level of excitation in individual PNs by comparing broadband and narrowband imaging and describe the effects of excitation on a PN's photometric signature. Using the photometric properties of the known PNs in the PHAT catalogs, we search for more PNs, but do not find any new candidates, suggesting that ground-based emission-line surveys are complete in the PHAT footprint to F475W ≅ 24.

  8. First Science Observations with SOFIA/FORCAST: 6 to 37 micron Imaging of the Central Orion Nebula

    CERN Document Server

    Shuping, R Y; Herter, Terry L; Adams, Joseph D; Gull, G E; Schoenwald, J; Henderson, C P; Becklin, E E; De Buizer, James M; Vacca, William D; Zinnecker, Hans; Megeath, S Thomas

    2012-01-01

    We present new mid-infrared images of the central region of the Orion Nebula using the newly commissioned SOFIA airborne telescope and its 5 -- 40 micron camera FORCAST. The 37.1 micron images represent the highest resolution observations (<4") ever obtained of this region at these wavelengths. After BN/KL (which is described in a separate letter in this issue), the dominant source at all wavelengths except 37.1 micron is the Ney-Allen Nebula, a crescent-shaped extended source associated with theta 1D. The morphology of the Ney-Allen nebula in our images is consistent with the interpretation that it is ambient dust swept up by the stellar wind from theta 1D, as suggested by Smith et al. (2005). Our observations also reveal emission from two "proplyds" (proto-planetary disks), and a few embedded young stellar objects (YSOs; IRc9, and OMC1S IRS1, 2, and 10). The spectral energy distribution for IRc9 is presented and fitted with standard YSO models from Robitaille et al. (2007) to constrain the total luminosi...

  9. Protoplanetary Disks in the Orion Nebula An H$\\alpha$ Fabry-Perot study and Astrobiological Aspects

    CERN Document Server

    De la Fuente-Acosta, E; Arias, L; Throop, H B; Ambrocio-Cruz, P; Fuente, Eduardo de la; Rosado, Margarita; Arias, Lorena; Throop, Patricia Ambrocio-Cruz & Henry B.

    2002-01-01

    In this paper, we present a briefly overview of the protoplanetary disks in the Orion Nebula, incluiding some astrobiological aspects and an H$\\alpha$ Fabry-Perot study of 16 of them. We found that Fabry-Perot interferometry constitutes an effective technique for the detection of proplyds. We also report heliocentric systemic velocities for the proplyds 82-336, 158-323, 158-326, 159-350, 161-314, 161-324, 163-317, 166-316, 167-317, 168-326, 170-337, 176-325, 177-341, 180-331, 197-427 and 244-440. The velocities were measured between 22-38 km s$^{-1}$.

  10. ALMA Observations of the Largest Proto-Planetary Disk in the Orion Nebula, 114-426: A CO Silhouette

    CERN Document Server

    Bally, John; Eisner, Josh; Andrews, Sean M; Di Francesco, James; Hughes, Meredith; Johnstone, Doug; Matthews, Brenda; Ricci, Luca; Williams, Jonathan P

    2015-01-01

    We present ALMA observations of the largest protoplanetary disk in the Orion Nebula, 114-426. Detectable 345 GHz (856 micron) dust continuum is produced only in the 350 AU central region of the ~1000 AU diameter silhouette seen against the bright H-alpha background in HST images. Assuming optically thin dust emission at 345 GHz, a gas-to-dust ratio of 100, and a grain temperature of 20 K, the disk gas-mass is estimated to be 3.1 +/- 0.6 Jupiter masses. If most solids and ices have have been incorporated into large grains, however, this value is a lower limit. The disk is not detected in dense-gas tracers such as HCO+ J=4-3, HCN J=4-3, or CS =7-6. These results may indicate that the 114-426 disk is evolved and depleted in some light organic compounds found in molecular clouds. The CO J=3-2 line is seen in absorption against the bright 50 to 80 K background of the Orion A molecular cloud over the full spatial extent and a little beyond the dust continuum emission. The CO absorption reaches a depth of 27 K below...

  11. Short- and long-term variability of young stars in the Orion Nebula Cluster and Molecular Cloud

    CERN Document Server

    Rivilla, V M; Sanz-Forcada, J; Jiménez-Serra, I; Forbrich, J; Martín-Pintado, J

    2015-01-01

    We used the Very Large Array to carry out a multi-epoch radio continuum monitoring of the Orion Nebula Cluster and Orion Molecular Cloud. Our observations reveal the presence of 19 sources. With the exception of the sources BN and C the sources show variability between the different epochs. We have found tentative evidence of variability in the massive object related with source I. Our observations also confirm radio flux density variations of a factor >2 on timescales of hours to days in 5 sources. One of these flaring sources, OHC-E, has been detected for the first time. We conclude that the radio emission arises from: i) highly-variable non-thermal gyrosynchrotron emission produced by electrons accelerated in the magnetospheres of pre-main sequence stars; ii) thermal emission from ionized gas and/or heated dust around massive objects and proplyds. Combining our sample with other radio monitoring and a X-ray catalog, we have studied the properties of 51 radio/X-ray stars. We have found severals hints of a d...

  12. FIRST SCIENCE OBSERVATIONS WITH SOFIA/FORCAST: 6-37 {mu}m IMAGING OF THE CENTRAL ORION NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Shuping, R. Y. [Space Science Institute, 4750 Walnut St., Suite 205, Boulder, CO 80301 (United States); Morris, Mark R. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Herter, Terry L.; Adams, Joseph D.; Gull, G. E.; Schoenwald, J.; Henderson, C. P. [Center for Radiophysics and Space Research, Cornell University, 208 Space Sciences Building, Ithaca, NY 14853 (United States); Becklin, E. E.; De Buizer, James M.; Vacca, William D.; Zinnecker, Hans [SOFIA-USRA, NASA Ames Research Center, MS N211-3, Moffett Field, CA 94035 (United States); Thomas Megeath, S., E-mail: rshuping@spacescience.org [Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft St., Toledo, OH 43606 (United States)

    2012-04-20

    We present new mid-infrared images of the central region of the Orion Nebula using the newly commissioned Stratospheric Observatory For Infrared Astronomy airborne telescope and its 5-40 {mu}m camera FORCAST. The 37.1 {mu}m images represent the highest resolution observations ({approx}<4'') ever obtained of this region at these wavelengths. After BN/KL (which is described in a separate paper in this issue), the dominant source at all wavelengths except 37.1 {mu}m is the Ney-Allen Nebula, a crescent-shaped extended source associated with {theta}{sup 1} D Ori. The morphology of the Ney-Allen nebula in our images is consistent with the interpretation that it is ambient dust swept up by the stellar wind from {theta}{sup 1} D Ori, as suggested by Smith et al. in 2005. Our observations also reveal emission from two 'proplyds' (proto-planetary disks), and a few embedded young stellar objects (YSOs; IRc 9, and OMC1-S IRS1, 2, and 10). The spectral energy distribution for IRc 9 is presented and fitted with standard YSO models from Robitaille et al. in 2007 to constrain the total luminosity, disk size, and envelope size. The diffuse, nebular emission we observe at all FORCAST wavelengths is most likely from the background photodissociation region (PDR) and shows structure that coincides roughly with H{alpha} and [N II] emission. We conclude that the spatial variations in the diffuse emission are likely due to undulations in the surface of the background PDR.

  13. Imaging of four planetary nebulae in the Magellanic Clouds using the Hubble Space Telescope Faint Object Camera

    Science.gov (United States)

    Blades, J. C.; Barlow, M. J.; Albrecht, R.; Barbieri, C.; Boksenberg, A.; Crane, P.; Deharveng, J. M.; Disney, M. J.; Jakobsen, P.; Kamperman, T. M.

    1992-01-01

    Using the Faint Object Camera on-board the Hubble Space Telescope, we have obtained images of four planetary nebulae (PNe) in the Magellanic Clouds, namely N2 and N5 in the SMC and N66 and N201 in the LMC. Each nebula was imaged through two narrow-band filters isolating forbidden O III 5007 and H-beta, for a nominal exposure time of 1000 s in each filter. In forbidden O III, SMC N5 shows a circular ring structure, with a peak-to-peak diameter of 0.26 arcsec and a FWHM of 0.35 arcsec while SMC N2 shows an elliptical ring structure with a peak-to-peak diameter of 0.26 x 0.21. The expansion ages corresponding to the observed structures in SMC N2 and N5 are of the order of 3000 yr. LMC N201 is very compact, with a FWHM of 0.2 arcsec in H-beta. The Type I PN LMC N66 is a multipolar nebula, with the brightest part having an extent of about 2 arcsec and with fainter structures extending over 4 arcsec.

  14. Impact of photometric variability on age and mass determination in young stellar objects: the case of the Orion Nebula Cluster

    Science.gov (United States)

    Messina, Sergio; Parihar, Padmakar; Distefano, Elisa

    2017-03-01

    Very young stars, like the Orion Nebula Cluster (ONC) members analysed in the present study, exhibit photometric variability with a wide range of amplitudes. Such a prominent variability reflects in the inferred values of stellar colours and luminosities and, in turn, in the inferred stellar ages and masses. In this study, we measure the amplitudes of the photometric variability in V, R and I optical bands of a sample of 346 ONC members. We use these measurements to investigate how this variability affects the inferred masses and ages and whether it alone can account for the age spread among ONC members reported by earlier studies. We make use of colour-magnitude and Hertzprung-Russell (HR) diagrams. We find that members that show periodic and smooth photometric rotational modulation have masses and ages that are unaffected by variability when theoretical isochrones and evolutionary mass tracks are used in either colour-magnitude or HR diagrams. On the other hand, members with periodic but very scattered photometric rotational modulation and non-periodic members have masses and ages that are significantly affected. Moreover, using HR diagrams, we find that the observed I-band photometric variability can take account of only a fraction (˜50 per cent) of the inferred age spread, whereas the V-band photometric variability is large enough to mask any age spread.

  15. Structure and Physical Conditions in the Huygens Region of the Orion Nebula

    CERN Document Server

    O'Dell, C R; Peimbert, M

    2016-01-01

    HST images, MUSE maps of emission-lines, and an atlas of high velocity resolution emission-line spectra have been used to establish for the firrst time correlations of the electron temperature, electron density, radial velocity, turbulence, and orientation within the main ionization front of the nebula. From the study of the combined properties of multiple features, it is established that variations in the radial velocity are primarily caused by the photo-evaporating ionization front being viewed at different angles. There is a progressive increase of the electron temperature and density with decreasing distance from the dominant ionizing star Theta1 Ori C. The product of these characteristics (NexTe) is the most relevant parameter in modeling a blister-type nebula like the Huygens Region, where this quantity should vary with the surface brightness in Halpha. Several lines of evidence indicate that small-scale structure and turbulence exists down to the level of our resolution of a few arcseconds. Although ph...

  16. HUBBLE SPACE TELESCOPE Images of the Compact Nebula around RY Scuti

    Science.gov (United States)

    Smith, Nathan; Gehrz, Robert D.; Humphreys, Roberta M.; Davidson, Kris; Jones, Terry J.; Krautter, Joachim

    1999-08-01

    We present HST Wide Field Planetary Camera 2 images of the very massive eclipsing binary RY Scuti. The HST Hα image shows a very complex ionized nebula roughly 1" in size. Several interesting structures are revealed, including what appears to be a pair of concentric ionized rings above and below the equatorial plane of the system, located at the inner edge of a more extended dust torus. We reexamine some essential physical characteristics of the nebula, such as a possible magnetic field and the complicated mass-loss geometry of this near-Eddington limit contact binary. The effects of a rotating illumination source are considered to explain the brightness distribution in the rings. We suggest a model for the origin of the mass and detailed structure in the nebula. This model invokes a previous mass ejection that is shaped by nonspherical interacting winds and possibly magnetic fields.

  17. A VLA Survey For Faint Compact Radio Sources in the Orion Nebula Cluster

    CERN Document Server

    Sheehan, Patrick D; Mann, Rita K; Williams, Jonathan P

    2016-01-01

    We present Karl G. Janksy Very Large Array (VLA) 1.3 cm, 3.6 cm, and 6 cm continuum maps of compact radio sources in the Orion Nebular Cluster. We mosaicked 34 square arcminutes at 1.3 cm, 70 square arcminutes at 3.6 cm and 109 square arcminutes at 6 cm, containing 778 near-infrared detected YSOs and 190 HST-identified proplyds (with significant overlap between those characterizations). We detected radio emission from 175 compact radio sources in the ONC, including 26 sources that were detected for the first time at these wavelengths. For each detected source we fit a simple free-free and dust emission model to characterize the radio emission. We extrapolate the free-free emission spectrum model for each source to ALMA bands to illustrate how these measurements could be used to correctly measure protoplanetary disk dust masses from sub-millimeter flux measurements. Finally, we compare the fluxes measured in this survey with previously measured fluxes for our targets, as well as four separate epochs of 1.3 cm ...

  18. Photoevaporation of Disks and Clumps by Nearby Massive Stars: Application to Disk Destruction in the Orion Nebula

    Science.gov (United States)

    Johnstone, Doug; Hollenbach, David; Bally, John

    1998-05-01

    We present a model for the photoevaporation of circumstellar disks or dense clumps of gas by an external source of ultraviolet radiation. Our model includes the thermal and dynamic effects of 6-13.6 eV far-ultraviolet (FUV) photons and Lyman continuum EUV photons incident upon disks or clumps idealized as spheres of radius rd and enclosed mass M*. For sufficiently large values of rd/M*, the radiation field evaporates the surface gas and dust. Analytical and numerical approximations to the resulting flows are presented; the model depends on rd, M*, the flux of FUV and EUV photons, and the column density of neutral gas heated by FUV photons to high temperatures. Application of this model shows that the circumstellar disks (rd ~ 1014-1015 cm) in the Orion Nebula (``proplyds'') are rapidly destroyed by the external UV radiation field. Close (d Gas evaporated from the cold disk moves subsonically through a relatively thin photodissociation region (PDR) dominated by FUV photons and heated to ~1000 K. As the distance from θ1 Ori C increases, the Lyman continuum flux declines, the PDR thickens, and the IF moves away from the disk surface. At d ~ 3 × 1017 cm, the thickness of the PDR becomes comparable to the disk radius. Between 3 × 1017 cm gas moves subsonically through a stationary D-type IF. The IF is moved away from the disk surface to a standoff distance rIF >~ 2.5rd. In this regime, the mass-loss rate is determined by the incident FUV photon flux and not the ionizing flux. However, at very large distances, d >~ 1018 cm, the FUV photon flux drops to values that cannot maintain the disk surface temperature at ~103 K. As the PDR temperature drops, the pressure of the FUV-powered flow declines with increasing distance from θ1 Ori C, and again the EUV ionizing photons can penetrate close to the disk surface and dominate the evaporation rate. Radio, Hα, and [O III] observations of externally illuminated young stellar objects in the Trapezium region are used to

  19. Physical parameters and long-term photometric variability of V1481 Ori, a SB2 member of Orion Nebula Cluster with an accreting component

    CERN Document Server

    Messina, Sergio; Biazzo, Katia; Lanza, Antonino F; Distefano, Elisa; Melo, Claudio H F; Bradstreet, David; Herbst, William

    2015-01-01

    We present the results of our analysis on V1481 Ori (JW 239), a young SB2 in the Orion Nebula Cluster with a circumbinary disc accreting on the lower-mass component. The analysis is based on high-resolution spectroscopic data and high-quality photometric time series about 20-yr long. Thanks to the spectroscopy, we confirm the binary nature of this system consisting of M3 + M4 components and derive the mass ratio M_B/M_A = 0.54, a variable luminosity ratio L_B/L_A = 0.68--0.94, and an orbital period P_orb = 4.433d. The photometric data allowed us to measure the rotation periods of the two components P_phot = 4.4351d and they are found to be synchronized with the orbital period. The simultaneous modeling of V-, I-band, and radial velocity curves in the 2005 season suggests that the variability is dominated by one hot spot on the secondary component covering at least about 3.5% of the stellar surface and about 420K hotter than the unperturbed photosphere. Such a spot may originate from the material of the circum...

  20. Discovery of two magnetic massive stars in the Orion Nebula Cluster: a clue to the origin of neutron star magnetic fields?

    CERN Document Server

    Petit, V; Drissen, L; Montmerle, T; Alecian, E

    2008-01-01

    The origin of the magnetic fields in neutron stars, and the physical differences between magnetars and strongly magnetised radio pulsars are still under vigorous debate. It has been suggested that the properties of the progenitors of neutron stars (the massive OB stars), such as rotation, magnetic fields and mass, may play an important role in the outcome of core collapse leading to type II SNe. Therefore, knowing the magnetic properties of the progenitor OB stars would be an important asset for constraining models of stellar evolution leading to the birth of a neutron star. We present here the beginning of a broad study with the goal of characterising the magnetic properties of main sequence massive OB stars. We report the detection of two new massive magnetic stars in the Orion Nebula Cluster: Par 1772 (HD 36982) and NU Ori (HD 37061), for which the estimated dipole polar strengths, with 1 sigma error bars, are 1150 (+320,-200) G and 650 (+220,-170) G respectively.

  1. Astrometry with the Hubble Space Telescope: Trigonometric Parallaxes of Planetary Nebula Nuclei: NGC 6853, NGC 7293, Abell 31, and DeHt 5

    CERN Document Server

    Benedict, G Fritz; Napiwotzki, Ralf; Harrison, Thomas E; Harris, Hugh C; Nelan, Edmund; Bond, Howard E; Patterson, Richard J; Ciardullo, Robin

    2009-01-01

    We present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix), Abell 31, and DeHt 5. This paper details our reduction and analysis using DeHt 5 as an example. We obtain these planetary nebula nuclei (PNNi) parallaxes with astrometric data from Fine Guidance Sensors FGS 1R and FGS 3, white-light interferometers on the Hubble Space Telescope (HST). Proper motions, spectral classifications and VJHKT_2M and DDO51 photometry of the stars comprising the astrometric reference frames provide spectrophotometric estimates of reference star absolute parallaxes. Introducing these into our model as observations with error, we determine absolute parallaxes for each PNN. Weighted averaging with previous independent parallax measurements yields an average parallax precision, \\sigma_{\\pi}/\\pi = 5 %. Derived distances are: d_{NGC 6853}=405^{+28}_{-25}pc, d_{NGC 7293}=216^{+14}_{-12} pc, d_{Abell 31} = 621^{+91}_{-70} pc, and d_{DeHt 5} = ...

  2. Butterfly Nebula

    Science.gov (United States)

    1997-01-01

    The Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) is back at work, capturing this image of the 'butterfly wing'- shaped nebula, NGC 2346. The nebula is about 2,000 light-years away from Earth in the direction of the constellation Monoceros. It represents the spectacular 'last gasp' of a binary star system at the nebula's center. The image was taken on March 6, 1997 as part of the recommissioning of the Hubble Space Telescope's previously installed scientific instruments following the successful servicing of the HST by NASA shuttle astronauts in February. WFPC2 was installed in HST during the servicing mission in 1993. At the center of the nebula lies a pair of stars that are so close together that they orbit around each other every 16 days. This is so close that, even with Hubble, the pair of stars cannot be resolved into its two components. One component of this binary is the hot core of a star that has ejected most of its outer layers, producing the surrounding nebula. Astronomers believe that this star, when it evolved and expanded to become a red giant, actually swallowed its companion star in an act of stellar cannibalism. The resulting interaction led to a spiraling together of the two stars, culminating in ejection of the outer layers of the red giant. Most of the outer layers were ejected into a dense disk, which can still be seen in the Hubble image, surrounding the central star. Later the hot star developed a fast stellar wind. This wind, blowing out into the surrounding disk, has inflated the large, wispy hourglass-shaped wings perpendicular to the disk. These wings produce the butterfly appearance when seen in projection. The total diameter of the nebula is about one-third of a light-year, or 2 trillion miles.

  3. A Slice of Orion

    Science.gov (United States)

    2006-01-01

    [figure removed for brevity, see original site] Extended Orion Nebula Cloud This image composite shows a part of the Orion constellation surveyed by NASA's Spitzer Space Telescope. The shape of the main image was designed by astronomers to roughly follow the shape of Orion cloud A, an enormous star-making factory containing about 1,800 young stars. This giant cloud includes the famous Orion nebula (bright circular area in 'blade' part of hockey stick-shaped box at the bottom), which is visible to the naked eye on a clear, dark night as a fuzzy star in the hunter constellation's sword. The region that makes up the shaft part of the hockey stick box stretches 70 light-years beyond the Orion nebula. This particular area does not contain massive young stars like those of the Orion nebula, but is filled with 800 stars about the same mass as the sun. These sun-like stars don't live in big 'cities,' or clusters, of stars like the one in the Orion nebula; instead, they can be found in small clusters (right inset), or in relative isolation (middle insert). In the right inset, developing stars are illuminating the dusty cloud, creating small wisps that appear greenish. The stars also power speedy jets of gas (also green), which glow as the jets ram into the cloudy material. Since infrared light can penetrate through dust, we see not only stars within the cloud, but thousands of stars many light-years behind it, which just happen to be in the picture like unwanted bystanders. Astronomers carefully separate the young stars in the Orion cloud complex from the bystanders by looking for their telltale infrared glow. The infrared image shows light captured by Spitzer's infrared array camera. Light with wavelengths of 8 and 5.8 microns (red and orange) comes mainly from dust that has been heated by starlight. Light of 4.5 microns (green) shows hot gas and dust; and light of 3.6 microns (blue) is from starlight.

  4. The curious morphology and orientation of Orion proplyd HST-10

    CERN Document Server

    Shuping, Ralph Y; Bally, John; Morris, Mark R

    2013-01-01

    HST-10 is one of the largest proplyds in the Orion Nebula and is located approximately 1' SE of the Trapezium. Unlike other proplyds in Orion, however, the long-axis of HST-10 does not align with theta 1 C Ori, but is instead aligned with the rotational axis of the HST-10 disk. This cannot be easily explained using current photo-evaporation models. In this letter, we present high spatial resolution near-infrared images of the Orion proplyd HST-10 using Keck/NIRC2 with the Laser Guide Star Adaptive Optics system, along with multi-epoch analysis of HH objects near HST-10 using Hubble Space Telescope WFPC2 and ACS cameras. Our narrow-band near-IR images resolve the proplyd ionization front (IF) and circumstellar disk down to 23 AU at the distance to Orion in Br gamma, He I, H_2, and PAH emission. Br gamma and He I emission primarily trace the IF (with the disk showing prominently in silhouette), while the H_2 and PAH emission trace the surface of the disk itself. PAH emission also traces small dust grains within...

  5. Orion: The Final Epoch (OrionTFE)

    Science.gov (United States)

    Megeath, Tom; Allen, Tom; Arce, Hector; Booker, Joseph; Calvet, Nuria; Flaherty, Kevin; Furlan, Elise; Fischer, Will; Gonzales, Beatriz; Gutermuth, Rob; Hartman, Lee; Henning, Thomas; Hora, Joe; Karnath, Nicole; Kim, Kyoung Hee; Kounkel, Marina; Mazur, Brian; Offner, Stella; Osorio, Mayra; Pillitteri, Ignazio; Pipher, Judy; Prchlik, Jakub; Rebull, Luisa; Terebey, Susan; Tobin, John; Stanke, Thomas; Stutz, Amelia; Watson, Dan; Wolk, Scott

    2016-08-01

    The Orion molecular clouds are an essential laboratory for studying low mass star formation over the broad range of environments in which they form. Starting with the Spitzer survey of Orion in 2004, more than a decade of observations with Spitzer, WISE, HST and Herschel, have accumulated an unparalleled characterization of the young stellar object population in Orion. We propose a final epoch of observations divided into two separate, complementary observations: A repeat of the entire Orion molecular cloud survey to 1.) identify ejected stars from clusters, 2.) measure the bulk proper motions of groups and clusters of stars, 3.) constrain the rate of luminous, accretion driven outbursts from both protostars and pre-main sequence stars with disks and 4.) use proper motions of IR Herbig-Haro knots as a fossil record of previous accretion events. A high cadence variability survey of the L1641 cloud extending the YSOVAR variability survey of the Orion Nebula Cluster across the Orion A cloud with the goals of 1.) constraining the star formation history of Orion A, 2.) studying the evolution of mid-IR variability from the protostellar to pre-main sequence phase, 3.) searching for periodicities in (nearly) edge-on protostars and disks due to orbiting clumps and structures from orbiting planets, and 4.) assessing whether inner disk processes - as traced by variability - are affected by their birth environment. This program completes an unparalleled, > 12 year multi-epoch, mid-IR study of the nearest large molecular cloud complex with both a wide spatial coverage and a uniformity that will not be exceeded in the forseeable future. It will place unique constraints on the highly dynamic processes that control low mass star formation, serve as a pathfinder to molecular cloud surveys of WFIRST, and provide well characterized targets needed to study mass accretion and planet formation around young low mass stars with SOFIA and JWST.

  6. Astrometry with Hubble Space Telescope: A Parallax of the Central Star of the Planetary Nebula NGC 6853

    CERN Document Server

    Benedict, G F; Fredrick, L W; Harrison, T E; Skrutskie, M F; Slesnick, C L; Rhee, J; Patterson, R J; Nelan, E; Jefferys, W H; Van Altena, W; Montemayor, T; Shelus, P J; Franz, O G; Wasserman, L H; Hemenway, P D; Duncombe, R L; Story, D; Whipple, A L; Bradley, A J

    2003-01-01

    We present an absolute parallax and relative proper motion for the central star of the planetary nebula NGC 6853 (The Dumbell). We obtain these with astrometric data from FGS 3, a white-light interferometer on {\\it HST}. Spectral classifications and VRIJHKT$_2$M and DDO51 photometry of the stars comprising the astrometric reference frame provide spectrophotometric estimates of their absolute parallaxes. Introducing these into our model as observations with error, we find $\\pi_{abs} = 2.10 \\pm 0.48$ mas for the DAO central star of NGC 6853. A weighted average with a previous ground-based USNO determination yields $\\pi_{abs} = 2.40 \\pm 0.32$. We assume that the extinction suffered by the reference stars nearest (in angular separation and distance) to the central star is the same as for the central star. Correcting for color differences, we find $$ = 0.30 $ \\pm $ 0.06 for the central star, hence, an absolute magnitude M$_V = 5.48^{-0.16}_{+0.15}$. A recent determination of the central star effective temperature ...

  7. Astrometry With the Hubble Space Telescope: Trigonometric Parallaxes of Planetary Nebula Nuclei NGC 6853, NGC 7293, ABELL 31, and DeHt 5

    Science.gov (United States)

    Benedict, G. F.; McArthur, Barbara E.; Napiwotzki, Ralf; Harrison, Thomas E.; Harris, Hugh C.; Nelan, Edmund; Bond, Howard E; Patterson, Richard J.; Ciardullo, Robin

    2009-01-01

    We present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix), Abell 31, and DeHt 5. This paper details our reduction and analysis using DeHt 5 as an example. We obtain these planetary nebula nuclei (PNNi) parallaxes with astrometric data from Fine Guidance Sensors FGS 1r and FGS 3, white-light interferometers on the Hubble Space Telescope. Proper motions, spectral classifications and VJHKT2M and DDO51 photometry of the stars comprising the astrometric reference frames provide spectrophotometric estimates of reference star absolute parallaxes. Introducing these into our model as observations with error, we determine absolute parallaxes for each PNN. Weighted averaging with previous independent parallax measurements yields an average parallax precision, sigma (sub pi)/ pi = 5%. Derived distances are: d(sub NGC6853) = 405(exp +28 sub -25) pc, d(sub NGC7293) = 216(exp +14 sub -12) pc, d(sub Abell31) = 621(exp +91 sub -70) pc, and d(sub DeHt5) = 345(exp +19 sub -17) pc. These PNNi distances are all smaller than previously derived from spectroscopic analyses of the central stars. To obtain absolute magnitudes from these distances requires estimates of interstellar extinction. We average extinction measurements culled from the literature, from reddening based on PNNi intrinsic colors derived from model SEDs, and an assumption that each PNN experiences the same rate of extinction as a function of distance as do the reference stars nearest (in angular separation) to each central star. We also apply Lutz-Kelker bias corrections. The absolute magnitudes and effective temperatures permit estimates of PNNi radii through both the Stefan-Boltzmann relation and Eddington fluxes. Comparing absolute magnitudes with post-AGB models provides mass estimates. Masses cluster around 0.57 solar Mass, close to the peak of the white dwarf mass distribution. Adding a few more PNNi with well

  8. Hubble Space Telescope Detection of the Millisecond Pulsar J2124-3358 and its Far-ultraviolet Bow Shock Nebula

    Science.gov (United States)

    Rangelov, B.; Pavlov, G. G.; Kargaltsev, O.; Reisenegger, A.; Guillot, S.; van Kerkwijk, M. H.; Reyes, C.

    2017-02-01

    We observed the nearby millisecond pulsar J2124–3358 with the Hubble Space Telescope in broad far-UV (FUV) and optical filters. The pulsar is detected in both bands with fluxes F(1250–2000 Å) = (2.5 ± 0.3) × 10‑16 erg s‑1 cm‑2 and F(3800–6000 Å) = (6.4 ± 0.4) × 10‑17 erg s‑1 cm‑2, which corresponds to luminosities of ≈5.8 × 1027 and 1.4 × 1027 erg s‑1, for d = 410 pc and E(B ‑ V) = 0.03. The optical-FUV spectrum can be described by a power-law model, {f}ν \\propto {ν }α , with slope α = 0.18–0.48 for a conservative range of color excess, E(B ‑ V) = 0.01–0.08. Since a spectral flux rising with frequency is unusual for pulsar magnetospheric emission in this frequency range, it is possible that the spectrum is predominantly magnetospheric (power law with α neutron star surface in the FUV. For a neutron star radius of 12 km, the surface temperature would be between 0.5 × 105 and 2.1 × 105 K for α ranging from ‑1 to 0, E(B ‑ V) = 0.01–0.08, and d = 340–500 pc. In addition to the pulsar, the FUV images reveal extended emission that is spatially coincident with the known Hα bow shock, making PSR J2124–3358 the second pulsar (after PSR J0437‑4715) with a bow shock detected in the FUV.

  9. Orion revisited. III. The Orion Belt population

    Science.gov (United States)

    Kubiak, K.; Alves, J.; Bouy, H.; Sarro, L. M.; Ascenso, J.; Burkert, A.; Forbrich, J.; Großschedl, J.; Hacar, A.; Hasenberger, B.; Lombardi, M.; Meingast, S.; Köhler, R.; Teixeira, P. S.

    2017-02-01

    Aims: This paper continues our study of the foreground population to the Orion molecular clouds. The goal is to characterize the foreground population north of NGC 1981 and to investigate the star formation history in the large Orion star-forming region. We focus on a region covering about 25 square degrees, centered on the ɛ Orionis supergiant (HD 37128, B0 Ia) and covering the Orion Belt asterism. Methods: We used a combination of optical (SDSS) and near-infrared (2MASS) data, informed by X-ray (XMM-Newton) and mid-infrared (WISE) data, to construct a suite of color-color and color-magnitude diagrams for all available sources. We then applied a new statistical multiband technique to isolate a previously unknown stellar population in this region. Results: We identify a rich and well-defined stellar population in the surveyed region that has about 2000 objects that are mostly M stars. We infer the age for this new population to be at least 5 Myr and likely 10 Myr and estimate a total of about 2500 members, assuming a normal IMF. This new population, which we call the Orion Belt population, is essentially extinction-free, disk-free, and its spatial distribution is roughly centered near ɛ Ori, although substructure is clearly present. Conclusions: The Orion Belt population is likely the low-mass counterpart to the Ori OB Ib subgroup. Although our results do not rule out Blaauw's sequential star formation scenario for Orion, we argue that the recently proposed blue streams scenario provides a better framework on which one can explain the Orion star formation region as a whole. We speculate that the Orion Belt population could represent the evolved counterpart of an Orion nebula-like cluster. The catalog (Full Table A.1) is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A124

  10. Dismantling Hubble's Legacy?

    Science.gov (United States)

    Way, Michael J.

    2014-01-01

    Edwin Hubble is famous for a number of discoveries that are well known to amateur and professional astronomers, students and even the general public. The origins of three of the most well-known discoveries are examined: The distances to nearby spiral nebulae, the classification of extragalactic-nebulae and the Hubble constant. In the case of the first two a great deal of supporting evidence was already in place, but little credit was given. The Hubble Constant had already been estimated in 1927 by Georges Lemaitre with roughly the same value that Hubble obtained in 1929 using redshifts provided mostly by Vesto M. Slipher. These earlier estimates were not adopted or were forgotten by the astronomical community for complex scientific, sociological and psychological reasons.

  11. The ALMA View of the OMC1 Explosion in Orion

    Science.gov (United States)

    Bally, John; Ginsburg, Adam; Arce, Hector; Eisner, Josh; Youngblood, Allison; Zapata, Luis; Zinnecker, Hans

    2017-03-01

    Most massive stars form in dense clusters where gravitational interactions with other stars may be common. The two nearest forming massive stars, the BN object and Source I, located behind the Orion Nebula, were ejected with velocities of ∼29 and ∼13 km s‑1 about 500 years ago by such interactions. This event generated an explosion in the gas. New ALMA observations show in unprecedented detail, a roughly spherically symmetric distribution of over a hundred 12CO J = 2‑1 streamers with velocities extending from V LSR = ‑150 to +145 km s‑1. The streamer radial velocities increase (or decrease) linearly with projected distance from the explosion center, forming a “Hubble Flow” confined to within 50″ of the explosion center. They point toward the high proper-motion, shock-excited H2 and [Fe ii] “fingertips” and lower-velocity CO in the H2 wakes comprising Orion's “fingers.” In some directions, the H2 “fingers” extend more than a factor of two farther from the ejection center than the CO streamers. Such deviations from spherical symmetry may be caused by ejecta running into dense gas or the dynamics of the N-body interaction that ejected the stars and produced the explosion. This ∼1048 erg event may have been powered by the release of gravitational potential energy associated with the formation of a compact binary or a protostellar merger. Orion may be the prototype for a new class of stellar explosiozn responsible for luminous infrared transients in nearby galaxies.

  12. X-ray deficiency on strong accreting T Tauri stars - Comparing Orion with Taurus

    CERN Document Server

    Bustamante, Ignacio; Bouy, Hervé; Manara, Carlo; Ribas, Álvaro; Riviere-Marichalar, Pablo

    2015-01-01

    Depending on whether a T Tauri star accretes material from its circumstellar disk or not, different X-ray emission properties can be found. The accretion shocks produce cool heating of the plasma, contributing to the soft X-ray emission from the star. Using X-ray data from the Chandra Orion Ultra-deep Project and accretion rates that were obtained with the Hubble Space Telescope/WFPC2 photometric measurements in the Orion Nebula Cluster, we studied the relation between the accretion processes and the X-ray emissions of a coherent sample of T Tauri sources in the region. We performed regression and correlation analyses of our sample of T Tauri stars between the X-ray parameters, stellar properties, and the accretion measurements. We find that a clear anti-correlation is present between the residual X-ray luminosity and the accretion rates in our samples in Orion that is consistent with that found on the XMM-Newton Extended Survey of the Taurus molecular cloud (XEST) study. We provide a catalog with X-ray lumin...

  13. Resolving the Shocks in Radio Galaxy Nebulae: Hubble Space Telescope and Radio Imaging of 3C 171, 3C 277.3, and PKS 2250-41

    Science.gov (United States)

    Tilak, Avanti; O'Dea, Christopher P.; Tadhunter, Clive; Wills, Karen; Morganti, Raffaella; Baum, Stefi A.; Koekemoer, Anton M.; Dallacasa, Daniele

    2005-12-01

    We present the results of Hubble Space Telescope (HST) WFPC2 medium-band and narrowband imaging and Very Large Array and MERLIN2 radio imaging of three powerful radio galaxies: 3C 171, 3C 277.3, and PKS 2250-41. We obtained images of the rest frame [O III] λ5007 and [O II] λ3727 line emission using the linear ramp filters on WFPC2. The correlations of the emission-line morphology and the [O III]/[O II] line ratios with the radio emission seen in ground-based observations are clarified by the HST imaging. We confirm that the radio lobes and hot spots are preferentially associated with lower ionization gas. The galaxy 3C 171 exhibits high surface brightness emission-line gas mainly along the radio source axis. The lowest ionization gas is seen at the eastern hot spot. In 3C 277.3 there is bright high-ionization gas (and continuum) offset just to the east of the radio knot K1. Our observations are consistent with previous work suggesting that this emission is produced by precursor gas ionized by the shock being driven into the cloud by the deflected radio jet. In PKS 2250-41 we resolve the emission-line arc that wraps around the outer rim of the western lobe. The lower ionization [O II] emission is nested just interior to the higher ionization [O III] emission, suggesting that we have resolved the cooling region behind the bow shock. We also detect possible continuum emission from the secondary hot spot. Thus, our observations support the hypothesis that in these sources the interaction between the expanding radio source and the ambient gas strongly influences the morphology, kinematics, and ionization of the gas. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. These observations are associated with program 6657 (principal investigator C. Tadhunter).

  14. Edwin Hubble

    Institute of Scientific and Technical Information of China (English)

    泓傑

    2006-01-01

    Edwin Powell Hubble(1889—1953)was an American astronomer, renowned for his discovery of galaxies beyond the Milky Way and the cosmological Redshift. Hubble was a tall,elegant,athletic man who at age 30 had an

  15. Most Detailed Image of the Crab Nebula

    Science.gov (United States)

    2005-01-01

    This new Hubble image -- one among the largest ever produced with the Earth-orbiting observatory -- shows the most detailed view so far of the entire Crab Nebula ever made. The Crab is arguably the single most interesting object, as well as one of the most studied, in all of astronomy. The image is the largest image ever taken with Hubble's WFPC2 workhorse camera. The Crab Nebula is one of the most intricately structured and highly dynamical objects ever observed. The new Hubble image of the Crab was assembled from 24 individual exposures taken with the NASA/ESA Hubble Space Telescope and is the highest resolution image of the entire Crab Nebula ever made.

  16. Dust in and near the orion nebula

    Directory of Open Access Journals (Sweden)

    C. R. O`Dell

    2002-01-01

    Full Text Available El modelo m as aceptado de la Nebulosa de Ori on es el de una ampolla, pero el modelo alternativo donde la apariencia de la nebulosa est a determinado por autoextinci on jam as ha sido realmente desechado. Hago un resumen de ambos modelos y muestro que las evidencias est an fuertemente en contra del modelo de autoextinci on y favorecen al de ampolla.

  17. A 3D view of the outflow in the Orion Molecular Cloud 1 (OMC-1)

    DEFF Research Database (Denmark)

    Nissen, H.D.; Cunningham, N.J.; Sherson, Maiken Gustafsson;

    2012-01-01

    The fast outflow emerging from a region associated with massive star formation in the Orion Molecular Cloud 1 (OMC-1), located behind the Orion Nebula, appears to have been set in motion by an explosive event. Here we study the structure and dynamics of outflows in OMC-1. We combine radial velocity...

  18. Orion revisited. II. The foreground population to Orion A

    CERN Document Server

    Bouy, H; Bertin, E; Sarro, L M; Barrado, D

    2014-01-01

    Following the recent discovery of a large population of young stars in front of the Orion Nebula, we carried out an observational campaign with the DECam wide-field camera covering ~10~deg^2 centered on NGC 1980 to confirm, probe the extent of, and characterize this foreground population of pre-main-sequence stars. We confirm the presence of a large foreground population towards the Orion A cloud. This population contains several distinct subgroups, including NGC1980 and NGC1981, and stretches across several degrees in front of the Orion A cloud. By comparing the location of their sequence in various color-magnitude diagrams with other clusters, we found a distance and an age of 380pc and 5~10Myr, in good agreement with previous estimates. Our final sample includes 2123 candidate members and is complete from below the hydrogen-burning limit to about 0.3Msun, where the data start to be limited by saturation. Extrapolating the mass function to the high masses, we estimate a total number of ~2600 members in the ...

  19. Chemical abundances in the protoplanetary disc LV 2 (Orion): clues to the causes of the abundance anomaly in H II regions

    Science.gov (United States)

    Tsamis, Y. G.; Walsh, J. R.; Vílchez, J. M.; Péquignot, D.

    2011-04-01

    Optical integral field spectroscopy of the archetype protoplanetary disc LV 2 in the Orion nebula is presented, taken with the Very Large Telescope (VLT) FLAMES/Argus fibre array. The detection of recombination lines (RLs) of C II and O II from this class of objects is reported, and the lines are utilized as abundance diagnostics. The study is complemented with the analysis of Hubble Space Telescope (HST) Faint Object Spectrograph ultraviolet and optical spectra of the target contained within the Argus field of view. By subtracting the local nebula background the intrinsic spectrum of the proplyd is obtained and its elemental composition is derived for the first time. The proplyd is found to be overabundant in carbon, oxygen and neon compared to the Orion nebula and the Sun. The simultaneous coverage over LV 2 of the C III]λ1908 and [O III]λ5007 collisionally excited lines (CELs) and C II and O II RLs has enabled us to measure the abundances of C2 + and O2 + for LV 2 with both sets of lines. The two methods yield consistent results for the intrinsic proplyd spectrum, but not for the proplyd spectrum contaminated by the generic nebula spectrum, thus providing one example where the long-standing abundance anomaly plaguing metallicity studies of H II regions has been resolved. These results would indicate that the standard forbidden-line methods used in the derivation of light metal abundances in H II regions in our own and other galaxies underestimate the true gas metallicity.

  20. The Hubble Tarantula Treasury Project

    Science.gov (United States)

    Sabbi, Elena; Lennon, D. J.; Anderson, J.; Van Der Marel, R. P.; Aloisi, A.; Boyer, M. L.; Cignoni, M.; De Marchi, G.; de Mink, S. E.; Evans, C. J.; Gallagher, J. S.; Gordon, K. D.; Gouliermis, D.; Grebel, E.; Koekemoer, A. M.; Larsen, S. S.; Panagia, N.; Ryon, J. E.; Smith, L. J.; Tosi, M.; Zaritsky, D. F.

    2014-01-01

    The Tarantula Nebula (a.k.a. 30 Doradus) in the Large Magellanic Cloud is one of the most famous objects in astronomy, with first astronomical references being more than 150 years old. Today the Tarantula Nebula and its ionizing cluster R136 are considered one of the few known starburst regions in the Local Group and an ideal test bed to investigate the temporal and spatial evolution of a prototypical starburst on a sub-cluster scale. The Hubble Tarantula Treasury Project (HTTP) is a panchromatic imaging survey of the stellar populations and ionized gas in the Tarantula Nebula that reaches into the sub-solar mass regime (eBook that explains how stars form and evolve using images from HTTP. The eBook utilizes emerging technology that works in conjunction with the built-in accessibility features in the Apple iPad to allow totally blind users to interactively explore complex astronomical images.

  1. Rotten Egg Nebula

    Science.gov (United States)

    1999-01-01

    Violent gas collisions that produced supersonic shock fronts in a dying star are seen in a new, detailed image from NASA's Hubble Space Telescope. The picture, taken by Hubble's Wide Field and Planetary Camera 2, is online at http://www.jpl.nasa.gov/images/wfpc . The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Stars like our Sun will eventually die and expel most of their material outward into shells of gas and dust. These shells eventually form some of the most beautiful objects in the universe, called planetary nebulae. 'This new image gives us a rare view of the early death throes of stars like our Sun. For the first time, we can see phenomena leading to the formation of planetary nebulae. Until now, this had only been predicted by theory, but had never been seen directly,' said Dr. Raghvendra Sahai, research scientist and member of the science team at JPL for the Wide Field and Planetary Camera 2. The object is sometimes called the Rotten Egg Nebula, because it contains a lot of sulphur, which would produce an awful odor if one could smell in space. The object is also known as the Calabash Nebula or by the technical name OH231.8+4.2. The densest parts of the nebula are composed of material ejected recently by the central star and accelerated in opposite directions. This material, shown as yellow in the image, is zooming away at speeds up to one and a half million kilometers per hour (one million miles per hour). Most of the star's original mass is now contained in these bipolar gas structures. A team of Spanish and American astronomers used NASA's Hubble Space Telescope to study how the gas stream rams into the surrounding material, shown in blue. They believe that such interactions dominate the formation process in planetary nebulae. Due to the high speed of the gas, shock-fronts are formed on impact and heat the surrounding gas. Although computer calculations have predicted the existence and structure of such shocks for

  2. Rotten Egg Nebula

    Science.gov (United States)

    1999-01-01

    Violent gas collisions that produced supersonic shock fronts in a dying star are seen in a new, detailed image from NASA's Hubble Space Telescope. The picture, taken by Hubble's Wide Field and Planetary Camera 2, is online at http://www.jpl.nasa.gov/images/wfpc . The camera was designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Stars like our Sun will eventually die and expel most of their material outward into shells of gas and dust. These shells eventually form some of the most beautiful objects in the universe, called planetary nebulae. 'This new image gives us a rare view of the early death throes of stars like our Sun. For the first time, we can see phenomena leading to the formation of planetary nebulae. Until now, this had only been predicted by theory, but had never been seen directly,' said Dr. Raghvendra Sahai, research scientist and member of the science team at JPL for the Wide Field and Planetary Camera 2. The object is sometimes called the Rotten Egg Nebula, because it contains a lot of sulphur, which would produce an awful odor if one could smell in space. The object is also known as the Calabash Nebula or by the technical name OH231.8+4.2. The densest parts of the nebula are composed of material ejected recently by the central star and accelerated in opposite directions. This material, shown as yellow in the image, is zooming away at speeds up to one and a half million kilometers per hour (one million miles per hour). Most of the star's original mass is now contained in these bipolar gas structures. A team of Spanish and American astronomers used NASA's Hubble Space Telescope to study how the gas stream rams into the surrounding material, shown in blue. They believe that such interactions dominate the formation process in planetary nebulae. Due to the high speed of the gas, shock-fronts are formed on impact and heat the surrounding gas. Although computer calculations have predicted the existence and structure of such shocks for

  3. Ghost Head Nebula

    Science.gov (United States)

    1999-01-01

    Looking like a colorful holiday card, a new image from NASA's Hubble Space Telescope reveals a vibrant green and red nebula far from Earth. The image of NGC 2080, taken by Hubble's Wide Field and Planetary Camera 2, designed and built by NASA's Jet Propulsion Laboratory, Pasadena, Calif., is available online at http://www.jpl.nasa.gov/images/wfpc . Images like this help astronomers investigate star formation in nebulas. NGC 2080, nicknamed 'The Ghost Head Nebula,' is one of a chain of star-forming regions lying south of the 30 Doradus nebula in the Large Magellanic Cloud. 30 Doradus is the largest star-forming complex in the local group of galaxies. This 'enhanced color' picture is composed of three narrow-band-filter images obtained by Hubble on March 28, 2000. The red and blue light come from regions of hydrogen gas heated by nearby stars. The green light on the left comes from glowing oxygen. The energy to illuminate the green light is supplied by a powerful stellar wind, a stream of high-speed particles coming from a massive star just outside the image. The central white region is a combination of all three emissions and indicates a core of hot, massive stars in this star-formation region. Intense emission from these stars has carved a bowl-shaped cavity in surrounding gas. In the white region, the two bright areas (the 'eyes of the ghost') - named A1 (left) and A2 (right) -- are very hot, glowing 'blobs' of hydrogen and oxygen. The bubble in A1 is produced by the hot, intense radiation and powerful stellar wind from one massive star. A2 contains more dust and several hidden, massive stars. The massive stars in A1 and A2 must have formed within the last 10,000 years, since their natal gas shrouds are not yet disrupted by the powerful radiation of the newborn stars. The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The

  4. An infrared study of Orion Molecular Cloud-2 (OMC-2)

    Science.gov (United States)

    Johnson, J. J.; Gehrz, R. D.; Jones, T. J.; Hackwell, J. A.; Grasdalen, G. L.

    1990-01-01

    This paper reports 1.2-23 micron photometry for 11 discrete sources in Orion Molecular Cloud-2 (OMC-2). These data, combined with H and K photometric and K polarimetric images, are used to model the cluster sources. Most appear to be young stars of roughly solar mass. Some have circumstellar dust reradiation or reflection nebulosity. A model based on single scattering of light from an exciting star explains some features of the IRS 1 nebula, the largest reflection nebula in OMC-2. However, the red colors and high surface brightness of the IRS 1 nebula require a cool excitation source that is more luminous than far-infrared observations would indicate.

  5. An infrared study of Orion Molecular Cloud-2 (OMC-2)

    Science.gov (United States)

    Johnson, J. J.; Gehrz, R. D.; Jones, T. J.; Hackwell, J. A.; Grasdalen, G. L.

    1990-01-01

    This paper reports 1.2-23 micron photometry for 11 discrete sources in Orion Molecular Cloud-2 (OMC-2). These data, combined with H and K photometric and K polarimetric images, are used to model the cluster sources. Most appear to be young stars of roughly solar mass. Some have circumstellar dust reradiation or reflection nebulosity. A model based on single scattering of light from an exciting star explains some features of the IRS 1 nebula, the largest reflection nebula in OMC-2. However, the red colors and high surface brightness of the IRS 1 nebula require a cool excitation source that is more luminous than far-infrared observations would indicate.

  6. Orion Scripted Interface Generator (OrionSIG)

    Science.gov (United States)

    Dooling, Robert J.

    2013-01-01

    The Orion spacecraft undergoing development at NASA and Lockheed Martin aims to launch the first humans to set foot on asteroids and Mars.' Sensors onboard Orion must transmit back to Earth astronomical amounts of data recording almost everything in 50,231 lb. (22,784 kg)2 of spacecraft, down to the temperatures, voltages, or torsions of even the most minor components. This report introduces the new Orion Scripted Interface Generator (OrionSIG) software created by summer 2013 NASA interns Robert Dooling and Samuel Harris. OrionSIG receives a list of Orion variables and produces a script to graph these measurements regardless of their size or type. The program also accepts many other input options to manipulate displays, such as limits on the graph's range or commands to graph different values in a reverse sawtooth wave. OrionSIG paves the way for monitoring stations on Earth to process, display, and test Orion data much more efficiently, a helpful asset in preparation for Orion's first test mission in 2014. Figure I.

  7. Hubble Diagram

    Science.gov (United States)

    Djorgovski, S.; Murdin, P.

    2000-11-01

    Initially introduced as a way to demonstrate the expansion of the universe, and subsequently to determine the expansion rate (the HUBBLE CONSTANT H0), the Hubble diagram is one of the classical cosmological tests. It is a plot of apparent fluxes (usually expressed as magnitudes) of some types of objects at cosmological distances, against their REDSHIFTS. It is used as a tool to measure the glob...

  8. Observing nebulae

    CERN Document Server

    Griffiths, Martin

    2016-01-01

    This book enables anyone with suitable instruments to undertake an examination of nebulae and see or photograph them in detail. Nebulae, ethereal clouds of gas and dust, are among the most beautiful objects to view in the night sky. These star-forming regions are a common target for observers and photographers. Griffiths describes many of the brightest and best nebulae and includes some challenges for the more experienced observer. Readers learn the many interesting astrophysical properties of these clouds, which are an important subject of study in astronomy and astrobiology. Non-mathematical in approach, the text is easily accessible to anyone with an interest in the subject. A special feature is the inclusion of an observational guide to 70 objects personally observed or imaged by the author. The guide also includes photographs of each object for ease of identification along with their celestial coordinates, magnitudes and other pertinent information. Observing Nebulae provides a ready resource to allow an...

  9. A Spitzer/IRAC Survey of the Orion Molecular Clouds

    OpenAIRE

    Megeath, S. T.; Flaherty, K M; Hora, J.; Allen, L E; Fazio, G. G.; Hartmann, L.; Myers, P. C.; J. Muzerolle; Pipher, J. L.; Siegler, N.; J. R. Stauffer; Young, E.

    2005-01-01

    We present initial results from a survey of the Orion A and B molecular clouds made with the InfraRed Array Camera (IRAC) onboard the Spitzer Space Telescope. This survey encompasses a total of 5.6 square degrees with the sensitivity to detect objects below the hydrogen burning limit at an age of 1 Myr. These observations cover a number of known star forming regions, from the massive star forming clusters in the Orion Nebula and NGC 2024, to small groups of low mass stars in the L1641. We com...

  10. Herschel Observations of Extraordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey toward Orion KL. I. Methods

    NARCIS (Netherlands)

    Crockett, Nathan R.; Bergin, Edwin A.; Neill, Justin L.; Favre, Cécile; Schilke, Peter; Lis, Dariusz C.; Bell, Tom A.; Blake, Geoffrey; Cernicharo, José; Emprechtinger, Martin; Esplugues, Gisela B.; Gupta, Harshal; Kleshcheva, Maria; Lord, Steven; Marcelino, Nuria; McGuire, Brett A.; Pearson, John; Phillips, Thomas G.; Plume, Rene; van der Tak, Floris; Tercero, Belén; Yu, Shanshan

    2014-01-01

    We present a comprehensive analysis of a broadband spectral line survey of the Orion Kleinmann-Low nebula (Orion KL), one of the most chemically rich regions in the Galaxy, using the HIFI instrument on board the Herschel Space Observatory. This survey spans a frequency range from 480 to 1907 GHz at

  11. Herschel Observations of Extra-Ordinary Sources (hexos) : Analysis of the Hifi 1.2 Thz Wide Spectral Survey Toward Orion KL

    NARCIS (Netherlands)

    Crockett, N. R.; Bergin, E. A.; Wang, S.; Blake, G.; Emprechtinger, M.; Lis, D.; Gupta, H.; Pearson, J.; Yu, S.; Bell, T.; Cernicharo, J.; Lord, S.; Plume, R.; Schilke, P.; van der Tak, F.

    2011-01-01

    We present a full spectral survey of the Kleiman-Low nebula within the Orion Molecular Cloud (Orion KL), one of the most chemically rich regions in the galaxy, using the HIFI instrument on board the Herschel Space Observatory. These observations span a frequency range of 490 -- 1240 GHz and 1430 --

  12. Herschel Observations of EXtra-Ordinary Sources (HEXOS): Analysis of the HIFI 1.2 THz Wide Spectral Survey Toward Orion KL

    NARCIS (Netherlands)

    Crockett, N. R.; Bergin, E. A.; Bell, T. A.; Blake, G.; Cernicharo, J.; Emprechtinger, M.; Gupta, H.; Lord, S.; Pearson, J.; Plume, R.; Schilke, P.; van der Tak, F.; Wang, S.; Yu, S.

    2011-01-01

    We present a full spectral survey of the Kleiman-Low nebula within the Orion Molecular Cloud (Orion KL), one of the most chemically rich regions in the galaxy, using the HIFI instrument on board the Herschel Space Observatory. These observations, shown in the figure below, span a frequency range of

  13. Herschel Observations of Extra-Ordinary Sources (hexos): Analysis of the Hifi 1.2 Thz Wide Spectral Survey Toward Orion KL

    NARCIS (Netherlands)

    Crockett, N. R.; Bergin, E. A.; Wang, S.; Blake, G.; Emprechtinger, M.; Lis, D.; Gupta, H.; Pearson, J.; Yu, S.; Bell, T.; Cernicharo, J.; Lord, S.; Plume, R.; Schilke, P.; van der Tak, F.

    2011-01-01

    We present a full spectral survey of the Kleiman-Low nebula within the Orion Molecular Cloud (Orion KL), one of the most chemically rich regions in the galaxy, using the HIFI instrument on board the Herschel Space Observatory. These observations span a frequency range of 490 -- 1240 GHz and 1430 --

  14. New infrared observations of IRS1, IRS3 and the adjacent nebula in the OMC-2 cluster

    Science.gov (United States)

    Pendleton, Y.; Werner, M.; Capps, R.; Dinerstein, H. L.

    1984-01-01

    Near infrared reflection nebulae are often observed around embedded protostellar objects. New observations of the infrared cluster of low luminosity protostars in Orion Molecular Cloud 2 (OMC2) are reported. The asymmetric distribution of the extended emission seen about IRS1 is in fact another infrared reflection nebulae. Observations of near infrared polarimetry, photometry, and spectrophotometry were carried out.

  15. A Spitzer/IRAC Survey of the Orion Molecular Clouds

    CERN Document Server

    Megeath, S T; Hora, J; Allen, L E; Fazio, G G; Hartmann, L; Myers, P C; Muzerolle, J; Pipher, J L; Siegler, N; Stauffer, J R; Young, E

    2005-01-01

    We present initial results from a survey of the Orion A and B molecular clouds made with the InfraRed Array Camera (IRAC) onboard the Spitzer Space Telescope. This survey encompasses a total of 5.6 square degrees with the sensitivity to detect objects below the hydrogen burning limit at an age of 1 Myr. These observations cover a number of known star forming regions, from the massive star forming clusters in the Orion Nebula and NGC 2024, to small groups of low mass stars in the L1641. We combine the IRAC photometry with photometry from the 2MASS point source catalog and use the resulting seven band data to identify stars with infrared excesses due to dusty disks and envelopes. Using the presence of an infrared excess as an indicator of youth, we show the distribution of young stars and protostars in the two molecular clouds. We find that roughly half of the stars are found in dense clusters surrounding the two regions of recent massive star formation in the Orion clouds, NGC 2024 and the Orion Nebula.

  16. The star fish twins: Two young planetary nebulae with extreme multipolar morphology

    Science.gov (United States)

    Sahai, R.

    2000-01-01

    We present alpha images of two objects, He 2-47 and M1-37, obtained during a Hubble Space Telescope imaging survey of young planetary nebulae (PNs) selected on the basis of their low-excitation characteristics.

  17. Hubble, Hubble's law and the expanding universe

    OpenAIRE

    Bagla, J. S.

    2009-01-01

    Hubble's name is associated closely with the idea of an expanding universe as he discovered the relation between the recession velocity and distances of galaxies. Hubble also did a lot of pioneering work on the distribution of galaxies in the universe. In this article we take a look at Hubble's law and discuss how it relates with models of the universe. We also give a historical perspective of the discoveries that led to the Hubble's law.

  18. Hubble, Hubble's law and the expanding universe

    OpenAIRE

    Bagla, J. S.

    2009-01-01

    Hubble's name is associated closely with the idea of an expanding universe as he discovered the relation between the recession velocity and distances of galaxies. Hubble also did a lot of pioneering work on the distribution of galaxies in the universe. In this article we take a look at Hubble's law and discuss how it relates with models of the universe. We also give a historical perspective of the discoveries that led to the Hubble's law.

  19. Stingray Nebula

    Science.gov (United States)

    1996-01-01

    This Wide Field and Planetary Camera 2 image captures the infancy of the Stingray nebula (Hen-1357), the youngest known planetary nebula. In this image, the bright central star is in the middle of the green ring of gas. Its companion star is diagonally above it at 10 o'clock. A spur of gas (green) is forming a faint bridge to the companion star due to gravitational attraction. The image also shows a ring of gas (green) surrounding the central star, with bubbles of gas to the lower left and upper right of the ring. The wind of material propelled by radiation from the hot central star has created enough pressure to blow open holes in the ends of the bubbles, allowing gas to escape. The red curved lines represent bright gas that is heated by a 'shock' caused when the central star's wind hits the walls of the bubbles. The nebula is as large as 130 solar systems, but, at its distance of 18,000 light-years, it appears only as big as a dime viewed a mile away. The Stingray is located in the direction of the southern constellation Ara (the Altar). The colors shown are actual colors emitted by nitrogen (red), oxygen (green), and hydrogen (blue).

  20. ORION laser target diagnostics.

    Science.gov (United States)

    Bentley, C D; Edwards, R D; Andrew, J E; James, S F; Gardner, M D; Comley, A J; Vaughan, K; Horsfield, C J; Rubery, M S; Rothman, S D; Daykin, S; Masoero, S J; Palmer, J B; Meadowcroft, A L; Williams, B M; Gumbrell, E T; Fyrth, J D; Brown, C R D; Hill, M P; Oades, K; Wright, M J; Hood, B A; Kemshall, P

    2012-10-01

    The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

  1. ORION laser target diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bentley, C. D.; Edwards, R. D.; Andrew, J. E.; James, S. F.; Gardner, M. D.; Comley, A. J.; Vaughan, K.; Horsfield, C. J.; Rubery, M. S.; Rothman, S. D.; Daykin, S.; Masoero, S. J.; Palmer, J. B.; Meadowcroft, A. L.; Williams, B. M.; Gumbrell, E. T.; Fyrth, J. D.; Brown, C. R. D.; Hill, M. P.; Oades, K. [Plasma Physics Department, Atomic Weapons Establishment, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); and others

    2012-10-15

    The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

  2. Hubble Space Telescope NICMOS Polarization Measurements of OMC-1

    Science.gov (United States)

    Simpson, Janet P.; Colgan, Sean W. J.; Erickson, Edwin F.; Burton, Michael G.; Schultz, A. S. B.

    2006-01-01

    We present 2 micrometer polarization measurements of positions in the BN region of the Orion Molecular Cloud (OMC-1) made with NICMOS Camera 2 (0.2" resolution) on Hubble Space Telescope. Our goals are to seek the sources of heating for IRc2, 3, 4, and 7, identify possible young stellar objects (YSOs), and characterize the grain alignment in the dust clouds along the lines-of-sight to the stars. Our results are as follows: BN is approximately 29% polarized by dichroic absorption and appears to be the illuminating source for most of the nebulosity to its north and up to approximately 5" to its south. Although the stars are probably all polarized by dichroic absorption, there are a number of compact, but non-point-source, objects that could be polarized by a combination of both dichroic absorption and local scattering of star light. We identify several candidate YSOs, including an approximately edge-on bipolar YSO 8.7" east of BN, and a deeply-embedded IRc7, all of which are obviously self-luminous at mid-infrared wavelengths and may be YSOs. None of these is a reflection nebula illuminated by a star located near radio source I, as was previously suggested. Other IRc sources are clearly reflection nebulae: IRc3 appears to be illuminated by IRc2-B or a combination of the IRc2 sources, and IRc4 and IRc5 appear to be illuminated by an unseen star in the vicinity of radio source I, or by Star n or IRc2-A. Trends in the magnetic field direction are inferred from the polarization of the 26 stars that are bright enough to be seen as NICMOS point sources. Their polarization ranges from N less than or equal to 1% (all stars with this low polarization are optically visible) to greater than 40%. The most polarized star has a polarization position angle different from its neighbors by approximately 40 degrees, but in agreement with the grain alignment inferred from millimeter polarization measurements of the cold dust cloud in the southern part of OMC-1. The polarization

  3. Featured Image: A Detailed Look at the Crab Nebula

    Science.gov (United States)

    Kohler, Susanna

    2017-07-01

    Planning on watching fireworks tomorrow? Heres an astronomical firework to help you start the celebrations! A new study has stunningly detailed the Crab Nebula (click for a closer look), a nebula 6,500 light-years away thought to have been formedby a supernova explosion and the subsequent ultrarelativistic wind emitted by the pulsar at its heart. Led by Gloria Dubner (University of Buenos Aires), the authors of this study obtained new observations of the Crab Nebula from five different telescopes. They compiled these observations to compare the details of the nebulas structure across different wavelengths, which allowedthem to learnabout the sources of various features within the nebula. In the images above, thetop left shows the 3 GHz data from the Very Large Array (radio). Moving clockise, the radio data (shown in red) is composited with: infrared data from Spitzer Space Telescope, optical continuum from Hubble Space Telescope, 500-nm optical datafrom Hubble, and ultraviolet data from XMM-Newton. The final two images are of the nebula center, and they are composites of the radio imagewith X-ray data from Chandra and near-infrared data from Hubble. To read more about what Dubner and collaborators learned (and to see more spectacular images!), check out the paper below.CitationG. Dubner et al 2017 ApJ 840 82. doi:10.3847/1538-4357/aa6983

  4. Orion revisited III. The Orion Belt population

    CERN Document Server

    Kubiak, K; Bouy, H; Sarro, L M; Ascenso, J; Burkert, A; Forbrich, J; Großschedl, J; Hacar, A; Hasenberger, B; Lombardi, M; Meingast, S; Köhler, R; Teixeira, P S

    2016-01-01

    This paper continues our study of the foreground population to the Orion molecular clouds. The goal is to characterize the foreground population north of NGC 1981 and to investigate the star formation history in the large Orion star-forming region. We focus on a region covering about 25 square degrees, centered on the $\\epsilon$ Orionis supergiant (HD 37128, B0\\,Ia) and covering the Orion Belt asterism. We used a combination of optical (SDSS) and near-infrared (2MASS) data, informed by X-ray (\\textit{XMM-Newton}) and mid-infrared (WISE) data, to construct a suite of color-color and color-magnitude diagrams for all available sources. We then applied a new statistical multiband technique to isolate a previously unknown stellar population in this region. We identify a rich and well-defined stellar population in the surveyed region that has about 2\\,000 objects that are mostly M stars. We infer the age for this new population to be at least 5\\, Myr and likely $\\sim10$\\,Myr and estimate a total of about 2\\,500 mem...

  5. The Stingray nebula: watching the rapid evolution of a newly born planetary nebula.

    Science.gov (United States)

    Bobrowsky, M.; Sahu, K. C.; Parthasarathy, M.; García-Lario, Pedro

    The formation and early evolution of planetary nebulae represent one of the most poorly understood phases of stellar evolution ( Kwok, 1987; Maddox, 1995). One of the youngest, the Stingray Nebula (He3-1357) ( Henize, 1967; Henize, 1976), shows all the tell-tale signs of a newly born planetary nebula: it has become ionized only within the past few decades ( Parthasarathy et al., 1993); the mass-loss from the central star has ceased within the past few years; and the central star is becoming hotter and fainter as expected from a star on its way to becoming a DA white dwarf ( Parthasarathy et al., 1995). The Stingray Nebula thus provides the ideal laboratory for examining the early structure and evolution of this class of objects. Images of the Stingray Nebula, obtained with the Hubble Space Telescope, show for the first time that its multiple expulsions of matter are focused by an equatorial ring and bubbles of gas located on opposite sides of the ring ( Bobrowsky et al., 1995). The position angle of the outflows has changed, possibly as a result of precessional motion induced by the presence of a companion star. This is consistent with the precessing jet model by Livio & Pringle (1996). Indeed, we have reported the discovery of a companion star in the Stingray Nebula ( Bobrowsky et al., 1998). Finally, we present evidence of the companion star dynamically distorting the gas in this newly-born planetary nebula.

  6. The Orion HII Region and the Orion Bar in the Mid-Infrared

    CERN Document Server

    Salgado, F; Adams, J D; Herter, T L; Tielens, A G G M

    2016-01-01

    We present mid-infrared photometry of the Orion Bar obtained with FORCAST aboard SOFIA at 6.4, 6.6, 7.7, 19.7, 31.5 and 37.1 \\um. By complementing this observations with archival FORCAST and \\emph{Herschel}/PACS images we are able to construct a complete infrared spectral energy distribution of the Huygens region in the Orion nebula By comparing the infrared images with gas tracers, we find that PACS maps trace the molecular cloud, while the FORCAST data trace the photodissociation region (PDR) and HII region. Analysis of the energetics of the region reveal that the PDR extends for 0.28~pc along the line-of-sight and that the Bar is inclined at an angle of $4\\degr$. The infrared and submillimeter images reveal that the Orion Bar represents a swept up shell with a thickness of 0.1~pc. The mass of the shell implies a shock velocity of $\\simeq 3$ km/s and an age of $\\simeq 10^5$ yr for the HII region. Our analysis shows that the UV and infrared dust opacities in the HII region and the PDR are a factor 5 to 10 lo...

  7. A Deep Newfirm Survey of the Orion B Cloud

    Science.gov (United States)

    Megeath, Tom; Allen, Lori; Allen, Tom; Gutermuth, Rob; Kryukova, Erin; Stutz, Amelia; Fischer, Will; Ali, Babar

    2012-08-01

    We propose deep NEWFIRM H and Ks observations of the Orion B Molecular Cloud. The Orion B cloud is the 2nd most active molecular cloud within 420 pc of the Sun, after the Orion A cloud. Spitzer identified 528 pre-main sequence stars with disks and 100 protostars in the Orion B cloud. The NEWFIRM survey will obtain deep H and Ks data with sensitivities 4-5 magnitudes deeper than the 2MASS survey. The goals are the following: Detect deeply embedded protostars: these data are a crucial input to a Herschel, Spitzer and Hubble survey of over 300 Spitzer selected protostars in the Orion A and B clouds and are needed to determine the inclination of the protostars and the geometry of their outflow cavities. Map the gas column density by extinction using the combined NEWFIRM and Spitzer 3.6 (micron) data. By correlating column density with the properties of protostars and the density of young stars, we can better understand how how the gas column density influences the rate of star formation and the properties of the nascent stars forming within the gas.

  8. The Orion HII Region and the Orion Bar in the Mid-infrared

    Science.gov (United States)

    Salgado, F.; Berné, O.; Adams, J. D.; Herter, T. L.; Keller, L. D.; Tielens, A. G. G. M.

    2016-10-01

    We present mid-infrared photometry of the Orion bar obtained with the Faint Object infraRed Camera for the SOFIA Telescope (FORCAST) on board SOFIA at 6.4, 6.6, 7.7, 19.7, 31.5, and 37.1 μm. By complementing this observation with archival FORCAST and Herschel/PACS images, we are able to construct a complete infrared spectral energy distribution of the Huygens region in the Orion nebula. Comparing the infrared images with gas tracers, we find that PACS maps trace the molecular cloud, while the FORCAST data trace the photodissociation region (PDR) and the H ii region. Analysis of the energetics of the region reveal that the PDR extends for 0.28 pc along the line of sight and that the bar is inclined at an angle of 4°. The infrared and submillimeter images reveal that the Orion bar represents a swept-up shell with a thickness of 0.1 pc. The mass of the shell implies a shock velocity of ≃3 km s-1 and an age of ≃105 years for the H ii region. Our analysis shows that the UV and infrared dust opacities in the H ii region and the PDR are a factor 5 to 10 lower than in the diffuse interstellar medium. In the ionized gas, Lyα photons are a major source of dust heating at distances larger than ≃0.06 pc from θ 1 Ori C. Dust temperatures can be explained if the size of the grains is between 0.1 and 1 μm. We derive the photoelectric heating efficiency of the atomic gas in the Orion bar. The results are in good qualitative agreement with models and the quantitative differences indicate a decreased polycyclic aromatic hydrocarbon abundance in this region.

  9. Turmoil in Orion: The Nearest Massive Protostar

    CERN Document Server

    Tan, Jonathan C

    2008-01-01

    I discuss different theories of massive star formation: formation from massive cores, competitive Bondi-Hoyle accretion, and protostellar collisions. I summarize basic features of the Turbulent Core Model (TCM). I then introduce the Orion Kleinmann-Low (KL) region, embedded in the Orion Nebula Cluster (ONC) and one of the nearest regions of massive star formation. The KL region contains three principal radio sources, known as "I", "n" and "BN". BN is known to be a runaway star, almost certainly set in motion by dynamical ejection within the ONC from a multiple system of massive stars, that would leave behind a recoiling, hard, massive, probably eccentric binary. I review the debate about whether this binary is Theta^1C, the most massive star in the ONC, or source "I", and argue that it is most likely to be Theta^1C, since this is now known be a recoiling, hard, massive, eccentric binary, with properties that satisfy the energy and momentum constraints implied by BN's motion. Source "n" is a relatively low-mas...

  10. N2H+ and HC3N Observations of the Orion A Cloud

    CERN Document Server

    Tatematsu, K; Umemoto, T; Sekimoto, Y

    2008-01-01

    The ``integral-shaped filament'' of the Orion A giant molecular cloud was mapped in N2H+, and its northern end, the OMC-2/3 region was observed also in HC3N and CCS. The N2H+ distribution is similar to the dust continuum distribution, except for the central part of the Orion Nebula. The distribution of H13CO+ holds resemblance to that of dust continuum, but the N2H+ distribution looks more similar to dust continuum distribution. The N-bearing molecules, N2H+ and NH3 seem to be more intense in OMC-2, compared with the H13CO+ and CS distribution. We identified 34 cloud cores from N2H+ data. Over the Orion Nebula region, the N2H+ linewidth is large (1.1-2.1 km/s). In the OMC-2/3 region, it becomes moderate (0.5-1.3 km/s), and it is smaller (0.3-1.1 km/s) in the south of the Orion Nebula. On the other hand, the gas kinetic temperature of the quiescent cores observed in N2H+ is rather constant (~ 20 K) over the $\\int$-shaped filament. We detected no CCS emission in the OMC-2/3 region. In general, N2H+ and HC3N dis...

  11. The Orion Molecular Cloud 2/3 and NGC 1977 Regions

    CERN Document Server

    Peterson, Dawn E

    2008-01-01

    The Orion Molecular Cloud 2/3 region (hereafter, OMC-2/3) and the reflection nebula NGC 1977 encompass a section of the Orion A molecular cloud undergoing vigorous star forming activity. One of the richest assemblages of protostars in the nearest 500 pc is seen in OMC-2/3, while NGC 1977 contains a cluster of over 100 young stars. In this review, we present a census of the protostars, pre-main sequence stars, and young brown dwarfs in these regions. These are identified through sub-millimeter surveys, far-red to near-infrared imaging and spectroscopy with ground-based telescopes, mid-infrared photometry from the Spitzer Space Telescope, and X-ray observations made with the Chandra X-ray Observatory. We present an overview of the distribution of molecular gas associated with these regions and the rich complex of shock heated nebulae created by the young stars interacting with the molecular gas. Finally, we discuss the relationship of OMC-2/3 and NGC 1977 to the neighboring Orion Nebula Cluster and the Orion OB...

  12. DEUTERATED MOLECULES IN ORION KL FROM HERSCHEL/HIFI

    Energy Technology Data Exchange (ETDEWEB)

    Neill, Justin L.; Crockett, Nathan R.; Bergin, Edwin A. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Pearson, John C. [Jet Propulsion Laboratory, Caltech, Pasadena, CA 91109 (United States); Xu, Li-Hong, E-mail: jneill@umich.edu [Department of Physics, Centre for Laser, Atomic, and Molecular Studies (CLAMS), University of New Brunswick, Saint John, New Brunswick E2L 4L5 (Canada)

    2013-11-10

    We present a comprehensive study of the deuterated molecules detected in the fullband HIFI survey of the Orion Kleinmann-Low nebula (Orion KL) region. Ammonia, formaldehyde, and methanol and their singly deuterated isotopologues are each detected through numerous transitions in this survey with a wide range in optical depths and excitation conditions. In conjunction with a recent study of the abundance of HDO and H{sub 2}O in Orion KL, this study yields the best constraints on deuterium fractionation in an interstellar molecular cloud to date. As previous studies have found, both the Hot Core and Compact Ridge regions within Orion KL contain significant abundances of deuterated molecules, suggesting an origin in cold grain mantles. In the Hot Core, we find that ammonia is roughly a factor of two more fractionated than water. In the Compact Ridge, meanwhile, we find similar deuterium fractionation in water, formaldehyde, and methanol, with D/H ratios of (2-8) × 10{sup –3}. The [CH{sub 2}DOH]/[CH{sub 3}OD] ratio in the Compact Ridge is found to be 1.2 ± 0.3. The Hot Core generally has lower deuterium fractionation than the Compact Ridge, suggesting a slightly warmer origin, or a greater contribution from warm gas phase chemistry.

  13. Hubble's diagram and cosmic expansion

    OpenAIRE

    Kirshner, Robert P.

    2003-01-01

    Edwin Hubble's classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168–173]. The chief result, that a galaxy's distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble's Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble's distances have a large systematic error, Hubble's velo...

  14. Hubble's diagram and cosmic expansion

    OpenAIRE

    Kirshner, Robert P.

    2003-01-01

    Edwin Hubble's classic article on the expanding universe appeared in PNAS in 1929 [Hubble, E. P. (1929) Proc. Natl. Acad. Sci. USA 15, 168–173]. The chief result, that a galaxy's distance is proportional to its redshift, is so well known and so deeply embedded into the language of astronomy through the Hubble diagram, the Hubble constant, Hubble's Law, and the Hubble time, that the article itself is rarely referenced. Even though Hubble's distances have a large systematic error, Hubble's velo...

  15. Discovery of a Circumstellar Disk in the Lagoon Nebula

    Science.gov (United States)

    1997-04-01

    Circumstellar disks of gas and dust play a crucial role in the formation of stars and planets. Until now, high-resolution images of such disks around young stars within the Orion Nebula obtained with the Hubble Space Telescope (HST) constituted the most direct proof of their existence. Now, another circumstellar disk has been detected around a star in the Lagoon Nebula - also known as Messier 8 (M8) , a giant complex of interstellar gas and dust with many young stars in the southern constellation of Sagittarius and four times more distant than the Orion Nebula. The observations were carried out by an international team of scientists led by Bringfried Stecklum (Thüringer Landessternwarte, Tautenburg, Germany) [1] who used telescopes located at the ESO La Silla observatory and also observations from the HST archive. These new results are paving the road towards exciting research programmes on star formation which will become possible with the ESO Very Large Telescope. The harsh environment of circumstellar disks The existence of circumstellar disks has been inferred from indirect measurements of young stellar objects, such as the spectral energy distribution, the analysis of the profiles of individual spectral lines and measurements of the polarisation of the emitted light [2]. Impressive images of such disks in the Orion Nebula, known as proplyds (PROto-PLanetarY DiskS), have been obtained by the HST during the recent years. They have confirmed the interpretation of previous ground-based emission-line observations and mapping by radio telescopes. Moreover, they demonstrated that those disks which are located close to hot and massive stars are subject to heating caused by the intense radiation from these stars. Subsequently, the disks evaporate releasing neutral gas which streams off. During this process, shock fronts (regions with increased density) with tails of ionised gas result at a certain distance between the disk and the hot star. These objects appear on

  16. Dusty globules in the Crab Nebula

    Science.gov (United States)

    Grenman, T.; Gahm, G. F.; Elfgren, E.

    2017-03-01

    Context. Dust grains are widespread in the Crab Nebula. A number of small, dusty globules, are visible as dark spots against the background of continuous synchrotron emission in optical images. Aims: Our aim is to catalogue such dusty globules and investigate their properties. Methods: From existing broad-band images obtained with the Hubble Space Telescope, we located 92 globules, for which we derived positions, dimensions, orientations, extinctions, masses, proper motions, and their distributions. Results: The globules have mean radii ranging from 400 to 2000 AU and are not resolved in current infrared images of the nebula. The extinction law for dust grains in these globules matches a normal interstellar extinction law. Derived masses of dust range from 1 to 60 × 10-6M⊙, and the total mass contained in globules constitute a fraction of approximately 2% or less of the total dust content of the nebula. The globules are spread over the outer part of the nebula, and a fraction of them coincide in position with emission filaments, where we find elongated globules that are aligned with these filaments. Only 10% of the globules are coincident in position with the numerous H2-emitting knots found in previous studies. All globules move outwards from the centre with transversal velocities of 60 to 1600 km s-1, along with the general expansion of the remnant. We discuss various hypotheses for the formation of globules in the Crab Nebula. Based on observations collected with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute.

  17. The Orion Molecular Cloud 2/3 and NGC 1977 Regions

    OpenAIRE

    Peterson, Dawn E.; Megeath, Tom

    2008-01-01

    The Orion Molecular Cloud 2/3 region (hereafter, OMC-2/3) and the reflection nebula NGC 1977 encompass a section of the Orion A molecular cloud undergoing vigorous star forming activity. One of the richest assemblages of protostars in the nearest 500 pc is seen in OMC-2/3, while NGC 1977 contains a cluster of over 100 young stars. In this review, we present a census of the protostars, pre-main sequence stars, and young brown dwarfs in these regions. These are identified through sub-millimeter...

  18. The orion nebula: an elephant for the blind

    Directory of Open Access Journals (Sweden)

    C. R. O`Dell

    2001-01-01

    Full Text Available Se presentan resultados preliminares del an alisis de datos espectrosc opicos de alta resoluci on de una muestra de nebulosas planetarias con n ucleo WR o estrellas con l neas en emisi on d ebiles. Se han seleccionado objetos con estrellas centrales de diversas caracter sticas WR. Para todos los objetos, se han calculado las densidades y temperaturas electr onicas as como la composici on qu mica y la velocidad de expansi on del gas. Los resultados se usan para realizar un estudio estad stico buscando relaciones entre los par ametros estelares y nebulares y el efecto del viento de la estrella WR en la nebulosa planetaria.

  19. Outflows, jets and shocks in the orion nebula

    Directory of Open Access Journals (Sweden)

    C. R. O`Dell

    2000-01-01

    Full Text Available El c umulo de estrellas j ovenes asociadas a la Nebulosa de Ori on es un buen laboratorio para el estudio de los plasmas. Vemos cinco tipos de ujos y choques. Los ujos de foto-ablaci on de los proplyds m as cercanos a 1Ori C forman choques cuasi estacionarios con el viento de la estrella. Se observan micro-chorros con escalas menores a 103 AU en 20 estrellas peque~nas. Los chorros aislados, con altas velocidades y escalas cercanas a 104 AU, son comunes pero menos numerosos. Tambi en se ven choques cuando los chorros golpean al gas nebular ionizado o al gas neutro del fondo. El tipo de objeto nal es el choque estacionario formado por la interacci on del viento estelar, generado durante la formaci on del disco, con el gas ambiental que uye hacia afuera de la nebulosa.

  20. Fluorescence of permitted lines in the orion nebula

    Directory of Open Access Journals (Sweden)

    Vladimir Escalante

    2002-01-01

    Full Text Available El espectro de emisi on de N II se compar o con observaciones recientes de l neas permitidas en emisi on en la nebulosa de Ori on. Los ajustes de modelos nebulares a los datos muestran coincidencias cualitativas con un espectro excitado por uorescencia de absorci on de luz estelar, pero hay grandes discrepancias con las intensidades observadas en muchos casos.

  1. Density gradients and internal dust in the Orion nebula

    Directory of Open Access Journals (Sweden)

    Luc Binette

    2002-01-01

    Full Text Available La estructura de ionización de la nebulosa de Orión puede ser descrita como una piel delgada sobre la superficie de una nube densa. Proponemos que una estratificación en la densidad, descrita por una ley de potencias (n / x_2, donde x es la distancia al frente de ionización, presenta propiedades que concuerdan con nuestros espectros de rendija larga de la nebulosa de Orión. Por ejemplo, existe una relación de unicidad entre el brillo superficial en HB, o la densidad del frente de ionización en [S II], y la escala L de la ley de potencias, donde L es la distancia entre el frente de ionización y el lugar donde comienza a crecer la densidad, cerca de la estrella excitadora. Es necesario incluir polvo interno a fin de obtener un ajuste aceptable a las observaciones tanto de la densidad del [S II], como del brillo superficial en HB. Los modelos que incluyen granos de polvo pequeños proporcionan un mejor ajuste que aquellos con granos grandes. Los gradientes de los cocientes de líneas observados a lo largo de la rendija se reproducen cualitativamente por nuestros modelos de densidad estratificada, suponiendo una temperatura estelar de 38,000 K. La desexcitación colisional parece ser la responsable de la mitad del gradiente observado en el cociente [N II] 5755/[N II] 6583, el cual es sensible a la temperatura. Proponemos que la relación empírica encontrada por Wen & O`Dell (1995 entre la densidad y la distancia a la estrella puede deberse a una estratificación de la densidad en forma de ley de potencias.

  2. INTERNAL PROPER MOTIONS IN THE ESKIMO NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    García-Díaz, Ma. T.; Gutiérrez, L.; Steffen, W.; López, J. A. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Km 103 Carretera Tijuana-Ensenada, 22860 Ensenada, B.C. (Mexico); Beckman, J., E-mail: tere@astro.unam.mx, E-mail: leonel@astro.unam.mx, E-mail: wsteffen@astro.unam.mx, E-mail: jal@astro.unam.mx, E-mail: jeb@iac.es [Instituto de Astrofísica de Canarias, La Laguna, Tenerife (Spain)

    2015-01-10

    We present measurements of internal proper motions at more than 500 positions of NGC 2392, the Eskimo Nebula, based on images acquired with WFPC2 on board the Hubble Space Telescope at two epochs separated by 7.695 yr. Comparisons of the two observations clearly show the expansion of the nebula. We measured the amplitude and direction of the motion of local structures in the nebula by determining their relative shift during that interval. In order to assess the potential uncertainties in the determination of proper motions in this object, in general, the measurements were performed using two different methods, used previously in the literature. We compare the results from the two methods, and to perform the scientific analysis of the results we choose one, the cross-correlation method, because it is more reliable. We go on to perform a ''criss-cross'' mapping analysis on the proper motion vectors, which helps in the interpretation of the velocity pattern. By combining our results of the proper motions with radial velocity measurements obtained from high resolution spectroscopic observations, and employing an existing 3D model, we estimate the distance to the nebula to be 1.3 kpc.

  3. Observing by hand sketching the nebulae in the nineteenth century

    CERN Document Server

    Nasim, Omar W

    2014-01-01

    Today we are all familiar with the iconic pictures of the nebulae produced by the Hubble Space Telescope's digital cameras. But there was a time, before the successful application of photography to the heavens, in which scientists had to rely on handmade drawings of these mysterious phenomena.           Observing by Hand sheds entirely new light on the ways in which the production and reception of handdrawn images of the nebulae in the nineteenth century contributed to astronomical observation. Omar W. Nasim investigates hundreds of unpublished observing books and paper records from six ninete

  4. Hubble Deep Fields

    Science.gov (United States)

    Ferguson, H.; Murdin, P.

    2000-11-01

    The Hubble Deep Fields are two small areas of the sky that were carefully selected for deep observations by the HUBBLE SPACE TELESCOPE (HST). They represent the deepest optical observations to date and reveal galaxies as faint as V=30, 4 billion times fainter than can be seen with the unaided eye....

  5. Orion Emergency Mask Approach

    Science.gov (United States)

    Tuan, George C.; Graf, John C.

    2009-01-01

    Emergency mask approach on Orion poses a challenge to the traditional Shuttle or Station approaches. Currently, in the case of a fire or toxic spill event, the crew utilizes open loop oxygen masks that provide the crew with oxygen to breath, but also dumps the exhaled oxygen into the cabin. For Orion, with a small cabin volume, the extra oxygen will exceed the flammability limit within a short period of time, unless a nitrogen purge is also provided. Another approach to a fire or toxic spill event is the use of a filtering emergency masks. These masks utilize some form of chemical beds to scrub the air clean of toxic providing the crew safe breathing air for a period without elevating the oxygen level in the cabin. Using the masks and a form of smoke-eater filter, it may be possible to clean the cabin completely or to a level for safe transition to a space suit to perform a cabin purge. Issues with filters in the past have been the reaction time, breakthroughs, and high breathing resistance. Development in a new form of chemical filters has shown promise to make the filtering approach feasible.

  6. Orion Script Generator

    Science.gov (United States)

    Dooling, Robert J.

    2012-01-01

    NASA Engineering's Orion Script Generator (OSG) is a program designed to run on Exploration Flight Test One Software. The script generator creates a SuperScript file that, when run, accepts the filename for a listing of Compact Unique Identifiers (CUIs). These CUIs will correspond to different variables on the Orion spacecraft, such as the temperature of a component X, the active or inactive status of another component Y, and so on. OSG will use a linked database to retrieve the value for each CUI, such as "100 05," "True," and so on. Finally, OSG writes SuperScript code to display each of these variables before outputting the ssi file that allows recipients to view a graphical representation of Orion Flight Test One's status through these variables. This project's main challenge was creating flexible software that accepts and transfers many types of data, from Boolean (true or false) values to "Unsigned Long Long'' values (any number from 0 to 18,446,744,073,709,551,615). We also needed to allow bit manipulation for each variable, requiring us to program functions that could convert any of the multiple types of data into binary code. Throughout the project, we explored different methods to optimize the speed of working with the CUI database and long binary numbers. For example, the program handled extended binary numbers much more efficiently when we stored them as collections of Boolean values (true or false representing 1 or 0) instead of as collections of character strings or numbers. We also strove to make OSG as user-friendly and accommodating of different needs as possible its default behavior is to display a current CUI's maximum value and minimum value with three to five intermediate values in between, all in descending order. Fortunately, users can also add other input on the same lines as each CUI name to request different high values, low values, display options (ascending, sine, and so on), and interval sizes for generating intermediate values

  7. VISION - Vienna survey in orion : I. VISTA orion A survey

    OpenAIRE

    Meingast, S.; Alves,J.; Mardones, D.; Teixeira, P. S.; Lombardi, M.; Großschedl, J.; Ascenso, J.; Bouy, H.; Forbrich, J.; Goodman, A; Hacar, A.; Hasenberger, B.; Kainulainen, J.; Kubiak, K.; Lada, C.

    2016-01-01

    Orion A hosts the nearest massive star factory, thus offering a unique opportunity to resolve the processes connected with the formation of both low- and high-mass stars. Here we present the most detailed and sensitive near-infrared (NIR) observations of the entire molecular cloud to date. With the unique combination of high image quality, survey coverage, and sensitivity, our NIR survey of Orion A aims at establishing a solid empirical foundation for further studies of this important cloud. ...

  8. Planetary nebulae as tracers of galaxy stellar populations

    OpenAIRE

    A. Buzzoni; Arnaboldi, M.; Corradi, R.L.M.

    2006-01-01

    We address the general problem of the luminosity-specific planetary nebula (PN) number, defined as alpha = N(PN)/L(gal), and its relationship with age and metallicity of the parent stellar population. Our analysis relies on population synthesis models for simple stellar populations and more elaborated galaxy models along the full star-formation range of the Hubble morphological sequence. This theoretical framework is compared with the updated census of the PN population in Local Group galaxie...

  9. ORiON: Editorial Policies

    African Journals Online (AJOL)

    Papers in the following categories are typically published in ORiON: Development of New Theory, which may be useful to operations research practitioners, ... OR in Banking, applied OR modelling, applied statistical modelling, multivariate ...

  10. The Ionized Nebula surrounding the Red Supergiant W26 in Westerlund 1

    CERN Document Server

    Wright, Nicholas J; Drew, Janet E; Barentsen, Geert; Barlow, Michael J; Walsh, Jeremy R; Zijlstra, Albert; Drake, Jeremy J; Eisloffel, Jochen; Farnhill, Hywel J

    2013-01-01

    We present H\\alpha images of an ionized nebula surrounding the M2-5Ia red supergiant (RSG) W26 in the massive star cluster Westerlund 1. The nebula consists of a circumstellar shell or ring ~0.1pc in diameter and a triangular nebula ~0.2pc from the star that in high-resolution Hubble Space Telescope images shows a complex filamentary structure. The excitation mechanism of both regions is unclear since RSGs are too cool to produce ionizing photons and we consider various possibilities. The presence of the nebula, high stellar luminosity and spectral variability suggest that W26 is a highly evolved RSG experiencing extreme levels of mass-loss. As the only known example of an ionized nebula surrounding a RSG W26 deserves further attention to improve our understanding of the final evolutionary stages of massive stars.

  11. The Hubble effective potential

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, T.M.; Miao, S.P.; Prokopec, T. [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, Leuvenlaan 4, Postbus 80.195, 3508 TD Utrecht (Netherlands); Woodard, R.P., E-mail: T.M.Janssen@uu.nl, E-mail: S.Miao@uu.nl, E-mail: T.Prokopec@uu.nl, E-mail: woodard@phys.ufl.edu [Department of Physics, University of Florida, Gainesville, FL 32611 (United States)

    2009-05-15

    We generalize the effective potential to scalar field configurations which are proportional to the Hubble parameter of a homogeneous and isotropic background geometry. This may be useful in situations for which curvature effects are significant. We evaluate the one loop contribution to the Hubble Effective Potential for a massless scalar with arbitrary conformal and quartic couplings, on a background for which the deceleration parameter is constant. Among other things, we find that inflationary particle production leads to symmetry restoration at late times.

  12. Illuminating gas inflows/outflows in the MUSE deepest fields : Lyα nebulae around forming galaxies at z ≃ 3.3

    NARCIS (Netherlands)

    Vanzella, E.; Balestra, I.; Gronke, M.; Karman, W.; Caminha, G. B.; Dijkstra, M.; Rosati, P.; De Barros, S.; Caputi, K.; Grillo, C.; Tozzi, P.; Meneghetti, M.; Mercurio, A.; Gilli, R.

    2017-01-01

    We report on the discovery of extended Ly-alpha nebulae at z~3.3 in the Hubble Ultra Deep Field (HUDF, ~ 40 kpc X 80 kpc) and behind the Hubble Frontier Fields galaxy cluster MACSJ0416 (~ 40kpc), spatially associated with groups of star-forming galaxies. VLT/MUSE integral field spectroscopy reveals

  13. Dusty globules in the Crab Nebula

    CERN Document Server

    Grenman, Tiia; Elfgren, Erik

    2016-01-01

    From existing broad-band images obtained with the Hubble Space Telescope, we located 92 globules, for which we derived positions, dimensions, orientations, extinctions, masses, proper motions, and their distributions. The globules have mean radii ranging from 400 to 2000 AU and are not resolved in current infrared images of the nebula. The extinction law for dust grains in these globules matches a normal interstellar extinction law. Derived masses of dust range from 1 to 60 x 10^(-6) solar masses, and the total mass contained in globules constitute a fraction of approximately 2% or less of the total dust content of the nebula. The globules are spread over the outer part of the nebula, and a fraction of them coincide in position with emission filaments, where we find elongated globules that are aligned with these filaments. Only 10% of the globules are coincident in position with the numerous H2-emitting knots found in previous studies. All globules move outwards from the centre with transversal velocities of ...

  14. VISION - Vienna survey in Orion. I. VISTA Orion A Survey

    Science.gov (United States)

    Meingast, Stefan; Alves, João; Mardones, Diego; Teixeira, Paula Stella; Lombardi, Marco; Großschedl, Josefa; Ascenso, Joana; Bouy, Herve; Forbrich, Jan; Goodman, Alyssa; Hacar, Alvaro; Hasenberger, Birgit; Kainulainen, Jouni; Kubiak, Karolina; Lada, Charles; Lada, Elizabeth; Moitinho, André; Petr-Gotzens, Monika; Rodrigues, Lara; Román-Zúñiga, Carlos G.

    2016-03-01

    Context. Orion A hosts the nearest massive star factory, thus offering a unique opportunity to resolve the processes connected with the formation of both low- and high-mass stars. Here we present the most detailed and sensitive near-infrared (NIR) observations of the entire molecular cloud to date. Aims: With the unique combination of high image quality, survey coverage, and sensitivity, our NIR survey of Orion A aims at establishing a solid empirical foundation for further studies of this important cloud. In this first paper we present the observations, data reduction, and source catalog generation. To demonstrate the data quality, we present a first application of our catalog to estimate the number of stars currently forming inside Orion A and to verify the existence of a more evolved young foreground population. Methods: We used the European Southern Observatory's (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) to survey the entire Orion A molecular cloud in the NIR J,H, and KS bands, covering a total of ~18.3 deg2. We implemented all data reduction recipes independently of the ESO pipeline. Estimates of the young populations toward Orion A are derived via the KS-band luminosity function. Results: Our catalog (799 995 sources) increases the source counts compared to the Two Micron All Sky Survey by about an order of magnitude. The 90% completeness limits are 20.4, 19.9, and 19.0 mag in J,H, and KS, respectively. The reduced images have 20% better resolution on average compared to pipeline products. We find between 2300 and 3000 embedded objects in Orion A and confirm that there is an extended foreground population above the Galactic field, in agreement with previous work. Conclusions: The Orion A VISTA catalog represents the most detailed NIR view of the nearest massive star-forming region and provides a fundamental basis for future studies of star formation processes toward Orion. Based on observations made with ESO Telescopes at the La Silla

  15. HUBBLE WATCHES STAR TEAR APART ITS NEIGHBORHOOD

    Science.gov (United States)

    2002-01-01

    NASA's Hubble Space Telescope has snapped a view of a stellar demolition zone in our Milky Way Galaxy: a massive star, nearing the end of its life, tearing apart the shell of surrounding material it blew off 250,000 years ago with its strong stellar wind. The shell of material, dubbed the Crescent Nebula (NGC 6888), surrounds the 'hefty,' aging star WR 136, an extremely rare and short-lived class of super-hot star called a Wolf-Rayet. Hubble's multicolored picture reveals with unprecedented clarity that the shell of matter is a network of filaments and dense knots, all enshrouded in a thin 'skin' of gas [seen in blue]. The whole structure looks like oatmeal trapped inside a balloon. The skin is glowing because it is being blasted by ultraviolet light from WR 136. Hubble's view covers a small region at the northeast tip of the structure, which is roughly three light-years across. A picture taken by a ground-based telescope [lower right] shows almost the entire nebula. The whole structure is about 16 light-years wide and 25 light-years long. The bright dot near the center of NGC 6888 is WR 136. The white outline in the upper left-hand corner represents Hubble's view. Hubble's sharp vision is allowing scientists to probe the intricate details of this complex system, which is crucial to understanding the life cycle of stars and their impact on the evolution of our galaxy. The results of this study appear in the June issue of the Astronomical Journal. WR 136 created this web of luminous material during the late stages of its life. As a bloated, red super-giant, WR 136 gently puffed away some of its bulk, which settled around it. When the star passed from a super-giant to a Wolf-Rayet, it developed a fierce stellar wind - a stream of charged particles released from its surface - and began expelling mass at a furious rate. The star began ejecting material at a speed of 3.8 million mph (6.1 million kilometers per hour), losing matter equal to that of our Sun's every 10

  16. Unraveling the Evolution of Protostars in Diverse Environments: The Herschel Orion Protostar Survey

    Science.gov (United States)

    Megeath, S. Thomas; the Herschel Orion Protostar Survey Team

    2014-01-01

    The Herschel Orion Protostar Survey (HOPS), a 200 hour PACS imaging and spectroscopy OTKP, is the cornerstone of a large multi-observatory campaign combining Herschel data with observations from Spitzer,Hubble, APEX, and other facilities. HOPS has produced well sampled 1-870 micron SEDs of over 300 protostars in the Orion molecular clouds, the most extensive such survey of a single cloud complex to date, and has obtained PACS spectra of 36 protostars to observe line emission from CO, OH, and H2O. We will present the major HOPS discoveries that demonstrate Herschel's contributions to an emerging picture of protostellar evolution within the diverse environments of the Orion A & B molecular clouds. Among these, the HOPS team has discovered protostars undetected by Spitzer that appear to be the youngest protostars in Orion (Stutz et al. 2013). We have found that the luminosities of high-J CO lines are correlated with protostellar luminosities, but the excitation temperatures are not, indicating that these lines form in high-temperature gas within outflows (Manoj et al. 2013). We have also constructed and modeled the first 1-70 um SED of a protostellar FU Ori object before and after its outburst, finding an atypically low post-outburst luminosity (Fischer et al. 2012). Finally, we have identified systematic variations in the spacing and luminosity of protostars between the different environments found in Orion (Megeath, Stanke, in prep.). More generally, the HOPS team is now determining the fundamental protostellar properties (envelope mass and density, system luminosity, and outflow cavity geometry) of the 300 Orion protostars by a comparison of the SEDs to radiative transfer models. We will summarize the prospects of using these fundamental properties to construct a detailed sequence for the physical evolution of protostars as they dissipate their envelopes, accounting for the influence of the diverse environments found within Orion.

  17. Waves on the surface of the Orion molecular cloud.

    Science.gov (United States)

    Berné, Olivier; Marcelino, Núria; Cernicharo, José

    2010-08-19

    Massive stars influence their parental molecular cloud, and it has long been suspected that the development of hydrodynamical instabilities can compress or fragment the cloud. Identifying such instabilities has proved difficult. It has been suggested that elongated structures (such as the 'pillars of creation') and other shapes arise because of instabilities, but alternative explanations are available. One key signature of an instability is a wave-like structure in the gas, which has hitherto not been seen. Here we report the presence of 'waves' at the surface of the Orion molecular cloud near where massive stars are forming. The waves seem to be a Kelvin-Helmholtz instability that arises during the expansion of the nebula as gas heated and ionized by massive stars is blown over pre-existing molecular gas.

  18. Hubble Camera Resumes Science Operation With Picture Of 'Butterfly' In Space.

    Science.gov (United States)

    2002-01-01

    he Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) is back at work, capturing this black-and-white image of the 'butterfly wing'-shaped nebula, NGC 2346. The nebula is about 2,000 light-years away from Earth in the direction of the constellation Monoceros. It represents the spectacular 'last gasp' of a binary star system at the nebula's center. The image was taken on March 6, as part of the recommissioning of the Hubble Space Telescope's previously installed scientific instruments following the successful servicing of the HST by NASA astronauts in February. WFPC2 was installed in HST during the servicing mission in 1993. At the center of the nebula lies a pair of stars that are so close together that they orbit around each other every 16 days. This is so close that, even with Hubble, the pair of stars cannot be resolved into its two components. One component of this binary is the hot core of a star that has ejected most of its outer layers, producing the surrounding nebula. Astronomers believe that this star, when it evolved and expanded to become a red giant, actually swallowed its companion star in an act of stellar cannibalism. The resulting interaction led to a spiraling together of the two stars, culminating in ejection of the outer layers of the red giant. Most of the outer layers were ejected into a dense disk, which can still be seen in the Hubble image, surrounding the central star. Later the hot star developed a fast stellar wind. This wind, blowing out into the surrounding disk, has inflated the large, wispy hourglass-shaped wings perpendicular to the disk. These wings produce the butterfly appearance when seen in projection. The total diameter of the nebula is about one-third of a light-year, or 2 trillion miles. Our own Sun will eject a nebula about 5 billion years from now. However, the Sun is not a double star, so its nebula may well be more spherical in shape. The image was taken through a filter that shows the light of glowing

  19. Hubble Camera Resumes Science Operation With Picture Of 'Butterfly' In Space.

    Science.gov (United States)

    2002-01-01

    he Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2) is back at work, capturing this black-and-white image of the 'butterfly wing'-shaped nebula, NGC 2346. The nebula is about 2,000 light-years away from Earth in the direction of the constellation Monoceros. It represents the spectacular 'last gasp' of a binary star system at the nebula's center. The image was taken on March 6, as part of the recommissioning of the Hubble Space Telescope's previously installed scientific instruments following the successful servicing of the HST by NASA astronauts in February. WFPC2 was installed in HST during the servicing mission in 1993. At the center of the nebula lies a pair of stars that are so close together that they orbit around each other every 16 days. This is so close that, even with Hubble, the pair of stars cannot be resolved into its two components. One component of this binary is the hot core of a star that has ejected most of its outer layers, producing the surrounding nebula. Astronomers believe that this star, when it evolved and expanded to become a red giant, actually swallowed its companion star in an act of stellar cannibalism. The resulting interaction led to a spiraling together of the two stars, culminating in ejection of the outer layers of the red giant. Most of the outer layers were ejected into a dense disk, which can still be seen in the Hubble image, surrounding the central star. Later the hot star developed a fast stellar wind. This wind, blowing out into the surrounding disk, has inflated the large, wispy hourglass-shaped wings perpendicular to the disk. These wings produce the butterfly appearance when seen in projection. The total diameter of the nebula is about one-third of a light-year, or 2 trillion miles. Our own Sun will eject a nebula about 5 billion years from now. However, the Sun is not a double star, so its nebula may well be more spherical in shape. The image was taken through a filter that shows the light of glowing

  20. Hubble's Nobel Prize

    CERN Document Server

    Soares, D S L

    2001-01-01

    Astronomy is not in the list of natural sciences aimed at by the Nobel awards. In spite of that, there were, throughout the 1930s until the early 1950s, effective moves by important scientists to distinguish Hubble with the Prize. A short report on these attempts is made as well as speculation on what would be the citation for the prize in view of the broad range of Hubble's scientific achievements. Within this context, the opportunity is also taken for publicizing the Crafoord Prize which does consider astronomy.

  1. Did Edwin Hubble plagiarize?

    CERN Document Server

    Shaviv, Giora

    2011-01-01

    Recently Block published an astro-ph [arXiv:1106.3928 (2011)] insinuating that Hubble censored a prior publication of his famous and seminal discovery of the expansion of the universe. This issue was investigated by us in detail as part of the book: The Quest for Chemical Element Genesis and What the Chemical Elements Tell about the Universe (Accepted for publication, Springer Pub. Heidelberg, 2011.) Since the book is due in few months, we extract here the relevant parts. Our summary: We exonerate Hubble from the charge that he censored or ignored or plagiarized Lemaitre's earlier theoretical discovery.

  2. The Star Formation History of Orion and its Environs

    Science.gov (United States)

    Calvet, Nuria

    2004-01-01

    During this period of performance, we have obtained the following observations and carried out the analysis of the Orion associations itemized below. 1. Quest Optical Photometry: The photometric survey carries out with the Quest camera is finished. The strips at declinations +1 degree and -1 degree have already been processed. Photometry for a total of around 400,000 stars was obtained in these two strips with the Quest camera pipeline. Around 24,000 variables were picked out of this total by our variability software. Of these, around 2,500 stars fall above the main sequence and so were picked as candidates for spectroscopic follow-up. 2. Slit spectroscopy of bright candidates: Spectra for some 800 candidate PMS stars were obtained with the FAST spectrograph at the SAO 1.5m telescope in Mt. Hopkins. The spectra are being analyzed; 300 stars have been confirmed as young. 3. Multifiber spectroscopy: The first test of the multifiber spectrograph Hectoechelle were carried out in December 2003. One field of the Orion Nebula Cluster was observed with Hectochelle at three wavelength settings. A total of 157 spectra were obtained. Of these, 63 stars have been confirmed as Classical T Tauri stars, and 36 additional stars need further follow up. A paper is in preparation. 4. UBVRI photometry: We were granted time with the 4-shooter CCD Mosaic Camera at the SAO 1.2m telescope, to obtain UBVRI photometry of a subset of 53 newly identified T Tauri stars in the strips centered at DEC=-1 and +l. This sample is composed of strong Halpha emitting PMS stars (Classical T Tauri stars) located mostly in the Orion OB l b association, around the Orion Belt area. We have estimated mass accretion rates for 22 for these stars using the U photometry and the calibration of Gullbring et al. (1998), and found it to be similar to that of young stars in associations of similar age. 5. Near and mid-IR photometry: During the winter of 2003, we used the IR Camera on the SAO 1.2m telescope, to obtain

  3. VISION - Vienna survey in Orion I. VISTA Orion A Survey

    CERN Document Server

    Meingast, Stefan; Mardones, Diego; Teixeira, Paula; Lombardi, Marco; Großschedl, Josefa; Ascenso, Joana; Bouy, Herve; Forbrich, Jan; Goodman, Alyssa; Hacar, Alvaro; Hasenberger, Birgit; Kainulainen, Jouni; Kubiak, Karolina; Lada, Charles; Lada, Elizabeth; Moitinho, André; Petr-Gotzens, Monika; Rodrigues, Lara; Román-Zúñiga, Carlos G

    2016-01-01

    Orion A hosts the nearest massive star factory, thus offering a unique opportunity to resolve the processes connected with the formation of both low- and high-mass stars. Here we present the most detailed and sensitive near-infrared (NIR) observations of the entire molecular cloud to date. With the unique combination of high image quality, survey coverage, and sensitivity, our NIR survey of Orion A aims at establishing a solid empirical foundation for further studies of this important cloud. In this first paper we present the observations, data reduction, and source catalog generation. To demonstrate the data quality, we present a first application of our catalog to estimate the number of stars currently forming inside Orion A and to verify the existence of a more evolved young foreground population. We used the European Southern Observatory's (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) to survey the entire Orion A molecular cloud in the NIR $J, H$, and $K_S$ bands, covering a total of $...

  4. Photoevaporation and spatial variation of grain sizes in Orion 114-426

    CERN Document Server

    Miotello, Anna; Potenza, Marco A C; Ricci, Luca

    2012-01-01

    Deep HST broad-band images taken with ACS and WFPC2 of the giant ($\\sim 1000$ AU diameter) dark silhouette proplyd 114-426 in the Orion Nebula show that this system is tilted, asymmetric, warped and photoevaporated. The exquisite angular resolution of ACS allows us to map the distribution of dust grains at the northern translucent edge of the disk, dominated by the photoevaporative flow. Using the Mie theory for standard circumstellar disk grains, we find evidence for a spatial gradient in grain size. The typical dust radius, $\\simeq 0.2-0.7 \\mu$m (less than what reported by previous studies) becomes smaller as the distance from the disk center increases, consistent with the expectations for the dynamic of dust entrained in a gaseous photoevaporative wind. Our analysis of the disk morphology and location within the nebula indicates that this system is photoevaporated by the diffuse radiation field of the Orion Nebula, while being shielded from the radiation coming directly from the central Trapezium stars. We...

  5. HOPS 383: AN OUTBURSTING CLASS 0 PROTOSTAR IN ORION

    Energy Technology Data Exchange (ETDEWEB)

    Safron, Emily J.; Megeath, S. Thomas; Booker, Joseph [Ritter Astrophysical Observatory, Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States); Fischer, William J. [NASA Goddard Space Flight Center, Greenbelt, MD (United States); Furlan, Elise; Rebull, Luisa M. [Infrared Processing and Analysis Center, Caltech, Pasadena, CA (United States); Stutz, Amelia M. [Max-Planck-Institut für Astronomie, Heidelberg (Germany); Stanke, Thomas [European Southern Observatory, Garching bei München (Germany); Billot, Nicolas [Instituto de Radio Astronomía Milimétrica, Granada (Spain); Tobin, John J. [Leiden Observatory, Leiden (Netherlands); Ali, Babar [Space Science Institute, Boulder, CO (United States); Allen, Lori E. [National Optical Astronomy Observatory, Tucson, AZ (United States); Watson, Dan M. [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States); Wilson, T. L., E-mail: wjfischer@gmail.com [Naval Research Laboratory, Washington, DC (United States)

    2015-02-10

    We report the dramatic mid-infrared brightening between 2004 and 2006 of Herschel Orion Protostar Survey (HOPS) 383, a deeply embedded protostar adjacent to NGC 1977 in Orion. By 2008, the source became a factor of 35 brighter at 24 μm with a brightness increase also apparent at 4.5 μm. The outburst is also detected in the submillimeter by comparing APEX/SABOCA to SCUBA data, and a scattered-light nebula appeared in NEWFIRM K{sub s} imaging. The post-outburst spectral energy distribution indicates a Class 0 source with a dense envelope and a luminosity between 6 and 14 L{sub ⊙}. Post-outburst time-series mid- and far-infrared photometry show no long-term fading and variability at the 18% level between 2009 and 2012. HOPS 383 is the first outbursting Class 0 object discovered, pointing to the importance of episodic accretion at early stages in the star formation process. Its dramatic rise and lack of fading over a 6 year period hint that it may be similar to FU Ori outbursts, although the luminosity appears to be significantly smaller than the canonical luminosities of such objects.

  6. Hubble 15 years of discovery

    CERN Document Server

    Lindberg Christensen, Lars; Kornmesser, M

    2006-01-01

    Hubble: 15 Years of Discovery was a key element of the European Space Agency's 15th anniversary celebration activities for the 1990 launch of the NASA/ESA Hubble Space Telescope. As an observatory in space, Hubble is one of the most successful scientific projects of all time, both in terms of scientific output and its immediate public appeal.

  7. Orion Project: Alternate Attitude Study

    Science.gov (United States)

    Alvarez-Hernandez, A.; Miller, Stephen W.

    2009-01-01

    This slide presentation reviews the study done on alternate attitudes for the Orion project's crew exploration vehicle. The analysis focused on the thermal performance of the vehicle with the alternate attitudes. The pressure vessel heater power, other vehicle heaters and radiator sink temperatures were included in the analysis.

  8. Cool gaseous nebulae

    CERN Document Server

    Shaver, P A; Pottasch, S R

    1979-01-01

    The electron temperatures of diffuse gaseous nebulae have long been thought to be close to 10/sup 4/K. Much lower temperatures were derived from some of the early radio continuum and recombination line work, but these were generally considered to be wrong for a variety of reasons. While there is little doubt that the bright nebulae do indeed have temperatures of approximately 8000-9000K, there are strong indications that some nebulae of lower densities have much lower temperatures, nebulae were made in order to determine electron temperatures in the absence of such effects as collisional de-excitation, stimulated emission, and pressure broadening. Several of these nebulae have been found to have temperatures below 5000K and for two of them which are discussed (RCW94 and G339.1-0.2) absolute upper limits of approximately 4700 K are imposed by the line widths alone. (11 refs).

  9. The variable Crab Nebula

    CERN Document Server

    Tavani, Marco

    2011-01-01

    The remarkable Crab Nebula is powered by an energetic pulsar whose relativistic wind interacts with the inner parts of the Supernova Remnant SN1054. Despite low-intensity optical and X-ray variations in the inner Nebula, the Crab has been considered until now substantially stable at X-ray and gamma-ray energies. This paradigm has been shattered by the AGILE discovery in September 2010 of a very intense transient gamma-ray flare of nebular origin. For the first time, the Crab Nebula was "caught in the act" of accelerating particles up to 10^15 eV within the shortest timescale ever observed in a cosmic nebula (1 day or less). Emission between 50 MeV and a few GeV was detected with a quite hard spectrum within a short timescale. Additional analysis and recent Crab Nebula data lead to identify a total of four major flaring gamma-ray episodes detected by AGILE and Fermi during the period mid-2007/mid-2011. These observations challenge emission models of the pulsar wind interaction and particle acceleration process...

  10. Clown Face Nebula (NGC 2392)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    A planetary nebula, also known as the Eskimo Nebula, in the constellation Gemini, position RA 07 h 29.2 m, dec. +20° 55'. It is bluish, 13'' in diameter, and of ninth magnitude, with a tenth-magnitude central star. The blue-green nebula's hazy outer regions are thought to resemble an Eskimo's hood or clown's ruff....

  11. HUBBLE PEEKS INTO A STELLAR NURSERY IN A NEARBY GALAXY

    Science.gov (United States)

    2002-01-01

    HUBBLE PEEKS INTO A STELLAR NURSERY IN A NEARBY GALAXY NASA's Hubble Space Telescope has peered deep into a neighboring galaxy to reveal details of the formation of new stars. Hubble's target was a newborn star cluster within the Small Magellanic Cloud, a small galaxy that is a satellite of our own Milky Way. The new images show young, brilliant stars cradled within a nebula, or glowing cloud of gas, cataloged as N 81. These massive, recently formed stars inside N 81 are losing material at a high rate, sending out strong stellar winds and shock waves and hollowing out a cocoon within the surrounding nebula. The two most luminous stars, seen in the Hubble image as a very close pair near the center of N 81, emit copious ultraviolet radiation, causing the nebula to glow through fluorescence. Outside the hot, glowing gas is cooler material consisting of hydrogen molecules and dust. Normally this material is invisible, but some of it can be seen in silhouette against the nebular background, as long dust lanes and a small, dark, elliptical-shaped knot. It is believed that the young stars have formed from this cold matter through gravitational contraction. Few features can be seen in N 81 from ground-based telescopes, earning it the informal nick-name 'The Blob.' Astronomers were not sure if just one or a few hot stars were embedded in the cloud, or if it was a stellar nursery containing a large number of less massive stars. Hubble's high-resolution imaging shows the latter to be the case, revealing that numerous young, white-hot stars---easily visible in the color picture---are contained within N 81. This crucial information bears strongly on theories of star formation, and N 81 offers a singular opportunity for a close-up look at the turbulent conditions accompanying the birth of massive stars. The brightest stars in the cluster have a luminosity equal to 300,000 stars like our own Sun. Astronomers are especially keen to study star formation in the Small Magellanic

  12. Automation Interfaces of the Orion GNC Executive Architecture

    Science.gov (United States)

    Hart, Jeremy

    2009-01-01

    This viewgraph presentation describes Orion mission's automation Guidance, Navigation and Control (GNC) architecture and interfaces. The contents include: 1) Orion Background; 2) Shuttle/Orion Automation Comparison; 3) Orion Mission Sequencing; 4) Orion Mission Sequencing Display Concept; and 5) Status and Forward Plans.

  13. Hierarchies of Models: Toward Understanding Planetary Nebulae

    Science.gov (United States)

    Knuth, Kevin H.; Hajian, Arsen R.; Clancy, Daniel (Technical Monitor)

    2003-01-01

    Stars like our sun (initial masses between 0.8 to 8 solar masses) end their lives as swollen red giants surrounded by cool extended atmospheres. The nuclear reactions in their cores create carbon, nitrogen and oxygen, which are transported by convection to the outer envelope of the stellar atmosphere. As the star finally collapses to become a white dwarf, this envelope is expelled from the star to form a planetary nebula (PN) rich in organic molecules. The physics, dynamics, and chemistry of these nebulae are poorly understood and have implications not only for our understanding of the stellar life cycle but also for organic astrochemistry and the creation of prebiotic molecules in interstellar space. We are working toward generating three-dimensional models of planetary nebulae (PNe), which include the size, orientation, shape, expansion rate and mass distribution of the nebula. Such a reconstruction of a PN is a challenging problem for several reasons. First, the data consist of images obtained over time from the Hubble Space Telescope (HST) and spectra obtained from Kitt Peak National Observatory (KPNO) and Cerro Tololo Inter-American Observatory (CTIO). These images are of course taken from a single viewpoint in space, which amounts to a very challenging tomographic reconstruction. Second, the fact that we have two disparate and orthogonal data types requires that we utilize a method that allows these data to be used together to obtain a solution. To address these first two challenges we employ Bayesian model estimation using a parameterized physical model that incorporates much prior information about the known physics of the PN. In our previous works we have found that the forward problem of the comprehensive model is extremely time consuming. To address this challenge, we explore the use of a set of hierarchical models, which allow us to estimate increasingly more detailed sets of model parameters. These hierarchical models of increasing complexity are akin

  14. Magnetically controlled solar nebula

    Science.gov (United States)

    Stepinski, T. F.; Reyes-Ruiz, M.

    1993-01-01

    It is widely believed that a primordial solar nebula, the precursor of the Sun and its planetary system, could be best described in terms of an accretion disk. Such an accretion disk is though to be turbulent, and it is usually imagined that turbulent viscosity alone provides the torque responsible for the structure and the evolution of the nebula. However, it was found that an MHD dynamo operating in a turbulent nebula can contemporaneously produce magnetic fields capable of significantly altering or even dominating the total torque. Thus, it seems that no model of a viscous solar nebula is complete without taking magnetic fields into consideration. It was demonstrated that there are usually two distinct regions of nebular disk where a dynamo can operate: the inner region, where the magnetic field coupled to gas due to relatively high thermal ionization; and the outer region, where this coupling is achieved due to nonthermal ionization. Most models also show the existence of an intermediate region, 'the magnetic gap,' where neither thermal nor nonthermal sources can produce enough ionization to provide the necessary coupling between the magnetic field and the gas. The location and width of the gap change substantially from one model to another. At present, we can only estimate the strength of a generated magnetic field. It seems that a large-scale magnetic field is likely to be in the equipartition with the turbulent kinetic energy; however, the intense magnetic fluctuations may greatly exceed this equipartition strength on short time and length scales. To show how a dynamo-generated magnetic field changes the structure of a viscous nebula, we consider four nebula models extensively.

  15. The Gould's Belt Distances Survey (GOBELINS) III. Distances and structure towards the Orion Molecular Clouds

    CERN Document Server

    Kounkel, Marina; Loinard, Laurent; Ortiz-León, Gisela N; Mioduszewski, Amy J; Rodríguez, Luis F; Dzib, Sergio A; Torres, Rosa M; Pech, Gerardo; Galli, Phillip A B; Rivera, Juana L; Boden, Andrew F; Evans, Neal J; Briceño, Cesar; Tobin, John J

    2016-01-01

    We present the results of the Gould's Belt Distances Survey (GOBELINS) of young star forming regions towards the Orion Molecular Cloud Complex. We detected 36 YSOs with the Very Large Baseline Array (VLBA), 27 of which have been observed in at least 3 epochs over the course of 2 years. At least half of these YSOs belong to multiple systems. We obtained parallax and proper motions towards these stars to study the structure and kinematics of the Complex. We measured a distance of 388$\\pm$5 pc towards the Orion Nebula Cluster, 428$\\pm$10 pc towards the southern portion L1641, 388$\\pm$10 pc towards NGC 2068, and roughly $\\sim$420 pc towards NGC 2024. Finally, we observed a strong degree of plasma radio scattering towards $\\lambda$ Ori.

  16. New Results on the Submillimeter Polarization Spectrum of the Orion Molecular Cloud

    CERN Document Server

    Vaillancourt, J E; Hildebrand, R H; Kirby, L; Krejny, M M; Li, H; Novak, G; Houde, M; Shinnaga, H; Attard, M

    2008-01-01

    We have used the SHARP polarimeter at the Caltech Submillimeter Observatory to map the polarization at wavelengths of 350 and 450 micron in a ~2 x 3 arcmin region of the Orion Molecular Cloud. The map covers the brightest region of the OMC-1 ridge including the Kleinmann-Low (KL) nebula and the submillimeter source Orion-south. The ratio of 450-to-350 micron polarization is ~ 1.3 +/- 0.3 in the outer parts of the cloud and drops by a factor of 2 towards KL. The outer cloud ratio is consistent with measurements in other clouds at similar wavelengths and confirms previous measurements placing the minimum of the polarization ratio in dusty molecular clouds at a wavelength ~ 350 micron.

  17. Astronomers celebrate a year of new Hubble results

    Science.gov (United States)

    1995-02-01

    according to current theories some of our Universe is missing! There just isn't enough visible matter in our Universe to account for known gravitational effects, such as the rotation of galaxies. As much as 90 percent of our Universe could be invisible to astronomers. The only other explanation is that our understanding of gravity is seriously wrong. "it's quite an embarrassing situation for scientists. We like to tell people that we know what we're doing but we can't find a good part of the mass in the Universe," said Dr Francesco Paresce, an ESA astronomer based at the STScI. "This is perhaps one of the most fundamental issues today in astronomy. The amount of matter determines almost everything about the Universe." The Hubble Space Telescope has joined the search for the so-called "dark or missing matter" anti so far it has eliminated one likely theory. Two groups of astronomers, one of which is led by Dr Paresce, have determined that the missing matter is not contained in dim stars called red dwarfs, which - before Hubble - were thought to be widespread. Astronomers expected to find a large number of these faint objects but instead they found, relatively speaking, only a handful. "This throws a big spanner into the whole subject, because all of a sudden you're saying that it can't be the simplest explanation that we all had. It's going to get a lot more complicated from now on," said Dr Paresce. Astronomers will now have to find another explanation for the missing mass. One possibility is that this elusive matter is not matter as we know it, but is actually mysterious exotic particles. Are we alone ? Hubble's work is also raising questions about the probability of life elsewhere in the Universe. Observations of young stars in the Orion Nebula have revealed that more than half are surrounded by discs of dust and gas, material that may be the building blocks of planets. Before, astronomers were aware of only a few stars with these so-called proto-planetary discs. The

  18. The Hubble Exoplanet Classroom

    Science.gov (United States)

    Stevens, Laura; Carson, J.; Ruwadi, D.; Low, K.; Jordan, S.; Schneider, G.

    2013-01-01

    We present a status report on the Hubble Exoplanet Classroom, an interactive website designed to engage 8-12th grade students in physical science concepts using the exciting field of exoplanet studies. Addressing national teaching standards, the webpage allows educators to enhance their physical science, physics, and astronomy curriculum with student-driven lessons. The webpage records students' performance on lessons and quizzes and compiles the results, which can be accessed by the instructor using a secure website.

  19. Dismantling Hubble's Legacy?

    CERN Document Server

    Way, Michael J

    2013-01-01

    Edwin Hubble is famous for a number of discoveries that are well known to amateur and professional astronomers, students and the general public. The origins of these discoveries are examined and it is demonstrated that, in each case, a great deal of supporting evidence was already in place. In some cases the discoveries had either already been made, or competing versions were not adopted for complex scientific and sociological reasons.

  20. Dismantling Hubble's Legacy?

    Science.gov (United States)

    Way, Michael Joseph

    2013-01-01

    Edwin Hubble is famous for a number of discoveries that are well known to amateur and professional astronomers, students and the general public. The origins of these discoveries are examined and it is demonstrated that, in each case, a great deal of supporting evidence was already in place. In some cases the discoveries had either already been made, or competing versions were not adopted for complex scientific and sociological reasons.

  1. The Hubble Constant.

    Science.gov (United States)

    Jackson, Neal

    2015-01-01

    I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H0 values of around 72-74 km s(-1) Mpc(-1), with typical errors of 2-3 km s(-1) Mpc(-1). This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67-68 km s(-1) Mpc(-1) and typical errors of 1-2 km s(-1) Mpc(-1). The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.

  2. ALMA Observations of Orion Source I at 350 and 660 GHz

    CERN Document Server

    Plambeck, R L

    2016-01-01

    Orion Source I ('SrcI') is the protostar at the center of the Kleinmann-Low Nebula. ALMA observations of SrcI at 350 and 660 GHz failed to detect the H26$\\alpha$ and H21$\\alpha$ recombination lines, ruling out the possibility that SrcI is a hypercompact HII region. The deconvolved size of the continuum source is approximately 0.23 x 0.05" (100 x 20 AU); it is interpreted as a disk viewed almost edge-on. The continuum flux density is proportional to $\

  3. Catalogues of planetary nebulae.

    Science.gov (United States)

    Acker, A.

    Firstly, the general requirements concerning catalogues are studied for planetary nebulae, in particular concerning the objects to be included in a catalogue of PN, their denominations, followed by reflexions about the afterlife and comuterized versions of a catalogue. Then, the basic elements constituting a catalogue of PN are analyzed, and the available data are looked at each time.

  4. Testing Orions Fairing Separation System

    Science.gov (United States)

    Martinez, Henry; Cloutier, Chris; Lemmon, Heber; Rakes, Daniel; Oldham, Joe; Schlagel, Keith

    2014-01-01

    Traditional fairing systems are designed to fully encapsulate and protect their payload from the harsh ascent environment including acoustic vibrations, aerodynamic forces and heating. The Orion fairing separation system performs this function and more by also sharing approximately half of the vehicle structural load during ascent. This load-share condition through launch and during jettison allows for a substantial increase in mass to orbit. A series of component-level development tests were completed to evaluate and characterize each component within Orion's unique fairing separation system. Two full-scale separation tests were performed to verify system-level functionality and provide verification data. This paper summarizes the fairing spring, Pyramidal Separation Mechanism and forward seal system component-level development tests, system-level separation tests, and lessons learned.

  5. The JCMT Legacy Survey of the Gould Belt: mapping 13CO and C18O in Orion A

    CERN Document Server

    Buckle, J V; Di Francesco, J; Graves, S F; Nutter, D; Richer, J S; Roberts, J F; Ward-Thompson, D; White, G J; Brunt, C; Butner, H M; Cavanagh, B; Chrysostomou, A; Curtis, E I; Duarte-Cabral, A; Etxaluze, M; Fich, M; Friberg, P; Friesen, R; Fuller, G A; Greaves, J S; Hatchell, J; Hogerheijde, M R; Johnstone, D; Matthews, B; Matthews, H; Rawlings, J M C; Sadavoy, S; Simpson, R J; Tothill, N F H; Tsamis, Y G; Viti, S; Wouterloot, J G A; Yates, J

    2012-01-01

    The Gould Belt Legacy Survey will map star-forming regions within 500 pc, using HARP (Heterodyne Array Receiver Programme), SCUBA-2 (Submillimetre Common-User Bolometer Array 2) and POL-2 (Polarimeter 2) on the James Clerk Maxwell Telescope (JCMT). This paper describes HARP observations of the J = 3-2 transitions of 13CO and C18O towards Orion A. The 1500-resolution observations cover 5 pc of the Orion filament, including OMC1 (inc. BN-KL and Orion Bar), OMC 2/3 and OMC 4, and allow a comparative study of the molecular gas properties throughout the star-forming cloud. The filament shows a velocity gradient of ~1 km/s /pc between OMC 1, 2 and 3, and high velocity emission is detected in both isotopologues. The Orion Nebula and Bar have the largest masses and line widths, and dominate the mass and energetics of the high velocity material. Compact, spatially resolved emission from CH3CN, 13CH3OH, SO, HCOOCH3, C2H5OH, CH3CHO and CH3OCHO is detected towards the Orion Hot Core. The cloud is warm, with a median exci...

  6. OBSERVATIONS OF THE CRAB NEBULA'S ASYMMETRICAL DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    Loll, A. M.; Desch, S. J.; Scowen, P. A. [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287 (United States); Foy, J. P., E-mail: allison.loll@asu.edu [Barrett, The Honors College, Arizona State University, P.O. Box 871612, Tempe, AZ 85287 (United States)

    2013-03-10

    We present the first Hubble Space Telescope Wide Field Planetary Camera-2 imaging survey of the entire Crab Nebula, in the filters F502N ([O III] emission), F673N ([S II]), F631N ([O I]), and F547M (continuum). We use our mosaics to characterize the pulsar wind nebula (PWN) and its three-dimensional structure, the ionizational structure in the filaments forming at its periphery, the speed of the shock driven by the PWN into surrounding ejecta (by inferring the cooling rates behind the shock), and the morphology and ionizational structure of the Rayleigh-Taylor (R-T) fingers. We quantify a number of asymmetries between the northwest (NW) and southeast (SE) quadrants of the Crab Nebula. The lack of observed filaments in the NW, and our observations of the spatial extent of [O III] emission lead us to conclude that cooling rates are slower, and therefore the shock speeds are greater, in the NW quadrant of the nebula, compared with the SE. We conclude that R-T fingers are longer, more ionizationally stratified, and apparently more massive in the NW than in the SE, and the R-T instability appears more fully developed in the NW.

  7. Observations of "wisps" in magnetohydrodynamic simulations of the Crab Nebula

    CERN Document Server

    Camus, N F; Buccantini, N; Hughes, P A

    2009-01-01

    In this letter, we describe results of new high-resolution axisymmetric relativistic MHD simulations of Pulsar Wind Nebulae. The simulations reveal strong breakdown of the equatorial symmetry and highly variable structure of the pulsar wind termination shock. The synthetic synchrotron maps, constructed using a new more accurate approach, show striking similarity with the well known images of the Crab Nebula obtained by Chandra, and the Hubble Space Telescope. In addition to the \\textit{jet-torus} structure, these maps reproduce the Crab's famous moving wisps whose speed and rateof production agree with the observations. The variability is then analyzed using various statistical methods, including the method of structure function and wavelet transform. The results point towards the quasi-periodic behaviour with the periods of 1.5-3yr and MHD turbulence on scales below 1yr. The full account of this study will be presented in a follow up paper.

  8. A wind-shell interaction model for multipolar planetary nebulae

    CERN Document Server

    Steffen, W; Esquivel, A; Garcia-Segura, G; Garcia-Diaz, Ma T; Lopez, J A; Magnor, M

    2013-01-01

    We explore the formation of multipolar structures in planetary and pre-planetary nebulae from the interaction of a fast post-AGB wind with a highly inhomogeneous and filamentary shell structure assumed to form during the final phase of the high density wind. The simulations were performed with a new hydrodynamics code integrated in the interactive framework of the astrophysical modeling package SHAPE. In contrast to conventional astrophysical hydrodynamics software, the new code does not require any programming intervention by the user for setting up or controlling the code. Visualization and analysis of the simulation data has been done in SHAPE without external software. The key conclusion from the simulations is that secondary lobes in planetary nebulae, such as Hubble 5 and K3-17, can be formed through the interaction of a fast low-density wind with a complex high density environment, such as a filamentary circumstellar shell. The more complicated alternative explanation of intermittent collimated outflow...

  9. Planetary nebulae as tracers of galaxy stellar populations

    CERN Document Server

    Buzzoni, A; Corradi, R L M

    2006-01-01

    We address the general problem of the luminosity-specific planetary nebula (PN) number, defined as alpha = N(PN)/L(gal), and its relationship with age and metallicity of the parent stellar population. Our analysis relies on population synthesis models for simple stellar populations and more elaborated galaxy models along the full star-formation range of the Hubble morphological sequence. This theoretical framework is compared with the updated census of the PN population in Local Group galaxies and external ellipticals in the Leo group, and the Virgo and Fornax clusters.

  10. The Hubble Constant

    Directory of Open Access Journals (Sweden)

    Neal Jackson

    2015-09-01

    Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H_0 values of around 72–74 km s^–1 Mpc^–1, with typical errors of 2–3 km s^–1 Mpc^–1. This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67–68 km s^–1 Mpc^–1 and typical errors of 1–2 km s^–1 Mpc^–1. The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.

  11. The large scale view of the young stellar populations in the Orion OB1 Association

    Science.gov (United States)

    Briceno, Cesar; Calvet, Nuria

    2016-06-01

    The Orion OB1 association, at ~400 pc and with a wide range of ages (~1-10 Myr) and environmental conditions, is an ideal place to look at how stars form, first evolve and disperse among the general population of field stars. Also to study disk dispersal and the duration of the planet formation phase.However, despite spanning nearly 200 deg2 on the sky, almost all we know about Orion comes from studies of a limited fraction of the entire region, mostly of the youngest objects (~B molecular clouds and the ~3 Myr old sigma Ori cluster.We will present here the results of our 180 sq deg photometric multi-epoch survey across the Orion OB1 association, using the known variability of T Tauri stars to pick them among the general field population, and following with spectroscopy to confirm members and characterize them.The ~2000 newly identified young low-mass stars are mostly located away from the molecular clouds, across tens of sq. deg. in the Orion OB1a and OB1b sub-associations, with ages in the range ~4-10 Myr. But within this general population we identify a significant fraction concentrated in distinct overdensities, most notably the ~7 Myr old 25 Orionis cluster. These stellar aggregates point to a previously unknown degree of substructure that has survived the dissipation of the parent molecular clouds. We also find that the Orion Nebula Cluster is surrounded by a few sq.deg. halo of young stars, as has been suggested by recent sudies.

  12. New portrait of Omega Nebula's glistening watercolours

    Science.gov (United States)

    2009-07-01

    newly released image, obtained with the EMMI instrument attached to the ESO 3.58-metre New Technology Telescope (NTT) at La Silla, Chile, shows the central region of the Omega Nebula in exquisite detail. In 2000, another instrument on the NTT, called SOFI, captured another striking image of the nebula (ESO Press Photo 24a/00) in the near-infrared, giving astronomers a penetrating view through the obscuring dust, and clearly showing many previously hidden stars. The NASA/ESA Hubble Space Telescope has also imaged small parts of this nebula (heic0305a and heic0206d) in fine detail. At the left of the image a huge and strangely box-shaped cloud of dust covers the glowing gas. The fascinating palette of subtle colour shades across the image comes from the presence of different gases (mostly hydrogen, but also oxygen, nitrogen and sulphur) that are glowing under the fierce ultraviolet light radiated by the hot young stars. More Information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning a 42-metre European Extremely Large

  13. VizieR Online Data Catalog: Hubble Tarantula Treasury Project (HTTP). III. (Sabbi+, 2016)

    Science.gov (United States)

    Sabbi, E.; Lennon, D. J.; Anderson, J.; Cignoni, M.; van der Marel, R. P.; Zaritsky, D.; de Marchi, G.; Panagia, N.; Gouliermis, D. A.; Grebel, E. K.; Gallagher, J. S., III; Smith, L. J.; Sana, H.; Aloisi, A.; Tosi, M.; Evans, C. J.; Arab, H.; Boyer, M.; de Mink, S. E.; Gordon, K.; Koekemoer, A. M.; Larsen, S. S.; Ryon, J. E.; Zeidler, P.

    2016-02-01

    Hubble Tarantula Treasury Project (HTTP; HST 12939, PI Elena Sabbi + HST 12499, PI Danny Lennon) was awarded 60 orbits of HST time in cycle 20 to survey the entire Tarantula Nebula (30 Doradus), using both the UVIS and the IR channels of the Wide Field Camera 3 (WFC3), and, in parallel, the Wide Field Channel (WFC) of the Advanced Camera for Surveys (ACS). See log of the observations (from 2011 Oct 03 to 2013 Sep 17) in table 1. (2 data files).

  14. The Carnegie Hubble Program

    Science.gov (United States)

    Freedman, Wendy L.; Madore, Barry F.; Scowcroft, Vicky; Mnso, Andy; Persson, S. E.; Rigby, Jane; Sturch, Laura; Stetson, Peter

    2011-01-01

    We present an overview of and preliminary results from an ongoing comprehensive program that has a goal of determining the Hubble constant to a systematic accuracy of 2%. As part of this program, we are currently obtaining 3.6 micron data using the Infrared Array Camera (IRAC) on Spitzer, and the program is designed to include JWST in the future. We demonstrate that the mid-infrared period-luminosity relation for Cepheids at 3.6 microns is the most accurate means of measuring Cepheid distances to date. At 3.6 microns, it is possible to minimize the known remaining systematic uncertainties in the Cepheid extragalactic distance scale. We discuss the advantages of 3.6 micron observations in minimizing systematic effects in the Cepheid calibration of the Hubble constant including the absolute zero point, extinction corrections, and the effects of metallicity on the colors and magnitudes of Cepheids. We are undertaking three independent tests of the sensitivity of the mid-IR Cepheid Leavitt Law to metallicity, which when combined will allow a robust constraint on the effect. Finally, we are providing a new mid-IR Tully-Fisher relation for spiral galaxies.

  15. Hubble Space Telescope satellite

    Science.gov (United States)

    Mitchell, R. E.

    1985-01-01

    The Hubble Space Telescope, named for the American astronomer Edwin Powell Hubble, will be the largest and most powerful astronomical instrument ever orbited. Placed above the obscuring effects of the earth's atmosphere in a 600-km orbit, this remotely-controlled, free-flying satellite observatory will expand the terrestrial-equivalent resolution of the universe by a factor of seven, or a volumetric factor of 350. This telescope has a 2.4-m primary mirror and can accommodate five scientific instruments (cameras, spectrographs and photometers). The optics are suitable for a spectral range from 1100 angstrom to 1 mm wavelength. With a projected service life of fifteen years, the spacecraft can be serviced on-orbit for replacement of degraded systems, to insert advanced scientific instruments, and to reboost the telescope from decayed altitudes. The anticipated image quality will be a result of extremely precise lambda/20 optics, stringent cleanliness, and very stable pointing: jitter will be held to less than 0.01 arcsecond for indefinite observation periods, consistent with instrument apertures as small as 0.1 arcsecond.

  16. The Carnegie Hubble Program

    CERN Document Server

    Freedman, Wendy L; Scowcroft, Vicky; Monson, Andy; Persson, S E; Seibert, Mark; Rigby, Jane; Sturch, Laura; Stetson, Peter

    2011-01-01

    We present an overview of and preliminary results from an ongoing comprehensive program that has a goal of determining the Hubble constant to a systematic accuracy of 2%. As part of this program, we are currently obtaining 3.6 micron data using the Infrared Array Camera (IRAC) on Spitzer, and the program is designed to include JWST in the future. We demonstrate that the mid-infrared period-luminosity relation for Cepheids at 3.6 microns is the most accurate means of measuring Cepheid distances to date. At 3.6 microns, it is possible to minimize the known remaining systematic uncertainties in the Cepheid extragalactic distance scale. We discuss the advantages of 3.6 micron observations in minimizing systematic effects in the Cepheid calibration of the Hubble constant including the absolute zero point, extinction corrections, and the effects of metallicity on the colors and magnitudes of Cepheids. We are undertaking three independent tests of the sensitivity of the mid-IR Cepheid Leavitt Law to metallicity, whi...

  17. Hubble Tarantula Treasury Project - IV. The extinction law

    Science.gov (United States)

    De Marchi, Guido; Panagia, Nino; Sabbi, Elena; Lennon, Daniel; Anderson, Jay; van der Marel, Roeland; Cignoni, Michele; Grebel, Eva K.; Larsen, Søren; Zaritsky, Dennis; Zeidler, Peter; Gouliermis, Dimitrios; Aloisi, Alessandra

    2016-02-01

    We report on the study of interstellar extinction across the Tarantula Nebula (30 Doradus), in the Large Magellanic Cloud, using observations from the Hubble Tarantula Treasury Project in the 0.3-1.6 μm range. The considerable and patchy extinction inside the nebula causes about 3500 red clump stars to be scattered along the reddening vector in the colour-magnitude diagrams, thereby allowing an accurate determination of the reddening slope in all bands. The measured slope of the reddening vector is remarkably steeper in all bands than in the the Galactic diffuse interstellar medium. At optical wavelengths, the larger ratio of total-to-selective extinction, namely RV = 4.5 ± 0.2, implies the presence of a grey component in the extinction law, due to a larger fraction of large grains. The extra large grains are most likely ices from supernova ejecta and will significantly alter the extinction properties of the region until they sublimate in 50-100 Myr. We discuss the implications of this extinction law for the Tarantula Nebula and in general for regions of massive star formation in galaxies. Our results suggest that fluxes of strongly star-forming regions are likely to be underestimated by a factor of about 2 in the optical.

  18. Orion in a New Light - VISTA exposes high-speed antics of young stars

    Science.gov (United States)

    2010-02-01

    The Orion Nebula reveals many of its hidden secrets in a dramatic image taken by ESO's new VISTA survey telescope. The telescope's huge field of view can show the full splendour of the whole nebula and VISTA's infrared vision also allows it to peer deeply into dusty regions that are normally hidden and expose the curious behaviour of the very active young stars buried there. VISTA - the Visible and Infrared Survey Telescope for Astronomy - is the latest addition to ESO's Paranal Observatory (eso0949). It is the largest survey telescope in the world and is dedicated to mapping the sky at infrared wavelengths. The large (4.1-metre) mirror, wide field of view and very sensitive detectors make VISTA a unique instrument. This dramatic new image of the Orion Nebula illustrates VISTA's remarkable powers. The Orion Nebula [1] is a vast stellar nursery lying about 1350 light-years from Earth. Although the nebula is spectacular when seen through an ordinary telescope, what can be seen using visible light is only a small part of a cloud of gas in which stars are forming. Most of the action is deeply embedded in dust clouds and to see what is really happening astronomers need to use telescopes with detectors sensitive to the longer wavelength radiation that can penetrate the dust. VISTA has imaged the Orion Nebula at wavelengths about twice as long as can be detected by the human eye. As in the many visible light pictures of this object, the new wide field VISTA image shows the familiar bat-like form of the nebula in the centre of the picture as well as the fascinating surrounding area. At the very heart of this region lie the four bright stars forming the Trapezium, a group of very hot young stars pumping out fierce ultraviolet radiation that is clearing the surrounding region and making the gas glow. However, observing in the infrared allows VISTA to reveal many other young stars in this central region that cannot be seen in visible light. Looking to the region above the

  19. Cosmology: From Hubble to HST

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Michael S.

    1997-03-01

    The Hubble constant sets the size and age of the Universe, and, together with independent determinations of the age, provides a consistency check of the standard cosmology. The Hubble constant also provides an important test of our most attractive paradigm for extending the standard cosmology, inflation and cold dark matter.

  20. The Cosmic Bat - An Island of Stars in the Making on the Outskirts of Orion

    Science.gov (United States)

    2010-03-01

    The delicate nebula NGC 1788, located in a dark and often neglected corner of the Orion constellation, is revealed in a new and finely nuanced image that ESO is releasing today. Although this ghostly cloud is rather isolated from Orion's bright stars, the latter's powerful winds and light have had a strong impact on the nebula, forging its shape and making it home to a multitude of infant suns. Stargazers all over the world are familiar with the distinctive profile of the constellation of Orion (the Hunter). Fewer know about the nebula NGC 1788, a subtle, hidden treasure just a few degrees away from the bright stars in Orion's belt. NGC 1788 is a reflection nebula, whose gas and dust scatter the light coming from a small cluster of young stars in such a way that the tenuous glow forms a shape reminiscent of a gigantic bat spreading its wings. Very few of the stars belonging to the nebula are visible in this image, as most of them are obscured by the dusty cocoons surrounding them. The most prominent, named HD 293815, can be distinguished as the bright star in the upper part of the cloud, just above the centre of the image and the pronounced dark lane of dust extending through the nebula. Although NGC 1788 appears at first glance to be an isolated cloud, observations covering a field beyond the one presented in this image have revealed that bright, massive stars, belonging to the vast stellar groupings in Orion, have played a decisive role in shaping NGC 1788 and stimulating the formation of its stars. They are also responsible for setting the hydrogen gas ablaze in the parts of the nebula facing Orion, leading to the red, almost vertical rim visible in the left half of the image. All the stars in this region are extremely young, with an average age of only a million years, a blink of an eye compared to the Sun's age of 4.5 billion years. Analysing them in detail, astronomers have discovered that these "preschool" stars fall naturally into three well separated

  1. Physical Structure of Planetary Nebulae. I. The Owl Nebula

    CERN Document Server

    Guerrero, M A; Manchado, A; Kwitter, K B

    2003-01-01

    The Owl Nebula is a triple-shell planetary nebula with the outermost shell being a faint bow-shaped halo. We have obtained deep narrow-band images and high-dispersion echelle spectra in the H-alpha, [O III], and [N II] emission lines to determine the physical structure of each shell in the nebula. These spatio-kinematic data allow us to rule out hydrodynamic models that can reproduce only the nebular morphology. Our analysis shows that the inner shell of the main nebula is slightly elongated with a bipolar cavity along its major axis, the outer nebula is a filled envelope co-expanding with the inner shell at 40 km/s, and the halo has been braked by the interstellar medium as the Owl Nebula moves through it. To explain the morphology and kinematics of the Owl Nebula, we suggest the following scenario for its formation and evolution. The early mass loss at the TP-AGB phase forms the halo, and the superwind at the end of the AGB phase forms the main nebula. The subsequent fast stellar wind compressed the superwi...

  2. The Hubble Constant

    Directory of Open Access Journals (Sweden)

    Jackson Neal

    2007-09-01

    Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. In the last 20 years, much progress has been made and estimates now range between 60 and 75 km s^-1 Mpc^-1, with most now between 70 and 75 km s^-1 Mpc^-1, a huge improvement over the factor-of-2 uncertainty which used to prevail. Further improvements which gave a generally agreed margin of error of a few percent rather than the current 10% would be vital input to much other interesting cosmology. There are several programmes which are likely to lead us to this point in the next 10 years.

  3. Modelling the 3D morphology and proper motions of the planetary nebula NGC 6302

    CERN Document Server

    Uscanga, L; Esquivel, A; Raga, A C; Boumis, P; Cantó, J

    2014-01-01

    We present 3D hydrodynamical simulations of an isotropic fast wind interacting with a previously ejected toroidally-shaped slow wind in order to model both the observed morphology and the kinematics of the planetary nebula (PN) NGC 6302. This source, also known as the Butterfly nebula, presents one of the most complex morphologies ever observed in PNe. From our numerical simulations, we have obtained an intensity map for the H$\\alpha$ emission to make a comparison with the Hubble Space Telescope (HST) observations of this object. We have also carried out a proper motion (PM) study from our numerical results, in order to compare with previous observational studies. We have found that the two interacting stellar wind model reproduces well the morphology of NGC 6302, and while the PM in the models are similar to the observations, our results suggest that an acceleration mechanism is needed to explain the Hubble-type expansion found in HST observations.

  4. Search for HOOH in Orion

    CERN Document Server

    Liseau, René

    2015-01-01

    Context: The abundance of key molecules determines the level of cooling that is necessary for the formation of stars and planetary systems. In this context, one needs to understand the details of the time dependent oxygen chemistry, leading to the formation of molecular oxygen and water. Aims: We aim to determine the degree of correlation between the occurrence of O2 and HOOH (hydrogen peroxide) in star-forming molecular clouds. We first detected O2 and HOOH in the rho Ophiuchi cloud (core A), we now search for HOOH in Orion Molecular Cloud OMC A, where O2 has also been detected. Methods: We mapped a 3 arcmin times 3 arcmin region around Orion H2-Peak 1 with the Atacama Pathfinder Experiment (APEX). In addition to several maps in two transitions of HOOH, viz. 219.17 GHz and 251.91 GHz, we obtained single-point spectra for another three transitions towards the position of maximum emission. Results: Line emission at the appropriate LSR-velocity (Local Standard of Rest) and at the level of greater or equal to 4 ...

  5. Laboratory Characterization and Astrophysical Detection of Vibrationally Excited States of Vinyl Cyanide in Orion-KL

    CERN Document Server

    López, A; Kisiel, Z; Daly, A M; Bermúdez, C; Calcutt, H; Marcelino, N; Viti, S; Drouin, B J; Medvedev, I R; Neese, C F; Pszczółkowski, L; Alonso, J L; Cernicharo, J

    2014-01-01

    New laboratory data of CH$_2$CHCN (vinyl cyanide) in its ground and vibrationally excited states at the microwave to THz domain allow searching for these excited state transitions in the Orion-KL line survey. Frequency-modulated spectrometers combined into a single broadband 50-1900 GHz spectrum provided measurements of CH$_2$CHCN covering a spectral range of 18-1893 GHz, whose assignments was confirmed by Stark modulation spectra in the 18-40 GHz region and by ab-initio anharmonic force field calculations. For analyzing the emission lines of CH$_2$CHCN species detected in Orion-KL we used the excitation and radiative transfer code (MADEX) at LTE conditions. The rotational transitions of the ground state of this molecule emerge from four cloud components of hot core nature which trace the physical and chemical conditions of high mass star forming regions in the Orion-KL Nebula. The total column density of CH$_2$CHCN in the ground state is (3.0$\\pm$0.9)x10$^{15}$ cm$^{-2}$. We report on the first interstellar ...

  6. Spectroscopy of Intermediate Mass Members of the Orion OB1a and b associations

    Science.gov (United States)

    Walter, Frederick M.; Sherry, William; Kim, Serena; Brittain, Sean

    2010-08-01

    OB associations are ideal sites for probing the formation of low mass stars. There has been little systematic study of the low mass stars in the largest nearby OB association, Orion OB1, aside from the Orion Nebula and σ Ori clusters. In an attempt to map the mass function and its spatial variation from 40 to below 0.01 M_⊙, we have completed a near-IR (JHK) survey of about 18 square degrees in the Orion OB1a and OB1b associations using the CPAPIR camera on the SMARTS/CTIO 1.5m telescope, supplemented by a VRI survey using the Steward Observatory Bok/90Prime and the KPNO 4m/MOSAIC cameras, as well as deep 4m/NEWFIRM images. The photometry reveals thousands of candidate association members. We request time with HYDRA to obtain spectra of the brighter candidate members (V<19), in order to confirm youth and membership from Li abundances, chromospheric activity, and radial velocities.

  7. Chemical abundances in Orion protoplanetary discs: integral field spectroscopy and photoevaporation models of HST 10

    CERN Document Server

    Tsamis, Y G; Henney, W J; Walsh, J R; Mesa-Delgado, A

    2012-01-01

    Photoevaporating protoplanetary discs (proplyds) in the vicinity of hot massive stars, such as those found in Orion, are important objects of study for the fields of star formation, early disc evolution, planetary formation, and H II region astrophysics. Their element abundances are largely unknown, unlike those of the main-sequence stars or the host Orion nebula. We present a spectroscopic analysis of the Orion proplyd HST 10, based on integral field observations with the Very Large Telescope/FLAMES fibre array at a resolution of 0.31" x 0.31". The proplyd and its vicinity are imaged in a variety of emission lines across a 6.6" x 4.2" area. The reddening, electron density and temperature are mapped out from various line diagnostics. The abundances of helium, and eight heavy elements are measured relative to hydrogen using the direct method based on the [O III] electron temperature. The abundance ratios of O/H and S/H are derived without resort to ionization correction factors. We construct dynamic photoevapo...

  8. HST observations of the nebula around the central compact object in the Vela Jr. supernova remnant

    Science.gov (United States)

    Mignani, R. P.; de Luca, A.; Pellizzoni, A.

    2009-12-01

    Context: A handful of young (a few thousand years) supernova remnants (SNRs) host point-like X-ray sources, dubbed central compact objects (CCOs), which are thought to be radio-silent isolated neutron stars formed by the supernova explosion. So far, no CCO has been firmly detected at other wavelengths. However, ground-based observation in the Hα band detected a nebula around CXO J085201.4-461753, the CCO in the Vela Jr. SNR. The nebula has also been detected in deep R-band observations performed with the Very Large Telescope (VLT). Interestingly, both its extension and its flux in the R band are consistent with those measured in Hα, suggesting that the nebula spectrum is dominated by line emission, possibly produced by a velocity-driven bow-shock in the interstellar medium (ISM) or by its photo-ionisation from the neutron star. Aims: The aim of this work is to resolve the morphology of the Hα nebula around the CCO to verify the proposed interpretations. Methods: We performed high-resolution imaging observations of the nebula with the Wide Field Planetary Camera 2 (WFPC2) of the Hubble Space Telescope (HST) through the 656N filter, almost exactly centred on the rest wavelength of the Hα line. Results: Surprisingly enough, we did not detect the nebula in our WFPC2 image down to a 3 σ flux limit of ~3 × 10-15 erg cm-2 s-1. This limit is a factor of 10 fainter than the nebula flux measured in the discovery ground-based observations which were, however, performed with redder and broader Hα filters. Conclusions: The non-detection of the nebula in the narrower and bluer WFPC2 656N filter suggests that the peak of the emission might actually be at longer wavelengths. One possibility, compatible with the bow-shock scenario only, is that the Hα line is red-shifted by ~10-60 Å due to the neutron star motion with a radial velocity 450 ⪉ Vr ⪉ 2700 km s-1. The other possibility is that the nebula is a knot of [NII] emission (λ = 6583.6 Å) unrelated to CXO J085201

  9. The complexity of Orion: an ALMA view. II. gGg'-ethylene glycol and acetic acid

    Science.gov (United States)

    Favre, C.; Pagani, L.; Goldsmith, P. F.; Bergin, E. A.; Carvajal, M.; Kleiner, I.; Melnick, G.; Snell, R.

    2017-07-01

    We report the first detection and high angular resolution (1.8″× 1.1″) imaging of acetic acid (CH3COOH) and gGg'-ethylene glycol (gGg'(CH2OH)2) toward the Orion Kleinmann-Low (Orion-KL) nebula. The observations were carried out at 1.3 mm with ALMA during Cycle 2. A notable result is that the spatial distribution of the acetic acid and ethylene glycol emission differs from that of the other O-bearing molecules within Orion-KL. While the typical emission of O-bearing species harbors a morphology associated with a V-shape linking the hot core region to the compact ridge (with an extension toward the BN object), the emission of acetic acid and ethylene glycol mainly peaks at about 2'' southwest from the hot core region (near sources I and n). We find that the measured CH3COOH:aGg'(CH2OH)2 and CH3COOH:gGg'(CH2OH)2 ratios differ from those measured toward the low-mass protostar IRAS 16293-2422 by more than one order of magnitude. Our best hypothesis to explain these findings is that CH3COOH, aGg'(CH2OH)2, and gGg'(CH2OH)2 are formed on the icy surface of grains and are then released into the gas-phase via co-desorption with water, by way of a bullet of matter ejected during the explosive event that occurred in the heart of the nebula about 500-700 yr ago.

  10. HUBBLE VISION: A Planetarium Show About Hubble Space Telescope

    Science.gov (United States)

    Petersen, Carolyn Collins

    1995-05-01

    In 1991, a planetarium show called "Hubble: Report From Orbit" outlining the current achievements of the Hubble Space Telescope was produced by the independent planetarium production company Loch Ness Productions, for distribution to facilities around the world. The program was subsequently converted to video. In 1994, that program was updated and re-produced under the name "Hubble Vision" and offered to the planetarium community. It is periodically updated and remains a sought-after and valuable resource within the community. This paper describes the production of the program, and the role of the astronomical community in the show's production (and subsequent updates). The paper is accompanied by a video presentation of Hubble Vision.

  11. Preplanetary Nebulae: An HST Imaging Survey and a New Morphological Classification System

    CERN Document Server

    Sahai, Raghvendra; Contreras, Carmen Sánchez; Claussen, Mark

    2007-01-01

    Using the Hubble Space Telescope (HST), we have carried out a survey of candidate preplanetary nebulae (PPNs). We report here our discoveries of objects having well-resolved geometrical structures, and use the large sample of PPNs now imaged with HST (including previously studied objects in this class) to devise a comprehensive morphological classification system for this category of objects. The wide variety of aspherical morphologies which we have found for PPNs are qualitatively similar to those found for young planetary nebulae in previous surveys. We also find prominent halos surrounding the central aspherical shapes in many of our objects -- these are direct signatures of the undisturbed circumstellar envelopes of the progenitor AGB stars. Although the majority of these have surface-brightness distributions consistent with a constant mass-loss rate with a constant expansion velocity, there are also examples of objects with varying mass-loss rates. As in our surveys of young planetary nebulae (PNs), we f...

  12. Peering into the Heart of the Crab Nebula

    Science.gov (United States)

    2000-01-01

    In the year 1054 A.D., Chinese astronomers were startled by the appearance of a new star, so bright that it was visible in broad daylight for several weeks. Today, the Crab Nebula is visible at the site of the 'Guest Star.' Located about 6,500 light-years from Earth, the Crab Nebula is the remnant of a star that began its life with about 10 times the mass of our own Sun. Its life ended on July 4, 1054 when it exploded as a supernova. In this image, NASA's Hubble Space Telescope has zoomed in on the center of the Crab to reveal its structure with unprecedented detail. The Crab Nebula data were obtained by Hubble's Wide Field and Planetary Camera 2 in 1995. Images taken with five different color filters have been combined to construct this new false-color picture. Resembling an abstract painting by Jackson Pollack, the image shows ragged shards of gas that are expanding away from the explosion site at over 3 million miles per hour. The core of the star has survived the explosion as a pulsar, visible in the Hubble image as the lower of the two moderately bright stars to the upper left of center. The pulsar is a neutron star that spins on its axis 30 times a second. It heats its surroundings, creating the ghostly diffuse bluish-green glowing gas cloud in its vicinity, including a blue arc just to its right. The colorful network of filaments is the material from the outer layers of the star that was expelled during the explosion. The picture is somewhat deceptive in that the filaments appear to be close to the pulsar. In reality, the yellowish green filaments toward the bottom of the image are closer to us, and approaching at some 300 miles per second. The orange and pink filaments toward the top of the picture include material behind the pulsar, rushing away from us at similar speeds. The various colors in the picture arise from different chemical elements in the expanding gas, including hydrogen (orange), nitrogen (red), sulfur (pink), and oxygen (green). The shades

  13. Search for HOOH in Orion

    Science.gov (United States)

    Liseau, R.; Larsson, B.

    2015-11-01

    Context. The abundance of key molecules determines the level of cooling that is necessary for the formation of stars and planetary systems. In this context, one needs to understand the details of the time dependent oxygen chemistry, leading to the formation of O2 and H2O. Aims: We aim to determine the degree of correlation between the occurrence of O2 and HOOH (hydrogen peroxide) in star-forming molecular clouds. We first detected O2 and HOOH in ρ Oph A, we now search for HOOH in Orion OMC A, where O2 has also been detected. Methods: We mapped a 3'×3' region around Orion H2-Peak 1 with the Atacama Pathfinder Experiment (APEX). In addition to several maps in two transitions of HOOH, viz. 219.17 GHz and 251.91 GHz, we obtained single-point spectra for another three transitions towards the position of maximum emission. Results: Line emission at the appropriate LSR-velocity (Local Standard of Rest) and at the level of ≥4σ was found for two transitions, with lower signal-to-noise ratio (2.8-3.5σ) for another two transitions, whereas for the remaining transition, only an upper limit was obtained. The emitting region, offset 18'' south of H2-Peak 1, appeared point-like in our observations with APEX. Conclusions: The extremely high spectral line density in Orion makes the identification of HOOH much more difficult than in ρ Oph A. As a result of having to consider the possible contamination by other molecules, we left the current detection status undecided. Based on observations with APEX, which is a 12 m diameter submillimetre telescope at 5100 m altitude on Llano Chajnantor in Chile. The telescope is operated by Onsala Space Observatory, Max-Planck-Institut für Radioastronomie (MPIfR), and European Southern Observatory (ESO).The final reduced data cube (FITS files) is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/583/A53

  14. Chandra X-Ray Observatory Image of Crab Nebula

    Science.gov (United States)

    1999-01-01

    After barely 2 months in space, the Chandra X-Ray Observatory (CXO) took this sturning image of the Crab Nebula, the spectacular remains of a stellar explosion, revealing something never seen before, a brilliant ring around the nebula's heart. The image shows the central pulsar surrounded by tilted rings of high-energy particles that appear to have been flung outward over a distance of more than a light-year from the pulsar. Perpendicular to the rings, jet-like structures produced by high-energy particles blast away from the pulsar. Hubble Space Telescope images have shown moving knots and wisps around the neutron star, and previous x-ray images have shown the outer parts of the jet and hinted at the ring structure. With CXO's exceptional resolution, the jet can be traced all the way in to the neutron star, and the ring pattern clearly appears. The image was made with CXO's Advanced Charge-Coupled Device (CCD) Imaging Spectrometer (ACIS) and High Energy Transmission Grating. The Crab Nebula, easily the most intensively studied object beyond our solar system, has been observed using virtually every astronomical instrument that could see that part of the sky

  15. Orion

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    (the Hunter; abbrev. Ori, gen. Orionis; area 594 sq. deg.) An equatorial constellation which lies between Taurus and Monoceros, and culminates at midnight in mid-December. Its origin dates back to Sumerian times, when it was identified with the hero Gilgamesh and his fight against the Bull of Heaven (represented by Taurus), but today it is associated with the son of Poseidon, in Greek mythology, ...

  16. ALMA OBSERVATIONS OF THE COLDEST PLACE IN THE UNIVERSE: THE BOOMERANG NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, R. [Jet Propulsion Laboratory, MS 183-900, California Institute of Technology, Pasadena, CA 91109 (United States); Vlemmings, W. H. T. [Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, SE-43992 Onsala (Sweden); Huggins, P. J. [Physics Department, New York University, 4 Washington Place, New York, NY 10003 (United States); Nyman, L.-Å. [Joint ALMA Observatory (JAO), Alonso de Cordova 3107, Vitacura, Santiago de Chile (Chile); Gonidakis, I., E-mail: raghvendra.sahai@jpl.nasa.gov [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Marsfield NSW 2122 (Australia)

    2013-11-10

    The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.

  17. ALMA Observations of the Coldest Place in the Universe: The Boomerang Nebula

    Science.gov (United States)

    Sahai, R.; Vlemmings, W. H. T.; Huggins, P. J.; Nyman, L.-Å.; Gonidakis, I.

    2013-11-01

    The Boomerang Nebula is the coldest known object in the universe, and an extreme member of the class of pre-planetary nebulae, objects which represent a short-lived transitional phase between the asymptotic giant branch and planetary nebula evolutionary stages. Previous single-dish CO (J = 1-0) observations (with a 45'' beam) showed that the high-speed outflow in this object has cooled to a temperature significantly below the temperature of the cosmic background radiation. Here we report the first observations of the Boomerang Nebula with ALMA in the CO J = 2-1 and J = 1-0 lines to resolve the structure of this ultra-cold nebula. We find a central hourglass-shaped nebula surrounded by a patchy, but roughly round, cold high-velocity outflow. We compare the ALMA data with visible-light images obtained with the Hubble Space Telescope and confirm that the limb-brightened bipolar lobes seen in these data represent hollow cavities with dense walls of molecular gas and dust producing both the molecular-emission-line and scattered-light structures seen at millimeter and visible wavelengths. The large diffuse biconical shape of the nebula seen in the visible wavelength range is likely due to preferential illumination of the cold, high-velocity outflow. We find a compact source of millimeter-wave continuum in the nebular waist—these data, together with sensitive upper limits on the radio continuum using observations with ATCA, indicate the presence of a substantial mass of very large (millimeter-sized) grains in the waist of the nebula. Another unanticipated result is the detection of CO emission regions beyond the ultra-cold region which indicate the re-warming of the cold gas, most likely due to photoelectric grain heating.

  18. The Gould’s Belt Distances Survey (GOBELINS) II. Distances and Structure toward the Orion Molecular Clouds

    Science.gov (United States)

    Kounkel, Marina; Hartmann, Lee; Loinard, Laurent; Ortiz-León, Gisela N.; Mioduszewski, Amy J.; Rodríguez, Luis F.; Dzib, Sergio A.; Torres, Rosa M.; Pech, Gerardo; Galli, Phillip A. B.; Rivera, Juana L.; Boden, Andrew F.; Evans, Neal J., II; Briceño, Cesar; Tobin, John J.

    2017-01-01

    We present the results of the Gould’s Belt Distances Survey of young star-forming regions toward the Orion Molecular Cloud Complex. We detected 36 young stellar objects (YSOs) with the Very Large Baseline Array, 27 of which have been observed in at least three epochs over the course of two years. At least half of these YSOs belong to multiple systems. We obtained parallax and proper motions toward these stars to study the structure and kinematics of the Complex. We measured a distance of 388 ± 5 pc toward the Orion Nebula Cluster, 428 ± 10 pc toward the southern portion L1641, 388 ± 10 pc toward NGC 2068, and roughly ∼420 pc toward NGC 2024. Finally, we observed a strong degree of plasma radio scattering toward λ Ori.

  19. Forming Planets in the Hostile Carina Nebula

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    Hubble images of the globules; the bottom panels are ALMA images of the disks detected within them. [Mesa-Delgado et al. 2016]In searching regions outside of the densest, most luminous clusters, the team succeeded in detecting two protoplanetary disks. This region in Carina now marks the most distant massive cluster in which disks have ever been imaged! The discovered disks have radii of roughly 60 AU and masses of 30 and 50 Jupiter masses and given their ages, its entirely plausible that planets are actively forming in these disks.Equally important: Mesa-Delgado and collaborators failed to detect any indication of disks in the core of Trumpler 14, a cluster in Carina that is home to some of the most massive and luminous stars in the Galaxy. This non-detection suggests that the particularly harsh environment of Trumpler 14 is too brutal for disks within it to survive.These observations provide new clues as to where we should be looking to study planet formation: less dense regions in star-forming nebulae seem to be locations that can support giant-planet-forming disks, whereas the harsh radiation fields of especially dense subclusters seem to cause the rapid destruction of such disks.CitationA. Mesa-Delgado et al 2016 ApJ 825 L16. doi:10.3847/2041-8205/825/1/L16

  20. Optical Navigation for the Orion Vehicle

    Science.gov (United States)

    Crain, Timothy; Getchius, Joel; D'Souza, Christopher

    2008-01-01

    The Orion vehicle is being designed to provide nominal crew transport to the lunar transportation stack in low Earth orbit, crew abort prior during transit to the moon, and crew return to Earth once lunar orbit is achieved. One of the design requirements levied on the Orion vehicle is the ability to return to the vehicle and crew to Earth in the case of loss of communications and command with the Mission Control Center. Central to fulfilling this requirement, is the ability of Orion to navigate autonomously. In low-Earth orbit, this may be solved with the use of GPS, but in cis-lunar and lunar orbit this requires optical navigation. This paper documents the preliminary analyses performed by members of the Orion Orbit GN&C System team.

  1. Compression and ablation of the photo-irradiated molecular cloud the Orion Bar

    Science.gov (United States)

    Goicoechea, Javier R.; Pety, Jérôme; Cuadrado, Sara; Cernicharo, José; Chapillon, Edwige; Fuente, Asunción; Gerin, Maryvonne; Joblin, Christine; Marcelino, Nuria; Pilleri, Paolo

    2016-09-01

    The Orion Bar is the archetypal edge-on molecular cloud surface illuminated by strong ultraviolet radiation from nearby massive stars. Our relative closeness to the Orion nebula (about 1,350 light years away from Earth) means that we can study the effects of stellar feedback on the parental cloud in detail. Visible-light observations of the Orion Bar show that the transition between the hot ionized gas and the warm neutral atomic gas (the ionization front) is spatially well separated from the transition between atomic and molecular gas (the dissociation front), by about 15 arcseconds or 6,200 astronomical units (one astronomical unit is the Earth-Sun distance). Static equilibrium models used to interpret previous far-infrared and radio observations of the neutral gas in the Orion Bar (typically at 10-20 arcsecond resolution) predict an inhomogeneous cloud structure comprised of dense clumps embedded in a lower-density extended gas component. Here we report one-arcsecond-resolution millimetre-wave images that allow us to resolve the molecular cloud surface. In contrast to stationary model predictions, there is no appreciable offset between the peak of the H2 vibrational emission (delineating the H/H2 transition) and the edge of the observed CO and HCO+ emission. This implies that the H/H2 and C+/C/CO transition zones are very close. We find a fragmented ridge of high-density substructures, photoablative gas flows and instabilities at the molecular cloud surface. The results suggest that the cloud edge has been compressed by a high-pressure wave that is moving into the molecular cloud, demonstrating that dynamical and non-equilibrium effects are important for the cloud evolution.

  2. Circumbinary Molecular Rings Around Young Stars in Orion

    CERN Document Server

    Zapata, Luis A; Rodriguez, Luis F; Schilke, Peter; Kurtz, Stan

    2007-01-01

    We present high angular resolution 1.3 mm continuum, methyl cyanide molecular line, and 7 mm continuum observations made with the Submillimeter Array and the Very Large Array, toward the most highly obscured and southern part of the massive star forming region OMC1S located behind the Orion Nebula. We find two flattened and rotating molecular structures with sizes of a few hundred astronomical units suggestive of circumbinary molecular rings produced by the presence of two stars with very compact circumstellar disks with sizes and separations of about 50 AU, associated with the young stellar objects 139-409 and 134-411. Furthermore, these two circumbinary rotating rings are related to two compact and bright {\\it hot molecular cores}. The dynamic mass of the binary systems obtained from our data are $\\geq$ 4 M$_\\odot$ for 139-409 and $\\geq$ 0.5 M$_\\odot$ for 134-411. This result supports the idea that intermediate-mass stars will form through {\\it circumstellar disks} and jets/outflows, as the low mass stars d...

  3. Orion Suit Loop Variable Pressure Regulator Development

    Science.gov (United States)

    Mosher, Michael; Vassallo, Andrew; Lewis, John F.; Campbell, Melissa

    2014-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) integrates the cabin and pressure suits with the core life support systems to provide life support during contingency depressurized cabin operations. To provide the multipule suit pressures between nominal pressurized cabin suited operations, suit leak checks, depressurized cabin suited operations, and elevated suit pressure for denitrification, a variable pressure regulator is needed. This paper documents the development and integrated testing of the suit loop regulator for Orion.

  4. Distances from Planetary Nebulae

    CERN Document Server

    Ciardullo, R

    2003-01-01

    The [O III] 5007 planetary nebula luminosity function (PNLF) occupies an important place on the extragalactic distance ladder. Since it is the only method that is applicable to all the large galaxies of the Local Supercluster, it is uniquely useful for cross-checking results and linking the Population I and Population II distance scales. We review the physics underlying the method, demonstrate its precision, and illustrate its value by comparing its distances to distances obtained from Cepheids and the Surface Brightness Fluctuation (SBF) method. We use the Cepheid and PNLF distances to 13 galaxies to show that the metallicity dependence of the PNLF cutoff is in excellent agreement with that predicted from theory, and that no additional systematic corrections are needed for either method. However, when we compare the Cepheid-calibrated PNLF distance scale with the Cepheid-calibrated SBF distance scale, we find a significant offset: although the relative distances of both methods are in excellent agreement, th...

  5. Scaled Eagle Nebula Experiments on NIF

    Energy Technology Data Exchange (ETDEWEB)

    Pound, Marc

    2017-03-28

    We performed scaled laboratory experiments at the National Ignition Facility laser to assess models for the creation of pillar structures in star-forming clouds of molecular hydrogen, in particular the famous Pillars of the Eagle Nebula. Because pillars typically point towards nearby bright ultraviolet stars, sustained directional illumination appears to be critical to pillar formation. The experiments mock up illumination from a cluster of ultraviolet-emitting stars, using a novel long duration (30--60 ns), directional, laser-driven x-ray source consisting of multiple radiation cavities illuminated in series. Our pillar models are assessed using the morphology of the Eagle Pillars observed with the Hubble Space Telescope, and measurements of column density and velocity in Eagle Pillar II obtained at the BIMA and CARMA millimeter wave facilities. In the first experiments we assess a shielding model for pillar formation. The experimental data suggest that a shielding pillar can match the observed morphology of Eagle Pillar II, and the observed Pillar II column density and velocity, if augmented by late time cometary growth.

  6. Embedded Star Formation in the Eagle Nebula

    CERN Document Server

    Thompson, R I; Hester, J J; Thompson, Rodger I.; Smith, Bradford A.

    2002-01-01

    M16=NGC 6611, the Eagle Nebula, is a well studied region of star formation and the source of a widely recognized Hubble Space Telescope (HST) image. High spatial resolution infrared observations with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on HST reveal the detailed morphology of two embedded star formation regions that are heavily obscured at optical wavelengths. It is striking that only limited portions of the visually obscured areas are opaque at 2.2 microns. Although the optical images imply substantial columns of material, the infrared images show only isolated clumps of dense gas and dust. Rather than being an active factory of star production, only a few regions are capable of sustaining current star formation. Most of the volume in the columns may be molecular gas and dust, protected by capstones of dense dust. Two active regions of star formation are located at the tips of the optical northern and central large ``elephant trunk'' features shown in the WFPC2 images. They are em...

  7. Molecular studies of Planetary Nebulae

    OpenAIRE

    Zhang, Yong

    2016-01-01

    Circumstellar envelopes (CEs) around evolved stars are an active site for the production of molecules. After evolving through the Asymptotic Giant Branch (AGB), proto-planetary nebula (PPN), to planetary nebula (PN) phases, CEs ultimately merge with the interstellar medium (ISM). The study of molecules in PNe, therefore, is essential to understanding the transition from stellar to interstellar materials. So far, over 20 molecular species have been discovered in PNe. The molecular composition ...

  8. A Spitzer Census of the IC 348 Nebula

    Science.gov (United States)

    Muench, August A.; Lada, Charles J.; Luhman, K. L.; Muzerolle, James; Young, Erick

    2007-07-01

    Spitzer mid-infrared surveys enable an accurate census of young stellar objects by sampling large spatial scales, revealing very embedded protostars, and detecting low-luminosity objects. Taking advantage of these capabilities, we present a Spitzer-based census of the IC 348 nebula and embedded star cluster, covering a 2.5 pc region and comparable in extent to the Orion Nebula. Our Spitzer census supplemented with ground-based spectra has added 42 Class II T Tauri sources to the cluster membership and identified ~20 Class 0/I protostars. The population of IC 348 likely exceeds 400 sources after accounting statistically for unidentified diskless members. Our Spitzer census of IC 348 reveals a population of Class I protostars that is anticorrelated spatially with the Class II/III T Tauri members, which comprise the centrally condensed cluster around a B star. The protostars are instead found mostly at the cluster periphery about ~1 pc from the B star and spread out along a filamentary ridge. We further find that the star formation rate in this protostellar ridge is consistent with that rate which built the older exposed cluster, while the presence of 15 cold, starless, millimeter cores intermingled with this protostellar population indicates that the IC 348 nebula has yet to finish forming stars. Moreover, we show that the IC 348 cluster is of order 3-5 crossing times old, and, as evidenced by its smooth radial profile and confirmed mass segregation, is likely relaxed. While it seems apparent that the current cluster configuration is the result of dynamical evolution and its primordial structure has been erased, our finding of a filamentary ridge of Class I protostars supports a model in which embedded clusters are built up from numerous smaller subclusters. Finally, the results of our Spitzer census indicate that the supposition that star formation must progress rapidly in a dark cloud should not preclude these observations that show it can be relatively long lived.

  9. Orion Entry Handling Qualities Assessments

    Science.gov (United States)

    Bihari, B.; Tiggers, M.; Strahan, A.; Gonzalez, R.; Sullivan, K.; Stephens, J. P.; Hart, J.; Law, H., III; Bilimoria, K.; Bailey, R.

    2011-01-01

    The Orion Command Module (CM) is a capsule designed to bring crew back from the International Space Station (ISS), the moon and beyond. The atmospheric entry portion of the flight is deigned to be flown in autopilot mode for nominal situations. However, there exists the possibility for the crew to take over manual control in off-nominal situations. In these instances, the spacecraft must meet specific handling qualities criteria. To address these criteria two separate assessments of the Orion CM s entry Handling Qualities (HQ) were conducted at NASA s Johnson Space Center (JSC) using the Cooper-Harper scale (Cooper & Harper, 1969). These assessments were conducted in the summers of 2008 and 2010 using the Advanced NASA Technology Architecture for Exploration Studies (ANTARES) six degree of freedom, high fidelity Guidance, Navigation, and Control (GN&C) simulation. This paper will address the specifics of the handling qualities criteria, the vehicle configuration, the scenarios flown, the simulation background and setup, crew interfaces and displays, piloting techniques, ratings and crew comments, pre- and post-fight briefings, lessons learned and changes made to improve the overall system performance. The data collection tools, methods, data reduction and output reports will also be discussed. The objective of the 2008 entry HQ assessment was to evaluate the handling qualities of the CM during a lunar skip return. A lunar skip entry case was selected because it was considered the most demanding of all bank control scenarios. Even though skip entry is not planned to be flown manually, it was hypothesized that if a pilot could fly the harder skip entry case, then they could also fly a simpler loads managed or ballistic (constant bank rate command) entry scenario. In addition, with the evaluation set-up of multiple tasks within the entry case, handling qualities ratings collected in the evaluation could be used to assess other scenarios such as the constant bank angle

  10. Differential Proper-Motion Measurements of The Cygnus Egg Nebula: The Presence of Equatorial Outflow

    CERN Document Server

    Ueta, Toshiya; Ferguson, Brian A

    2013-01-01

    We present the results of differential proper-motion analyses of the Egg Nebula (RAFGL 2688, V1610 Cyg) based on the archived two-epoch optical data taken with the Hubble Space Telescope. First, we determined that the polarization characteristics of the Egg Nebula is influenced by the higher optical depth of the central regions of the nebula (i.e., the "dustsphere" of about 1000 AU radius), causing the nebula illuminated in two steps -- the direct starlight is first channeled into bipolar cavities and then scattered off to the rest of the nebula. We then measured the amount of motion of local structures and the signature concentric arcs by determining their relative shifts over the 7.25 yr interval. Based on our analysis, which does not rely on the single-scattering assumption, we concluded that the lobes have been excavated by a linear expansion along the bipolar axis for the past 400 yr, while the concentric arcs have been generated continuously and moving out radially at about 10 km/s for the past 5,500 yr...

  11. Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. I. Observational Overview and First Results

    Science.gov (United States)

    Sabbi, E.; Anderson, J.; Lennon, D. J.; van der Marel, R. P.; Aloisi, A.; Boyer, Martha L.; Cignoni, M.; De Marchi, G.; De Mink, S. E.; Evans, C. J.; hide

    2013-01-01

    The Hubble Tarantula Treasury Project (HTTP) is an ongoing panchromatic imaging survey of stellar populations in the Tarantula Nebula in the Large Magellanic Cloud that reaches into the sub-solar mass regime (Hubble Space Telescope to operate the Advanced Camera for Surveys and the Wide Field Camera 3 in parallel to study this remarkable region in the near-ultraviolet, optical, and near-infrared spectral regions, including narrow-band H(alpha) images. The combination of all these bands provides a unique multi-band view. The resulting maps of the stellar content of the Tarantula Nebula within its main body provide the basis for investigations of star formation in an environment resembling the extreme conditions found in starburst galaxies and in the early universe. Access to detailed properties of individual stars allows us to begin to reconstruct the temporal and spatial evolution of the stellar skeleton of the Tarantula Nebula over space and time on a sub-parsec scale. In this first paper we describe the observing strategy, the photometric techniques, and the upcoming data products from this survey and present preliminary results obtained from the analysis of the initial set of near-infrared observations.

  12. HUBBLE TARANTULA TREASURY PROJECT: UNRAVELING TARANTULA'S WEB. I. OBSERVATIONAL OVERVIEW AND FIRST RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Sabbi, E.; Anderson, J.; Van der Marel, R. P.; Aloisi, A.; De Mink, S. E.; Gordon, K.; Koekemoer, A. M.; Panagia, N. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Lennon, D. J. [ESA-European Space Astronomy Center, Apdo. de Correo 78, E-28691 Villanueva de la Canada, Madrid (Spain); Boyer, M. L. [Observational Cosmology Lab, Code 665, NASA, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Cignoni, M. [Dipartimento di Astronomia, Universita degli Studi di Bologna, via Ranzani, I-40127 Bologna (Italy); De Marchi, G. [Space Science Department, European Space Agency, Keplerlaan 1, 2200-AG Noordwijk (Netherlands); Evans, C. J. [UK Astronomy Technology Center, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Gallagher, J. S. III; Ryon, J. E. [Department of Astronomy, University of Wisconsin, 475 North Charter Street, Madison, WI 53706 (United States); Gouliermis, D. A. [Zentrum fuer Astronomie, Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Grebel, E. K. [Zentrum fuer Astronomie, Astronomisches Rechen-Institut, Universitaet Heidelberg, Moenchhofstr. 12-14, D-69120 Heidelberg (Germany); Larsen, S. S. [Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500-GL Nijmegen (Netherlands); Smith, L. J. [ESA/STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Tosi, M., E-mail: sabbi@stsci.edu [Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); and others

    2013-09-15

    The Hubble Tarantula Treasury Project (HTTP) is an ongoing panchromatic imaging survey of stellar populations in the Tarantula Nebula in the Large Magellanic Cloud that reaches into the sub-solar mass regime (<0.5 M{sub Sun }). HTTP utilizes the capability of the Hubble Space Telescope to operate the Advanced Camera for Surveys and the Wide Field Camera 3 in parallel to study this remarkable region in the near-ultraviolet, optical, and near-infrared spectral regions, including narrow-band H{alpha} images. The combination of all these bands provides a unique multi-band view. The resulting maps of the stellar content of the Tarantula Nebula within its main body provide the basis for investigations of star formation in an environment resembling the extreme conditions found in starburst galaxies and in the early universe. Access to detailed properties of individual stars allows us to begin to reconstruct the temporal and spatial evolution of the stellar skeleton of the Tarantula Nebula over space and time on a sub-parsec scale. In this first paper we describe the observing strategy, the photometric techniques, and the upcoming data products from this survey and present preliminary results obtained from the analysis of the initial set of near-infrared observations.

  13. Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. I. Observational Overview and First Results

    Science.gov (United States)

    Sabbi, E.; Anderson, J.; Lennon, D. J.; van der Marel, R. P.; Aloisi, A.; Boyer, M. L.; Cignoni, M.; de Marchi, G.; de Mink, S. E.; Evans, C. J.; Gallagher, J. S., III; Gordon, K.; Gouliermis, D. A.; Grebel, E. K.; Koekemoer, A. M.; Larsen, S. S.; Panagia, N.; Ryon, J. E.; Smith, L. J.; Tosi, M.; Zaritsky, D.

    2013-09-01

    The Hubble Tarantula Treasury Project (HTTP) is an ongoing panchromatic imaging survey of stellar populations in the Tarantula Nebula in the Large Magellanic Cloud that reaches into the sub-solar mass regime (images. The combination of all these bands provides a unique multi-band view. The resulting maps of the stellar content of the Tarantula Nebula within its main body provide the basis for investigations of star formation in an environment resembling the extreme conditions found in starburst galaxies and in the early universe. Access to detailed properties of individual stars allows us to begin to reconstruct the temporal and spatial evolution of the stellar skeleton of the Tarantula Nebula over space and time on a sub-parsec scale. In this first paper we describe the observing strategy, the photometric techniques, and the upcoming data products from this survey and present preliminary results obtained from the analysis of the initial set of near-infrared observations. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA Inc., under NASA contract NAS 5-26555.

  14. Hubble Tarantula Treasury Project. IV. The extinction law

    CERN Document Server

    De Marchi, Guido; Sabbi, Elena; Lennon, Daniel; Anderson, Jay; van der Marel, Roeland; Cignoni, Michele; Grebel, Eva K; Larsen, Soeren; Zaritsky, Dennis; Zeidler, Peter; Gouliermis, Dimitrios; Aloisi, Alessandra

    2015-01-01

    We report on the study of interstellar extinction across the Tarantula nebula (30 Doradus), in the Large Magellanic Cloud, using observations from the Hubble Tarantula Treasury Project in the 0.3 - 1.6 micron range. The considerable and patchy extinction inside the nebula causes about 3500 red clump stars to be scattered along the reddening vector in the colour-magnitude diagrams, thereby allowing an accurate determination of the reddening slope in all bands. The measured slope of the reddening vector is remarkably steeper in all bands than in the the Galactic diffuse interstellar medium. At optical wavelengths, the larger ratio of total-to-selective extinction, namely Rv = 4.5 +/- 0.2, implies the presence of a grey component in the extinction law, due to a larger fraction of large grains. The extra large grains are most likely ices from supernova ejecta and will significantly alter the extinction properties of the region until they sublimate in 50 - 100 Myr. We discuss the implications of this extinction la...

  15. Planck Scale to Hubble Scale

    CERN Document Server

    Sidharth, B G

    1998-01-01

    Within the context of the usual semi classical investigation of Planck scale Schwarzchild Black Holes, as in Quantum Gravity, and later attempts at a full Quantum Mechanical description in terms of a Kerr-Newman metric including the spinorial behaviour, we attempt to present a formulation that extends from the Planck scale to the Hubble scale. In the process the so called large number coincidences as also the hitherto inexplicable relations between the pion mass and the Hubble Constant, pointed out by Weinberg, turn out to be natural consequences in a consistent description.

  16. Jet driven molecular outflows in Orion

    CERN Document Server

    Rodríguez-Franco, A; Wilson, T L

    1999-01-01

    We present high sensitivity and high angular resolution images of the high velocity (vLSR>30kms^-1) CO emission in the J=1-0 and J=2-1 lines of the Orion KL region. These results reveal the morphology of the high-velocity CO emission at the most extreme velocities. High velocity emission have been only detected in two regions: BN/KL (IRc2/I) and Orion-S. The Orion-S region contains a very young (dynamical age of 10^3years), very fast (~110kms^-1) and very compact (<0.16pc) bipolar outflow. From the morphology of the high-velocity gas we estimate that the position of the powering source must be ~20'' north of FIR4. For the IRc2/I molecular outflow the morphology of the moderate velocity (<60kms^-1) gas shows a weak bipolarity around IRc2/I. The gas at the most extreme velocities does not show any bipolarity around IRc2/I, if any, it is found ~30'' north from these sources. The blue and redshifted gas at moderate velocities shows similar spatial distribution with a systematic trend for the size of the hig...

  17. Kennedy Space Center Orion Processing Team Planning for Ground Operations

    Science.gov (United States)

    Letchworth, Gary; Schlierf, Roland

    2011-01-01

    Topics in this presentation are: Constellation Ares I/Orion/Ground Ops Elements Orion Ground Operations Flow Orion Operations Planning Process and Toolset Overview, including: 1 Orion Concept of Operations by Phase 2 Ops Analysis Capabilities Overview 3 Operations Planning Evolution 4 Functional Flow Block Diagrams 5 Operations Timeline Development 6 Discrete Event Simulation (DES) Modeling 7 Ground Operations Planning Document Database (GOPDb) Using Operations Planning Tools for Operability Improvements includes: 1 Kaizen/Lean Events 2 Mockups 3 Human Factors Analysis

  18. New infrared observations of IRS1, IRS3, and the adjacent nebula in the OMC-2 cluster

    Science.gov (United States)

    Pendleton, Y.; Werner, M.; Capps, R.; Dinerstein, H. L.

    1984-01-01

    Observations of the infrared cluster of low luminosity protostars in Orion Molecular Cloud 2 (OMC2) are reported. Results show that the asymmetric distribution of the extended emission seen about IRS1 is another infrared reflection nebula. Energy distributions show that the spectral shape is fairly constant throughout the nebula which indicates there is little internal extinction within this region. Integrated surface brightness values show that the nebula is 5 times brighter than IRS1 at K. Energy distributions show that IRS1 has a more pronounced ice band absorption feature at 3.1 micron; suggesting that there is more extinction along the direct line of sight to IRS1 than along a line from IRS1 to the scattering grains and then to the observer. The distribution of the extended emission around IRS1 is similar to the reflection nebula seen in NGC 7538 (Werner et al. 1979). The asymmetric shapes of the two nebulae are similar and in each case there is excess extinction along line of sight to the illuminating source.

  19. New infrared observations of IRS1, IRS3, and the adjacent nebula in the OMC-2 cluster

    Science.gov (United States)

    Pendleton, Y.; Werner, M.; Capps, R.; Dinerstein, H. L.

    1984-01-01

    Observations of the infrared cluster of low luminosity protostars in Orion Molecular Cloud 2 (OMC2) are reported. Results show that the asymmetric distribution of the extended emission seen about IRS1 is another infrared reflection nebula. Energy distributions show that the spectral shape is fairly constant throughout the nebula which indicates there is little internal extinction within this region. Integrated surface brightness values show that the nebula is 5 times brighter than IRS1 at K. Energy distributions show that IRS1 has a more pronounced ice band absorption feature at 3.1 micron; suggesting that there is more extinction along the direct line of sight to IRS1 than along a line from IRS1 to the scattering grains and then to the observer. The distribution of the extended emission around IRS1 is similar to the reflection nebula seen in NGC 7538 (Werner et al. 1979). The asymmetric shapes of the two nebulae are similar and in each case there is excess extinction along line of sight to the illuminating source.

  20. Pulsar Wind Nebulae Modeling

    CERN Document Server

    Bucciantini, N

    2013-01-01

    Pulsar Wind Nebulae (PWNe) are ideal astrophysical laboratories where high energy relativistic phenomena can be investigated. They are close, well resolved in our observations, and the knowledge derived in their study has a strong impact in many other fields, from AGNs to GRBs. Yet there are still unresolved issues, that prevent us from a full clear understanding of these objects. The lucky combination of high resolution X-ray imaging and numerical codes to handle the outflow and dynamical properties of relativistic MHD, has opened a new avenue of investigation that has lead to interesting progresses in the last years. Despite all of this, we do not understand yet how particles are accelerated, and the functioning of the pulsar wind and pulsar magnetosphere, that power PWNe. I will review what is now commonly known as the MHD paradigm, and in particular I will focus on various approaches that have been and are currently used to model these systems. For each I will highlight its advantages, limitations, and de...

  1. Crew Exploration Vehicle (CEV) (Orion) Occupant Protection

    Science.gov (United States)

    Currie-Gregg, Nancy J.; Gernhardt, Michael L.; Lawrence, Charles; Somers, Jeffrey T.

    2016-01-01

    Dr. Nancy J. Currie, of the NASA Engineering and Safety Center (NESC), Chief Engineer at Johnson Space Center (JSC), requested an assessment of the Crew Exploration Vehicle (CEV) occupant protection as a result of issues identified by the Constellation Program and Orion Project. The NESC, in collaboration with the Human Research Program (HRP), investigated new methods associated with occupant protection for the Crew Exploration Vehicle (CEV), known as Orion. The primary objective of this assessment was to investigate new methods associated with occupant protection for the CEV, known as Orion, that would ensure the design provided minimal risk to the crew during nominal and contingency landings in an acceptable set of environmental and spacecraft failure conditions. This documents contains the outcome of the NESC assessment. NASA/TM-2013-217380, "Application of the Brinkley Dynamic Response Criterion to Spacecraft Transient Dynamic Events." supercedes this document.

  2. Orion Spacecraft MMOD Protection Design and Assessment

    Science.gov (United States)

    Bohl, William; Miller, Joshua; Deighton, Kevin; Foreman, Cory; Yasensky, John; Christiansen, Eric; Hyde, James; Nahra, Henry

    2009-01-01

    The Orion spacecraft will replace the Space Shuttle Orbiter for American and international partner access to the International Space Station by 2015 and, afterwards, for access to the moon for initial sorties and later for extend outpost visits as part of the Constellation Exploration Initiative. This work describes some of the efforts being undertaken to ensure that Orion design will meet or exceed the stringent MicroMeteoroid and Orbital Debris (MMOD) requirements set out by NASA when exposed to the environments encountered with these missions. This paper will provide a brief overview of the approaches being used to provide MMOD protection to the Orion vehicle and to assess the spacecraft for compliance to the Constellation Program s MMOD requirements.

  3. Revised Diagnostic Diagrams for Planetary Nebulae

    CERN Document Server

    Riesgo, H

    2006-01-01

    Diagnostic diagrams of electron density - excitation for a sample of 613 planetary nebulae are presented. The present extensive sample allows the definition of new statistical limits for the distribution of planetary nebulae in the log [Ha/[SII

  4. The Orion OB1 Association II. The Orion-Eridanus Bubble

    OpenAIRE

    Brown, A. G. A.; Hartmann, D; Burton, W. B.

    1995-01-01

    Observations of the interstellar medium in the vicinity of the Orion OB1 association show a cavity filled with hot ionized gas, surrounded by an expanding shell of neutral hydrogen (the Orion-Eridanus Bubble). In this paper we examine this cavity and the surrounding bubble with the aid of data from the Leiden/Dwingeloo HI survey. We present neutral-hydrogen maps for the Orion-Eridanus region which allow identification of the HI filaments and arcs delineating the Bubble and derivation of its e...

  5. The age of the universe, the Hubble constant, the accelerated expansion and the Hubble effect

    OpenAIRE

    Soares,Domingos

    2009-01-01

    The idea of an accelerating universe comes almost simultaneously with the determination of Hubble's constant by one of the Hubble Space Telescope Key Projects. The age of the universe dilemma is probably the link between these two issues. In an appendix, I claim that "Hubble's law" might yet to be investigated for its ultimate cause, and suggest the "Hubble effect" as the searched candidate.

  6. The age of the universe, the Hubble constant, the accelerated expansion and the Hubble effect

    OpenAIRE

    Soares, Domingos

    2009-01-01

    The idea of an accelerating universe comes almost simultaneously with the determination of Hubble's constant by one of the Hubble Space Telescope Key Projects. The age of the universe dilemma is probably the link between these two issues. In an appendix, I claim that "Hubble's law" might yet to be investigated for its ultimate cause, and suggest the "Hubble effect" as the searched candidate.

  7. Stellar Activity on the Young Suns of Orion: COUP Observations of K5-7 Pre-Main Sequence Stars

    CERN Document Server

    Wolk, S J; Micela, G; Favata, F; Glassgold, A E; Shang, H; Feigelson, E D

    2005-01-01

    In January 2003, the Chandra Orion Ultradeep Project (COUP) detected about 1400 young stars during a 13.2 day observation of the Orion Nebula Cluster (ONC). This paper studies a well-defined sample of 28 solar-mass COUP sources to characterize the magnetic activity of analogs of the young Sun and thereby to improve understanding of the effects of solar X-rays on the solar nebula during the era of planet formation. We find that active young Suns spend 70% of their time in a characteristic state with relatively constant flux and magnetically confined plasma with temperatures kT_2 = 2.1 * kT_1. During characteristic periods, the 0.5-8 keV X-ray luminosity is about 0.03% of the bolometric luminosity. One or two powerful flares per week with peak luminosities logL_x ~ 30-32 erg/s are typically superposed on this characteristic emission accompanied by heating of the hot plasma component from ~2.4 keV to ~7 keV at the flare peak. The energy distribution of flares superposed on the characteristic emission level follo...

  8. The 1% concordance Hubble constant

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, C. L.; Larson, D.; Weiland, J. L. [Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Hinshaw, G., E-mail: cbennett@jhu.edu [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)

    2014-10-20

    The determination of the Hubble constant has been a central goal in observational astrophysics for nearly a hundred years. Extraordinary progress has occurred in recent years on two fronts: the cosmic distance ladder measurements at low redshift and cosmic microwave background (CMB) measurements at high redshift. The CMB is used to predict the current expansion rate through a best-fit cosmological model. Complementary progress has been made with baryon acoustic oscillation (BAO) measurements at relatively low redshifts. While BAO data do not independently determine a Hubble constant, they are important for constraints on possible solutions and checks on cosmic consistency. A precise determination of the Hubble constant is of great value, but it is more important to compare the high and low redshift measurements to test our cosmological model. Significant tension would suggest either uncertainties not accounted for in the experimental estimates or the discovery of new physics beyond the standard model of cosmology. In this paper we examine in detail the tension between the CMB, BAO, and cosmic distance ladder data sets. We find that these measurements are consistent within reasonable statistical expectations and we combine them to determine a best-fit Hubble constant of 69.6 ± 0.7 km s{sup –1} Mpc{sup –1}. This value is based upon WMAP9+SPT+ACT+6dFGS+BOSS/DR11+H {sub 0}/Riess; we explore alternate data combinations in the text. The combined data constrain the Hubble constant to 1%, with no compelling evidence for new physics.

  9. Contraction of the solar nebula

    Science.gov (United States)

    Rawal, J. J.

    1984-10-01

    The concept of Roche limit is applied to the Laplacian theory of the origin of the solar system to study the contraction of a spherical gas cloud (solar nebula). In the process of contraction of the solar nebula, it is assumed that the phenomenon of supersonic turbulent convection described by Prentice (1978) is operative. It is found that the radius of the contracting solar nebula follows Titius-Bode law Rp = R_sun; ap, where R_sun; is the radius of the present Sun and a = 1.442. The consequences of the relation are also discussed. The aim, here, is an attempt to explain, on the basis of the concept of Roche limit, the distribution of planets in the solar system and try to understand the physics underlying it.

  10. Extended High Circular Polarization in the Orion Massive Star Forming Region: Implications for the Origin of Homochirality in the Solar System

    CERN Document Server

    Fukue, Tsubasa; Kandori, Ryo; Kusakabe, Nobuhiko; Hough, James H; Bailey, Jeremy; Whittet, Douglas C B; Lucas, Philip W; Nakajima, Yasushi; Hashimoto, Jun

    2010-01-01

    We present a wide-field (~6'x6') and deep near-infrared (Ks band: 2.14 micro m) circular polarization image in the Orion nebula, where massive stars and many low-mass stars are forming. Our results reveal that a high circular polarization region is spatially extended (~0.4 pc) around the massive star-forming region, the BN/KL nebula. However, other regions, including the linearly polarized Orion bar, show no significant circular polarization. Most of the low-mass young stars do not show detectable extended structure in either linear or circular polarization, in contrast to the BN/KL nebula. If our solar system formed in a massive star-forming region and was irradiated by net circularly polarized radiation, then enantiomeric excesses could have been induced, through asymmetric photochemistry, in the parent bodies of the meteorites and subsequently delivered to Earth. These could then have played a role in the development of biological homochirality on Earth.

  11. Extended high circular polarization in the Orion massive star forming region: implications for the origin of homochirality in the solar system.

    Science.gov (United States)

    Fukue, Tsubasa; Tamura, Motohide; Kandori, Ryo; Kusakabe, Nobuhiko; Hough, James H; Bailey, Jeremy; Whittet, Douglas C B; Lucas, Philip W; Nakajima, Yasushi; Hashimoto, Jun

    2010-06-01

    We present a wide-field (approximately 6' x 6') and deep near-infrared (K(s) band: 2.14 mum) circular polarization image in the Orion nebula, where massive stars and many low-mass stars are forming. Our results reveal that a high circular polarization region is spatially extended (approximately 0.4 pc) around the massive star-forming region, the BN/KL nebula. However, other regions, including the linearly polarized Orion bar, show no significant circular polarization. Most of the low-mass young stars do not show detectable extended structure in either linear or circular polarization, in contrast to the BN/KL nebula. If our solar system formed in a massive star-forming region and was irradiated by net circularly polarized radiation, then enantiomeric excesses could have been induced, through asymmetric photochemistry, in the parent bodies of the meteorites and subsequently delivered to Earth. These could then have played a role in the development of biological homochirality on Earth.

  12. A 3D view of the outflow in the Orion Molecular Cloud 1 (OMC-1)

    CERN Document Server

    Nissen, H D; Gustafsson, M; Bally, J; Lemaire, J -L; Favre, C; Field, D

    2012-01-01

    The fast outflow emerging from a region associated with massive star formation in the Orion Molecular Cloud 1 (OMC-1), located behind the Orion Nebula, appears to have been set in motion by an explosive event. Here we study the structure and dynamics of outflows in OMC-1. We combine radial velocity and proper motion data for near-IR emission of molecular hydrogen to obtain the first 3-dimensional (3D) structure of the OMC-1 outflow. Our work illustrates a new diagnostic tool for studies of star formation that will be exploited in the near future with the advent of high spatial resolution spectro-imaging in particular with data from the Atacama Large Millimeter Array (ALMA). We use published radial and proper motion velocities obtained from the shock-excited vibrational emission in the H2 v=1-0 S(1) line at 2.122 $\\mu$m obtained with the GriF instrument on the Canada-France-Hawaii Telescope, the Apache Point Observatory, the Anglo-Australian Observatory and the Subaru Telescope. These data give the 3D velocity...

  13. Compact Radio Sources in Orion: New Detections, Time Variability, and Objects in OMC-1S

    CERN Document Server

    Zapata, L A; Kurtz, S E; O'Dell, C R; Zapata, Luis A.; Rodriguez, Luis F.; Kurtz, Stanley E.

    2004-01-01

    We present the analysis of four 3.6 cm radio continuum archival observations of Orion obtained using the Very Large Array in its A-configuration, with $0\\rlap.{''}3$ angular resolution. The observations were made during the period 1994-1997. In a region of $4' \\times 4'$, we detect a total of 77 compact radio sources. Of the total of detected sources, 54 are detected in one or more of the individual observations and 36 of these show time variability (by more than 30%) between the observed epochs. A deep image made from averaging all data shows an additional 23 faint sources, in the range of 0.1 to 0.3 mJy. Of the total of 77 sources, 39 are new centimeter detections. However, only 9 of the 77 sources do not have a previously reported counterpart at near-infrared, optical, or X-ray wavelengths. In particular, we detect three faint sources in the OMC-1S region that may be related to the sources that power the multiple outflows that emanate from this part of the Orion nebula. %We discuss the nature of these sour...

  14. Large-scale CO (J=4-3) Mapping toward the Orion-A Giant Molecular Cloud

    CERN Document Server

    Ishii, Shun; Nagai, Makoto; Miyamoto, Yusuke; Nakai, Naomasa; Nagasaki, Taketo; Arai, Hitoshi; Imada, Hiroaki; Miyagawa, Naoki; Maezawa, Hiroyuki; Maehashi, Hideki; Bronfman, Leonardo; Finger, Ricardo

    2015-01-01

    We have mapped the Orion-A Giant Molecular Cloud in the CO (J=4-3) line with the Tsukuba 30-cm submillimeter telescope.The map covered a 7.125 deg^2 area with a 9' resolution, including main components of the cloud such as Orion Nebula, OMC-2/3, and L1641-N. The most intense emission was detected toward the Orion KL region. The integrated intensity ratio between CO (J=4-3) and CO (J=1-0) was derived using data from the Columbia-Univ. de Chile CO survey, which was carried out with a comparable angular resolution. The ratio was r_{4-3/1-0} ~ 0.2 in the southern region of the cloud and 0.4-0.8 at star forming regions. We found a trend that the ratio shows higher value at edges of the cloud. In particular the ratio at the north-eastern edge of the cloud at (l, b) = (208.375 deg, -19.0 deg) shows the specific highest value of 1.1. The physical condition of the molecular gas in the cloud was estimated by non-LTE calculation. The result indicates that the kinetic temperature has a gradient from north (Tkin=80 K) to ...

  15. Tangential Motions and Spectroscopy within NGC 6720, the Ring Nebula

    CERN Document Server

    O'Dell, C R; Sabbadin, F

    2009-01-01

    We have combined recent Hubble Space Telescope WFPC2 images in the [O III] 5007 and [N II] 6583 lines with similar images made 9.557 years earlier to determine the motion of the Ring Nebula within the plane of the sky. Scaled ratio images argue for homologous expansion, that is, larger velocities scale with increasing distance from the central star. The rather noisy pattern of motion of individual features argues for the same conclusion and that the silhouetted knots move at the same rate as the surrounding gas. These tangential velocities are combined with information from a recent high resolution radial velocity study to determine a dynamic distance, which is in basic agreement with the distance determined from the parallax of the central star. We have also obtained very high signal to noise ratio moderate resolution spectra (9.4 Angstrom) along the major and minor axes of the nebula and from this determined the electron temperatures and density in the multiple ionization zones present. These results confir...

  16. From AGB Stars to Aspherical Planetary Nebulae - An Observational Perspective

    Science.gov (United States)

    Sahai, R.

    2014-04-01

    Most stars that leave the main sequence in a Hubble time will end their lives, evolving through the Asymptotic Giant Branch (AGB), Preplanetary Nebula (PPN) and Planetary Nebula (PN) evolutionary phases. The heavy mass loss which occurs during the AGB phase is important across astrophysics, dramatically changing the course of stellar evolution, dominantly contributing to the dust content of the interstellar medium, and influencing its chemical composition. Yet stellar evolution from the beginning of the AGB phase to the PN phase remains poorly understood, especially the dramatic transformation that occurs in the morphology of the mass-ejecta as AGB stars and their round circumstellar envelopes evolve into mostly PNe, the majority of which deviate strongly from spherical symmetry. In this review, I describe the observations, spanning the wavelength range from X-rays to millimeter wavelengths, that have contributed to our current understanding of the physical processes responsible for the formation of aspherical PNe. I conclude by a brief summary of future observations using current and upcoming facilities such as HST, Chandra, ALMA and JWST that can help in addressing the major unsolved problems in the study of aspherical PNe.

  17. The Dispersed Young Population in Orion

    CERN Document Server

    Briceno, Cesar

    2008-01-01

    The Orion OB1 Association, at a distance of roughly 400 pc and spanning over ~200 deg^2 on the sky, is one of the largest and nearest OB associations. With a wide range of ages and environmental conditions, Orion is an ideal laboratory for investigating fundamental questions related to the birth of stars and planetary systems. This rich region exhibits all stages of the star formation process, from very young, embedded clusters, to older, fully exposed young stars; it also harbors dense clusters and widely spread populations in vast, low stellar density areas. This review focuses on the later, namely, the low-mass (M ~< 2 Mo), pre-main sequence population spread over wide spatial scales in Orion OB1, mostly in the off-cloud areas. As ongoing studies yield more complete censa it becomes clearer that this "distributed" or non-clustered population, is as numerous as that located in the molecular clouds; modern studies of star formation in Orion would be incomplete if they did not include this widely spread po...

  18. Integrated Network Architecture for NASA's Orion Missions

    Science.gov (United States)

    Bhasin, Kul B.; Hayden, Jeffrey L.; Sartwell, Thomas; Miller, Ronald A.; Hudiburg, John J.

    2008-01-01

    NASA is planning a series of short and long duration human and robotic missions to explore the Moon and then Mars. The series of missions will begin with a new crew exploration vehicle (called Orion) that will initially provide crew exchange and cargo supply support to the International Space Station (ISS) and then become a human conveyance for travel to the Moon. The Orion vehicle will be mounted atop the Ares I launch vehicle for a series of pre-launch tests and then launched and inserted into low Earth orbit (LEO) for crew exchange missions to the ISS. The Orion and Ares I comprise the initial vehicles in the Constellation system of systems that later includes Ares V, Earth departure stage, lunar lander, and other lunar surface systems for the lunar exploration missions. These key systems will enable the lunar surface exploration missions to be initiated in 2018. The complexity of the Constellation system of systems and missions will require a communication and navigation infrastructure to provide low and high rate forward and return communication services, tracking services, and ground network services. The infrastructure must provide robust, reliable, safe, sustainable, and autonomous operations at minimum cost while maximizing the exploration capabilities and science return. The infrastructure will be based on a network of networks architecture that will integrate NASA legacy communication, modified elements, and navigation systems. New networks will be added to extend communication, navigation, and timing services for the Moon missions. Internet protocol (IP) and network management systems within the networks will enable interoperability throughout the Constellation system of systems. An integrated network architecture has developed based on the emerging Constellation requirements for Orion missions. The architecture, as presented in this paper, addresses the early Orion missions to the ISS with communication, navigation, and network services over five

  19. Hubble Space Telescope NICMOS Polarization Measurements of OMC-1

    CERN Document Server

    Simpson, J P; Colgan, S W J; Erickson, E F; Schultz, A S B; Burton, Michael G.; Colgan, Sean W. J.; Erickson, Edwin F.; Simpson, Janet P.

    2006-01-01

    We present 2micron polarization measurements of positions in the BN region of the Orion Molecular Cloud (OMC-1) made with NICMOS Camera 2 (0.2'' resolution) on HST. Our results are as follows: BN is sim 29% polarized by dichroic absorption and appears to be the illuminating source for most of the nebulosity to its north and up to sim 5'' to its south. Although the stars are probably all polarized by dichroic absorption, there are a number of compact, but non-point-source, objects that could be polarized by a combination of both dichroic absorption and local scattering of star light. We identify several candidate YSOs, including an approximately edge-on bipolar YSO 8.7'' east of BN, and a deeply-embedded variable star. Additional strongly polarized sources are IRc2-B, IRc2-D, and IRc7, all of which are obviously self-luminous at mid-infrared wavelengths and may be YSOs. None of these is a reflection nebula illuminated by a star located near radio source I, as was previously suggested. Other IRc sources are cle...

  20. Hubble Law: Measure and Interpretation

    Science.gov (United States)

    Paturel, Georges; Teerikorpi, Pekka; Baryshev, Yurij

    2017-09-01

    We have had the chance to live through a fascinating revolution in measuring the fundamental empirical cosmological Hubble law. The key progress is analysed: (1) improvement of observational means (ground-based radio and optical observations, space missions); (2) understanding of the biases that affect both distant and local determinations of the Hubble constant; (3) new theoretical and observational results. These circumstances encourage us to take a critical look at some facts and ideas related to the cosmological red-shift. This is important because we are probably on the eve of a new understanding of our Universe, heralded by the need to interpret some cosmological key observations in terms of unknown processes and substances.

  1. Hubble multi-scalar inflation

    CERN Document Server

    Abedi, Habib

    2016-01-01

    Multiple field models of inflation exhibit new features than single field models. In this work, we study the hierarchy of parameters based on Hubble expansion rate in curved field space and derive the system of flow equations that describe their evolution. Then we focus on obtaining derivatives of number of $e$-folds with respect to scalar fields during inflation and at hypersurface of the end of inflation.

  2. Photometry of the Stingray Nebula (V839 Ara) from 1889-2015 Across the Ionization of Its Planetary Nebula

    CERN Document Server

    Schaefer, Bradley E

    2015-01-01

    Up until around 1980, the Stingray was an ordinary B1 post-AGB star, but then it suddenly sprouted bright emission lines like in a planetary nebula (PN), and soon after this the Hubble Space Telescope (HST) discovered a small PN around the star, so apparently we have caught a star in the act of ionizing a PN. We report here on a well-sampled light curve from 1889 to 2015, with unique coverage of the prior century plus the entire duration of the PN formation plus three decades of its aftermath. Surprisingly, the star anticipated the 1980's ionization event by declining from B=10.30 in 1889 to B=10.76 in 1980. Starting in 1980, the central star faded fast, at a rate of 0.20 mag/year, reaching B=14.64 in 1996. This fast fading is apparently caused by the central star shrinking in size. From 1994-2015, the V-band light curve is almost entirely from the flux of two bright [OIII] emission lines from the unresolved nebula, and it shows a consistent decline at a rate of 0.090 mag/year. This steady fading (also seen i...

  3. The Hubble Catalog of Variables

    Science.gov (United States)

    Sokolovsky, K.; Bonanos, A.; Gavras, P.; Yang, M.; Hatzidimitriou, D.; Moretti, M. I.; Karampelas, A.; Bellas-Velidis, I.; Spetsieri, Z.; Pouliasis, E.; Georgantopoulos, I.; Charmandaris, V.; Tsinganos, K.; Laskaris, N.; Kakaletris, G.; Nota, A.; Lennon, D.; Arviset, C.; Whitmore, B.; Budavari, T.; Downes, R.; Lubow, S.; Rest, A.; Strolger, L.; White, R.

    2017-09-01

    We aim to construct an exceptionally deep (V ≲ 27) catalog of variable objects in selected Galactic and extragalactic fields visited multiple times by the Hubble Space Telescope (HST). While HST observations of some of these fields were searched for specific types of variables before (most notably, the extragalactic Cepheids), we attempt a systematic study of the population of variable objects of all types at the magnitude range not easily accessible with ground-based telescopes. The variability timescales that can be probed range from hours to years depending on how often a particular field has been visited. For source extraction and cross-matching of sources between visits we rely on the Hubble Source Catalog which includes 107 objects detected with WFPC2, ACS, and WFC3 HST instruments. The lightcurves extracted from the HSC are corrected for systematic effects by applying local zero-point corrections and are screened for bad measurements. For each lightcurve we compute variability indices sensitive to a broad range of variability types. The indices characterize the overall lightcurve scatter and smoothness. Candidate variables are selected as having variability index values significantly higher than expected for objects of similar brightness in the given set of observations. The Hubble Catalog of Variables will be released in 2018.

  4. The Hubble Catalog of Variables

    Directory of Open Access Journals (Sweden)

    Sokolovsky K.

    2017-01-01

    Full Text Available We aim to construct an exceptionally deep (V ≲ 27 catalog of variable objects in selected Galactic and extragalactic fields visited multiple times by the Hubble Space Telescope (HST. While HST observations of some of these fields were searched for specific types of variables before (most notably, the extragalactic Cepheids, we attempt a systematic study of the population of variable objects of all types at the magnitude range not easily accessible with ground-based telescopes. The variability timescales that can be probed range from hours to years depending on how often a particular field has been visited. For source extraction and cross-matching of sources between visits we rely on the Hubble Source Catalog which includes 107 objects detected with WFPC2, ACS, and WFC3 HST instruments. The lightcurves extracted from the HSC are corrected for systematic effects by applying local zero-point corrections and are screened for bad measurements. For each lightcurve we compute variability indices sensitive to a broad range of variability types. The indices characterize the overall lightcurve scatter and smoothness. Candidate variables are selected as having variability index values significantly higher than expected for objects of similar brightness in the given set of observations. The Hubble Catalog of Variables will be released in 2018.

  5. The Hubble-Depth Survey

    Directory of Open Access Journals (Sweden)

    Changbom Park

    2007-01-01

    Full Text Available Mediante una simulaci n de N cuerpos de un modelo ACDM hemos desarrollado una b squeda de galaxias ficticias hasta la profundidad del Hubble. Para encontrar las galaxias en la distribuci on de part culas, identificamos los halos estables y autoligados mediante un m todo de b squeda de halos en el espacio real y en el cono de luz. Suponemos que cada halo contiene solamente una galaxia con un brillo monot nicamente proporcional a la masa del halo, para as ajustar la funci n de masa con la funci n de luminosidad gal actica obtenida en el Sloan Digital Sky Survey (SDSS. Despu s de aplicar la correcciones K, y de evoluci n a las luminosidades observadas de las galaxias ficticias, hicimos estudios del corrimiento al rojo bajo varias restricciones observacionales. En particular, proponemos un nuevo estudio de corrimientos al rojo, llamado el Hubble Depth Survey, el cual est limitado hasta la magnitud r = 22 y alcanza la distancia de Hubble dH = 3000 h -1 Mpe

  6. Photometry of the Stingray Nebula (V839 Ara) from 1889 TO 2015 across the Ionization of Its Planetary Nebula

    Science.gov (United States)

    Schaefer, Bradley E.; Edwards, Zachary I.

    2015-10-01

    Up until around 1980, the Stingray was an ordinary B1 post-AGB star, but then it suddenly sprouted bright emission lines like in a planetary nebula (PN), and soon after this the Hubble Space Telescope (HST) discovered a small PN around the star, so apparently we have caught a star in the act of ionizing a PN. We report here on a well-sampled light curve from 1889 to 2015, with unique coverage of the prior century plus the entire duration of the PN formation plus three decades of its aftermath. Surprisingly, the star anticipated the 1980s ionization event by declining from B = 10.30 in 1889 to B = 10.76 in 1980. Starting in 1980, the central star faded fast, at a rate of 0.20 mag year-1, reaching B = 14.64 in 1996. This fast fading is apparently caused by the central star shrinking in size. From 1994 to 2015, the V-band light curve is almost entirely from the flux of two bright [O iii] emission lines from the unresolved nebula, and it shows a consistent decline at a rate of 0.090 mag year-1. This steady fading (also seen in the radio and infrared) has a timescale equal to that expected for ordinary recombination within the nebula, immediately after a short-duration ionizing event in the 1980s. We are providing the first direct measure of the rapidly changing luminosity of the central star on both sides of a presumed thermal pulse in 1980, with this providing a strong and critical set of constraints, and these are found to sharply disagree with theoretical models of PN evolution.

  7. PHOTOMETRY OF THE STINGRAY NEBULA (V839 ARA) FROM 1889 TO 2015 ACROSS THE IONIZATION OF ITS PLANETARY NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Bradley E.; Edwards, Zachary I. [Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803 (United States)

    2015-10-20

    Up until around 1980, the Stingray was an ordinary B1 post-AGB star, but then it suddenly sprouted bright emission lines like in a planetary nebula (PN), and soon after this the Hubble Space Telescope (HST) discovered a small PN around the star, so apparently we have caught a star in the act of ionizing a PN. We report here on a well-sampled light curve from 1889 to 2015, with unique coverage of the prior century plus the entire duration of the PN formation plus three decades of its aftermath. Surprisingly, the star anticipated the 1980s ionization event by declining from B = 10.30 in 1889 to B = 10.76 in 1980. Starting in 1980, the central star faded fast, at a rate of 0.20 mag year{sup −1}, reaching B = 14.64 in 1996. This fast fading is apparently caused by the central star shrinking in size. From 1994 to 2015, the V-band light curve is almost entirely from the flux of two bright [O iii] emission lines from the unresolved nebula, and it shows a consistent decline at a rate of 0.090 mag year{sup −1}. This steady fading (also seen in the radio and infrared) has a timescale equal to that expected for ordinary recombination within the nebula, immediately after a short-duration ionizing event in the 1980s. We are providing the first direct measure of the rapidly changing luminosity of the central star on both sides of a presumed thermal pulse in 1980, with this providing a strong and critical set of constraints, and these are found to sharply disagree with theoretical models of PN evolution.

  8. The Radial Velocity Profiles of some Proplyds in the Orion Nebula

    Directory of Open Access Journals (Sweden)

    E. de la Fuente

    2003-01-01

    Full Text Available Usamos los datos obtenidos con un interferómetro de Fabry-Perot de barrido en la parte central de la Nebulosa de Orión para estudiar los proplyds de esta región. Encontramos que la interferometría de Fabry-Perot es una técnica efectiva para detectar e identificar a los proplyds. Muchos proplyds y objetos candidatos se detectan sólo después de aplicar técnicas de procesamiento a los cubos de velocidades de Fabry-Perot. Adicionalmente, presentamos los perfiles de velocidad radial, sustraídos de la región H II, de la mayoría de los proplyds detectados (13, así como de los candidatos (3. A partir de éstos, estimamos las propiedades cinemáticas más importantes de estos objetos. Encontramos que todos los proplyds tienen velocidades corridas al rojo con respecto a la Nebulosa de Orión. Encontramos también que los proplyds que estudiamos tienen valores típicos de pérdida de masa y de escala temporal del disco y discutimos las implicaciones de esto, tomando en cuenta que nuestro estudio es sobre una buena proporción de proplyds. Finalmente, vemos que nuestros perfiles de velocidad sugieren que una buena fracción de proplyds presentan microjets monopolares.

  9. Temperature variations and n+/o+ in the orion nebula II the collision strengths

    Directory of Open Access Journals (Sweden)

    R. H. Rubin

    2001-01-01

    Full Text Available Continuamos una investigaci on de la temperatura electr onica (Te, la variaci on rms de Te, (t2, y el cociente de abundancias N+/O+. En nuestros an alisis anteriores de espectros de HST de la nebulosa de Ori on se usaron fuerzas de coli- si on para N+ calculadas por Sta ord et al.(1994. Aqu examinamos el efecto de sustituir estos valores por los de Lennon & Burke (1994. En lugar de utilizar la aproximaci on de baja densidad Ne, presentamos una t ecnica num erica que es v alida para cualquier densidad. Con las fuerzas de colisi on de Sta ord et al. encontramos que la densidad Ne promedio para la regi on (N+, O+ es 7500 cm

  10. YSOVAR: Six Pre-main-sequence Eclipsing Binaries in the Orion Nebula Cluster

    Science.gov (United States)

    2012-06-25

    includes background subtraction, cosmic -hit removal, flat-fielding, and wavelength calibration. 23 http://www2.keck.hawaii.edu/inst/nirspec-old/redspec...Inclination and combined radius are highly degenerated; inclination and temperature ratio are less so, but also provide weaker constraints. (A color version of...example, the model isochrones of Siess et al. (2000) predict a radius sum of 11.1–14.5R for ages in the range of 0.3–2 Myr. 5.2. ISOY J0535−0447 ISOY

  11. Ionized gas diagnostics from protoplanetary discs in the Orion Nebula and the abundance discrepancy problem

    CERN Document Server

    Mesa-Delgado, A; Esteban, C; García-Rojas, J; Flores-Fajardo, N; López-Martín, L; Tsamis, Y G; Henney, W J

    2012-01-01

    We present results from integral field spectroscopy with PMAS. The observed field contains: five protoplanetary discs (also known as proplyds), the high-velocity jet HH 514 and a bowshock. Spatial distribution maps are obtained for different emission line fluxes, the c(H{\\beta}) coefficient, electron densities and temperatures, ionic abundances of different ions from collisionally excited lines (CELs), C2+ and O2+ abundances from recombination lines (RLs) and the abundance discrepancy factor of O2+, ADF(O2+). We find that collisional de-excitation has a major influence on the line fluxes in the proplyds. If this is not properly accounted for then physical conditions deduced from commonly used line ratios will be in error, leading to unreliable chemical abundances for these objects. We obtain the intrinsic emission of the proplyds 177-341, 170-337 and 170-334 by a direct subtraction of the background emission, though the last two present some background contamination due to their small sizes. A detailed analys...

  12. Hα Fabry-Perot Study in the Orion Nebula (M 42: Protoplanetary Disks

    Directory of Open Access Journals (Sweden)

    Eduardo de la Fuente

    2003-01-01

    Full Text Available Se presenta un resumen de los resultados cinemáticas obtenidos del estudio Fabry-Perot en Hα de algunos proplyds en la nebulosa de Orión. Estos resultados se presentan en detalle en de la Fuente et al. (2003 a,b. Se obtienen velocidades sistémicas, tasas de perdida de masa, edad de los discos y perfiles de velocidad radial. Encontramos que la interferometria Fabry-Perot constituye una técnica efectiva para la detección de proplyds. Se discuten algunos aspectos astrobiológicos de estos resultados que ilustramos usando los proplyds 168-326, 167-317, 163-317, 158-323, 158-327 y 161-314.

  13. Discovery of powerful gamma-ray flares from the Crab Nebula.

    Science.gov (United States)

    Tavani, M; Bulgarelli, A; Vittorini, V; Pellizzoni, A; Striani, E; Caraveo, P; Weisskopf, M C; Tennant, A; Pucella, G; Trois, A; Costa, E; Evangelista, Y; Pittori, C; Verrecchia, F; Del Monte, E; Campana, R; Pilia, M; De Luca, A; Donnarumma, I; Horns, D; Ferrigno, C; Heinke, C O; Trifoglio, M; Gianotti, F; Vercellone, S; Argan, A; Barbiellini, G; Cattaneo, P W; Chen, A W; Contessi, T; D'Ammando, F; DePris, G; Di Cocco, G; Di Persio, G; Feroci, M; Ferrari, A; Galli, M; Giuliani, A; Giusti, M; Labanti, C; Lapshov, I; Lazzarotto, F; Lipari, P; Longo, F; Fuschino, F; Marisaldi, M; Mereghetti, S; Morelli, E; Moretti, E; Morselli, A; Pacciani, L; Perotti, F; Piano, G; Picozza, P; Prest, M; Rapisarda, M; Rappoldi, A; Rubini, A; Sabatini, S; Soffitta, P; Vallazza, E; Zambra, A; Zanello, D; Lucarelli, F; Santolamazza, P; Giommi, P; Salotti, L; Bignami, G F

    2011-02-11

    The well-known Crab Nebula is at the center of the SN1054 supernova remnant. It consists of a rotationally powered pulsar interacting with a surrounding nebula through a relativistic particle wind. The emissions originating from the pulsar and nebula have been considered to be essentially stable. Here, we report the detection of strong gamma-ray (100 mega-electron volts to 10 giga-electron volts) flares observed by the AGILE satellite in September 2010 and October 2007. In both cases, the total gamma-ray flux increased by a factor of three compared with the non-flaring flux. The flare luminosity and short time scale favor an origin near the pulsar, and we discuss Chandra Observatory x-ray and Hubble Space Telescope optical follow-up observations of the nebula. Our observations challenge standard models of nebular emission and require power-law acceleration by shock-driven plasma wave turbulence within an approximately 1-day time scale.

  14. Illuminating gas in-/outflows in the MUSE deepest fields: discovery of Ly-alpha nebulae around forming galaxies at z~3.3

    CERN Document Server

    Vanzella, E; Gronke, M; Karman, W; Caminha, G B; Dijkstra, M; Rosati, P; De Barros, S; Caputi, K; Grillo, C; Tozzi, P; Meneghetti, M; Mercurio, A; Gilli, R

    2016-01-01

    We report on the discovery of extended Ly-alpha nebulae at z~3.3 in the Hubble Ultra Deep Field (HUDF, ~ 40 kpc X 80 kpc) and behind the Hubble Frontier Fields galaxy cluster MACSJ0416 (~ 40kpc), spatially associated with groups of star-forming galaxies. VLT/MUSE integral field spectroscopy reveals a complex structure with a spatially-varying double peaked Ly-alpha emission. Overall, the spectral profiles of the two Ly-alpha nebulae are remarkably similar, both showing a prominent blue emission, more intense and slightly broader than the red peak. From the first nebula, located in the HUDF, no X-ray emission has been detected, disfavoring the possible presence of AGNs. Spectroscopic redshifts have been derived for 11 galaxies within two arcsec from the nebula and spanning the redshift range 1.037nebula, behind MACSJ0416, shows three aligned star-forming galaxies plausibly associated to the emitting gas. In both systems, the associated galaxies reveal possible intense rest-frame-optic...

  15. The Fe/Ni ratio in ionized nebulae: clues on dust depletion patterns

    CERN Document Server

    Delgado-Inglada, Gloria; García-Rojas, Jorge; Rodríguez, Mónica; Esteban, César

    2015-01-01

    We perform a homogeneous analysis of the Fe/Ni abundance ratio in eight Galactic planetary nebulae (PNe) and three Galactic H II regions that include the Orion nebula, where we study four nebular zones and one shocked region. We use [Fe ii], [Fe iii], and [Ni iii] lines, and ionization correction factors (ICFs) that account for the unobserved ions. We derive an ICF for nickel from an extensive grid of photoionization models. We compare our results with those derived by other authors for 16 neutral clouds in the solar neighbourhood with available Fe/Ni ratios in the literature. We find an excellent agreement between the ionized nebulae and the diffuse clouds, with both types of regions showing a clear correlation between the Fe/Ni ratios and the iron and nickel depletion factors. The trend shows that the objects with a relatively low depletion have near solar Fe/Ni ratios whereas at higher depletions the Fe/Ni ratio increases with the depletion. Our results confirm that, compared to iron atoms, nickel ones are...

  16. Stars and Nebulae in the Southern Crown

    Science.gov (United States)

    2000-10-01

    The R Coronae Australis complex of young stars and interstellar gas clouds is one of the nearest star-forming regions, at a distance of approx. 500 light-years from the Sun. It is seen in the southern constellation of that name (The "Southern Crown"). Images of this sky area were recently obtained with the Wide Field Imager (WFI) , a 67-million pixel digital camera that is installed at the 2.2-m MPG/ESO Telescope at ESO's La Silla Observatory. Some of these exposures have been combined into a magnificent colour image, here reproduced as PR Photo 25a/00 . The field shown measures about 4.7 x 4.7 light-years 2. It displays the central part of the complex, its brightest stars, and the nebulosity that they illuminate. The interstellar clouds that are associated with the complex are visible all across this field and also beyond its borders (on other exposures), due to the obscuring effect of the dust particles that "dim" the light of stars behind these clouds. This effect is particularly noticeable in the lower left corner where very few stars are seen. R Coronae Australis , the bright star from which the entire complex is named, is located at the center of the field and illuminates the reddish nebula around it. The bright star in the lower part, illuminating a somewhat bluer nebula, is known as TY Coronae Australis . The brightness of these two stars and several others in the same field is variable. They belong to the so-called "T Tauri" class , a type that is quite common in star-forming regions. T Tauri stars are in the early stages of stellar evolution and display various observable characteristics of this phase, e.g. emission at visible and infrared wavelengths due to the accretion of matter left over from their formation, as well as X-ray emission. The nebulosity seen in this picture is mostly due to reflection of the stellar light by small dust particles. The stars in the R Coronae Australis complex do not emit sufficient ultraviolet light to ionize a substantial

  17. A Starfish Preplanetary Nebula: IRAS 19024+0044

    Science.gov (United States)

    Sahai, Raghvendra; Sanchez Contreras, Carmen; Morris, Mark

    2005-01-01

    Using the Hubble Space Telescope, we have imaged the OH/IR star IRAS 19024+0044 (I19024) at 0.6, 0.8, 1.1, and 1.6 micrometers, as part of our surveys of candidate preplanetary nebulae. The images show a multipolar nebula of size approximately equal to 3.'7 2.'3, with at least six elongated lobes emanating from the center of the nebula. Two of the lobes show limb-brightened tips having point-symmetric structure with respect to the expected location of the central star. The central region shows two dark bands southwest and northeast of a central shallow maximum that may be either two inclined dusty toroidal structures or the dense parts of a single wide, inhomogeneous, toroid. Avery faint, surface brightness-limited, diffuse halo surrounds the lobes. Long-slit/echelle optical spectroscopy obtained at the Mount Palomar and Keck observatories shows a spatially compact source of H(alpha) emission; the H(alpha) line shows a strong, narrow, central core with very broad (+/-1000 km/sec), weak wings, and a narrower blueshifted absorption feature signifying the presence of an approximately 100 km/sec(exp -1) outflow. The spectrum is characterized by a strong, relatively featureless, continuum and lacks the strong forbidden emission lines characteristic of planetary nebulae, confirming that IRAS 19024 is a preplanetary nebula; the spectral type for the central star, although uncertain, is most likely early G. Interferometric observations of the CO J = 1 -0 line emission with the Owens Valley Radio Interferometer show a marginally resolved molecular envelope (size 5.'5 x 4.'4) with an expansion velocity of 13 km/sec (exp -1), resulting from the asymptotic giant branch (AGB) progenitor's dense, slow wind. We derive a kinematic distance of 3.5 kpc to I19024, based on its radial velocity. The bolometric flux is 7:3 x 10(exp -9) erg s(exp -1) cm(exp -2), and the luminosity 2850 L. The relatively low luminosity of I19024, in comparison with stellar evolutionary models, indicates

  18. Iron Abundance in Hydrogen-Rich Central Stars of Planetary Nebulae

    CERN Document Server

    Hoffmann, A I D; Kruk, J W; Rauch, T; Traulsen, I; Werner, K

    2004-01-01

    We report on an on-going analysis of high-resolution UV spectra of hot hydrogen-rich central stars of planetary nebulae (CSPN), obtained with the Hubble Space Telescope and FUSE. Since UV spectra of many CSPN are dominated by Fe and Ni lines, we intend to use them as temperature indicators to check the CSPN temperature scale we have derived earlier from CNO ionization balances. Furthermore, the observed line strengths of heavy metals show large variations between different objects suggesting a possible spread in abundances. We will determine abundances of iron group elements by quantitative spectral analyses with non-LTE model atmospheres.

  19. Application of Terrestrial Environments in Orion Assessments

    Science.gov (United States)

    Barbre, Robert E.

    2016-01-01

    This presentation summarizes the Marshall Space Flight Center Natural Environments Terrestrial and Planetary Environments (TPE) Team support to the NASA Orion space vehicle. The TPE utilizes meteorological data to assess the sensitivities of the vehicle due to the terrestrial environment. The Orion vehicle, part of the Multi-Purpose Crew Vehicle Program, is designed to carry astronauts beyond low-earth orbit and is currently undergoing a series of tests including Exploration Test Flight (EFT) - 1. The presentation describes examples of TPE support for vehicle design and several tests, as well as support for EFT-1 and planning for upcoming Exploration Missions while emphasizing the importance of accounting for the natural environment's impact to the vehicle early in the vehicle's program.

  20. Hubble Systems Optimize Hospital Schedules

    Science.gov (United States)

    2009-01-01

    Don Rosenthal, a former Ames Research Center computer scientist who helped design the Hubble Space Telescope's scheduling software, co-founded Allocade Inc. of Menlo Park, California, in 2004. Allocade's OnCue software helps hospitals reclaim unused capacity and optimize constantly changing schedules for imaging procedures. After starting to use the software, one medical center soon reported noticeable improvements in efficiency, including a 12 percent increase in procedure volume, 35 percent reduction in staff overtime, and significant reductions in backlog and technician phone time. Allocade now offers versions for outpatient and inpatient magnetic resonance imaging (MRI), ultrasound, interventional radiology, nuclear medicine, Positron Emission Tomography (PET), radiography, radiography-fluoroscopy, and mammography.

  1. Friedmann equation and Hubble condition

    CERN Document Server

    Baumgaertel, Hellmut

    2014-01-01

    The note presents results on the solutions of the Friedmann equation, which satisfy the Hubble condition, where the radiation term is taken into account. For these solutions the equation $\\sigma=\\sigma_{cr}$, where $\\sigma$ is the radiation invariant of the Friedmann equation and $\\sigma_{cr}$ the "critical radiation parameter", introduced in [5], is an analytic relation between the matter density and the radiation density at the present time and the cosmological constant which can be represented by two function branches, expressing the cosmological constant as unique functions of the matter and radiation density. These functions are the "frontier lines" between regions of constant type.

  2. ORION - A Global Approach to Waste Management.

    Science.gov (United States)

    Heinzelmann, Elsbeth

    2015-01-01

    In the ORION project supported by the European Commission, 20 partners work together to manage organic waste from agro-food industries. The goal is to develop a small, automatic and user-friendly digestion machine to facilitate the domestic on-site treatment of a wide range of organic waste from around 100 and up to 5000 tonnes per year at low cost and with limited maintenance. Simon Crelier at the HES-SO Valais/Wallis is part of the network.

  3. Lightning Protection for the Orion Space Vehicle

    Science.gov (United States)

    Scully, Robert

    2015-01-01

    The Orion space vehicle is designed to requirements for both direct attachment and indirect effects of lightning. Both sets of requirements are based on a full threat 200kA strike, in accordance with constraints and guidelines contained in SAE ARP documents applicable to both commercial and military aircraft and space vehicles. This paper describes the requirements as levied against the vehicle, as well as the means whereby the design shows full compliance.

  4. Deuterated methanol in Orion BN/KL

    CERN Document Server

    Peng, T -C; Brouillet, N; Parise, B; Baudry, A

    2012-01-01

    Deuterated molecules have been detected and studied toward Orion BN/KL in the past decades, mostly with single-dish telescopes. However, high angular resolution data are critical not only for interpreting the spatial distribution of the deuteration ratio but also for understanding this complex region in terms of cloud evolution involving star-forming activities and stellar feedbacks. We present here the first high angular resolution (1.8 arcsec \\times 0.8 arcsec) images of deuterated methanol CH2DOH in Orion BN/KL observed with the IRAM Plateau de Bure Interferometer from 1999 to 2007 in the 1 to 3 mm range. Six CH2DOH lines were detected around 105.8, 223.5, and 225.9 GHz. In addition, three E-type methanol lines around 101-102 GHz were detected and were used to derive the corresponding CH3OH rotational temperatures and column densities toward different regions across Orion BN/KL. The strongest CH2DOH and CH3OH emissions come from the Hot Core southwest region with an LSR velocity of about 8 km/s. We derive ...

  5. Veiling in Orion T Tauri Stars

    Science.gov (United States)

    Hawks, E. L.; Johns-Krull, C. M.; Hamilton, C. M.

    2005-12-01

    We use the cross dispersed echelle spectrometer on the 2.7 m Harlan J. Smith telescope at McDonald Observatory to measure the optical veiling in several classical T Tauri stars with known rotation periods in the Orion star formation region. Veiling is the excess continuum produced as circumstellar matter accretes onto the stellar surface. Pervious studies have generally ignored this excess continuum when analyzing the V, R and I colors to determine stellar and accretion properties of the low mass young stars in Orion. We find for a number of stars that the veiling flux contributes significantly to the V and Ic colors. We use our veiling measurements to correct literature photometric data in order to calculate new extinction values and intrinsic magnitudes for each star. We then use these corrected magnitudes with pre-main sequence evolutionary tracks to obtain new estimates of the stellar luminosity, radius, mass, and age of each star in our sample. Combining these updated parameters with our veiling measurements, we determine accurate accretion rate estimates which we will use to test disk locking theory in the low mass stars of Orion. This research was supported in part by a NASA Origins grant to Rice University.

  6. Molecular studies of Planetary Nebulae

    CERN Document Server

    Zhang, Yong

    2016-01-01

    Circumstellar envelopes (CEs) around evolved stars are an active site for the production of molecules. After evolving through the Asymptotic Giant Branch (AGB), proto-planetary nebula (PPN), to planetary nebula (PN) phases, CEs ultimately merge with the interstellar medium (ISM). The study of molecules in PNe, therefore, is essential to understanding the transition from stellar to interstellar materials. So far, over 20 molecular species have been discovered in PNe. The molecular composition of PNe is rather different from those of AGB and PPNe, suggesting that the molecules synthesized in PN progenitors have been heavily processed by strong ultraviolet radiation from the central star. Intriguingly, fullerenes and complex organic compounds having aromatic and aliphatic structures can be rapidly formed and largely survive during the PPN/PN evolution. The similar molecular compositions in PNe and diffuse clouds as well as the detection of C$_{60}^+$ in the ISM reinforce the view that the mass-loss from PNe can ...

  7. Modified Hubble law, the time-varying Hubble parameter and the problem of dark energy

    OpenAIRE

    Liu, Jian-Miin

    2005-01-01

    In the framework of the solvable model of cosmology constructed in the Earth-related coordinate system, we derive the modified Hubble law. This law carries the slowly time-varying Hubble parameter. The modified Hubble law eliminates the need for dark energy.

  8. Modified Hubble law, the time-varying Hubble parameter and the problem of dark energy

    OpenAIRE

    Liu, Jian-Miin

    2005-01-01

    In the framework of the solvable model of cosmology constructed in the Earth-related coordinate system, we derive the modified Hubble law. This law carries the slowly time-varying Hubble parameter. The modified Hubble law eliminates the need for dark energy.

  9. Observations of the filamentary nebula Simeiz 22

    Science.gov (United States)

    Lozinskaya, T. A.; Sitnik, T. G.; Toropova, M. S.; Klement'eva, A. Yu.

    1984-02-01

    Interference-filter photographs of the nebula Simeiz 22 (Sharpless 188) in the (S II), (N II), (O III) lines, taken with a contact image tube at the Cassegrain focus of the 125-cm Crimean reflector, have been processed by photographic equidensitometry, yielding detailed isophotes in each line. The nebula morphology differs in the three lines, showing the stratified emission typical of planetary nebulae. The origin of Simeiz 22 is discussed; indirect arguments point to mass loss by the central star.

  10. The western Veil nebula (Image)

    Science.gov (United States)

    Glenny, M.

    2009-12-01

    The western Veil nebula in Cygnus. 15-part mosaic by Mike Glenny, Gloucestershire, taken over several months mostly in the autumn of 2008. 200mm LX90/f10 autoguided, Meade UHC filter, 0.3xFR/FF, Canon 20Da DSLR. Exposures each typically 10x360 secs at ISO1600, processed in Registax4, PixInsight (for flat field correction) & Photoshop CS.

  11. Gallery of Planetary Nebula Spectra

    CERN Document Server

    Kwitter, K B; Kwitter, Karen B.; Henry, Richard B.C.

    2006-01-01

    We present the Gallery of Planetary Nebula Spectra now available at http://oitwilliams.edu/nebulae. The website offers high-quality, moderate resolution (~7-10 A FWHM) spectra of 128 Galactic planetary nebulae from 3600-9600 A, obtained by Kwitter, Henry, and colleagues with the Goldcam spectrograph at the KPNO 2.1-m or with the RC spectrograph at the CTIO 1.5-m. The master PN table contains atlas data and an image link. A selected object's spectrum is displayed in a zoomable window; line identification templates are provided. In addition to the spectra themselves, the website also contains a brief discussion of PNe as astronomical objects and as contributors to our understanding of stellar evolution. We envision that this website, which concentrates a large amount of data in one place, will be of interest to a variety of users: researchers might need to check the spectrum of a particular object of interest; the non-specialist astronomer might simply be interested in perusing such a collection of spectra; and...

  12. The Trumpler 14 photodissociation region in the Carina Nebula

    Science.gov (United States)

    Brooks, K. J.; Cox, P.; Schneider, N.; Storey, J. W. V.; Poglitsch, A.; Geis, N.; Bronfman, L.

    2003-12-01

    We report the results of observations of the fine-structure emission lines [C II] 158 μm and [O I] 63 μm using FIFI on the Kuiper Airborne Observatory (KAO) and the Long Wavelength Spectrometer (LWS) on board ISO, towards the molecular cloud associated with the stellar cluster Trumpler 14 (Tr 14) in the Carina Nebula. These data are compared with selected CO and CS transitions obtained with the SEST as well as IRAS and MSX images to produce a detailed view of the morphology and the physical conditions prevailing in the photodissociation region (PDR) at the interface between the ionized gas and the molecular dust lane. The relative intensity distribution observed for the various tracers is consistent with the stratification expected for a molecular cloud seen edge-on and exposed to a radiation field of ~ 104 G_0, which is dominated by the most massive stars of Tr 14. The grain photoelectric heating efficiency, \\epsilon, is estimated to be ~5 x 10-3 and is comparable to other galactic PDRs. The molecular gas has a complicated velocity structure with a high velocity dispersion resulting from the impact of the stellar winds arising from Tr 14. There is evidence of small-scale clumping with a very low volume filling factor. Despite the rich concentration of massive O stars in Tr 14 we find that the parameters of the PDR are much less-extreme than those of the Orion and M 17 massive star-forming regions.

  13. Hubble Unveils Colorful and Turbulent Star-Birth Region on 100,000th Orbit Milestone

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for orientation annotation In commemoration of NASA's Hubble Space Telescope completing its 100,000th orbit in its 18th year of exploration and discovery, scientists at the Space Telescope Science Institute in Baltimore, Md., have aimed Hubble totake a snapshot of a dazzling region of celestial birth and renewal. Hubble peered into a small portion of the nebula near the star cluster NGC 2074 (upper, left). The region is a firestorm of raw stellar creation, perhaps triggered by a nearby supernova explosion. It lies about 170,000 light-years away near the Tarantula nebula, one of the most active star-forming regions in our Local Group of galaxies. The three-dimensional-looking image reveals dramatic ridges and valleys of dust, serpent-head 'pillars of creation,' and gaseous filaments glowing fiercely under torrential ultraviolet radiation. The region is on the edge of a dark molecular cloud that is an incubator for the birth of new stars. The high-energy radiation blazing out from clusters of hot young stars already born in NGC 2074 is sculpting the wall of the nebula by slowly eroding it away. Another young cluster may be hidden beneath a circle of brilliant blue gas at center, bottom. In this approximately 100-light-year-wide fantasy-like landscape, dark towers of dust rise above a glowing wall of gases on the surface of the molecular cloud. The seahorse-shaped pillar at lower, right is approximately 20 light-years long, roughly four times the distance between our Sun and the nearest star, Alpha Centauri. The region is in the Large Magellanic Cloud (LMC), a satellite of our Milky Way galaxy. It is a fascinating laboratory for observing star-formation regions and their evolution. Dwarf galaxies like the LMC are considered to be the primitive building blocks of larger galaxies. This representative color image was taken on August 10, 2008, with Hubble's Wide Field Planetary Camera 2. Red shows emission

  14. Hubble Unveils Colorful and Turbulent Star-Birth Region on 100,000th Orbit Milestone

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on the image for orientation annotation In commemoration of NASA's Hubble Space Telescope completing its 100,000th orbit in its 18th year of exploration and discovery, scientists at the Space Telescope Science Institute in Baltimore, Md., have aimed Hubble totake a snapshot of a dazzling region of celestial birth and renewal. Hubble peered into a small portion of the nebula near the star cluster NGC 2074 (upper, left). The region is a firestorm of raw stellar creation, perhaps triggered by a nearby supernova explosion. It lies about 170,000 light-years away near the Tarantula nebula, one of the most active star-forming regions in our Local Group of galaxies. The three-dimensional-looking image reveals dramatic ridges and valleys of dust, serpent-head 'pillars of creation,' and gaseous filaments glowing fiercely under torrential ultraviolet radiation. The region is on the edge of a dark molecular cloud that is an incubator for the birth of new stars. The high-energy radiation blazing out from clusters of hot young stars already born in NGC 2074 is sculpting the wall of the nebula by slowly eroding it away. Another young cluster may be hidden beneath a circle of brilliant blue gas at center, bottom. In this approximately 100-light-year-wide fantasy-like landscape, dark towers of dust rise above a glowing wall of gases on the surface of the molecular cloud. The seahorse-shaped pillar at lower, right is approximately 20 light-years long, roughly four times the distance between our Sun and the nearest star, Alpha Centauri. The region is in the Large Magellanic Cloud (LMC), a satellite of our Milky Way galaxy. It is a fascinating laboratory for observing star-formation regions and their evolution. Dwarf galaxies like the LMC are considered to be the primitive building blocks of larger galaxies. This representative color image was taken on August 10, 2008, with Hubble's Wide Field Planetary Camera 2. Red shows emission

  15. The Hubble Ultra Deep Field

    CERN Document Server

    Beckwith, S V W; Koekemoer, A M; Caldwell, J A R; Ferguson, H C; Hook, R; Lucas, R A; Bergeron, L E; Corbin, M; Jogee, S; Panagia, N; Robberto, M; Royle, P; Somerville, R S; Sosey, M; Beckwith, Steven V. W.; Stiavelli, Massimo; Koekemoer, Anton M.; Caldwell, John A. R.; Ferguson, Henry C.; Hook, Richard; Lucas, Ray A.; Bergeron, Louis E.; Corbin, Michael; Jogee, Shardha; Panagia, Nino; Robberto, Massimo; Royle, Patricia; Somerville, Rachel S.; Sosey, Megan

    2006-01-01

    This paper presents the Hubble Ultra Deep Field (HUDF), a one million second exposure of an 11 square minute-of-arc region in the southern sky with the Hubble Space Telescope. The exposure time was divided among four filters, F435W (B435), F606W (V606), F775W (i775), and F850LP (z850), to give approximately uniform limiting magnitudes mAB~29 for point sources. The image contains at least 10,000 objects presented here as a catalog. Few if any galaxies at redshifts greater than ~4 resemble present day spiral or elliptical galaxies. Using the Lyman break dropout method, we find 504 B-dropouts, 204 V-dropouts, and 54 i-dropouts. Using these samples that are at different redshifts but derived from the same data, we find no evidence for a change in the characteristic luminosity of galaxies but some evidence for a decrease in their number densities between redshifts of 4 and 7. The ultraviolet luminosity density of these samples is dominated by galaxies fainter than the characteristic luminosity, and the HUDF reveal...

  16. Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. I. Observational overview and first results

    CERN Document Server

    Sabbi, E; Lennon, D J; van der Marel, R P; Aloisi, A; Boyer, M L; Cignoni, M; de Marchi, G; de Mink, S E; Evans, C J; Gallagher, J S; Gordon, K; Gouliermis, D A; Grebel, E K; Koekemoer, A M; Larsen, S S; Panagia, N; Ryon, J E; Smith, L J; Tosi, M; Zaritsky, D

    2013-01-01

    The Hubble Tarantula Treasury Project (HTTP) is an ongoing panchromatic imaging survey of stellar populations in the Tarantula Nebula in the Large Magellanic Cloud that reaches into the sub-solar mass regime (< 0.5 Mo). HTTP utilizes the capability of HST to operate the Advanced Camera for Surveys (ACS) and the Wide Field Camera 3 (WFC3) in parallel to study this remarkable region in the near-ultraviolet, optical, and near-infrared spectral regions, including narrow band H$\\alpha$ images. The combination of all these bands provides a unique multi-band view. The resulting maps of the stellar content of the Tarantula Nebula within its main body provide the basis for investigations of star formation in an environment resembling the extreme conditions found in starburst galaxies and in the early Universe. Access to detailed properties of individual stars allows us to begin to reconstruct the evolution of the stellar skeleton of the Tarantula Nebula over space and time with parcsec-scale resolution. In this fir...

  17. Hubble imaging of V1331 Cygni: Proper motion study of its circumstellar structures

    CERN Document Server

    Choudhary, Arpita; Linz, Hendrik

    2016-01-01

    The young star V1331 Cyg received previous attention because it is surrounded by an optical, arc-like reflection nebula. V1331 Cyg is commonly considered to be a candidate for an object that has undergone an FU-Ori (FUOR) the outbreak in the past. This in turn could lead to a time-varying appearance of the dusty arcs that may be revealed by multi-epoch imaging. In particular, a radial colour analysis of the dust arcs can then be attempted to check whether radial grain size distribution was modified by a previous FUOR wind. Second-epoch imaging of V1331 Cyg was obtained by us in 2009 using the Hubble Space Telescope (HST). By comparing this to archival HST data from 2000, we studied the time evolution of the circumstellar nebulae. After a point spread function subtraction using model point spread functions, we used customised routines to perform a proper motion analysis. The nebula expansion was first derived by deconvolving and correlating the two-epoch radial brightness profiles. Additional data from other f...

  18. A butterfly in the making revealing the near-infrared structure of Hubble 12

    CERN Document Server

    Hora, J L; Hora, Joseph L; Latter, William B

    1995-01-01

    We present deep narrowband near-IR images and moderate resolution spectra of the young planetary nebula Hubble 12. These data are the first to show clearly the complex structure for this important planetary nebula. Images were obtained at lambda = 2.12, 2.16, and 2.26 micron. The lambda = 2.12 micron image reveals the bipolar nature of the nebula, as well as complex structure near the central star in the equatorial region. The images show an elliptical region of emission which may indicate a ring or a cylindrical source structure. This structure is possibly related to the mechanism which is producing the bipolar flow. The spectra show the nature of several distinct components. The central object is dominated by recombination lines of H I and He I. The core is not a significant source of molecular hydrogen emission. The east position in the equatorial region is rich in lines of ultraviolet--excited fluorescent H2. A spectrum of part of the central region shows strong [Fe II] emission which might indicate the p...

  19. A Butterfly in the Making: Revealing the Near-Infrared Structure of Hubble 12

    Science.gov (United States)

    Hora, Joseph L.; Latter, William B.

    1996-01-01

    We present deep narrowband near-IR images and moderate resolution spectra of the young planetary nebula Hubble 12. These data are the first to show clearly the complex structure for this important planetary nebula. Images were obtained at lambda = 2.12, 2.16, and 2.26 micron. The lambda = 2.12 Am image reveals the bipolar nature of the nebula, as well as complex structure near the central star in the equatorial region. The images show an elliptical region of emission, which may indicate a ring or a cylindrical source structure. This structure is possibly related to the mechanism that is producing the bipolar flow. The spectra show the nature of several distinct components. The central object is dominated by recombination lines of H I and He I. The core is not a significant source of molecular hydrogen emission. The east position in the equatorial region is rich in lines of ultraviolet-excited fluorescent H2. A spectrum of part of the central region shows strong [Fe II] emission, which might indicate the presence of shocks.

  20. Hubble 2008: Science Year in Review

    Science.gov (United States)

    2009-01-01

    Hubbles remarkable mission has now spanned 18 years. During that time, it has been at the nexus of perhaps the most exciting period of discovery in the history of astronomy. Simultaneously, Hubble has offered up some of the most daunting engineering challenges to humans working in space, and success in meeting those challenges has been among NASAs greatest triumphs.

  1. The Spitzer Space Telescope Survey of the Orion A and B Molecular Clouds. II. The Spatial Distribution and Demographics of Dusty Young Stellar Objects

    Science.gov (United States)

    Megeath, S. T.; Gutermuth, R.; Muzerolle, J.; Kryukova, E.; Hora, J. L.; Allen, L. E.; Flaherty, K.; Hartmann, L.; Myers, P. C.; Pipher, J. L.; Stauffer, J.; Young, E. T.; Fazio, G. G.

    2016-01-01

    We analyze the spatial distribution of dusty young stellar objects (YSOs) identified in the Spitzer Survey of the Orion Molecular clouds, augmenting these data with Chandra X-ray observations to correct for incompleteness in dense clustered regions. We also devise a scheme to correct for spatially varying incompleteness when X-ray data are not available. The local surface densities of the YSOs range from 1 pc-2 to over 10,000 pc-2, with protostars tending to be in higher density regions. This range of densities is similar to other surveyed molecular clouds with clusters, but broader than clouds without clusters. By identifying clusters and groups as continuous regions with surface densities ≥10 pc-2, we find that 59% of the YSOs are in the largest cluster, the Orion Nebula Cluster (ONC), while 13% of the YSOs are found in a distributed population. A lower fraction of protostars in the distributed population is evidence that it is somewhat older than the groups and clusters. An examination of the structural properties of the clusters and groups shows that the peak surface densities of the clusters increase approximately linearly with the number of members. Furthermore, all clusters with more than 70 members exhibit asymmetric and/or highly elongated structures. The ONC becomes azimuthally symmetric in the inner 0.1 pc, suggesting that the cluster is only ˜2 Myr in age. We find that the star formation efficiency (SFE) of the Orion B cloud is unusually low, and that the SFEs of individual groups and clusters are an order of magnitude higher than those of the clouds. Finally, we discuss the relationship between the young low mass stars in the Orion clouds and the Orion OB 1 association, and we determine upper limits to the fraction of disks that may be affected by UV radiation from OB stars or dynamical interactions in dense, clustered regions.

  2. THE SPITZER SPACE TELESCOPE SURVEY OF THE ORION A AND B MOLECULAR CLOUDS. II. THE SPATIAL DISTRIBUTION AND DEMOGRAPHICS OF DUSTY YOUNG STELLAR OBJECTS

    Energy Technology Data Exchange (ETDEWEB)

    Megeath, S. T.; Kryukova, E. [Ritter Astrophsical Research Center, Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Gutermuth, R. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Muzerolle, J. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Hora, J. L.; Myers, P. C.; Fazio, G. G. [Harvard Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Allen, L. E. [National Optical Astronomical Observatory, Tucson, AZ 85719 (United States); Flaherty, K. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Hartmann, L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Pipher, J. L. [Department of Physics and Astronomy, University of Rochester, Rochester NY 14627 (United States); Stauffer, J. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Young, E. T., E-mail: megeath@physics.utoledo.edu [SOFIA-Universities Space Research Association, NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2016-01-15

    We analyze the spatial distribution of dusty young stellar objects (YSOs) identified in the Spitzer Survey of the Orion Molecular clouds, augmenting these data with Chandra X-ray observations to correct for incompleteness in dense clustered regions. We also devise a scheme to correct for spatially varying incompleteness when X-ray data are not available. The local surface densities of the YSOs range from 1 pc{sup −2} to over 10,000 pc{sup −2}, with protostars tending to be in higher density regions. This range of densities is similar to other surveyed molecular clouds with clusters, but broader than clouds without clusters. By identifying clusters and groups as continuous regions with surface densities ≥10 pc{sup −2}, we find that 59% of the YSOs are in the largest cluster, the Orion Nebula Cluster (ONC), while 13% of the YSOs are found in a distributed population. A lower fraction of protostars in the distributed population is evidence that it is somewhat older than the groups and clusters. An examination of the structural properties of the clusters and groups shows that the peak surface densities of the clusters increase approximately linearly with the number of members. Furthermore, all clusters with more than 70 members exhibit asymmetric and/or highly elongated structures. The ONC becomes azimuthally symmetric in the inner 0.1 pc, suggesting that the cluster is only ∼2 Myr in age. We find that the star formation efficiency (SFE) of the Orion B cloud is unusually low, and that the SFEs of individual groups and clusters are an order of magnitude higher than those of the clouds. Finally, we discuss the relationship between the young low mass stars in the Orion clouds and the Orion OB 1 association, and we determine upper limits to the fraction of disks that may be affected by UV radiation from OB stars or dynamical interactions in dense, clustered regions.

  3. A Detailed Study of the Structure of the Nested Planetary Nebula, Hb 12, the Matryoshka Nebula

    Science.gov (United States)

    Clark, D. M.; López, J. A.; Edwards, M. L.; Winge, C.

    2014-11-01

    We present near-IR, integral field spectroscopic observations of the planetary nebula (PN) Hb 12 using Near-infrared Integral Field Spectrograph (NIFS) on Gemini-North. Combining NIFS with the adaptive optics system Altair, we provide a detailed study of the core and inner structure of this PN. We focus the analysis in the prominent emission lines [Fe II] (1.6436 μm), He I (2.0585 μm), H2 (2.1214 μm), and Brγ (2.16553 μm). We find that the [Fe II] emission traces a tilted system of bipolar lobes, with the northern lobe being redshifted and the southern lobe blueshifted. The [Fe II] emission is very faint at the core and only present close to the systemic velocity. There is no H2 emission in the core, whereas the core is prominent in the He I and Brγ recombination lines. The H2 emission is concentrated in equatorial arcs of emission surrounding the core and expanding at ~30 km s-1. These arcs are compared with Hubble Space Telescope images and shown to represent nested loops belonging to the inner sections of a much larger bipolar structure that replicates the inner one. The He I and Brγ emission from the core clearly show a cylindrical central cavity that seems to represent the inner walls of an equatorial density enhancement or torus. The torus is 0.''2 wide (≡200 AU radius at a distance of 2000 pc) and expanding at <=30 km s-1. The eastern wall of the inner torus is consistently more intense than the western wall, which could indicate the presence of an off-center star, such as is observed in the similar hourglass PN, MyCn 18. A bipolar outflow is also detected in Brγ emerging within 0.''1 from the core at ~ ± 40 km s-1.

  4. The Orion OB1 association; 2, the Orion-Eridanus bubble

    CERN Document Server

    Brown, A G A; Burton, W B; Brown, Anthony G A; Hartmann, D; Burton, W B

    1995-01-01

    Observations of the interstellar medium in the vicinity of the Orion OB1 association show a cavity filled with hot ionized gas, surrounded by an expanding shell of neutral hydrogen (the Orion-Eridanus Bubble). In this paper we examine this cavity and the surrounding bubble with the aid of data from the Leiden/Dwingeloo HI survey. We present neutral-hydrogen maps for the Orion-Eridanus region which allow identification of the HI filaments and arcs delineating the Bubble and derivation of its expansion velocity. The HI data are compared to X-ray, CO and IRAS 100 micron data. Using models of wind blown bubbles that take the density stratification of the Galactic HI layer into account we show that the stellar winds and supernovae from stars in Orion OB1 can account for the size as well as the expansion velocity of the HI shell. However, density inhomogeneities in the ambient interstellar medium cause significant discrepancies between our model and the observed shell.

  5. COSMOS Hubble Space Telescope Observations

    CERN Document Server

    Scoville, N Z; Blain, A W; Calzetti, D; Comastri, A; Capak, P; Carilli, C; Carlstrom, J E; Carollo, C M; Colbert, J; Daddi, E; Ellis, Richard S; Elvis, M; Ewald, S P; Fall, M; Franceschini, A; Giavalisco, M; Green, W; Griffiths, R E; Guzzo, L; Hasinger, G; Impey, C; Kneib, J P; Koda, J; Koekemoer, A; Lefèvre, O; Lilly, S; Liu, C T; McCracken, H J; Massey, R; Mellier, Y; Miyazaki, S; Mobasher, B; Mould, J; Norman, C; Réfrégier, A; Renzini, A; Rhodes, J; Rich, M; Sanders, D B; Schiminovich, D; Schinnerer, E; Scodeggio, M; Sheth, K; Shopbell, P L; Taniguchi, Y; Tyson, N; Urry, C M; Van Waerbeke, L; Vettolani, P; White, S D M; Yan, L

    2006-01-01

    The Cosmic Evolution Survey (COSMOS) was initiated with an extensive allocation (590 orbits in Cycles 12-13) using the Hubble Space Telescope (HST) for high resolution imaging. Here we review the characteristics of the HST imaging with the Advanced Camera for Surveys (ACS) and parallel observations with NICMOS and WFPC2. A square field (1.8$\\sq$\\deg) has been imaged with single-orbit ACS I-F814W exposures with 50% completeness for sources 0.5\\arcsec in diameter at I$_{AB} $ = 26.0 mag. The ACS imaging is a key part of the COSMOS survey, providing very high sensitivity and high resolution (0.09\\arcsec FWHM, 0.05\\arcsec pixels) imaging and detecting a million objects. These images yield resolved morphologies for several hundred thousand galaxies. The small HST PSF also provides greatly enhanced sensitivity for weak lensing investigations of the dark matter distribution.

  6. The Hubble Sphere Hydrogen Survey

    CERN Document Server

    Peterson, J B; Pen, U L; Peterson, Jeffrey B.; Bandura, Kevin; Pen, Ue Li

    2006-01-01

    An all sky redshift survey, using hydrogen 21 cm emission to locate galaxies, can be used to track the wavelength of baryon acoustic oscillations imprints from z ~ 1.5 to z = 0. This will allow precise determination of the evolution of dark energy. A telescope made of fixed parabolic cylindrical reflectors offers substantial benefit for such a redshift survey. Fixed cylinders can be built for low cost, and long cylinders also allow low cost fast fourier transform techniques to be used to define thousands of simultaneous beams. A survey made with fixed reflectors naturally covers all of the sky available from it's site with good uniformity, minimizing sample variance in the measurement of the acoustic peak wavelength. Such a survey will produce about a billion redshifts, nearly a thousand times the number available today. The survey will provide a three dimensional mapping of a substantial fraction of the Hubble Sphere.

  7. Interferometric Astrometry with Hubble Space Telescope - A Review

    Science.gov (United States)

    Benedict, G. F.; McArthur, B. E.; Franz, O. G.; Wasserman, L. H.; Henry, T. J.; Takato, T.; Strateva, I.

    2000-05-01

    We review recent results from fringe tracking (POS) and fringe scanning (TRANS) mode astrometry using Fine Guidance Sensor 3 aboard Hubble Space Telescope. The relatively large field of regard, faint limiting magnitude, and raw resolution of FGS 3 have allowed us to obtain sub-millisecond of arc precision parallaxes for several Cataclysmic Variables ( RW Tri & TV Col), a fundamental distance scale calibrator (RR Lyr), a Planetary Nebula central star (NGC 6853), and a hot White Dwarf binary (Feige 24). We have determined parallaxes, orbital parameters, and masses for low-mass binaries critical to the lower main sequence Mass-Luminosity Relationship (Gl 791.2, Wolf 1062, Gl 623). The Astrometry Science Team presently consists of W. H. Jefferys, P.I., G. F. Benedict, Deputy P.I., B. McArthur, O.G. Franz, L. H. Wasserman, L. W. Fredrick, W. van Altena, E. Nelan, R. Duncombe, P. J. Shelus, and P. D. Hemenway. This research had the support of NASA Grants NAS5-1603 (GSFC), and GO-06036.01-94A, GO-07491.01-97A (STScI).

  8. In the Shadow of Pennhurst: The Orion Community.

    Science.gov (United States)

    Lutfiyya, Zana Marie

    This case study is based on a 1988 site visit to the Orion Community, in which a group of nondisabled and disabled people have chosen to live and work with each other in Chester County, Pennsylvania. Orion's founding is described, beginning with an informal support group of professionals, parents, advocates, and members of Camphill (agricultural…

  9. Occupant Protection Project for the Orion Crew Vehicle

    Science.gov (United States)

    Gernhardt, Michael L.; Jones, Jeff

    2009-01-01

    This powerpoint presentation describes the occupant protection project for the Orion Crew Vehicle. Background information on the Orion Crew Vehicle along with comparisons of the Space Shuttle, Ares I, Ares V, Saturn V and Soyuz-FG are also described. The contents include: 1) Background and Overview; 2) Crew health and safety overview; 3) Occupant Protection project overview; and 4) Suit Element injury risk.

  10. Hubble Space Telescope-Illustration

    Science.gov (United States)

    1989-01-01

    This illustration depicts a side view of the Hubble Space Telescope (HST). The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is approximately the size of a railroad car, with two cylinders joined together and wrapped in a silvery reflective heat shield blanket. Wing-like solar arrays extend horizontally from each side of these cylinders, and dish-shaped anternas extend above and below the body of the telescope. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

  11. Planetary nebulae abundances and stellar evolution

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.

    2006-01-01

    A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are the same as HII regions and early type star abundance gradi

  12. Using Planetary Nebulae to Teach Physics

    Science.gov (United States)

    Kwitter, Karen B.

    2011-05-01

    We have developed an interactive website, "Gallery of Planetary Nebula Spectra," (www.williams.edu/Astronomy/research/PN/nebulae/) that contains high-quality optical-to-near-infrared spectra, atlas information, and bibliographic references for more than 160 planetary nebulae that we have observed in the Milky Way Galaxy. To make the material more accessible to students, I have created three undergraduate-level exercises that explore physics-related aspects of planetary nebulae. "Emission Lines and Central Star Temperature” uses the presence or absence of emission lines from species with different ionization potentials to rank the temperatures of the exciting stars in a selection of nebulae. "Interstellar Reddening” uses the observed Balmer decrement in a sample of planetary nebulae at different Galactic latitudes to infer the distribution of interstellar dust in the Milky Way. Finally, "Determining the Gas Density in Planetary Nebulae,” which I will focus on here, uses the observed intensity ratio of the 6717 Å and 6731 Å emission lines from singly ionized sulfur to determine the electron density in the nebular gas. These exercises demonstrate that planetary nebula spectra are useful real-world examples illustrating a variety of physical principles, including the behavior of blackbodies, wavelength-dependent particle scattering, recombination-line ratios, atomic physics, and statistical mechanics.

  13. Planetary nebulae abundances and stellar evolution II

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.

    2010-01-01

    Context. In recent years mid-and far infrared spectra of planetary nebulae have been analysed and lead to more accurate abundances. It may be expected that these better abundances lead to a better understanding of the evolution of these objects. Aims. The observed abundances in planetary nebulae are

  14. A GRAND VIEW OF THE BIRTH OF 'HEFTY' STARS - 30 DORADUS NEBULA MONTAGE

    Science.gov (United States)

    2002-01-01

    This picture, taken in visible light with the Hubble Space Telescope's Wide Field and Planetary Camera 2 (WFPC2), represents a sweeping view of the 30 Doradus Nebula. But Hubble's infrared camera - the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) - has probed deeper into smaller regions of this nebula to unveil the stormy birth of massive stars. The montages of images in the upper left and upper right represent this deeper view. Each square in the montages is 15.5 light-years (19 arcseconds) across. The brilliant cluster R136, containing dozens of very massive stars, is at the center of this image. The infrared and visible-light views reveal several dust pillars that point toward R136, some with bright stars at their tips. One of them, at left in the visible-light image, resembles a fist with an extended index finger pointing directly at R136. The energetic radiation and high-speed material emitted by the massive stars in R136 are responsible for shaping the pillars and causing the heads of some of them to collapse, forming new stars. The infrared montage at upper left is enlarged in an accompanying image. Credits for NICMOS montages: NASA/Nolan Walborn (Space Telescope Science Institute, Baltimore, Md.) and Rodolfo Barba' (La Plata Observatory, La Plata, Argentina) Credits for WFPC2 image: NASA/John Trauger (Jet Propulsion Laboratory, Pasadena, Calif.) and James Westphal (California Institute of Technology, Pasadena, Calif.)

  15. Hubble Tarantula Treasury Project V. The Star Cluster Hodge 301: The Old Face of 30 Doradus

    Science.gov (United States)

    Cignoni, M.; Sabbi, E.; van der Marel, R. P.; Lennon, D. J.; Tosi, M.; Grebel, E. K.; Gallagher, J. S., III; Aloisi, A.; de Marchi, G.; Gouliermis, D. A.; Larsen, S.; Panagia, N.; Smith, L. J.

    2016-12-01

    Based on color-magnitude diagrams (CMDs) from the Hubble Space Telescope Hubble Tarantula Treasury Project (HTTP) survey, we present the star formation history of Hodge 301, the oldest star cluster in the Tarantula Nebula. The HTTP photometry extends faint enough to reach, for the first time, the cluster pre-main sequence (PMS) turn-on, where the PMS joins the main sequence. Using the location of this feature, along with synthetic CMDs generated with the latest PARSEC models, we find that Hodge 301 is older than previously thought, with an age between 26.5 and 31.5 Myr. From this age, we also estimate that between 38 and 61 Type II supernovae exploded in the region. The same age is derived from the main sequence turn-off, whereas the age derived from the post-main sequence stars is younger and between 20 and 25 Myr. Other relevant parameters are a total stellar mass of ≈8800 ± 800 M ⊙ and average reddening E(B - V) ≈ 0.22-0.24 mag, with a differential reddening δE(B - V) ≈ 0.04 mag. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA Inc., under NASA contract NAS 5-26555.

  16. Orion FSW V and V and Kedalion Engineering Lab Insight

    Science.gov (United States)

    Mangieri, Mark L.

    2010-01-01

    NASA, along with its prime Orion contractor and its subcontractor s are adapting an avionics system paradigm borrowed from the manned commercial aircraft industry for use in manned space flight systems. Integrated Modular Avionics (IMA) techniques have been proven as a robust avionics solution for manned commercial aircraft (B737/777/787, MD 10/90). This presentation will outline current approaches to adapt IMA, along with its heritage FSW V&V paradigms, into NASA's manned space flight program for Orion. NASA's Kedalion engineering analysis lab is on the forefront of validating many of these contemporary IMA based techniques. Kedalion has already validated many of the proposed Orion FSW V&V paradigms using Orion's precursory Flight Test Article (FTA) Pad Abort 1 (PA-1) program. The Kedalion lab will evolve its architectures, tools, and techniques in parallel with the evolving Orion program.

  17. Orion Ammonia Boiler System Preflight Test Preparations

    Science.gov (United States)

    Levitt, Julia L.

    2017-01-01

    The Environmental Controls and Life Support Systems (ECLSS) branch at Kennedy Space Center (KSC) is currently undergoing preparations for ground testing of the Orion Multi-Purpose Crew Vehicle (MPCV) to prepare its subsystems for EM-1 (Exploration Mission-1). EM-1, Orions second unmanned flight, is a three-week long lunar mission during which the vehicle will complete a 6-day retrograde lunar orbit before returning to Earth. This paper focuses on the work done during the authors 16-week internship with the Mechanical Engineering Branch of KSCs Engineering Directorate. The authors project involved assisting with the preparations for testing the Orion MPCVs ammonia boiler system. The purpose of the ammonia boiler system is to keep the spacecraft sufficiently cool during the reentry portion of its mission, from service module (SM) separation to post-landing. This system is critical for keeping both the spacecraft (avionics and electronics) and crew alive during reentry, thus a successful test of the system is essential to the success of EM-1. XXXX The author was able to draft a detailed outline of the procedure for the ammonia system functional test. More work will need to be done on the vehicle power-up and power-down portions of the procedure, but the ammonia system testing portion of the procedure is thorough and includes vehicle test configurations, vehicle commands, and GSE. The author was able to compile a substantial list of questions regarding the ammonia system functional test with the help of her mentors. A significant number of these questions were answered in the teleconferences with Lockheed Martin.

  18. A Smoking Gun in the Carina Nebula

    Science.gov (United States)

    Hamaguchi, Kenji; Corcoran, Michael F.; Ezoe, Yuichiro; Townsley, Leisa; Broos, Patrick; Gruendl, Robert; Vaidya, Kaushar; White, Stephen M.; Petre, Rob; Chu, You-Hua

    2009-01-01

    The Carina Nebula is one of thc youngest, most active sites of massive star formation in our Galaxy. In this nebula, we have discovered a bright X-ray source that has persisted for approx.30 years. The soft X-ray spectrum. consistent with kT approx.130 eV blackbody radiation with mild extinction, and no counterpart in the near- and mid-infrared wavelengths indicate that it is a, approx. 10(exp 6)-year-old neutron star housed in the Carina Nebula. Current star formation theory does not suggest that the progenitor of the neutron star and massive stars in the Carina Nebula, in particular (eta)Car, are coeval. This result demonstrates that the Carina Nebula experienced at least two major episodes of massive star formation. The neutron star would be responsible for remnants of high energy activity seen in multiple wavelengths.

  19. Near-Infrared Circular Polarimetry and Correlation Diagrams in the Orion BN/KL Region: Contribution of Dichroic Extinction

    CERN Document Server

    Fukue, T; Kandori, R; Kusakabe, N; Hough, J H; Lucas, P W; Bailey, J; Whittet, D C B; Nakajima, Y; Hashimoto, J; Nagata, T

    2009-01-01

    We present a deep circular polarization image of the Orion BN/KL nebula in the Ks band and correlations of circular polarization, linear polarization, and H-Ks color representing extinction. The image of circular polarization clearly reveals the quadrupolar structure around the massive star IRc2, rather than BN. H-Ks color is well correlated with circular polarization. A simple relation between dichroic extinction, color excess, circular and linear polarization is derived. The observed correlation between the Stokes parameters and the color excess agrees with the derived relation, and suggests a major contribution of dichroic extinction to the production of circular polarization in this region, indicating the wide existence of aligned grains.

  20. First Science Observations with SOFIA/FORCAST: 6 TO 37 micron Imaging of Orion BN/KL

    CERN Document Server

    De Buizer, James M; Becklin, E E; Zinnecker, Hans; Herter, Terry L; Adams, Joseph D; Shuping, Ralph Y; Vacca, William D

    2012-01-01

    The BN/KL region of the Orion Nebula is the nearest region of high mass star formation in our galaxy. As such, it has been the subject of intense investigation at a variety of wavelengths, which have revealed it to be brightest in the infrared to sub-mm wavelength regime. Using the newly commissioned SOFIA airborne telescope and its 5-40 micron camera FORCAST, images of the entire BN/KL complex have been acquired. The 31.5 and 37.1 micron images represent the highest resolution observations (31.5 microns, and that this distinction goes instead to the source IRc4. It was determined from these images and derived dust color temperature maps that IRc4 is also likely to be self-luminous. A new source of emission has also been identified at wavelengths >31.5 microns that coincides with the northeastern outflow lobe from the protostellar disk associated with radio source I.

  1. Magnetic Fields in Star-Forming Molecular Clouds IV. Polarimetry of the Filamentary NGC 2068 Cloud in Orion B

    CERN Document Server

    Matthews, B C

    2002-01-01

    We present submillimeter polarimetry at 850 micron toward the filamentary star-forming region associated with the reflection nebulosity NGC 2068 in Orion B. These data were obtained using the James Clerk Maxwell Telescope's SCUBA polarimeter. The polarization pattern observed is not consistent with that expected for a field geometry defined by a single mean field direction. There are three distinct distributions of polarization angle, which could represent regions of differing inclination and/or field geometry within the filamentary gas. In general, the polarization pattern does not correlate with the underlying total dust emission. The presence of varying inclinations against the plane of the sky is consistent with the comparison of the 850 micron continuum emission to the optical emission from the Palomar Optical Sky Survey, which shows that the western dust emission lies in the foreground of the optical nebula while the eastern dust emission originates in the background. Percentage polarizations are high, ...

  2. Thermochemical Ablation Analysis of the Orion Heatshield

    Science.gov (United States)

    Sixel, William

    2015-01-01

    The Orion Multi-Purpose Crew Vehicle will one day carry astronauts to the Moon and beyond, and Orion's heatshield is a critical component in ensuring their safe return to Earth. The Orion heatshield is the structural component responsible for absorbing the intense heating environment caused by re-entry to Earth's atmosphere. The heatshield is primarily composed of Avcoat, an ablative material that is consumed during the re-entry process. Ablation is primarily characterized by two processes: pyrolysis and recession. The decomposition of in-depth virgin material is known as pyrolysis. Recession occurs when the exposed surface of the heatshield reacts with the surrounding flow. The Orion heatshield design was changed from an individually filled Avcoat honeycomb to a molded block Avcoat design. The molded block Avcoat heatshield relies on an adhesive bond to keep it attached to the capsule. In some locations on the heatshield, the integrity of the adhesive bond cannot be verified. For these locations, a mechanical retention device was proposed. Avcoat ablation was modelled in CHAR and the in-depth virgin material temperatures were used in a Thermal Desktop model of the mechanical retention device. The retention device was analyzed and shown to cause a large increase in the maximum bondline temperature. In order to study the impact of individual ablation modelling parameters on the heatshield sizing process, a Monte Carlo simulation of the sizing process was proposed. The simulation will give the sensitivity of the ablation model to each of its input parameters. As part of the Monte Carlo simulation, statistical uncertainties on material properties were required for Avcoat. Several properties were difficult to acquire uncertainties for: the pyrolysis gas enthalpy, non-dimensional mass loss rate (B´c), and Arrhenius equation parameters. Variability in the elemental composition of Avcoat was used as the basis for determining the statistical uncertainty in pyrolysis gas

  3. Assessment of Fencing on the Orion Heatshield

    Science.gov (United States)

    Alunni, Antonella I.; Gokcen, Tahir

    2016-01-01

    This paper presents recession measurements of arc-jet test articles that simulate an ablator with gap filler and were exposed to various heating profiles. Results were used to derive empirically-based differential recession models used for the baseline sizing of the Orion block heatshield architecture. The profile test conditions represent different local flight environments associated with different regions of the heatshield. Recession measurements were collected during and after arc-jet tests, and the results were used to observe the heating profiles’ effect on differential recession. Arc-jet tests were conducted at the Aerodynamic Heating Facility at NASA Ames Research Center.

  4. Gray Extinction in the Orion Trapezium

    Science.gov (United States)

    Krełowski, J.; Galazutdinov, G. A.; Strobel, A.; Mulas, G.

    2016-12-01

    We estimated distances to several Orion Trapezium stars using our CaII-method and confirm the distance recommended by Menten et al. However, we found that in the case of HD 37020 both individual distances (based on the trigonometric VLBI parallax and/or CaII-method) differ from the spectrophotometric distance by a factor of 2.5. We interpret this fact as a result of presence of gray (neutral) extinction of about 1.8 mag in front of this star. The correctness of the applied spectral type/ luminosity class, Sp/L, (based on new original spectra from HARPS-N) and measurements of color indices is discussed.

  5. Central Stars of Planetary Nebulae

    CERN Document Server

    Jones, David

    2016-01-01

    In this brief invited review, I will attempt to summarise some of the key areas of interest in the study of central stars of planetary nebulae which (probably) won't be covered by other speakers' proceedings. The main focus will, inevitably, be on the subject of multiplicity, with special emphasis on recent results regarding triple central star systems as well as wide binaries which avoid a common-envelope phase. Furthermore, in light of the upcoming release of Kepler's Campaign 11 data, I will discuss a few of the prospects from that data including the unique possibility to detect merger products.

  6. The APEX-CHAMP+ view of the Orion Molecular Cloud 1 core - Constraining the excitation with submillimeter CO multi-line observations

    CERN Document Server

    Peng, T -C; Zapata, L A; Güsten, R; Menten, K M

    2011-01-01

    A high density portion of the Orion Molecular Cloud 1 (OMC-1) contains the prominent, warm Kleinmann-Low (KL) nebula that is internally powered by an energetic event plus a farther region in which intermediate to high mass stars are forming. Its outside is affected by ultraviolet radiation from the neighboring Orion Nebula Cluster and forms the archetypical photon-dominated region (PDR) with the prominent bar feature. Its nearness makes the OMC-1 core region a touchstone for research on the dense molecular interstellar medium and PDRs. Using the Atacama Pathfinder Experiment telescope (APEX), we have imaged the line emission from the multiple transitions of several carbon monoxide (CO) isotopologues over the OMC-1 core region. Our observations employed the 2x7 pixel submillimeter CHAMP+ array to produce maps (~ 300 arcsec x 350 arcsec) of 12CO, 13CO, and C18O from mid-J transitions (J=6-5 to 8-7). We also obtained the 13CO and C18O J=3-2 images toward this region. The 12CO line emission shows a well-defined s...

  7. Hubble Gallery of Jupiter's Galilean Satellites

    Science.gov (United States)

    1995-01-01

    This is a Hubble Space Telescope 'family portrait' of the four largest moons of Jupiter, first observed by the Italian scientist Galileo Galilei nearly four centuries ago. Located approximately one-half billion miles away, the moons are so small that, in visible light, they appear as fuzzy disks in the largest ground-based telescopes. Hubble can resolve surface details seen previously only by the Voyager spacecraft in the early 1980s. While the Voyagers provided close-up snapshots of the satellites, Hubble can now follow changes on the moons and reveal other characteristics at ultraviolet and near-infrared wavelengths.Over the past year Hubble has charted new volcanic activity on Io's active surface, found a faint oxygen atmosphere on the moon Europa, and identified ozone on the surface of Ganymede. Hubble ultraviolet observations of Callisto show the presence of fresh ice on the surface that may indicate impacts from micrometeorites and charged particles from Jupiter's magnetosphere.Hubble observations will play a complementary role when the Galileo spacecraft arrives at Jupiter in December of this year.This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  8. The Spitzer Space Telescope Survey of the Orion A & B Molecular Clouds - Part I: A Census of Dusty Young Stellar Objects and a Study of their Mid-IR Variability

    CERN Document Server

    Megeath, S T; Muzerolle, J; Kryukova, E; Flaherty, K; Hora, J; Allen, L E; Hartmann, L; Myers, P C; Pipher, J L; Stauffer, J; Young, E T; Fazio, G G

    2012-01-01

    We present a survey of the Orion A and B molecular clouds undertaken with the IRAC and MIPS instruments onboard Spitzer. In total, five distinct fields were mapped covering 14 sq. degrees in five mid-IR bands spanning 3-24 microns. The survey includes the Orion Nebula Cluster, the Lynds 1641, 1630 and 1622 dark clouds, and the NGC 2023, 2024, 2068 and 2071 nebulae. These data are merged with the 2MASS point source catalog to generate a catalog of eight band photometry. We identify 3479 dusty young stellar objects (YSOs) in the Orion molecular clouds by searching for point sources with mid-IR colors indicative of reprocessed light from dusty disks or infalling envelopes. The YSOs are subsequently classified on the basis of their mid-IR colors and their spatial distributions are presented. We classify 2991 of the YSOs as pre-main sequence stars with disks and 488 as likely protostars. Most of the sources were observed with IRAC in 2-3 epochs over 6 months; we search for variability between the epochs by looking...

  9. Where Do Messy Planetary Nebulae Come From?

    Science.gov (United States)

    Kohler, Susanna

    2017-03-01

    If you examined images of planetary nebulae, you would find that many of them have an appearance that is too messy to be accounted for in the standard model of how planetary nebulae form. So what causes these structures?Examples of planetary nebulae that have a low probability of having beenshaped by a triple stellar system. They are mostly symmetric, with only slight departures (labeled) that can be explained by instabilities, interactions with the interstellar medium, etc. [Bear and Soker 2017]A Range of LooksAt the end of a stars lifetime, in the red-giant phase, strong stellar winds can expel the outer layers of the star. The hot, luminous core then radiates in ultraviolet, ionizing the gas of the ejected stellar layers and causing them to shine as a brightly colored planetary nebula for a few tens of thousands of years.Planetary nebulae come in a wide variety of morphologies. Some are approximately spherical, but others can be elliptical, bipolar, quadrupolar, or even more complex.Its been suggested that non-spherical planetary nebulae might be shaped by the presence of a second star in a binary system with the source of the nebula but even this scenario should still produce a structure with axial or mirror symmetry.A pair of scientists from Technion Israel Institute of Technology, Ealeal Bear and Noam Soker, argue that planetary nebulae with especially messy morphologies those without clear axial or point symmetries may have been shaped by an interacting triple stellar system instead.Examples of planetary nebulae that might have been shaped by a triple stellar system. They have some deviations from symmetry but also show signs of interacting with the interstellar medium. [Bear and Soker 2017]Departures from SymmetryTo examine this possibility more closely, Bear and Soker look at a sample of thousands planetary nebulae and qualitatively classify each of them into one of four categories, based on the degree to which they show signs of having been shaped by a

  10. Illuminating gas inflows/outflows in the MUSE deepest fields: Lyα nebulae around forming galaxies at z ≃ 3.3

    Science.gov (United States)

    Vanzella, E.; Balestra, I.; Gronke, M.; Karman, W.; Caminha, G. B.; Dijkstra, M.; Rosati, P.; De Barros, S.; Caputi, K.; Grillo, C.; Tozzi, P.; Meneghetti, M.; Mercurio, A.; Gilli, R.

    2017-03-01

    We report the identification of extended Lyα nebulae at z ≃ 3.3 in the Hubble Ultra Deep Field (HUDF, ≃40 kpc × 80 kpc) and behind the Hubble Frontier Field galaxy cluster MACSJ0416 (≃40 kpc), spatially associated with groups of star-forming galaxies. VLT/MUSE integral field spectroscopy reveals a complex structure with a spatially varying double-peaked Lyα emission. Overall, the spectral profiles of the two Lyα nebulae are remarkably similar, both showing a prominent blue emission, more intense and slightly broader than the red peak. From the first nebula, located in the HUDF, no X-ray emission has been detected, disfavouring the possible presence of active galactic nuclei. Spectroscopic redshifts have been derived for 11 galaxies within 2 arcsec from the nebula and spanning the redshift range 1.037 masses per year. A possible scenario is that of a group of young, star-forming galaxies emitting ionizing radiation that induces Lyα fluorescence, therefore revealing the kinematics of the surrounding gas. Also Lyα powered by star formation and/or cooling radiation may resemble the double-peaked spectral properties and the morphology observed here. If the intense blue emission is associated with inflowing gas, then we may be witnessing an early phase of galaxy or a proto-cluster (or group) formation.

  11. 75 FR 67770 - General Motors Company, Formerly Known as General Motors Corporation, Orion Assembly Plant...

    Science.gov (United States)

    2010-11-03

    ..., Orion Assembly Plant, Including On-Site Leased Workers From Aerotek Automotive, Ryder and Premier Manufacturing Support Services, Lake Orion, MI; Amended Certification Regarding Eligibility To Apply for Worker... Motors Corporation, Orion Assembly Plant, Lake Orion, Michigan. The notice was published in the...

  12. 75 FR 54388 - General Motors Company Formerly Known as General Motors Corporation, Orion Assembly Plant...

    Science.gov (United States)

    2010-09-07

    ..., Orion Assembly Plant Including On-Site Leased Workers From Aerotek Automotive Lake Orion, MI; Amended... of General Motors Company, formerly known as General Motors Corporation, Orion Assembly Plant, Lake Orion, Michigan. The notice was published in the Federal Register on April 23, 2010 (75 FR 21355)....

  13. Hubble expansion is not a velocity

    Science.gov (United States)

    Ma, Yin-Zhe; Zhang, Shuang-Nan

    2016-11-01

    In this paper, we clarify the difference between the Hubble expansion and the Doppler shift pedagogically and illustrate both physically and mathematically why the Hubble expansion cannot be regarded as a velocity. Therefore, we suggest to replace the misleading word ‘recession velocity’ to be ‘Hubble recession’ to describe the cosmic expansion. We further derive how the peculiar velocity of a galaxy is related to its observed redshift and proper distance, which has practical use in the galaxy redshift and distance surveys.

  14. Fermi LAT Observations of the Crab Nebula During the Exceptional April 2011 Outburst

    Science.gov (United States)

    Hays, Elizabeth

    2012-01-01

    The Crab Nebula, formerly thought to be steady in gamma rays, shows unexpected and occasionally dramatic variability in high-energy gamma rays. The Large Area Telescope (LAT) on Fermi recorded several strong outbursts, including dedicated pointed observations of the brightest yet seen, a spectacular flare in April 2011. These observations provide a particularly detailed look at the temporal and spectral characteristics of the nebula during the flare. The LAT data show an additional component in the spectral energy distribution that peaks at a maximum of $375\\pm26\\mathrm{MeV}$. In the probable scenario that this component is synchrotron emission, the electrons are accelerated to extreme energies that are difficult to reconcile with the very rapid change in flux and the expectation for acceleration processes and conditions occurring within the pulsar wind nebula. The physical location and mechanism driving the flares remains undetermined despite observations across the spectrum made by a variety of instruments including the Hubble Space Telescope, the Chandra X-ray Observatory, and the Very Large Array. I will present timing and spectral studies of the high-energy gamma-ray data, discuss implications for the origin of the flares, and highlight preparations for the next major flare.

  15. Science on NIF Eagle Nebula

    Science.gov (United States)

    Kane, Jave; Martinez, David; Pound, Marc; Heeter, Robert; Casner, Alexis; Villette, Bruno; Mancini, Roberto

    2014-10-01

    For over fifteen years astronomers at the University of Maryland and scientists at LLNL have investigated the origin and dynamics of the famous Pillars of the Eagle Nebula and similar parsec-scale structures at the boundaries of HII regions in molecular hydrogen clouds. Eagle Nebula is one of the National Ignition Facility (NIF) Science programs, and has been awarded two days of NIF shots to study the cometary model of pillar formation. The NIF shots will feature a new long-duration x-ray source prototyped at the Omega EP laser, in which multiple hohlraums mimicking a cluster of stars are driven with UV light in series for 10 ns each to create a 30 ns output x-ray pulse. The drive generates deeply nonlinear hydrodynamics in the Eagle science package, which consists of a dense layered plastic and foam core embedded in lower-density background foam. The scaled Omega EP shots validated the multi-hohlraum concept, showing that earlier time hohlraums do not degrade later time hohlraums by preheat or by ejecting ablated plumes that deflect the later beams. The Omega EP shots illuminated three 2.8 mm long by 1.4 mm diameter Cu hohlraums with 4.3 kJ per hohlraum. At NIF each hohlraum will be 4 mm long by 3 mm in diameter and will be driven with 80-100 kJ. Prepared by LLNL under Contract DE-AC52-07NA27344.

  16. NIF Discovery Science Eagle Nebula

    Science.gov (United States)

    Kane, Jave; Martinez, David; Pound, Marc; Heeter, Robert; Huntington, Channing; Casner, Alexis; Villette, Bruno; Mancini, Roberto

    2016-10-01

    For almost 20 years a team of astronomers, theorists and experimentalists have investigated the creation of the famous Pillars of the Eagle Nebula and similar parsec-scale structures at the boundaries of HII regions in molecular hydrogen clouds, using a combination of astronomical observations, astrophysical simulations, and recently, scaled laboratory experiments. Eagle Nebula, one of the National Ignition Facility (NIF) Discovery Science programs, has completed four NIF shots to study the dense `shadowing' model of pillar formation, and been awarded more shots to study the `cometary' model. These experiments require a long-duration drive, 30 ns or longer, to generate deeply nonlinear ablative hydrodynamics. A novel x-ray source featuring multiple UV-driven hohlraums driven is used. The source directionally illuminates a science package, mimicking a cluster of stars. The first four NIF shots generated radiographs of shadowing-model pillars, and suggested that cometary structures can be generated. The velocity and column density profiles of the NIF shadowing and cometary pillars have been compared with observations of the Eagle Pillars made at millimeter observatories, and indicate cometary growth is key to matching observations. Supported in part by a Grant from the DOE OFES HEDLP program. Prepared by LLNL under Contract DE-AC52-07NA27344.

  17. Polarization in Pulsar Wind Nebulae

    CERN Document Server

    Volpi, D; Amato, E; Bucciantini, N

    2009-01-01

    The main goal of our present work is to provide, for the first time, a simple computational tool that can be used to compute the brightness, the spectral index, the polarization, the time variability and the spectrum of the non-thermal light (both synchrotron and inverse Compton, IC) associated with the plasma dynamics resulting from given relativistic magnetohydrodynamics (RMHD) simulations. The proposed method is quite general, and can be applied to any scheme for RMHD and to all non-thermal emitting sources, e.g. pulsar wind nebulae (PWNe), and in particular to the Crab Nebula (CN) as in the present proceeding. Here only the linear optical and X-ray polarization that characterizes the PWNe synchrotron emission is analyzed in order to infer information on the inner bulk flow structure, to provide a direct investigation of the magnetic field configuration, in particular the presence and the strength of a poloidal component, and to understand the origin of some emitting features, such as the knot, whose origi...

  18. Radio Properties of Pinwheel Nebulae

    CERN Document Server

    Monnier, J D; Tuthill, P G; Danchi, W C

    2002-01-01

    A small number of dusty Wolf-Rayet stars have been resolved into pinwheel nebulae, defined by their ``rotating'' spiral dust shells observed in the infrared. This morphology is naturally explained by dust formation associated with colliding winds in a binary system. In order to confirm and further explore this hypothesis, we have observed the known pinwheel nebulae (WR 104 and WR 98a) as well as the suspected binary WR 112 at multiple radio wavelengths with the Very Large Array to search for non-thermal radio emission from colliding winds. The spectrum of each target is nearly flat between 5 and 22 GHz, consistent with the presence of non-thermal emission that is reduced at low frequencies by free-free absorption. This emission must lie outside the radio ``photosphere,'' leading us to estimate a lower limit to the physical size of the non-thermal emitting region that is larger than expected from current theory. Based on a radio and infrared comparison to WR 104 and 98a, we conclude that WR 112 is a likely can...

  19. THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY

    Energy Technology Data Exchange (ETDEWEB)

    Dalcanton, Julianne J.; Williams, Benjamin F.; Rosenfield, Philip; Weisz, Daniel R.; Gilbert, Karoline M.; Gogarten, Stephanie M. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Lang, Dustin [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Lauer, Tod R.; Dong Hui [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Kalirai, Jason S.; Boyer, Martha L.; Gordon, Karl D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Seth, Anil C. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Dolphin, Andrew [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States); Bianchi, Luciana C. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Dorman, Claire E.; Guhathakurta, Puragra [University of California Observatories/Lick Observatory, University of California, 1156 High St., Santa Cruz, CA 95064 (United States); Girardi, Leo [Osservatorio Astronomico di Padova-INAF, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); and others

    2012-06-01

    The Panchromatic Hubble Andromeda Treasury is an ongoing Hubble Space Telescope Multi-Cycle Treasury program to image {approx}1/3 of M31's star-forming disk in six filters, spanning from the ultraviolet (UV) to the near-infrared (NIR). We use the Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS) to resolve the galaxy into millions of individual stars with projected radii from 0 to 20 kpc. The full survey will cover a contiguous 0.5 deg{sup 2}area in 828 orbits. Imaging is being obtained in the F275W and F336W filters on the WFC3/UVIS camera, F475W and F814W on ACS/WFC, and F110W and F160W on WFC3/IR. The resulting wavelength coverage gives excellent constraints on stellar temperature, bolometric luminosity, and extinction for most spectral types. The data produce photometry with a signal-to-noise ratio of 4 at m{sub F275W} = 25.1, m{sub F336W} = 24.9, m{sub F475W} = 27.9, m{sub F814W} = 27.1, m{sub F110W} = 25.5, and m{sub F160W} = 24.6 for single pointings in the uncrowded outer disk; in the inner disk, however, the optical and NIR data are crowding limited, and the deepest reliable magnitudes are up to 5 mag brighter. Observations are carried out in two orbits per pointing, split between WFC3/UVIS and WFC3/IR cameras in primary mode, with ACS/WFC run in parallel. All pointings are dithered to produce Nyquist-sampled images in F475W, F814W, and F160W. We describe the observing strategy, photometry, astrometry, and data products available for the survey, along with extensive testing of photometric stability, crowding errors, spatially dependent photometric biases, and telescope pointing control. We also report on initial fits to the structure of M31's disk, derived from the density of red giant branch stars, in a way that is independent of assumed mass-to-light ratios and is robust to variations in dust extinction. These fits also show that the 10 kpc ring is not just a region of enhanced recent star formation, but is instead a dynamical

  20. The Origin of T Tauri X-ray Emission: New Insights from the Chandra Orion Ultradeep Project

    CERN Document Server

    Preibisch, T; Favata, F; Feigelson, E D; Flaccomio, E; Getman, K; Micela, G; Sciortino, S; Stassun, K G; Stelzer, B; Zinnecker, H; Preibisch, Thomas; Kim, Yong -Cheol; Favata, Fabio; Feigelson, Eric D.; Flaccomio, Ettore; Getman, Konstantin; Micela, Giusi; Sciortino, Salvatore; Stassun, Keivan; Stelzer, Beate; Zinnecker, Hans

    2005-01-01

    We use the data of the Chandra Orion Ultradeep Project (COUP) to study the nearly 600 X-ray sources that can be reliably identified with optically well characterized T Tauri stars (TTS) in the Orion Nebula Cluster. We detect X-ray emission from more than 97% of the optically visible late-type (spectral types F to M) cluster stars. This proofs that there is no ``X-ray quiet'' population of late-type stars with suppressed magnetic activity. All TTS with known rotation periods lie in the saturated or super-saturated regime of the relation between activity and Rossby numbers seen for main-sequence (MS) stars, but the TTS show a much larger scatter in X-ray activity than seen for the MS stars. Strong near-linear relations between X-ray luminosities, bolometric luminosities and mass are present. We also find that the fractional X-ray luminosity rises slowly with mass over the 0.1 - 2 M_sun range. The plasma temperatures determined from the X-ray spectra of the TTS are much hotter than in MS stars, but seem to follo...

  1. Multi-Object and Long-Slit Spectroscopy of Very Low Mass Brown Dwarfs in Orion Nebular Cluster

    CERN Document Server

    Suenaga, Takuya; Kuzuhara, Masayuki; Yanagisawa, Kenshi; Ishii, Miki; Lucas, Philip W

    2013-01-01

    We present the results of a H- and K-band multi-object and long-slit spectroscopic survey of substellar mass candidates in the outer regions of the Orion Nebula Cluster. The spectra were obtained using MOIRCS on the 8.2-m Subaru telescope and ISLE on the 1.88-m telescope of Okayama Astronomical Observatory. Eight out of twelve spectra show strong water absorptions and we confirm that their effective temperatures are M6) from a chi-square fit to synthetic spectra. We plot our sources on an HR diagram overlaid with theoretical isochrones of low-mass objects and identify three new young brown dwarf candidates. One of the three new candidates is a cool object near the brown dwarf and planetary mass boundary. Based on our observations and those of previous studies, we determine the stellar (0.08 < M/Msun < 1) to substellar (0.03 < M/Msun < 0.08) mass number ratio in the outer regions of the Orion nebular cluster to be 3.5 +/- 0.8. In combination with the number ratio reported for the central region (3...

  2. Large-scale CO (J = 4-3) mapping toward the Orion-A giant molecular cloud

    Science.gov (United States)

    Ishii, Shun; Seta, Masumichi; Nagai, Makoto; Miyamoto, Yusuke; Nakai, Naomasa; Nagasaki, Taketo; Arai, Hitoshi; Imada, Hiroaki; Miyagawa, Naoki; Maezawa, Hiroyuki; Maehashi, Hideki; Bronfman, Leonardo; Finger, Ricardo

    2016-02-01

    We have mapped the Orion-A giant molecular cloud in the CO (J = 4-3) line with the Tsukuba 30 cm submillimeter telescope. The map covered a 7.125 deg2 area with a 9' resolution, including main components of the cloud such as the Orion Nebula, OMC-2/3, and L1641-N. The most intense emission was detected toward the Orion KL region. The integrated intensity ratio between CO (J = 4-3) and CO (J = 1-0) was derived using data from the Columbia-Universidad de Chile CO survey, which was carried out with a comparable angular resolution. The ratio was r4-3/1-0 ˜ 0.2 in the southern region of the cloud and 0.4-0.8 at star forming regions. We found a trend that the ratio shows higher values at the edges of the cloud. In particular, the ratio at the northeastern edge of the cloud at (l, b) ≈ (208.375°, -19.0°) shows the highest value of 1.1. The physical condition of the molecular gas in the cloud was estimated by non-LTE calculation. The result indicates that the kinetic temperature has a gradient from north (Tkin = 80 K) to south (20 K). The estimation shows that the gas associated with the edge of the cloud is warm (Tkin ˜ 60 K), dense (n_{H_2}˜ 104cm-3), and optically thin, which may be explained by heating and sweeping of interstellar materials from OB clusters.

  3. Processing NASA Earth Science Data on Nebula Cloud

    Science.gov (United States)

    Chen, Aijun; Pham, Long; Kempler, Steven

    2012-01-01

    Three applications were successfully migrated to Nebula, including S4PM, AIRS L1/L2 algorithms, and Giovanni MAPSS. Nebula has some advantages compared with local machines (e.g. performance, cost, scalability, bundling, etc.). Nebula still faces some challenges (e.g. stability, object storage, networking, etc.). Migrating applications to Nebula is feasible but time consuming. Lessons learned from our Nebula experience will benefit future Cloud Computing efforts at GES DISC.

  4. Connecting diverse molecular cloud environments with nascent protostars in Orion

    Science.gov (United States)

    Stutz, Amelia M.; Megeath, S.; Fischer, W. J.; Ali, B.; Furlan, E.; Tobin, J. J.; Stanke, T.; Henning, T.; Krause, O.; Manoj, P.; Osorio, M.; Robitaille, T.; HOPS Team

    2014-01-01

    Understanding how the gas environment within molecular clouds influences the properties of protostars is a key step towards understanding the physical factors that control star formation. We report on an analysis of the connection between molecular cloud environment and protostellar properties using the Herschel Orion Protostar Survey (HOPS), a large multi-observatory survey of protostars in the Orion molecular clouds. HOPS has produced well sampled 1 um to 870 um SEDs of over 300 protostars in the Orion molecular clouds using images and spectra from 2MASS, Spitzer, Herschel and APEX. Furthermore, the combination of APEX 870 um continuum observations with the HOPS/PACS 160 um data over the same area allows for a determination of the temperatures and column densities in the often filamentary dense gas surrounding the Orion protostars. Based on these data, we link the protostellar properties with their environmental properties. Utilizing the diverse environments present within the Orion molecular clouds, we show how the luminosity and spacing of protostars in Orion depends on the local gas column density. Furthermore, we report an unusual concentration of the youngest known protostars (the Herschel identified PBRS, PACS Bright Red Sources) in the Orion B cloud, and we discuss possible reasons for this concentration.

  5. The Panchromatic Hubble Andromeda Treasury

    CERN Document Server

    Dalcanton, J J; Lang, D; Lauer, T R; Kalirai, J S; Seth, A C; Dolphin, A; Rosenfield, P; Weisz, D R; Bell, E F; Bianchi, L C; Boyer, M L; Caldwell, N; Dong, H; Dorman, C E; Gilbert, K M; Girardi, L; Gogarten, S M; Gordon, K D; Guhathakurta, P; Hodge, P W; Holtzman, J A; Johnson, L; Larsen, S S; Lewis, A; Melbourne, J L; Olsen, K A G; Rix, H -W; Rosema, K; Saha, A; Sarajedini, A; Skillman, E D; Stanek, K Z

    2012-01-01

    The Panchromatic Hubble Andromeda Treasury (PHAT) is an on-going HST Multicycle Treasury program to image ~1/3 of M31's star forming disk in 6 filters, from the UV to the NIR. The full survey will resolve the galaxy into more than 100 million stars with projected radii from 0-20 kpc over a contiguous 0.5 square degree area in 828 orbits, producing imaging in the F275W and F336W filters with WFC3/UVIS, F475W and F814W with ACS/WFC, and F110W and F160W with WFC3/IR. The resulting wavelength coverage gives excellent constraints on stellar temperature, bolometric luminosity, and extinction for most spectral types. The photometry reaches SNR=4 at F275W=25.1, F336W=24.9, F475W=27.9, F814W=27.1, F110W=25.5, and F160W=24.6 for single pointings in the uncrowded outer disk; however, the optical and NIR data are crowding limited, and the deepest reliable magnitudes are up to 5 magnitudes brighter in the inner bulge. All pointings are dithered and produce Nyquist-sampled images in F475W, F814W, and F160W. We describe the...

  6. A recent change in the optical and γ-ray polarization of the Crab nebula and pulsar

    Science.gov (United States)

    Moran, P.; Kyne, G.; Gouiffès, C.; Laurent, P.; Hallinan, G.; Redfern, R. M.; Shearer, A.

    2016-03-01

    We report on observations of the polarization of optical and γ-ray photons from the Crab nebula and pulsar system using the Galway Astronomical Stokes Polarimeter (GASP), the Hubble Space Telescope, Advanced Camera for Surveys and the International Gamma-Ray Astrophysics Laboratory satellite (INTEGRAL). These, when combined with other optical polarization observations, suggest that the polarized optical emission and γ-ray polarization changes in a similar manner. A change in the optical polarization angle has been observed by this work, from 109.5 ± 0.7° in 2005 to 85.3 ± 1.4° in 2012. On the other hand, the γ-ray polarization angle changed from 115 ± 11° in 2003-2007 to 80 ± 12° in 2012-2014. Strong flaring activities have been detected in the Crab nebula over the past few years by the high-energy γ-ray missions Agile and Fermi, and magnetic reconnection processes have been suggested to explain these observations. The change in the polarized optical and γ-ray emission of the Crab nebula/pulsar as observed, for the first time, by GASP and INTEGRAL may indicate that reconnection is possibly at work in the Crab nebula. We also report, for the first time, a non-zero measure of the optical circular polarization from the Crab pulsar+knot system.

  7. New Explanation of Hubble's Red Shift

    Science.gov (United States)

    Cao, Dayong

    2016-03-01

    The balance system between dark massenergy (with a spacetime center) and stellar massenergy (with a massenergy center) cause a flat universe. In the flat universe, the Hubble 's redshift is caused by the Lorentz transformation (Einstein transformation). This paper will discuss about the relationship among Einstein transformation, Doppler effect, and Hubble 's redshift under the balanced and flat universe model. http://meetings.aps.org/link/BAPS.2014.APR.Y9.1

  8. The Magnetic Field Effect on Planetary Nebulae

    Institute of Scientific and Technical Information of China (English)

    A. R. Khesali; K. Kokabi

    2006-01-01

    In our previous work on the 3-dimensional dynamical structure of planetary nebulae the effect of magnetic field was not considered. Recently Jordan et al. have directly detected magnetic fields in the central stars of some planetary nebulae. This discovery supports the hypothesis that the non-spherical shape of most planetary nebulae is caused by magnetic fields in AGB stars. In this study we focus on the role of initially weak toroidal magnetic fields embedded in a stellar wind in altering the shape of the PN. We found that magnetic pressure is probably influential on the observed shape of most PNe.

  9. Interstellar gas in the Gum Nebula

    Science.gov (United States)

    Wallerstein, G.; Jenkins, E. B.; Silk, J.

    1980-01-01

    A survey of the interstellar gas near the Gum Nebula by optical observation of 67 stars at Ca II, 42 stars at Na I, and 14 stars in the UV with the Copernicus satellite provided radial velocities and column densities for all resolved absorption components. Velocity dispersions for gas in the Gum Nebula are not significantly larger than in the general interstellar medium; the ionization structure is predominantly that of an H II region with moderately high ionization. Denser, more highly ionized clouds are concentrated toward the Gum Nebula; these clouds do not show the anomalously high ionization observed in the Vela remnant clouds.

  10. Spectroscopic characterization and detection of Ethyl Mercaptan in Orion

    CERN Document Server

    Kolesniková, L; Cernicharo, J; Alonso, J L; Daly, A M; Gordon, B P; Shipman, S T

    2014-01-01

    New laboratory data of ethyl mercaptan, CH$_{3}$CH$_{2}$SH, in the millimeter and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of $gauche$-CH$_3$CH$_2$SH towards Orion KL. 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz support this identification. A detection of methyl mercaptan, CH$_{3}$SH, in the spectral survey of Orion KL is reported as well. Our column density results indicate that methyl mercaptan is $\\simeq$ 5 times more abundant than ethyl mercaptan in the hot core of Orion KL.

  11. Chemical abundances in the protoplanetary disk LV2 (Orion) - II: High dispersion VLT observations and microjet properties

    CERN Document Server

    Tsamis, Y G

    2011-01-01

    Integral field spectroscopy of the LV2 proplyd is presented taken with the VLT/FLAMES Argus array at an angular resolution of 0.31x0.31 arcsec^2 and velocity resolutions down to 2 km/s per pixel. Following subtraction of the local M42 emission, the spectrum of LV2 is isolated from the surrounding nebula. We measured the heliocentric velocities and widths of a number of lines detected in the intrinsic spectrum of the proplyd, as well as in the adjacent Orion nebula within a 6.6 x 4.2 arcsec^2 FoV. It is found that far-UV to optical collisional lines with critical densities, Ncrit, ranging from 10^3 to 10^9 /cm^3 suffer collisional de-excitation near the rest velocity of the proplyd correlating tightly with their critical densities. Lines of low Ncrit are suppressed the most. The bipolar jet arising from LV2 is spectrally and spatially well-detected in several emission lines. We compute the [O III] electron temperature profile across LV2 in velocity space and measure steep temperature variations associated with...

  12. The Eagle Nebula on NIF

    Science.gov (United States)

    Kane, Jave; Cooper, Amy; Remington, Bruce; Ryutov, Dmitri; Smalyuk, Vladimir; Pound, Marc

    2011-10-01

    In one of the eight Science on NIF campaigns, dynamics of molecular clouds such as the Eagle Nebula will be studied in scaled laboratory astrophysics experiments, focusing on new hydrodynamic stabilities of ablation fronts induced by strong directionality of a sustained radiation drive, and on the formation of cometary structures as a model for the famous Eagle Pillars. The NIF Radiation Transport Platform will be adapted to drive a foam target stood off several mm from the halfraum to simulate a molecular cloud illuminated by a distant O-type star, with the drive collimated by an aperture. Pulses of length 20-100 ns generating effective radiation temperatures of 100 eV are being sought. Design of the experiment, theory of the directional radiation instabilities, and supporting astrophysical modeling will be presented. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  13. From stellar nebula to planetesimals

    CERN Document Server

    Marboeuf, Ulysse; Alibert, Yann; Cabral, Nahuel; Benz, Willy

    2014-01-01

    Solar and extrasolar comets and extrasolar planets are the subject of numerous studies in order to determine their chemical composition and internal structure. In the case of planetesimals, their compositions are important as they govern in part the composition of future planets. The present works aims at determining the chemical composition of icy planetesimals, believed to be similar to present day comets, formed in stellar systems of solar chemical composition. The main objective of this work is to provide valuable theoretical data on chemical composition for models of planetesimals and comets, and models of planet formation and evolution. We have developed a model that calculates the composition of ices formed during the cooling of the stellar nebula. Coupled with a model of refractory element formation, it allows us to determine the chemical composition and mass ratio of ices to rocks in icy planetesimals throughout in the protoplanetary disc. We provide relationships for ice line positions (for differen...

  14. UV Timing and Spectroscopy of the Crab Nebula Pulsar

    Science.gov (United States)

    Gull, Theodore R.; Lunqvist, Peter; Sollerman, Jesper; Lindler, Don; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We have used the Hubble Space Telescope and Space Telescope Imaging Spectrograph to obtain Near Ultraviolet (NUV) (1600-3200 Angstroms) and Far Ultraviolet (FUV) (1140-1720 Angstroms) spectra and pulse profiles of the Crab Nebula's pulsar. The pulse period agrees well with the radio predictions. The NUV and FUV pulse profiles are little changed from the visible wavelength profile. Spectra obtained with the Nordic Optical Telescope were combined with the UV spectra for full coverage from 1140-9250Angstoms. Dereddening the spectrum with a standard extinction curve achieves a flat spectrum for E(B-V)=0.52, R=3.1. Lyman alpha absorption indicates a column density of 3.0=/-0.5 x 10(exp 21) cm -2, consistent with the E(B-V) of 0.52. The dereddened spectrum can be fitted by a power law with spectral index alpha=0.11+/-0.04. A broad, blueshifted absorption is seen in CIV (1550Angstroms), reaching a velocity of about 2500 kilometer per second.

  15. A two-mode planetary nebula luminosity function

    CERN Document Server

    Rodríguez-González, A; Esquivel, A; Raga, A C; Stasińska, G; Peña, M; Mayya, D

    2014-01-01

    We propose a new Planetary Nebula Luminosity Function (PNLF) that includes two populations in the distribution. Our PNLF is a direct extension of the canonical function proposed by Jacoby et al. (1987), in order to avoid problems related with the histogram construction, it is cast in terms of cumulative functions. We are interested in recovering the shape of the faint part of the PNLF in a consistent manner, for galaxies with and without a dip in their PN luminosity functions. The parameters for the two mode PNLF are obtained with a genetic algorithm, which obtains a best fit to the PNLF varying all of the parameters simultaneously in a broad parameter space. We explore a sample of 9 galaxies with various Hubble types and construct their PNLF. All of the irregular galaxies, except one, are found to be consistent with a two-mode population, while the situation is less clear for ellipticals and spirals.For the case of NGC\\, 6822, we show that the two-mode PNLF is consistent with previous studies of the star for...

  16. Nebulae and how to observe them

    CERN Document Server

    Coe, Steven

    2007-01-01

    This "Astronomers' Observing Guides" are designed for practical amateur astronomers who not only want to observe, but want to know the details of exactly what they are looking at. Nebulae are the places where the stars are born. For amateur astronomers, the many different kinds of nebulae vary from "easy" targets that can be seen with modest equipment under mediocre skies, to "challenging" objects that require experienced observers, large telescopes and excellent seeing. The concept of the book - and of the series - is to present an up-to-date detailed description and categorisation (part one); and then (part two) to consider how best to successfully observe and record the large range of astronomical objects that fall under the general heading of "nebulae". "Nebulae, and How to Observe Them" is a mine of information for all levels of amateur observers, from the beginner to the experienced.

  17. Protostars at Low Extinction in Orion A

    CERN Document Server

    Lewis, John Arban

    2016-01-01

    In the list of young stellar objects compiled by Megeath et al. (2012) for the Orion A molecular cloud, only 44 out of 1208 sources found projected onto low extinction (Ak<0.8 mag) gas are identified as protostars. These objects are puzzling because protostars are not typically expected to be associated with extended low extinction material. Here, we use high resolution extinction maps generated from Herschel data, optical/infrared and Spitzer Space Telescope photometry and spectroscopy of the low extinction protostellar candidate sources to determine if they are likely true protostellar sources or contaminants. Out of 44 candidate objects, we determine that 10 sources are likely protostars, with the rest being more evolved young stellar objects (18), galaxies (4), false detections of nebulosity and cloud edges (9), or real sources for which more data are required to ascertain their nature (3). We find none of the confirmed protostars to be associated with recognizable dense cores and we briefly discuss po...

  18. Prebiotically Important Molecules in Orion KL

    Science.gov (United States)

    Kuan, Yi-Jehng; Chuang, Yo-Ling

    Many interstellar, complex organic molecules are known to be prebiotically important and have essential functions in terrestrial biochemistry. Observations of complex organic molecular species in molecular clouds can thus enable us to test the origin of the primitive organic material found in the Solar System. Interstellar pyrimidine and glycine, the building block of nucleic acid and the simplest amino acid, respectively, are key molecules for astrobiology and were both detected in meteorites and comets. Although the formation of prebiotic molecules in extraterrestrial environments and their contribution to prebiotic chemistry and the origin of life remains unsettled, the connection between interstellar organic chemistry, meteoritic pyrimidines and amino acids, and the emergence of life on the early Earth would be strengthened with the discovery of interstellar pyrimidine and glycine. We have therefore observed the Orion KL hot molecular core to search for interstellar pyrimidine and for the confirmation of interstellar glycine using the ALMA array. We will present some of the encouraging, positive results.

  19. Observations of planetary nebulae in the Galactic Bulge

    CERN Document Server

    Cuisinier, F; Köppen, J; Acker, A; Stenholm, B

    2000-01-01

    High quality spectrophotometric observations of 30 Planetary Nebulae in the Galactic Bulge have been made. Accurate reddenings, plasma parameters, and abundances of He,O,N,S,Ar,Cl are derived. We find the abundances of O,S,Ar in the Planetary Nebulae in the Galactic Bulge to be comparable with the abundances of the Planetary Nebulae in the Disk, high abundances being maybe slightly more frequent in the Bulge. The distribution of the N/O ratio does not present in the Galactic Bulge Planetary Nebulae the extension to high values that it presents in the Disk Planetary Nebulae. We interpret this as a signature of the greater age of Bulge Planetary Nebulae. We thus find the Bulge Planetary Nebulae to be an old population, slightly more metal-rich than the Disk Planetary Nebulae. The population of the Bulge Planetary Nebulae shows hence the same characteristics than the Bulge stellar population.

  20. Submillimeter and Far-Infrared Observations of the Carina Nebula

    Science.gov (United States)

    Oberst, Thomas E.; Parshley, S. C.; Nikola, T.; Stacey, G. J.; Loehr, A.; Lane, A. P.; Stark, A. A.; Kamenetzky, J.

    2011-05-01

    We present the results of a 250 arcmin2 mapping of the 205 μm [NII] fine-structure emission over the northern Carina Nebula, including the Car I and Car II HII regions. Spectra were obtained using the South Pole Imaging Fabry-Perot Interferometer (SPIFI) at the Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) at South Pole. We supplement the 205 μm data with new reductions of far-IR fine-structure spectra from the Infrared Space Observatory (ISO) in 63 μm [OI], 122 μm [NII], 146 μm [OI], and 158 μm [CII]. Morphological comparisons are made with optical, radio continuum and CO maps. The 122 [NII] / 205 [NII] line ratio is used to probe the density of the low-ionization gas, and the 158 [C II] / 205 [NII] line ratio is used to probe the fraction of C+ arising from photodissociation regions (PDRs). From the [OI] and [CII] data, we construct a PDR model of Carina following Kaufman et al. (1999). When the PDR properties are compared with other sources, Carina is found to be more akin to 30 Doradus than Galactic star-forming regions such as the Orion Bar, M17, or W49; this is consistent with the view of Carina as a more evolved region, where much of the parent molecular cloud has been ionized or swept away. These data constitute the first ever ground-based detection of the 205 μm [NII] line, and only the third detection overall since those of the COBE FIRAS and the KAO in the early 1990s.

  1. Orion Handling Qualities During ISS Rendezvous and Docking

    Science.gov (United States)

    Hart, Jeremy J.; Stephens, J. P.; Spehar, P.; Bilimoria, K.; Foster, C.; Gonzalex, R.; Sullivan, K.; Jackson, B.; Brazzel, J.; Hart, J.

    2011-01-01

    The Orion spacecraft was designed to rendezvous with multiple vehicles in low earth orbit (LEO) and beyond. To perform the required rendezvous and docking task, Orion must provide enough control authority to perform coarse translational maneuvers while maintaining precision to perform the delicate docking corrections. While Orion has autonomous docking capabilities, it is expected that final approach and docking operations with the International Space Station (ISS) will initially be performed in a manual mode. A series of evaluations was conducted by NASA and Lockheed Martin at the Johnson Space Center to determine the handling qualities (HQ) of the Orion spacecraft during different docking and rendezvous conditions using the Cooper-Harper scale. This paper will address the specifics of the handling qualities methodology, vehicle configuration, scenarios flown, data collection tools, and subject ratings and comments. The initial Orion HQ assessment examined Orion docking to the ISS. This scenario demonstrates the Translational Hand Controller (THC) handling qualities of Orion. During this initial assessment, two different scenarios were evaluated. The first was a nominal docking approach to a stable ISS, with Orion initializing with relative position dispersions and a closing rate of approximately 0.1 ft/sec. The second docking scenario was identical to the first, except the attitude motion of the ISS was modeled to simulate a stress case ( 1 degree deadband per axis and 0.01 deg/sec rate deadband per axis). For both scenarios, subjects started each run on final approach at a docking port-to-port range of 20 ft. Subjects used the THC in pulse mode with cues from the docking camera image, window views, and range and range rate data displayed on the Orion display units. As in the actual design, the attitude of the Orion vehicle was held by the automated flight control system at 0.5 degree deadband per axis. Several error sources were modeled including Reaction

  2. A Candidate Planetary-mass Object with a Photoevaporating Disk in Orion

    Science.gov (United States)

    Fang, Min; Kim, Jinyoung Serena; Pascucci, Ilaria; Apai, Dániel; Manara, Carlo Felice

    2016-12-01

    In this work, we report the discovery of a candidate planetary-mass object with a photoevaporating protoplanetary disk, Proplyd 133-353, which is near the massive star θ 1 Ori C at the center of the Orion Nebula Cluster (ONC). The object was known to have extended emission pointing away from θ 1 Ori C, indicating ongoing external photoevaporation. Our near-infrared spectroscopic data and the location on the H-R diagram suggest that the central source of Proplyd 133-353 is substellar (˜M9.5) and has a mass probably less than 13 Jupiter mass and an age younger than 0.5 Myr. Proplyd 133-353 shows a similar ratio of X-ray luminosity to stellar luminosity to other young stars in the ONC with a similar stellar luminosity and has a similar proper motion to the mean one of confirmed ONC members. We propose that Proplyd 133-353 formed in a very low-mass dusty cloud or an evaporating gas globule near θ 1 Ori C as a second generation of star formation, which can explain both its young age and the presence of its disk.

  3. Protoplanetary Disks in the Orion OMC1 Region Imaged with ALMA

    CERN Document Server

    Eisner, J A; Ginsburg, A; Sheehan, P D

    2016-01-01

    We present ALMA observations of the Orion Nebula that cover the OMC1 outflow region. Our focus in this paper is on compact emission from protoplanetary disks. We mosaicked a field containing $\\sim 600$ near-IR-identified young stars, around which we can search for sub-mm emission tracing dusty disks. Approximately 100 sources are known proplyds identified with HST. We detect continuum emission at 1 mm wavelengths towards $\\sim 20\\%$ of the proplyd sample, and $\\sim 8\\%$ of the larger sample of near-IR objects. The noise in our maps allows 4$\\sigma$ detection of objects brighter than $\\sim 1.5$ mJy, corresponding to protoplanetary disk masses larger than 1.5 M$_{\\rm J}$ (using standard assumptions about dust opacities and gas-to-dust ratios). None of these disks are detected in contemporaneous CO(2-1) or C$^{18}$O(2-1) observations, suggesting that the gas-to-dust ratios may be substantially smaller than the canonical value of 100. Furthermore, since dust grains may already be sequestered in large bodies in ON...

  4. Extended warm gas in Orion KL as probed by methyl cyanide

    CERN Document Server

    Bell, T A; Viti, S; Marcelino, N; Palau, Aina; Esplugues, G B; Tercero, B

    2014-01-01

    In order to study the temperature distribution of the extended gas within the Orion Kleinmann-Low nebula, we have mapped the emission by methyl cyanide (CH3CN) in its J=6_K-5_K, J=12_K-11_K, J=13_K-12_K, and J=14_K-13_K transitions at an average angular resolution of ~10 arcsec (22 arcsec for the 6_K-5_K lines), as part of a new 2D line survey of this region using the IRAM 30m telescope. These fully sampled maps show extended emission from warm gas to the northeast of IRc2 and the distinct kinematic signatures of the hot core and compact ridge source components. We have constructed population diagrams for the four sets of K-ladder emission lines at each position in the maps and have derived rotational excitation temperatures and total beam-averaged column densities from the fitted slopes. In addition, we have fitted LVG model spectra to the observations to determine best-fit physical parameters at each map position, yielding the distribution of kinetic temperatures across the region. The resulting temperature...

  5. MERLIN radio detection of an interaction zone within a binary Orion proplyd system

    CERN Document Server

    Graham, M F; Garrington, S T; O'Brien, T J; Henney, W J; O'Dell, C R

    2002-01-01

    Presented here are high angular resolution MERLIN 5 GHz (6 cm) continuum observations of the binary proplyd system, LV 1 in the Orion nebula, which consists of proplyd 168--326SE and its binary proplyd companion 168--326NW (separation 0.4 arcsec). Accurate astrometric alignment allows a detailed comparison between these data and published HST PC Halpha and [Oiii] images. Thermal radio sources coincide with the two proplyds and originate in the ionized photoevaporating flows seen in the optical emission lines. Flow velocities of approx 50 km/s from the ionized proplyd surfaces and \\geq 100 km/s from a possible micro-jet have been detected using the Manchester Echelle spectrometer. A third radio source is found to coincide with a region of extended, high excitation, optical line emission that lies between the binary proplyds 168--326SE/326NW . This is modelled as a bowshock due to the collision of the photoevaporating flows from the two proplyds. Both a thermal and a non-thermal origin for the radio emission in...

  6. Discovery of an expanding molecular bubble in Orion BN/KL

    CERN Document Server

    Zapata, Luis A; Schmid-Burgk, Johannes; Rodriguez, Luis F; Ho, Paul; Patel, Nimesh A

    2010-01-01

    During their infancy, stars are well known to expel matter violently in the form of well-defined, collimated outflows. A fairly unique exception is found in the Orion BN/KL star-forming region where a poorly collimated and somewhat disordered outflow composed of numerous elongated ``finger-like'' structures was discovered more than 30 years ago. In this letter, we report the discovery in the same region of an even more atypical outflow phenomenon. Using $^{13}$CO(2-1) line observations made with the Submillimeter Array (SMA), we have identified there a 500 to 1,000 years old, expanding, roughly spherically symmetric bubble whose characteristics are entirely different from those of known outflows associated with young stellar objects. The center of the bubble coincides with the initial position of a now defunct massive multiple stellar system suspected to have disintegrated 500 years ago, and with the center of symmetry of the system of molecular fingers surrounding the Kleinmann-Low nebula. We hypothesize tha...

  7. A candidate planetary-mass object with a photoevaporating disk in Orion

    CERN Document Server

    Fang, Min; Pascucci, Ilaria; Apai, Dániel; Manara, Carlo Felice

    2016-01-01

    In this work, we report the discovery of a candidate planetary-mass object with a photoevaporating protoplanetary disk, Proplyd 133-353, which is near the massive star $\\theta^{1}$ Ori C at the center of the Orion Nebula Cluster (ONC). The object was known to have extended emission pointing away from $\\theta^{1}$ Ori C, indicating ongoing external photoevaporation. Our near-infrared spectroscopic data suggests that the central source of Proplyd 133-353 is substellar ($\\sim$M9.5), might have a mass probably less than 13 Jupiter mass and an age younger than 0.5 Myr. Proplyd 133-353 shows a similar ratio of X-ray luminosity to stellar luminosity to other young stars in the ONC with a similar stellar luminosity, and has a similar proper motion to the mean one of confirmed ONC members. We propose that Proplyd 133-353 was formed in a very low-mass dusty cloud near $\\theta^{1}$ Ori C as a second-generation of star formation, which can explain both its young age and the presence of its disk.

  8. A detailed study of the structure of the nested planetary nebula, Hb 12, the Matryoshka nebula

    Energy Technology Data Exchange (ETDEWEB)

    Clark, D. M.; López, J. A. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Campus Ensenada, Ensenada, Baja California, 22860 (Mexico); Edwards, M. L. [LBT Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Winge, C., E-mail: dmclark@astrosen.unam.mx, E-mail: jal@astrosen.unam.mx, E-mail: medwards@lbto.org, E-mail: cwinge@gemini.edu [Gemini Observatory, Southern Operations Center, c/o AURA Inc., Casilla 603, La Serena (Chile)

    2014-11-01

    We present near-IR, integral field spectroscopic observations of the planetary nebula (PN) Hb 12 using Near-infrared Integral Field Spectrograph (NIFS) on Gemini-North. Combining NIFS with the adaptive optics system Altair, we provide a detailed study of the core and inner structure of this PN. We focus the analysis in the prominent emission lines [Fe II] (1.6436 μm), He I (2.0585 μm), H{sub 2} (2.1214 μm), and Br{sub γ} (2.16553 μm). We find that the [Fe II] emission traces a tilted system of bipolar lobes, with the northern lobe being redshifted and the southern lobe blueshifted. The [Fe II] emission is very faint at the core and only present close to the systemic velocity. There is no H{sub 2} emission in the core, whereas the core is prominent in the He I and Br{sub γ} recombination lines. The H{sub 2} emission is concentrated in equatorial arcs of emission surrounding the core and expanding at ∼30 km s{sup –1}. These arcs are compared with Hubble Space Telescope images and shown to represent nested loops belonging to the inner sections of a much larger bipolar structure that replicates the inner one. The He I and Br{sub γ} emission from the core clearly show a cylindrical central cavity that seems to represent the inner walls of an equatorial density enhancement or torus. The torus is 0.''2 wide (≡200 AU radius at a distance of 2000 pc) and expanding at ≤30 km s{sup –1}. The eastern wall of the inner torus is consistently more intense than the western wall, which could indicate the presence of an off-center star, such as is observed in the similar hourglass PN, MyCn 18. A bipolar outflow is also detected in Br{sub γ} emerging within 0.''1 from the core at ∼ ± 40 km s{sup –1}.

  9. Orion Routing Protocol for Delay-Tolerant Networks

    CERN Document Server

    Medjiah, Samir; 10.1109/icc.2011.5963362

    2012-01-01

    In this paper, we address the problem of efficient routing in delay tolerant network. We propose a new routing protocol dubbed as ORION. In ORION, only a single copy of a data packet is kept in the network and transmitted, contact by contact, towards the destination. The aim of the ORION routing protocol is twofold: on one hand, it enhances the delivery ratio in networks where an end-to-end path does not necessarily exist, and on the other hand, it minimizes the routing delay and the network overhead to achieve better performance. In ORION, nodes are aware of their neighborhood by the mean of actual and statistical estimation of new contacts. ORION makes use of autoregressive moving average (ARMA) stochastic processes for best contact prediction and geographical coordinates for optimal greedy data packet forwarding. Simulation results have demonstrated that ORION outperforms other existing DTN routing protocols such as PRoPHET in terms of end-to-end delay, packet delivery ratio, hop count and first packet arr...

  10. Orion Exploration Flight Test Post-Flight Inspection and Analysis

    Science.gov (United States)

    Miller, J. E.; Berger, E. L.; Bohl, W. E.; Christiansen, E. L.; Davis, B. A.; Deighton, K. D.; Enriquez, P. A.; Garcia, M. A.; Hyde, J. L.; Oliveras, O. M.

    2017-01-01

    The multipurpose crew vehicle, Orion, is being designed and built for NASA to handle the rigors of crew launch, sustainment and return from scientific missions beyond Earth orbit. In this role, the Orion vehicle is meant to operate in the space environments like the naturally occurring meteoroid and the artificial orbital debris environments (MMOD) with successful atmospheric reentry at the conclusion of the flight. As a result, Orion's reentry module uses durable porous, ceramic tiles on almost thirty square meters of exposed surfaces to accomplish both of these functions. These durable, non-ablative surfaces maintain their surface profile through atmospheric reentry; thus, they preserve any surface imperfections that occur prior to atmospheric reentry. Furthermore, Orion's launch abort system includes a shroud that protects the thermal protection system while awaiting launch and during ascent. The combination of these design features and a careful pre-flight inspection to identify any manufacturing imperfections results in a high confidence that damage to the thermal protection system identified post-flight is due to the in-flight solid particle environments. These favorable design features of Orion along with the unique flight profile of the first exploration flight test of Orion (EFT-1) have yielded solid particle environment measurements that have never been obtained before this flight.

  11. Double Engine for a Nebula

    Science.gov (United States)

    2009-08-01

    ESO has just released a stunning new image of a field of stars towards the constellation of Carina (the Keel). This striking view is ablaze with a flurry of stars of all colours and brightnesses, some of which are seen against a backdrop of clouds of dust and gas. One unusual star in the middle, HD 87643, has been extensively studied with several ESO telescopes, including the Very Large Telescope Interferometer (VLTI). Surrounded by a complex, extended nebula that is the result of previous violent ejections, the star has been shown to have a companion. Interactions in this double system, surrounded by a dusty disc, may be the engine fuelling the star's remarkable nebula. The new image, showing a very rich field of stars towards the Carina arm of the Milky Way, is centred on the star HD 87643, a member of the exotic class of B[e] stars [1]. It is part of a set of observations that provide astronomers with the best ever picture of a B[e] star. The image was obtained with the Wide Field Imager (WFI) attached to the MPG/ESO 2.2-metre telescope at the 2400-metre-high La Silla Observatory in Chile. The image shows beautifully the extended nebula of gas and dust that reflects the light from the star. The central star's wind appears to have shaped the nebula, leaving bright, ragged tendrils of gas and dust. A careful investigation of these features seems to indicate that there are regular ejections of matter from the star every 15 to 50 years. A team of astronomers, led by Florentin Millour, has studied the star HD 87643 in great detail, using several of ESO's telescopes. Apart from the WFI, the team also used ESO's Very Large Telescope (VLT) at Paranal. At the VLT, the astronomers used the NACO adaptive optics instrument, allowing them to obtain an image of the star free from the blurring effect of the atmosphere. To probe the object further, the team then obtained an image with the Very Large Telescope Interferometer (VLTI). The sheer range of this set of observations

  12. Version 1 of the Hubble Source Catalog

    CERN Document Server

    Whitmore, Bradley C; Budavari, Tamas; Casertano, Stefano; Downes, Ronald A; Donaldson, Thomas; Fall, S Michael; Lubow, Stephen H; Quick, Lee; Strolger, Louis-Gregory; Wallace, Geoff; White, Richard L

    2016-01-01

    The Hubble Source Catalog is designed to help optimize science from the Hubble Space Telescope by combining the tens of thousands of visit-based source lists in the Hubble Legacy Archive into a single master catalog. Version 1 of the Hubble Source Catalog includes WFPC2, ACS/WFC, WFC3/UVIS, and WFC3/IR photometric data generated using SExtractor software to produce the individual source lists. The catalog includes roughly 80 million detections of 30 million objects involving 112 different detector/filter combinations, and about 160 thousand HST exposures. Source lists from Data Release 8 of the Hubble Legacy Archive are matched using an algorithm developed by Budavari & Lubow (2012). The mean photometric accuracy for the catalog as a whole is better than 0.10 mag, with relative accuracy as good as 0.02 mag in certain circumstances (e.g., bright isolated stars). The relative astrometric residuals are typically within 10 mas, with a value for the mode (i.e., most common value) of 2.3 mas. The absolute astro...

  13. Dynamo magnetic field-induced angular momentum transport in protostellar nebulae - The 'minimum mass' protosolar nebula

    Science.gov (United States)

    Stepinski, T. F.; Levy, E. H.

    1990-01-01

    Magnetic torques can produce angular momentum redistribution in protostellar nebulas. Dynamo magnetic fields can be generated in differentially rotating and turbulent nebulas and can be the source of magnetic torques that transfer angular momentum from a protostar to a disk, as well as redistribute angular momentum within a disk. A magnetic field strength of 100-1000 G is needed to transport the major part of a protostar's angular momentum into a surrounding disk in a time characteristic of star formation, thus allowing formation of a solar-system size protoplanetary nebula in the usual 'minimum-mass' model of the protosolar nebula. This paper examines the possibility that a dynamo magnetic field could have induced the needed angular momentum transport from the proto-Sun to the protoplanetary nebula.

  14. Dynamo magnetic field-induced angular momentum transport in protostellar nebulae - The minimum mass protosolar nebula

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, T.F.; Levy, E.H. (Arizona Univ., Tucson (USA))

    1990-02-01

    Magnetic torques can produce angular momentum redistribution in protostellar nebulas. Dynamo magnetic fields can be generated in differentially rotating and turbulent nebulas and can be the source of magnetic torques that transfer angular momentum from a protostar to a disk, as well as redistribute angular momentum within a disk. A magnetic field strength of 100-1000 G is needed to transport the major part of a protostar's angular momentum into a surrounding disk in a time characteristic of star formation, thus allowing formation of a solar-system size protoplanetary nebula in the usual minimum-mass model of the protosolar nebula. This paper examines the possibility that a dynamo magnetic field could have induced the needed angular momentum transport from the proto-Sun to the protoplanetary nebula. 32 refs.

  15. Testing the Copernican Principle with Hubble Parameter

    CERN Document Server

    Zhang, Tong-Jie; Ma, Cong

    2012-01-01

    By way of expressing the Hubble expansion rate for the general Lema\\^{i}tre-Tolman-Bondi (LTB) metric as a function of cosmic time, we test the scale on which the Copernican Principle holds in the context of a void model. By performing parameter estimation on the CGBH void model, we show the Hubble parameter data favors a void with characteristic radius of $2 \\sim 3$ Gpc. This brings the void model closer, but not yet enough, to harmony with observational indications given by the background kinetic Sunyaev-Zel'dovich effect and the normalization of near-infrared galaxy luminosity function. However, the test of such void models may ultimately lie in the future detection of the discrepancy between longitudinal and transverse expansion rates, a touchstone of inhomogeneous models. With the proliferation of observational Hubble parameter data and future large-scale structure observation, a definitive test could be performed on the question of cosmic homogeneity.

  16. Multiple Epoch Analysis of the Guitar Nebula and B2224+65 at Optical, X-Ray, and Radio Wavelengths

    Science.gov (United States)

    Gautam, Abhimat; Chatterjee, S.; Cordes, J. M.; Deller, A. T.; LAZIO, J.

    2013-01-01

    The Guitar Nebula is created by the interaction of the pulsar B2224+65 with the interstellar medium. We present multi-epoch observations of the nebula with the Hubble Space Telescope (HST) and the Chandra X-Ray Observatory (CXO), along with preliminary astrometric observations of B2224+65 with the Very Long Baseline Array (VLBA). The Guitar Nebula was observed in H-alpha by HST with WFPC2 (1994, 2001) and ACS (2006). The tip of the nebula head has expanded along the proper motion vector of the pulsar. Meanwhile, the sides and back of the head appear to be confined, possibly due to a density gradient in the ISM. Observations with CXO ACIS reveal an X-ray jet whose tip is coincident with the location of the pulsar, but at an angle of ~118° from the proper motion vector with a length of ~2 arcmin. Using data from 2000 and 2006, we imaged the jet at 0.3--10 keV. We did not find significant differences in the jet location or morphology between the two epochs, but our results are limited by the observation signal-to-noise ratio. PSR B2224+65 is one of the targets of PSRπ, an ongoing VLBA campaign to measure pulsar proper motions and parallaxes. When completed in 2013, PSRπ will provide both a distance and transverse velocity for PSR B2224+65 with very high precision. Based on a preliminary analysis of 5 epochs already observed, we confirm that the proper motion of the nebula tip measured with HST matches the pulsar proper motion measured with the VLBA. This project was conducted at Cornell University’s Astronomy REU program, with funding provided by the NSF.

  17. HIERARCHICAL FRAGMENTATION OF THE ORION MOLECULAR FILAMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Satoko; Ho, Paul T. P.; Su, Yu-Nung [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Teixeira, Paula S. [Institut fuer Astrophysik, Universitaet Wien, Tuerkenschanzstrasse 17, A-1180, Wien (Austria); Zapata, Luis A., E-mail: satoko_t@asiaa.sinica.edu.tw [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Morelia, Michoacan 58090 (Mexico)

    2013-01-20

    We present a high angular resolution map of the 850 {mu}m continuum emission of the Orion Molecular Cloud-3 (OMC 3) obtained with the Submillimeter Array (SMA); the map is a mosaic of 85 pointings covering an approximate area of 6.'5 Multiplication-Sign 2.'0 (0.88 Multiplication-Sign 0.27 pc). We detect 12 spatially resolved continuum sources, each with an H{sub 2} mass between 0.3-5.7 M {sub Sun} and a projected source size between 1400-8200 AU. All the detected sources are on the filamentary main ridge (n{sub H{sub 2}}{>=}10{sup 6} cm{sup -3}), and analysis based on the Jeans theorem suggests that they are most likely gravitationally unstable. Comparison of multi-wavelength data sets indicates that of the continuum sources, 6/12 (50%) are associated with molecular outflows, 8/12 (67%) are associated with infrared sources, and 3/12 (25%) are associated with ionized jets. The evolutionary status of these sources ranges from prestellar cores to protostar phase, confirming that OMC-3 is an active region with ongoing embedded star formation. We detect quasi-periodical separations between the OMC-3 sources of Almost-Equal-To 17''/0.035 pc. This spatial distribution is part of a large hierarchical structure that also includes fragmentation scales of giant molecular cloud ( Almost-Equal-To 35 pc), large-scale clumps ( Almost-Equal-To 1.3 pc), and small-scale clumps ( Almost-Equal-To 0.3 pc), suggesting that hierarchical fragmentation operates within the Orion A molecular cloud. The fragmentation spacings are roughly consistent with the thermal fragmentation length in large-scale clumps, while for small-scale cores it is smaller than the local fragmentation length. These smaller spacings observed with the SMA can be explained by either a helical magnetic field, cloud rotation, or/and global filament collapse. Finally, possible evidence for sequential fragmentation is suggested in the northern part of the OMC-3 filament.

  18. Geminga's puzzling pulsar wind nebula

    CERN Document Server

    Posselt, B; Slane, P O; Romani, R; Bucciantini, N; Bykov, A M; Kargaltsev, O; Weisskopf, M C; Ng, C -Y

    2016-01-01

    We report on six new Chandra observations of the Geminga pulsar wind nebula (PWN). The PWN consists of three distinct elongated structures - two $\\approx 0.2 d_{250}$ pc long lateral tails and a segmented axial tail of $\\approx 0.05 d_{250}$ pc length, where $d_{250}=d/(250 {\\rm pc})$. The photon indices of the power law spectra of the lateral tails, $\\Gamma \\approx 1$, are significantly harder than those of the pulsar ($\\Gamma \\approx 1.5$) and the axial tail ($\\Gamma \\approx 1.6$). There is no significant diffuse X-ray emission between the lateral tails -- the ratio of the X-ray surface brightness between the south tail and this sky area is at least 12. The lateral tails apparently connect directly to the pulsar and show indication of moving footpoints. The axial tail comprises time-variable emission blobs. However, there is no evidence for constant or decelerated outward motion of these blobs. Different physical models are consistent with the observed morphology and spectra of the Geminga PWN. In one scena...

  19. Unveiling shocks in planetary nebulae

    CERN Document Server

    Guerrero, M A; Medina, J J; Luridiana, V; Miranda, L F; Riera, A; Velázquez, P F

    2013-01-01

    The propagation of a shock wave into a medium is expected to heat the material beyond the shock, producing noticeable effects in intensity line ratios such as [O III]/Halpha. To investigate the occurrence of shocks in planetary nebulae (PNe), we have used all narrowband [O III] and Halpha images of PNe available in the HST archive to build their [O III]/Halpha ratio maps and to search for regions where this ratio is enhanced. Regions with enhanced [O III]/Halpha emission ratio can be ascribed to two different types of morphological structures: bow-shock structures produced by fast collimated outflows and thin skins enveloping expanding nebular shells. Both collimated outflows and expanding shells are therefore confirmed to generate shocks in PNe. We also find regions with depressed values of the [O III]/Halpha ratio which are found mostly around density bounded PNe, where the local contribution of [N II] emission into the F656N Halpha filter cannot be neglected.

  20. The Crab Nebula flaring activity

    Directory of Open Access Journals (Sweden)

    G. Montani

    2014-12-01

    Full Text Available The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼1015 cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼109, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  1. The Crab Nebula flaring activity

    Energy Technology Data Exchange (ETDEWEB)

    Montani, G., E-mail: giovanni.montani@frascati.enea.it [ENEA – C.R, UTFUS-MAG, via Enrico Fermi 45, I-00044 Frascati (RM) (Italy); Dipartimento di Fisica, Università di Roma “Sapienza”, p.le Aldo Moro 5, I-00185 Roma (Italy); Bernardini, M.G. [INAF – Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy)

    2014-12-12

    The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼10{sup 15} cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼10{sup 9}, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  2. Hubble Tarantula Treasury Project V. The star cluster Hodge 301: the old face of 30 Doradus

    CERN Document Server

    Cignoni, M; van der Marel, R P; Lennon, D J; Tosi, M; Grebel, E K; Gallagher, J S; Aloisi, A; de Marchi, G; Gouliermis, D A; Larsen, S; Panagia, N; Smith, L J

    2016-01-01

    Based on color-magnitude diagrams (CMDs) from the Hubble Space Telescope Hubble Tarantula Treasury Project (HTTP) survey, we present the star formation history (SFH) of Hodge~301, the oldest star cluster in the Tarantula Nebula. The HTTP photometry extends faint enough to reach, for the first time, the cluster pre-main sequence (PMS) turn-on, where the PMS joins the main sequence. Using the location of this feature, along with synthetic CMDs generated with the latest PARSEC models, we find that Hodge~301 is older than previously thought, with an age between 26.5 and 31.5 Myr. From this age, we also estimate that between 38 and 61 supernovae Type-II exploded in the region. The same age is derived from the main sequence turn-off, whereas the age derived from the post-main sequence stars is younger and between 20 and 25 Myr. Other relevant parameters are a total stellar mass of $\\approx 8800\\,\\pm 800$M$_{\\odot}$ and average reddening E(B$-$V) $\\approx 0.22-0.24$ mag, with a differential reddening $\\delta$E(B$-$V...

  3. Hydroxyl Emission in the Westbrook Nebula

    Science.gov (United States)

    Strack, Angelica; Araya, Esteban; Ghosh, Tapasi; Arce, Hector G.; Lebron, Mayra E.; Salter, Christopher J.; Minchin, Robert F.; Pihlstrom, Ylva; Kurtz, Stan; Hofner, Peter; Olmi, Luca

    2016-06-01

    CRL 618, also known as the Westbrook Nebula, is a carbon-rich pre-planetary nebula. Hydroxyl (OH) transitions are typically not detected in carbon-rich late-type stellar objects, however observations conducted with the 305m Arecibo Telescope in 2008 resulted in the detection of 4765 MHz OH emission in CRL 618. We present results of observations carried out a few months after the original detection that confirm the line. This is the first detection of 4765 MHz OH emission (most likely a maser) in a pre-planetary nebula. Follow up observations conducted in 2015 resulted in non-detection of the 4765 MHz OH transition. This behavior is consistent with the high level of variability of excited OH lines that have been detected toward a handful of other pre-planetary nebulae. Our work supports that excited OH masers are short-lived during the pre-planetary nebula phase. We also conducted a search for other OH transitions from 1612 MHz to 8611 MHz with the Arecibo Telescope; we report no other detections at rms levels of ~5 mJy.This work has made use of the computational facilities donated by Frank Rodeffer to the WIU Astrophysics Research Laboratory. We also acknowledge support from M. & C. Wong RISE scholarships and a grant from the WIU College of Arts and Sciences.

  4. European astronomers' successes with the Hubble Space Telescope*

    Science.gov (United States)

    1997-02-01

    [Figure: Laguna Nebula] Their work spans all aspects of astronomy, from the planets to the most distant galaxies and quasars, and the following examples are just a few European highlights from Hubble's second phase, 1994-96. A scarcity of midget stars Stars less massive and fainter than the Sun are much numerous in the Milky Way Galaxy than the big bright stars that catch the eye. Guido De Marchi and Francesco Paresce of the European Southern Observatory as Garching, Germany, have counted them. With the wide-field WFPC2 camera, they have taken sample censuses within six globular clusters, which are large gatherings of stars orbiting independently in the Galaxy. In every case they find that the commonest stars have an output of light that is only one-hundredth of the Sun's. They are ten times more numerous than stars like the Sun. More significant for theories of the Universe is a scarcity of very faint stars. Some astronomers have suggested that vast numbers of such stars could account for the mysterious dark matter, which makes stars and galaxies move about more rapidly than expected from the mass of visible matter. But that would require an ever-growing count of objects at low brightnesses, and De Marchi and Paresce find the opposite to be the case -- the numbers diminish. There may be a minimum size below which Nature finds starmaking difficult. The few examples of very small stars seen so far by astronomers may be, not the heralds of a multitude of dark-matter stars, but rareties. Unchanging habits in starmaking Confirmation that very small stars are scarce comes from Gerry Gilmore of the Institute of Astronomy in Cambridge (UK). He leads a European team that analyses long-exposure images in the WFPC2 camera, obtained as a by-product when another instrument is examining a selected object. The result is an almost random sample of well-observed stars and galaxies. The most remarkable general conclusion is that the make-up of stellar populations never seems to

  5. Orion Boiler Plate Airdrop Test System

    Science.gov (United States)

    Machin, Ricardo A.; Evans, Carol T.

    2013-01-01

    On the 29th of February 2012 the Orion Capsule Parachute Assembly System (CPAS) project attempted to perform an airdrop test of a boilerplate test article for the second time. The first attempt (Cluster Development Test 2, July 2008) to deliver a similar boilerplate from a C-17 using the Low Velocity Air Drop (LVAD) technique resulted in the programmer parachute failing to properly inflate, the test article failing to achieve the desired test initiation conditions, and the test article a total loss. This paper will pick up where the CDT-2 failure investigation left off, describing the test technique that was adopted, and outline the modeling that was performed to gain confidence that the second attempt would be successful. The second boiler plate test (Cluster Development Test 3-3) was indeed a complete success and has subsequently been repeated several times, allowing the CPAS project to proceed with the full scale system level development testing required to integrate the hardware to the first Entry Flight Test vehicle as well as go into the Critical Design Review with minimum risk and a mature design.

  6. A rotating molecular jet in Orion

    CERN Document Server

    Zapata, Luis A; Muders, Dirk; Schilke, Peter; Menten, Karl; Guesten, Rolf

    2009-01-01

    We present CO(2-1), $^{13}$CO(2-1), CO(6-5), CO(7-6), and SO(6$_5-5_4$) line observations made with the {\\it IRAM 30 m} and {\\it APEX} radiotelescopes and the {\\it Submillimeter Array} toward the highly collimated and extended southwest lobe of the bipolar outflow {\\it Ori-S6} located in the Orion South region. We report, for all these lines, the detection of velocity asymmetries about the flow axis, with velocity differences roughly on the order of 1 km s$^{-1}$ over distances of about 5000 AU, 4 km s$^{-1}$ over distances of about 2000 AU, and close to the source of between 7 and 11 km s$^{-1}$ over smaller scales of about 1000 AU. We interpret these velocity differences as a signature of rotation but also discuss some alternatives which we recognize as unlikely in view of the asymmetries' large downstream continuation. This rotation across the {\\it Ori-S6} outflow is observed out to (projected) distances beyond 2.5 $\\times$ 10$^4$ AU from the flow's presumed origin. Comparison of our large-scale and small-...

  7. Hierarchical Fragmentation of the Orion Molecular Filaments

    CERN Document Server

    Takahashi, Satoko; Teixeira, Paula S; Zapata, Luis A; Su, Yu-Nung

    2012-01-01

    We present a high angular resolution map of 850 um continuum emission of the Orion Molecular Cloud-3 (OMC 3) obtained with the Submillimeter Array (SMA); the map is a mosaic of 85 pointings covering an approximate area of 6'.5 x 2'.0 (0.88 x 0.27 pc). We detect 12 spatially resolved continuum sources, each with an H_2 mass between 0.3-5.7 Mo and a projected source size between 1400-8200 AU. All the detected sources are on the filamentary main ridge n_H2>10^6 cm^-3), and analysis based on the Jeans theorem suggests that they are most likely gravitationally unstable. Comparison of multi-wavelength data sets indicates that of the continuum sources, 6/12 (50 %) are associated with molecular outflows, 8/12 (67 %) are associated with infrared sources, and 3/12 (25 %) are associated with ionized jets. The evolutionary status of these sources ranges from prestellar cores to protostar phase, confirming that OMC-3 is an active region with ongoing embedded star-formation. We detect quasi-periodical separations between t...

  8. Herschel Measurements of Molecular Oxygen in Orion

    CERN Document Server

    Goldsmith, Paul F; Bell, Tom A; Black, John H; Chen, Jo-Hsin; Hollenbach, David; Kaufman, Michael J; Li, Di; Lis, Dariusz C; Melnick, Gary; Neufeld, David; Pagani, Laurent; Snell, Ronald; Benz, Arnold O; Bergin, Edwin; Bruderer, Simon; Caselli, Paola; Caux, Emmanuel; Encrenaz, Pierre; Falgarone, Edith; Gerin, Maryvonne; Goicoechea, Javier R; Hjalmarson, Ake; Larsson, Bengt; Bourlot, Jacques Le; De Luca, Franck Le Petit Massimo; Nagy, Zsofia; Roueff, Evelyne; Sandqvist, Aage; van der Tak, Floris; van Dishoeck, Ewine F; Vastel, Charlotte; Viti, Serena; Yildiz, Umut

    2011-01-01

    We report observations of three rotational transitions of molecular oxygen (O2) in emission from the H2 Peak 1 position of vibrationally excited molecular hydrogen in Orion. We observed the 487 GHz, 774 GHz, and 1121 GHz lines using HIFI on the Herschel Space Observatory, having velocities of 11 km s-1 to 12 km s-1 and widths of 3 km s-1. The beam-averaged column density is N(O2) = 6.5\\times1016 cm-2, and assuming that the source has an equal beam filling factor for all transitions (beam widths 44, 28, and 19"), the relative line intensities imply a kinetic temperature between 65 K and 120 K. The fractional abundance of O2 relative to H2 is 0.3 - 7.3\\times10-6. The unusual velocity suggests an association with a ~ 5" diameter source, denoted Peak A, the Western Clump, or MF4. The mass of this source is ~ 10 M\\odot and the dust temperature is \\geq 150 K. Our preferred explanation of the enhanced O2 abundance is that dust grains in this region are sufficiently warm (T \\geq 100 K) to desorb water ice and thus ke...

  9. Near Infrared Spectra of the Orion Bar

    CERN Document Server

    Marconi, A; Natta, A; Walmsley, C M; Spazio, D A S; Firenze, U; Arcetri, O A

    1997-01-01

    We have used the LONGSP spectrometer on the 1.5-m TIRGO telescope to obtain long slit spectra in the J, H, and K wavelength bands towards two positions along the Orion bar. These data have been supplemented with images made using the ARNICA camera mounted on TIRGO as well as with an ESO NTT observation carried out by Dr A. Moorwood. We detect a variety of transitions of hydrogen, helium, OI, FeII, FeIII, and H_2 . From our molecular hydrogen data, we conclude that densities are moderate (3-6 10^4 cm^-3) in the layer responsible for the molecular hydrogen emission and give no evidence for the presence of dense neutral clumps. We also find that the molecular hydrogen bar is likely to be tilted by ~10 degrees relative to the line of sight. We discuss the relative merits of several models of the structure of the bar and conclude that it may be split into two structures separated by 0.2-0.3 parsec along the line of sight. It also seems likely to us that in both structures, density increases along a line perpendicu...

  10. Light and heavy metal abundances in hot central stars of planetary nebulae

    CERN Document Server

    Werner, K; Jahn, D; Rauch, T; Reiff, E; Traulsen, I; Kruk, J W; Dreizler, S

    2005-01-01

    We present new results from our spectral analyses of very hot central stars achieved since the last IAU Symposium on planetary nebulae held in Canberra 2001. The analyses are mainly based on UV and far-UV spectroscopy performed with the Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer but also on ground-based observations performed at the Very Large Telescope and other observatories. We report on temperature, gravity, and abundance determinations for the CNO elements of hydrogen-rich central stars. In many hydrogen-deficient central stars (spectral type PG1159) we discovered particular neon and fluorine lines, which are observed for the very first time in any astrophysical object. Their analysis strongly confirms the idea that these stars exhibit intershell matter as a consequence of a late helium-shell flash.

  11. Flows along cometary tails in the Helix planetary nebula NGC 7293

    CERN Document Server

    Meaburn, John

    2009-01-01

    Previous velocity images which reveal flows of ionized gas along the most prominent cometary tail (from Knot 38) in the Helix planetary nebula are compared with that taken at optical wavelengths with the Hubble Space Telescope and with an image in the emission from molecular hydrogen. The flows from the second most prominent tail from Knot 14 are also considered. The kinematics of the tail from the more complex Knot 32, shown here for the first time, also reveals an acceleration away from the central star. All of the tails are explained as accelerating ionized flows of ablated material driven by the previous, mildly supersonic, AGB wind from the central star. The longest tail of ionized gas, even though formed by this mechanism in a very clumpy medium, as revealed by the emission from molecular hydrogen, appears to be a coherent outflowing feature.

  12. The Radio Spectral Index of the Crab Nebula

    Science.gov (United States)

    1997-11-20

    We present the results of a new, comprehensive investigation of the radio spectral index of the Crab Nebula supernova remnant. New data at 74 MHz are...thermal material in the Crab Nebula’s filaments. Apart from some possible renewed acceleration occurring in the wisps, the dominant accelerator of relativistic electrons in the Crab Nebula is the pulsar itself.

  13. The Hubble Flow of Plateau Inflation

    NARCIS (Netherlands)

    Coone, Dries; Roest, Diederik; Vennin, Vincent

    2015-01-01

    In the absence of CMB precision measurements, a Taylor expansion has often been invoked to parametrize the Hubble flow function during inflation. The standard "horizon flow" procedure implicitly relies on this assumption. However, the recent Planck results indicate a strong preference for plateau

  14. The Hubble Flow of Plateau Inflation

    NARCIS (Netherlands)

    Coone, Dries; Roest, Diederik; Vennin, Vincent

    2015-01-01

    In the absence of CMB precision measurements, a Taylor expansion has often been invoked to parametrize the Hubble flow function during inflation. The standard "horizon flow" procedure implicitly relies on this assumption. However, the recent Planck results indicate a strong preference for plateau in

  15. The Hubble Space Telescope: Problems and Solutions.

    Science.gov (United States)

    Villard, Ray

    1990-01-01

    Presented is the best understanding of the flaw discovered in the optics of the Hubble Space Telescope and the possible solutions to the problems. The spherical aberration in the telescope's mirror and its effect on the quality of the telescope's imaging ability is discussed. (CW)

  16. Hubble Exoplanet Pro/Am Collaboration (Abstract)

    Science.gov (United States)

    Conti, D. M.

    2016-06-01

    (Abstract only) A collaborative effort is being organized between a world-wide network of amateur astronomers and a Hubble Space Telescope (HST) science team. The purpose of this collaboration is to supplement an HST near-infrared spectroscopy survey of some 15 exoplanets with ground-based observations in the visible range.

  17. Dark Energy and the Hubble Law

    Science.gov (United States)

    Chernin, A. D.; Dolgachev, V. P.; Domozhilova, L. M.

    The Big Bang predicted by Friedmann could not be empirically discovered in the 1920th, since global cosmological distances (more than 300-1000 Mpc) were not available for observations at that time. Lemaitre and Hubble studied receding motions of galaxies at local distances of less than 20-30 Mpc and found that the motions followed the (nearly) linear velocity-distance relation, known now as Hubble's law. For decades, the real nature of this phenomenon has remained a mystery, in Sandage's words. After the discovery of dark energy, it was suggested that the dynamics of local expansion flows is dominated by omnipresent dark energy, and it is the dark energy antigravity that is able to introduce the linear velocity-distance relation to the flows. It implies that Hubble's law observed at local distances was in fact the first observational manifestation of dark energy. If this is the case, the commonly accepted criteria of scientific discovery lead to the conclusion: In 1927, Lemaitre discovered dark energy and Hubble confirmed this in 1929.

  18. Local gravitational physics of the Hubble expansion

    CERN Document Server

    Kopeikin, Sergei

    2014-01-01

    We study physical consequences of the Hubble expansion of FLRW manifold on measurement of space, time and light propagation in the local inertial frame. We analyse the solar system radar ranging and Doppler tracking experiments, and time synchronization. FLRW manifold is covered by global coordinates (t,y^i), where t is the cosmic time coinciding with the proper time of the Hubble observers. We introduce local inertial coordinates x^a=(x^0,x^i) in the vicinity of a world line of a Hubble observer with the help of a special conformal transformation. The local inertial metric is Minkowski flat and is materialized by the congruence of time-like geodesics of static observers being at rest with respect to the local spatial coordinates x^i. We consider geodesic motion of test particles and notice that the local coordinate time x^0=x^0(t) taken as a parameter along the world line of particle, is a function of the Hubble's observer time t. This function changes smoothly from x^0=t for a particle at rest (observer's c...

  19. Monitoring the Crab Nebula with LOFT

    Science.gov (United States)

    Wilson-Hodge, Colleen A.

    2012-01-01

    From 2008-2010, the Crab Nebula was found to decline by 7% in the 15-50 keV band, consistently in Fermi GBM, INTEGRAL IBIS, SPI, and JEMX, RXTE PCA, and Swift BAT. From 2001-2010, the 15-50 keV flux from the Crab Nebula typically varied by about 3.5% per year. Analysis of RXTE PCA data suggests possible spectral variations correlated with the flux variations. I will present estimates of the LOFT sensitivity to these variations. Prior to 2001 and since 2010, the observed flux variations have been much smaller. Monitoring the Crab with the LOFT WFM and LAD will provide precise measurements of flux variations in the Crab Nebula if it undergoes a similarly active episode.

  20. High energy neutrinos from pulsar wind nebulae

    Science.gov (United States)

    Di Palma, Irene

    2017-09-01

    Several Pulsar Wind Nebulae have been detected in the TeV band in the last decade.The TeV emission is typically interpreted in a purely leptonic scenario, but this usually requires that the magnetic field in the Nebula be much lower than the equipartition value and the assumption of an enhanced target radiation at IR frequencies. In this work we consider the possibility that, in addition to the relativistic electrons, also relativistic hadrons are present in these nebulae. Assuming that part of the emitted TeV photons are of hadronic origin, we compute the associated flux of ∼ 1 ‑ 100 TeV neutrinos. We use the IceCube non detection to put constraints on the fraction of TeV photons that might be contributed by hadrons and estimate the number of neutrino events that can be expected from these sources in IceCube, ANTARES and in KM3Net.

  1. Orion Relative Navigation Flight Software Analysis and Design

    Science.gov (United States)

    D'Souza, Chris; Christian, John; Zanetti, Renato

    2011-01-01

    The Orion relative Navigation System has sought to take advantage of the latest developments in sensor and algorithm technology while living under the constraints of mass, power, volume, and throughput. In particular, the only sensor specifically designed for relative navigation is the Vision Navigation System (VNS), a lidar-based sensor. But it uses the Star Trackers, GPS (when available) and IMUs, which are part of the overall Orion navigation sensor suite, to produce a relative state accurate enough to dock with the ISS. The Orion Relative Navigation System has significantly matured as the program has evolved from the design phase to the flight software implementation phase. With the development of the VNS system and the STORRM flight test of the Orion Relative Navigation hardware, much of the performance of the system will be characterized before the first flight. However challenges abound, not the least of which is the elimination of the RF range and range-rate system, along with the development of the FSW in the Matlab/Simulink/Stateflow environment. This paper will address the features and the rationale for the Orion Relative Navigation design as well as the performance of the FSW in a 6-DOF environment as well as the initial results of the hardware performance from the STORRM flight.

  2. Evolution of column density distributions within Orion~A

    CERN Document Server

    Stutz, A M

    2015-01-01

    We compare the structure of star-forming molecular clouds in different regions of Orion A to determine how the column density probability distribution function (N-PDF) varies with environmental conditions such as the fraction of young protostars. A correlation between the N-PDF slope and Class 0 protostar fraction has been previously observed in a low-mass star-formation region (Perseus) by Sadavoy; here we test if a similar correlation is observed in a high-mass star-forming region. We use Herschel data to derive a column density map of Orion A. We use the Herschel Orion Protostar Survey catalog for accurate identification and classification of the Orion A young stellar object (YSO) content, including the short-lived Class 0 protostars (with a $\\sim$ 0.14 Myr lifetime). We divide Orion A into eight independent 13.5 pc$^2$ regions; in each region we fit the N-PDF distribution with a power-law, and we measure the fraction of Class 0 protostars. We use a maximum likelihood method to measure the N-PDF power-law ...

  3. A 1.3 cm Line Survey toward Orion KL

    CERN Document Server

    Gong, Y; Thorwirth, S; Spezzano, S; Menten, K M; Walmsley, C M; Wyrowski, F; Mao, R Q; Klein, B

    2015-01-01

    Orion KL has served as a benchmark for spectral line searches throughout the (sub)millimeter regime. The main goal is to systematically study spectral characteristics of Orion KL in the 1.3 cm band. We carried out a spectral line survey (17.9 GHz to 26.2 GHz) with the Effelsberg-100 m telescope towards Orion KL. We find 261 spectral lines, yielding an average line density of about 32 spectral features per GHz above 3$\\sigma$. The identified lines include 164 radio recombination lines (RRLs) and 97 molecular lines. A total of 23 molecular transitions from species known to exist in Orion KL are detected for the first time in the interstellar medium. Non-metastable 15NH3 transitions are detected in Orion KL for the first time. Based on the velocity information of detected lines and the ALMA images, the spatial origins of molecular emission are constrained and discussed. A narrow feature is found in SO2 ($8_{1,7}-7_{2,6}$), possibly suggesting the presence of a maser line. Column densities and fractional abundanc...

  4. HUBBLE SEES A VAST 'CITY' OF STARS

    Science.gov (United States)

    2002-01-01

    In these pictures, a 'city' of a million stars glitters like a New York City skyline. The images capture the globular cluster 47 Tucanae, located 15,000 light-years from Earth in the southern constellation Tucana. Using NASA's Hubble Space Telescope, astronomers went hunting in this large city for planetary companions: bloated gaseous planets that snuggle close to their parent stars, completing an orbit in a quick three to five days. To their surprise, they found none. This finding suggests that the cluster's environment is too hostile for breeding planets or that it lacks the necessary elements for making them. The picture at left, taken by a terrestrial telescope, shows most of the cluster, a tightly packed group of middle-aged stars held together by mutual gravitational attraction. The box near the center represents the Hubble telescope's view. The image at right shows the Hubble telescope's close-up look at a swarm of 35,000 stars near the cluster's central region. The stars are tightly packed together: They're much closer together than our Sun and its closest stars. The picture, taken by the Wide Field and Planetary Camera 2, depicts the stars' natural colors and tells scientists about their composition and age. For example, the red stars denote bright red giants nearing the end of their lives; the more common yellow stars are similar to our middle-aged Sun. Most of the stars in the cluster are believed to have formed about 10 billion years ago. The bright, blue stars -- thought to be remnants of stellar collisions and mergers -- provide a few rejuvenated, energetic stars in an otherwise old system. The Hubble picture was taken in July 1999. Credits for Hubble image: NASA and Ron Gilliland (Space Telescope Science Institute) Credits for ground-based image: David Malin, c Anglo-Australian Observatory

  5. Ultraviolet studies of the Crab Nebula

    Science.gov (United States)

    Talavera, A.

    2017-03-01

    The Crab Nebula (Messier 1) is one of the most observed sources with the XMM-Newton space telescope of ESA. The Crab and its related pulsar are a calibration source for the on-board X-rays cameras. There are around 80 observations between 2000 and 2015. In this observations, the XMM-Newton Optical and UV Monitor (OM) has also been used. We present a preliminary study of the Crab using images obtained the OM UV filters at 291, 231 and 212 nm. Photometric data for the pulsar (PSR0531+21), created in the supernova event of AD 1054 origin of the nebula, are also presented

  6. Dust Extinction in Compact Planetary Nebulae

    OpenAIRE

    Lee, TH; Kwok, S.

    2005-01-01

    The effects of dust extinction on the departure from axisymmetry in the morphology of planetary nebulae (PNs) are investigated through a comparison of the radio free-free emission and hydrogen recombination line images. The dust extinction maps from five compact PNs are derived using high-resolution (̃0"1) Hα and radio maps of the HST and VLA. These extinction maps are then analyzed by an ellipsoidal shell ionization model including the effects of dust extinction to infer the nebulae's intrin...

  7. A non-equilibrium ortho-to-para ratio of water in the Orion PDR

    NARCIS (Netherlands)

    Choi, Y.; van der Tak, F. F. S.; Bergin, E. A.; Plume, R.

    2014-01-01

    Context. The ortho-to-para ratio (OPR) of H2O is thought to be sensitive to the temperature of water formation. The OPR of H2O is thus useful for studying the formation mechanism of water. Aims: We investigate the OPR of water in the Orion PDR (photon-dominated region), at the Orion Bar and Orion S

  8. SPECTROSCOPIC CHARACTERIZATION AND DETECTION OF ETHYL MERCAPTAN IN ORION

    Energy Technology Data Exchange (ETDEWEB)

    Kolesniková, L.; Alonso, J. L.; Daly, A. M. [Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid (Spain); Tercero, B.; Cernicharo, J. [Departamento de Astrofísica, Centro de Astrobiología CAB, CSIC-INTA, Ctra. de Torrejón a Ajalvir km 4, E-28850 Madrid (Spain); Gordon, B. P.; Shipman, S. T., E-mail: lucie.kolesnikova@uva.es, E-mail: jlalonso@qf.uva.es, E-mail: adammichael.daly@uva.es, E-mail: terceromb@cab.inta-csic.es, E-mail: jcernicharo@cab.inta-csic.es, E-mail: brittany.gordon@ncf.edu, E-mail: shipman@ncf.edu [Division of Natural Sciences, New College of Florida, Sarasota, FL 34243 (United States)

    2014-03-20

    New laboratory data of ethyl mercaptan, CH{sub 3}CH{sub 2}SH, in the millimeter- and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of gauche-CH{sub 3}CH{sub 2}SH toward Orion KL. This identification is supported by 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz. A detection of methyl mercaptan, CH{sub 3}SH, in the spectral survey of Orion KL is reported as well. Our column density results indicate that methyl mercaptan is ≅ 5 times more abundant than ethyl mercaptan in the hot core of Orion KL.

  9. Orion: a glimpse of hope in life span extension?

    Science.gov (United States)

    Muradian, K; Bondar, V; Bezrukov, V; Zhukovsky, O; Polyakov, V; Utko, N

    2010-01-01

    Orion is a multicomponent drug based on derivatives of taurocholic acid and several other compounds. Application of Orion into the feeding medium of Drosophila melanogaster resulted in increased life span and survival at stressful conditions. Two paradoxical features of the drug should be stressed: The "age-threshold" (life span extension was observed only when the drug was applied starting from the second half of life) and induction of "centenarian" flies (older 100 days). Orion enhanced survival at heat shock (38 degrees C) and acidic (pH = 1.6) or alkaline (pH = 11.8) feeding mediums, but not at oxidative stresses modeled by 100% oxygen or application of hydrogen peroxide (H(2)O(2)).

  10. Crew Exploration Vehicle (CEV) (Orion) Occupant Protection. Part 1; Appendices

    Science.gov (United States)

    Currie-Gregg, Nancy J.; Gernhardt, Michael L.; Lawrence, Charles; Somers, Jeffrey T.

    2016-01-01

    Dr. Nancy J. Currie, of the NASA Engineering and Safety Center (NESC), Chief Engineer at Johnson Space Center (JSC), requested an assessment of the Crew Exploration Vehicle (CEV) occupant protection as a result of issues identified by the Constellation Program and Orion Project. The NESC, in collaboration with the Human Research Program (HRP), investigated new methods associated with occupant protection for the Crew Exploration Vehicle (CEV), known as Orion. The primary objective of this assessment was to investigate new methods associated with occupant protection for the CEV, known as Orion, that would ensure the design provided minimal risk to the crew during nominal and contingency landings in an acceptable set of environmental and spacecraft failure conditions. This documents contains the appendices to the NESC assessment report. NASA/TM-2013-217380, Application of the Brinkley Dynamic Response Criterion to Spacecraft Transient Dynamic Events supersedes this document.

  11. Young Stellar Objects in the Orion B Cloud

    Science.gov (United States)

    Petr-Gotzens, M. G.; Alcalá, J. M.; Spezzi, L.; Jørgensen, J. K.; Stanke, Th.; Lombardi, M.; Alves, J. F.

    2015-12-01

    Wide-field near-infrared imaging surveys offer an excellent opportunity to obtain spatially complete samples of young stars in nearby star-forming regions. By studying their spatial distribution and individual properties, the global star formation characteristics of a region can be established. Near-infrared wide-field imaging observations of a significantly large area in the Orion Molecular Cloud B, obtained with the VISTA telescope on Cerro Paranal are presented. On the basis of photometric selection criteria, we have identified 186 candidate young stellar objects that are associated with the stellar clusters NGC 2068 and NGC 2071, and with the stellar group around HH24-26. Overall, Orion B shows a lot of similarities in its star formation characteristics with other Galactic star-forming regions: a star formation efficiency of a few percent, a stellar mass distribution very similar to that of the Orion Trapezium cluster, and a high observed fraction of circumstellar discs.

  12. The large system of molecular clouds in Orion and Monoceros

    Science.gov (United States)

    Maddalena, R. J.; Moscowitz, J.; Thaddeus, P.; Morris, M.

    1986-01-01

    Emission is noted over about one-eighth of an 850-sq deg region centered on Orion and Monoceros that has been surveyed in the J = 1 to 0 line of CO; most of the emission arises from giant molecular clouds associated with Orion A and B, and Mon R2. A much smaller area was surveyed for C-13O emission. A comparison of cloud masses obtained by three independent methods indicates that CO luminosity is as accurate a measure of cloud mass as other indicators. The possible relationships among clouds in the survey are discussed, including the conjecture that the overall Orion complex of clouds is a much larger system than previously considered, incorporating most of the clouds in the present survey.

  13. Kompaneets Model Fitting of the Orion-Eridanus Superbubble

    CERN Document Server

    Pon, Andy; Bally, John; Heiles, Carl

    2014-01-01

    Winds and supernovae from OB associations create large cavities in the interstellar medium referred to as superbubbles. The Orion molecular clouds are the nearest high mass star-forming region and have created a highly elongated, 20 degree x 45 degree, superbubble. We fit Kompaneets models to the Orion-Eridanus superbubble and find that a model where the Eridanus side of the superbubble is oriented away from the Sun provides a marginal fit. Because this model requires an unusually small scale height of 40 pc and has the superbubble inclined 35 degrees from the normal to the Galactic plane, we propose that this model should be treated as a general framework for modeling the Orion-Eridanus superbubble, with a secondary physical mechanism not included in the Kompaneets model required to fully account for the orientation and elongation of the superbubble.

  14. Orion Crew Member Injury Predictions during Land and Water Landings

    Science.gov (United States)

    Lawrence, Charles; Littell, Justin D.; Fasanella, Edwin L.; Tabiei, Ala

    2008-01-01

    A review of astronaut whole body impact tolerance is discussed for land or water landings of the next generation manned space capsule named Orion. LS-DYNA simulations of Orion capsule landings are performed to produce a low, moderate, and high probability of injury. The paper evaluates finite element (FE) seat and occupant simulations for assessing injury risk for the Orion crew and compares these simulations to whole body injury models commonly referred to as the Brinkley criteria. The FE seat and crash dummy models allow for varying the occupant restraint systems, cushion materials, side constraints, flailing of limbs, and detailed seat/occupant interactions to minimize landing injuries to the crew. The FE crash test dummies used in conjunction with the Brinkley criteria provides a useful set of tools for predicting potential crew injuries during vehicle landings.

  15. HST STIS Observations of the Mixing Layer in the Cat’s Eye Nebula

    Science.gov (United States)

    Fang, Xuan; Guerrero, Martín A.; Toalá, Jesús A.; Chu, You-Hua; Gruendl, Robert A.

    2016-05-01

    Planetary nebulae (PNe) are expected to have a ˜105 K interface layer between the ≥slant 106 K inner hot bubble and the ˜104 K optical nebular shell. The PN structure and evolution, and the X-ray emission, depend critically on the efficiency of the mixing of material at this interface layer. However, neither its location nor its spatial extent have ever been determined. Using high-spatial resolution HST STIS spectroscopic observations of the N v λ λ 1239,1243 lines in the Cat’s Eye Nebula (NGC 6543), we have detected this interface layer and determined its location, extent, and physical properties for the first time in a PN. We confirm that this interface layer, as revealed by the spatial distribution of the N v λ1239 line emission, is located between the hot bubble and the optical nebular shell. We estimate a thickness of 1.5× {10}16 cm and an electron density of ˜200 cm-3 for the mixing layer. With a thermal pressure of ˜2 × 10-8 dyn cm-2, the mixing layer is in pressure equilibrium with the hot bubble and ionized nebular rim of NGC 6543. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. The observations are associated with program #12509.

  16. Central Stars of Planetary Nebulae in the Large Magellanic Cloud: A Far-UV Spectroscopic Analysis

    CERN Document Server

    Herald, J E

    2004-01-01

    We observed seven central stars of planetary nebulae (CSPN) in the Large Magellanic Cloud (LMC) with the Far Ultraviolet Spectroscopic Explorer (FUSE), and performed a model-based analysis of these spectra in conjunction with Hubble Space Telescope (HST) spectra in the UV and optical range to determine the stellar and nebular parameters. Most of the objects show wind features, and they have effective temperatures ranging from 38 to 60 kK with mass-loss rates of ~= 5x10^-8 Msun/yr. Five of the objects have typical LMC abundances. One object (SMP LMC 61) is a [WC4] star, and we fit its spectra with He/C/O-rich abundances typical of the [WC] class, and find its atmosphere to be iron-deficient. Most objects have very hot (T ~> 2000 K) molecular hydrogen in their nebulae, which may indicate a shocked environment. One of these (SMP LMC 62) also displays OVI 1032-38 nebular emission lines, rarely observed in PN.

  17. The Nucleus of the Planetary Nebula EGB 6 as a Post-Mira Binary

    CERN Document Server

    Bond, Howard E; Esplin, Taran L; Hawley, Steven A; Liebert, James; Munari, Ulisse

    2016-01-01

    EGB 6 is a faint, large, ancient planetary nebula (PN). Its central star, a hot DAOZ white dwarf (WD), is a prototype of a rare class of PN nuclei associated with dense, compact emission-line knots. The central star also shows excess fluxes in both the near- (NIR) and mid-infrared (MIR). In a 2013 paper, we used Hubble Space Telescope (HST) images to show that the compact nebula is a point-like source, located 0".16 (~118 AU) from the WD. We attributed the NIR excess to an M dwarf companion star, which appeared to coincide with the dense emission knot. We now present new ground-based NIR spectroscopy, showing that the companion is actually a much cooler source with a continuous spectrum, apparently a dust-enshrouded low-luminosity star. New HST images confirm common proper motion of the emission knot and red source with the WD. The I-band, NIR, and MIR fluxes are variable, possibly on timescales as short as days. We can fit the spectral-energy distribution with four blackbodies (the WD, a ~1850 K NIR componen...

  18. Visualization of Astronomical Nebulae via Distributed Multi-GPU Compressed Sensing Tomography.

    Science.gov (United States)

    Wenger, S; Ament, M; Guthe, S; Lorenz, D; Tillmann, A; Weiskopf, D; Magnor, M

    2012-12-01

    The 3D visualization of astronomical nebulae is a challenging problem since only a single 2D projection is observable from our fixed vantage point on Earth. We attempt to generate plausible and realistic looking volumetric visualizations via a tomographic approach that exploits the spherical or axial symmetry prevalent in some relevant types of nebulae. Different types of symmetry can be implemented by using different randomized distributions of virtual cameras. Our approach is based on an iterative compressed sensing reconstruction algorithm that we extend with support for position-dependent volumetric regularization and linear equality constraints. We present a distributed multi-GPU implementation that is capable of reconstructing high-resolution datasets from arbitrary projections. Its robustness and scalability are demonstrated for astronomical imagery from the Hubble Space Telescope. The resulting volumetric data is visualized using direct volume rendering. Compared to previous approaches, our method preserves a much higher amount of detail and visual variety in the 3D visualization, especially for objects with only approximate symmetry.

  19. Observing Planetary Nebulae with JWST and Extremely Large Telescopes

    Science.gov (United States)

    Sahai, Raghvendra

    2015-01-01

    Most stars in the Universe that leave the main sequence in a Hubble time will end their lives evolving through the Planetary Nebula (PN) evolutionary phase. The heavy mass loss which occurs during the preceding AGB phase is important across astrophysics, dramatically changing the course of stellar evolution, dominantly contributing to the dust content of the interstellar medium, and influencing its chemical composition. The evolution from the AGB phase to the PN phases remains poorly understood, especially the dramatic transformation that occurs in the morphology of the mass-ejecta as AGB stars and their round circumstellar envelopes evolve into mostly PNe, the majority of which deviate strongly from spherical symmetry. In addition, although the PN [OIII] luminosity function (PNLF) has been used as a standard candle (on par with distance indicators such as Cepheids), we do not understand why it works. It has been argued that the resolution of these issues may be linked to binarity and associated processes such as mass transfer and common envelope evolution.Thus, understanding the formation and evolution of PNe is of wide astrophysical importance. PNe have long been known to emit across a very large span of wavelengths, from the radio to X-rays. Extensive use of space-based observatories at X-ray (Chandra/ XMM-Newton), optical (HST) and far-infrared (Spitzer, Herschel) wavelengths in recent years has produced significant new advances in our knowledge of these objects. Given the expected advent of the James Webb Space Telescope in the near future, and ground-based Extremely Large Telescope(s) somewhat later, this talk will focus on future high-angular-resolution, high-sensitivity observations at near and mid-IR wavelengths with these facilities that can help in addressing the major unsolved problems in the study of PNe.

  20. Planetary nebulae as tracers of galaxy stellar populations

    Science.gov (United States)

    Buzzoni, Alberto; Arnaboldi, Magda; Corradi, Romano L. M.

    2006-05-01

    We address the general problem of the luminosity-specific planetary nebula (PN) number, better known as the `α' ratio, given by α=NPN/Lgal, and its relationship with the age and metallicity of the parent stellar population. Our analysis relies on population synthesis models that account for simple stellar populations (SSPs), and more elaborate galaxy models covering the full star formation range of the different Hubble morphological types. This theoretical framework is compared with the updated census of the PN population in Local Group (LG) galaxies and external ellipticals in the Leo group, and the Virgo and Fornax clusters. The main conclusions of our study can be summarized as follows. (i) According to the post-asymptotic giant branch (AGB) stellar core mass, PN lifetime in a SSP is constrained by three relevant regimes, driven by the nuclear (Mcore>~ 0.57Msolar), dynamical (0.57Msolar>~Mcore>~ 0.55Msolar) and transition (0.55Msolar>~Mcore>~ 0.52Msolar) time-scales. The lower limit for Mcore also sets the minimum mass for stars to reach the AGB thermal-pulsing phase and experience the PN event. (ii) Mass loss is the crucial mechanism to constrain the value of α, through the definition of the initial-to-final mass relation (IFMR). The Reimers mass-loss parametrization, calibrated on Pop II stars of Galactic globular clusters, poorly reproduces the observed value of α in late-type galaxies, while a better fit is obtained using the empirical IFMR derived from white dwarf observations in the Galaxy open clusters. (iii) The inferred PN lifetime for LG spirals and irregulars exceeds 10000yr, which suggests that Mcore~ 0.7Msolar PNe in order to preserve the constancy of the bright luminosity-function cut-off magnitude in ellipticals, must be confined to a small fraction (a few per cent at most) of the whole galaxy PN population.

  1. HST optical polarimetry of the Vela pulsar and nebula

    Science.gov (United States)

    Moran, P.; Mignani, R. P.; Shearer, A.

    2014-11-01

    Polarization measurements of pulsars offer a unique insight into the geometry of the emission regions in the neutron star magnetosphere. Therefore, they provide observational constraints on the different models proposed for the pulsar emission mechanisms. Optical polarization data of the Vela pulsar was obtained from the Hubble Space Telescope (HST) archive. The data, obtained in two filters (F606W, central wavelength = 590.70 nm and F550M, central wavelength = 558.15 nm), consist of a series of observations of the pulsar taken with the HST/Advanced Camera for Surveys and cover a time span of 5 d. These data have been used to carry out the first high spatial resolution and multi-epoch study of the polarization of the pulsar. We produced polarization vector maps of the region surrounding the pulsar and measured the degree of linear polarization (P.D.) and the position angle (P.A.) of the pulsar's integrated pulse beam. We obtained P.D. = 8.1 ± 0.7 per cent and P.A. = 146.3° ± 2.4°, averaged over the time span covered by these observations. These results not only confirm those originally obtained by Wagner & Seifert and Mignani et al., both using the Very Large Telescope, but are of greater precision. Furthermore, we confirm that the P.A. of the pulsar polarization vector is aligned with the direction of the pulsar proper motion. The pulsar wind nebula is undetected in polarized light as is the case in unpolarized light, down to a flux limit of 26.8 mag arcsec-2.

  2. Measurements of Wide Tycho Double Stars in Orion

    Science.gov (United States)

    Knapp, Wilfried; McPhee, Mark

    2016-10-01

    About 25 TDS objects in Orion with separation of 1.5" or larger remained at the beginning of 2016 in the WDS catalog without confirmation while 10 are listed as confirmed. Several of the so far unconfirmed objects have now been successfully observed while most of the remaining objects are to be suspected as being bogus as the evidence suggests single stars. The number of confirmed TDS objects of this separation range in Orion is greater than in the other constellations we have studied so far.

  3. Spectroscopic characterization and detection of Ethyl Mercaptan in Orion

    OpenAIRE

    Kolesniková, L.,; Tercero, B.; Cernicharo, J.; Alonso, J. L.; Daly, A. M.; Gordon, B. P.; Shipman, S. T.

    2014-01-01

    New laboratory data of ethyl mercaptan, CH$_{3}$CH$_{2}$SH, in the millimeter and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of $gauche$-CH$_3$CH$_2$SH towards Orion KL. 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz support this identification. A detection of methyl mercaptan, CH$_{3}$SH, in the spectral survey of Orion KL is reported as well. Our column density ...

  4. Orion Launch Abort System Performance During Exploration Flight Test 1

    Science.gov (United States)

    McCauley, Rachel; Davidson, John; Gonzalez, Guillo

    2015-01-01

    The Orion Launch Abort System Office is taking part in flight testing to enable certification that the system is capable of delivering the astronauts aboard the Orion Crew Module to a safe environment during both nominal and abort conditions. Orion is a NASA program, Exploration Flight Test 1 is managed and led by the Orion prime contractor, Lockheed Martin, and launched on a United Launch Alliance Delta IV Heavy rocket. Although the Launch Abort System Office has tested the critical systems to the Launch Abort System jettison event on the ground, the launch environment cannot be replicated completely on Earth. During Exploration Flight Test 1, the Launch Abort System was to verify the function of the jettison motor to separate the Launch Abort System from the crew module so it can continue on with the mission. Exploration Flight Test 1 was successfully flown on December 5, 2014 from Cape Canaveral Air Force Station's Space Launch Complex 37. This was the first flight test of the Launch Abort System preforming Orion nominal flight mission critical objectives. The abort motor and attitude control motors were inert for Exploration Flight Test 1, since the mission did not require abort capabilities. Exploration Flight Test 1 provides critical data that enable engineering to improve Orion's design and reduce risk for the astronauts it will protect as NASA continues to move forward on its human journey to Mars. The Exploration Flight Test 1 separation event occurred at six minutes and twenty seconds after liftoff. The separation of the Launch Abort System jettison occurs once Orion is safely through the most dynamic portion of the launch. This paper will present a brief overview of the objectives of the Launch Abort System during a nominal Orion flight. Secondly, the paper will present the performance of the Launch Abort System at it fulfilled those objectives. The lessons learned from Exploration Flight Test 1 and the other Flight Test Vehicles will certainly

  5. HUBBLE SPIES HUGE CLUSTERS OF STARS FORMED

    Science.gov (United States)

    2002-01-01

    BY ANCIENT ENCOUNTER This stunningly beautiful image [right] taken with the NASA Hubble Space Telescope shows the heart of the prototypical starburst galaxy M82. The ongoing violent star formation due to an ancient encounter with its large galactic neighbor, M81, gives this galaxy its disturbed appearance. The smaller picture at upper left shows the entire galaxy. The image was taken in December 1994 by the Kitt Peak National Observatory's 0.9-meter telescope. Hubble's view is represented by the white outline in the center. In the Hubble image, taken by the Wide Field and Planetary Camera 2, the huge lanes of dust that crisscross M82's disk are another telltale sign of the flurry of star formation. Below the center and to the right, a strong galactic wind is spewing knotty filaments of hydrogen and nitrogen gas. More than 100 super star clusters -- very bright, compact groupings of about 100,000 stars -- are seen in this detailed Hubble picture as white dots sprinkled throughout M82's central region. The dark region just above the center of the picture is a huge dust cloud. A collaboration of European and American scientists used these clusters to date the ancient interaction between M82 and M81. About 600 million years ago, a region called 'M82 B' (the bright area just below and to the left of the central dust cloud) exploded with new stars. Scientists have discovered that this ancient starburst was triggered by the violent encounter with M81. M82 is a bright (eighth magnitude), nearby (12 million light-years from Earth) galaxy in the constellation Ursa Major (the Great Bear). The Hubble picture was taken Sept. 15, 1997. The natural-color composite was constructed from three Wide Field and Planetary Camera 2 exposures, which were combined in chromatic order: 4,250 seconds through a blue filter (428 nm); 2,800 seconds through a green filter (520 nm); and 2,200 seconds through a red (820 nm) filter. Credits for Hubble image: NASA, ESA, R. de Grijs (Institute of

  6. Planetary nebulae abundances and stellar evolution

    CERN Document Server

    Pottasch, S R

    2006-01-01

    A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are the same as HII regions and early type star abundance gradients. The abundance of these elements predicted from these gradients at the distance of the Sun from the center are exactly the solar abundance. Sulfur is the exception to this; the reason for this is discussed. The higher solar neon abundance is confirmed; this is discussed in terms of the results of helioseismology. Evidence is presented for oxygen destruction via ON cycling having occurred in the progenitors of four planetary nebulae with bilobal structure. These progenitor stars had a high mass, probably greater than 5 solar masses. This is deduced from the high values of He/H and N/H found in these nebulae. Formation of nitrogen, helium and carbon are discussed. The high mass progenitors which showed oxygen de...

  7. Abundances of planetary nebula NGC2392

    NARCIS (Netherlands)

    Pottasch, S. R.; Bernard-Salas, J.; Roellig, T. L.

    The spectra of the planetary nebula NGC2392 is reanalysed using spectral measurements made in the mid-infrared with the Spitzer Space Telescope. The aim is to determine the chemical composition of this object. We also make use of IUE and ground based spectra. Abundances determined from the

  8. Argon and neon in Galactic nebulae

    Science.gov (United States)

    Simpson, Janet P.; Bregman, Jesse D.; Dinerstein, H. L.; Lester, Dan F.; Rank, David M.; Witteborn, F. C.; Wooden, D. H.

    1995-01-01

    KAO observations of the 6.98 micron line of (Ar II), and KAO and ground-based observations of the 8.99 micron line of (Ar III) and the 12.8 micron line of (Ne II) are presented for a number of Galactic H II regions and planetary nebulae.

  9. On the possible wind nebula of magnetar Swift J1834.9-0846: a magnetism-powered synchrotron nebula

    CERN Document Server

    Tong, H

    2016-01-01

    Recently, the magnetar Swift J1834.9$-$0846 is reported to have a possible wind nebula. It is shown that both the magnetar and its wind nebula are understandable in the wind braking scenario. The magnetar's rotational energy loss rate is not enough. The required particle luminosity should be about $10^{36} \\,\\rm erg \\,s^{-1}$ to $10^{38} \\,\\rm erg \\,s^{-1}$. It is obtained in three different approaches: considering wind braking of Swift J1834.9$-$0846; the spectral and spatial observations of the wind nebula; and an empirical upper bound on wind nebula X-ray luminosity. The nebula magnetic field is be about $10^{-4} \\,\\rm G$. The possible wind nebula of Swift J1834.9$-$0846 should be a magnetar wind nebula. It is powered by the magnetic energy release of the magnetar.

  10. On the possible wind nebula of magnetar Swift J1834.9–0846: a magnetism-powered synchrotron nebula

    Science.gov (United States)

    Tong, Hao

    2016-09-01

    Recently, the magnetar Swift J1834.9–0846 has been reported to have a possible wind nebula. It is shown that both the magnetar and its wind nebula are understandable in the wind braking scenario. The magnetar's rotational energy loss rate is not enough to power the particle luminosity. The required particle luminosity should be about 1036 erg s‑1 to 1038 erg s‑1. It is obtained in three different approaches: considering wind braking of Swift J1834.9–0846 the spectral and spatial observations of the wind nebula; and an empirical upper bound on wind nebula X-ray luminosity. The nebula magnetic field is about 10‑4 G. The possible wind nebula of Swift J1834.9–0846 should be a magnetar wind nebula. It is powered by the magnetic energy released from the magnetar.

  11. Delivering Hubble Discoveries to the Classroom

    Science.gov (United States)

    Eisenhamer, B.; Villard, R.; Weaver, D.; Cordes, K.; Knisely, L.

    2013-04-01

    Today's classrooms are significantly influenced by current news events, delivered instantly into the classroom via the Internet. Educators are challenged daily to transform these events into student learning opportunities. In the case of space science, current news events may be the only chance for educators and students to explore the marvels of the Universe. Inspired by these circumstances, the education and news teams developed the Star Witness News science content reading series. These online news stories (also available in downloadable PDF format) mirror the content of Hubble press releases and are designed for upper elementary and middle school level readers to enjoy. Educators can use Star Witness News stories to reinforce students' reading skills while exposing students to the latest Hubble discoveries.

  12. Frames of most uniform Hubble flow

    CERN Document Server

    Kraljic, David

    2016-01-01

    It has been observed that the locally measured Hubble parameter converges quickest to the background value and the dipole structure of the velocity field is smallest in the reference frame of the Local Group of galaxies. We study the statistical properties of Lorentz boosts with respect to the Cosmic Microwave Background frame which make the Hubble flow look most uniform around a particular observer. We use a very large N-Body simulation to extract the dependence of the boost velocities on the local environment such as underdensities, overdensities, and bulk flows. We find that the observation is not unexpected if we are located in an underdensity, which is indeed the case for our position in the universe. The amplitude of the measured boost velocity for our location is consistent with the expectation in the standard cosmology.

  13. Hubble parameter data constraints on dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yun, E-mail: chenyun@mail.bnu.edu.cn [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States); Ratra, Bharat, E-mail: ratra@phys.ksu.edu [Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506 (United States)

    2011-09-20

    We use Hubble parameter versus redshift data from Stern et al. (2010) and Gaztanaga et al. (2009) to place constraints on model parameters of constant and time-evolving dark energy cosmological models. These constraints are consistent with (through not as restrictive as) those derived from supernova Type Ia magnitude-redshift data. However, they are more restrictive than those derived from galaxy cluster angular diameter distance, and comparable with those from gamma-ray burst and lookback time data. A joint analysis of the Hubble parameter data with more restrictive baryon acoustic oscillation peak length scale and supernova Type Ia apparent magnitude data favors a spatially-flat cosmological model currently dominated by a time-independent cosmological constant but does not exclude time-varying dark energy.

  14. A BUTTERFLY-SHAPED 'PAPILLON' NEBULA YIELDS SECRETS OF MASSIVE STAR BIRTH

    Science.gov (United States)

    2002-01-01

    A NASA Hubble Space Telescope view of a turbulent cauldron of starbirth, called N159, taking place 170,000 light-years away in our satellite galaxy, the Large Magellanic Cloud (LMC). Torrential stellar winds from hot newborn massive stars within the nebula sculpt ridges, arcs, and filaments in the vast cloud, which is over 150 light-years across. A rare type of compact ionized 'blob' is resolved for the first time to be a butterfly-shaped or 'Papillon' (French for 'butterfly') nebula, buried in the center of the maelstrom of glowing gases and dark dust. The unprecedented details of the structure of the Papillon, itself less than 2 light-years in size (about 2 arcseconds in the sky), are seen in the inset. A possible explanation of this bipolar shape is the outflow of gas from massive stars (over 10 times the mass of our sun) hidden in the central absorption zone. Such stars are so hot that their radiation pressure halts the infall of gas and directs it away from the stars in two opposite directions. Presumably, a dense equatorial disk formed by matter still trying to fall in onto the stars focuses the outstreaming matter into the bipolar directions. This observation is part of a search for young massive stars in the LMC. Rare are the cases where we can see massive stars so early after their birth. The red in this true-color image is from the emission of hydrogen and the yellow from high excitation ionized oxygen. The picture was taken on September 5, 1998 with the Wide Field Planetary Camera 2. The Hubble observations of the Papillon nebula were conducted by the European astronomers Mohammad Heydari-Malayeri (Paris Observatory, France) and co-investigators Michael Rosa (Space Telescope-European Coordinating Facility, European Southern Observatory, Germany), Vassilis Charmandaris (Paris Observatory), Lise Deharveng (Marseille Observatory, France), and Hans Zinnecker (Astrophysical Institute, Potsdam, Germany). Their work is submitted for publication in the European

  15. A BUTTERFLY-SHAPED 'PAPILLON' NEBULA YIELDS SECRETS OF MASSIVE STAR BIRTH

    Science.gov (United States)

    2002-01-01

    A NASA Hubble Space Telescope view of a turbulent cauldron of starbirth, called N159, taking place 170,000 light-years away in our satellite galaxy, the Large Magellanic Cloud (LMC). Torrential stellar winds from hot newborn massive stars within the nebula sculpt ridges, arcs, and filaments in the vast cloud, which is over 150 light-years across. A rare type of compact ionized 'blob' is resolved for the first time to be a butterfly-shaped or 'Papillon' (French for 'butterfly') nebula, buried in the center of the maelstrom of glowing gases and dark dust. The unprecedented details of the structure of the Papillon, itself less than 2 light-years in size (about 2 arcseconds in the sky), are seen in the inset. A possible explanation of this bipolar shape is the outflow of gas from massive stars (over 10 times the mass of our sun) hidden in the central absorption zone. Such stars are so hot that their radiation pressure halts the infall of gas and directs it away from the stars in two opposite directions. Presumably, a dense equatorial disk formed by matter still trying to fall in onto the stars focuses the outstreaming matter into the bipolar directions. This observation is part of a search for young massive stars in the LMC. Rare are the cases where we can see massive stars so early after their birth. The red in this true-color image is from the emission of hydrogen and the yellow from high excitation ionized oxygen. The picture was taken on September 5, 1998 with the Wide Field Planetary Camera 2. The Hubble observations of the Papillon nebula were conducted by the European astronomers Mohammad Heydari-Malayeri (Paris Observatory, France) and co-investigators Michael Rosa (Space Telescope-European Coordinating Facility, European Southern Observatory, Germany), Vassilis Charmandaris (Paris Observatory), Lise Deharveng (Marseille Observatory, France), and Hans Zinnecker (Astrophysical Institute, Potsdam, Germany). Their work is submitted for publication in the European

  16. Hubble space telescope onboard battery performance

    Science.gov (United States)

    Rao, Gopalakrishna M.; Wajsgras, Harry; Vaidyanathan, Hari; Armontrout, Jon D.

    1996-01-01

    The performance of six 88 Ah Nickel-Hydrogen (Ni-H2) batteries that are used onboard in the Hubble Space Telescope (Flight Spare Module (FSM) and Flight Module 2 (FM2)) is discussed. These batteries have 22 series cells per battery and a common bus that would enable them to operate at a common voltage. It is launched on April 24, 1990. This paper reviews: the cell design, battery specification, system constraints, operating parameters, onboard battery management, and battery performance.

  17. Cosmic Supernova Rates and the Hubble Sequence

    CERN Document Server

    Calura, F

    2006-01-01

    We compute the type Ia, Ib/c and II supernova (SN) rates as functions of the cosmic time for galaxies of different morphological types. We use four different chemical evolution models, each one reproducing the features of a particular morphological type: E/S0, S0a/b, Sbc/d and Irr galaxies. We essentially describe the Hubble sequence by means of decreasing efficiency of star formation and increasing infall timescale. These models are used to study the evolution of the SN rates per unit luminosity and per unit mass as functions of cosmic time and as functions of the Hubble type. Our results indicate that: (i) the observed increase of the SN rate per unit luminosity and unit mass from early to late galaxy types is accounted for by our models. Our explanation of this effect is related to the fact that the latest Hubble types have the highest star formation rate per unit mass; (ii) By adopting a Scalo (1986) initial mass function in spiral disks, we find that massive single stars ending their lives as Wolf-Rayet ...

  18. IRAM 30 m large scale survey of {sup 12}CO(2-1) and {sup 13}CO(2-1) emission in the Orion molecular cloud

    Energy Technology Data Exchange (ETDEWEB)

    Berné, O.; Cernicharo, J. [Centro de Astrobiologá (CSIC/INTA), Ctra. de Torrejón a Ajalvir, km 4, E-28850, Torrejón de Ardoz, Madrid (Spain); Marcelino, N., E-mail: olivier.berne@irap.omp.eu [NRAO, 520 Edgemont Road, Charlottesville, VA 22902 (United States)

    2014-11-01

    Using the IRAM 30 m telescope, we have surveyed a 1 × 0.°8 part of the Orion molecular cloud in the {sup 12}CO and {sup 13}CO (2-1) lines with a maximal spatial resolution of ∼11'' and spectral resolution of ∼0.4 km s{sup –1}. The cloud appears filamentary, clumpy, and with a complex kinematical structure. We derive an estimated mass of the cloud of 7700 M {sub ☉} (half of which is found in regions with visual extinctions A{sub V} below ∼10) and a dynamical age for the nebula of the order of 0.2 Myr. The energy balance suggests that magnetic fields play an important role in supporting the cloud, at large and small scales. According to our analysis, the turbulent kinetic energy in the molecular gas due to outflows is comparable to turbulent kinetic energy resulting from the interaction of the cloud with the H II region. This latter feedback appears negative, i.e., the triggering of star formation by the H II region is inefficient in Orion. The reduced data as well as additional products such as the column density map are made available online (http://userpages.irap.omp.eu/∼oberne/Olivier{sub B}erne/Data).

  19. Herschel observations of EXtra-Ordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey Toward Orion KL I. Methods

    CERN Document Server

    Crockett, Nathan R; Neill, Justin L; Favre, Cécile; Schilke, Peter; Lis, Dariusz C; Bell, Tom A; Blake, Geoffrey; Cernicharo, José; Emprechtinger, Martin; Esplugues, Gisela B; Gupta, Harshal; Kleshcheva, Maria; Lord, Steven; Marcelino, Nuria; McGuire, Brett A; Pearson, John; Phillips, Thomas G; Plume, Rene; van der Tak, Floris; Tercero, Belén; Yu, Shanshan

    2014-01-01

    We present a comprehensive analysis of a broad band spectral line survey of the Orion Kleinmann-Low nebula (Orion KL), one of the most chemically rich regions in the Galaxy, using the HIFI instrument on board the Herschel Space Observatory. This survey spans a frequency range from 480 to 1907 GHz at a resolution of 1.1 MHz. These observations thus encompass the largest spectral coverage ever obtained toward this high-mass star-forming region in the sub-mm with high spectral resolution, and include frequencies $>$ 1 THz where the Earth's atmosphere prevents observations from the ground. In all, we detect emission from 39 molecules (79 isotopologues). Combining this dataset with ground based mm spectroscopy obtained with the IRAM 30 m telescope, we model the molecular emission from the mm to the far-IR using the XCLASS program which assumes local thermodynamic equilibrium (LTE). Several molecules are also modeled with the MADEX non-LTE code. Because of the wide frequency coverage, our models are constrained by ...

  20. Herschel observations of Extra-Ordinary Sources: H2S as a Probe of Dense Gas and Possibly Hidden Luminosity Toward the Orion KL Hot Core

    CERN Document Server

    Crockett, N R; Neill, J L; Black, J H; Blake, G A; Kleshcheva, M

    2014-01-01

    We present Herschel/HIFI observations of the light hydride H$_{2}$S obtained from the full spectral scan of the Orion Kleinmann-Low nebula (Orion KL) taken as part of the HEXOS GT key program. In total, we observe 52, 24, and 8 unblended or slightly blended features from H$_{2}$$^{32}$S, H$_{2}$$^{34}$S, and H$_{2}$$^{33}$S, respectively. We only analyze emission from the so called hot core, but emission from the plateau, extended ridge, and/or compact ridge are also detected. Rotation diagrams for ortho and para H$_{2}$S follow straight lines given the uncertainties and yield T$_{\\rm rot}$=141$\\pm$12 K. This indicates H$_{2}$S is in LTE and is well characterized by a single kinetic temperature or an intense far-IR radiation field is redistributing the population to produce the observed trend. We argue the latter scenario is more probable and find that the most highly excited states (E$_{\\rm up}$>1000 K) are likely populated primarily by radiation pumping. We derive an H$_{2}$$^{32}$S column density, N$_{\\rm ...

  1. IRAM-30m large scale survey of $^{12}$CO(2-1) and $^{13}$CO(2-1) emission in the Orion molecular cloud

    CERN Document Server

    Berne, Olivier; Cernicharo, Jose

    2014-01-01

    Using the IRAM 30m telescope we have surveyed a $1\\times0.8^{\\circ}$ part of the Orion molecular cloud in the $^{12}$CO and $^{13}$CO (2-1) lines with a maximal spatial resolution of $\\sim$11" and spectral resolution of $\\sim$ 0.4 km~s$^{-1}$. The cloud appears filamentary, clumpy and with a complex kinematical structure. We derive an estimated mass of the cloud of 7700 M$_{\\text{Sun}}$ (half of which is found in regions with visual extinctions $A_V$ below $\\sim$10) and a dynamical age for the nebula of the order of 0.2 Myrs. The energy balance suggests that magnetic fields play an important role in supporting the cloud, at large and small scales. According to our analysis, the turbulent kinetic energy in the molecular gas due to outflows is comparable to turbulent kinetic energy resulting from the interaction of the cloud with the HII region. This latter feedback appears negative, i.e. the triggering of star formation by the HII region is inefficient in Orion. The reduced data as well as additional products ...

  2. THE SPITZER SPACE TELESCOPE SURVEY OF THE ORION A AND B MOLECULAR CLOUDS. I. A CENSUS OF DUSTY YOUNG STELLAR OBJECTS AND A STUDY OF THEIR MID-INFRARED VARIABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Megeath, S. T.; Kryukova, E. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43560 (United States); Gutermuth, R. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Muzerolle, J. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Flaherty, K. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Hora, J. L.; Myers, P. C.; Fazio, G. G. [Harvard Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Allen, L. E. [National Optical Astronomical Observatory, Tucson, AZ 85719 (United States); Hartmann, L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Pipher, J. L. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Stauffer, J. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Young, E. T., E-mail: megeath@physics.utoledo.edu [SOFIA-Universities Space Research Association, NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2012-12-01

    We present a survey of the Orion A and B molecular clouds undertaken with the IRAC and MIPS instruments on board Spitzer. In total, five distinct fields were mapped, covering 9 deg{sup 2} in five mid-IR bands spanning 3-24 {mu}m. The survey includes the Orion Nebula Cluster, the Lynds 1641, 1630, and 1622 dark clouds, and the NGC 2023, 2024, 2068, and 2071 nebulae. These data are merged with the Two Micron All Sky Survey point source catalog to generate a catalog of eight-band photometry. We identify 3479 dusty young stellar objects (YSOs) in the Orion molecular clouds by searching for point sources with mid-IR colors indicative of reprocessed light from dusty disks or infalling envelopes. The YSOs are subsequently classified on the basis of their mid-IR colors and their spatial distributions are presented. We classify 2991 of the YSOs as pre-main-sequence stars with disks and 488 as likely protostars. Most of the sources were observed with IRAC in two to three epochs over six months; we search for variability between the epochs by looking for correlated variability in the 3.6 and 4.5 {mu}m bands. We find that 50% of the dusty YSOs show variability. The variations are typically small ({approx}0.2 mag) with the protostars showing a higher incidence of variability and larger variations. The observed correlations between the 3.6, 4.5, 5.8, and 8 {mu}m variability suggests that we are observing variations in the heating of the inner disk due to changes in the accretion luminosity or rotating accretion hot spots.

  3. The Spitzer Space Telescope Survey of the Orion A and B Molecular Clouds. I. A Census of Dusty Young Stellar Objects and a Study of Their Mid-infrared Variability

    Science.gov (United States)

    Megeath, S. T.; Gutermuth, R.; Muzerolle, J.; Kryukova, E.; Flaherty, K.; Hora, J. L.; Allen, L. E.; Hartmann, L.; Myers, P. C.; Pipher, J. L.; Stauffer, J.; Young, E. T.; Fazio, G. G.

    2012-12-01

    We present a survey of the Orion A and B molecular clouds undertaken with the IRAC and MIPS instruments on board Spitzer. In total, five distinct fields were mapped, covering 9 deg2 in five mid-IR bands spanning 3-24 μm. The survey includes the Orion Nebula Cluster, the Lynds 1641, 1630, and 1622 dark clouds, and the NGC 2023, 2024, 2068, and 2071 nebulae. These data are merged with the Two Micron All Sky Survey point source catalog to generate a catalog of eight-band photometry. We identify 3479 dusty young stellar objects (YSOs) in the Orion molecular clouds by searching for point sources with mid-IR colors indicative of reprocessed light from dusty disks or infalling envelopes. The YSOs are subsequently classified on the basis of their mid-IR colors and their spatial distributions are presented. We classify 2991 of the YSOs as pre-main-sequence stars with disks and 488 as likely protostars. Most of the sources were observed with IRAC in two to three epochs over six months; we search for variability between the epochs by looking for correlated variability in the 3.6 and 4.5 μm bands. We find that 50% of the dusty YSOs show variability. The variations are typically small (~0.2 mag) with the protostars showing a higher incidence of variability and larger variations. The observed correlations between the 3.6, 4.5, 5.8, and 8 μm variability suggests that we are observing variations in the heating of the inner disk due to changes in the accretion luminosity or rotating accretion hot spots.

  4. ALMA Observations of Orion Source I at 350 and 660 GHz

    Science.gov (United States)

    Plambeck, R. L.; Wright, M. C. H.

    2016-12-01

    Orion Source I (“SrcI”) is the protostar at the center of the Kleinmann-Low Nebula. ALMA observations of SrcI with 0.″2 angular resolution were made at 350 and 660 GHz to search for the H26α and H21α hydrogen recombination lines and to measure the continuum flux densities. The recombination lines were not detected, ruling out the possibility that SrcI is a hypercompact H ii region. The deconvolved size of the continuum source is approximately 0.″23 × 0.″07 (˜100 × 30 au); it is interpreted as a disk viewed almost edge-on. Optically thick thermal emission from ˜500 K dust is the most plausible source of the continuum, even at frequencies as low as 43 GHz; the disk mass is most likely in the range 0.02-0.2 {M}⊙ . A rich spectrum of molecular lines is detected, mostly from sulfur- and silicon-rich molecules like SO, SO2, and SiS, but also including vibrationally excited CO and several unidentified transitions. Lines with upper energy levels {E}{{U}}\\gt 500 K appear in emission and are symmetric about the source’s LSR velocity of 5 {km} {{{s}}}-1, while lines with {E}{{U}}\\lt 500 K appear as blueshifted absorption features against the continuum, indicating that they originate in outflowing gas. The emission lines exhibit a velocity gradient along the major axis of the disk that is consistent with rotation around a 5-7 {M}⊙ central object. The relatively low mass of SrcI and the existence of a 100 au disk around it are difficult to reconcile with the model in which SrcI and the nearby Becklin-Neugebauer Object were ejected from a multiple system 500 years ago.

  5. Stellar models simulating the disk-locking mechanism and the evolutionary history of the Orion Nebula cluster and NGC2264

    CERN Document Server

    Landin, N R; Vaz, L P R; Alencar, S H P

    2015-01-01

    Rotational evolution in young stars is described by pMS evolutionary tracks including rotation, conservation of angular momentum (AM), and simulations of disk-locking (DL). By assuming that DL is the regulation mechanism for the stellar angular velocity during the early stages of pMS, we use our models and observational data to constrain disk lifetimes (Tdisk) of a sample of low-mass stars in the ONC and NGC2264. The period distributions of the ONC and NGC2264 are bimodal and depend on the stellar mass. To follow the rotational evolution of these two clusters' stars, we generated some sets of evolutionary tracks. We assumed that the evolution of fast rotators can be modeled by considering conservation of AM during all stages and of moderate rotators by considering conservation of angular velocity during the first stages of evolution. With these models we estimate a mass and an age for all stars. For the ONC, we assume that the secondary peak in the period distribution is due to high-mass objects locked in the...

  6. The spectral type of CHS7797 - an intriguing very low mass periodic variable in the Orion Nebula Cluster

    CERN Document Server

    Rodriguez-Ledesma, M V; Pintado, O; Boudreault, S; Hessman, F; Herbst, W

    2013-01-01

    We present the spectroscopic characterization of the unusual high-amplitude very low mass pre-main-sequence periodic variable CHS7797. This study is based on optical medium-resolution (R=2200) spectroscopy in the 6450-8600 A range, carried out with GMOS-GEMINI-S in March 2011. Observations of CHS7797 have been carried out at two distinct phases of the 17.8d period, namely at maximum and four days before maximum. Four different spectral indices were used for the spectral classification at these two phases, all of them well-suited for spectral classification of young and obscured late M dwarfs. In addition, the gravity-sensitive NaI (8183/8195 A) and KI (7665/7699 A) doublet lines were used to confirm the young age of CHS7797. From the spectrum obtained at maximum light we derived a spectral type (SpT) of M6.05, while for the spectrum taken four days before maximum the derived SpT is M5.75. The derived SpTs confirm that CHS7797 has a mass in the stellar-substellar boundary mass range. In addition, the small dif...

  7. Orion Handling Qualities During ISS Proximity Operations and Docking

    Science.gov (United States)

    Stephens, John-Paul; Vos, Gordon A.; Bilimoria, Karl D.; Mueller, Eric R.; Brazzel, Jack; Spehar, Pete

    2011-01-01

    NASA's Orion spacecraft is designed to autonomously rendezvous and dock with many vehicles including the International Space Station. However, the crew is able to assume manual control of the vehicle s attitude and flight path. In these instances, Orion must meet handling qualities requirements established by NASA. Two handling qualities assessments were conducted at the Johnson Space Center to evaluate preliminary designs of the vehicle using a six degree of freedom, high-fidelity guidance, navigation, and control simulation. The first assessed Orion s handling qualities during the last 20 ft before docking, and included both steady and oscillatory motions of the docking target. The second focused on manual acquisition of the docking axis during the proximity operations phase and subsequent station-keeping. Cooper-Harper handling qualities ratings, workload ratings and comments were provided by 10 evaluation pilots for the docking study and 5 evaluation pilots for the proximity operations study. For the docking task, both cases received 90% Level 1 (satisfactory) handling qualities ratings, exceeding NASA s requirement. All ratings for the ProxOps task were Level 1. These evaluations indicate that Orion is on course to meet NASA's handling quality requirements for ProxOps and docking.

  8. Designing Struts for the Low-Fidelity Orion Cockpit Mockup

    Science.gov (United States)

    Lucienne, Runa A.

    2009-01-01

    The objective of the project was to design and construct nine struts to be installed in the low-fidelity Orion cockpit mockup (Rev F; located at NASA s Johnson Space Center in Houston, TX) as simplified representations of the existing flight designed struts designed by engineers at Lockheed Martin (the primary contractor of the Orion). The project design included: researching the existing flight designs, brainstorming design upgrades, developing three unrelated three-dimensional (3D) strut designs using Pro/Engineer Wildfire 3.0, choosing the best fit design, locating materials and their sources, implementing the chosen design, and making design modifications. The project resulted in making simple modifications to the existing struts used in the last Orion cockpit mockup. The project is relevant to NASA, because upgrades to the low-fidelity Orion cockpit mockup progresses NASA s goals of developing and testing a new spacecraft, conducting the spacecraft's first crewed mission by 2015, returning to the moon by 2020, and exploring Mars and other planets in the future.

  9. Apollo 16 Lunar Module 'Orion' at the Descartes landing site

    Science.gov (United States)

    1972-01-01

    The Apollo 16 Lunar Module 'Orion' is part of the lunar scene at the Descartes landing site, as seen in the reproduction taken from a color television transmission made by the color TV camera mounted on the Lunar Roving Vehicle. Note the U.S. flag deployed on the left. This picture was made during the second Apollo 16 extravehicular activity (EVA-2).

  10. Rotational periods of solar-mass young stars in Orion

    NARCIS (Netherlands)

    Marilli, E.; Frasca, A.; Covino, E.; Alcalá, J.M.; Catalano, S.; Fernández, M.; Arellano Ferro, A.; Rubio Herrera, E.A.; Spezzi, L.

    2007-01-01

    Context: The evolution of the angular momentum in young low-mass stars is still a debated issue. The stars presented here were discovered as X-ray sources in the ROSAT All-Sky Survey (RASS) of the Orion complex and subsequently optically identified thanks to both low and high resolution spectroscopy

  11. On the Longicorn genus Orion, Guér

    NARCIS (Netherlands)

    Ritsema Cz., C.

    1889-01-01

    In the „Genera des Coléoptères” (VIII, p. 300) Lacordaire, in accordance with Guérin’s views, ascribes to the female of Orion patagonus Guér. a prothorax which is more strongly rugose than in the male and the callosities of which are less numerous and but little conspicuous. Now the Leyden Museum po

  12. 'Peony Nebula' Star Settles for Silver Medal

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Poster Version Movie If our galaxy, the Milky Way, were to host its own version of the Olympics, the title for the brightest known star would go to a massive star called Eta Carina. However, a new runner-up now the second-brightest star in our galaxy has been discovered in the galaxy's dusty and frenzied interior. This image from NASA's Spitzer Space Telescope shows the new silver medalist, circled in the inset above, in the central region of our Milky Way. Dubbed the 'Peony nebula' star, this blazing ball of gas shines with the equivalent light of 3.2 million suns. The reigning champ, Eta Carina, produces the equivalent of 4.7 million suns worth of light though astronomers say these estimates are uncertain, and it's possible that the Peony nebula star could be even brighter than Eta Carina. If the Peony star is so bright, why doesn't it stand out more in this view? The answer is dust. This star is located in a very dusty region jam packed with stars. In fact, there could be other super bright stars still hidden deep in the stellar crowd. Spitzer's infrared eyes allowed it to pierce the dust and assess the Peony nebula star's true brightness. Likewise, infrared data from the European Southern Observatory's New Technology Telescope in Chile were integral in calculating the Peony nebula star's luminosity. The Peony nebula, which surrounds the Peony nebular star, is the reddish cloud of dust in and around the white circle. The movie begins by showing a stretch of the dusty and frenzied central region of our Milky Way galaxy. It then zooms in to reveal the 'Peony nebula' star the new second-brightest star in the Milky Way, discovered in part by NASA's Spitzer Space Telescope. This is a three-color composite showing infrared observations from two Spitzer instruments. Blue represents 3.6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array

  13. Birth and early evolution of a planetary nebula

    CERN Document Server

    Bobrowsky, M; Parthasarathy, M; García-Lario, P

    1998-01-01

    The final expulsion of gas by a star as it forms a planetary nebula --- the ionized shell of gas often observed surrounding a young white dwarf --- is one of the most poorly understood stages of stellar evolution. Such nebulae form extremely rapidly (about 100 years for the ionization) and so the formation process is inherently difficult to observe. Particularly puzzling is how a spherical star can produce a highly asymmetric nebula with collimated outflows. Here we report optical observations of the Stingray Nebula which has become an ionized planetary nebula within the past few decades. We find that the collimated outflows are already evident, and we have identified the nebular structure that focuses the outflows. We have also found a companion star, reinforcing previous suspicions that binary companions play an important role in shaping planetary nebulae and changing the direction of successive outflows.

  14. FACT. Energy spectrum of the Crab Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Temme, Fabian; Einecke, Sabrina; Buss, Jens [TU Dortmund, Experimental Physics 5, Otto-Hahn-Str.4, 44221 Dortmund (Germany); Collaboration: FACT-Collaboration

    2016-07-01

    The First G-APD Cherenkov Telescope is the first Imaging Air Cherenkov Telescope which uses silicon photon detectors (G-APDs aka SiPM) as photo sensors. With more than four years of operation, FACT proved an application of SiPMs is suitable for the field of ground-based gamma-ray astronomy. Due to the stable flux at TeV energies, the Crab Nebula is handled as a ''standard candle'' in Cherenkov astronomy. The analysis of its energy spectrum and comparison with other experiments, allows to evaluate the performance of FACT. A modern analysis chain, based on data stream handling and multivariate analysis methods was developed in close cooperation with the department of computer science at the TU Dortmund. In this talk, this analysis chain and its application are presented. Further to this, results, including the energy spectrum of the Crab Nebula, measured with FACT, are shown.

  15. Magnetic field in the primitive solar nebula

    Science.gov (United States)

    Levy, E. H.

    1978-01-01

    Carbonaceous chondrites have apparently been magnetized in their early history in magnetic fields with intensities of 0.1 to 10 G, but the origin of the magnetizing field has remained obscured. It is suggested that the magnetic field recorded in the remanence of carbonaceous chondrites may have been produced by a self-excited hydromagnetic dynamo in the gaseous preplanetary nebula from which the solar system is thought to have formed. Recently computed models for the evolution of the preplanetary nebula, consisting of turbulent and differentially rotating gaseous disks with characteristic radial scales of several AU, are used to demonstrate the feasibility of this hypothesis. The maximum field intensity that might be realized by the dynamo production process is estimated to be as high as 1 to 10 G, taking into account two dynamical mechanisms that limit the strength of the field (the Coriolis force and ambipolar diffusion).

  16. Interstellar molecules - Formation in solar nebulae

    Science.gov (United States)

    Anders, E.

    1973-01-01

    Herbig's (1970) hypothesis that solar nebulae might be the principal source of interstellar grains and molecules is investigated. The investigation includes the determination of physical and chemical conditions in the early solar system. The production of organic compounds in the solar nebula is studied, and the compounds in meteorites are compared with those obtained in Miller-Urey and Fischer-Tropsch-type (FTT) reactions, taking into consideration aliphatic hydrocarbons, aromatic hydrocarbons, purines, pyrimidines, amino acids, porphyrins, and aspects of carbon-isotope fractionation. It is found that FTT reactions account reasonably well for all well-established features of organic matter in meteorites investigated. The distribution of compounds produced by FTT reactions is compared with the distribution of interstellar molecules. Biological implications of the results are considered.

  17. Star Formation in the Eagle Nebula

    CERN Document Server

    Oliveira, Joana M

    2008-01-01

    M16 (the Eagle Nebula) is a striking star forming region, with a complex morphology of gas and dust sculpted by the massive stars in NGC 6611. Detailed studies of the famous ``elephant trunks'' dramatically increased our understanding of the massive star feedback into the parent molecular cloud. A rich young stellar population (2 - 3 Myr) has been identified, from massive O-stars down to substellar masses. Deep into the remnant molecular material, embedded protostars, Herbig-Haro objects and maser sources bear evidence of ongoing star formation in the nebula, possibly triggered by the massive cluster members. M 16 is a excellent template for the study of star formation under the hostile environment created by massive O-stars. This review aims at providing an observational overview not only of the young stellar population but also of the gas remnant of the star formation process.

  18. The nebulae around LBVs: a multiwavelength approach

    CERN Document Server

    Umana, Grazia; Trigilio, Corrado; Leto, Paolo; Hora, Joseph L; Fazio, Giovanni

    2010-01-01

    We present first results of our study of a sample of Galactic LBV, aimed to contribute to a better understanding of the LBV phenomenon, by recovering the mass-loss history of the central object from the analysis of its associated nebula. Mass-loss properties have been derived by a synergistic use of different techniques, at different wavelengths, to obtain high-resolution, multi-wavelength maps, tracing the different emitting components coexisting in the stellar ejecta: the ionized/neutral gas and the dust. Evidence for asymmetric mass-loss and observational evidence of possible mutual interaction between gas and dust components have been observed by the comparison of mid-IR (Spitzer/IRAC, VLT/VISIR) and radio (VLA) images of the nebulae, while important information on the gas and dust composition have been derived from Spitzer/IRS spectra.

  19. Ring Nebulae: Tracers of the CNO Nucleosynthesis

    CERN Document Server

    Mesa-Delgado, A; García-Rojas, J

    2015-01-01

    Preliminary results are presented from spectroscopic data in the optical range of the Galactic ring nebulae NGC 6888, G2:4+1:4, RCW 58 and Sh2-308. Deep observations with long exposure times were carried out at the 6.5m Clay Telescope and at the 10.4m Gran Telescopio Canarias. In NGC 6888, recombination lines of C II, O II and N II are detected with signal-to-noise ratios higher than 8. The chemical content of NGC 6888 is discussed within the chemical enrichment predicted by evolution models of massive stars. For all nebulae, a forthcoming work will content in-depth details about observations, analysis and final results (Esteban et al. 2015, in prep.).

  20. The theory of pulsar winds and nebulae

    CERN Document Server

    Kirk, J G; Petri, J

    2007-01-01

    We review current theoretical ideas on pulsar winds and their surrounding nebulae. Relativistic MHD models of the wind of the aligned rotator, and of the striped wind, together with models of magnetic dissipation are discussed. It is shown that the observational signature of this dissipation is likely to be point-like, rather than extended, and that pulsed emission may be produced. The possible pulse shapes and polarisation properties are described. Particle acceleration at the termination shock of the wind is discussed, and it is argued that two distinct mechanisms must be operating, with the first-order Fermi mechanism producing the high-energy electrons (above 1 TeV) and either magnetic annihilation or resonant absorption of ion cyclotron waves responsible for the 100 MeV to 1 TeV electrons. Finally, MHD models of the morphology of the nebula are discussed and compared with observation.

  1. The type Ia supernovae and the Hubble's constant

    OpenAIRE

    2004-01-01

    The Hubble's constant is usually surmised to be a constant; but the experiments show a large spread and conflicting estimates. According to the plasma-redshift theory, the Hubble's constant varies with the plasma densities along the line of sight. It varies then slightly with the direction and the distance to a supernova and a galaxy. The relation between the magnitudes of type Ia supernovae and their observed redshifts results in an Hubble's constant with an average value in intergalactic sp...

  2. Discovery of New Faint Northern Galactic Planetary Nebulae

    CERN Document Server

    Acker, Agnes; Outters, Nicolas; Miszalski, Brent; Sabin, Laurence; Le Du, Pascal; Alves, Filipe

    2012-01-01

    We present the discovery of 6 nebular objects made by amateur astronomers. Four of these discoveries are clearly planetary nebulae (PNe), one is a possible PN, and another is a likely H II region. The bipolar nebula Ou4 presents the largest angular extent ever found : over one degree on the sky! We consider various scenarios that could explain such a nebula. Ou4 could be one of the nearest PNe known, though its possible PN nature will need confirmation.

  3. Observations of the thin filamentary nebula Simeiz 22

    Energy Technology Data Exchange (ETDEWEB)

    Lozinskaya, T.A.; Sitnik, T.G.; Toropova, M.S.; Klement' eva, A.Yu. (Moskovskij Gosudarstvennyj Univ. (USSR) Gosudarstvennyj Astronomicheskij Inst. ' ' GAISh' ' )

    1984-02-01

    The (N 2), (S 2) and (0 3) image-converter photographs of the rebula Simeiz 22 made through interfererce filters in the Cassegrain focus of the 125-cm reflector are presented. Detailed isophote systems in every line are obtained by photographic eguidepsitometry methods. Our narrow-bandrass photographs show variations in the nebula morphology, including the emission stratification typical of planetary nebulae. The origin of the nebula is discussed; some indirect arguments showing mass loss by the central star are presented.

  4. OPTICAL SPECTROSCOPY OF X-RAY-SELECTED YOUNG STARS IN THE CARINA NEBULA

    Energy Technology Data Exchange (ETDEWEB)

    Vaidya, Kaushar [Physics Department, Birla Institute of Technology and Science Pilani, Pilani 333031, Rajasthan (India); Chen, Wen-Ping; Lee, Hsu-Tai [Graduate Institute of Astronomy, National Central University, 300 Zhongda Road, Zhongli 32001, Taiwan (China)

    2015-12-15

    We present low-resolution optical spectra for 29 X-ray sources identified as either massive star candidates or low-mass pre-main-sequence (PMS) star candidates in the clusters Trumpler 16 and Trumpler 14 of the Carina Nebula. Spectra of two more objects (one with an X-ray counterpart, and one with no X-ray counterpart), not originally our targets, but found close (∼3″) to two of our targets, are presented as well. Twenty early-type stars, including an O8 star, seven B1–B2 stars, two B3 stars, a B5 star, and nine emission-line stars, are identified. Eleven T Tauri stars, including eight classical T Tauri stars (CTTSs) and three weak-lined T Tauri stars, are identified. The early-type stars in our sample are more reddened compared to the previously known OB stars of the region. The Chandra hardness ratios of our T Tauri stars are found to be consistent with the Chandra hardness ratios of T Tauri stars of the Orion Nebula Cluster. Most early-type stars are found to be nonvariable in X-ray emission, except the B2 star J104518.81–594217.9, the B3 star J104507.84–594134.0, and the Ae star J104424.76–594555.0, which are possible X-ray variables. J104452.20–594155.1, a CTTS, is among the brightest and the hardest X-ray sources in our sample, appears to be a variable, and shows a strong X-ray flare. The mean optical and near-infrared photometric variability in the V and K{sub s} bands, of all sources, is found to be ∼0.04 and 0.05 mag, respectively. The T Tauri stars show significantly larger mean variation, ∼0.1 mag, in the K{sub s} band. The addition of one O star and seven B1–B2 stars reported here contributes to an 11% increase of the known OB population in the observed field. The 11 T Tauri stars are the first ever confirmed low-mass PMS stars in the Carina Nebula region.

  5. Multiband observations of the Crab Nebula

    Science.gov (United States)

    Krassilchtchikov, A. M.; Bykov, A. M.; Castelletti, G. M.; Dubner, G. M.; Kargaltsev, O. Yu; Pavlov, G. G.

    2017-01-01

    Results of simultaneous imaging of the Crab Nebula in the radio (JVLA), optical (HST), and X-ray (Chandra) bands are presented. The images show a variety of small-scale structures, including wisps mainly located to the north-west of the pulsar and knots forming a ring-like structure associated with the termination shock of the pulsar wind. The locations of the structures in different bands do not coincide with each other.

  6. Pulsating Radio Sources near the Crab Nebula.

    Science.gov (United States)

    Staelin, D H; Reifenstein, E C

    1968-12-27

    Two new pulsating radio sources, designated NP 0527 and NP 0532, were found near the Crab Nebula and could be coincident with it. Both sources are sporadic, and no periodicities are evident. The pulse dispersions indicate that 1.58 +/- 0.03 and 1.74 +/- 0.02 x 10(20) electrons per square centimeter lie in the direction of NP 0527 and NP 0532, respectively.

  7. Planetary nebulae in the Small Magellanic Cloud

    Science.gov (United States)

    Ventura, P.; Stanghellini, L.; Di Criscienzo, M.; García-Hernández, D. A.; Dell'Agli, F.

    2016-08-01

    We analyse the planetary nebulae (PNe) population of the Small Magellanic Cloud (SMC), based on evolutionary models of stars with metallicities in the range 10-3 ≤ Z ≤ 4 × 10-3 and mass 0.9 M⊙ Magellanic Cloud is explained on the basis of the diverse star formation history and age-metallicity relation of the two galaxies. The implications of this study for some still highly debated points regarding the AGB evolution are also commented.

  8. High scale anisotropies in planetary nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Pascoli, G.

    1986-06-01

    We present a new classification of Planetary Nebulae (PN) grounded on their characteristic symmetries: bipolarity, ring shape, spiral structure, etc... The different anisotropic models (rotation of nucleus, binary progenitor intranebular magnetic field, nebular rotation, etc...) which have been lately proposed, are analysed and their explanatory power is tested with certain morphological criterious. The comparison with the other classifications (Acker, 1980; Kaler, 1978; Peimbert, 1978) reveals that the morphology has been insufficiently discussed in these latters.

  9. Orion Launch Abort System Performance on Exploration Flight Test 1

    Science.gov (United States)

    McCauley, R.; Davidson, J.; Gonzalez, Guillermo

    2015-01-01

    This paper will present an overview of the flight test objectives and performance of the Orion Launch Abort System during Exploration Flight Test-1. Exploration Flight Test-1, the first flight test of the Orion spacecraft, was managed and led by the Orion prime contractor, Lockheed Martin, and launched atop a United Launch Alliance Delta IV Heavy rocket. This flight test was a two-orbit, high-apogee, high-energy entry, low-inclination test mission used to validate and test systems critical to crew safety. This test included the first flight test of the Launch Abort System preforming Orion nominal flight mission critical objectives. NASA is currently designing and testing the Orion Multi-Purpose Crew Vehicle (MPCV). Orion will serve as NASA's new exploration vehicle to carry astronauts to deep space destinations and safely return them to earth. The Orion spacecraft is composed of four main elements: the Launch Abort System, the Crew Module, the Service Module, and the Spacecraft Adapter (Fig. 1). The Launch Abort System (LAS) provides two functions; during nominal launches, the LAS provides protection for the Crew Module from atmospheric loads and heating during first stage flight and during emergencies provides a reliable abort capability for aborts that occur within the atmosphere. The Orion Launch Abort System (LAS) consists of an Abort Motor to provide the abort separation from the Launch Vehicle, an Attitude Control Motor to provide attitude and rate control, and a Jettison Motor for crew module to LAS separation (Fig. 2). The jettison motor is used during a nominal launch to separate the LAS from the Launch Vehicle (LV) early in the flight of the second stage when it is no longer needed for aborts and at the end of an LAS abort sequence to enable deployment of the crew module's Landing Recovery System. The LAS also provides a Boost Protective Cover fairing that shields the crew module from debris and the aero-thermal environment during ascent. Although the

  10. 75 FR 66728 - Action Affecting Export Privileges; Orion Air, S.L. and Syrian Pearl Airlines: Orion Air, S.L...

    Science.gov (United States)

    2010-10-29

    ... Airlines: Orion Air, S.L., Canada Real de Merinas, 7 Edificio 5, 3'A, Eissenhower Business Center, 28042 Madrid, Spain; and Ad. de las Cortes Valencianas no 37, Esc. A Puerta 45 46015 Valencia, Spain; and... EAR. It is therefore ordered: First, that, Orion Air, S.L., Canada Real de Merinas, 7 Edificio 5,...

  11. Kinematics, turbulence and evolution of planetary nebulae

    CERN Document Server

    Gesicki, K; Zijlstra, A A; Gesicki, Krzysztof; Acker, Agnes; Zijlstra, Albert A.

    2003-01-01

    This paper discusses the location of a sample of planetary nebulae on the HR diagram. We determine the internal velocity fields of 14 planetary nebulae from high-resolution echelle spectroscopy, with the help of photoionization models. The mass averaged velocity is shown to be a robust, simple parameter describing the outflow. The expansion velocity and radius are used to define the dynamical age; together with the stellar temperature, this gives a measurement of the luminosity and core mass of the central star. The same technique is applied to other planetary nebulae with previously measured expansion velocities, giving a total sample of 73 objects. The objects cluster closely around the Schoenberner track of 0.61 M_sun, with a very narrow distribution of core masses. The masses are higher than found for local white dwarfs. The luminosities determined in this way tend to be higher by a factor of a few than those derived from the nebular luminosities. The discrepancy is highest for the hottest (most evolved) ...

  12. of Planetary Nebulae III. NGC 6781

    Directory of Open Access Journals (Sweden)

    Hugo E. Schwarz

    2006-01-01

    Full Text Available Continuing our series of papers on the three-dimensional (3D structures and accurate distances to Planetary Nebulae (PNe, we present our study of the planetary nebula NGC6781. For this object we construct a 3D photoionization model and, using the constraints provided by observational data from the literature we determine the detailed 3D structure of the nebula, the physical parameters of the ionizing source and the first precise distance. The procedure consists in simultaneously fitting all the observed emission line morphologies, integrated intensities and the two-dimensional (2D density map from the [SII] (sulfur II line ratios to the parameters generated by the model, and in an iterative way obtain the best fit for the central star parameters and the distance to NGC6781, obtaining values of 950±143 pc (parsec – astronomic distance unit and 385 LΘ (solar luminosity for the distance and luminosity of the central star respectively. Using theoretical evolutionary tracks of intermediate and low mass stars, we derive the mass of the central star of NGC6781 and its progenitor to be 0.60±0.03MΘ (solar mass and 1.5±0.5MΘ respectively.

  13. HOPS 136: An edge-on orion protostar near the end of envelope infall

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, William J.; Megeath, S. Thomas [Department of Physics and Astronomy, University of Toledo, Toledo, OH (United States); Tobin, John J. [National Radio Astronomy Observatory, Charlottesville, VA (United States); Hartmann, Lee; Kounkel, Marina [Department of Astronomy, University of Michigan, Ann Arbor, MI (United States); Stutz, Amelia M. [Max-Planck-Institut für Astronomie, Heidelberg (Germany); Poteet, Charles A. [New York Center for Astrobiology, Rensselaer Polytechnic Institute, Troy, NY (United States); Ali, Babar [NHSC/IPAC/Caltech, Pasadena, CA (United States); Osorio, Mayra [Instituto de Astrofísica de Andalucía, CSIC, Granada (Spain); Manoj, P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai (India); Remming, Ian [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL (United States); Stanke, Thomas [ESO, Garching bei München (Germany); Watson, Dan M., E-mail: wjfischer@gmail.com [Department of Physics and Astronomy, University of Rochester, Rochester, NY (United States)

    2014-02-01

    Edge-on protostars are valuable for understanding the disk and envelope properties of embedded young stellar objects, since the disk, envelope, and envelope cavities are all distinctly visible in resolved images and well constrained in modeling. Comparing Two Micron All Sky Survey, Wide-field Infrared Survey Explorer, Spitzer, Herschel, and APEX photometry and an IRAM limit from 1.2 to 1200 μm, Spitzer spectroscopy from 5 to 40 μm, and high-resolution Hubble imaging at 1.60 and 2.05 μm to radiative transfer modeling, we determine envelope and disk properties for the Class I protostar HOPS 136, an edge-on source in Orion's Lynds 1641 region. The source has a bolometric luminosity of 0.8 L {sub ☉}, a bolometric temperature of 170 K, and a ratio of submillimeter to bolometric luminosity of 0.8%. Via modeling, we find a total luminosity of 4.7 L {sub ☉} (larger than the observed luminosity due to extinction by the disk), an envelope mass of 0.06 M {sub ☉}, and a disk radius and mass of 450 AU and 0.002 M {sub ☉}. The stellar mass is highly uncertain but is estimated to fall between 0.4 and 0.5 M {sub ☉}. To reproduce the flux and wavelength of the near-infrared scattered-light peak in the spectral energy distribution, we require 5.4 × 10{sup –5} M {sub ☉} of gas and dust in each cavity. The disk has a large radius and a mass typical of more evolved T Tauri disks in spite of the significant remaining envelope. HOPS 136 appears to be a key link between the protostellar and optically revealed stages of star formation.

  14. The evolution of planetary nebulae VII. Modelling planetary nebulae of distant stellar systems

    CERN Document Server

    Schönberner, D; Sandin, C; Steffen, M

    2010-01-01

    By means of hydrodynamical models we do the first investigations of how the properties of planetary nebulae are affected by their metal content and what can be learned from spatially unresolved spectrograms of planetary nebulae in distant stellar systems. We computed a new series of 1D radiation-hydrodynamics planetary nebulae model sequences with central stars of 0.595 M_sun surrounded by initial envelope structures that differ only by their metal content. At selected phases along the evolutionary path, the hydrodynamic terms were switched off, allowing the models to relax for fixed radial structure and radiation field into their equilibrium state with respect to energy and ionisation. The analyses of the line spectra emitted from both the dynamical and static models enabled us to systematically study the influence of hydrodynamics as a function of metallicity and evolution. We also recomputed selected sequences already used in previous publications, but now with different metal abundances. These sequences w...

  15. A deep kinematic survey of planetary nebulae in the Andromeda Galaxy using the Planetary Nebula Spectrograph

    CERN Document Server

    Merrett, H R; Bridges, T J; Capaccioli, M; Carter, D; Coccato, L; Douglas, N G; Evans, N W; Freeman, K C; Gerhard, O; Halliday, C; Kuijken, K; Merrifield, M R; Napolitano, N R; Romanowsky, A J; Wilkinson, M I

    2006-01-01

    We present a catalogue of positions, magnitudes and velocities for 3300 emission-line objects found by the Planetary Nebula Spectrograph in a survey of the Andromeda Galaxy, M31. Of these objects, 2615 are found likely to be planetary nebulae (PNe) associated with M31. The survey area covers the whole of M31's disk out to a radius of 1.5 degrees. Beyond this radius, observations have been made along the major and minor axes, and the Northern Spur and Southern Stream regions. The calibrated data have been checked for internal consistency and compared with other catalogues. With the exception of the very central, high surface brightness region of M31, this survey is complete to a magnitude limit of m_5007~23.75, 3.5 magnitudes into the planetary nebula luminosity function.

  16. Hubble Deep Fever A faint galaxy diagnosis

    CERN Document Server

    Driver, S P

    1998-01-01

    The longstanding faint blue galaxy problem is gradually subsiding as a result of technological advancement, most notably from high-resolution Hubble Space Telescope imaging. In particular two categorical facts have recently been established, these are: 1) The excess faint blue galaxies are of irregular morphologies, and, 2) the majority of these irregulars occur at redshifts 1 2. Taking these facts together we favour a scenario where the faint blue excess is primarily due to the formation epoch of spiral systems via merging at redshifts 1 < z < 2. The final interpretation now awaits refinements in our understanding of the local galaxy population !

  17. Hubble Parameter in Bulk Viscous Cosmology

    CERN Document Server

    Tawfik, A; Wahba, M

    2009-01-01

    We discuss influences of bulk viscosity on the Early Universe, which is modeled by Friedmann-Robertson-Walker metric and Einstein field equations. We assume that the matter filling the isotropic and homogeneous background is relativistic viscous characterized by ultra-relativistic equations of state deduced from recent lattice QCD simulations. We obtain a set of complicated differential equations, for which we suggest approximate solutions for Hubble parameter $H$. We find that finite viscosity in Eckart and Israel-Stewart fluids would significantly modify our picture about the Early Universe.

  18. Hubble Parameter Corrected Interactions in Cosmology

    Directory of Open Access Journals (Sweden)

    J. Sadeghi

    2014-01-01

    character opening a room for different kinds of manipulations. In this paper we will consider a modification of an interaction Q, where we accept that interaction parameter b1 (order of unity in Q=3Hb1ρ is time dependent and presented as a linear function of Hubble parameter H of the form b0+btH, where b and b0 are constants. We consider two different models including modified Chaplygin gas and polytropic gas which have bulk viscosity. Then, we investigate problem numerically and analyze behavior of different cosmological parameters concerning fluids and behavior of the universe.

  19. STARING INTO THE WINDS OF DESTRUCTION: HST/NICMOS IMAGES OF THE PLANETARY NEBULA NGC 7027

    Science.gov (United States)

    2002-01-01

    The Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) has captured a glimpse of a brief stage in the burnout of NGC 7027, a medium-mass star like our sun. The infrared image (on the left) shows a young planetary nebula in a state of rapid transition. This image alone reveals important new information. When astronomers combine this photo with an earlier image taken in visible light, they have a more complete picture of the final stages of star life. NGC 7027 is going through spectacular death throes as it evolves into what astronomers call a 'planetary nebula.' The term planetary nebula came about not because of any real association with planets, but because in early telescopes these objects resembled the disks of planets. A star can become a planetary nebula after it depletes its nuclear fuel - hydrogen and helium - and begins puffing away layers of material. The material settles into a wind of gas and dust blowing away from the dying star. This NICMOS image captures the young planetary nebula in the middle of a very short evolutionary phase, lasting perhaps less than 1,000 years. During this phase, intense ultraviolet radiation from the central star lights up a region of gas surrounding it. (This gas is glowing brightly because it has been made very hot by the star's intense ultraviolet radiation.) Encircling this hot gas is a cloud of dust and cool molecular hydrogen gas that can only be seen by an infrared camera. The molecular gas is being destroyed by ultraviolet light from the central star. THE INFRARED VIEW -- The composite color image of NGC 7027 (on the left) is among the first data of a planetary nebula taken with NICMOS. This picture is actually composed of three separate images taken at different wavelengths. The red color represents cool molecular hydrogen gas, the most abundant gas in the universe. The image reveals the central star, which is difficult to see in images taken with visible light. Surrounding it is an

  20. FIRST SCIENCE OBSERVATIONS WITH SOFIA/FORCAST: 6-37 {mu}m IMAGING OF ORION BN/KL

    Energy Technology Data Exchange (ETDEWEB)

    De Buizer, James M.; Becklin, E. E.; Zinnecker, Hans; Shuping, Ralph Y.; Vacca, William D. [SOFIA-USRA, NASA Ames Research Center, MS N211-3, Moffett Field, CA 94035 (United States); Morris, Mark R. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States); Herter, Terry L.; Adams, Joseph D., E-mail: jdebuizer@sofia.usra.edu [Center for Radiophysics and Space Research, Cornell University, 208 Space Sciences Building, Ithaca, NY 14853 (United States)

    2012-04-20

    The Becklin-Neugebauer/Kleinmann-Low (BN/KL) region of the Orion Nebula is the nearest region of high-mass star formation in our galaxy. As such, it has been the subject of intense investigation at a variety of wavelengths, which have revealed it to be brightest in the infrared to submillimeter wavelength regime. Using the newly commissioned SOFIA airborne telescope and its 5-40 {mu}m camera FORCAST, images of the entire BN/KL complex have been acquired. The 31.5 and 37.1 {mu}m images represent the highest resolution observations ({approx}<4'') ever obtained of this region at these wavelengths. These observations reveal that the BN object is not the dominant brightness source in the complex at wavelengths {>=} 31.5 {mu}m and that this distinction goes instead to the source IRc4. It was determined from these images and derived dust color temperature maps that IRc4 is also likely to be self-luminous. A new source of emission has also been identified at wavelengths {>=} 31.5 {mu}m that coincides with the northeastern outflow lobe from the protostellar disk associated with radio source I.