WorldWideScience
 
 
1

The sub-Jupiter mass transiting exoplanet WASP-11b  

CERN Multimedia

We report the discovery of a sub-Jupiter mass exoplanet transiting a magnitude V=11.7 host star 1SWASP J030928.54+304024.7. A simultaneous fit to the transit photometry and radial-velocity measurements yield a planet mass M_p=0.53+-0.07M_J, radius R_p=0.91^{+0.06}_{-0.03}R_J and an orbital period of 3.722465^{+0.000006}_{-0.000008} days. The host star is of spectral type K3V, with a spectral analysis yielding an effective temperature of 4800+-100K and log g=4.45+-0.2. It is amongst the smallest, least massive and lowest luminosity stars known to harbour a transiting exoplanet. WASP-11b is the third least strongly irradiated transiting exoplanet discovered to date, experiencing an incident flux F_p=1.9x10^8 erg s^{-1} cm^{-2} and having an equilibrium temperature T_eq=960+-70K.

West, R G; Hebb, L; Joshi, Y C; Pollacco, D; Simpson, E; Skillen, I; Stempels, H C; Wheatley, P J; Wilson, D; Anderson, D; Bentley, S; Bouchy, F; Enoch, B; Gibson, N; Hébrard, G; Hellier, C; Loeillet, B; Mayor, M; Maxted, P; McDonald, I; Moutou, C; Pont, F; Queloz, D; Smith, A M S; Smalley, B; Street, R A; Udry, S

2008-01-01

2

HAT-P-14b: A 2 Jupiter-mass exoplanet transiting a bright F star  

CERN Document Server

We report the discovery of HAT-P-14b, a fairly massive transiting extrasolar planet orbiting the moderately bright star GSC 3086-00152 (V = 9.98), with a period of P = 4.627669 +/- 0.000005 days. The transit is close to grazing (impact parameter 0.891 +0.007/-0.008) and has a duration of 0.0912 +/- 0.0017 days, with a reference epoch of mid transit of Tc = 2454875.28938 +/- 0.00047 (BJD). The orbit is slightly eccentric (e = 0.107 +/- 0.013), and the orientation is such that occultations are unlikely to occur. The host star is a slightly evolved mid-F dwarf with a mass of 1.386 +/- 0.045 M(Sun), a radius of 1.468 +/- 0.054 R(Sun) effective temperature 6600 +/- 90 K, and a slightly metal-rich composition corresponding to [Fe/H] = +0.11 +/- 0.08. The planet has a mass of 2.232 +/- 0.059 M(Jup) and a radius of 1.150 +/- 0.052 R(Jup), implying a mean density of 1.82 +/- 0.24 g/cm3. Its radius is well reproduced by theoretical models for the 1.3 Gyr age of the system if the planet has a heavy-element fraction of a...

Torres, G; Hartman, J; Kovacs, Geza; Noyes, R W; Latham, D W; Fischer, D A; Johnson, J A; Marcy, G W; Howard, A W; Sasselov, D D; Kipping, D; Stefanik, R P; Esquerdo, G A; Everett, M E; Lazar, J; Papp, I; Sari, P

2010-01-01

3

WASP-78b and WASP-79b: Two highly-bloated hot Jupiter-mass exoplanets orbiting F-type stars in Eridanus  

CERN Document Server

We report the discovery of WASP-78b and WASP-79b, two highly-bloated Jupiter-mass exoplanets orbiting F-type host stars. WASP-78b orbits its V=12.0 host star (TYC 5889-271-1) every 2.175 days and WASP-79b orbits its V=10.1 host star (CD-30 1812) every 3.662 days. A simultaneous fit to WASP and TRAPPIST transit photometry and CORALIE radial-velocity measurements yields planetary masses of 0.89 +/- 0.08 M_Jup and 0.90 +/- 0.08 M_Jup, and radii of 1.70 +/- 0.11 R_Jup and 2.09 +/- 0.14 R_Jup, for WASP-78b and WASP-79b, respectively. The planetary equilibrium temperature of T_P = 2350 +/- 80 K for WASP-78b makes it one of the hottest of the currently known exoplanets. The radius of WASP-79b suggests that it is potentially the largest known exoplanet.

Smalley, B; Collier-Cameron, A; Doyle, A P; Gillon, M; Hellier, C; Jehin, E; Lendl, M; Maxted, P F L; Pepe, F; Pollacco, D; Queloz, D; Segransan, D; Smith, A M S; Southworth, J; Triaud, A H M J; Udry, S; West, R G

2012-01-01

4

DISCOVERY OF A PROBABLE 4-5 JUPITER-MASS EXOPLANET TO HD 95086 BY DIRECT IMAGING  

International Nuclear Information System (INIS)

Direct imaging has only begun to inventory the population of gas giant planets on wide orbits around young stars in the solar neighborhood. Following this approach, we carried out a deep imaging survey in the near-infrared using VLT/NaCo to search for substellar companions. Here we report the discovery of a probable companion orbiting the young (10-17 Myr), dusty, early-type (A8) star HD 95086 at 56 AU in L' (3.8 ?m) images. This discovery is based on observations with more than a year time lapse. Our first epoch clearly revealed the source at ? 10?, while our second epoch lacks good observing conditions, yielding a ? 3? detection. Various tests were thus made to rule out possible artifacts. This recovery is consistent with the signal at the first epoch but requires cleaner confirmation. Nevertheless, our astrometric precision suggests that the companion is comoving with the star with a 3? confidence level. The planetary nature of the source is reinforced by a non-detection in the Ks-band (2.18 ?m) images according to its possible extremely red Ks-L' color. Conversely, background contamination is rejected with good confidence level. The luminosity yields a predicted mass of about 4-5 MJup (at 10-17 Myr) using ''hot-start'' evolutionary models, making HD 95086 b the exoplanet with the lowest mass ever imaged around a star

2013-08-01

5

DISCOVERY OF A PROBABLE 4-5 JUPITER-MASS EXOPLANET TO HD 95086 BY DIRECT IMAGING  

Energy Technology Data Exchange (ETDEWEB)

Direct imaging has only begun to inventory the population of gas giant planets on wide orbits around young stars in the solar neighborhood. Following this approach, we carried out a deep imaging survey in the near-infrared using VLT/NaCo to search for substellar companions. Here we report the discovery of a probable companion orbiting the young (10-17 Myr), dusty, early-type (A8) star HD 95086 at 56 AU in L' (3.8 {mu}m) images. This discovery is based on observations with more than a year time lapse. Our first epoch clearly revealed the source at {approx_equal} 10{sigma}, while our second epoch lacks good observing conditions, yielding a {approx_equal} 3{sigma} detection. Various tests were thus made to rule out possible artifacts. This recovery is consistent with the signal at the first epoch but requires cleaner confirmation. Nevertheless, our astrometric precision suggests that the companion is comoving with the star with a 3{sigma} confidence level. The planetary nature of the source is reinforced by a non-detection in the Ks-band (2.18 {mu}m) images according to its possible extremely red Ks-L' color. Conversely, background contamination is rejected with good confidence level. The luminosity yields a predicted mass of about 4-5 M{sub Jup} (at 10-17 Myr) using ''hot-start'' evolutionary models, making HD 95086 b the exoplanet with the lowest mass ever imaged around a star.

Rameau, J.; Chauvin, G.; Lagrange, A.-M.; Delorme, P. [UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France); Boccaletti, A. [LESIA, Observatoire de Paris, CNRS, University Pierre et Marie Curie Paris 6 and University Denis Diderot Paris 7, 5 place Jules Janssen, F-92195 Meudon (France); Quanz, S. P. [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093 Zurich (Switzerland); Bonnefoy, M.; Klahr, H.; Mordasini, C. [Max Planck Institute for Astronomy, Koenigsthul 17, D-69117 Heidelberg (Germany); Girard, J. H.; Dumas, C. [European Southern Observatory, Casilla 19001, Santiago 19 (Chile); Desidera, S.; Bonavita, M., E-mail: julien.rameau@obs.ujf-grenoble.fr [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy)

2013-08-01

6

Three sub-Jupiter-mass planets: WASP-69b & WASP-84b transit active K dwarfs and WASP-70Ab transits the evolved primary of a G4+K3 binary  

CERN Document Server

We report the discovery of the transiting exoplanets WASP-69b, WASP-70Ab and WASP-84b, each of which orbits a bright star (V~10). WASP-69b is a bloated Saturn-mass planet (0.26 M$_{\\rm Jup}$, 1.06 R$_{\\rm Jup}$) in a 3.868-d period around an active mid-K dwarf. We estimate a stellar age of 1 Gyr from both gyrochronological and age-activity relations, though an alternative gyrochronological relation suggests an age of 3 Gyr. ROSAT detected X-rays at a distance of 60$\\pm$27 arcsec from WASP-69. If the star is the source then the planet could be undergoing mass-loss at a rate of ~10$^{12}$ g s$^{-1}$. This is 1-2 orders of magnitude higher than the evaporation rate estimated for HD 209458b and HD 189733b, both of which have exhibited anomalously-large Lyman-{\\alpha} absorption during transit. WASP-70Ab is a sub-Jupiter-mass planet (0.59 M$_{\\rm Jup}$, 1.16R$_{\\rm Jup}$) in a 3.713-d orbit around the primary of a spatially-resolved G4+K3 binary, with a separation of 3.3 arcsec ($\\geq$800 AU). We exploit the binar...

Anderson, D R; Delrez, L; Doyle, A P; Faedi, F; Fumel, A; Gillon, M; Chew, Y Gómez Maqueo; Hellier, C; Jehin, E; Lendl, M; Maxted, P F L; Pepe, F; Pollacco, D; Queloz, D; Ségransan, D; Skillen, I; Smalley, B; Smith, A M S; Southworth, J; Triaud, A H M J; Turner, O D; Udry, S; West, R G

2013-01-01

7

Factors Affecting the Radii of Close-in Transiting Exoplanets  

CERN Document Server

The radius of an exoplanet may be affected by various factors, including irradiation, planet mass and heavy element content. A significant number of transiting exoplanets have now been discovered for which the mass, radius, semi-major axis, host star metallicity and stellar effective temperature are known. We use multivariate regression models to determine the dependence of planetary radius on planetary equilibrium temperature T_eq, planetary mass M_p, stellar metallicity [Fe/H], orbital semi-major axis a, and tidal heating rate H_tidal, for 119 transiting planets in three distinct mass regimes. We determine that heating leads to larger planet radii, as expected, increasing mass leads to increased or decreased radii of low-mass (2.0R_J) planets, respectively (with no mass effect on Jupiter-mass planets), and increased host-star metallicity leads to smaller planetary radii, indicating a relationship between host-star metallicity and planet heavy element content. For Saturn-mass planets, a good fit to the radii...

Enoch, B; Horne, K

2012-01-01

8

Glowing Hot Transiting Exoplanet Discovered  

Science.gov (United States)

VLT Spectra Indicate Shortest-Known-Period Planet Orbiting OGLE-TR-3 Summary More than 100 exoplanets in orbit around stars other than the Sun have been found so far. But while their orbital periods and distances from their central stars are well known, their true masses cannot be determined with certainty, only lower limits. This fundamental limitation is inherent in the common observational method to discover exoplanets - the measurements of small and regular changes in the central star's velocity, caused by the planet's gravitational pull as it orbits the star. However, in two cases so far, it has been found that the exoplanet's orbit happens to be positioned in such a way that the planet moves in front of the stellar disk, as seen from the Earth. This "transit" event causes a small and temporary dip in the star's brightness, as the planet covers a small part of its surface, which can be observed. The additional knowledge of the spatial orientation of the planetary orbit then permits a direct determination of the planet's true mass. Now, a group of German astronomers [1] have found a third star in which a planet, somewhat larger than Jupiter, but only half as massive, moves in front of the central star every 28.5 hours . The crucial observation of this solar-type star, designated OGLE-TR-3 [2] was made with the high-dispersion UVES spectrograph on the Very Large Telescope (VLT) at the ESO Paranal Observatory (Chile). It is the exoplanet with the shortest period found so far and it is very close to the star, only 3.5 million km away. The hemisphere that faces the star must be extremely hot, about 2000 °C and the planet is obviously losing its atmosphere at high rate . PR Photo 10a/03 : The star OGLE-TR-3 . PR Photo 10b/03 : VLT UVES spectrum of OGLE-TR-3. PR Photo 10c/03 : Relation between stellar brightness and velocity (diagram). PR Photo 10d/03 : Observed velocity variation of OGLE-TR-3. PR Photo 10e/03 : Observed brightness variation of OGLE-TR-3. The search for exoplanets More than 100 planets in orbit around stars other than the Sun have been found so far. These "exoplanets" come in many different sizes and they move in a great variety of orbits at different distances from their central star, some nearly round and others quite elongated. Some planets are five to ten times more massive than the largest one in the solar system, Jupiter - the lightest exoplanets known at this moment are about half as massive as Saturn, i.e. about 50 times more massive than the Earth. Astronomers are hunting exoplanets not just to discover more such objects, but also to learn more about the apparent diversity of planetary systems. The current main research goal is to eventually discover an Earth-like exoplanet, but the available telescopes and instrumentation are still not "sensitive" enough for this daunting task. However, also in this context, it is highly desirable to know not only the orbits of the observable exoplanets, but also their true masses . But this is not an easy task. Masses of exoplanets Virtually all exoplanets detected so far have been found by an indirect method - the measurement of stellar velocity variations . It is based on the gravitational pull of the orbiting planet that causes the central star to move a little back and forth; the heavier the planet, the greater is the associated change in the star's velocity. This technique is rapidly improving: the new HARPS spectrograph (High Accuracy Radial Velocity Planet Searcher) , now being tested on the 3.6-m telescope at the ESO La Silla Observatory , can measure such stellar motions with an unrivalled accuracy of about 1 metre per second (m/s), cf. ESO PR 06/03 . It will shortly be able to search for exoplanets only a few times more massive than the Earth. However, velocity measurements alone do not allow to determine the true mass of the orbiting planet. Because of the unknown inclination of the planetary orbit (to the line-of-sight), they only provide a lower limit to this mass . Additional information about this orbital inclination

2003-04-01

9

Transiting Exoplanet Observations at Grinnell College  

Science.gov (United States)

Grinnell College, a small liberal arts college in Grinnell, Iowa with 1600 undergraduate students, is home to the Grant O. Gale Observatory. Over the past year, we have successfully detected extrasolar planets using the transit method with our 24-inch Cassegrain reflecting telescope equipped with a CCD camera. With little light pollution and an easily accessible observatory, Grinnell College is an optimal location for transiting exoplanet observations. With the current telescope set-up and CCD camera, we have taken time series data and created image calibration and post-processing programs that detect exoplanet transits at high photometric precision. In the future, we will continue to use these observation and data reduction procedures to conduct transiting exoplanet research. Goals for our research program include performing follow-up observations of transiting exoplanet candidates to confirm their planetary nature, searching for additional exoplanets in known planetary systems using the transit timing detection method, tracking long period transiting planets, and refining properties of exoplanets and their host stars. Ground-based transiting planet science is especially important in the post-Kepler era, and our dedicated mid-sized telescope with plenty of access to dark clear nights provides an ideal resource for a variety of follow up and exoplanet detection efforts.

Sauerhaft, Julia; Slough, P.; Cale, B.; Kempton, E.

2014-01-01

10

Young Exoplanet Transit Initiative (YETI)  

CERN Document Server

We present the Young Exoplanet Transit Initiative (YETI), in which we use several 0.2 to 2.6m telescopes around the world to monitor continuously young (< 100 Myr), nearby (< 1 kpc) stellar clusters mainly to detect young transiting planets (and to study other variability phenomena on time-scales from minutes to years). The telescope network enables us to observe the targets continuously for several days in order not to miss any transit. The runs are typically one to two weeks long, about three runs per year per cluster in two or three subsequent years for about ten clusters. There are thousands of stars detectable in each field with several hundred known cluster members, e.g. in the first cluster observed, Tr-37, a typical cluster for the YETI survey, there are at least 469 known young stars detected in YETI data down to R=16.5 mag with sufficient precision of 50 milli-mag rms (5 mmag rms down to R=14.5 mag) to detect transits, so that we can expect at least about one young transiting object in this cl...

Neuhäuser, R; Berndt, A; Maciejewski, G; Takahashi, H; Chen, W P; Dimitrov, D P; Pribulla, T; Nikogossian, E H; Jensen, E L N; Marschall, L; Wu, Z -Y; Kellerer, A; Walter, F M; Briceño, C; Chini, R; Fernandez, M; Raetz, St; Torres, G; Latham, D W; Quinn, S N; Niedzielski, A; Bukowiecki, ?; Nowak, G; Tomov, T; Tachihara, K; Hu, S C -L; Hung, L W; Radeva, D P Kjurkchieva \\and V S; Mihov, B M; Slavcheva-Mihova, L; Bozhinova, I N; Budaj, J; Va?ko, M; Kundra, E; Hambálek, ?; Krushevska, V; Movsessian, T; Harutyunyan, H; Downes, J J; Hernandez, J; Hoffmeister, V H; Cohen, D H; Abel, I; Ahmad, R; Chapman, S; Eckert, S; Goodman, J; Guerard, A; Kim, H M; Koontharana, A; Sokol, J; Trinh, J; Wang, Y; Zhou, X; Redmer, R; Kramm, U; Nettelmann, N; Mugrauer, M; Schmidt, J; Moualla, M; Ginski, C; Marka, C; Adam, C; Seeliger, M; Baar, S; Roell, T; Schmidt, T O B; Trepl, L; Eisenbei\\ss, T; Fiedler, S; Tetzlaff, N; Schmidt, E; Hohle, M M; Kitze, M; Chakrova, N; Gräfe, C; Schreyer, K; Hambaryan, V V; Broeg, C H; Koppenhoefer, J; Pandey, A K

2011-01-01

11

The Transiting Exoplanet Survey Satellite  

CERN Document Server

The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, TESS will employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with I<13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from one month to one year, depending mainly on the star's ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10-100 times brighter than those surveyed by the pioneering Kepler missio...

Ricker, George R; Vanderspek, Roland; Latham, David W; Bakos, Gaspar A; Bean, Jacob L; Berta-Thompson, Zachory K; Brown, Timothy M; Buchhave, Lars; Butler, Nathaniel R; Butler, R Paul; Chaplin, William J; Charbonneau, David; Christensen-Dalsgaard, Jorgen; Clampin, Mark; Deming, Drake; Doty, John; De Lee, Nathan; Dressing, Courtney; Dunham, E W; Endl, Michael; Fressin, Francois; Ge, Jian; Henning, Thomas; Holman, Matthew J; Howard, Andrew W; Ida, Shigeru; Jenkins, Jon; Jernigan, Garrett; Johnson, John Asher; Kaltenegger, Lisa; Kawai, Nobuyuki; Kjeldsen, Hans; Laughlin, Gregory; Levine, Alan M; Lin, Douglas; Lissauer, Jack J; MacQueen, Phillip; Marcy, Geoffrey; McCullough, P R; Morton, Timothy D; Narita, Norio; Paegert, Martin; Palle, Enric; Pepe, Francesco; Pepper, Joshua; Quirrenbach, Andreas; Rinehart, S A; Sasselov, Dimitar; Sato, Bun'ei; Seager, Sara; Sozzetti, Alessandro; Stassun, Keivan G; Sullivan, Peter; Szentgyorgyi, Andrew; Torres, Guillermo; Udry, Stephane; Villasenor, Joel

2014-01-01

12

The SuperWASP exoplanet transit survey  

Science.gov (United States)

SuperWASP (Wide Angle Search for Planets) uses robotic installations on La Palma (Canary Islands, Spain) and at Sutherland (South Africa) to survey the sky for transiting exoplanets. At each site, there is an instrument consisting of eight 200 mm camera lenses (0.11 m aperture) backed with Andor e2v CCDs, arranged on a single equatorial fork mount. WASP is responsible for the discovery of 109 transiting exoplanets to date (70 of which have been announced in published papers); more than any other ground-based survey. Besides reviewing the instrumentation and observing strategy, we briefly outline the motivation for such a survey and discuss the place of WASP in the context of similar surveys. We also describe the planet discovery process and the impact of our discoveries on the exoplanets field. The science impact of WASP is not, however, limited to exoplanets; we also summarise some of the non-exoplanet science (including asteroseismology, binary stars, and comets) that has resulted from WASP data. Finally, we discuss the future of WASP and of small aperture, ground-based exoplanet surveys in general, including the forthcoming Next Generation Transit Survey (NGTS).

Smith, A. M. S.; WASP Consortium

2014-03-01

13

Nightside Pollution of Exoplanet Transit Depths  

CERN Multimedia

Out of the known transiting extrasolar planets, the majority are gas giants orbiting their host star at close proximity. Both theoretical and observational studies support the hypothesis that such bodies emit significant amounts of flux, especially at mid-infrared wavelengths. For the dayside of the exoplanet, this phenomenon typically permits detectable secondary eclipses at such wavelengths, which may be used to infer atmospheric composition. In this paper, we explore the effects of emission from the nightside of the exoplanet on the primary transit lightcurve. Allowing for nightside emission, an exoplanet's transit depth is no longer exclusively a function of the ratio-of-radii. The nightside of an exoplanet is emitting flux and the contrast to the star's emission is of the order of ~10^(-3) for hot-Jupiters. Consequently, we show that the transit depth in the mid-infrared will be attenuated due to flux contribution from the nightside emission by ~10^(-4). We show how this effect can be compensated for in ...

Kipping, David M

2009-01-01

14

Transit Monitoring of Known Exoplanets with TERMS  

Science.gov (United States)

Transiting planet discoveries have yielded a plethora of information regarding the internal structure and atmospheres of extra-solar planets. These discoveries have been restricted to the low-periastron distance regime due to the bias inherent in the geometric transit probability. Monitoring known radial velocity planets at predicted transit times is a proven method of detecting transits, and presents an avenue through which to explore the mass-radius relationship of exoplanets in new regions of period/periastron space. Here we describe transit window calculations for known radial velocity planets, techniques for refining their transit ephemerides, and observational methods for obtaining maximum coverage of transit windows. These methods are currently being implemented by the Transit Ephemeris Refinement and Monitoring Survey (TERMS), from which we present the latest results.

Kane, Stephen R.; Ciardi, D.; Fischer, D.; Gelino, D.; Henry, G.; Howard, A.; Jensen, E.; Laughlin, G.; Mahadevan, S.; Pilyavsky, G.; von Braun, K.; Wright, J.

2011-01-01

15

Refining Exoplanet Ephemerides and Transit Observing Strategies  

CERN Multimedia

Transiting planet discoveries have yielded a plethora of information regarding the internal structure and atmospheres of extra-solar planets. These discoveries have been restricted to the low-periastron distance regime due to the bias inherent in the geometric transit probability. Monitoring known radial velocity planets at predicted transit times is a proven method of detecting transits, and presents an avenue through which to explore the mass-radius relationship of exoplanets in new regions of period/periastron space. Here we describe transit window calculations for known radial velocity planets, techniques for refining their transit ephemerides, target selection criteria, and observational methods for obtaining maximum coverage of transit windows. These methods are currently being implemented by the Transit Ephemeris Refinement and Monitoring Survey (TERMS).

Kane, Stephen R; von Braun, Kaspar; Laughlin, Gregory; Ciardi, David R

2009-01-01

16

TERMS Photometry of Known Transiting Exoplanets  

CERN Multimedia

The Transit Ephemeris Refinement and Monitoring Survey (TERMS) conducts radial velocity and photometric monitoring of known exoplanets in order to refine planetary orbits and predictions of possible transit times. This effort is primarily directed towards planets not known to transit, but a small sample of our targets consist of known transiting systems. Here we present precision photometry for 6 WASP planets acquired during their transit windows. We perform a Markov Chain Monte Carlo (MCMC) analysis for each planet and combine these data with previous measurements to redetermine the period and ephemerides for these planets. These observations provide recent mid-transit times which are useful for scheduling future observations. Our results improve the ephemerides of WASP-4b, WASP-5b and WASP-6b and reduce the uncertainties on the mid-transit time for WASP-29b. We also confirm the orbital, stellar and planetary parameters of all 6 systems.

Dragomir, Diana; Pilyavsky, Genady; Mahadevan, Suvrath; Ciardi, David R; Gazak, J Zachary; Gelino, Dawn M; Payne, Alan; Rabus, Markus; Ramirez, Solange V; von Braun, Kaspar; Wright, Jason T; Wyatt, Pamela

2011-01-01

17

TERMS Photometry of Known Transiting Exoplanets  

Science.gov (United States)

The Transit Ephemeris Refinement and Monitoring Survey conducts radial velocity and photometric monitoring of known exoplanets in order to refine planetary orbits and predictions of possible transit times. This effort is primarily directed toward planets not known to transit, but a small sample of our targets consists of known transiting systems. Here we present precision photometry for six WASP (Wide Angle Search for Planets) planets acquired during their transit windows. We perform a Markov Chain Monte Carlo analysis for each planet and combine these data with previous measurements to redetermine the period and ephemerides for these planets. These observations provide recent mid-transit times which are useful for scheduling future observations. Our results improve the ephemerides of WASP-4b, WASP-5b, and WASP-6b and reduce the uncertainties on the mid-transit time for WASP-29b. We also confirm the orbital, stellar, and planetary parameters of all six systems.

Dragomir, Diana; Kane, Stephen R.; Pilyavsky, Genady; Mahadevan, Suvrath; Ciardi, David R.; Gazak, J. Zachary; Gelino, Dawn M.; Payne, Alan; Rabus, Markus; Ramirez, Solange V.; von Braun, Kaspar; Wright, Jason T.; Wyatt, Pamela

2011-10-01

18

TERMS and Conditions of Transiting Exoplanets  

Science.gov (United States)

Photometric follow-up of planets discovered by the radial velocity technique have yielded known transiting extra-solar planets, especially for those with the brightest host stars (e.g., HD 209458b). The only limitation to photometric precision is determined by the chosen telescope/instrument and small uncertainties in the timing of the transit. We have conducted follow-up observations of numerous known exoplanets, such as HD 37605 and HD 6434, using the updated Transit Ephemeris Refinement and Monitoring Survey (TERMS) pipeline. We have calculated the transit ephemerides via optimal observing windows and are able to fully characterize the planetary system and possible transit. While the field of exoplanets has expanded to include characterization, these are typically limited to shorter period orbits. Our program extends characterization to a much more diverse range of planetary orbits both in terms of longer periods and higher eccentricities. In the case of a null detection, our photometry is used to place constraints on orbital and astrophysical parameters of the planet.

Hinkel, Natalie R.; Ciardi, D.; Dragomir, D.; Fischer, D.; Henry, G. W.; Howard, A.; Jensen, E. L.; Kane, S. R.; Laughlin, G.; Mahadevan, S.; Pilyavsky, G.; von Braun, K.; Wang, X.; Wright, J.

2013-01-01

19

Searching for transit timing variations in transiting exoplanet systems  

CERN Multimedia

Searching for transit timing variations in the known transiting exoplanet systems can reveal the presence of other bodies in the system. Here we report such searches for two transiting exoplanet systems, TrES-1 and WASP-2. Their new transits were observed with the 4.2m William Herschel Telescope located on La Palma, Spain. In a continuing programme, three consecutive transits were observed for TrES-1, and one for WASP-2 during September 2007. We used the Markov Chain Monte Carlo simulations to derive transit times and their uncertainties. The resulting transit times are consistent with the most recent ephemerides and no conclusive proof of additional bodies in either system was found.

Hrudková, Marie; Benn, Chris; Pollacco, Don; Gibson, Neale; Joshi, Yogesh; Harmanec, Petr; Tulloch, Simon

2008-01-01

20

The WASP-South search for transiting exoplanets  

Directory of Open Access Journals (Sweden)

Full Text Available Since 2006 WASP-South has been scanning the Southern sky for transiting exoplanets. Combined with Geneva Observatory radial velocities we have so far found over 30 transiting exoplanets around relatively bright stars of magnitude 9–13. We present a status report for this ongoing survey.

Queloz D.

2011-02-01

 
 
 
 
21

Transiting exoplanets: From planet statistics to their physical nature  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The colloquium "Detection and Dynamics of Transiting Exoplanets" was held at the Observatoire de Haute-Provence and discussed the status of transiting exoplanet investigations in a 4.5 day meeting. Topics addressed ranged from planet detection, a discussion on planet composition and interior structure, atmospheres of hot-Jupiter planets, up to the e?ect of tides and the dynamical evolution of planetary systems. Here, I give a summary of the recent developments of transiting planet detection...

Rauer H.

2011-01-01

22

High precision transit observations of the exoplanet WASP-13b with the RISE instrument  

CERN Document Server

WASP-13b is a sub-Jupiter mass exoplanet orbiting a G1V type star with a period of 4.35 days. The current uncertainty in its impact parameter (0 < b < 0.46) resulted in poorly defined stellar and planetary radii. To better constrain the impact parameter we have obtained high precision transit observations with the RISE instrument mounted on 2.0 m Liverpool Telescope. We present four new transits which are fitted with an MCMC routine to derive accurate system parameters. We found an orbital inclination of 85.2 \\pm 0.3 degrees resulting in stellar and planetary radii of 1.56 \\pm 0.04 R\\odot and 1.39 \\pm 0.05 RJup, respectively. This suggests that the host star has evolved off the main-sequence and is in the shell hydrogen-burning phase. We also discuss how the limb darkening affects the derived system parameters. With a density of 0.17{\\rho}J, WASP-13b joins the group of low density planets whose radii are too large to be explained by standard irradiation models. We derive a new ephemeris for the system, ...

Barros, S C C; Gibson, N P; Keenan, F P; Skillen, I; Steele, I A

2011-01-01

23

The observation of exoplanet transit events in China  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have carried out a research project on the exoplanet transit events at Yunnan Observatory. By using CCD cameras attached to 1m telescope of Yunnan Observatory and 85cm telescope of Xinglong station, NAOC, a group of exoplanet systems with transit events have been observed photometrically. By means of MCMC method, the preliminary results of the systems WASP-11 and XO-2 are derived. Finally, we give out the future plan on this research topic in China.

-b, Wang X.; -h, Gu S.; Collier Cameron A.; -s, Fang X.

2011-01-01

24

Carbon monoxide and water vapor in the atmosphere of the non-transiting exoplanet HD 179949 b  

CERN Multimedia

(Abridged) In recent years, ground-based high-resolution spectroscopy has become a powerful tool for investigating exoplanet atmospheres. It allows the robust identification of molecular species, and it can be applied to both transiting and non-transiting planets. Radial-velocity measurements of the star HD 179949 indicate the presence of a giant planet companion in a close-in orbit. Here we present the analysis of spectra of the system at 2.3 micron, obtained at a resolution of R~100,000, during three nights of observations with CRIRES at the VLT. We targeted the system while the exoplanet was near superior conjunction, aiming to detect the planet's thermal spectrum and the radial component of its orbital velocity. We detect molecular absorption from carbon monoxide and water vapor with a combined S/N of 6.3, at a projected planet orbital velocity of K_P = (142.8 +- 3.4) km/s, which translates into a planet mass of M_P = (0.98 +- 0.04) Jupiter masses, and an orbital inclination of i = (67.7 +- 4.3) degrees, ...

Brogi, M; Birkby, J L; Schwarz, H; Snellen, I A G

2014-01-01

25

Colour Magnitude Diagrams of Transiting Exoplanets  

Science.gov (United States)

Colour-Magnitude diagrams form a traditional way of representing luminous objects in the Universe and compare them to each others. Here, the photometric distances of 44 transiting exoplanetary systems were estimated. For seven of those, parallaxes confirm the methodology. From the combination of those measurements with fluxes obtained while planets were occulted by their host stars, colour-magnitude diagrams are composed in the near and mid IR. When possible, planets are plotted with field brown dwarfs who often have similar sizes and equilibrium temperatures, thus offering a natural empirical comparison sample. Exoplanets are also compared to the expected loci of pure blackbodies. In general planets do not agree with the brown dwarfs sequences, and neither do they match blackbodies. It is however possible to affirm that they are not featureless and that they display an increasing diversity in colour with decreasing intrinsic luminosity. A missing source of absorption within the [4.5 ?m] band, for some planets, would generally reconcile hot Jupiters with brown dwarfs’ cool atmospheres. Alternatively, measuring the emission of gas giants cooler than 1 000 K would disentangle whether planets’ atmospheres behave like brown dwarfs’ atmospheres, like blackbodies, or whether they form their own sequence.

Triaud, Amaury H. M. J.

2014-06-01

26

Improving Transit Predictions of Known Exoplanets with TERMS  

Science.gov (United States)

Transiting planet discoveries have yielded a plethora of information regarding the internal structure and atmospheres of extra-solar planets. These discoveries have largely been restricted to the low-periastron distance regime due to the bias inherent in the geometric transit probability. Monitoring known radial velocity planets at predicted transit times is a proven method of detecting transits, and presents an avenue through which to explore the mass-radius relationship of exoplanets in new regions of period/periastron space for the brightest exoplanet host stars. Here we describe transit window calculations for known radial velocity planets, techniques for refining their transit ephemerides, and present results for radial velocity planets which have been successfully monitored during predicted transit times. These methods are currently being implemented by the Transit Ephemeris Refinement and Monitoring Survey (TERMS).

Kane, Stephen R.; Ciardi, D.; Dragomir, D.; Fischer, D.; Henry, G.; Howard, A.; Jensen, E.; Laughlin, G.; Mahadevan, S.; Pilyavsky, G.; von Braun, K.; Wright, J.

2011-05-01

27

Transiting Exoplanet Simulations with the James Webb Space Telescope  

Science.gov (United States)

The James Webb Space Telescope (JWST) was ranked as the top science priority in the 2000 Astronomy & Astrophysics Decadal Survey. We assess the potential for JWST to characterize the atmospheres of super-Earth exoplanets, by simulating a range of transiting spectra with different masses and temperatures. Our results are based on a JWST simulator tuned to the expected performance of the spectroscopic instruments NIRSpec and NIRISS, and is based on the latest exoplanet transit models. This study is especially timely since the observing modes for the science instruments on JWST are finalized and because NASA has selected the TESS mission as an upcoming Explorer.

Batalha, Natasha; Kalirai, J. S.; Lunine, J. I.; Mandell, A.

2014-01-01

28

Interpreting low spectral resolution data of transiting exoplanets  

Science.gov (United States)

During primary transit transmission spectra of the exoplanet's limb are recorded as the planet passes in front of the star. During secondary eclipse, measurements yield the planetary emission spectra. Photometry and spectroscopy of transiting exoplanets indicate the presence of water, methane, carbon monoxide and potentially carbon dioxide in a number of extrasolar planets [1, 2, 3, 4, 5, 6]. Observations at different points in an exoplanet's orbit also reveal variations in the planet's temperature field with longitude, which manifest the planet's dynamical redistribution of heat [7]. Yet even for the brightest systems, molecular abundances are constrained only to within 3-5 orders ofmagnitude and temperatures as a function of pressure to roughly 300 K. A large part the uncertainties stem from the range of models that fit the data. Here we explore the degeneracies in the solution sets with the aim to better constrain and measure planetary characteristics.

Griffith, C. A.; Turner, J. D.; Zellem, R.; Tinetti, G.; Teske, J.

2013-09-01

29

TASTE: The Asiago Survey for Timing transit variations of Exoplanets  

CERN Document Server

A promising method to detect earth-sized exoplanets is the timing analysis of a known transit. The technique allows a search for variations in transit duration or center induced by the perturbation of a third body, e.g. a second planet or an exomoon. To this aim, TASTE (The Asiago Survey for Timing transit variations of Exoplanets) project will collect high-precision, short-cadence light curves for a selected sample of transits by using imaging differential photometry at the Asiago 1.82m telescope. The first light curves show that our project can already provide a competitive timing accuracy, as well as a significant improvement over the orbital parameters. We derived refined ephemerides for HAT-P-3b and HAT-P-14b with only one transit each, thanks to a timing accuracy of 11 and 25 s, respectively.

Nascimbeni, V; Bedin, L R; Damasso, M

2010-01-01

30

ExoplanetSat: detecting transiting exoplanets using a low-cost CubeSat platform  

Science.gov (United States)

Nanosatellites, i.e. spacecraft that weigh between 1 and 10 kg, are drawing increasing interest as platforms for conducting on-orbit science. This trend is primarily driven by the ability to piggyback nanosatellites on the launch of large spacecraft and hence achieve orbit at greatly reduced cost. The CubeSat platform is a standardized nanosatellite configuration, consisting of one, two, or three 10 cm x 10 cm x 10 cm units (1, 2, or 3 "U"s) arranged in a row. We present a CubeSat-based concept for the discovery of transiting exoplanets around the nearest and brightest Sun-like stars. The spacecraft prototype - termed ExoplanetSat - is a 3U space telescope capable of monitoring a single target star from low Earth orbit. Given the volume limitations of the CubeSat form factor, designing a capable spacecraft requires overcoming significant challenges. This work presents the initial satellite configuration along with several subsystem-specific solutions to the aforementioned constraints. An optical design based on a modified commercial off-the-shelf camera lens is given. We also describe a novel two-stage attitude control architecture that combines 3-axis reaction wheels for coarse pointing with a piezoelectric translation stage at the focal plane for fine pointing. Modeling and simulation results are used to demonstrate feasibility by quantifying ExoplanetSat pointing precision, signal-to-noise ratio, guide star magnitude, and additional design parameters which determine system performance.

Smith, Matthew W.; Seager, Sara; Pong, Christopher M.; Villaseñor, Jesus S.; Ricker, George R.; Miller, David W.; Knapp, Mary E.; Farmer, Grant T.; Jensen-Clem, Rebecca

2010-07-01

31

THE LOW DENSITY TRANSITING EXOPLANET WASP-15b  

International Nuclear Information System (INIS)

We report the discovery of a low-density exoplanet transiting an 11th magnitude star in the Southern hemisphere. WASP-15b, which orbits its host star with a period P = 3.7520656 ± 0.0000028 d, has a mass M p = 0.542 ± 0.050 M J and radius R p = 1.428 ± 0.077 R J, and is therefore one of the least dense transiting exoplanets so far discovered (?p = 0.247 ± 0.035 g cm-3). An analysis of the spectrum of the host star shows it to be of spectral type around F5, with an effective temperature T eff = 6300 ± 100 K and [Fe/H] = -0.17 ± 0.11.

2009-06-01

32

Kepler mission exoplanet transit data analysis using fractal imaging  

Science.gov (United States)

The Kepler mission is designed to survey a fist-sized patch of the sky within the Milky Way galaxy for the discovery of exoplanets, with emphasis on near Earth-size exoplanets in or near the habitable zone. The Kepler space telescope would detect the brightness fluctuation of a host star and extract periodic dimming in the lightcurve caused by exoplanets that cross in front of their host star. The photometric data of a host star could be interpreted as an image where fractal imaging would be applicable. Fractal analysis could elucidate the incomplete data limitation posed by the data integration window. The fractal dimension difference between the lower and upper halves of the image could be used to identify anomalies associated with transits and stellar activity as the buried signals are expected to be in the lower half of such an image. Using an image fractal dimension resolution of 0.04 and defining the whole image fractal dimension as the Chi-square expected value of the fractal dimension, a p-value can be computed and used to establish a numerical threshold for decision making that may be useful in further studies of lightcurves of stars with candidate exoplanets. Similar fractal dimension difference approaches would be applicable to the study of photometric time series data via the Higuchi method. The correlated randomness of the brightness data series could be used to support inferences based on image fractal dimension differences. Fractal compression techniques could be used to transform a lightcurve image, resulting in a new image with a new fractal dimension value, but this method has been found to be ineffective for images with high information capacity. The three studied criteria could be used together to further constrain the Kepler list of candidate lightcurves of stars with possible exoplanets that may be planned for ground-based telescope confirmation.

Dehipawala, S.; Tremberger, G.; Majid, Y.; Holden, T.; Lieberman, D.; Cheung, T.

2012-10-01

33

Refining Exoplanet Ephemerides and Transit Observing Strategies  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transiting planet discoveries have yielded a plethora of information regarding the internal structure and atmospheres of extra-solar planets. These discoveries have been restricted to the low-periastron distance regime due to the bias inherent in the geometric transit probability. Monitoring known radial velocity planets at predicted transit times is a proven method of detecting transits, and presents an avenue through which to explore the mass-radius relationship of exoplan...

Kane, Stephen R.; Mahadevan, Suvrath; Von Braun, Kaspar; Laughlin, Gregory; Ciardi, David R.

2009-01-01

34

Direct Detection of Exoplanets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Direct detection of exoplanets from the ground is now within reach of existing astronomical instruments. Indeed, a few planet candidates have already been imaged and analyzed and the capability to detect (through imaging or interferometry) young, hot, Jupiter-mass planets exists. We present here an overview of what such detection methods can be expected to do in the near and far term. These methods will provide qualitatively new information about exoplanets, including spectroscopic data that ...

Beuzit, Jean-luc; Mouillet, David; Oppenheimer, Ben R.; Monnier, John D.

2006-01-01

35

KELT-1b: A STRONGLY IRRADIATED, HIGHLY INFLATED, SHORT PERIOD, 27 JUPITER-MASS COMPANION TRANSITING A MID-F STAR  

Energy Technology Data Exchange (ETDEWEB)

We present the discovery of KELT-1b, the first transiting low-mass companion from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North) transit survey. A joint analysis of the spectroscopic, radial velocity, and photometric data indicates that the V = 10.7 primary is a mildly evolved mid-F star with T{sub eff} = 6516 {+-} 49 K, log g 4.228{sup +0.014}{sub -0.021}, and [Fe/H] = 0.052 {+-} 0.079, with an inferred mass M{sub *} = 1.335 {+-} 0.063 M{sub Sun} and radius R{sub *} 1.471{sup +0.045}{sub -0.035} R{sub Sun }. The companion is a low-mass brown dwarf or a super-massive planet with mass M{sub P} = 27.38 {+-} 0.93 M{sub Jup} and radius R{sub P} = 1.116{sup +0.038}{sub -0.029} R{sub Jup}. The companion is on a very short ({approx}29 hr) period circular orbit, with an ephemeris T{sub c} (BJD{sub TDB}) = 2455909.29280 {+-} 0.00023 and P = 1.217501 {+-} 0.000018 days. KELT-1b receives a large amount of stellar insolation, resulting in an estimated equilibrium temperature assuming zero albedo and perfect redistribution of T{sub eq} = 2423{sup +34}{sub -27} K. Comparison with standard evolutionary models suggests that the radius of KELT-1b is likely to be significantly inflated. Adaptive optics imaging reveals a candidate stellar companion to KELT-1 with a separation of 588 {+-} 1 mas, which is consistent with an M dwarf if it is at the same distance as the primary. Rossiter-McLaughlin measurements during transit imply a projected spin-orbit alignment angle {lambda} = 2 {+-} 16 deg, consistent with a zero obliquity for KELT-1. Finally, the vsin I{sub *} = 56 {+-} 2 km s{sup -1} of the primary is consistent at {approx}2{sigma} with tidal synchronization. Given the extreme parameters of the KELT-1 system, we expect it to provide an important testbed for theories of the emplacement and evolution of short-period companions, as well as theories of tidal dissipation and irradiated brown dwarf atmospheres.

Siverd, Robert J.; Pepper, Joshua; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Beatty, Thomas G.; Scott Gaudi, B. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Eastman, Jason D.; Street, Rachel; Fulton, Benjamin J. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117 (United States); Collins, Karen [Department of Physics and Astronomy, University of Louisville, Louisville, KY 40292 (United States); Bieryla, Allyson; Latham, David W.; Berlind, Perry; Calkins, Michael L.; Esquerdo, Gilbert A.; Furesz, Gabor; Geary, John C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Buchhave, Lars A. [Niels Bohr Institute, University of Copenhagen, Juliane Maries vej 30, DK-21S00 Copenhagen (Denmark); Jensen, Eric L. N. [Department of Physics and Astronomy, Swarthmore College, Swarthmore, PA 19081 (United States); Crepp, Justin R. [Department of Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); DePoy, D. L. [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); and others

2012-12-20

36

Five kepler target stars that show multiple transiting exoplanet candidates  

DEFF Research Database (Denmark)

We present and discuss five candidate exoplanetary systems identified with the Kepler spacecraft. These five systems show transits from multiple exoplanet candidates. Should these objects prove to be planetary in nature, then these five systems open new opportunities for the field of exoplanets and provide new insights into the formation and dynamical evolution of planetary systems. We discuss the methods used to identify multiple transiting objects from the Kepler photometry as well as the false-positive rejection methods that have been applied to these data. One system shows transits from three distinct objects while the remaining four systems show transits from two objects. Three systems have planet candidates that are near mean motion commensurabilitiesâ??two near 2:1 and one just outside 5:2. We discuss the implications that multi-transiting systems have on the distribution of orbital inclinations in planetary systems, and hence their dynamical histories, as well as their likely masses and chemical compositions. A Monte Carlo study indicates that, with additional data, most of these systems should exhibit detectable transit timing variations (TTVs) due to gravitational interactions, though none are apparent in these data. We also discuss new challenges that arise in TTV analyses due to the presence of more than two planets in a system.

Steffen..[], Jason H.; Batalha, N. M.

2010-01-01

37

FIVE KEPLER TARGET STARS THAT SHOW MULTIPLE TRANSITING EXOPLANET CANDIDATES  

International Nuclear Information System (INIS)

We present and discuss five candidate exoplanetary systems identified with the Kepler spacecraft. These five systems show transits from multiple exoplanet candidates. Should these objects prove to be planetary in nature, then these five systems open new opportunities for the field of exoplanets and provide new insights into the formation and dynamical evolution of planetary systems. We discuss the methods used to identify multiple transiting objects from the Kepler photometry as well as the false-positive rejection methods that have been applied to these data. One system shows transits from three distinct objects while the remaining four systems show transits from two objects. Three systems have planet candidates that are near mean motion commensurabilities-two near 2:1 and one just outside 5:2. We discuss the implications that multi-transiting systems have on the distribution of orbital inclinations in planetary systems, and hence their dynamical histories, as well as their likely masses and chemical compositions. A Monte Carlo study indicates that, with additional data, most of these systems should exhibit detectable transit timing variations (TTVs) due to gravitational interactions, though none are apparent in these data. We also discuss new challenges that arise in TTV analyses due to the presence of more than two planets in a system.

2010-12-10

38

RATS: Italian project fore exoplanets transit search  

Science.gov (United States)

The RATS (RAdial velocity and Transit Search) project is a collaboration among INAF sections of Catania, Napoli, Padova and Palermo the Physics and Astronomy departments of Padua University and ESA. The main goal of the project is to discover at least 10 news planets transiting the host star. We also report on the characteristics and the performances of the CCD cameras that will be used by the project. We describe the characterization measurements done in laboratory and the first tests at the Asiago Schmidt telescope at Cima Ekar. Finally, we present the concept of an IRAF-based automatic data-reduction pipeline for RATS.

Granata, V.; Claudi, R. U.; Baruffolo, A.; Bruno, P.; Contri, L.; Favata, F.; Montalto, M.; Piotto, G. P.; Scuderi, S.

39

H? Absorption in Transiting Exoplanet Atmospheres  

Science.gov (United States)

Recent observations by Jensen et al. of H? absorption by the upper atmosphere of HD189733b have motivated the need for a theoretical understanding of the distribution of n=2 hydrogen within hot Jupiter atmospheres. With this in mind, we model the n=2 state of atomic hydrogen in a hydrostatic atmosphere in thermal and photoionization equilibrium. Both collisional and radiative transitions are included in the calculation of the n = 2 state level population. In our model, the H? absorption is dominated by a ? ~ 1 shell composed of metastable 2s hydrogen located within the neutral atomic layer, with the contribution coming roughly uniformly throughout the layer instead of from a specific impact parameter. An ionization rate an order of magnitude over the expected value can reproduce the observed transit depth.

Christie, Duncan; Arras, Phil; Li, Zhi-Yun

2014-01-01

40

WASP-29b: A SATURN-SIZED TRANSITING EXOPLANET  

International Nuclear Information System (INIS)

We report the discovery of a Saturn-sized planet transiting a V = 11.3, K4 dwarf star every 3.9 days. WASP-29b has a mass of 0.24 ± 0.02 M Jup and a radius of 0.79 ± 0.05 R Jup, making it the smallest planet so far discovered by the WASP survey, and the exoplanet most similar in mass and radius to Saturn. The host star WASP-29 has an above-solar metallicity and fits a possible correlation for Saturn-mass planets such that planets with higher-metallicity host stars have higher core masses and thus smaller radii.

2010-11-01

 
 
 
 
41

Optimizing exoplanet transit searches (Herrero+, 2012)  

Science.gov (United States)

The table is a compilation of several catalogs of stars containing log(R'HK), vsin(i) and (B-V) data. The statistical analysis described in the paper was performed to obtain the probability for each star to have an axis inclination above 80°, given by the parameters epsilon and P. The number of stars contained in the statistics box, described by the uncertainties in the defined parameters, is also indicated. The resulting probabilities can be used to constrain the sample and compile a catalog for high efficiency transit searches. (1 data file).

Herrero, E.; Ribas, I.; Jordi, C.; Guinan, E. F.; Scott, S. G.

2011-11-01

42

Homogeneous Characterization of Transiting Exoplanet Systems  

Science.gov (United States)

We present the analysis of an homogeneous set of high resolution (R > 40,000), high signal-to-noise (S/N > 150) spectra for a large and diverse sample of stars with transiting planets. We consistently derive stellar parameters such as Teff , [Fe/H], log g, and v sin i by using different spectral characterization tools to derive the best parameters with formal and systematic uncertainties. By means of our homogeneous analysis of this high-quality dataset, we are able to investigate any systematic uncertainties on the derived stellar properties, and consequently, on the planetary properties derived from the iterative combination of our spectral analysis with the best available radial velocity data and transit photometry. The resulting consistent set of physical properties allows us to further explore known correlations, e.g., core-size of the planet and stellar metallicity, and to newly identify subtle relationships providing insight into our understanding of planetary formation, structure, and evolution. Our pilot study analyzing our WASP-13 HIRES spectrum (R 48 000, S/N>150) in combination with high precision light curves shows an improvement in the precision of the stellar parameters of 60% in Teff , 75% in [Fe/H], 82% in the stellar mass, and 73% in the stellar radius, which translates into a 64% improvement in the precision of the planetary radius, and more than 2% on the planetary mass, relative to the discovery paper's values.

Gomez Maqueo Chew, Yilen; Faedi, F.; Hebb, L.; Pollacco, D.; Stassun, K. G.; Barros, S. C. C.; Ghezzi, L.; Smalley, B.; Cargile, P.; Santos, N. C.; Sousa, S.; Mack, C.; Doyle, A.

2012-01-01

43

Practical suggestions on detecting exomoons in exoplanet transit light curves  

CERN Multimedia

The number of known transiting exoplanets is rapidly increasing, which has recently inspired significant interest as to whether they can host a detectable moon. Although there has been no such example where the presence of a satellite was proven, several methods have already been investigated for such a detection in the future. All these methods utilize post-processing of the measured light curves, and the presence of the moon is decided by the distribution of a timing parameter. Here we propose a method for the detection of the moon directly in the raw transit light curves. When the moon is in transit, it puts its own fingerprint on the intensity variation. In realistic cases, this distortion is too little to be detected in the individual light curves, and must be amplified. Averaging the folded light curve of several transits helps decrease the scatter, but it is not the best approach because it also reduces the signal. The relative position of the moon varies from transit to transit, the moon's wing will a...

Szabo, Gy M; Kiss, L L; Regaly, Zs

2010-01-01

44

Carbon monoxide and water vapor in the atmosphere of the non-transiting exoplanet HD 179949 b  

Science.gov (United States)

Context. In recent years, ground-based high-resolution spectroscopy has become a powerful tool for investigating exoplanet atmospheres. It allows the robust identification of molecular species, and it can be applied to both transiting and non-transiting planets. Radial-velocity measurements of the star HD 179949 indicate the presence of a giant planet companion in a close-in orbit. The system is bright enough to be an ideal target for near-infrared, high-resolution spectroscopy. Aims: Here we present the analysis of spectra of the system at 2.3 ?m, obtained at a resolution of R ~ 100 000, during three nights of observations with CRIRES at the VLT. We targeted the system while the exoplanet was near superior conjunction, aiming to detect the planet's thermal spectrum and the radial component of its orbital velocity. Methods: Unlike the telluric signal, the planet signal is subject to a changing Doppler shift during the observations. This is due to the changing radial component of the planet orbital velocity, which is on the order of 100-150 km s-1 for these hot Jupiters. We can therefore effectively remove the telluric absorption while preserving the planet signal, which is then extracted from the data by cross correlation with a range of model spectra for the planet atmosphere. Results: We detect molecular absorption from carbon monoxide and water vapor with a combined signal-to-noise ratio (S/N) of 6.3, at a projected planet orbital velocity of KP = (142.8 ± 3.4) km s-1, which translates into a planet mass of MP = (0.98 ± 0.04) Jupiter masses, and an orbital inclination of i = (67.7 ± 4.3) degrees, using the known stellar radial velocity and stellar mass. The detection of absorption features rather than emission means that, despite being highly irradiated, HD 179949 b does not have an atmospheric temperature inversion in the probed range of pressures and temperatures. Since the host star is active (R'HK > -4.9), this is in line with the hypothesis that stellar activity damps the onset of thermal inversion layers owing to UV flux photo-dissociating high-altitude, optical absorbers. Finally, our analysis favors an oxygen-rich atmosphere for HD 179949 b, although a carbon-rich planet cannot be statistically ruled out based on these data alone. Based on observations collected at the ESO Very Large Telescope during the Program 186.C-0289.

Brogi, M.; de Kok, R. J.; Birkby, J. L.; Schwarz, H.; Snellen, I. A. G.

2014-05-01

45

Transiting exoplanets from the CoRoT space mission. XVI. CoRoT-14b: an unusually dense very hot Jupiter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, the CoRoT ExoplanetScience Team announces its 14th discovery. Herein, we discuss the observations and analyses that allowed us to derive the parameters of this system: a hot Jupiter with a mass of 7.6 ± 0.6 Jupiter masses orbiting a solar-type star (F9V) with a period of only 1.5 d, less than 5 stellar radii from its parent star. It is unusual for such a massive planet to have such a small orbit: only one other known higher mass exoplanet orbits with a shorter period. The CoR...

2011-01-01

46

Engaging Undergraduate Students in Transiting Exoplanet Research with Small Telescopes  

Science.gov (United States)

Brigham Young University has a relatively large undergraduate physics program with 300 to 360 physics majors. Each of these students is required to be engaged in a research group and to produce a senior thesis before graduating. For the astronomy professors, this means that each of us is mentoring at least 4-6 undergraduate students at any given time. For the past few years I have been searching for meaningful research projects that make use of our telescope resources and are exciting for both myself and my students. We first started following up Kepler Objects of Interest with our 0.9 meter telescope, but quickly realized that most of the transits we could observe were better analyzed with Kepler data and were false positive objects. So now we have joined a team that is searching for transiting planets, and my students are using our 16" telescope to do ground based follow-up on the hundreds of possible transiting planet candidates produced by this survey. In this presentation I will describe our current telescopes, the observational setup, and how we use our telescopes to search for transiting planets. I'll describe some of the software the students have written. I'll also explain how to use the NASA Exoplanet Archive to gather data on known transiting planets and Kepler Objects of Interests. These databases are useful for determining the observational limits of your small telescopes and teaching your students how to reduce and report data on transiting planets. Once that is in place, you are potentially ready to join existing transiting planet missions by doing ground-based follow-up. I will explain how easy it can be to implement this type of research at any high school, college, or university with a small telescope and CCD camera.

Stephens, Denise C.; Stoker, E.; Gaillard, C.; Ranquist, E.; Lara, P.; Wright, K.

2013-10-01

47

Optical Observations of the Transiting Exoplanet GJ 1214b  

Science.gov (United States)

We observed nine primary transits of the super-Earth exoplanet GJ 1214b in several optical photometric bands from March to August 2012, with the goal of constraining the short wavelength slope of the spectrum of GJ 1214b. Our observations were conducted on the Kuiper 1.55 m telescope in Arizona and the STELLA-I robotic 1.2 m telescope in Tenerife, Spain. From the derived light curves we extracted transit depths in R , V , and g? bands. We originally fit our data using the publically available modeling software, Transit Analysis Package (TAP). However, we found that TAP overestimates the amount of red noise in our transits and unnecessarily inflates our error bars for the transit depth. Therefore, we reanalyzed our full dataset and developed a modeling package called EXOMOP that uses the analytic equations of Mandel & Agol (2002) to generate a model transit, the Levenberg-Marquardt non-linear least squares minimization algorithm to find the best fit, the bootstrap Monte Carlo technique to calculate robust errors of the fitted parameters, and the residual permutation “rosary bead” method to access the importance of red noise. From our reanalysis of the data we find that our error bars on the transit depth are not overestimated. We find that our results overlap within errors the short-wavelength observations of de Mooij et al. (2012), but are also consistent with a spectral slope of zero in GJ 1214b in the optical wavelength region. Our observations thus allow for a larger suite of possible atmosphere compositions, including those with a high-molecular-weight and hazes.

Turner, Jake; Teske, J.; Mueller, M.; Griffith, C. A.

2013-06-01

48

An Examination of Possible Gravitational Perturbations in the Transit Timing Variations of Exoplanet WASP-3b  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Maciejewski et al. (2010) claim to have detected a possible sinusoidal variation in the transit timing variations of exoplanet WASP-3b, which is currently the only known planet orbiting the star WASP-3. According to Maciejewski's analysis, this signal might be the consequence of gravitational perturbations caused by a hypothetical second exoplanet in the WASP-3 system. I report five transit timing measurements from the summer of 2010 which provide modest support for Maciejew...

Littlefield, Colin

2011-01-01

49

A Search for Photometric Variability Towards M71 with the Near-Infrared Transiting ExoplanetS Telescope  

CERN Document Server

We present the results of a high-cadence photometric survey of an $11'\\times11'$ field centred on the globular cluster M71, with the Near-Infrared Transiting ExoplanetS Telescope. The aim of our survey is to search for stellar variability and transiting giant exoplanets. This survey differs from previous photometric surveys of M71 in that it is more sensitive to lower amplitude ($\\Delta M\\leq0.02$ mag) and longer period ($P>2$ d) variability than previous work on this cluster. We have discovered $17$ new variable stars towards M71 and confirm the nature of $13$ previously known objects, for which the orbital periods of $7$ are refined or newly determined. Given the photometric precision of our high-cadence survey on the horizontal branch of M71, we confirm the cluster is devoid of RR Lyrae variable stars within the area surveyed. We present new $B$ and $V$ band photometry of the stars in our sample from which we estimate spectral types of the variable objects. We also search our survey data for transiting hot...

McCormac, J; Pollacco, D; Faedi, F; Ramsay, G; Dhillon, V S; Todd, I; Gonzalez, A

2013-01-01

50

AN EFFICIENT AUTOMATED VALIDATION PROCEDURE FOR EXOPLANET TRANSIT CANDIDATES  

Energy Technology Data Exchange (ETDEWEB)

Surveys searching for transiting exoplanets have found many more candidates than they have been able to confirm as true planets. This situation is especially acute with the Kepler survey, which has found over 2300 candidates but has to date confirmed only a small fraction of them as planets. I present here a general procedure that can quickly be applied to any planet candidate to calculate its false positive probability. This procedure takes into account the period, depth, duration, and shape of the signal; the colors of the target star; arbitrary spectroscopic or imaging follow-up observations; and informed assumptions about the populations and distributions of field stars and multiple-star properties. Applying these methods to a sample of known Kepler planets, I demonstrate that many signals can be validated with very limited follow-up observations: in most cases with only a spectrum and an adaptive optics image. Additionally, I demonstrate that this procedure can reliably identify false positive signals. Because of the computational efficiency of this analysis, it is feasible to apply it to all Kepler planet candidates in the near future, and it will streamline the follow-up efforts for Kepler and other current and future transit surveys.

Morton, Timothy D., E-mail: tdm@astro.caltech.edu [Department of Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States)

2012-12-10

51

An Efficient Automated Validation Procedure for Exoplanet Transit Candidates  

Science.gov (United States)

Surveys searching for transiting exoplanets have found many more candidates than they have been able to confirm as true planets. This situation is especially acute with the Kepler survey, which has found over 2300 candidates but has to date confirmed only a small fraction of them as planets. I present here a general procedure that can quickly be applied to any planet candidate to calculate its false positive probability. This procedure takes into account the period, depth, duration, and shape of the signal; the colors of the target star; arbitrary spectroscopic or imaging follow-up observations; and informed assumptions about the populations and distributions of field stars and multiple-star properties. Applying these methods to a sample of known Kepler planets, I demonstrate that many signals can be validated with very limited follow-up observations: in most cases with only a spectrum and an adaptive optics image. Additionally, I demonstrate that this procedure can reliably identify false positive signals. Because of the computational efficiency of this analysis, it is feasible to apply it to all Kepler planet candidates in the near future, and it will streamline the follow-up efforts for Kepler and other current and future transit surveys.

Morton, Timothy D.

2012-12-01

52

Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanets  

CERN Document Server

Infrared transmission and emission spectroscopy of exoplanets, recorded from primary transit and secondary eclipse measurements, indicate the presence of the most abundant carbon and oxygen molecular species (H2O, CH4, CO, and CO2) in a few exoplanets. However, efforts to constrain the molecular abundances to within several orders of magnitude are thwarted by the broad range of degenerate solutions that fit the data. Here we explore, with radiative transfer models and analytical approximations, the nature of the degenerate solution sets resulting from the sparse measurements of "hot Jupiter" exoplanets. As demonstrated with simple analytical expressions, primary transit measurements probe roughly 4 atmospheric scale heights at each wavelength band. Derived mixing ratios from these data are highly sensitive to errors in the radius in planet (at a reference pressure), which are approximately a few percent. For example, an uncertainty of 1% in the radius of a 1000 K and H2-based exoplanet with Jupiter's radius a...

Griffith, Caitlin A

2013-01-01

53

An Efficient Automated Validation Procedure for Exoplanet Transit Candidates  

CERN Multimedia

Surveys searching for transiting exoplanets have found many more candidates than they have been able to confirm as true planets. This situation is especially acute with the Kepler survey, which has found over 2300 candidates but has confirmed only 61 planets to date. I present here a general procedure that can quickly be applied to any planet candidate to calculate its false positive probability. This procedure takes into account the period, depth, duration, and shape of the signal; the colors of the target star; arbitrary spectroscopic or imaging follow-up observations; and informed assumptions about the populations and distributions of field stars and multiple-star properties. I also introduce the concept of the "specific occurrence rate," which allows for the calculation of the FPP without relying on an assumed planet radius function. Applying these methods to a sample of known Kepler planets, I demonstrate that many signals can be validated with very limited follow-up observations: in most cases with only...

Morton, Timothy D

2012-01-01

54

Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanets.  

Science.gov (United States)

Infrared transmission and emission spectroscopy of exoplanets, recorded from primary transit and secondary eclipse measurements, indicate the presence of the most abundant carbon and oxygen molecular species (H2O, CH4, CO and CO2) in a few exoplanets. However, efforts to constrain the molecular abundances to within several orders of magnitude are thwarted by the broad range of degenerate solutions that fit the data. Here, we explore, with radiative transfer models and analytical approximations, the nature of the degenerate solution sets resulting from the sparse measurements of 'hot Jupiter' exoplanets. As demonstrated with simple analytical expressions, primary transit measurements probe roughly four atmospheric scale heights at each wavelength band. Derived mixing ratios from these data are highly sensitive to errors in the radius of the planet at a reference pressure. For example, an uncertainty of 1% in the radius of a 1000?K and H2-based exoplanet with Jupiter's radius and mass causes an uncertainty of a factor of approximately 100-10,000 in the derived gas mixing ratios. The degree of sensitivity depends on how the line strength increases with the optical depth (i.e. the curve of growth) and the atmospheric scale height. Temperature degeneracies in the solutions of the primary transit data, which manifest their effects through the scale height and absorption coefficients, are smaller. We argue that these challenges can be partially surmounted by a combination of selected wavelength sampling of optical and infrared measurements and, when possible, the joint analysis of transit and secondary eclipse data of exoplanets. However, additional work is needed to constrain other effects, such as those owing to planetary clouds and star spots. Given the current range of open questions in the field, both observations and theory, there is a need for detailed measurements with space-based large mirror platforms (e.g. James web space telescope) and smaller broad survey telescopes as well as ground-based efforts. PMID:24664920

Griffith, Caitlin A

2014-04-28

55

THE TRANSIT LIGHT CURVE PROJECT. XII. SIX TRANSITS OF THE EXOPLANET XO-2b  

International Nuclear Information System (INIS)

We present photometry of six transits of the exoplanet XO-2b. By combining the light-curve analysis with theoretical isochrones to determine the stellar properties, we find the planetary radius to be 0.996+0.031 -0.018 R Jup and the planetary mass to be 0.565 ± 0.054 M Jup. These results are consistent with those reported previously, and are also consistent with theoretical models for gas giant planets. The midtransit times are accurate to within 1 minute and are consistent with a constant period. However, the period we derive differs by 2.5? from the previously published period. More data are needed to tell whether the period is actually variable (as it would be in the presence of an additional body) or if the timing errors have been underestimated.

2009-06-01

56

Thermal phase curves of non-transiting terrestrial exoplanets 1. Characterizing atmospheres  

CERN Multimedia

Although transit spectroscopy is a powerful method for studying the composition, thermal properties and dynamics of exoplanet atmospheres, only a few transiting terrestrial exoplanets will be close enough to allow significant transit spectroscopy. Thermal phase curves (variations of the apparent infrared emission of the planet with its orbital phase) have been observed for hot Jupiters in both transiting and non-transiting configurations, and could be observed for hot terrestrial exoplanets. We study the wavelength and phase changes of the thermal emission of a tidally-locked terrestrial planet as atmospheric pressure increases, and address the observability of these multiband phase-curves and the ability to use them to detect atmospheric constituents. We used a 3D climate model (GCM) to simulate the CO2 atmosphere of a terrestrial planet on an 8-day orbit around a M3 dwarf and its apparent infrared emission as a function of its orbital phase. We estimated the signal to photon-noise ratio in narrow bands betw...

Selsis, Franck; Forget, François

2011-01-01

57

C/O Ratios of Stars with Transiting Hot Jupiter Exoplanets  

Science.gov (United States)

The relative abundances of carbon and oxygen have long been recognized as fundamental diagnostics of stellar chemical evolution. Now, the growing number of exoplanet observations enable estimation of these elements in exoplanetary atmospheres. In hot Jupiters, the C/O ratio affects the partitioning of carbon in the major observable molecules, making these elements diagnostic of temperature structure and composition. Here we present measurements of carbon and oxygen abundances in 16 stars that host transiting hot Jupiter exoplanets, and we compare our C/O ratios to those measured in larger samples of host stars, as well as those estimated for the corresponding exoplanet atmospheres. With standard stellar abundance analysis we derive stellar parameters as well as [C/H] and [O/H] from multiple abundance indicators, including synthesis fitting of the [O I] ?6300 line and non-LTE corrections for the O I triplet. Our results, in agreement with recent suggestions, indicate that previously measured exoplanet host star C/O ratios may have been overestimated. The mean transiting exoplanet host star C/O ratio from this sample is 0.54 (C/O? = 0.54), versus previously measured C/Ohost star means of ~0.65-0.75. We also observe the increase in C/O with [Fe/H] expected for all stars based on Galactic chemical evolution; a linear fit to our results falls slightly below that of other exoplanet host star studies but has a similar slope. Though the C/O ratios of even the most-observed exoplanets are still uncertain, the more precise abundance analysis possible right now for their host stars can help constrain these planets' formation environments and current compositions. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Teske, Johanna K.; Cunha, Katia; Smith, Verne V.; Schuler, Simon C.; Griffith, Caitlin A.

2014-06-01

58

Estimations of orbital parameters of exoplanets from transit photometry by using dynamical constraints  

CERN Multimedia

The probability of the detection of Earth-like exoplanets may increase in the near future after the launch of the space missions using the transit photometry as observation method. By using this technique only the semi-major axis of the detected planet can be determined, and there will be no information on the upper limit of its orbital eccentricity. However, the orbital eccentricity is a very important parameter, not only from a dynamical point of view, since it gives also information on the climate and the habitability of the Earth-like planets. In this paper a possible procedure is suggested for confining the eccentricity of an exoplanet discovered by transit photometry if an already known giant planet orbits also in the system.

Sándor, Z

2006-01-01

59

Exploring the Exoplanet Mass/Radius Relationship with the Transit Ephemeris Refinement and Monitoring Survey (TERMS)  

Science.gov (United States)

Transiting planet discoveries have yielded a plethora of information regarding the internal structure and atmospheres of extra-solar planets. These discoveries have been restricted to the low-periastron distance regime due to the bias inherent in the geometric transit probability. Monitoring known radial velocity planets at predicted transit times is a proven method of detecting transits, and presents an avenue through which to explore the mass-radius relationship of exoplanets in new regions of period/periastron space. Here we describe transit window calculations for known radial velocity planets, techniques for refining their transit ephemerides, target selection criteria, and observational methods for obtaining maximum coverage of transit windows. These methods are currently being implemented by the Transit Ephemeris Refinement and Monitoring Survey (TERMS).

Kane, Stephen R.; Ciardi, D.; Fischer, D.; Henry, G.; Howard, A.; Laughlin, G.; Mahadevan, S.; von Braun, K.

2010-01-01

60

Recent Transits of the Super-Earth Exoplanet GJ 1214b  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report recent ground-based photometry of the transiting super-Earth exoplanet GJ1214b at several wavelengths, including the infrared near 1.25 microns (J-band). We observed a J-band transit with the FLAMINGOS infrared imager and the 2.1-meter telescope on Kitt Peak, and we observed several optical transits using a 0.5-meter telescope on Kitt Peak and the 0.36-meter Universidad de Monterrey Observatory telescope. Our high-precision J-band observations exploit the brightnes...

Sada, Pedro V.; Deming, Drake; Jackson, Brian; Jennings, Donald E.; Peterson, Steven W.; Haase, Flynn; Bays, Kevin; O Gorman, Eamon; Lundsford, Alan

2010-01-01

 
 
 
 
61

Stellar companions to exoplanet host stars: Lucky Imaging of transiting planet hosts  

CERN Document Server

Observed properties of stars and planets in binary/multiple star systems provide clues to planet formation and evolution. We extended our survey for visual stellar companions to the hosts of transiting exoplanets by 21 stars, using the Lucky Imaging technique with the two AstraLux instruments: AstraLux Norte at the Calar Alto 2.2-m telescope, and AstraLux Sur at the ESO 3.5-m New Technology Telescope at La Silla. We present observations of two previously unknown binary candidate companions, to the transiting planet host stars HAT-P-8 and WASP-12, and derive photometric and astrometric properties of the companion candidates. The common proper motions of the previously discovered candidate companions with the exoplanet host stars TrES-4 and WASP-2 are confirmed from follow-up observations. A Bayesian statistical analysis of 31 transiting exoplanet host stars observed with AstraLux suggests that the companion star fraction of planet hosts is not significantly different from that of solar-type field stars, but th...

Bergfors, Carolina; Daemgen, Sebastian; Biller, Beth; Hippler, Stefan; Janson, Markus; Kudryavtseva, Natalia; Geißler, Kerstin; Henning, Thomas; Köhler, Rainer

2012-01-01

62

A Method to Identify the Boundary Between Rocky and Gaseous Exoplanets from Tidal Theory and Transit Durations  

CERN Document Server

The determination of an exoplanet as rocky is critical for the assessment of planetary habitability. Observationally, the number of small-radius, transiting planets with accompanying mass measurements is insufficient for a robust determination of the transitional mass or radius. Theoretically, models predict that rocky planets can grow large enough to become gas giants when they reach ~10 Earth-masses, but the transitional mass remains unknown. Here I show how transit data, interpreted in the context of tidal theory, can reveal the critical radius that separates rocky and gaseous exoplanets. Standard tidal models predict that rocky exoplanets' orbits are tidally circularized much more rapidly than gaseous bodies', suggesting the former will tend to be found on circular orbits at larger semi-major axes than the latter. Well-sampled transits can provide a minimum eccentricity of the orbit, allowing a measurement of this differential circularization. I show that this effect should be present in the data from the...

Barnes, Rory

2013-01-01

63

Influence of stellar variability on the determination of the radius during a transit of an exoplanet  

Directory of Open Access Journals (Sweden)

Full Text Available Stellar variability can affect the estimate of an exoplanet radius measured during a transit. We developed a transit light curve model which includes stellar spots. It appears that, if spectro-photometric technique is used, spots and faculae have to be considered to conclude on atmospheric detection and characterization. When using a model including spots, characterization of Hot-Jupiter atmosphere around active stars is possible with this technique, provided a signal to noise ratio up to 105. For Earth-size planets a long-term parallel photometric follow up monitoring the stellar activity is required to compensate the error due to the stellar variability.

Désert J.-M.

2011-07-01

64

RATS: an Italian project for Exoplanets Transit Search  

Science.gov (United States)

The RATS (RAdial velocity and Transit Search) project is a collaboration among INAF sections of Catania, Napoli, Padova and Palermo and the Physics and Astronomy departments of Padova University. The main goal of the project is to discover at least 10 new planets transiting the host star using a suitable automatic data-reduction pipeline developed for RATS.

Granata, V.; Claudi, R. U.; Baruffolo, A.; Contri, L.; Montalto, M.; Piotto, G. P.; Bruno, P.; Scuderi, S.

2007-07-01

65

Investigating Close-in Exoplanets through Transit Observations  

CERN Document Server

Through the international collaborators, we recently established a network of existing and working meter-class telescopes to look for planetary transit events. As a first step, we focus on the TrES3 system, and conclude that there could be some level of transit timing variations.

Jiang, Ing-Guey; Thakur, Parijat; Chien, Ping; Lin, Yi-Ling; Wu, Yu-Ting; Chen, Hong-Yu; Sun, Zhao; Ji, Jianghui

2013-01-01

66

ASTEP South: An Antarctic Search for Transiting ExoPlanets around the celestial South pole  

Digital Repository Infrastructure Vision for European Research (DRIVER)

ASTEP South is the first phase of the ASTEP project (Antarctic Search for Transiting ExoPlanets). The instrument is a fixed 10 cm refractor with a 4kx4k CCD camera in a thermalized box, pointing continuously a 3.88° x 3.88° field of view centered on the celestial South pole. ASTEP South became fully functional in June 2008 and obtained 1592 hours of data during the 2008 Antarctic winter. The data are of good quality but the analysis has to account for changes in the point spread function du...

Crouzet, Nicolas; Guillot, Tristan; Agabi, Karim; Rivet, Jean-pierre; Bondoux, Erick; Challita, Zalpha; Fantei?-caujolle, Yan; Fressin, Franc?ois; Me?karnia, Djamel; Schmider, Franc?ois-xavier; Valbousquet, Franck; Blazit, Alain; Bonhomme, Serge; Abe, Lyu; Daban, Jean-baptiste

2009-01-01

67

H{alpha} ABSORPTION IN TRANSITING EXOPLANET ATMOSPHERES  

Energy Technology Data Exchange (ETDEWEB)

Absorption of stellar H{alpha} by the upper atmosphere of the planet HD 189733b has recently been detected by Jensen et al. Motivated by this observation, we have developed a model for atomic hydrogen in the n = 2 state and compared the resulting H{alpha} line profile to the observations. The model atmosphere is in hydrostatic balance, as well as thermal and photoionization equilibrium. Collisional and radiative transitions are included in the determination of the n = 2 state level population. We find that H{alpha} absorption is dominated by an optical depth {tau} {approx} 1 shell, composed of hydrogen in the metastable 2s state that is located below the hydrogen ionization layer. The number density of the 2s state within the shell is found to vary slowly with radius, while that of the 1s state falls rapidly. Thus while the Ly{alpha} absorption, for a certain wavelength, occurs inside a relatively well defined impact parameter, the contribution to H{alpha} absorption is roughly uniform over the entire atomic hydrogen layer. The model can approximately reproduce the observed Ly{alpha} and H{alpha} integrated transit depths for HD 189733b by using an ionization rate enhanced over that expected for the star by an order of magnitude. For HD 209458b, we are unable to explain the asymmetric H{alpha} line profile observed by Jensen et al., as the model produces a symmetric line profile with transit depth comparable to that of HD 189733b. In an appendix, we study the effect of the stellar Ly{alpha} absorption on the net cooling rate.

Christie, Duncan; Arras, Phil; Li Zhiyun, E-mail: dac5zm@virginia.edu, E-mail: pla7y@virginia.edu, E-mail: zl4h@virginia.edu [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States)

2013-08-01

68

Estimating transiting exoplanet masses from precise optical photometry  

CERN Document Server

We present a theoretical analysis of the optical light curves (LCs) for short-period high-mass transiting extrasolar planet systems. Our method considers the primary transit, the secondary eclipse, and the overall phase shape of the LC between the occultations. Phase variations arise from (i) reflected and thermally emitted light by the planet, (ii) the ellipsoidal shape of the star due to the gravitational pull of the planet, and (iii) the Doppler shift of the stellar light as the star orbits the center of mass of the system. Our full model of the out-of-eclipse variations contains information about the planetary mass, orbital eccentricity, the orientation of periastron and the planet's albedo. For a range of hypothetical systems we demonstrate that the ellipsoidal variations (ii.) can be large enough to be distinguished from the remaining components and that this effect can be used to constrain the planet's mass. To detect the ellipsoidal variations, the LC requires a minimum precision of 10-4, which coinci...

Mislis, D; Schmitt, J H M M; Hodgkin, S

2011-01-01

69

How Close are the Nearest Transiting Exoplanet Systems? Updated Planet Occurrence Rates from Kepler & Implications for TESS  

Science.gov (United States)

Here we consider the most likely distances and apparent magnitudes of the nearest transiting exoplanet systems. In preparation for the next-generation of exoplanet surveys, we would like to know the properties of these systems in order to optimize survey strategies and plan follow-up observations. We begin by populating a catalog of nearby stars with planets using occurrence rates estimated from Kepler. For FGK stars, we rely on previously published estimates of the planet occurrence rate. For smaller stars, we determine the planet occurrence rate by using our own planet detection pipeline to search for additional planets around small Kepler target stars. We empirically measure the planet detection threshold of our pipeline by injecting and recovering transits. After assigning planets to stars, we query the resulting planet catalog to determine the properties of the nearest and brightest transiting exoplanets. We will discuss the implications of this simulated planet population for exoplanet surveys such as TESS, PLATO, MEarth, CARMENES, CHEOPS, ExoplanetSat, ExTrA, HPF, SPECULOOS, and SPIROU. We also consider the observing resources that will be required to follow up these systems with extremely large ground-based telescopes like the GMT, TMT, and E-ELT.

Dressing, Courtney D.; Charbonneau, David; Sullivan, Peter; Winn, Joshua N.

2014-06-01

70

Astrophysical false positives in exoplanet transit surveys: why do we need bright stars ?  

CERN Document Server

Astrophysical false positives that mimic planetary transit are one of the main limitation to exoplanet transit surveys. In this proceeding, we review the issue of the false positive in transit survey and the possible complementary observations to constrain their presence. We also review the false-positive rate of both Kepler and CoRoT missions and present the basics of the planet-validation technique. Finally, we discuss the interest of observing bright stars, as PLATO 2.0 and TESS will do, in the context of the false positives. According to simulations with the Besan\\c{c}on galactic model, we find that PLATO 2.0 is expected to have less background false positives than Kepler, and thus an even lower false-positive rate.

Santerne, A; Almenara, J -M; Lethuillier, A; Deleuil, M; Moutou, C

2013-01-01

71

Astrophysical false positives in exoplanet transit surveys: why do we need bright stars ?  

Science.gov (United States)

Astrophysical false positives that mimic planetary transit are one of the main limitation to exoplanet transit surveys. In this proceeding, we review the issue of the false positive in transit survey and the possible complementary observations to constrain their presence. We also review the false-positive rate of both Kepler and CoRoT missions and present the basics of the planet-validation technique. Finally, we discuss the interest of observing bright stars, as PLATO 2.0 and TESS will do, in the context of the false positives. According to simulations with the Besançon galactic model, we find that PLATO 2.0 is expected to have less background false positives than Kepler, and thus an even lower false-positive rate.

Santerne, A.; Díaz, R. F.; Almenara, J.-M.; Lethuillier, A.; Deleuil, M.; Moutou, C.

2013-11-01

72

The Exoplanet Orbit Database  

CERN Document Server

We present a database of well determined orbital parameters of exoplanets. This database comprises spectroscopic orbital elements measured for 421 planets orbiting 357 stars from radial velocity and transit measurements as reported in the literature. We have also compiled fundamental transit parameters, stellar parameters, and the method used for the planets discovery. This Exoplanet Orbit Database includes all planets with robust, well measured orbital parameters reported in peer-reviewed articles. The database is available in a searchable, filterable, and sortable form on the Web at http://exoplanets.org through the Exoplanets Data Explorer Table, and the data can be plotted and explored through the Exoplanets Data Explorer Plotter. We use the Data Explorer to generate publication-ready plots giving three examples of the signatures of exoplanet migration and dynamical evolution: We illustrate the character of the apparent correlation between mass and period in exoplanet orbits, the selection different biase...

Wright, Jason T; Marcy, Geoffrey W; Han, Eunkyu; Feng, Ying; Johnson, John Asher; Howard, Andrew W; Valenti, Jeff A; Anderson, Jay; Piskunov, Nikolai

2010-01-01

73

A new look at the Spitzer primary transit observations of the exoplanet HD189733b  

Science.gov (United States)

New blind source separation techniques are used to analyse uniformly eight primary transit lightcurves of the exoplanet HD189733b recorded with the infrared camera IRAC on board the Spitzer Space Telescope at 3.6?m. The observations were performed between 2006 and 2011: two of them were obtained in the"Cold Spitzer" regime, the others were taken in the "Warm Spitzer" period. The techniques we used to process the data are based on an Independent Component Analysis (ICA) approach, i.e. a computational method to disentangle the 'original source signals' from a set of observations/ recordings in which they are mixed. ICA assumes only the mutual statistical independence and the non-gaussianity of the source signals. Our objective was to extract the transit components by removing instrumental systematic effects and possibly other sources of astrophysical noise, such as background and stellar activity. The novelty of the algorithms used is their ability to extract the exoplanet signal in a single observation. In this presentation we will present the results obtained, detail the methods adopted and critically discuss the conclusions of our work by comparing said results to the ones obtained in the literature.

Morello, G.; Peres, G.; Micela, G.; Waldmann, I. P.; Tinetti, G.; Howarth, I. D.

2013-09-01

74

Transits of Venus and Mercury: Exoplanet Analogs in Our Solar System  

Science.gov (United States)

Since Johannes Kepler's predictions of transits of Mercury and Venus in 1631, and observations by Jeremiah Horrocks and William Crabtree of the 1639 transit of Venus, only 5 other transits of Venus have been observed: in 1761 and 1769, 1874 and 1882, and 2004. Expeditions were sent all over the world for the 18th and 19th century transits to follow the methods of Halley and others to determine the Astronomical Unit, giving the size and scale of the solar system, arguably the most important problem in astronomy for centuries. I will discuss how the infamous black-drop effect bedeviled astronomers in that quest for an accurate A.U., and how Glenn Schneider and I explained the effect through satellite observations of transits of Mercury, showing that it was not simply caused by the Cytherean atmosphere. During the 2004 transit, we worked with Richard Willson of ACRIMsat to detect the 0.1% drop in the Total Solar Irradiance, showing the effect of solar limb darkening, positioning such observations of transits of Venus and of Mercury as analogs to exoplanet transits. Our observations of the atmosphere of Venus with NASA's Transition Region and Coronal Explorer in 2004 led us to plan extensive observations of Venus's atmosphere and other phenomena during the June 5, 2012, transit of Venus, the last to be visible from Earth until 2117. We will have used NASA's Solar Dynamics Observatory, Hinode, ACRIMsat, and other spacecraft, and ground-based solar telescopes at Sacramento Peak, Kitt Peak, Big Bear, and Haleakala to observe the transit; I hope to give preliminary reports on these observations during this talk. Further, I will discuss the plans of Ehrenreich and colleagues for Hubble observations of this transit and our hopes of detecting transits of Venus and Earth as seen from Jupiter and Saturn over the next few years.

Pasachoff, Jay M.

2012-05-01

75

First Evidence of a Retrograde Orbit of Transiting Exoplanet HAT-P-7b  

CERN Document Server

We present the first evidence of a retrograde orbit of the transiting exoplanet HAT-P-7b. The discovery is based on a measurement of the Rossiter-McLaughlin effect with the Subaru HDS during a transit of HAT-P-7b, occured on UT 2008 May 30. Our model shows that the spin-orbit alignment angle of this planet is $\\lambda = -132.6^{\\circ} (+12.6^{\\circ}, -21.5^{\\circ})$. The existence of such a retrograde planet had been predicted by recent planetary migration models considering planet-planet scattering processes or the Kozai migration. Our finding provides an important milestone that supports such dynamic migration theories.

Narita, Norio; Hirano, Teruyuki; Tamura, Motohide

2009-01-01

76

Classical and relativistic long-term time variations of some observables for transiting exoplanets  

CERN Document Server

We analytically work out the long-term, i.e. averaged over one orbital revolution, time variations of some direct observable quantities Y induced by classical and general relativistic dynamical perturbations of the two-body pointlike Newtonian acceleration in the case of transiting exoplanets moving along elliptic orbits. More specifically, the observables $Y$ with which we deal are the transit duration, the radial velocity and the time interval between primary and secondary eclipses. The dynamical effects considered are the centrifugal oblateness of both the star and the planet, their tidal bulges mutually raised on each other, a distant third body X, and general relativity (both Schwarzschild and Lense-Thirring). We take into account the effects due to the perturbations of all the Keplerian orbital elements involved in a consistent and uniform way. First, we explicitly compute their instantaneous time variations due to the dynamical effects considered and plug them in the general expression for the instanta...

Iorio, Lorenzo

2010-01-01

77

Multi-band transit observations of the TrES-2b exoplanet  

CERN Document Server

We present a new data set of transit observations of the TrES-2b exoplanet taken in spring 2009, using the 1.2m Oskar-Luhning telescope (OLT) of Hamburg Observatory and the 2.2m telescope at Calar Alto Observatory using BUSCA (Bonn University Simultaneous CAmera). Both the new OLT data, taken with the same instrumental setup as our data taken in 2008, as well as the simultaneously recorded multicolor BUSCA data confirm the low inclination values reported previously, and in fact suggest that the TrES-2b exoplanet has already passed the first inclination threshold (i_min,1 = 83.417) and is not eclipsing the full stellar surface any longer. Using the multi-band BUSCA data we demonstrate that the multicolor light curves can be consistently fitted with a given set of limb darkening coefficients without the need to adjust these coefficients, and further, we can demonstrate that wavelength dependent stellar radius changes must be small as expected from theory. Our new observations provide further evidence for a chan...

Mislis, D; Schmitt, J H M M; Cordes, O; Reif, K

2009-01-01

78

Directly Imaged L-T Transition Exoplanets in the Mid-Infrared  

CERN Document Server

Gas-giant planets emit a large fraction of their light in the mid-infrared ($\\gtrsim$3$\\mu \\rm m$), where photometry and spectroscopy are critical to our understanding of the bulk properties of extrasolar planets. Of particular importance are the L and M-band atmospheric windows (3-5$\\mu \\rm m$), which are the longest wavelengths currently accessible to ground-based, high-contrast imagers. We present binocular LBT AO images of the HR 8799 planetary system in six narrow-band filters from 3-4$\\mu \\rm m$, and a Magellan AO image of the 2M1207 planetary system in a broader 3.3$\\mu \\rm m$ band. These systems encompass the five known exoplanets with luminosities consistent with L$\\rightarrow$T transition brown dwarfs. Our results show that the exoplanets are brighter and have shallower spectral slopes than equivalent temperature brown dwarfs in a wavelength range that contains the methane fundamental absorption feature. For 2M1207 b, we find that thick clouds and non-equilibrium chemistry caused by vertical mixing ...

Skemer, Andrew J; Hinz, Philip M; Morzinski, Katie M; Skrutskie, Michael F; Leisenring, Jarron M; Close, Laird M; Saumon, Didier; Bailey, Vanessa P; Briguglio, Runa; Defrere, Denis; Esposito, Simone; Follette, Katherine B; Hill, John M; Males, Jared R; Puglisi, Alfio; Rodigas, Timothy J; Xompero, Marco

2013-01-01

79

Colour-magnitude diagrams of transiting Exoplanets - II. A larger sample from photometric distances  

CERN Document Server

Colour-magnitude diagrams form a traditional way of presenting luminous objects in the Universe and compare them to each others. Here, we estimate the photometric distance of 44 transiting exoplanetary systems. Parallaxes for seven systems confirm our methodology. Combining those measurements with fluxes obtained while planets were occulted by their host stars, we compose colour-magnitude diagrams in the near and mid-infrared. When possible, planets are plotted alongside very low-mass stars and field brown dwarfs, who often share similar sizes and equilibrium temperatures. They offer a natural, empirical, comparison sample. We also include directly imaged exoplanets and the expected loci of pure blackbodies. Irradiated planets do not match blackbodies; their emission spectra are not featureless. For a given luminosity, hot Jupiters' daysides show a larger variety in colour than brown dwarfs do and display an increasing diversity in colour with decreasing intrinsic luminosity. The presence of an extra absorben...

Triaud, Amaury H M J; Smalley, Barry; Gillon, Michael

2014-01-01

80

Transiting exoplanets from the CoRoT space mission. XXIII. CoRoT-21b: a doomed large Jupiter around a faint subgiant star  

Digital Repository Infrastructure Vision for European Research (DRIVER)

CoRoT-21, a F8IV star of magnitude V = 16 mag, was observed by the space telescope CoRoT during the Long Run 01 (LRa01) in the first winter field (constellation Monoceros) from October 2007 to March 2008. Transits were discovered during the light curve processing. Radial velocity follow-up observations, however, were performed mainly by the 10-m Keck telescope in January 2010. The companion CoRoT-21b is a Jupiter-like planet of 2.26 ± 0.33 Jupiter masses and 1.30 ± 0.14 Jupiter radii in an ...

2012-01-01

 
 
 
 
81

An unconsidered configuration of astrophysical false positives in exoplanet-transit surveys  

CERN Document Server

We investigate in this paper the astrophysical false-positive configuration in exoplanet-transit surveys that involves eclipsing binaries and giant planets which present only a secondary eclipse, as seen from the Earth. To test how an eclipsing binary configuration can mimic a planetary transit, we generate synthetic light curve of three examples of secondary-only eclipsing binary systems that we fit with a circular planetary model. Then, to evaluate its occurrence we model a population of binaries in double and triple system based on binary statistics and occurrence. We find that 0.061% +/- 0.017% of main-sequence binary stars are secondary-only eclipsing binaries mimicking a planetary transit candidate down to the size of the Earth. We then evaluate the occurrence that an occulting-only giant planet can mimic an Earth-like planet or even smaller planet. We find that 0.009% +/- 0.002% of stars harbor a giant planet that present only the secondary transit. Occulting-only giant planets mimic planets smaller th...

Santerne, A; Díaz, R F; Figueira, P; Almenara, J -M; Santos, N C

2013-01-01

82

Accretion of Jupiter-mass Planets in the Limit of Vanishing Viscosity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the core-accretion model the nominal runaway gas-accretion phase brings most planets to multiple Jupiter masses. However, known giant planets are predominantly Jupiter-mass bodies. Obtaining longer timescales for gas accretion may require using realistic equations of states, or accounting for the dynamics of the circumplanetary disk (CPD) in low-viscosity regime, or both. Here we explore the second way using global, three-dimensional isothermal hydrodynamical simulations ...

Szula?gyi, J.; Morbidelli, A.; Crida, A.; Masset, F.

2013-01-01

83

ASTEROSEISMOLOGY OF THE TRANSITING EXOPLANET HOST HD 17156 WITH HUBBLE SPACE TELESCOPE FINE GUIDANCE SENSOR  

International Nuclear Information System (INIS)

Observations conducted with the Fine Guidance Sensor on the Hubble Space Telescope (HST) providing high cadence and precision time-series photometry were obtained over 10 consecutive days in 2008 December on the host star of the transiting exoplanet HD 17156b. During this time, 1.0 x 1012 photons (corrected for detector dead time) were collected in which a noise level of 163 parts per million per 30 s sum resulted, thus providing excellent sensitivity to the detection of the analog of the solar 5-minute p-mode oscillations. For HD 17156, robust detection of p modes supports the determination of the stellar mean density of (?*) = 0.5301 ± 0.0044 g cm-3 from a detailed fit to the observed frequencies of modes of degree l = 0, 1, and 2. This is the first star for which the direct determination of (?*) has been possible using both asteroseismology and detailed analysis of a transiting planet light curve. Using the density constraint from asteroseismology, and stellar evolution modeling results in M* = 1.285 ± 0.026 Msun, R* = 1.507 ± 0.012 Rsun, and a stellar age of 3.2 ± 0.3 Gyr.

2011-01-01

84

A New Look at Spitzer Primary Transit Observations of the Exoplanet HD 189733b  

Science.gov (United States)

Blind source separation techniques are used to reanalyze two exoplanetary transit light curves of the exoplanet HD 189733b recorded with the IR camera IRAC on board the Spitzer Space Telescope at 3.6 ?m during the "cold" era. These observations, together with observations at other IR wavelengths, are crucial to characterize the atmosphere of the planet HD 189733b. Previous analyses of the same data sets reported discrepant results, hence the necessity of the reanalyses. The method we used here is based on the Independent Component Analysis (ICA) statistical technique, which ensures a high degree of objectivity. The use of ICA to detrend single photometric observations in a self-consistent way is novel in the literature. The advantage of our reanalyses over previous work is that we do not have to make any assumptions on the structure of the unknown instrumental systematics. Such "admission of ignorance" may result in larger error bars than reported in the literature, up to a factor 1.6. This is a worthwhile tradeoff for much higher objectivity, necessary for trustworthy claims. Our main results are (1) improved and robust values of orbital and stellar parameters, (2) new measurements of the transit depths at 3.6 ?m, (3) consistency between the parameters estimated from the two observations, (4) repeatability of the measurement within the photometric level of ~2 × 10–4 in the IR, and (5) no evidence of stellar variability at the same photometric level within one year.

Morello, G.; Waldmann, I. P.; Tinetti, G.; Peres, G.; Micela, G.; Howarth, I. D.

2014-05-01

85

The contribution of secondary eclipses as astrophysical false positives to exoplanet transit surveys  

Science.gov (United States)

We investigate the astrophysical false-positive configuration in exoplanet-transit surveys. It involves eclipsing binaries and giant planets that present only a secondary eclipse, as seen from the Earth. To test how an eclipsing binary configuration can mimic a planetary transit, we generated synthetic light curves of three examples of secondary-only eclipsing binary systems that we fit with a circular planetary model. Then, to evaluate its occurrence we modeled a population of binaries in double and triple systems based on binary statistics and occurrence. We find that 0.061% ± 0.017% of main-sequence binary stars are secondary-only eclipsing binaries that mimics a planetary transit candidate with a size down to the size of the Earth. We then evaluate the occurrence that an occulting-only giant planet can mimic an Earth-like planet or even a smaller one. We find that 0.009% ± 0.002% of stars harbor a giant planet that only presents the secondary transit. Occulting-only giant planets mimic planets that are smaller than the Earth, and they are in the scope of space missions like Kepler and PLATO. We estimate that up to 43.1 ± 5.6 Kepler objects of interest can be mimicked by this configuration of false positives, thereby re-evaluating the global false-positive rate of the Kepler mission from 9.4 ± 0.9% to 11.3 ± 1.1%. We note, however, that this new false-positive scenario occurs at relatively long orbital periods compared with the median period of Kepler candidates.

Santerne, A.; Fressin, F.; Díaz, R. F.; Figueira, P.; Almenara, J.-M.; Santos, N. C.

2013-09-01

86

Formation, evolution and multiplicity of brown dwarfs and giant exoplanets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This proceeding summarises the talk of the awardee of the Spanish Astronomical Society award to the the best Spanish thesis in Astronomy and Astrophysics in the two-year period 2006-2007. The thesis required a tremendous observational effort and covered many different topics related to brown dwarfs and exoplanets, such as the study of the mass function in the substellar domain of the young sigma Orionis cluster down to a few Jupiter masses, the relation between the cluster s...

Caballero, Jose A.

2008-01-01

87

A new look at Spitzer primary transit observations of the exoplanet HD189733b  

CERN Multimedia

Blind source separation techniques are used to reanalyse two exoplanetary transit lightcurves of the exoplanet HD189733b recorded with the IR camera IRAC on board the Spitzer Space Telescope at 3.6$\\mu$m during the "cold" era. These observations, together with observations at other IR wavelengths, are crucial to characterise the atmosphere of the planet HD189733b. Previous analyses of the same datasets reported discrepant results, hence the necessity of the reanalyses. The method we used here is based on the Independent Component Analysis (ICA) statistical technique, which ensures a high degree of objectivity. The use of ICA to detrend single photometric observations in a self-consistent way is novel in the literature. The advantage of our reanalyses over previous work is that we do not have to make any assumptions on the structure of the unknown instrumental systematics. Such "admission of ignorance" may result in larger error bars than reported in the literature, up to a factor $1.6$. This is a worthwhile t...

Morello, Giuseppe; Tinetti, Giovanna; Peres, Giovanni; Micela, Giuseppina; Howarth, Ian D

2014-01-01

88

Catalog of Nearby Exoplanets  

CERN Multimedia

We present a catalog of nearby exoplanets, available at http://exoplanets.org and ApJ 646, 505 (published version available at the link above). It contains the 172 known low mass companions with orbits established through radial velocity and transit measurements around stars within 200 pc. We include 5 previously unpublished exoplanets orbiting the stars HD 11964, HD 66428, HD 99109, HD 107148, and HD 164922. We update orbits for 90 additional exoplanets including many whose orbits have not been revised since their announcement, and include radial velocity time series from the Lick, Keck, and Anglo-Australian Observatory planet searches. Both these new and previously published velocities are more precise here due to improvements in our data reduction pipeline, which we applied to archival spectra. We present a brief summary of the global properties of the known exoplanets, including their distributions of orbital semimajor axis, minimum mass, and orbital eccentricity.

Butler, R P; Marcy, G W; Fischer, D A; Vogt, S S; Tinney, C G; Jones, H R A; Carter, B D; Johnson, J A; McCarthy, C; Penny, A J

2006-01-01

89

SOPHIE velocimetry of kepler transit candidates:XI KOI-142c: first radial velocity confirmation of a non-transiting exoplanet discovered by transit timing  

CERN Document Server

The exoplanet KOI-142b (Kepler-88) shows transit timing variations (TTVs) with a semi-amplitude of $\\sim 12\\,$ hours, earning the nickname of king of transit variations. Only the transit of the planet b was detected in the Kepler data with an orbital period of $\\sim 10.92\\,$ days and a radius of $\\sim 0.36$ RJup. The TTVs together with the transit duration variations (TDVs) of KOI-142b were analysed by Nesvorny et al 2013 who found a unique solution for a companion perturbing planet. The authors predicted an outer non-transiting companion, KOI-142c, with a mass of $0.626\\pm 0.03$ MJup and a period of $22.3397^{+0.0021}_{-0.0018}\\,$days, and hence close to the 2:1 mean-motion resonance with the inner transiting planet. We report independent confirmation of KOI-142c using radial velocity observations with the SOPHIE spectrograph at the Observatoire de Haute-Provence. We derive an orbital period of $22.10 \\pm 0.25\\,$days and a minimum planetary mass of $0.76^{+0.32}_{0.16}\\,$ MJup, both in good agreement with th...

Barros, S C C; Santerne, A; Bruno, G; Deleuil, M; Almenara, J M; Bonomo, A S; Bouchy, F; Damian, C; Hebrard, G; Montagnier, G; Moutou, C; 2,

2013-01-01

90

GTC OSIRIS transiting exoplanet atmospheric survey: detection of sodium in XO-2b from differential long-slit spectroscopy  

CERN Document Server

We present two transits of the hot-Jupiter exoplanet XO-2b using the Gran Telescopio Canarias (GTC). The time series observations were performed using long-slit spectroscopy of XO-2 and a nearby reference star with the OSIRIS instrument, enabling differential specrophotometric transit lightcurves capable of measuring the exoplanet's transmission spectrum. Two optical low-resolution grisms were used to cover the optical wavelength range from 3800 to 9300{\\AA}. We find that sub-mmag level slit losses between the target and reference star prevent full optical transmission spectra from being constructed, limiting our analysis to differential absorption depths over ~1000{\\AA} regions. Wider long slits or multi-object grism spectroscopy with wide masks will likely prove effective in minimising the observed slit-loss trends. During both transits, we detect significant absorption in the planetary atmosphere of XO-2b using a 50{\\AA} bandpass centred on the Na I doublet, with absorption depths of Delta(R_pl/R_star)^2=0...

Sing, D K; Lopez-Morales, M; Pont, F; Désert, J -M; Ehrenreich, D; Wilson, P A; Ballester, G E; Fortney, J J; Etangs, A Lecavelier des; Vidal-Madjar, A

2012-01-01

91

The NASA Exoplanet Archive  

Science.gov (United States)

The NASA Exoplanet Archive is an online service that compiles and correlates astronomical information on extra solar planets and their host stars. The data in the archive include exoplanet parameters (such as orbits, masses, and radii), associated data (such as published radial velocity curves, photometric light curves, images, and spectra), and stellar parameters (such as magnitudes, positions, and temperatures). All the archived data are linked to the original literature reference.The archive provides tools to work with these data, including interactive tables (with plotting capabilities), interactive light curve viewer, periodogram service, transit and ephemeris calculator, and application program interface.The NASA Exoplanet Archive is the U.S. portal to the public CoRoT mission data for both the Exoplanet and Asteroseismology data sets. The NASA Exoplanet Archive also serves data related to Kepler Objects of Interest (Planet Candidates and the Kepler False Positives, KOI) in an integrated and interactive table containing stellar and transit parameters. In support of the Kepler Extended Mission, the NASA Exoplanet Archive will host transit modeling parameters, centroid results, several statistical values, and summary and detailed reports for all transit-like events identified by the Kepler Pipeline. To access this information visit us at: http://exoplanetarchive.ipac.caltech.edu

Ramirez, Solange; Akeson, R. L.; Ciardi, D.; Kane, S. R.; Plavchan, P.; von Braun, K.; NASA Exoplanet Archive Team

2013-01-01

92

The Transit Light Curve Project. VII. The Not-So-Bloated Exoplanet HAT-P-1b  

CERN Multimedia

We present photometry of the G0 star HAT-P-1 during six transits of its close-in giant planet, and we refine the estimates of the system parameters. Relative to Jupiter's properties, HAT-P-1b is 1.20 +/- 0.05 times larger and its surface gravity is 2.7 +/- 0.2 times weaker. Although it remains the case that HAT-P-1b is among the least dense of the known sample of transiting exoplanets, its properties are in accord with previously published models of strongly irradiated, coreless, solar-composition giant planets. The times of the transits have a typical accuracy of 1 min and do not depart significantly from a constant period.

Winn, Joshua N; Bakos, Gaspar A; Pal, Andras; Johnson, John Asher; Williams, Peter K G; Shporer, Avi; Mazeh, Tsevi; Fernandez, Jose; Latham, David W

2007-01-01

93

SOPHIE velocimetry of Kepler transit candidates. X. KOI-142 c: first radial velocity confirmation of a non-transiting exoplanet discovered by transit timing  

Science.gov (United States)

The exoplanet KOI-142b (Kepler-88b) shows transit timing variations (TTVs) with a semi-amplitude of ~12 h, which earned it the nickname "king of transit variations". Only the transit of planet b was detected in the Kepler data with an orbital period of ~10.92 days and a radius of ~0.36 RJup. The TTVs together with the transit duration variations of KOI-142b were analysed recently, finding a unique solution for a companion-perturbing planet. An outer non-transiting companion was predicted, KOI-142c, with a mass of 0.626 ± 0.03 MJup and a period of 22.3397-0.0018+0.0021 days, which is close to the 2:1 mean-motion resonance with the inner transiting planet. We report an independent confirmation of KOI-142c using radial velocity observations with the SOPHIE spectrograph at the Observatoire de Haute-Provence. We derive an orbital period of 22.10 ± 0.25 days and a minimum planetary mass of 0.760.16+0.32 MJup, both in good agreement with the predictions by previous transit timing analysis. Therefore, this is the first radial velocity confirmation of a non-transiting planet discovered with TTVs, providing an independent validation of the TTVs technique. Based on observations collected with the NASA Kepler satellite and with the SOPHIE spectrograph on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS), France.Tables 2 and 3 are available in electronic form at http://www.aanda.org

Barros, S. C. C.; Díaz, R. F.; Santerne, A.; Bruno, G.; Deleuil, M.; Almenara, J.-M.; Bonomo, A. S.; Bouchy, F.; Damiani, C.; Hébrard, G.; Montagnier, G.; Moutou, C.

2014-01-01

94

Constraining the Magnetic Fields of Transiting Exoplanets through Ground-based Near-UV Observations  

Science.gov (United States)

We observed the primary transits of the exoplanets CoRoT-1b, HAT-P-1b, HAT-P-13b, HAT-P-22b, TrES-2b, TrES-4b, WASP-12b, WASP-33b, WASP-44b, WASP-48b, and WASP77A-b in the near-ultraviolet photometric band in an attempt to detect their magnetic fields and update their planetary parameters. Vidotto et al. (2011) suggest that the magnetic fields of these targets could be constrained if their near-UV light curves show an early ingress compared to their optical light curves, while their egress remain unaffected. We do not observe this effect in any of our targets, however, we have determined an upper limit on their magnetic field strengths. Our results are consistent with observations of TrES-3b and HAT-P-16b which both have had upper limits on their magnetic fields found using this method. We find abnormally low field strengths for all our targets. Due to this result we advocate for follow-up studies on the magnetic fields of all our targets using other detection methods (such as radio emission and magnetic star-planet interactions) and other telescopes capable of achieving a better near-UV cadence to verify our findings and the techniques of Vidotto et al. (2011). We find that the near-UV planetary radii of all our targets are consistent within error of their optical radii. Our data includes the only published near-UV light curves of CoRoT-1b, HAT-P-1b, HAT-P-13b, HAT-P-22b, TrES-2b, TrES-4b, WASP-33b, WASP-44b, WASP-48b, and WASP77A-b. We used an automated reduction pipeline, ExoDRPL, to perform aperture photometry on our data. In addition, we developed a modeling package called EXOMOP that utilizes the Levenberg-Marquardt minimization algorithm to find a least-squares best fit and a differential evolution Markov Chain Monte Carlo algorithm to find the best fit to the light curve. To constrain the red noise in both fitting models we used the residual permutation (rosary bead), time-averaging, and wavelet method.

Turner, Jake; Smart, B.; Pearson, K.; Biddle, L. I.; Cates, I.; Berube, M.; Thompson, R.; Smith, C.; Teske, J. K.; Hardegree-Ullman, K.; Robertson, A.; Crawfod, B.; Zellem, R.; Nieberding, M. N.; Raphael, B. A.; Tombleson, R.; Cook, K.; Hoglund, S.; Hofmann, R.; Jones, C.; Towner, A. P.; Small, L.; Walker-LaFollette, A.; Sanford, B.; Sagan, T.

2014-01-01

95

The Structural and Thermal Evolution of Transiting Exoplanets: From Hot Jupiters to Kepler's Super Earths  

Energy Technology Data Exchange (ETDEWEB)

Large numbers of exoplanets can now be seen to transit their parent stars, which allows for measurements of their radii, masses, and densities. We can now begin to examine the Jupiter-class gas giant planets as a class of astrophysical objects. At the same time, thanks to NASA’s Kepler telescope, the number of transiting planets below 10 Earth masses is now moving beyond just a handful. For the Jupiter-like planets, we model their interior structure and find several interesting properties regarding the amount of ice and rock within these planets, which gives us clues to their formation. For the lowest-mass planets, such as the 6-planet Kepler-11 system, signs point to a large populations of mini-Neptunes---low-mass, low-density planets with hydrogen-dominated atmospheres. The Kepler-11 system may tell us much about the evaporation of the atmospheres of these kinds of planets.

Fortney, Jonathan (University of California Santa Cruz)

2011-06-11

96

Accretion of Jupiter-mass Planets in the Limit of Vanishing Viscosity  

CERN Document Server

In the core-accretion model the nominal runaway gas-accretion phase brings most planets to multiple Jupiter masses. However, known giant planets are predominantly Jupiter-mass. Obtaining longer timescales for gas accretion may require using realistic equations of states, or accounting for the dynamics of the circumplanetary disk (CPD) in low-viscosity regime, or both. Here we explore the second way using global, three-dimensional isothermal hydrodynamical simulations with 8 levels of nested grids around the planet. In our simulations the vertical inflow from the circumstellar disk (CSD) to the CPD determines the shape of the CPD and its accretion rate. Even without prescribed viscosity Jupiter's mass-doubling time is $\\sim 10^4$ years, assuming the planet at 5.2 AU and a Minimum Mass Solar Nebula. However, we show that this high accretion rate is due to resolution-dependent numerical viscosity. Furthermore, we consider the scenario of a layered CSD, viscous only in its surface layer, and an inviscid CPD. We i...

Szulágyi, J; Crida, A; Masset, F

2013-01-01

97

TASTE: The Asiago Search for Transit timing variations of Exoplanets. I. Overview and improved parameters for HAT-P-3b and HAT-P-14b  

CERN Multimedia

A promising method to detect earth-sized exoplanets is the timing analysis of a known transit. The technique allows a search for variations in transit duration or center induced by the perturbation of a third body, e.g. a second planet or an exomoon. To this aim, TASTE (The Asiago Search for Transit timing variations of Exoplanets) project will collect high-precision, short-cadence light curves for a selected sample of transits by using imaging differential photometry at the Asiago 1.82m telescope. The first light curves show that our project can provide a competitive timing accuracy, as well as a significant improvement over the orbital parameters. We derived refined ephemerides for HAT-P-3b and HAT-P-14b thanks to a timing accuracy of 11 and 25 s, respectively.

Nascimbeni, V; Bedin, L R; Damasso, M

2010-01-01

98

Transiting exoplanets from the CoRoT space mission . XIII. CoRoT-13b: a dense hot Jupiter in transit around a star with solar metallicity and super-solar lithium content  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We announce the discovery of the transiting planet CoRoT-13b. Ground-based follow-up in CFHT and IAC80 confirmed CoRoT's observations. The mass of the planet was measured with the HARPS spectrograph and the properties of the host star were obtained analyzing HIRES spectra from the Keck telescope. It is a hot Jupiter-like planet with an orbital period of 4.04 days, 1.3 Jupiter masses, 0.9 Jupiter radii, and a density of 2.34 g cm[SUP]-3[/SUP]. It orbits a G0V star with T_eff = 5 945 K, M[SUB]*...

2010-01-01

99

A transit timing analysis of seven RISE light curves of the exoplanet system HAT-P-3  

CERN Multimedia

We present seven light curves of the exoplanet system HAT-P-3, taken as part of a transit timing program using the RISE instrument on the Liverpool Telescope. The light curves are analysed using a Markov-Chain Monte-Carlo algorithm to update the parameters of the system. The inclination is found to be i = 86.75^{+0.22}_{-0.21} deg, the planet-star radius ratio to be R_p/R_star = 0.1098^{+0.0010}_{-0.0012}, and the stellar radius to be R_star = 0.834^{+0.018}_{-0.026} R_sun, consistent with previous results but with a significant improvement in the precision. Central transit times and uncertainties for each light curve are also determined, and a residual permutation algorithm used as an independent check on the errors. The transit times are found to be consistent with a linear ephemeris, and a new ephemeris is calculated as T_c(0) = 2454856.70118 +- 0.00018 HJD and P = 2.899738 +- 0.000007 days. Model timing residuals are fitted to the measured timing residuals to place upper mass limits for a hypothetical per...

Gibson, N P; Barros, S; Benn, C; Christian, D; Hrudková, M; Joshi, Y C; Keenan, F P; Simpson, E K; Skillen, I; Steele, I A; Todd, I

2009-01-01

100

Discovery of 18 Jupiter mass RV companion orbiting the brown dwarf candidate ChaHa8  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report the discovery of a 16-20 Jupiter mass radial velocity companion around the very young (3 Myr) brown dwarf candidate ChaHa8. Based on high-resolution echelle spectra of ChaHa8 taken between 2000 and 2007 with UVES at the VLT, a companion was detected through RV variability with a semi-amplitude of 1.6 km/s. A Kepler fit to the data yields an orbital period of the companion of 1590 days and an eccentricity of e=0.49. A companion minimum mass M2sin i between 16 and 20...

Joergens, Viki; Mueller, Andre

2007-01-01

 
 
 
 
101

Confirmation of an exoplanet using the transit color signature: Kepler-418b, a blended giant planet in a multiplanet system  

CERN Document Server

We announce confirmation of Kepler-418b, one of two proposed planets in this system. This is the first confirmation of an exoplanet based primarily on the transit color signature technique. We used the Kepler public data archive combined with multicolor photometry from the Gran Telescopio de Canarias and radial velocity follow-up using FIES at the Nordic Optical Telescope for confirmation. We report a confident detection of a transit color signature that can only be explained by a compact occulting body, entirely ruling out a contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing binary. Those findings are corroborated by our radial velocity measurements, which put an upper limit of ~1 Mjup on the mass of Kepler-418b. We also report that the host star is significantly blended, confirming the ~10% light contamination suspected from the crowding metric in the Kepler light curve measured by the Kepler team. We report detection of an unresolved light source that contributes an additional ~4...

Tingley, B; Gandolfi, D; Deeg, H J; Pallé, E; Rodriguez, P Montañés; Murgas, F; Alonso, R; Bruntt, H; Fridlund, M

2014-01-01

102

Exoplanet properties from Lick, Keck and AAT  

Energy Technology Data Exchange (ETDEWEB)

Doppler-shift measurements with a remarkable precision of {delta}{lambda}/{lambda}=3x10{sup -9}, corresponding to velocities of 1 m s{sup -1}, have been made repeatedly of 2500 stars located within 300 light years. The observed gravitational perturbations of the stars have revealed 250 orbiting planets, with 27 that cross in front of the host star, blocking a fraction of the starlight to allow measurement of the planet's mass, radius and density. Two new discoveries are the first good analog of Jupiter (HD 154345b) and the first system of five planets (55 Cancri). The predominantly eccentric orbits of exoplanets probably result from planet-planet gravitational interactions or angular momentum exchange by mean-motion resonances. The planet mass distribution ranges from {approx}15 M{sub JUP} to as low as {approx}5 M{sub Earth} and rises toward lower masses as dN/dM{approx}M{sup -1.1}. The distribution with orbital distance, a, rises (in logarithmic intervals) as dN/d log a{approx}a{sup +0.4}. Extrapolation and integration suggests that 19% of all Sun-like stars harbor a gas-giant planet within 20 AU, but there remains considerable incompleteness for large orbits. Beyond 20 AU, the occurrence of gas-giant planets may be less than a few per cent as protoplanetary disk material there has lower densities and is vulnerable to destruction. Jupiter-mass planets occur more commonly around more massive stars than low mass stars. The transit of the Neptune-mass planet, Gliese 436b, yields a density of 1.55 g cm{sup -3} suggesting that its interior has an iron-silicate core surrounded by an envelope of water-ice and an outer H-He shell. Planets with masses as low as five Earth-masses may be commonly composed of iron-nickel, rock and water along with significant amounts of H and He, making the term 'super-Earth' misleading. The transiting planet HD147506b has high orbital eccentricity but no significant orbital inclination to the line of sight, presenting a puzzle about its history. Its orbit together with the mean motion resonances of 4 of the 22 multi-planet systems provides further evidence for the role of planet-planet interactions in shaping planetary architectures.

Marcy, G W; Wright, J T; Upadhyay, S [Department of Astronomy, MS3411, University of California, Berkeley, CA 94720 (United States); Butler, R P [Department of Terrestrial Magnetism, Carnegie Institute of Washington, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Vogt, S S [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Fischer, D A [Department of Physics and Astronomy, San Francisco State University, CA, 94132 (United States); Johnson, J A [Institute for Astronomy, Honolulu, HI 96822 (United States); Tinney, C G [Department of Astrophysics, University of New South Wales (Australia); Jones, H R A [Department of Astrophysics, University of Hertfordshire, Hatfield, AL10 9AB (United Kingdom); Carter, B D [Faculty of Sciences, University of Southern Queensland, Toowoomba, Queensland 4350 (Australia); Bailey, J [Australian Centre for Astrobiology, Macquarie University, Sydney, NSW 2109 (Australia); O' Toole, S J [Anglo-Australian Observatory, PO Box 296, Epping 1710 (Australia)], E-mail: gmarcy@berkeley.edu

2008-08-15

103

Discovery of 18 Jupiter mass RV companion orbiting the brown dwarf candidate ChaHa8  

CERN Multimedia

We report the discovery of a 16-20 Jupiter mass radial velocity companion around the very young (3 Myr) brown dwarf candidate ChaHa8. Based on high-resolution echelle spectra of ChaHa8 taken between 2000 and 2007 with UVES at the VLT, a companion was detected through RV variability with a semi-amplitude of 1.6 km/s. A Kepler fit to the data yields an orbital period of the companion of 1590 days and an eccentricity of e=0.49. A companion minimum mass M2sin i between 16 and 20 Jupiter masses is derived when using model-dependent mass estimates for the primary. The mass ratio M2/M1 might be as small as 0.2 and, with a probability of 87%, it is less than 0.4. ChaHa8 harbors most certainly the lowest mass companion detected so far in a close (~1 AU) orbit around a brown dwarf or very low-mass star. From the uncertainty in the orbit solution, it cannot completely be ruled out that the companion has a mass in the planetary regime. Its discovery is in any case an important step towards RV planet detections around BDs...

Joergens, Viki

2007-01-01

104

On the heat redistribution of the hot transiting exoplanet WASP-18b  

CERN Document Server

The energy deposition and redistribution in hot Jupiter atmospheres is not well understood currently, but is a major factor for their evolution and survival. We present a time dependent radiative transfer model for the atmosphere of WASP-18b which is a massive (10 MJup) hot Jupiter (Teq ~ 2400 K) exoplanet orbiting an F6V star with an orbital period of only 0.94 days. Our model includes a simplified parametrisation of the day-to-night energy redistribution by a modulation of the stellar heating mimicking a solid body rotation of the atmosphere. We present the cases with either no rotation at all with respect to the synchronously rotating reference frame or a fast differential rotation. The results of the model are compared to previous observations of secondary eclipses of Nymeyer et al. (2011) with the Spitzer Space Telescope. Their observed planetary flux suggests that the efficiency of heat distribution from the day-side to the night-side of the planet is extremely inefficient. Our results are consistent wi...

Iro, Nicolas

2013-01-01

105

The New Photometric Observations for Transiting Exoplanet HAT-P-24b  

Science.gov (United States)

The transiting exoplanetary system HAT-P-24 was observed by using CCD cameras at Yunnan Observatory and Hokoon Astronomical Centre, China in 2010 and 2012. Three new transit light curves are analyzed by means of MCMC technique, and the new physical parameters of the system are derived, which are compatible with the old ones in the discovery paper. The orbital period of HAT-P-24b is refined and no obvious TTV signal can be found from five transit events during 2010-2012.

Wang, Xiao-Bin; Cameron, Andrew Collier; Gu, Sheng-Hong

2014-04-01

106

The Effect of Conjunctions on the Transit Timing Variations of Exoplanets  

CERN Multimedia

We develop an analytic model for transit timing variations produced by orbital conjunctions between gravitationally interacting planets. If the planetary orbits have tight orbital spacing, which is a common case among the Kepler planets, the effect of a single conjunction can be best described as: (1) a step-like change of the transit timing ephemeris with subsequent transits of the inner planet being delayed and those of the outer planet being sped up, and (2) a discrete change in sampling of the underlying oscillations from eccentricity-related interaction terms. In the limit of small orbital eccentricities, our analytic model gives explicit equations for these effects as a function of the mass and orbital separation of planets. We point out that a detection of the conjunction effect in real data is of crucial importance for the physical characterization of planetary systems from transit timing variations.

Nesvorny, David

2014-01-01

107

NASA's Missions for Exoplanet Exploration  

Science.gov (United States)

Exoplanets are detected and characterized using a range of observational techniques - including direct imaging, astrometry, transits, microlensing, and radial velocities. Each technique illuminates a different aspect of exoplanet properties and statistics. This diversity of approach has contributed to the rapid growth of the field into a major research area in only two decades. In parallel with exoplanet observations, major efforts are now underway to interpret the physical and atmospheric properties of exoplanets for which spectroscopy is now possible. In addition, comparative planetology probes questions of interest to both exoplanets and solar system studies. In this talk I describe NASA's activities in exoplanet research, and discuss plans for near-future missions that have reflected-light spectroscopy as a key goal. The WFIRST-AFTA concept currently under active study includes a major microlensing survey, and now includes a visible light coronagraph for exoplanet spectroscopy and debris disk imaging. Two NASA-selected community-led teams are studying probe-scale (Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2014. California Institute of Technology. Government sponsorship acknowledged.

Unwin, Stephen

2014-05-01

108

Transit timing analysis of the exoplanets TrES-1 and TrES-2  

CERN Document Server

The aim of this work is a detailed analysis of transit light curves from TrES-1 and TrES-2, obtained over a period of three to four years, in order to search for variabilities in observed mid-transit times and to set limits for the presence of additional third bodies. Using the IAC 80cm telescope, we observed transits of TrES-1 and TrES-2 over several years. Based on these new data and previously published work, we studied the observed light curves and searched for variations in the difference between observed and calculated (based on a fixed ephemeris) transit times. To model possible transit timing variations, we used polynomials of different orders, simulated O-C diagrams corresponding to a perturbing third mass and sinusoidal fits. For each model we calculated the chi-squared residuals and the False Alarm Probability (FAP). For TrES-1 we can exclude planetary companions (>1 M_earth) in the 3:2 and 2:1 MMRs having high FAPs based on our transit observations from ground. Additionally, the presence of a ligh...

Rabus, M; Alonso, R; Belmonte, J A; Almenara, J M

2009-01-01

109

Search for Carbon Monoxide in the atmosphere of the Transiting Exoplanet HD189733b  

CERN Document Server

Water, methane and carbon-monoxide are expected to be among the most abundant molecules besides molecular hydrogen in the hot atmosphere of close-in EGPs. Transit observations in the mid-IR allow the atmospheric content of transiting planets to be determined. We present new primary transit observations of the hot-jupiter HD189733b, obtained simultaneously at 4.5 and 8 micron with IRAC instrument onboard Spitzer. Together with a new refined analysis of previous observations at 3.6 and 5.8 micron using the same instrument, we are able to derive the system parameters, including planet-to-star radius ratio, impact parameter, scale of the system, and central time of the transit from fits of the transit light curves at these four wavelengths. We measure the four planet-to-star radius ratios, to be (R_p/R_*)= 0.1545 +/- 0.0003, 0.1557 +/- 0.0003, 0.1547 +/- 0.0005, 0.1544 +/- 0.0004 at 3.6, 4.5, 5.8, and 8 micron respectively. The high accuracy of the measurement allows the search for atmospheric molecular absorbers...

Desert, Jean-Michel; Hebrard, Guillaume; Sing, David K; Ehrenreich, David; Ferlet, Roger; Vidal-Madjar, Alfred

2009-01-01

110

Exoplanet Transit Spectroscopy Using WFC3: WASP-12 b, WASP-17 b, and WASP-19 b  

CERN Document Server

We report analysis of transit spectroscopy of the extrasolar planets WASP-12 b, WASP-17 b, and WASP-19 b using the Wide Field Camera 3 on the HST. We analyze the data for a single transit for each planet using a strategy similar in certain aspects to the techniques used by Berta et al. (2012), but we extend their methodology to allow us to correct for channel- or wavelength-dependent instrumental effects by utilizing the band-integrated time series and measurements of the drift of the spectrum on the detector over time. We achieve almost photon-limited results for individual spectral bins, but the uncertainties in the transit depth for the the band-integrated data are exacerbated by the uneven sampling of the light curve imposed by the orbital phasing of HST's observations. Our final transit spectra for all three objects are consistent with the presence of a broad absorption feature at 1.4 microns potentially due to water. However, the amplitude of the absorption is less than that expected based on previous o...

Mandell, Avi; Sinukoff, Evan; Madhusudhan, Nikku; Burrows, Adam; Deming, Drake

2013-01-01

111

FIVE NEW TRANSIT EPOCHS OF THE EXOPLANET OGLE-TR-111b  

International Nuclear Information System (INIS)

We report five new transit epochs of the extrasolar planet OGLE-TR-111b, observed in the v-HIGH and Bessell I bands with the FORS1 and FORS2 at the ESO Very Large Telescope between 2008 April and May. The new transits have been combined with all previously published transit data for this planet to provide a new transit timing variations (TTVs) analysis of its orbit. We find no TTVs with amplitudes larger than 1.5 minutes over a four-year observation time baseline, in agreement with the recent result by Adams et al. Dynamical simulations fully exclude the presence of additional planets in the system with masses greater than 1.3, 0.4, and 0.5 M+ at the 3:2, 1:2, and 2:1 resonances, respectively. We also place an upper limit of about 30 M+ on the mass of potential second planets in the region between the 3:2 and 1:2 mean-motion resonances.

2011-05-20

112

Radial velocity follow-up of CoRoT transiting exoplanets  

Directory of Open Access Journals (Sweden)

Full Text Available We report on the results from the radial-velocity follow-up program performed to establish the planetary nature and to characterize the transiting candidates discovered by the space mission CoRoT. We use the SOPHIE at OHP, HARPS at ESO and the HIRES at Keck spectrographs to collect spectra and high-precision radial velocity (RV measurements for several dozens di?erent candidates from CoRoT. We have measured the Rossiter-McLaughlin e?ect of several con?rmed planets, especially CoRoT-1b which revealed that it is another highly inclined system. Such high-precision RV data are necessary for the discovery of new transiting planets. Furthermore, several low mass planet candidates have emerged from our Keck and HARPS data.

Deleuil M.

2011-02-01

113

Determination of parameters of transit exoplanets, using data obtained at the small telescopes  

Science.gov (United States)

We present the results of CCD-photometry data processing of some stars with transiting extrasolar planets. Observations were carried out using such small telescopes: a 38-cm Cassegrain telescope K-380 (CrAO, Ukraine), a 60-cm Zeiss-600 (Terskol, Russia), a Celestron-14? (Lesniki & MAO NASU, Ukraine). The main physical and orbital parameters for specified exoplanetary systems were calculated by the Monte-Carlo method. Using obtained best-fit parameters the light curve modeling was simulated. Calculations and light curve simulation were realized using an IDL programming environment. A light curve analysis includes simulation of a transit curve shape using the analytic theory of the light curve and experimentally obtained data. A comparison of the results obtained in each of the above mentioned telescopes is presented.

Krushevska, V.; Kuznyetsova, Yu.; Matsiaka, O.; Andreev, M.; Romanyuk, Ya.; Vidmachenko, A.

2014-03-01

114

New approach for modeling of transiting exoplanets for arbitrary limb-darkening law  

CERN Document Server

We present a new solution of the direct problem of planet transits based on transformation of double integrals to single ones. On the basis of our direct problem solution we created the code TAC-maker for rapid and interactive calculation of synthetic planet transits by numerical computations of the integrals. The validation of our approach was made by comparison with the results of the wide-spread Mandel & Agol (2002) method for the cases of linear, quadratic and squared root limb-darkening laws and various combinations of model parameters. For the first time our approach allows the use of arbitrary limb-darkening law of the host star. This advantage together with the practically arbitrary precision of the calculations make the code a valuable tool that faces the challenges of the continuously increasing photometric precision of the ground-based and space observations.

Kjurkchieva, D; Vladev, A; Yotov, V

2013-01-01

115

The Rossiter-McLaughlin Effect of the Transiting Exoplanet XO-4b  

CERN Document Server

We report photometric and radial velocity observations of the XO-4 transiting planetary system, conducted with the FLWO 1.2m telescope and the 8.2m Subaru Telescope. Based on the new light curves, the refined transit ephemeris of XO-4b is $P = 4.1250828 \\pm 0.0000040$ days and $T_c [BJD_TDB] = 2454485.93323 \\pm 0.00039$. We measured the Rossiter-McLaughlin effect of XO-4b and estimated the sky-projected angle between the stellar spin axis and the planetary orbital axis to be $\\lambda = -46.7^{\\circ} ^{+8.1^{\\circ}}_{-6.1^{\\circ}}$. This measurement of $\\lambda$ is less robust than in some other cases because the impact parameter of the transit is small, causing a strong degeneracy between $\\lambda$ and the projected stellar rotational velocity. Nevertheless, our finding of a spin-orbit misalignment suggests that the migration process for XO-4b involved few-body dynamics rather than interaction with a gaseous disk. In addition, our result conforms with the pattern reported by Winn et al. (2010, ApJL, 718, L145...

Narita, Norio; Sanchis-Ojeda, Roberto; Winn, Joshua N; Holman, Matthew J; Sato, Bun'ei; Aoki, Wako; Tamura, Motohide

2010-01-01

116

SEARCH FOR CARBON MONOXIDE IN THE ATMOSPHERE OF THE TRANSITING EXOPLANET HD 189733b  

International Nuclear Information System (INIS)

Water, methane, and carbon monoxide are expected to be among the most abundant molecules besides molecular hydrogen in the hot atmosphere of close-in extrasolar giant planets. Atmospheric models for these planets predict that the strongest spectrophotometric features of those molecules are located at wavelengths ranging from 1 to 10 ?m making this region of particular interest. Consequently, transit observations in the mid-infrared (mid-IR) allow the atmospheric content of transiting planets to be determined. We present new primary transit observations of the hot-Jupiter HD 189733b, obtained simultaneously at 4.5 and 8 ?m with the Infrared Array Camera onboard the Spitzer Space Telescope. Together with a new refined analysis of previous observations at 3.6 and 5.8 ?m using the same instrument, we are able to derive the system parameters, including planet-to-star radius ratio, impact parameter, scale of the system, and central time of the transit from fits of the transit light curves at these four wavelengths. We measure the four planet-to-star radius ratios, to be (Rp /R *)3.6?m = 0.1545 ± 0.0003, (Rp /R*)4.5?m = 0.1557 ± 0.0003, (Rp /R *)5.8?m = 0.1547 ± 0.0005, and (Rp/R*)8?m = 0.1544 ± 0.0004. The high accuracy of the planet radii measurement allows the search for atmospheric molecular absorbers. Contrary to a previous analysis of the same data set, our study is robust against systematics and reveals that water vapor absorption at 5.8 ?m is not detected in this photometric data set. Furthermore, in the band centered around 4.5 ?m we find a hint of excess absorption with an apparent planetary radius ?Rp /R * = 0.00128 ± 0.00056 larger (2.3?) than the one measured simultaneously at 8 ?m. This value is 4? above what would be expected for an atmosphere where water vapor is the only absorbing species in the near-IR. This shows that an additional species absorbing around 4.5 ?m could be present in the atmosphere. Carbon monoxide (CO) being a strong absorber at this wavelength is a possible candidate and this may suggest a large CO/H2O ratio between 5 and 60.

2009-07-01

117

The Qatar Exoplanet Survey  

Science.gov (United States)

The Qatar Exoplanet Survey (QES) is discovering hot Jupiters and aims to discover hot Saturns and hot Neptunes that transit in front of relatively bright host stars. QES currently operates a robotic wide-angle camera system to identify promising transiting exoplanet candidates among which are the confirmed exoplanets Qatar 1b and 2b. This paper describes the first generation QES instrument, observing strategy, data reduction techniques, and follow-up procedures. The QES cameras in New Mexico complement the SuperWASP cameras in the Canary Islands and South Africa, and we have developed tools to enable the QES images and light curves to be archived and analysed using the same methods developed for the SuperWASP datasets. With its larger aperture, finer pixel scale, and comparable field of view, and with plans to deploy similar systems at two further sites, the QES, in collaboration with SuperWASP, should help to speed the discovery of smaller radius planets transiting bright stars in northern skies.

Alsubai, K. A.; Parley, N. R.; Bramich, D. M.; Horne, K.; Collier Cameron, A.; West, R. G.; Sorensen, P. M.; Pollacco, D.; Smith, J. C.; Fors, O.

2013-12-01

118

The Qatar Exoplanet Survey  

CERN Document Server

The Qatar Exoplanet Survey (QES) is discovering hot Jupiters and aims to discover hot Saturns and hot Neptunes that transit in front of relatively bright host stars. QES currently operates a robotic wide-angle camera system to identify promising transiting exoplanet candidates among which are the confirmed exoplanets Qatar 1b and 2b. This paper describes the first generation QES instrument, observing strategy, data reduction techniques, and follow-up procedures. The QES cameras in New Mexico complement the SuperWASP cameras in the Canary Islands and South Africa, and we have developed tools to enable the QES images and light curves to be archived and analysed using the same methods developed for the SuperWASP datasets. With its larger aperture, finer pixel scale, and comparable field of view, and with plans to deploy similar systems at two further sites, the QES, in collaboration with SuperWASP, should help to speed the discovery of smaller radius planets transiting bright stars in northern skies.

Alsubai, K A; Bramich, D M; Horne, K; Cameron, A Collier; West, R G; Sorensen, P M; Pollacco, D; Smith, J C; Fors, O

2014-01-01

119

Transiting exoplanets from the CoRoT space mission Resolving the nature of transit candidates for the LRa03 and SRa03 fields  

Science.gov (United States)

CoRoT is a space telescope which aims at studying internal structure of stars and detecting extrasolar planets. We present here a list of transits detected in the light curves of stars observed by CoRoT in two fields in the anti-center direction: the LRa03 one observed during 148 days from 3 October 2009 to 1 March 2010 followed by the SRa03 one from the 5 March 2010 to the 29 March 2010 during 25 days. 5329 light curves for the LRa03 field and 4169 for the SRa03 field were analyzed by the detection team of CoRoT. Then some of the selected exoplanetary candidates have been followed up from the ground. In the LRa03 field, 19 exoplanet candidates have been found, 8 remain unsolved. No secured planet has been found yet. In the SRa03 field, there were 11 exoplanetary candidates among which 6 cases remain unsolved and 3 planets have been found: CoRoT-18b, CoRoT-19b, CoRoT-20b.

Cavarroc, C.; Moutou, C.; Gandolfi, D.; Tingley, B.; Ollivier, M.; Aigrain, S.; Alonso, R.; Almenara, J.-M.; Auvergne, M.; Baglin, A.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Cabrera, J.; Carpano, S.; Carone, L.; Cochran, W. D.; Csizmadia, S.; Deeg, H. J.; Deleuil, M.; Díaz, R. F.; Dvorak, R.; Endl, M.; Erikson, A.; Fridlund, M.; Gillon, M.; Guenther, E. W.; Guillot, T.; Hatzes, A.; Hébrard, G.; Jorda, L.; Léger, A.; Lammer, H.; Lev, T.-O.; Lovis, C.; MacQueen, P. J.; Mazeh, T.; Ofir, A.; Parviainen, H.; Pasternacki, T.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Samuel, B.; Santerne, A.; Schneider, J.; Weingrill, J.; Wuchterl, G.

2012-02-01

120

Transiting exoplanets from the CoRoT space mission Resolving the nature of transit candidates for the LRa03 and SRa03 fields  

DEFF Research Database (Denmark)

CoRoT is a space telescope which aims at studying internal structure of stars and detecting extrasolar planets. We present here a list of transits detected in the light curves of stars observed by CoRoT in two fields in the anti-center direction: the LRa03 one observed during 148 days from 3 October 2009 to 1 March 2010 followed by the SRa03 one from the 5 March 2010 to the 29 March 2010 during 25 days. 5329 light curves for the LRa03 field and 4169 for the SRa03 field were analyzed by the detection team of CoRoT. Then some of the selected exoplanetary candidates have been followed up from the ground. In the LRa03 field, 19 exoplanet candidates have been found, 8 remain unsolved. No secured planet has been found yet. In the SRa03 field, there were 11 exoplanetary candidates among which 6 cases remain unsolved and 3 planets have been found: CoRoT-18b, CoRoT-19b, CoRoT-20b. Astrophysics and Space Science Astrophysics and Space Science Look Inside Other actions Export citations Register for Journal Updates About This Journal Reprints and Permissions

Cavarroc, C.; Moutou, C.

2012-01-01

 
 
 
 
121

The Effects of Refraction on Transit Transmission Spectroscopy: Application to Earth-like Exoplanets  

CERN Document Server

We quantify the effects of refraction in transit transmission spectroscopy on spectral absorption features and on temporal variations that could be used to obtain altitude-dependent spectra for planets orbiting stars of different stellar types. We validate our model against altitude-dependent transmission spectra of the Earth from ATMOS and against lunar eclipse spectra from Palle et al. (2009). We perform detectability studies to show the potential effects of refraction on hypothetical observations of Earth analogs with the James Webb Space Telescope (JWST) Near-Infrared Spectrograph (NIRSPEC). Due to refraction, there will be a maximum tangent pressure level that can be probed during transit for each given planet-star system. We show that because of refraction, for an Earth-analog planet orbiting in the habitable zone of a Sun-like star only the top 0.3 bars of the atmosphere can be probed, leading to a decrease in the signal to noise ratio (SNR) of absorption features by 60%, while for an Earth-analog plan...

Misra, Amit; Crisp, Dave

2014-01-01

122

Improved Modeling of the Rossiter-McLaughlin Effect for Transiting Exoplanets  

CERN Document Server

We present an improved formula for the anomalous radial velocity of the star during planetary transits due to the Rossiter-McLaughlin (RM) effect. The improvement comes from a more realistic description of the stellar absorption line profiles, taking into account stellar rotation, macroturbulence, thermal broadening, pressure broadening, and instrumental broadening. Although the formula is derived for the case in which radial velocities are measured by cross-correlation, we show through numerical simulations that the formula accurately describes the cases where the radial velocities are measured with the iodine absorption-cell technique. The formula relies on prior knowledge of the parameters describing macroturbulence, instrumental broadening and other broadening mechanisms, but even 30% errors in those parameters do not significantly change the results in typical circumstances. We show that the new analytic formula agrees with previous ones that had been computed on a case-by-case basis via numerical simula...

Hirano, Teruyuki; Winn, Joshua N; Taruya, Atsushi; Narita, Norio; Albrecht, Simon; Sato, Bun'ei

2011-01-01

123

INDEPENDENT DISCOVERY OF THE TRANSITING EXOPLANET HAT-P-14b  

International Nuclear Information System (INIS)

We present SuperWASP observations of HAT-P-14b, a hot Jupiter discovered by Torres et al. The planet was found independently by the SuperWASP team and named WASP-27b after follow-up observations had secured the discovery, but prior to the publication by Torres et al. Our analysis of HAT-P-14/WASP-27 is in good agreement with the values found by Torres et al. and we provide additional evidence against astronomical false positives. Due to the brightness of the host star, Vmag = 10, HAT-P-14b is an attractive candidate for further characterization observations. The planet has a high impact parameter and the primary transit is close to grazing. This could readily reveal small deviations in the orbital parameters indicating the presence of a third body in the system, which may be causing the small but significant orbital eccentricity. Our results suggest that the planet may undergo a grazing secondary eclipse. However, even a non-detection would tightly constrain the system parameters.

2011-05-01

124

Independent discovery and refined parameters of the transiting exoplanet HAT-P-14b  

CERN Document Server

We present SuperWASP observations of HAT-P-14b, a hot Jupiter discovered by Torres et al. The planet was found independently by the SuperWASP team and named WASP-27b after follow-up observations had secured the discovery, but prior to the publication by Torres et al. Our analysis of HAT-P-14/WASP-27 is in good agreement with the values found by Torres et al. and we refine the parameters by combining our datasets. We also provide additional evidence against astronomical false positives. Due to the brightness of the host star, V = 10, HAT-P-14 is an attractive candidate for further characterisation observations. The planet has a high impact parameter, b = 0.907 +/- 0.004, and the primary transit is close to grazing. This could readily reveal small deviations in the orbital parameters indicating the presence of a third body in the system, which may be causing the small but significant orbital eccentricity, e = 0.095 +/- 0.011. The system geometry suggests that the planet narrowly fails to undergo a secondary ecl...

Simpson, E K; Brown, D J A; Cameron, A Collier; Pollacco, D; Skillen, I; Stempels, H C; Boisse, I; Faedi, F; Hebrard, G; McCormac, J; Sorensen, P; Street, R A; Bento, J; Bouchy, F; Butters, O W; Enoch, B; Haswell, C A; Hebb, L; Holmes, S; Horne, K; Keenan, F P; Lister, T A; Miller, G R M; Moulds, V; Moutou, C; Norton, A J; Parley, N; Santerne, A; Todd, I; Watson, C A; West, R G; Wheatley, P J

2010-01-01

125

CONSTRAINING HIGH-SPEED WINDS IN EXOPLANET ATMOSPHERES THROUGH OBSERVATIONS OF ANOMALOUS DOPPLER SHIFTS DURING TRANSIT  

Energy Technology Data Exchange (ETDEWEB)

Three-dimensional (3D) dynamical models of hot Jupiter atmospheres predict very strong wind speeds. For tidally locked hot Jupiters, winds at high altitude in the planet's atmosphere advect heat from the day side to the cooler night side of the planet. Net wind speeds on the order of 1-10 km s{sup -1} directed towards the night side of the planet are predicted at mbar pressures, which is the approximate pressure level probed by transmission spectroscopy. These winds should result in an observed blueshift of spectral lines in transmission on the order of the wind speed. Indeed, Snellen et al. recently observed a 2 {+-} 1 km s{sup -1} blueshift of CO transmission features for HD 209458b, which has been interpreted as a detection of the day-to-night (substellar to anti-stellar) winds that have been predicted by 3D atmospheric dynamics modeling. Here, we present the results of a coupled 3D atmospheric dynamics and transmission spectrum model, which predicts the Doppler-shifted spectrum of a hot Jupiter during transit resulting from winds in the planet's atmosphere. We explore four different models for the hot Jupiter atmosphere using different prescriptions for atmospheric drag via interaction with planetary magnetic fields. We find that models with no magnetic drag produce net Doppler blueshifts in the transmission spectrum of {approx}2 km s{sup -1} and that lower Doppler shifts of {approx}1 km s{sup -1} are found for the higher drag cases, results consistent with-but not yet strongly constrained by-the Snellen et al. measurement. We additionally explore the possibility of recovering the average terminator wind speed as a function of altitude by measuring Doppler shifts of individual spectral lines and spatially resolving wind speeds across the leading and trailing terminators during ingress and egress.

Miller-Ricci Kempton, Eliza [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Rauscher, Emily, E-mail: ekempton@ucolick.org [Lunar and Planetary Laboratory, University of Arizona, 1629 East University Boulevard, Tucson, AZ 85721 (United States)

2012-06-01

126

CONSTRAINING HIGH-SPEED WINDS IN EXOPLANET ATMOSPHERES THROUGH OBSERVATIONS OF ANOMALOUS DOPPLER SHIFTS DURING TRANSIT  

International Nuclear Information System (INIS)

Three-dimensional (3D) dynamical models of hot Jupiter atmospheres predict very strong wind speeds. For tidally locked hot Jupiters, winds at high altitude in the planet's atmosphere advect heat from the day side to the cooler night side of the planet. Net wind speeds on the order of 1-10 km s–1 directed towards the night side of the planet are predicted at mbar pressures, which is the approximate pressure level probed by transmission spectroscopy. These winds should result in an observed blueshift of spectral lines in transmission on the order of the wind speed. Indeed, Snellen et al. recently observed a 2 ± 1 km s–1 blueshift of CO transmission features for HD 209458b, which has been interpreted as a detection of the day-to-night (substellar to anti-stellar) winds that have been predicted by 3D atmospheric dynamics modeling. Here, we present the results of a coupled 3D atmospheric dynamics and transmission spectrum model, which predicts the Doppler-shifted spectrum of a hot Jupiter during transit resulting from winds in the planet's atmosphere. We explore four different models for the hot Jupiter atmosphere using different prescriptions for atmospheric drag via interaction with planetary magnetic fields. We find that models with no magnetic drag produce net Doppler blueshifts in the transmission spectrum of ?2 km s–1 and that lower Doppler shifts of ?1 km s–1 are found for the higher drag cases, results consistent with—but not yet strongly constrained by—the Snellen et al. measurement. We additionally explore the possibility of recovering the average terminator wind speed as a function of altitude by measuring Doppler shifts of individual spectral lines and spatially resolving wind speeds across the leading and trailing terminators during ingress and egress.

2012-06-01

127

TRANSIT AND ECLIPSE ANALYSES OF THE EXOPLANET HD 149026b USING BLISS MAPPING  

International Nuclear Information System (INIS)

The dayside of HD 149026b is near the edge of detectability by the Spitzer Space Telescope. We report on 11 secondary-eclipse events at 3.6, 4.5, 3 × 5.8, 4 × 8.0, and 2 × 16 ?m plus three primary-transit events at 8.0 ?m. The eclipse depths from jointly fit models at each wavelength are 0.040% ± 0.003% at 3.6 ?m, 0.034% ± 0.006% at 4.5 ?m, 0.044% ± 0.010% at 5.8 ?m, 0.052% ± 0.006% at 8.0 ?m, and 0.085% ± 0.032% at 16 ?m. Multiple observations at the longer wavelengths improved eclipse-depth signal-to-noise ratios by up to a factor of two and improved estimates of the planet-to-star radius ratio (Rp /R* = 0.0518 ± 0.0006). We also identify no significant deviations from a circular orbit and, using this model, report an improved period of 2.8758916 ± 0.0000014 days. Chemical-equilibrium models find no indication of a temperature inversion in the dayside atmosphere of HD 149026b. Our best-fit model favors large amounts of CO and CO2, moderate heat redistribution (f = 0.5), and a strongly enhanced metallicity. These analyses use BiLinearly-Interpolated Subpixel Sensitivity (BLISS) mapping, a new technique to model two position-dependent systematics (intrapixel variability and pixelation) by mapping the pixel surface at high resolution. BLISS mapping outperforms previous methods in both speed and goodness of fit. We also present an orthogonalization technique for linearly correlated parameters that accelerates the convergence of Markov chains that employ the Metropolis random walk sampler. The electronic supplement contains light-curve files.

2012-08-01

128

TRANSIT AND ECLIPSE ANALYSES OF THE EXOPLANET HD 149026b USING BLISS MAPPING  

Energy Technology Data Exchange (ETDEWEB)

The dayside of HD 149026b is near the edge of detectability by the Spitzer Space Telescope. We report on 11 secondary-eclipse events at 3.6, 4.5, 3 Multiplication-Sign 5.8, 4 Multiplication-Sign 8.0, and 2 Multiplication-Sign 16 {mu}m plus three primary-transit events at 8.0 {mu}m. The eclipse depths from jointly fit models at each wavelength are 0.040% {+-} 0.003% at 3.6 {mu}m, 0.034% {+-} 0.006% at 4.5 {mu}m, 0.044% {+-} 0.010% at 5.8 {mu}m, 0.052% {+-} 0.006% at 8.0 {mu}m, and 0.085% {+-} 0.032% at 16 {mu}m. Multiple observations at the longer wavelengths improved eclipse-depth signal-to-noise ratios by up to a factor of two and improved estimates of the planet-to-star radius ratio (R{sub p} /R{sub *} = 0.0518 {+-} 0.0006). We also identify no significant deviations from a circular orbit and, using this model, report an improved period of 2.8758916 {+-} 0.0000014 days. Chemical-equilibrium models find no indication of a temperature inversion in the dayside atmosphere of HD 149026b. Our best-fit model favors large amounts of CO and CO{sub 2}, moderate heat redistribution (f = 0.5), and a strongly enhanced metallicity. These analyses use BiLinearly-Interpolated Subpixel Sensitivity (BLISS) mapping, a new technique to model two position-dependent systematics (intrapixel variability and pixelation) by mapping the pixel surface at high resolution. BLISS mapping outperforms previous methods in both speed and goodness of fit. We also present an orthogonalization technique for linearly correlated parameters that accelerates the convergence of Markov chains that employ the Metropolis random walk sampler. The electronic supplement contains light-curve files.

Stevenson, Kevin B.; Harrington, Joseph; Hardy, Ryan A.; Nymeyer, Sarah; Bowman, William C.; Cubillos, Patricio; Bowman, M. Oliver; Hardin, Matthew [Planetary Sciences Group, Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, CA 95064 (United States); Loredo, Thomas J., E-mail: kevin218@knights.ucf.edu [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853-6801 (United States)

2012-08-01

129

TraMoS project III: Improved physical parameters, timing analysis, and star-spot modelling of the WASP-4b exoplanet system from 38 transit observations  

CERN Multimedia

We report twelve new transit observations of the exoplanet WASP-4b from the Transit Monitoring in the South Project (TraMoS) project. These transits are combined with all previously published transit data for this planet to provide an improved radius measurement of Rp = 1.395 +- 0.022 Rjup and improved transit ephemerides. In a new homogeneous analysis in search for Transit Timing Variations (TTVs) we find no evidence of those with RMS amplitudes larger than 20 seconds over a 4-year time span. This lack of TTVs rules out the presence of additional planets in the system with masses larger than about 2.5 M_earth, 2.0 M_earth, and 1.0 M_earth around the 1:2, 5:3 and 2:1 orbital resonances. Our search for the variation of other parameters, such as orbital inclination and transit depth also yields negative results over the total time span of the transit observations. Finally we perform a simple study of stellar spots configurations of the system and conclude that the star rotational period is about 34 days.

Hoyer, S; Rojo, P; Nascimbeni, V; Hidalgo, S; Astudillo-Defru, N; Concha, F; Contreras, Y; Servajean, E; Hinse, T C

2013-01-01

130

THE TRANSIT LIGHT-CURVE PROJECT. XIV. CONFIRMATION OF ANOMALOUS RADII FOR THE EXOPLANETS TrES-4b, HAT-P-3b, AND WASP-12b  

International Nuclear Information System (INIS)

We present transit photometry of three exoplanets, TrES-4b, HAT-P-3b, and WASP-12b, allowing for refined estimates of the systems' parameters. TrES-4b and WASP-12b were confirmed to be 'bloated' planets, with radii of 1.706 ± 0.056RJup and 1.736 ± 0.092RJup, respectively. These planets are too large to be explained with standard models of gas giant planets. In contrast, HAT-P-3b has a radius of 0.827 ± 0.055RJup, smaller than a pure hydrogen-helium planet and indicative of a highly metal-enriched composition. Analyses of the transit timings revealed no significant departures from strict periodicity. For TrES-4, our relatively recent observations allow for improvement in the orbital ephemerides, which is useful for planning future observations.

2011-06-01

131

The NASA Exoplanet Archive: Data and Tools for Exoplanet Research  

CERN Document Server

We describe the contents and functionality of the NASA Exoplanet Archive, a database and tool set funded by NASA to support astronomers in the exoplanet community. The current content of the database includes interactive tables containing properties of all published exoplanets, Kepler planet candidates, threshold-crossing events, data validation reports and target stellar parameters, light curves from the Kepler and CoRoT missions and from several ground-based surveys, and spectra and radial velocity measurements from the literature. Tools provided to work with these data include a transit ephemeris predictor, both for single planets and for observing locations, light curve viewing and normalization utilities, and a periodogram and phased light curve service. The archive can be accessed at http://exoplanetarchive.ipac.caltech.edu.

Akeson, R L; Ciardi, D; Crane, M; Good, J; Harbut, M; Jackson, E; Kane, S R; Laity, A C; Leifer, S; Lynn, M; McElroy, D L; Papin, M; Plavchan, P; Ramirez, S V; Rey, R; von Braun, K; Wittman, M; Abajian, M; Ali, B; Beichman, C; Beekley, A; Berriman, G B; Berukoff, S; Bryden, G; Chan, B; Groom, S; Lau, C; Payne, A N; Regelson, M; Saucedo, M; Schmitz, M; Stauffer, J; Wyatt, P; Zhang, A

2013-01-01

132

On the (im)possibility of testing new physics in exoplanets using transit timing variations: deviation from inverse-square law of gravity  

Science.gov (United States)

Ground-based and space-borne observatories studying exoplanetary transits now and in the future will considerably increase the number of known exoplanets and the precision of the measured times of transit minima. Variations in the transit times can not only be used to infer the presence of additional planets, but might also provide opportunities for testing new physics in the places beyond the Solar system. In this work, we take deviation from the inverse-square law of gravity as an example, focus on the fifth-force-like Yukawa-type correction to the Newtonian gravitational force which parameterizes this deviation, investigate its effects on the secular transit timing variations and analyse their observability in exoplanetary systems. It is found that the most optimistic values of Yukawa-type secular transit timing variations are at the level of ˜0.1 s per year. Those values unfortunately appear only in rarely unique cases and, most importantly, they are still at least two orders of magnitude below the current capabilities of observations. Such a deviation from the inverse-square law of gravity is likely too small to detect for the foreseeable future. Meanwhile, systematic uncertainties, such as the presence of additional and unknown planets, will likely be exceptionally difficult to remove from a signal that should be seen.

Xie, Yi; Deng, Xue-Mei

2014-02-01

133

On the (im)possibility of testing new physics in exoplanets using transit timing variations: deviation from inverse-square law of gravity  

CERN Document Server

Ground-based and space-borne observatories studying exoplanetary transits now and in the future will considerably increase the number of known exoplanets and the precision of the measured times of transit minima. Variations in the transit times can not only be used to infer the presence of additional planets, but might also provide opportunities for testing new physics in the places beyond the Solar system. In this work, we take deviation from the inverse-square law of gravity as an example, focus on the fifth-force-like Yukawa-type correction to the Newtonian gravitational force which parameterizes this deviation, investigate its effects on the secular transit timing variations and analyze their observability in exoplanetary systems. It is found that the most optimistic values of Yukawa-type secular transit timing variations are at the level of $\\sim 0.1$ seconds per year. Those values unfortunately appear only in rarely unique cases and, most importantly, they are still at least two orders of magnitude belo...

Xie, Yi

2014-01-01

134

The Fabra-ROA Baker-Nunn Camera at Observatori Astronòmic del Montsec: A Wide-field Imaging Facility for Exoplanet Transit Detection  

Science.gov (United States)

A number of Baker-Nunn Camera (BNC) were manufactured by Smithsonian Institution during the 60’s as optical tracking systems for artificial satellites with optimal optical and mechanical specifications. One of them was installed at the Real Instituto y Observatorio de la Armada (ROA). We have conducted a profound refurbishment project of the telescope to be installed at Observatori Astronòmic del Montsec (OAdM) (Fors 2009). As a result, the BNC offers the largest combination of a huge FOV (4.4°×4.4°) and aperture (leading to a limiting magnitude of V˜20). These specifications, together with their remote and robotic natures, allows this instrument to face an observational program of exoplanets detection by means of transit technique with high signal-to-noise ratio in the appropiate magnitude range.

Fors, O.; Núñez, J.; Muiños, J. L.; Montojo, F. J.; Baena, R.; Merino, M.; Morcillo, R.; Blanco, V.

2010-10-01

135

Observation of the full 12-hour-long transit of the exoplanet HD80606b. Warm-Spitzer photometry and SOPHIE spectroscopy  

CERN Multimedia

We present new observations of a transit of the 111-day-period exoplanet HD80606b. Using the Spitzer Space Telescope and its IRAC camera on the post-cryogenic mission, we performed a 19-hour-long photometric observation of HD80606 that covers the full transit of 13-14 January 2010. We complement this photometric data by new spectroscopic observations that we simultaneously performed with SOPHIE at Haute-Provence Observatory. This provides radial velocity measurements of the first half of the transit that was previously uncovered with spectroscopy. This new data set allows the parameters of this singular planetary system to be significantly refined. We obtained a planet-to-star radius ratio R_p/R_* = 0.1001 +/- 0.0006 that is slightly lower than the one measured from previous ground observations. We detected a feature in the Spitzer light curve that could be due to a stellar spot. We also found a transit timing about 20 minutes earlier than the ephemeris prediction; this could be caused by actual TTVs due to a...

Hebrard, G; Diaz, R F; Boisse, I; Bouchy, F; Etangs, A Lecavelier des; Moutou, C; Ehrenreich, D; Arnold, L; Bonfils, X; Delfosse, X; Desort, M; Eggenberger, A; Forveille, T; Gregorio, J; Lagrange, A -M; Lovis, C; Pepe, F; Perrier, C; Pont, F; Queloz, D; Santerne, A; Santos, N C; Segransan, D; Sing, D K; Udry, S; Vidal-Madjar, A

2010-01-01

136

Transiting exoplanets from the CoRoT space mission XIV. CoRoT-11b: a transiting massive "hot-Jupiter" in a prograde orbit around a rapidly rotating F-type star  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The CoRoT exoplanet science team announces the discovery of CoRoT-11b, a fairly massive hot-Jupiter transiting a V=12.9 mag F6 dwarf star (M*=1.27 +/- 0.05 Msun, R*=1.37 +/- 0.03 Rsun, Teff=6440 +/- 120 K), with an orbital period of P=2.994329 +/- 0.000011 days and semi-major axis a=0.0436 +/- 0.005 AU. The detection of part of the radial velocity anomaly caused by the Rossiter-McLaughlin effect shows that the transit-like events detected by CoRoT are caused by a planet-sized transiting objec...

2010-01-01

137

Deserts and pile-ups in the distribution of exoplanets due to photoevaporative disc clearing  

CERN Document Server

We present models of giant planet migration in evolving protoplanetary discs. We show that disc clearing by EUV photoevaporation can have a strong effect on the distribution of giant planet semi-major axes. During disc clearing planet migration is slowed or accelerated in the region where photoevaporation opens a gap in the disc, resulting in "deserts" where few giant planets are found and corresponding "pile-ups" at smaller and larger radii. However, the precise locations and sizes of these features are strong functions of the efficiency of planetary accretion, and therefore also strongly dependent on planet mass. We suggest that photoevaporative disc clearing may be responsible for the pile-up of ~Jupiter-mass planets at ~1AU seen in exoplanet surveys, and show that observations of the distribution of exoplanet semi-major axes can be used to test models of both planet migration and disc clearing.

Alexander, R D

2012-01-01

138

Exoplanet Surveys at Universidad de Chile  

Science.gov (United States)

We present and highlight the first results of the three main exoplanet surveys we are currently conducting at Universidad de Chile: CHEPS, Red Giant Exoplanets (radial velocity), and TraMoS (transit lightcurves). We have several interesting candidates at the Calan-Hertfordshire Extrasolar Planet Search (CHEPS) project, which is aimed at searching for the currently missing southern bright transiting planets at a few m/s radial velocity precision. Using the same technique, we are also characterizing the planetary population in a constrained sample of Red Giant stars. The Transit Monitoring from the South (TraMoS) project is aimed both at improving transit parameters and at detecting any kind of lightcurve variability from several known southern exoplanet systems.

Rojo, Patricio; Jenkins, James; Hoyer, Sergio; Jones, Matías

2014-04-01

139

Transiting exoplanets from the CoRoT space mission . XIII. CoRoT-13b: a dense hot Jupiter in transit around a star with solar metallicity and super-solar lithium content  

Science.gov (United States)

We announce the discovery of the transiting planet CoRoT-13b. Ground-based follow-up in CFHT and IAC80 confirmed CoRoT's observations. The mass of the planet was measured with the HARPS spectrograph and the properties of the host star were obtained analyzing HIRES spectra from the Keck telescope. It is a hot Jupiter-like planet with an orbital period of 4.04 days, 1.3 Jupiter masses, 0.9 Jupiter radii, and a density of 2.34 g cm-3. It orbits a G0V star with T_eff = 5 945 K, M* = 1.09 M?, R_* = 1.01 R?, solar metallicity, a lithium content of + 1.45 dex, and an estimated age of between 0.12 and 3.15 Gyr. The lithium abundance of the star is consistent with its effective temperature, activity level, and age range derived from the stellar analysis. The density of the planet is extreme for its mass, implies that heavy elements are present with a mass of between about 140 and 300 {M}?. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain. Part of the observations were obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. Based on observations made with HARPS spectrograph on the 3.6-m European Organisation for Astronomical Research in the Southern Hemisphere telescope at La Silla Observatory, Chile (ESO program 184.C-0639). Based on observations made with the IAC80 telescope operated on the island of Tenerife by the Instituto de Astrofísica de Canarias in the Spanish Observatorio del Teide. Part of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Cabrera, J.; Bruntt, H.; Ollivier, M.; Díaz, R. F.; Csizmadia, Sz.; Aigrain, S.; Alonso, R.; Almenara, J.-M.; Auvergne, M.; Baglin, A.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Carone, L.; Carpano, S.; Deleuil, M.; Deeg, H. J.; Dvorak, R.; Erikson, A.; Ferraz-Mello, S.; Fridlund, M.; Gandolfi, D.; Gazzano, J.-C.; Gillon, M.; Guenther, E. W.; Guillot, T.; Hatzes, A.; Havel, M.; Hébrard, G.; Jorda, L.; Léger, A.; Llebaria, A.; Lammer, H.; Lovis, C.; Mazeh, T.; Moutou, C.; Ofir, A.; von Paris, P.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Santerne, A.; Schneider, J.; Tingley, B.; Titz-Weider, R.; Wuchterl, G.

2010-11-01

140

Project PANOPTES: Crowdsourcing the Search for Exoplanets  

Science.gov (United States)

Since the first exoplanets were discovered twenty years ago, nearly 1,000 have been confirmed. Over a third of these were found with the transit method, which holds the promise of more wide-scale searches. If Earth is in their orbital plane, exoplanets will partially eclipse their parent star. The transit method looks for this dimming to measure the size and orbit of the planet. Project PANOPTES is a crowdsourced search for new exoplanets using hobbyist digital cameras, keeping the cost low to make the search broadly accessible. We present information from our attempts to use a Canon EOS Rebel T4i DSLR camera with a Rokinon 85mm aspherical lens to detect transits, and we evaluate the feasibility of building a PANOPTES observatory in Southern Ohio.

Stump, Chad

2014-01-01

 
 
 
 
141

A transit timing analysis of nine RISE light curves of the exoplanet system TrES-3  

CERN Multimedia

We present nine newly observed transits of TrES-3, taken as part of a transit timing program using the RISE instrument on the Liverpool Telescope. A Markov-Chain Monte-Carlo analysis was used to determine the planet-star radius ratio and inclination of the system, which were found to be Rp/Rstar=0.1664^{+0.0011}_{-0.0018} and i = 81.73^{+0.13}_{-0.04} respectively, consistent with previous results. The central transit times and uncertainties were also calculated, using a residual-permutation algorithm as an independent check on the errors. A re-analysis of eight previously published TrES-3 light curves was conducted to determine the transit times and uncertainties using consistent techniques. Whilst the transit times were not found to be in agreement with a linear ephemeris, giving chi^2 = 35.07 for 15 degrees of freedom, we interpret this to be the result of systematics in the light curves rather than a real transit timing variation. This is because the light curves that show the largest deviation from a con...

Gibson, N P; Skillen, I; Simpson, E K; Barros, S; Joshi, Y C; Todd, I; Benn, C; Christian, D; Hrudková, M; Keenan, F P; Steele, I A

2009-01-01

142

WASP-38b: A 6.87 day period exoplanet transiting a bright F-type star  

CERN Document Server

We report the discovery of WASP-38b, a long period transiting planet in an eccentric $6.871815$ day orbit. The transit epoch is $2455335.92050 \\pm 0.00074$ (HJD) and the transit duration is $4.663$ hours. We performed a spectral analysis of the host star HD 146389/BD+10 2980 that yielded $T_{eff} = 6150 \\pm 80 $K, \\logg$=4.3 \\pm 0.1$, \\vsini=$8.6 \\pm 0.4 $\\kms, $M_*=1.16 \\pm 0.04$\\Msun\\ and $R_* =1.36 \\pm 0.05 $\\Rsun, consistent with a dwarf of spectral type F8. The radial velocity variations and the transit light curves were fitted simultaneously to estimate the orbital and planetary parameters. The planet has a mass of $2.71 \\pm 0.07 $ \\Mjup\\ and a radius of $1.08 \\pm 0.05\\, $\\Rjup\\, giving a density, $ \\rho_p = 2.2 \\pm 0.3 \\rho_J$. The high precision of the eccentricity $e=0.032 \\pm 0.0045$ is due to the relative transit timing from the light curves and the RV shape. The planet equilibrium temperature is estimated at $1311 \\pm 45$K. WASP-38b is the longest period planet found by WASP-North and with a brigh...

Barros, S C C; Cameron, A Collier; Lister, T A; McCormac, J; Pollacco, D; Simpson, E K; Smalley, B; Street, R A; Todd, I; Triaud, A H M J; Boisse, I; Bouchy, F; Hebrard, G; Moutou, C; Pepe, F; Queloz, D; Santerne, A; Segransan, D; Udry, S; Bento, J; Butters, O W; Enoch, B; Haswell, C A; Hellier, C; Keenan, F P; Miller, G R M; Moulds, V; Norton, A J; Parley, N; Skillen, I; Watson, C A; West, R G; Wheatley, P J

2010-01-01

143

The APACHE survey hardware and software design: Tools for an automatic search of small-size transiting exoplanets  

Science.gov (United States)

Small-size ground-based telescopes can effectively be used to look for transiting rocky planets around nearby low-mass M stars using the photometric transit method, as recently demonstrated for example by the MEarth project. Since 2008 at the Astronomical Observatory of the Autonomous Region of Aosta Valley (OAVdA), we have been preparing for the long-term photometric survey APACHE, aimed at finding transiting small-size planets around thousands of nearby early and mid-M dwarfs. APACHE (A PAthway toward the Characterization of Habitable Earths) is designed to use an array of five dedicated and identical 40-cm Ritchey-Chretien telescopes and its observations started at the beginning of summer 2012. The main characteristics of the survey final set up and the preliminary results from the first weeks of observations will be discussed.

Christille, Jean-Marc; Bernagozzi, A.; Bertolini, E.; Calcidese, P.; Carbognani, A.; Cenadelli, D.; Damasso, M.; Giacobbe, P.; Lanteri, L.; Lattanzi, M. G.; Sozzetti, A.; Smart, R.

2013-04-01

144

The APACHE survey hardware and software design: Tools for an automatic search of small-size transiting exoplanets  

Directory of Open Access Journals (Sweden)

Full Text Available Small-size ground-based telescopes can effectively be used to look for transiting rocky planets around nearby low-mass M stars using the photometric transit method, as recently demonstrated for example by the MEarth project. Since 2008 at the Astronomical Observatory of the Autonomous Region of Aosta Valley (OAVdA, we have been preparing for the long-term photometric survey APACHE, aimed at finding transiting small-size planets around thousands of nearby early and mid-M dwarfs. APACHE (A PAthway toward the Characterization of Habitable Earths is designed to use an array of five dedicated and identical 40-cm Ritchey-Chretien telescopes and its observations started at the beginning of summer 2012. The main characteristics of the survey final set up and the preliminary results from the first weeks of observations will be discussed.

Lattanzi M.G.

2013-04-01

145

The NASA Exoplanet Archive: Data Inventory Service  

Science.gov (United States)

We present here the latest addition to the NASA Exoplanet Archive - the Data Inventory Service, a tool aimed to provide the user with all the data available within the archive (exoplanet and stellar parameters, time series from ground-based transit surveys (such as Super WASP, XO, HAT-P, KELT), Kepler Pipeline products, CoRoT light curves, etc.) at or near the location of an astronomical object. The NASA Exoplanet Archive is an online service dedicated to compile and to serve public astronomical data sets involved in the search for and characterization of extrasolar planets and their host stars. The data in the archive include stellar parameters (e.g., positions, magnitudes, temperatures, etc.), exoplanet parameters (such as masses and orbital parameters) and discovery/characterization data (e.g., published radial velocity curves, photometric light curves, spectra, etc.). In support of the Kepler Extended Mission, the NASA Exoplanet Archive also hosts data related to Kepler Objects of Interest (KOI), Kepler Pipeline products such as Threshold Crossing Events (TCE) and Data Validation Reports, and Kepler Stellar parameters as used by the Kepler Pipeline. The archive provides tools to work with these data, including interative tables (with plotting capabilities), interactive light curve viewer, periodogram service, transit and ephemeris calculator, and application program interface. To access this information visit us at: http://exoplanetarchive.ipac.caltech.edu

Ramirez, Solange; Akeson, Rachel L.; Ciardi, David R.; Chen, Xi; Christiansen, Jessie; Plavchan, Peter

2014-06-01

146

The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present photometry of 13 transits of XO-3b, a massive transiting planet on an eccentric orbit. Previous data led to two inconsistent estimates of the planetary radius. Our data strongly favor the smaller radius, with increased precision: R_p = 1.217 +/- 0.073 R_Jup. A conflict remains between the mean stellar density determined from the light curve, and the stellar surface gravity determined from the shapes of spectral lines. We argue the light curve should take precedenc...

Winn, Joshua N.; Holman, Matthew J.; Torres, Guillermo; Mccullough, Peter; Johns-krull, Christopher M.; Latham, David W.; Shporer, Avi; Mazeh, Tsevi; Garcia-melendo, Enrique; Foote, Cindy; Esquerdo, Gil; Everett, Mark

2008-01-01

147

Transit spectrophotometry of the exoplanet HD189733b. II. New Spitzer observations at 3.6 microns  

CERN Document Server

We present a new primary transit observation of the hot-jupiter HD189733b, obtained at 3.6 microns with the Infrared Array Camera (IRAC) onboard the Spitzer Space Telescope. Previous measurements at 3.6 microns suffered from strong systematics and conclusions could hardly be obtained with confidence on the water detection by comparison of the 3.6 and 5.8 microns observations. We use a high S/N Spitzer photometric transit light curve to improve the precision of the near infrared radius of the planet at 3.6 microns. The observation has been performed using high-cadence time series integrated in the subarray mode. We are able to derive accurate system parameters, including planet-to-star radius ratio, impact parameter, scale of the system, and central time of the transit from the fits of the transit light curve. We compare the results with transmission spectroscopic models and with results from previous observations at the same wavelength. We obtained the following system parameters: R_p/R_\\star=0.15566+0.00011-...

Desert, J -M; Vidal-Madjar, A; Hebrard, G; Ehrenreich, D; Etangs, A Lecavelier des; Parmentier, V; Ferlet, R; Henry, G W

2010-01-01

148

EXOPLANET CHARACTERIZATION BY PROXY: A TRANSITING 2.15 R? PLANET NEAR THE HABITABLE ZONE OF THE LATE K DWARF KEPLER-61  

International Nuclear Information System (INIS)

We present the validation and characterization of Kepler-61b: a 2.15 R? planet orbiting near the inner edge of the habitable zone of a low-mass star. Our characterization of the host star Kepler-61 is based upon a comparison with a set of spectroscopically similar stars with directly measured radii and temperatures. We apply a stellar prior drawn from the weighted mean of these properties, in tandem with the Kepler photometry, to infer a planetary radius for Kepler-61b of 2.15 ± 0.13 R? and an equilibrium temperature of 273 ± 13 K (given its period of 59.87756 ± 0.00020 days and assuming a planetary albedo of 0.3). The technique of leveraging the physical properties of nearby ''proxy'' stars allows for an independent check on stellar characterization via the traditional measurements with stellar spectra and evolutionary models. In this case, such a check had implications for the putative habitability of Kepler-61b: the planet is 10% warmer and larger than inferred from K-band spectral characterization. From the Kepler photometry, we estimate a stellar rotation period of 36 days, which implies a stellar age of >1 Gyr. We summarize the evidence for the planetary nature of the Kepler-61 transit signal, which we conclude is 30,000 times more likely to be due to a planet than a blend scenario. Finally, we discuss possible compositions for Kepler-61b with a comparison to theoretical models as well as to known exoplanets with similar radii and dynamically measured masses

2013-08-20

149

ECLIPSING BINARY SCIENCE VIA THE MERGING OF TRANSIT AND DOPPLER EXOPLANET SURVEY DATA-A CASE STUDY WITH THE MARVELS PILOT PROJECT AND SuperWASP  

International Nuclear Information System (INIS)

Exoplanet transit and Doppler surveys discover many binary stars during their operation that can be used to conduct a variety of ancillary science. Specifically, eclipsing binary stars can be used to study the stellar mass-radius relationship and to test predictions of theoretical stellar evolution models. By cross-referencing 24 binary stars found in the MARVELS Pilot Project with SuperWASP photometry, we find two new eclipsing binaries, TYC 0272-00458-1 and TYC 1422-01328-1, which we use as case studies to develop a general approach to eclipsing binaries in survey data. TYC 0272-00458-1 is a single-lined spectroscopic binary for which we calculate a mass of the secondary and radii for both components using reasonable constraints on the primary mass through several different techniques. For a primary mass of M1 = 0.92 ± 0.1 Msun, we find M2 = 0.610 ± 0.036 Msun, R1 = 0.932 ± 0.076 Rsun, and R2 = 0.559 ± 0.102 Rsun, and find that both stars have masses and radii consistent with model predictions. TYC 1422-01328-1 is a triple-component system for which we can directly measure the masses and radii of the eclipsing pair. We find that the eclipsing pair consists of an evolved primary star (M1 = 1.163 ± 0.034 Msun, R1 = 2.063 ± 0.058 Rsun) and a G-type dwarf secondary (M2 = 0.905 ± 0.067 Msun, R2 = 0.887 ± 0.037 Rsun). We provide the framework necessary to apply this analysis to much larger data sets.

2011-08-01

150

Horseshoe periodic orbits in the restricted problem of three bodies for a sun-Jupiter mass ratio  

Science.gov (United States)

Segments of seven families of symmetric horseshoe periodic orbits of the restricted three body problem for a sun-Jupiter mass ratio have been numerically determined. Each family is found to have a region consisting of smooth horseshoe shaped orbits with the family evolving to orbits acquiring loops on both sides of the smooth horseshoes. The general evolution of these families is discussed and one in particular (Rabe's horseshoe is a member of this family) is described in more detail with the aid of computer plots of orbits in this family. The smooth horseshoes do not continuously evolve along one family but are members of many distinct families. The change in shape of the smooth horseshoe orbits is examined as they have closer approaches to Jupiter. Each family has a bifurcation with an asymmetric family of periodic orbits. The initial conditions and other quantities describing these bifurcation orbits are given. Starting from these orbits the initial segments of the asymmetric families has been determined.

Taylor, D. B.

1981-11-01

151

Horseshoe periodic orbits in the restricted problem of three bodies for a Sun-Jupiter mass ratio  

Energy Technology Data Exchange (ETDEWEB)

Segments of seven families of symmetric horseshoe periodic orbits of the restricted three body problem for a Sun-Jupiter mass ratio have been numerically determined. Each family is found to have a region consisting of smooth horseshoe shaped orbits with the family evolving to orbits acquiring loops on both sides of the smooth horseshoes. The general evolution of these families is discussed and one in particular (Rabe's horseshoe is a member of this family) is described in more detail with the aid of computer plots of orbits in this family. The smooth horseshoes do not continuously evolve along one family but are members of many distinct families. The change in shape of the smooth horseshoe orbits is examined as they have closer approaches to Jupiter. Each family has a bifuraction with an asymmetric family of periodic orbits. The initial conditions and other quantities describing these bifurcation orbits are given. Starting from these orbits the initial segments of the asymmetric families has been determined. Conjectures are given on the termination of the symmetric families and the existence of other horseshoe families. Some possible physical applications that the smooth horseshoe orbits may have are briefly discussed.

Taylor, D.B.

1981-11-01

152

Discovery of a Bipolar Outflow from 2MASSW J1207334-393254, A 24 Jupiter Mass Brown Dwarf  

CERN Multimedia

The 24 M Jupiter mass brown dwarf 2MASS1207-3932 has for some time been known to show clear signs of classical T Tauri-like accretion. Through analysis of its oxygen forbidden emission we have discovered that it is driving a bipolar outflow. Blue and red-shifted components to the [OI] 6300 forbidden emission line are seen at velocities of - 8 km/s and +4 km/s. Spectro-astrometry recovers the position of both components relative to the BD, at ~ 0.08 arcseconds(in opposing directions). A position velocity diagram of the line region supports the spectro-astrometric results. The H-alpha and HeI 6678 lines were also analysed. These line regions are not offset with respect to the continuum ruling out the presence of spectro-astrometric artifacts and underlining the validity of the [OI] 6300 results. The low radial velocity of the outflow, and relatively large offsets, are consistent with 2MASS1207-3932 having a near edge-on disk, as proposed by Scholz et al. 2MASS1207-3932 is now the smallest mass galactic object k...

Whelan, E T; Randich, S; Baciotti, F; Jayawardhana, R; Testi, L; Natta, A; Mohanty, S

2007-01-01

153

Warm Spitzer Photometry of the Transiting Exoplanets CoRoT-1 and CoRoT-2 at Secondary Eclipse  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We measure secondary eclipses of the hot giant exoplanets CoRoT-1 at 3.6 and 4.5 microns, and CoRoT-2 at 3.6 microns, both using Warm Spitzer. We find that the Warm Spitzer mission is working very well for exoplanet science. For consistency of our analysis we also re-analyze archival cryogenic Spitzer data for secondary eclipses of CoRoT-2 at 4.5 and 8 microns. We compare the total data for both planets, including optical eclipse measurements by the CoRoT mission, and ground...

Deming, Drake; Knutson, Heather; Agol, Eric; Desert, Jean-michel; Burrows, Adam; Fortney, Jonathan J.; Charbonneau, David; Cowan, Nicolas B.; Laughlin, Gregory; Langton, Jonathan; Showman, Adam P.; Lewis, Nikole K.

2010-01-01

154

Current and Future of Microlensing Exoplanet Search  

Science.gov (United States)

Gravitational microlensing has a unique sensitivity to exoplanets at outside of the snow-line with masses down to the Earth-mass. Because of the rarity and short timescale of the planetary signal, the survey groups, MOA-II in New Zealand and OGLE-IV in Chile carry out the wide field survey observation towards the galactic bulge to issue alerts in real time. Then telescopes of the follow-up groups conduct high cadence follow-up observation to get dense sampling of the short planetary signal. Recent high cadence survey observations by MOA-II and OGLE-IV have started to find exoplanets without follow-up observation systematically. This is a transition to the next generation 24-hour high cadence survey network which can reveal the mass function of exoplanets down to Earth-mass outside of the snow-line. The Wide Field Infrared Survey Telescope (WFIRST) is the highest ranked recommendation for a large space mission in the recent New Worlds, New Horizons (NWNH) in Astronomy and Astrophysics 2010 Decadal Survey. Exoplanet microlensing program is one of the primary science of WFIRST. WFIRST will find about 2,000 bound planets and 1,000 unbound planets by the high precision continuous survey with 15 min. cadence. WFIRST can complete the statistical census of planetary systems in the Galaxy, from the outer habitable zone to gravitationally unbound planets - a discovery space inaccessible to other exoplanet detection techniques.

Sumi, Takahiro

2014-04-01

155

Spectra as Windows into Exoplanet Atmospheres  

CERN Document Server

Understanding a planet's atmosphere is a necessary condition for understanding not only the planet itself, but also its formation, structure, evolution, and habitability, This puts a premium on obtaining spectra, and developing credible interpretative tools with which to retrieve vital planetary information. However, for exoplanets these twin goals are far from being realized. In this paper, I provide a personal perspective on exoplanet theory and remote sensing via photometry and low-resolution spectroscopy. Though not a review in any sense, this paper highlights the limitations in our knowledge of compositions, thermal profiles, and the effects of stellar irradiation, focussing on, but not restricted to, transiting giant planets. I suggest that the true function of the recent past of exoplanet atmospheric research has been not to constrain planet properties for all time, but to train a new generation of scientists that, by rapid trial and error, is fast establishing a solid future foundation for a robust sc...

Burrows, Adam

2013-01-01

156

A Search for Alkali Metals in the Atmospheres of Exoplanets  

Science.gov (United States)

The discovery of more than 490 planets orbiting stars other then the Sun (exoplanets) over the past 15 years has confirmed that the Sun is not unique among stars in hosting planets. However, this discovery is only a starting point in the quest to determine if life exists beyond our solar system. By far, most exoplanets have been discovered using the radial velocity technique, which employs the Doppler effect to measure small variations in a star's motion toward and away from the Earth. These motions can be the result of an exoplanet orbiting the star. The second most successful technique, exoplanet transit photometry, is able to detect planets that have orbits passing directly through the line of sight from Earth to the host star, causing a slight apparent dimming of the star during transit. More than 90 transiting exoplanets have been discovered to date. Furthermore, part of the star's light passes through the atmosphere of the planet. The resulting spectrum observed from Earth is the stellar spectrum combined with the transiting planet's atmospheric transmission spectrum. By comparing the out-of-transit pure stellar spectrum with the in-transit star+exoplanetary atmosphere spectrum, the exoplanet's atmospheric transmission spectrum is revealed. Strong atmospheric absorption lines and very high levels of signal-to-noise are required to detect the subtle signatures of the exoplanet's atmosphere. Alkali metals such as sodium (Na) and potassium (K) produce strong atomic absorption lines in the stellar light and should allow the detection of the exoplanet's atmosphere. We are conducting this research utilizing telescope facilities at Moore Observatory near Louisville, Kentucky and Mt. Kent Observatory near Toowoomba in Queensland, Australia. The combination of the northern and southern hemisphere sites provides complete sky coverage.

Collins, Karen; Kielkopf, J.

2010-10-01

157

KOI-200b and KOI-889b: two transiting exoplanets detected and characterized with Kepler, SOPHIE and HARPS-N  

CERN Document Server

We present the detection and characterization of the two new transiting, close-in, giant extrasolar planets KOI-200b and KOI-889b. They were first identified by the Kepler team as promising candidates from photometry of the Kepler satellite, then we established their planetary nature thanks to the radial velocity follow-up jointly secured with the spectrographs SOPHIE and HARPS-N. Combined analyses of the whole datasets allow the two planetary systems to be characterized. The planet KOI-200b has mass and radius of 0.68 +/- 0.09 M_Jup and 1.32 +/- 0.14 R_Jup; it orbits in 7.34 days a F8V host star with mass and radius of 1.40 (+0.14/-0.11) M_Sun and 1.51 +/- 0.14 R_Sun. KOI-889b is a massive planet with mass and radius of 9.9 +/- 0.5 M_Jup and 1.03 +/- 0.06 R_Jup; it orbits in 8.88 days an active G8V star with a rotation period of 19.2 +/- 0.3 days, and mass and radius of 0.88 +/- 0.06 M_Sun and 0.88 +/- 0.04 R_Sun. Both planets lie on eccentric orbits and are located just at the frontier between regimes where...

Hebrard, G; Santerne, A; Deleuil, M; Damiani, C; Bonomo, A S; Bouchy, F; Bruno, G; Diaz, R F; Montagnier, G; Moutou, C

2013-01-01

158

Transiting exoplanets from the CoRoT space mission: XXIV. CoRoT-24: A transiting multi-planet system  

CERN Document Server

We present the discovery of a candidate multiply-transiting system, the first one found in the CoRoT mission. Two transit-like features with periods of 5.11 and 11.76d are detected in the CoRoT light curve, around a main sequence K1V star of r=15.1. If the features are due to transiting planets around the same star, these would correspond to objects of 3.7$\\pm$0.4 and 5.0$\\pm$0.5 R_earth respectively. Several radial velocities serve to provide an upper limit of 5.7 M_earth for the 5.11~d signal, and to tentatively measure a mass of 28$^{+11}_{-11}$ M_earth for the object transiting with a 11.76~d period. These measurements imply low density objects, with a significant gaseous envelope. The detailed analysis of the photometric and spectroscopic data serve to estimate the probability that the observations are caused by transiting Neptune-sized planets as $>$26$\\times$ higher than a blend scenario involving only one transiting planet, and $>$900$\\times$ higher than a scenario involving two blends and no planets....

Alonso, R; Endl, M; Almenara, J M; Guenther, E W; Deleuil, M; Hatzes, A; Aigrain, S; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Bordé, P; Bouchy, F; Cavarroc, C; Cabrera, J; Carpano, S; Csizmadia, Sz; Cochran, W D; Deeg, H J; Díaz, R F; Dvorak, R; Erikson, A; Ferraz-Mello, S; Fridlund, M; Fruth, T; Gandolfi, D; Gillon, M; Grziwa, S; Guillot, T; Hébrard, G; Jorda, L; Léger, A; Lammer, H; Lovis, C; MacQueen, P J; Mazeh, T; Ofir, A; Ollivier, M; Pasternacki, T; Patzold, M; Queloz, D; Rauer, H; Rouan, D; Santerne, A; Schneider, J; Santos, M Tadeu dos; Tingley, B; Titz-Weider, R; Weingrill, J; Wuchterl, G

2014-01-01

159

Synthesizing Exoplanet Demographics from Radial Velocity and Microlensing Surveys, I: Methodology  

CERN Document Server

Motivated by the order-of-magnitude difference in the frequency of giant planets orbiting M dwarfs inferred by microlensing and radial velocity (RV) surveys, we present a method for comparing the statistical constraints on exoplanet demographics inferred from these methods. We first derive the mapping from the observable parameters of a microlensing-detected planet to those of an analogous planet orbiting an RV-monitored star. Using this mapping, we predict the distribution of RV observables for the planet population inferred from microlensing surveys, taking care to adopt reasonable priors for, and properly marginalize over, the unknown physical parameters of microlensing-detected systems. Finally, we use simple estimates of the detection limits for a fiducial RV survey to predict the number and properties of analogs of the microlensing planet population such an RV survey should detect. We find that RV and microlensing surveys have some overlap, specifically for super-Jupiter mass planets ($m_p \\gtrsim 1~M_{...

Clanton, Christian

2014-01-01

160

Transiting exoplanets from the CoRoT space mission. III. The spectroscopic transit of CoRoT-Exo-2b with SOPHIE and HARPS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report on the spectroscopic transit of the massive hot-Jupiter CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE and HARPS. By modeling the radial velocity anomaly occurring during the transit due to the Rossiter-McLaughlin (RM) effect, we determine the sky-projected angle between the stellar spin and the planetary orbital axis to be close to zero lambda = 7.2 ± 4.5 deg, and we secure the planetary nature of CoRoT-Exo-2b. We discuss the influence of the stellar activity o...

2008-01-01

 
 
 
 
161

Transiting exoplanets from the CoRoT space mission III. The spectroscopic transit of CoRoT-Exo-2b with SOPHIE and HARPS  

CERN Document Server

We report on the spectroscopic transit of the massive hot-Jupiter CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE and HARPS. By modeling the radial velocity anomaly occurring during the transit due to the Rossiter-McLaughlin (RM) effect, we determine the sky-projected angle between the stellar spin and the planetary orbital axis to be close to zero lambda=7.2+-4.5 deg, and we secure the planetary nature of CoRoT-Exo-2b. We discuss the influence of the stellar activity on the RM modeling. Spectral analysis of the parent star from HARPS spectra are presented.

Bouchy, F; Deleuil, M; Loeillet, B; Hatzes, A P; Aigrain, S; Alonso, R; Auvergne, M; Baglin, A; Barge, P; Benz, W; Bordé, P; Deeg, H J; De la Reza, R; Dvorak, R; Erikson, A; Fridlund, M; Gondoin, P; Guillot, T; Hébrard, G; Jorda, L; Lammer, H; Léger, A; Llebaria, A; Magain, P; Mayor, M; Moutou, C; Ollivier, M; Pätzold, M; Pepe, F; Pont, F; Rauer, H; Rouan, D; Schneider, J; Triaud, A H M J; Udry, S; Wuchterl, G

2008-01-01

162

Fundamental Parameters of Exoplanets and Their Host Stars  

CERN Document Server

For much of human history we have wondered how our solar system formed, and whether there are any other planets like ours around other stars. Only in the last 20 years have we had direct evidence for the existence of exoplanets, with the number of known exoplanets dramatically increasing in recent years, especially with the success of the Kepler mission. Observations of these systems are becoming increasingly more precise and numerous, thus allowing for detailed studies of their masses, radii, densities, temperatures, and atmospheric compositions. However, one cannot accurately study exoplanets without examining their host stars in equal detail, and understanding what assumptions must be made to calculate planetary parameters from the directly derived observational parameters. In this thesis, I present observations and models of the primary transits and secondary eclipses of transiting exoplanets from both the ground and Kepler in order to better study their physical characteristics and search for additional ...

Coughlin, Jeffrey L

2013-01-01

163

SOPHIE velocimetry of $\\textit{Kepler}$ transit candidates XII. KOI-1257 b: a highly-eccentric 3-month period transiting exoplanet  

CERN Document Server

In this paper we report a new transiting warm giant planet: KOI-1257 b. It was first detected in photometry as a planet-candidate by the $\\textit{Kepler}$ space telescope and then validated thanks to a radial velocity follow-up with the SOPHIE spectrograph. It orbits its host star with a period of 86.647661 d $\\pm$ 3 s and a high eccentricity of 0.772 $\\pm$ 0.045. The planet transits the main star of a metal-rich, relatively old binary system with stars of mass of 0.99 $\\pm$ 0.05 Msun and 0.70 $ \\pm $ 0.07 Msun for the primary and secondary (respectively). This binary system is constrained thanks to a self-consistent modelling of the $\\textit{Kepler}$ transit light curve, the SOPHIE radial velocities, line bisector and full-width half maximum (FWHM) variations as well as the spectral energy distribution. However, future observations are needed to confirm it. The PASTIS fully-Bayesian software was used to validate the nature of the planet and to determine which star of the binary system is the transit host. By...

Santerne, A; Deleuil, M; Havel, M; Correia, A C M; Almenara, J -M; Alonso, R; Arnold, L; Barros, S C C; Behrend, R; Bernasconi, L; Boisse, I; Bonomo, A S; Bouchy, F; Bruno, G; Damiani, C; Díaz, R F; Gravallon, D; Guillot, T; Labrevoir, O; Montagnier, G; Moutou, C; Rinner, C; Santos, N C; Abe, L; Audejean, M; Bendjoya, P; Gillier, C; Gregorio, J; Martinez, P; Michelet, J; Montaigut, R; Poncy, R; Rivet, J -P; Rousseau, G; Roy, R; Suarez, O; Vanhuysse, M; Verilhac, D

2014-01-01

164

Exoplanets Detection, Formation, Properties, Habitability  

CERN Document Server

This edited, multi-author volume will be an invaluable introduction and reference to all key aspects in the field of exoplanet research. The reviews cover: Detection methods and properties of known exoplanets, Detection of extrasolar planets by gravitational microlensing. The formation and evolution of terrestrial planets in protoplanetary and debris disks. The brown dwarf-exoplanet connection. Formation, migration mechanisms and properties of hot Jupiters. Dynamics of multiple exoplanet systems. Doppler exoplanet surveys. Searching for exoplanets in the stellar graveyard. Formation and habitability of extra solar planets in multiple star systems. Exoplanet habitats and the possibilities for life. Moons of exoplanets: habitats for life. Contributing authors: •Rory Barnes •David P. Bennett •Jian Ge •Nader Haghighipour •Patrick Irwin •Hugh Jones •Victoria Meadows •Stanimir Metchev •I. Neill Reid •George Rieke •Caleb Scharf •Steinn Sigurdsson

Mason, John W

2008-01-01

165

Variable Star and Exoplanet Section of the Czech Astronomical Society  

Science.gov (United States)

We present activities of Czech variable star observers organized in the Variable Star and Exoplanet Section of the Czech Astronomical Society. We work in four observing projects: B.R.N.O. - eclipsing binaries, MEDUZA - intrinsic variable stars, TRESCA - transiting exoplanets and candidates, HERO - objects of high energy astrophysics. Detailed information together with O-C gate (database of eclipsing binaries minima timings) and OEJV (Open European Journal on Variable stars) are available on our internet portal http://var.astro.cz.

Brát, L.; Zejda, M.

2010-12-01

166

Atmospheric Circulation of Exoplanets  

CERN Document Server

We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from Solar-System studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric d...

Showman, Adam P; Menou, Kristen

2009-01-01

167

Current status of the Qatar Exoplanet Survey  

Science.gov (United States)

The Qatar Exoplanet Survey (QES) is conducting a wide-field transit search program using a 6-camera CCD imaging system designed design to go at least 0.5 magnitudes fainter than most current wide-angle surveys such as SuperWASP and HATNet. QES uses two overlapping wide field 135mm and 200mm lenses along with four 400mm lenses mosaiced to cover the same 11x11 degree field of view. The higher angular resolution and large aperture doubles the sampling volume for low-mass stars, compared to WASP and HAT. Saturn and Neptune sized planets are more easily detected if they orbit smaller stars, therefore by extending the transit search to stars with smaller radii QES is well position to plug the gap, between SuperEarths and Hot Jupiters, left between Kepler and the current wide-angle surveys. QES detections are nonetheless still bright enough for radial-velocity follow up with 2-m and 4-m class telescopes. We present the current status of the Qatar Exoplanet Survey, along with information of the first transiting exoplanets, Qatar-1b and Qatar-2b, to be found using the instrument, which were both detected orbiting K-dwarfs stars.

Parley, Neil; Collier Cameron, A.; Horne, K.; Alsubai, K. A.; QES Consortium

2011-09-01

168

Warm Spitzer Photometry of the Transiting Exoplanets CoRoT-1 and CoRoT-2 at Secondary Eclipse  

CERN Multimedia

We measure secondary eclipses of the hot giant exoplanets CoRoT-1 at 3.6 and 4.5 microns, and CoRoT-2 at 3.6 microns, both using Warm Spitzer. We find that the Warm Spitzer mission is working very well for exoplanet science. For consistency of our analysis we also re-analyze archival cryogenic Spitzer data for secondary eclipses of CoRoT-2 at 4.5 and 8 microns. We compare the total data for both planets, including optical eclipse measurements by the CoRoT mission, and ground-based eclipse measurements at 2 microns, to existing models. Both planets exhibit stronger eclipses at 4.5 than at 3.6 microns, which is often indicative of an atmospheric temperature inversion. The spectrum of CoRoT-1 is best reproduced by a 2460K blackbody, due either to a high altitude layer that strongly absorbs stellar irradiance, or an isothermal region in the planetary atmosphere. The spectrum of CoRoT-2 is unusual because the 8 micron contrast is anomalously low. Non-inverted atmospheres could potentially produce the CoRoT-2 spect...

Deming, Drake; Agol, Eric; Desert, Jean-Michel; Burrows, Adam; Fortney, Jonathan J; Charbonneau, David; Cowan, Nicolas B; Laughlin, Gregory; Langton, Jonathan; Showman, Adam P; Lewis, Nikole K

2010-01-01

169

Chemical modeling of exoplanet atmospheres  

CERN Document Server

The past twenty years have revealed the diversity of planets that exist in the Universe. It turned out that most of exoplanets are different from the planets of our Solar System and thus, everything about them needs to be explored. Thanks to current observational technologies, we are able to determine some information about the atmospheric composition, the thermal structure and the dynamics of these exoplanets, but many questions remain still unanswered. To improve our knowledge about exoplanetary systems, more accurate observations are needed and that is why the Exoplanet Characterisation Observatory (EChO) is an essential space mission. Thanks to its large spectral coverage and high spectral resolution, EChO will provide exoplanetary spectra with an unprecedented accuracy, allowing to improve our understanding of exoplanets. In this work, we review what has been done to date concerning the chemical modeling of exoplanet atmospheres and what are the main characteristics of warm exoplanet atmospheres, which a...

Venot, Olivia

2014-01-01

170

Using SPICA Space Telescope to characterize Exoplanets  

CERN Document Server

We present the 3.5m SPICA space telescope, a proposed Japanese-led JAXA-ESA mission scheduled for launch around 2017. The actively cooled ( 18 um). SPICA is one of the few space missions selected to go to the next stage of ESA's Cosmic Vision 2015-2025 selection process. In this White Paper we present the main specifications of the three instruments currently baselined for SPICA: a mid-infrared (MIR) coronagraph (~3.5 to ~27 um) with photometric and spectral capabilities (R~200), a MIR wide-field camera and high resolution spectrometer (R~30,000), and a far-infrared (FIR ~30 to ~210 um) imaging spectrometer - SAFARI - led by a European consortium. We discuss their capabilities in the context of MIR direct observations of exo-planets (EPs) and multiband photometry/high resolution spectroscopy observations of transiting exo-planets. We conclude that SPICA will be able to characterize the atmospheres of transiting exo-planets down to the super-Earth size previously detected by ground- or space-based observatorie...

Goicoechea, J R; Tinetti, G; Nakagawa, T; Enya, K; Tamura, M; Ferlet, M; Isaak, K G; Wyatt, M; Aylward, A D; Barlow, M; Beaulieu, J P; Boccaletti, A; Cernicharo, J; Cho, J; Claudi, R; Jones, H; Lammer, H; Léger, A; Martín-Pintado, J; Miller, S; Najarro, F; Pinfield, D; Schneider, J; Selsis, F; Stam, D M; Tennyson, J; Viti, S; White, G

2008-01-01

171

DIRECT IMAGING OF A COLD JOVIAN EXOPLANET IN ORBIT AROUND THE SUN-LIKE STAR GJ 504  

Energy Technology Data Exchange (ETDEWEB)

Several exoplanets have recently been imaged at wide separations of >10 AU from their parent stars. These span a limited range of ages (<50 Myr) and atmospheric properties, with temperatures of 800-1800 K and very red colors (J - H > 0.5 mag), implying thick cloud covers. Furthermore, substantial model uncertainties exist at these young ages due to the unknown initial conditions at formation, which can lead to an order of magnitude of uncertainty in the modeled planet mass. Here, we report the direct-imaging discovery of a Jovian exoplanet around the Sun-like star GJ 504, detected as part of the SEEDS survey. The system is older than all other known directly imaged planets; as a result, its estimated mass remains in the planetary regime independent of uncertainties related to choices of initial conditions in the exoplanet modeling. Using the most common exoplanet cooling model, and given the system age of 160{sup +350}{sub -60} Myr, GJ 504b has an estimated mass of 4{sup +4.5}{sub -1.0} Jupiter masses, among the lowest of directly imaged planets. Its projected separation of 43.5 AU exceeds the typical outer boundary of {approx}30 AU predicted for the core accretion mechanism. GJ 504b is also significantly cooler (510{sup +30}{sub -20} K) and has a bluer color (J - H = -0.23 mag) than previously imaged exoplanets, suggesting a largely cloud-free atmosphere accessible to spectroscopic characterization. Thus, it has the potential of providing novel insights into the origins of giant planets as well as their atmospheric properties.

Kuzuhara, M. [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Tamura, M.; Kandori, R.; Hori, Y.; Suzuki, R.; Suenaga, T.; Takahashi, Y. H.; Kwon, J. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kudo, T. [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A' ohoku Place, Hilo, HI 96720 (United States); Janson, M.; Brandt, T. D.; Spiegel, D.; Burrows, A.; Turner, E. L.; Moro-Martin, A. [Department of Astrophysical Sciences, Princeton University, Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States); Thalmann, C. [Astronomical Institute ' ' Anton Pannekoek' ' , University of Amsterdam, Postbus 94249, 1090 GE, Amsterdam (Netherlands); Biller, B.; Henning, T. [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Carson, J. [Department of Physics and Astronomy, College of Charleston, 58 Coming Street, Charleston, SC 29424 (United States); McElwain, M. W., E-mail: m.kuzuhara@nao.ac.jp [Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others

2013-09-01

172

Transiting exoplanets from the CoRoT space mission. XVII. The hot Jupiter CoRoT-17b: a very old planet  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report on the discovery of a hot Jupiter-type exoplanet, CoRoT-17b, detected by the CoRoT satellite. It has a mass of 2.43 ± 0.30 M[SUB]Jup[/SUB] and a radius of 1.02 ± 0.07 R[SUB]Jup[/SUB], while its mean density is 2.82 ± 0.38 g/cm[SUP]3[/SUP]. CoRoT-17b is in a circular orbit with a period of 3.7681 ± 0.0003 days. The host star is an old (10.7 ± 1.0 Gyr) main-sequence star, which makes it an intriguing object for planetary evolution studies. The planet's internal composition is not...

2011-01-01

173

Atmospheric Dynamics of Exoplanets  

CERN Document Server

The characterization of exoplanetary atmospheres has come of age in the last decade, as astronomical techniques now allow for albedos, chemical abundances, temperature profiles and maps, rotation periods and even wind speeds to be measured. Atmospheric dynamics sets the background state of density, temperature and velocity that determines or influences the spectral and temporal appearance of an exoplanetary atmosphere. Hot exoplanets are most amenable to these characterization techniques; in the present review, we focus on highly-irradiated, large exoplanets (the "hot Jupiters"), as astronomical data begin to confront theoretical questions. We summarize the basic atmospheric quantities inferred from the astronomical observations. We review the state of the art by addressing a series of current questions and look towards the future by considering a separate set of exploratory questions. Attaining the next level of understanding will require a concerted effort of constructing multi-faceted, multi-wavelength dat...

Heng, Kevin

2014-01-01

174

Families of asymmetric periodic solutions of the restricted problem of three bodies for the sun-Jupiter mass ratio and their relationship with the symmetric families.  

Science.gov (United States)

Message derived a method to detect bifurcations of a family of asymmetric periodic solutions from a family of symmetric periodic solutions in the restricted problem of three bodies for the limiting case when the second body has zero mass. This is used to examine several small integer commensurabilities. A total of 21 exterior and 21 interior small integer commensurabilities are examined and bifurcations (two in number) are found to exist only for exterior commensurabilities (q+1):1, q = 1,2,...,7. On investigating other commensurabilities of this form for values of q up to 50 two bifurcations are still found to exist for each. For a Sun-Jupiter mass-ratio the complete family of asymmetric periodic solutions associated with q = 1,2,...,5, and the initial segments of the asymmetric family with q = 6,7,...,12, have been numerically determined.

Taylor, D. B.

1983-01-01

175

The NStED Stellar and Exoplanet Hosting Star Service  

CERN Document Server

The NASA Star and Exoplanet Database (NStED) is a general purpose stellar archive with the aim of providing support for NASA's planet finding and characterization goals, stellar astrophysics, and the planning of NASA and other space missions. There are two principal components of NStED: a database of (currently) 140,000 nearby stars and exoplanet-hosting stars, and an archive dedicated to high precision photometric surveys for transiting exoplanets. We present a summary of the NStED stellar database, functionality, tools, and user interface. NStED currently serves the following kinds of data for 140,000 stars (where available): coordinates, multiplicity, proper motion, parallax, spectral type, multiband photometry, radial velocity, metallicity, chromospheric and coronal activity index, and rotation velocity/period. Furthermore, the following derived quantities are given wherever possible: distance, effective temperature, mass, radius, luminosity, space motions, and physical/angular dimensions of habitable zon...

Ramírez, S; Baker, R; Berriman, G B; Von Braun, K; Chiu, N-M; Ciardi, D R; Good, J; Kane, S R; Laity, A C; McElroy, D L; Monkewitz, S; Payne, A N; Schmitz, M; Stauffer, J R; Wyatt, P L; Zhang, A

2008-01-01

176

Directed follow-up strategy of low-cadence photometric surveys in Search of transiting exoplanets - I. Bayesian approach for adaptive scheduling  

CERN Document Server

We propose a novel approach to utilize low-cadence photometric surveys for exoplanetary transit search. Even if transits are undetectable in the survey database alone, it can still be useful for finding preferred times for directed follow-up observations that will maximize the chances to detect transits. We demonstrate the approach through a few simulated cases. These simulations are based on the Hipparcos Epoch Photometry data base, and the transiting planets whose transits were already detected there. In principle, the approach we propose will be suitable for the directed follow-up of the photometry from the planned Gaia mission, and it can hopefully significantly increase the yield of exoplanetary transits detected, thanks to Gaia.

Dzigan, Yifat

2011-01-01

177

Tidal Evolution of Exoplanets  

CERN Document Server

Tidal effects arise from differential and inelastic deformation of a planet by a perturbing body. The continuous action of tides modify the rotation of the planet together with its orbit until an equilibrium situation is reached. It is often believed that synchronous motion is the most probable outcome of the tidal evolution process, since synchronous rotation is observed for the majority of the satellites in the Solar System. However, in the 19th century, Schiaparelli also assumed synchronous motion for the rotations of Mercury and Venus, and was later shown to be wrong. Rather, for planets in eccentric orbits synchronous rotation is very unlikely. The rotation period and axial tilt of exoplanets is still unknown, but a large number of planets have been detected close to the parent star and should have evolved to a final equilibrium situation. Therefore, based on the Solar System well studied cases, we can make some predictions for exoplanets. Here we describe in detail the main tidal effects that modify the...

Correia, Alexandre C M

2010-01-01

178

M Dwarf Flares: Exoplanet Detection Implications  

Science.gov (United States)

Low mass stars such as M dwarfs have become prime targets for exoplanet transit searches as their low luminosities and small stellar radii could enable the detection of super-Earths residing in their habitable zones. While promising transit targets, M dwarfs are also inherently variable and can exhibit up to ˜6 magnitude flux enhancements in the optical U-band. This is significantly higher than the predicted transit depths of habitable zone super-Earths (0.005 magnitude flux decrease). The behavior of flares at infrared (IR) wavelengths, particularly those likely to be used to study and characterize M dwarf exoplanets using facilities such as the James Web Space Telescope (JWST), remains largely unknown. To address these uncertainties, we are executing a coordinated, contemporaneous monitoring program of the optical and IR flux of M dwarfs known to regularly flare. A suite of telescopes located at the Kitt Peak National Observatory and the Apache Point Observatory are used for the observations. We present the initial results of this program.

Tofflemire, B. M.; Wisniewski, J. P.; Hilton, E. J.; Kowalski, A. F.; Kundurthy, P.; Schmidt, S. J.; Hawley, S. L.; Holtzman, J. A.

2011-12-01

179

A Computational Tool to Interpret the Bulk Composition of Solid Exoplanets based on Mass and Radius Measurements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The prospects for finding transiting exoplanets in the range of a few to 20 Earth masses is growing rapidly with both ground-based and spaced-based efforts. We describe a publicly available computer code to compute and quantify the compositional ambiguities for differentiated solid exoplanets with a measured mass and radius, including the mass and radius uncertainties.

Zeng, Li; Seager, Sara

2008-01-01

180

Transiting exoplanets from the CoRoT space mission. XVII. The hot Jupiter CoRoT-17b: a very old planet  

Science.gov (United States)

We report on the discovery of a hot Jupiter-type exoplanet, CoRoT-17b, detected by the CoRoT satellite. It has a mass of 2.43 ± 0.30 MJup and a radius of 1.02 ± 0.07 RJup, while its mean density is 2.82 ± 0.38 g/cm3. CoRoT-17b is in a circular orbit with a period of 3.7681 ± 0.0003 days. The host star is an old (10.7 ± 1.0 Gyr) main-sequence star, which makes it an intriguing object for planetary evolution studies. The planet's internal composition is not well constrained and can range from pure H/He to one that can contain ~380 earth masses of heavier elements. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain. Part of the observations were obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. Based on observations made with HARPS spectrograph on the 3.6-m European Organisation for Astronomical Research in the Southern Hemisphere telescope at La Silla Observatory, Chile (ESO program 184.C-0639). Based on observations made with the IAC80 telescope operated on the island of Tenerife by the Instituto de Astrofísica de Canarias in the Spanish Observatorio del Teide. Part of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

Csizmadia, Sz.; Moutou, C.; Deleuil, M.; Cabrera, J.; Fridlund, M.; Gandolfi, D.; Aigrain, S.; Alonso, R.; Almenara, J.-M.; Auvergne, M.; Baglin, A.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Bruntt, H.; Carone, L.; Carpano, S.; Cavarroc, C.; Cochran, W.; Deeg, H. J.; Díaz, R. F.; Dvorak, R.; Endl, M.; Erikson, A.; Ferraz-Mello, S.; Fruth, Th.; Gazzano, J.-C.; Gillon, M.; Guenther, E. W.; Guillot, T.; Hatzes, A.; Havel, M.; Hébrard, G.; Jehin, E.; Jorda, L.; Léger, A.; Llebaria, A.; Lammer, H.; Lovis, C.; MacQueen, P. J.; Mazeh, T.; Ollivier, M.; Pätzold, M.; Queloz, D.; Rauer, H.; Rouan, D.; Santerne, A.; Schneider, J.; Tingley, B.; Titz-Weider, R.; Wuchterl, G.

2011-07-01

 
 
 
 
181

Transiting exoplanets from the CoRoT space mission. XXI. CoRoT-19b: a low density planet orbiting an old inactive F9V-star  

DEFF Research Database (Denmark)

Context. Observations of transiting extrasolar planets are of key importance to our understanding of planets because their mass, radius, and mass density can be determined. These measurements indicate that planets of similar mass can have very different radii. For low-density planets, it is generally assumed that they are inflated owing to their proximity to the host-star. To determine the causes of this inflation, it is necessary to obtain a statistically significant sample of planets with precisely measured masses and radii. Aims. The CoRoT space mission allows us to achieve a very high photometric accuracy. By combining CoRoT data with high-precision radial velocity measurements, we derive precise planetary radii and masses. We report the discovery of CoRoT-19b, a gas-giant planet transiting an old, inactive F9V-type star with a period of four days. Methods. After excluding alternative physical configurations mimicking a planetary transit signal, we determine the radius and mass of the planet by combining CoRoT photometry with high-resolution spectroscopy obtained with the echelle spectrographs SOPHIE, HARPS, FIES, and SANDIFORD. To improve the precision of its ephemeris and the epoch, we observed additional transits with the TRAPPIST and Euler telescopes. Using HARPS spectra obtained during the transit, we then determine the projected angle between the spin of the star and the orbit of the planet. Results. We find that the host star of CoRoT-19b is an inactive F9V-type star close to the end of its main-sequence life. The host star has a mass Mâ?? = 1.21 ± 0.05 â??Mâ?? and radius Râ?? = 1.65 â??±â?? 0.04â??Râ??. The planet has a mass of MP = 1.11 ± 0.06â??MJup and radius of RP = 1.29 â??± 0.03â??RJup. The resulting bulk density is only ρ = 0.71 â??± 0.06â??gâ??cm-3, which is much lower than that for Jupiter. Conclusions. The exoplanet CoRoT-19b is an example of a giant planet of almost the same mass as Jupiter but a â??30% larger radius.

Guenther, E. W.; Díaz, R. F.

2012-01-01

182

Atmospheric Circulation of Terrestrial Exoplanets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide r...

Showman, Adam P.; Wordsworth, Robin D.; Merlis, Timothy M.; Kaspi, Yohai

2013-01-01

183

Characterization of exoplanet hosts  

Directory of Open Access Journals (Sweden)

Full Text Available Spectroscopic analysis of exoplanet hosts and the stellar sample from which they are drawn provides abundances and other properties that quantitively constrain models of planet formation. The program Spectroscopy Made Easy (SME determines stellar parameters by fitting observed spectra, though line lists must be selected wisely. For giant planets, it is now well established that stars with higher metallicity are more likely to have detected companions. Stellar metallicity does not seem to affect the formation and/or migration of detectable planets less massive than Neptune, especially when considering only the most massive planet in the system. In systems with at least one planet less than 10 times the mass of Earth, the mass of the most massive planet increases dramatically with host star metallicity. This may reflect metallicity dependent timescales for core formation, envelope accretion, and/or migration into the detection zone.

Valenti Jeff A.

2013-04-01

184

WASP-54b, WASP-56b and WASP-57b: Three new sub-Jupiter mass planets from SuperWASP  

CERN Document Server

We present three newly discovered sub-Jupiter mass planets from the SuperWASP survey: WASP-54b is a heavily bloated planet of mass 0.636$^{+0.025}_{-0.024}$ \\mj and radius 1.653$^{+0.090}_{-0.083}$ \\rj. It orbits a F9 star, evolving off the main sequence, every 3.69 days. Our MCMC fit of the system yields a slightly eccentric orbit ($e=0.067^{+0.033}_{-0.025}$) for WASP-54b. We investigated further the veracity of our detection of the eccentric orbit for WASP-54b, and we find that it could be real. However, given the brightness of WASP-54 V=10.42 magnitudes, we encourage observations of a secondary eclipse to draw robust conclusions on both the orbital eccentricity and the thermal structure of the planet. WASP-56b and WASP-57b have masses of 0.571$^{+0.034}_{-0.035}$ \\mj and $0.672^{+0.049}_{-0.046}$ \\mj, respectively; and radii of $1.092^{+0.035}_{-0.033}$ \\rj for WASP-56b and $0.916^{+0.017}_{-0.014}$ \\rj for WASP-57b. They orbit main sequence stars of spectral type G6 every 4.67 and 2.84 days, respectively...

Faedi, F; Barros, S C C; Brown, D; Cameron, A Collier; Doyle, A P; Gillon, M; Chew, Y Gomez Maqueo; Hebrard, G; Lendl, M; Liebig, C; Smalley, B; Triaud, A H M J; West, R G; Wheatley, P J; Alsubai, K A; Anderson, D R; Armstrong, D J; Bento, J; Bochinski, J; Bouchy, F; Busuttil, R; Fossati, L; Fumel, A; Haswell, C A; Hellier, C; Holmes, S; Jehin, E; Kolb, U; McCormac, J; Miller, G R M; Moutou, C; Norton, A J; Parley, N; Queloz, D; Skillen, I; Smith, A M S; Udry, S; Watson, C

2012-01-01

185

Transiting exoplanets from the CoRoT space mission - XIX. CoRoT-23b: a dense hot Jupiter on an eccentric orbit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report the detection of CoRoT-23b, a hot Jupiter transiting in front of its host star with a period of 3.6314 \\pm 0.0001 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite, combined with spectroscopic radial velocity (RV) measurements. A photometric search for possible background eclipsing binaries conducted at CFHT and OGS concluded with a very low risk of false positives. The usual techniques of combining RV and transit data simultaneously were u...

2011-01-01

186

Transiting exoplanets from the CoRoT space mission. VII. The ``hot-Jupiter''-type planet CoRoT-5b  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Aims: The CoRoT space mission continues to photometrically monitor about 12 000 stars in its field-of-view for a series of target fields to search for transiting extrasolar planets ever since 2007. Deep transit signals can be detected quickly in the â alarm-modeâ in parallel to the ongoing target field monitoring. CoRoT's first planets have been detected in this mode. Methods: The CoRoT raw lightcurves are filtered for orbital residuals, outliers, and low-frequency stellar signals...

2009-01-01

187

Results from the Exoplanet Search Programmes with BEST and TEST  

CERN Document Server

Thueringer Landessternwarte Tautenburg (TLS) has started to operate a small dedicated telescope - the Tautenburg Exoplanet Search Telescope (TEST) - searching for transits of extrasolar planets in photometric time series observations. In a joint effort with the Berlin Exoplanet Search Telescope (BEST) operated by the Institut fuer Planetenforschung of the "Deutsches Zentrum fuer Luft- und Raumfahrt (DLR)" at the Observatoire de Haute-Provence (OHP), France, two observing sites are used to optimise transit search. Here, we give a short overview of these systems and the data analysis. We describe a software pipeline that we have set up to identify transit events of extrasolar planets and variable stars in time series data from these and other telescopes, and report on some first results.

Eislöffel, J; Rauer, H; Voss, H; Erikson, A; Eigmueller, P; Günther, E; Eisloeffel, Jochen; Hatzes, Artie P.; Rauer, Heike; Voss, Holger; Erikson, Anders; Eigmueller, Philipp; Guenther, Eike

2006-01-01

188

Constraints on Secondary Eclipse Probabilities of Long-Period Exoplanets from Orbital Elements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Long-period transiting exoplanets provide an opportunity to study the mass-radius relation and internal structure of extrasolar planets. Their studies grant insights into planetary evolution akin to the Solar System planets, which, in contrast to hot Jupiters, are not constantly exposed to the intense radiation of their parent stars. Observations of secondary eclipses allow investigations of exoplanet temperatures and large-scale exo-atmospheric properties. In this short pap...

Von Braun, Kaspar; Kane, Stephen R.

2009-01-01

189

Transiting exoplanets from the CoRoT space mission VI. CoRoT-Exo-3b: The first secure inhabitant of the brown-dwarf desert  

CERN Document Server

Context. The CoRoT space mission routinely provides high-precision photometric measurements of thousands of stars that have been continuously observed for months. Aims. The discovery and characterization of the first very massive transiting planetary companion with a short orbital period is reported. Methods. A series of 34 transits was detected in the CoRoT light curve of an F3V star, observed from May to October 2007 for 152 days. The radius was accurately determined and the mass derived for this new transiting, thanks to the combined analysis of the light curve and complementary ground-based observations: high-precision radial-velocity measurements, on-off photometry, and high signal-to-noise spectroscopic observations. Results. CoRoT-Exo-3b has a radius of 1.01+-0.07 RJup and transits around its F3-type primary every 4.26 days in a synchronous orbit. Its mass of 21.66+-1.0 MJup, density of 26.4+-5.6 g cm^-3, and surface gravity of log g = 4.72 clearly distinguish it from the regular close-in planet popula...

Deleuil, M; Alonso, R; Bouchy, F; Rouan, D

2008-01-01

190

Transiting exoplanets from the CoRoT space mission. X. CoRoT-10b: a giant planet in a 13.24 day eccentric orbit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Context. The space telescope CoRoT searches for transiting extrasolar planets by continuously monitoring the optical flux of thousands of stars in several fields of view. Aims: We report the discovery of CoRoT-10b, a giant planet on a highly eccentric orbit (e = 0.53 ± 0.04) revolving in 13.24 days around a faint (V = 15.22) metal-rich K1V star. Methods: We used CoRoT photometry, radial velocity observations taken with the HARPS spectrograph, and UVES spectra of the parent star...

2010-01-01

191

Doppler tomography of transiting exoplanets: A prograde, low-inclined orbit for the hot Jupiter CoRoT-11b  

CERN Multimedia

We report the detection of the Doppler shadow of the transiting hot Jupiter CoRoT-11b. Our analysis is based on line-profile tomography of time-series, Keck/HIRES high-resolution spectra acquired during the transit of the planet. We measured a sky-projected, spin-orbit angle of 0.1 +/- 2.6 degrees, which is consistent with a very low-inclined orbit with respect to the stellar rotation axis. We refined the physical parameters of the system using a Markov chain Monte Carlo simultaneous fitting of the available photometric and spectroscopic data. An analysis of the tidal evolution of the system shows how the currently measured obliquity and its uncertainty translate into an initial absolute value of less than about 10 degrees on the zero-age main sequence, for an expected average modified tidal quality factor of the star Q'* > 4 x 10^6. This is indicative of an inward migration scenario that would not have perturbed the primordial low obliquity of CoRoT-11b. Taking into account the effective temperature and mass...

Gandolfi, Davide; Endl, Michael; Lanza, Antonino F; Damiani, Cilia; Alonso, Roi; Cochran, William D; Deleuil, Magali; Fridlund, Malcolm; Hatzes, Artie P; Guenther, Eike W

2012-01-01

192

The exoplanet microlensing survey by the proposed WFIRST Observatory  

Science.gov (United States)

The New Worlds, New Horizons report released by the Astronomy and Astrophysics Decadal Survey Board in 2010 listed the Wide Field Infrared Survey Telescope (WFIRST) as the highest-priority large space mission for the coming decade. This observatory will provide wide-field imaging and slitless spectroscopy at near infrared wavelengths. The scientific goals are to obtain a statistical census of exoplanets using gravitational microlensing, measure the expansion history of and the growth of structure in the Universe by multiple methods, and perform other astronomical surveys to be selected through a guest observer program. A Science Definition Team has been established to assist NASA in the development of a Design Reference Mission that accomplishes this diverse array of science programs with a single observatory. In this paper we present the current WFIRST payload concept and the expected capabilities for planet detection. The observatory, with science goals that are complimentary to the Kepler exoplanet transit mission, is designed to complete the statistical census of planetary systems in the Galaxy, from habitable Earth-mass planets to free floating planets, including analogs to all of the planets in our Solar System except Mercury. The exoplanet microlensing survey will observe for 500 days spanning 5 years. This long temporal baseline will enable the determination of the masses for most detected exoplanets down to 0.1 Earth masses.

Barry, Richard; Kruk, Jeffery; Anderson, Jay; Beaulieu, Jean-Philippe; Bennett, David P.; Catanzarite, Joseph; Cheng, Ed; Gaudi, Scott; Gehrels, Neil; Kane, Stephen; Lunine, Jonathan; Sumi, Takahiro; Tanner, Angelle; Traub, Wesley

2011-09-01

193

Transiting exoplanets from the CoRoT space mission . XIX. CoRoT-23b: a dense hot Jupiter on an eccentric orbit  

DEFF Research Database (Denmark)

We report the detection of CoRoT-23b, a hot Jupiter transiting in front of its host star with a period of 3.6314 ± 0.0001 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite, combined with spectroscopic radial velocity (RV) measurements. A photometric search for possible background eclipsing binaries conducted at CFHT and OGS concluded with a very low risk of false positives. The usual techniques of combining RV and transit data simultaneously were used to derive stellar and planetary parameters. The planet has a mass of Mp = 2.8 ± 0.3 MJup, a radius of Rpl= 1.05 ± 0.13RJup, a density of â?? 3 gâ??cm-3. RV data also clearly reveal a nonzero eccentricity of e = 0.16 ± 0.02. The planet orbits a mature G0 main sequence star of V = 15.5 mag, with a mass Mâ?? = 1.14 ± 0.08 Mâ??, a radius R â?? = 1. 61 ± 0.18 Râ??â?? and quasi-solarabundances. The age of the system is evaluated to be 7 Gyr, not far from the transition to subgiant, in agreement with the rather large stellar radius.The two features of a significant eccentricity of the orbit and of a fairly high density are fairly uncommon for a hot Jupiter. The high density is, however, consistent with a model of contraction of a planet at this mass, given the age of the system. On the other hand, at such an age, circularization is expected to be completed. In fact, we show that for this planetary mass and orbital distance, any initial eccentricity should not totally vanish after 7 Gyr, as long as the tidal quality factor Qp is more than a few 105, a value that is the lower bound of the usually expected range. Even if CoRoT-23bâ?? features a density and an eccentricity that are atypical of a hot Jupiter, it is thus not an enigmatic object.

Rouan, D.; Parviainen, H.

2012-01-01

194

The Applicability of Emerging Quantum Computing Capabilities to Exo-Planet Research  

Science.gov (United States)

In conjunction with the Universities Space Research Association and Google, Inc. NASA Ames has acquired a quantum computing device built by DWAVE Systems with approximately 512 “qubits.” Quantum computers have the feature that their capabilities to find solutions to problems with large numbers of variables scale linearly with the number of variables rather than exponentially with that number. These devices may have significant applicability to detection of exoplanet signals in noisy data. We have therefore explored the application of quantum computing to analyse stellar transiting exoplanet data from NASA’s Kepler Mission. The analysis of the case studies was done using the DWAVE Systems’s BlackBox compiler software emulator, although one dataset was run successfully on the DWAVE Systems’s 512 qubit Vesuvius machine. The approach first extracts a list of candidate transits from the photometric lightcurve of a given Kepler target, and then applies a quantum annealing algorithm to find periodicity matches between subsets of the candidate transit list. We examined twelve case studies and were successful in reproducing the results of the Kepler science pipeline in finding validated exoplanets, and matched the results for a pair of candidate exoplanets. We conclude that the current implementation of the algorithm is not sufficiently challenging to require a quantum computer as opposed to a conventional computer. We are developing more robust algorithms better tailored to the quantum computer and do believe that our approach has the potential to extract exoplanet transits in some cases where a conventional approach would not in Kepler data. Additionally, we believe the new quantum capabilities may have even greater relevance for new exoplanet data sets such as that contemplated for NASA’s Transiting Exoplanet Survey Satellite (TESS) and other astrophysics data sets.

Correll, Randall; Worden, S.

2014-01-01

195

Exoplanets Search in NGC 188 and Several Other Open Clusters  

Science.gov (United States)

As a pilot project in the detection of exoplanets in star clusters using transit measurements, we have made use of the time series CCD photometry survey of the old open cluster NGC 188 obtained by the wide-field observations (one squre segree) of the BATC (Beijng-Arizona-Taiwan-Connecticut) Schmidt telescope at Beijing Astronomical observatory. The main purpose is to assess whether the photometric accuracy of the BATC observations can be used to search for Jupiter-sized exoplanets. As a follow-up study, using the One-meter telescope (LOT) on the Lulin Observatory of National Central University, we will observe NGC 2324, Haffner 6, Haffner 8, NGC 2374, NGC 2420 and NGC 2506 in R-band. The Box-fitting Least Squares (BLS) algorithm will be developed to analyse the possible transit features from the light curves. The preliminary results will be reported.

Hu, J. H.; Ip, W.-H.; Zhang, X. B.

2003-04-01

196

Transiting exoplanets from the CoRoT space mission. XVIII. CoRoT-18b: a massive hot Jupiter on a prograde, nearly aligned orbit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report the detection of CoRoT-18b, a massive hot Jupiter transiting in front of its host star with a period of 1.9000693 ± 0.0000028 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite combined with spectroscopic and photometric ground-based follow-up observations. The planet has a mass M[SUB]p[/SUB] = 3.47 ± 0.38 M[SUB]Jup[/SUB], a radius R[SUB]p[/SUB] = 1.31 ± 0.18 R[SUB]Jup[/SUB], and a density ?[SUB]p[/SUB] = 2.2 ± 0.8 g cm[SUP]-3[/SUP]. It...

2011-01-01

197

Kepler Observations of Three Pre-Launch Exoplanet Candidates: Discovery of Two Eclipsing Binaries and a New Exoplanet  

CERN Document Server

Three transiting exoplanet candidate stars were discovered in a ground-based photometric survey prior to the launch of NASA's {\\it Kepler} mission. {\\it Kepler} observations of them were obtained during Quarter 1 of the {\\it Kepler} mission. All three stars are faint by radial velocity follow-up standards, so we have examined these candidates with regard to eliminating false positives and providing high confidence exoplanet selection. We present a first attempt to exclude false positives for this set of faint stars without high resolution radial velocity analysis. This method of exoplanet confirmation will form a large part of the {\\it Kepler} mission follow-up for Jupiter-sized exoplanet candidates orbiting faint stars. Using the {\\it Kepler} light curves and pixel data, as well as medium resolution reconnaissance spectroscopy and speckle imaging, we find that two of our candidates are binary stars. One consists of a late-F star with an early M companion while the other is a K0 star plus a late M-dwarf/brown...

Howell, Steve B; Sherry, William; von Braun, Kaspar; Ciardi, David R; Bryson, Stephen T; Feldmeier, John J; Horch, Elliott; van Belle, Gerard T

2010-01-01

198

Exoplanet detection capability of the COROT space mission  

Digital Repository Infrastructure Vision for European Research (DRIVER)

COROT will be the first high precision photometric satellite to be launched with the aim of detecting exoplanets by the transit method. In this paper, we present the simulations we have carried out in order to assess the detection capability of COROT. Using the model of stellar population synthesis of the Galaxy developed at Besancon Observatory (Robin & Creze 1986) and a simple cross-correlation technique (Borde et al. 2001), we find that COROT has the capacity to detect nu...

Borde, P.; Rouan, D.; Leger, A.

2003-01-01

199

Transiting exoplanets from the CoRoT space mission. VIII. CoRoT-7b: the first super-Earth with measured radius  

Science.gov (United States)

Aims: We report the discovery of very shallow (? F/F ? 3.4× 10-4), periodic dips in the light curve of an active V = 11.7 G9V star observed by the CoRoT satellite, which we interpret as caused by a transiting companion. We describe the 3-colour CoRoT data and complementary ground-based observations that support the planetary nature of the companion. Methods: We used CoRoT colours information, good angular resolution ground-based photometric observations in- and out- of transit, adaptive optics imaging, near-infrared spectroscopy, and preliminary results from radial velocity measurements, to test the diluted eclipsing binary scenarios. The parameters of the host star were derived from optical spectra, which were then combined with the CoRoT light curve to derive parameters of the companion. Results: We examined all conceivable cases of false positives carefully, and all the tests support the planetary hypothesis. Blends with separation >0.40´´or triple systems are almost excluded with a 8 × 10-4 risk left. We conclude that, inasmuch we have been exhaustive, we have discovered a planetary companion, named CoRoT-7b, for which we derive a period of 0.853 59 ± 3 × 10-5 day and a radius of Rp = 1.68 ± 0.09 R_Earth. Analysis of preliminary radial velocity data yields an upper limit of 21 M_Earth for the companion mass, supporting the finding. Conclusions: CoRoT-7b is very likely the first Super-Earth with a measured radius. This object illustrates what will probably become a common situation with missions such as Kepler, namely the need to establish the planetary origin of transits in the absence of a firm radial velocity detection and mass measurement. The composition of CoRoT-7b remains loosely constrained without a precise mass. A very high surface temperature on its irradiated face, ?1800-2600 K at the substellar point, and a very low one, ?50 K, on its dark face assuming no atmosphere, have been derived. The CoRoT?space mission, launched on 27 December 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA, Germany, and Spain. First CoRoT?data are available to the public from the CoRoT?archive: http://idoc-corot.ias.u-psud.fr. The complementary observations were obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT) which is operated by NRC in Canada, INSU-CNRS in France, and the University of Hawaii; ESO Telescopes at the La Silla and Paranal Observatories under programme ID 081.C-0413(C), DDT 282.C-5015; the IAC80 telescope operated by the Instituto de Astrofísica de Tenerife at the Observatorio del Teide; the Isaac Newton Telescope (INT), operated on the island of La Palma by the Isaac Newton group in the Spanish Observatorio del Roque de Los Muchachos of the Instituto de Astrofisica de Canarias; and at the Anglo-Australian Telescope that have been funded by the Optical Infrared Coordination network (OPTICON), a major international collaboration supported by the Research Infrastructures Programme of the European Commissions Sixth Framework Programme; Radial-velocity observations were obtained with the SOPHIE spectrograph at the 1.93m telescope of Observatoire de Haute Provence, France.

Léger, A.; Rouan, D.; Schneider, J.; Barge, P.; Fridlund, M.; Samuel, B.; Ollivier, M.; Guenther, E.; Deleuil, M.; Deeg, H. J.; Auvergne, M.; Alonso, R.; Aigrain, S.; Alapini, A.; Almenara, J. M.; Baglin, A.; Barbieri, M.; Bruntt, H.; Bordé, P.; Bouchy, F.; Cabrera, J.; Catala, C.; Carone, L.; Carpano, S.; Csizmadia, Sz.; Dvorak, R.; Erikson, A.; Ferraz-Mello, S.; Foing, B.; Fressin, F.; Gandolfi, D.; Gillon, M.; Gondoin, Ph.; Grasset, O.; Guillot, T.; Hatzes, A.; Hébrard, G.; Jorda, L.; Lammer, H.; Llebaria, A.; Loeillet, B.; Mayor, M.; Mazeh, T.; Moutou, C.; Pätzold, M.; Pont, F.; Queloz, D.; Rauer, H.; Renner, S.; Samadi, R.; Shporer, A.; Sotin, Ch.; Tingley, B.; Wuchterl, G.; Adda, M.; Agogu, P.; Appourchaux, T.; Ballans, H.; Baron, P.; Beaufort, T.; Bellenger, R.; Berlin, R.; Bernardi, P.; Blouin, D.; Baudin, F.; Bodin, P.; Boisnard, L.; Boit, L.; Bonneau, F.; Borzeix, S.; Briet, R.; Buey, J.-T.; Butler, B.; Cailleau, D.; Cautain, R.; Chabaud, P.-Y.; Chaintreuil, S.; Chiavassa, F.; Costes, V.; Cuna Parrho, V.; de Oliveira Fialho, F.; Decaudin, M.; Defise, J.-M.; Djalal, S.; Epstein, G.; Exil, G.-E.; Fauré, C.; Fenouillet, T.; Gaboriaud, A.; Gallic, A.; Gamet, P.; Gavalda, P.; Grolleau, E.; Gruneisen, R.; Gueguen, L.; Guis, V.; Guivarc'h, V.; Guterman, P.; Hallouard, D.; Hasiba, J.; Heuripeau, F.; Huntzinger, G.; Hustaix, H.; Imad, C.; Imbert, C.; Johlander, B.; Jouret, M.; Journoud, P.; Karioty, F.; Kerjean, L.; Lafaille, V.; Lafond, L.; Lam-Trong, T.; Landiech, P.; Lapeyrere, V.; Larqué, T.; Laudet, P.; Lautier, N.; Lecann, H.; Lefevre, L.; Leruyet, B.; Levacher, P.; Magnan, A.; Mazy, E.; Mertens, F.; Mesnager, J.-M.; Meunier, J.-C.; Michel, J.-P.; Monjoin, W.; Naudet, D.; Nguyen-Kim, K.; Orcesi, J.-L.; Ottacher, H.; Perez, R.; Peter, G.; Plasson, P.; Plesseria, J.-Y.; Pontet, B.; Pradines, A.; Quentin, C.; Reynaud, J.-L.; Rolland, G.; Rollenhagen, F.; Romagnan, R.; Russ, N.; Schmidt, R.; Schwartz, N.; Sebbag, I.; Sedes, G.; Smit, H.; Steller, M. B.; Sunter, W.; Surace, C.; Tello, M.; Tiphène, D.; Toulouse, P.; Ulmer, B.; Vandermarcq, O.; Vergnault, E.; Vuillemin, A.; Zanatta, P.

2009-10-01

200

Transiting exoplanets from the CoRoT space mission. XXV. CoRoT-27b: a massive and dense planet on a short-period orbit  

Science.gov (United States)

Aims: We report the discovery of a massive and dense transiting planet CoRoT-27b on a 3.58-day orbit around a 4.2 Gyr-old G2 star. The planet candidate was identified from the CoRoT photometry, and was confirmed as a planet with ground-based spectroscopy. Methods: The confirmation of the planet candidate is based on radial velocity observations combined with imaging to rule out blends. The characterisation of the planet and its host star was carried out using a Bayesian approach where all the data (CoRoT photometry, radial velocities, and spectroscopic characterisation of the star) are used jointly. The Bayesian analysis included a study whether the assumption of white normally distributed noise holds for the CoRoT photometry and whether the use of a non-normal noise distribution offers advantages in parameter estimation and model selection. Results: CoRoT-27b has a mass of 10.39 ± 0.55MJup, a radius of 1.01 ± 0.04RJup, a mean density of 12.6-1.67+1.92g cm-3, and an effective temperature of 1500 ± 130 K. The planet orbits around its host star, a 4.2 Gyr-old G2-star with a mass M? = 1.06M? and a radius R? = 1.05R?, on a 0.048 ± 0.007 AU orbit of 3.58 days. The radial velocity observations allow us to exclude highly eccentric orbits, namely, e fractions of 0.11 ± 0.08M? and 0.07 ± 0.06M?, but even solutions void of heavy elements cannot be excluded. We carry out a secondary eclipse search from the CoRoT photometry using a method based on Bayesian model selection, but conclude that the noise level is too high to detect eclipses shallower than 9% of the transit depth. Using a non-normal noise model was shown not to affect the parameter estimation results, but led to significant improvement in the sensitivity of the model selection process. The CoRoT space mission, launched on December 27, 2006, has been developed and is operated by the CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany, and Spain.

Parviainen, H.; Gandolfi, D.; Deleuil, M.; Moutou, C.; Deeg, H. J.; Ferraz-Mello, S.; Samuel, B.; Csizmadia, Sz.; Pasternacki, T.; Wuchterl, G.; Havel, M.; Fridlund, M.; Angus, R.; Tingley, B.; Grziwa, S.; Korth, J.; Aigrain, S.; Almenara, J. M.; Alonso, R.; Baglin, A.; Barros, S. C. C.; Bordé, P.; Bouchy, F.; Cabrera, J.; Díaz, R. F.; Dvorak, R.; Erikson, A.; Guillot, T.; Hatzes, A.; Hébrard, G.; Mazeh, T.; Montagnier, G.; Ofir, A.; Ollivier, M.; Pätzold, M.; Rauer, H.; Rouan, D.; Santerne, A.; Schneider, J.

2014-02-01

 
 
 
 
201

Transiting exoplanets from the CoRoT space mission XXV. CoRoT-27b: a massive and dense planet on a short-period orbit  

CERN Multimedia

We report the discovery of a massive and dense transiting planet CoRoT-27b on a 3.58 day orbit around a 4.2 Gyr-old G2~star. The planet candidate was identified from the CoRoT photometry, and was confirmed as a planet with ground-based spectroscopy. The confirmation of the planet candidate is based on radial velocity observations combined with imaging to rule out blends. The characterisation of the planet and its host star is carried out using a Bayesian approach where all the data (CoRoT photometry, radial velocities, and spectroscopic characterisation of the star) are used jointly. The Bayesian analysis includes a study whether the assumption of white normally distributed noise holds for the CoRoT photometry, and whether the use of a non-normal noise distribution offers advantages in parameter estimation and model selection. CoRoT-27b has a mass of $10.39 \\pm 0.55$ $\\mathrm{M}_{\\rm Jup}$, a radius of $1.01 \\pm 0.04$ $\\mathrm{R}_{\\rm Jup}$, a mean density of $12.6_{-1.67}^{+1.92}$ $\\mathrm{g\\,cm^{-3}}$, and ...

Parviainen, H; Deleuil, M; Moutou, C; Deeg, H J; Ferraz-Mello, S; Samuel, B; Csizmadia, Sz; Pasternacki, T; Wuchterl, G; Havel, M; Fridlund, M; Agnus, R; Tingley, B; Aigrain, S; Almenara, J M; Alonso, R; Baglin, A; Barros, S; Bordé, A S P; Bouchy, F; Cabrera, J; Díaz, R; Dvorak, R; Erikson, A; Guillot, T; Hatzes, A; Hébrard, G; Mazeh, T; Montagnier, G; Ofir, A; Ollivier, M; Pätzold, M; Rauer, H; Rouan, D; Santerne, A; Schneider, J

2014-01-01

202

Analytic Description of the Rossiter-McLaughlin Effect for Transiting Exoplanets: Cross-Correlation Method and Comparison with Simulated Data  

CERN Multimedia

We obtain analytical expressions for the velocity anomaly due to the Rossiter-McLaughlin effect, for the case when the anomalous radial velocity is obtained by cross-correlation with a stellar template spectrum. In the limit of vanishing width of the stellar absorption lines, our result reduces to the formula derived by Ohta et al. (2005), which is based on the first moment of distorted stellar lines. Our new formula contains a term dependent on the stellar linewidth, which becomes important when rotational line broadening is appreciable. We generate mock transit spectra for the exoplanetary systems HD17156 and TrES-4 following the procedure of Winn et al. (2005), and find that the new formula is in better agreement with the velocity anomaly extracted from the mock data. Thus, our result provides a more reliable analytical description of the velocity anomaly due to the Rossiter-McLaughlin effect, and explains the previously observed dependence of the velocity anomaly on the stellar rotation velocity.

Hirano, Teruyuki; Taruya, Atsushi; Narita, Norio; Sato, Bun'ei; Johnson, John Asher; Winn, Joshua N

2009-01-01

203

Subaru SEEDS Survey of Exoplanets and Disks  

Science.gov (United States)

The Strategic Exploration of Exoplanets and Disks at Subaru (SEEDS) is the first strategic observing program (SSOPs) awarded by the National Astronomical Observatory of Japan (NAOJ). SEEDS targets a broad sample of stars that span a wide range of masses and ages to explore the formation and evolution of planetary systems. This survey has been awarded 120 nights over five years time to observe nearly 500 stars. Currently in the second year, SEEDS has already produced exciting new results for the protoplanetary disk AB Aur, transitional disk LkCa15, and nearby companion to GJ 758. We present the survey architecture, performance, recent results, and the projected sample. Finally, we will discuss planned upgrades to the high contrast instrumentation at the Subaru Telescope

McElwain, Michael W.

2012-01-01

204

Broadband Eclipse Spectra of Exoplanets are Featureless  

CERN Document Server

Spectral retrieval methods leverage features in emission spectra to constrain the atmospheric composition and structure of transiting exoplanets. Most of the observed emission spectra consist of broadband photometric observations at a small number of wavelengths. We compare the Bayesian Information Criterion (BIC) of blackbody fits and spectral retrieval fits for all planets with eclipse measurements in multiple thermal wavebands, typically hot Jupiters with 2-4 observations. If the published error bars are taken at face value, then eight planets are significantly better fit by a spectral model than by a blackbody. In this under-constrained regime, however, photometric uncertainties directly impact one's ability to constrain atmospheric properties. By considering the handful of planets for which eclipse measurements have been repeated and/or reanalyzed, we obtain an empirical estimate of systematic uncertainties for broadband eclipse depths obtained with the Spitzer Space Telescope: sigma_sys = 5E-4. When thi...

Hansen, C J; Cowan, N B

2014-01-01

205

Towards consistent mapping of distant worlds: secondary-eclipse scanning of the exoplanet HD 189733b  

Science.gov (United States)

Context. Mapping distant worlds is the next frontier for exoplanet infrared (IR) photometry studies. Ultimately, constraining spatial and temporal properties of an exoplanet atmosphere (e.g., its temperature) will provide further insight into its physics. For tidally-locked hot Jupiters that transit and are eclipsed by their host star, the first steps are now possible. Aims: Our aim is to constrain an exoplanet's (1) shape, (2) brightness distribution (BD) and (3) system parameters from its phase curve and eclipse measurements. In particular, we rely on the secondary-eclipse scanning which is obtained while an exoplanet is gradually masked by its host star. Methods: We use archived Spitzer/IRAC 8-?m data of HD 189733 (six transits, eight secondary eclipses, and a phase curve) in a global Markov chain Monte Carlo (MCMC) procedure for mitigating systematics. We also include HD 189733's out-of-transit radial velocity (RV) measurements to assess their incidence on the inferences obtained solely from the photometry. Results: We find a 6? deviation from the expected occultation of a uniformly-bright disk. This deviation emerges mainly from a large-scale hot spot in HD 189733b's atmosphere, not from HD 189733b's shape. We indicate that the correlation of the exoplanet orbital eccentricity, e, and BD ("uniform time offset") does also depend on the stellar density, ??, and the exoplanet impact parameter, b ("e-b-??-BD correlation"). For HD 189733b, we find that relaxing the eccentricity constraint and using more complex BDs lead to lower stellar/planetary densities and a more localized and latitudinally-shifted hot spot. We, therefore, show that the light curve of an exoplanet does not constrain uniquely its brightness peak localization. Finally, we obtain an improved constraint on the upper limit of HD 189733b's orbital eccentricity, e ? 0.011 (95% confidence), when including HD 189733's RV measurements. Conclusions: Reanalysis of archived HD 189733's data constrains HD 189733b's shape and BD at 8 ?m. Our study provides new insights into the analysis of exoplanet light curves and a proper framework for future eclipse-scanning observations. In particular, observations of the same exoplanet at different wavelengths could improve the constraints on HD 189733's system parameters while ultimately yielding a large-scale time-dependent 3D map of HD 189733b's atmosphere. Finally, we discuss the perspective of extending our method to observations in the visible (e.g., Kepler data), in particular to better understand exoplanet albedos. Movies are available in electronic form at http://www.aanda.org

de Wit, J.; Gillon, M.; Demory, B.-O.; Seager, S.

2012-12-01

206

Three Distinct Exoplanet Regimes Inferred From Host Star Metallicities  

Science.gov (United States)

The occurrence rate of exoplanets smaller than 4 Earth radii (RE) in short orbits is ~50%. Despite their sheer abundance, the compositions of planets populating this regime are largely unknown. The available evidence suggests the existence of a compositional range, from small high-density rocky planets to low-density planets consisting of rocky cores surrounded by thick H/He gas envelopes. Understanding the transition from the gaseous planets to Earth-like rocky worlds is important to estimate the number of potentially habitable planets in our Galaxy and provide constraints on planet formation theories. Here, we report the abundances of heavy elements (metallicities) of over 400 stars hosting 600 exoplanet candidates discovered by the Kepler Mission and find that the exoplanets can be categorized into three populations defined by statistically distinct 4.5?) metallicity regions. We interpret these regions as reflecting the formation regimes of terrestrial-like planets (RP < 1.7 RE), gas-dwarf planets with rocky cores and H/He envelopes (1.7 < RP < 3.9 RE) and ice/gas-giant planets (RP > 3.9 RE). These transitions resonate well with those inferred from dynamical mass estimates, implying that host-star metallicity - a proxy for the initial solid inventory of the protoplanetary disk - is a key ingredient regulating the structure of planetary systems.

Buchhave, Lars A.; Bizzarro, Martin; Latham, David W.; Sasselov, Dimitar D.

2014-06-01

207

EChOSim: The Exoplanet Characterisation Observatory software simulator  

CERN Document Server

EChOSim is the end-to-end time-domain simulator of the Exoplanet Characterisation Observatory (EChO) space mission. EChOSim has been developed to assess the capability EChO has to detect and characterize the atmospheres of transiting exoplanets, and through this revolutionize the knowledge we have of the Milky Way and of our place in the Galaxy. Here we discuss the details of the EChOSim implementation and describe the models used to represent the instrument and to simulate the detection. Software simulators have assumed a central role in the design of new instrumentation and in assessing the level of systematics affecting the measurements of existing experiments. Thanks to its high modularity, EChOSim can simulate basic aspects of several existing and proposed spectrometers for exoplanet transits, including instruments on the Hubble Space Telescope and Spitzer, or ground-based and balloon borne experiments. A discussion of different uses of EChOSim is given, including examples of simulations performed to ass...

Pascale, E; MacTavish, C J; Papageorgiou, A; Amaral-Rogers, A; Varley, R; de Foresto, V Coudé; Griffin, M J; Ollivier, M; Sarkar, S; Spencer, L; Swinyard, B M; Tessenyi, M; Tinetti, G

2014-01-01

208

The SPICA coronagraphic instrument (SCI) for the study of exoplanets  

CERN Document Server

We present the SPICA Coronagraphic Instrument (SCI), which has been designed for a concentrated study of extra-solar planets (exoplanets). SPICA mission provides us with a unique opportunity to make high contrast observations because of its large telescope aperture, the simple pupil shape, and the capability for making infrared observations from space. The primary objectives for the SCI are the direct coronagraphic detection and spectroscopy of Jovian exoplanets in infrared, while the monitoring of transiting planets is another important target. The specification and an overview of the design of the instrument are shown. In the SCI, coronagraphic and non-coronagraphic modes are applicable for both an imaging and a spectroscopy. The core wavelength range and the goal contrast of the coronagraphic mode are 3.5--27$\\mu$m, and 10$^{-6}$, respectively. Two complemental designs of binary shaped pupil mask coronagraph are presented. The SCI has capability of simultaneous observations of one target using two channels...

Enya, K; Haze, K; Aono, K; Nakagawa, T; Matsuhara, H; Kataza, H; Wada, T; Kawada, M; Fujiwara, K; Mita, M; Takeuchi, S; Komatsu, K; Sakai, S; Uchida, H; Mitani, S; Yamawaki, T; Miyata, T; Sako, S; Nakamura, T; Asano, K; Yamashita, T; Narita, N; Matsuo, T; Tamura, M; Nishikawa, J; Kokubo, E; Hayano, Y; Oya, S; Fukagawa, M; Shibai, H; Baba, N; Murakami, N; Itoh, Y; Honda, M; Okamoto, B; Ida, S; Takami, M; Abe, L; Guyon, O; Bierden, P; Yamamuro, T; 10.1016/j.asr.2011.03.010

2011-01-01

209

ASTEP: Towards the detection and characterization of exoplanets from Dome C  

Directory of Open Access Journals (Sweden)

Full Text Available The ASTEP project (Antarctic Search for Transiting ExoPlanets, aims at testing the quality of the Dome C site in Antarctica for photometry in the visible, as well as detecting and characterizing transiting exoplanets. A dedicated telescope, ASTEP400, has been developped and installed at Concordia. The ?rst campaign took place during the winter 2010, and the telescope functionned nominally during all the winter. A ?rst analysis of the data leads to a precision of 189 and 205 ppm for WASP-19 and WASP-18 respectively, for continuous observations during 1 month. This shows that extremely high precision photometry is achievable from Dome C.

Rauer H.

2011-02-01

210

The Brown Dwarf-Exoplanet Connection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Brown dwarfs are commonly regarded as easily-observed templates for exoplanet studies, with comparable masses, physical sizes and atmospheric properties. There is indeed considerable overlap in the photospheric temperatures of the coldest brown dwarfs (spectral classes L and T) and the hottest exoplanets. However, the properties and processes associated with brown dwarf and exoplanet atmospheres can differ significantly in detail; photospheric gas pressures, elemental abunda...

Burgasser, Adam J.

2009-01-01

211

High-temperature measurements of VUV-absorption cross sections of CO2 and their application to exoplanets  

CERN Document Server

UV absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar system. Transiting exoplanets whose atmospheres can now be studied by transit spectroscopy receive extremely strong UV fluxes and have typical temperatures ranging from 400 to 2500 K. At these temperatures, UV photolysis cross section data are severely lacking. Aims. Our goal is to provide high-temperature absorption cross sections and their temperature dependency for important atmospheric compounds. This study is dedicated to CO2, which is observed and photodissociated in exoplanet atmospheres. We also investigate the influence of these new data on the photochemistry of some exoplanets. We performed these measurements for the 115 - 200 nm range at 300, 410, 480, and 550 K. In the 195 - 230 nm range, we worked at seven temperatures between 465 and 800 K. We implemented the mea...

Venot, Olivia; Bénilan, Yves; Gazeau, Marie-Claire; Hébrard, Eric; Larcher, Gwenaelle; Schwell, Martin; Dobrijevic, Michel; Selsis, Franck

2013-01-01

212

Cloud Base Signature in Transmission Spectra of Exoplanet Atmospheres  

Science.gov (United States)

We present an analytical model for the transmission spectrum of a transiting exoplanet, showing that a cloud base can produce an observable inflection point in the spectrum. The wavelength and magnitude of the inflection can be used to break the degeneracy between the atmospheric pressure and the abundance of the main cloud material, however, the abundance still depends on cloud particle size. An observed inflection also provides a specific point on the atmospheric P-T profile, giving us a "thermometer" to directly validate or rule out postulated cloud species. We apply the model to the transit spectrum of HD 189733b.

Vahidinia, Sanaz; Cuzzi, Jeffrey N.; Marley, Mark; Fortney, Jonathan

2014-07-01

213

Cloud Base Signature in Transmission Spectra of Exoplanet Atmospheres  

CERN Document Server

We present an analytical model for the transmission spectrum of a transiting exoplanet, showing that a cloud base can produce an observable inflection point in the spectrum. The wavelength and magnitude of the inflection can be used to break the degeneracy between the atmospheric pressure and the abundance of the main cloud material, however, the abundance still depends on cloud particle size. An observed inflection also provides a specific point on the atmospheric P-T profile, giving us a "thermometer" to directly validate or rule out postulated cloud species. We apply the model to the transit spectrum of HD 189733b.

Vahidinia, Sanaz; Marley, Mark; Fortney, Jonathan

2014-01-01

214

The TERMS Project: More Than Just Transit Exclusion  

Science.gov (United States)

The field of exoplanets has rapidly expanded from the exclusivity of exoplanet detection to include exoplanet characterization. Even so, studies of internal structure and atmospheres have been largely restricted to the low-periastron distance regime due to the bias inherent in the geometric transit probability. Monitoring known radial velocity planets at predicted transit times is a proven method of detecting transits, and presents an avenue through which to explore the mass-radius relationship of exoplanets at long periods around bright host stars. Here we present new results from the Transit Ephemeris Refinement and Monitoring Survey (TERMS) which provide greater insight into the dynamics of several interesting exosystems.

Kane, Stephen R.; Transit Ephemeris Refinement and Monitoring Survey (TERMS)

2012-01-01

215

Atmospheric Circulation of Terrestrial Exoplanets  

CERN Multimedia

The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical and dynamical conditions, only a small fraction of which have yet been explored in detail. Our approach is to lay out the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined--and show how they can provide a foundation for understanding the atmospheric behavior of these worlds. We first survey basic atmospheric dynamics, including the role of geostrophy, baroclinic instabilities, and jets in the strongly rotating regime (the "extratropics") and the role of the Hadle...

Showman, Adam P; Merlis, Timothy M; Kaspi, Yohai

2013-01-01

216

Abundances in stars with exoplanets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Extensive spectroscopic studies of stars with and without planets have concluded that stars hosting planets are significantly more metal-rich than those without planets. More subtle trends of different chemical elements begin to appear as the number of detected extrasolar planetary systems continues to grow. I review our current knowledge concerning the observed abundance trends of various chemical elements in stars with exoplanets and their possible implications.

Israelian, Garik

2003-01-01

217

The Exoplanet Handbook  

Science.gov (United States)

1. Introduction; 2. Radial velocities; 3. Astrometry; 4. Timing; 5. Microlensing; 6. Transits; 7. Imaging; 8. Host stars; 9. Brown dwarfs and free-floating planets; 10. Formation and evolution; 11. Interiors and atmospheres; 12. The Solar System; Appendixes; References; Index.

Perryman, Michael

2014-01-01

218

A Research-Informed Approach to Teaching About Exoplanet Detection in STEM Classrooms  

Science.gov (United States)

JPL’s NASA Exoplanet Exploration Program’s (ExEP) Public Engagement Program, in collaboration with the Center for Astronomy Education (CAE), is engaged in a research and curriculum development program to bring the science of exoplanet detection into STEM classrooms. In recent years, there has been a significant increase in the number of astronomers pursuing research related to exoplanets, along with a significant increase in interest amongst students and the general public regarding the topic of exoplanets. CAE has previously developed a curriculum unit (including Think-Pair-Share questions and a Lecture-Tutorial) to help students develop a deeper understanding of the Doppler method for detecting extrasolar planets. To date, there is a nearly nonexistent research base on students’ conceptual and reasoning difficulties related to the science of the transit and gravitational microlensing methods for detecting extrasolar planets. Appropriate for physical science classrooms from middle school to the introductory college level, the learner-centered active engagement activities we are developing are going through an iterative research and assessment process to ensure that they enable students to achieve increased conceptual understandings and reasoning skills in these areas. In this talk, we will report on our development process for two new Lecture-Tutorials that help students learn about the transit and gravitational microlensing methods for finding exoplanets.

Brissenden, Gina; Wallace, C. S.; Prather, E. E.; Traub, W. A.; Greene, W. M.; Biferno, A. A.

2014-01-01

219

Constraining Exoplanet Mass from Transmission Spectroscopy  

Science.gov (United States)

Determination of an exoplanet’s mass is a key to understanding its basic properties, including its potential for supporting life. To date, mass constraints for exoplanets are predominantly based on radial velocity (RV) measurements, which are not suited for planets with low masses, large semimajor axes, or those orbiting faint or active stars. Here, we present a method to extract an exoplanet’s mass solely from its transmission spectrum. We find good agreement between the mass retrieved for the hot Jupiter HD 189733b from transmission spectroscopy with that from RV measurements. Our method will be able to retrieve the masses of Earth-sized and super-Earth planets using data from future space telescopes that were initially designed for atmospheric characterization.

de Wit, Julien; Seager, Sara

2013-12-01

220

Signals of exomoons in averaged light curves of exoplanets  

CERN Document Server

The increasing number of transiting exoplanets sparked a significant interest in discovering their moons. Most of the methods in the literature utilize timing analysis of the raw light curves. Here we propose a new approach for the direct detection of a moon in the transit light curves via the so called Scatter Peak. The essence of the method is the valuation of the local scatter in the folded light curves of many transits. We test the ability of this method with different simulations: Kepler "short cadence", Kepler "long cadence", ground-based millimagnitude photometry with 3-min cadence, and the expected data quality of the planned ESA mission of PLATO. The method requires ~100 transit observations, therefore applicable for moons of 10-20 day period planets, assuming 3-4-5 year long observing campaigns with space observatories. The success rate for finding a 1 R_Earth moon around a 1 R_Jupiter exoplanet turned out to be quite promising even for the simulated ground-based observations, while the detection li...

Simon, A E; Kiss, L L; Szatmáry, K

2011-01-01

 
 
 
 
221

Transiting exoplanets from the CoRoT space mission IX. CoRoT-6b: a transiting `hot Jupiter' planet in an 8.9d orbit around a low-metallicity star  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The CoRoT satellite exoplanetary team announces its sixth transiting planet in this paper. We describe and discuss the satellite observations as well as the complementary ground-based observations - photometric and spectroscopic - carried out to assess the planetary nature of the object and determine its specific physical parameters. The discovery reported here is a `hot Jupiter' planet in an 8.9d orbit, 18 stellar radii, or 0.08 AU, away from its primary star, which is a solar-type star (F9V...

2010-01-01

222

A search for transit timing variation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Photometric follow-ups of transiting exoplanets (TEPs) may lead to discoveries of additional, less massive bodies in extrasolar systems. This is possible by detecting and then analysing variations in transit timing of transiting exoplanets. In 2009 we launched an international observing campaign, the aim of which is to detect and characterise signals of transit timing variation (TTV) in selected TEPs. The programme is realised by collecting data from 0.6-2.2-m telescopes spread worldwide at d...

Maciejewski G.; Neuhäuser R.; Raetz St.; Errmann R.; Kramm U.; Schmidt T.O.B.

2011-01-01

223

The Exoplanet Eccentricity Distribution from Kepler Planet Candidates  

CERN Multimedia

The eccentricity distribution of exoplanets is known from radial velocity surveys to be divergent from circular orbits beyond 0.1 AU. This is particularly the case for large planets where the radial velocity technique is most sensitive. The eccentricity of planetary orbits can have a large effect on the transit probability and subsequently the planet yield of transit surveys. The Kepler mission is the first transit survey that probes deep enough into period-space to allow this effect to be seen via the variation in transit durations. We use the Kepler planet candidates to show that the eccentricity distribution matches that found from radial velocity surveys to a high degree of confidence. We further show that the mean eccentricity of the Kepler candidates decreases with decreasing planet size indicating that smaller planets are preferentially found in low-eccentricity orbits.

Kane, Stephen R; Gelino, Dawn M; von Braun, Kaspar

2012-01-01

224

Resource Letter Exo-1: Exoplanets  

CERN Document Server

This Resource Letter gives an introduction to the main topics in exoplanet research. It is intended to serve as a guide to the field for upper-division undergraduate and graduate students, both theoretical and experimental, and for workers in other fields of physics and astronomy who wish learn about this new discipline. Topics include historical background, detection methods, host star properties, theories of planet formation and evolution, their interiors and atmospheres, their relationship to the formation and evolution of our own solar system, and issues of life and habitability.

Perryman, Michael

2013-01-01

225

Resource Letter Exo-1: Exoplanets  

Science.gov (United States)

This Resource Letter gives an introduction to the main topics in exoplanet research. It is intended to serve as a guide to the field for upper-division undergraduate and graduate students, both theoretical and experimental, and for workers in other fields of physics and astronomy who wish learn about this new discipline. Topics include historical background, detection methods, host star properties, theories of planet formation and evolution, their interiors and atmospheres, their relationship to the formation and evolution of our own solar system, and issues of life and habitability.

Perryman, Michael

2014-06-01

226

From spectra to atmospheres: solving the underconstrained retrieval problem for exoplanets  

Science.gov (United States)

Spectroscopic observations of transiting exoplanets have provided the first indications of their atmospheric structure and composition. Optimal estimation retrievals have been successfully applied to solar system planets to determine the temperature, composition and aerosol properties of their atmospheres, and have recently been applied to exoplanets. We show the effectiveness of the technique when combined with simulated observations from the proposed space telescope EChO, and also discuss the difficulty of constraining a complex system with sparse data and large uncertainties, using the super-Earth GJ 1214b as an example.

Barstow, Joanna K.; Aigrain, Suzanne; Irwin, Patrick G. J.; Bowles, Neil; Fletcher, Leigh N.; Lee, Jae-Min

2014-01-01

227

A Relation between Mass and Radius for 59 Exoplanets Smaller than 4 Earth Radii  

Science.gov (United States)

We study the masses and radii of the 59 known exoplanets smaller than 4 Earth radii. We find a linear relation of the form M ? 3R, in units of Earth masses and radii. The RMS of planet masses is 3.8 Earth masses, and our best fit has reduced ?2 = 3.4, indicating a large diversity in planet compositions among small planets. Wu & Lithwick (2013), who also find M ? 3R for a different sample of small exoplanets characterized primarily with transit timing variations, note that the linear scaling is consistent with a constant escape velocity.

Weiss, Lauren M.; Marcy, G. W.

2014-01-01

228

Achieving high-precision pointing on ExoplanetSat: Initial feasibility analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

ExoplanetSat is a proposed three-unit CubeSat designed to detect down to Earth-sized exoplanets in an orbit out to the habitable zone of Sun-like stars via the transit method. To achieve the required photometric precision to make these measurements, the target star must remain within the same fraction of a pixel, which is equivalent to controlling the pointing of the satellite to the arcsecond level. The satellite will use a two-stage control system: coarse control will be performed by a set ...

2010-01-01

229

New Exoplanet Surveys in the Canadian High Arctic at 80 Degrees North  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Observations from near the Eureka station on Ellesmere Island, in the Canadian High Arctic at 80 degrees North, benefit from 24-hour darkness combined with dark skies and long cloud-free periods during the winter. Our first astronomical surveys conducted at the site are aimed at transiting exoplanets; compared to mid-latitude sites, the continuous darkness during the Arctic winter greatly improves the survey's detection efficiency for longer-period transiting planets. We det...

Law, Nicholas M.; Sivanandam, Suresh; Murowinski, Richard; Carlberg, Raymond; Ngan, Wayne; Salbi, Pegah; Ahmadi, Aida; Steinbring, Eric; Halman, Mark; Graham, James

2012-01-01

230

Non-Keplerian Dynamics of Exoplanets  

Science.gov (United States)

Exoplanets are often found with short periods or high eccentricities, and multiple-planet systems are often in resonance. They require dynamical theories that describe more extreme motions than those of the relatively placid planetary orbits of the solar system. We describe the most important dynamical processes in fully formed planetary systems and how they are modeled. Such methods have been applied to detect the evolution of exoplanet orbits in action and to infer dramatic histories from the dynamical properties of planetary systems.

Fabrycky, D. C.

231

Balloon Exoplanet Nulling Interferometer (BENI)  

Science.gov (United States)

We evaluate the feasibility of using a balloon-borne nulling interferometer to detect and characterize exosolar planets and debris disks. The existing instrument consists of a 3-telescope Fizeau imaging interferometer with 3 fast steering mirrors and 3 delay lines operating at 800 Hz for closed-loop control of wavefront errors and fine pointing. A compact visible nulling interferometer is under development which when coupled to the imaging interferometer would in-principle allow deep suppression of starlight. We have conducted atmospheric simulations of the environment above 100,000 feet and believe balloons are a feasible path forward towards detection and characterization of a limited set of exoplanets and their debris disks. Herein we will discuss the BENI instrument, the balloon environment and the feasibility of such as mission.

Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Ford, Holland; Petro, Larry; Herman, Jay; Rinehart, Stephen; Carpenter, Kenneth; Marzouk, Joe

2009-01-01

232

Exoplanets from CoRoT to PLATO  

Science.gov (United States)

ABSTRACT The first mission designed specifically for exo-planetary discovery - CoRoT - has been launched more than one year ago and the first results are being published. The mission - planned and executed by the French space agency CNES, with participation of the European Space Agency, ESA, as well as national contributions from Austria, Belgium, Brazil, Germany and Spain has dual objectives. It is searching for exoplanets, significantly smaller than so far discovered, and it is doing unprecedented precision asteroseismological measurements. In this paper we give a status report on the results of CoRoT, as well as putting the results into the context of other space (e.g. MOST & Spitzer), as well as ground based (radial velocity, microlensing, transit work) results. Partly as a consequence of the success of CoRoT, and thus the building of a European exoplanetary community, research into exo-planets is now an integral part of the European Space Agency's Cosmic Vision Plan. One of the first three candidates for a mission is PLATO - a project that for the first time integrates asteroseismology and exoplanetary transits by observing the same objects. Planned for a flight in 2017 (and a 6 year mission life time) it is currently being studied industrially in Europe. This paper give some basic information about this mission.

Fridlund, M.

2008-09-01

233

Direct detection and spectral characterization of outer exoplanets with the SPICA coronagraph instrument (SCI)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The SPICA coronagraph instrument (SCI) provides high-contrast imaging and moderate resolution (R < 200) spectroscopy at the wavelength range from 3.5 to 27 \\mu m. Based on the planet evolutional model calculated by Burrows et al. (2003), SCI will search for gas giant planets down to one Jupiter mass around nearby young (1 Gyr) stars and two Jupiter masses around nearby old (5 Gyr) stars. SCI also allows to characterizing those planets of less than 1 Gyr by spectroscopic obse...

Matsuo, Taro; Fukagawa, Misato; Kotani, Takayuki; Itoh, Yoichi; Tamura, Motohide; Nakagawa, Takao; Enya, Keigo; Team, The Sci

2011-01-01

234

OPTICAL PHASE CURVES OF KEPLER EXOPLANETS  

Energy Technology Data Exchange (ETDEWEB)

We conducted a comprehensive search for optical phase variations of all close-in (a/R{sub *} < 10) planet candidates in 15 quarters of Kepler space telescope data. After correcting for systematics, we found eight systems that show secondary eclipses as well as phase variations. Of these, five (Kepler-5, Kepler-6, Kepler-8, KOI-64, and KOI-2133) are new and three (TrES-2, HAT-P-7, and KOI-13) have published phase curves, albeit with many fewer observations. We model the full phase curve of each planet candidate, including the primary and secondary transits, and derive their albedos, dayside and nightside temperatures, ellipsoidal variations, and Doppler beaming. We find that KOI-64 and KOI-2133 have nightside temperatures well above their equilibrium values (while KOI-2133 also has an albedo, >1), so we conclude that they are likely to be self-luminous objects rather than planets. The other six candidates have characteristics consistent with their being planets with low geometric albedos (<0.3). For TrES-2 and KOI-13, the Kepler bandpass appears to probe atmospheric layers hotter than the planet's equilibrium temperature. For KOI-13, we detect a never-before-seen third cosine harmonic with an amplitude of 6.7 {+-} 0.3 ppm and a phase shift of -1.1 {+-} 0.1 rad in the phase curve residual, possibly due to its spin-orbit misalignment. We report derived planetary parameters for all six planets, including masses from ellipsoidal variations and Doppler beaming, and compare our results to published values when available. Our results nearly double the number of Kepler exoplanets with measured phase curve variations, thus providing valuable constraints on the properties of hot Jupiters.

Esteves, Lisa J.; De Mooij, Ernst J. W.; Jayawardhana, Ray, E-mail: esteves@astro.utoronto.ca, E-mail: demooij@astro.utoronto.ca, E-mail: rayjay@astro.utoronto.ca [Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada)

2013-07-20

235

Atmospheric mass-loss and evolution of short-period exoplanets: the examples of CoRoT-7b and Kepler-10b  

Science.gov (United States)

Short-period exoplanets potentially lose envelope masses during their evolution because of atmospheric escape caused by the intense X-ray and extreme UV (XUV) radiation from their host stars. We develop a combined model of atmospheric mass-loss calculation and thermal evolution calculation of a planet to simulate its evolution and explore the dependences on the formation history of the planet. Thermal atmospheric escape as well as the Roche lobe overflow contributes to mass-loss. The maximum initial planetary model mass depends primarily on the assumed evolution model of the stellar XUV luminosity. We adapt the model to CoRoT-7b and Kepler-10b to explore the evolution of both planets and the maximum initial mass of these planets. We take the recent X-ray observation of CoRoT-7 into account and explore the effect of different XUV evolution models on the planetary initial mass. Our calculations indicate that both hot super-Earths could be remnants of Jupiter-mass gas planets.

Kurokawa, H.; Kaltenegger, L.

2013-08-01

236

Do have nanosatellites a role in detecting exoplanets?  

CERN Document Server

In December 2012, Austria will launch its first two satellites: UniBRITE and BRITE-Austria. This is the first pair of three, forming a network called BRITE-Constellation. The other pairs being contributed by Canada and Poland. The primary goal of BRITE-Constellation is the exploration of short term intensity variations of bright stars (V>6 mag) for a few years. For each satellite pair, one will employ a blue filter and the other a red filter. With the discovery of the first exoplanet in 1992, more than 800 have been detected since. The high-precision photometry from the BRITE instrument will enable a transit search for exoplanets around bright stars. To estimate the capability of BRITE to detect planets, we include in our calculations technical constraints, such as photometric noise levels for stars accessible by BRITE, the duty cycle and duration of observations. The most important parameter is the fraction of stars harboring a planet. Our simulation is based on 2695 stars distributed over the entire sky. Ke...

Weiss, Werner W; Rowe, Jason

2012-01-01

237

A Temperature and Abundance Retrieval Method for Exoplanet Atmospheres  

CERN Multimedia

We present a new method to retrieve molecular abundances and temperature profiles from exoplanet atmosphere photometry and spectroscopy. We run millions of 1D atmosphere models in order to cover the large range of allowed parameter space, and present error contours in the atmospheric properties, given the data. In order to run such a large number of models, we have developed a parametric pressure-temperature (P-T) profile coupled with line-by-line radiative transfer, hydrostatic equilibrium, and energy balance, along with prescriptions for non-equilibrium molecular composition and energy redistribution. We apply our temperature and abundance retrieval method to the atmospheres of two transiting exoplanets, HD 189733b and HD 209458b, which have the best available Spitzer and HST observations. For HD 189733b, we find efficient day-night redistribution of energy in the atmosphere, and molecular abundance constraints confirming the presence of H2O, CO, CH4, and CO2. For HD 209458b, we confirm and constrain the da...

Madhusudhan, N

2009-01-01

238

Detection and initial characterisation of an exoplanet atmosphere with small aperture telescopes  

Science.gov (United States)

In the recent years atmospheres of exoplanets have been studied with space-based telescopes like the HST or large aperture ground-based telescopes like the Gran Telescopio Canarias. But as the number of suitable exoplanets is rising, comparative studies of atmospheres with a statistically meaningful amount of targets will follow, for which the observational time with large telescopes is limited and expensive. Our aim is to investigate whether it is possible to detect and initially characterise the atmosphere of an exoplanet with small aperture telescopes using chromatic variations in transit depths. We collected multi-color transits in the years 2011 to 2013 using the robotic 1.2m-telescope STELLA on Tenerife as well as the Nordic Optical Telescope and the 70cm-telescope at the Leibniz Institute for Astrophysics Potsdam. The highly inflated Hot Jupiter HAT-P-32 b was chosen as target for our pilot study for its favorable large atmospheric scale height and therefore enhanced atmospheric detectability. Models of the atmospheric spectra of HAT-P-32 b indicate that the STELLA-data can be used to distinguish between a dusty and a cloud-free atmosphere using the gradient in transit depth of the observations in the blue band and in the visible band. Here we want to present our project together with the first results of the transit depth analysis.

Bernt, I.; Müller, M.; Strassmeier, K. G.; Granzer, T.

2013-09-01

239

Generation of an optimal target list for the Exoplanet Characterisation Observatory (EChO)  

CERN Document Server

The Exoplanet Characterisation Observatory EChO is a space mission concept studied by the European Space Agency in the context of the M3 selection process. Through direct measurement of the atmospheric chemical composition of hundreds of exoplanets, EChO would address fundamental questions such as: What are exoplanets made of? How do planets form and evolve? What is the origin of exoplanet diversity? More specifically, EChO is a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planetary sample within its four to six year mission lifetime. In this paper we use the end-to-end instrument simulator EChOSim to model the currently discovered targets, to gauge which targets are observable and assess the EChO performances obtainable for each observing tier and time. We show that EChO would be capable of observing a large and diverse sample of planets even if it were launched today, and the wealth of optimal targets for EChO expected to be discovered ...

Varley, Ryan; Pascale, Enzo; Tessenyi, Marcell; Hollis, Morgan; Morales, Juan Carlos; Tinetti, Giovanna; Swinyard, Bruce; Deroo, Pieter; Ollivier, Marc; Micela, Giusi

2014-01-01

240

Constraining Exoplanet Mass from Transmission Spectroscopy  

CERN Multimedia

Determination of an exoplanet's mass is a key to understanding its basic properties, including its potential for supporting life. To date, mass constraints for exoplanets are predominantly based on radial velocity (RV) measurements, which are not suited for planets with low masses, large semi-major axes, or those orbiting faint or active stars. Here, we present a method to extract an exoplanet's mass solely from its transmission spectrum. We find good agreement between the mass retrieved for the hot Jupiter HD189733b from transmission spectroscopy with that from RV measurements. Our method will be able to retrieve the masses of Earth-sized and super-Earth planets using data from future space telescopes that were initially designed for atmospheric characterization.

de Wit, Julien

2014-01-01

 
 
 
 
241

Theoretical spectra of terrestrial exoplanet surfaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigate spectra of airless rocky exoplanets with a theoretical framework that self-consistently treats reflection and thermal emission. We find that a silicate surface on an exoplanet is spectroscopically detectable via prominent Si-O features in the thermal emission bands of 7-13 ?m and 15-25 ?m. The variation of brightness temperature due to the silicate features can be up to 20 K for an airless Earth analog, and the silicate features are wide enough to be distinguished from atmosp...

Hu, Renyu; Ehlmann, Bethany L.; Seager, Sara

2012-01-01

242

Stellar characterization of CoRoT/Exoplanet fields with MATISSE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The homogeneous spectroscopic determination of the stellar parameters is a mandatory step for transit detections from space. Knowledge of which population the planet hosting stars belong to places constraints on the formation and evolution of exoplanetary systems. We used the FLAMES/GIRAFFE multi-fiber instrument at ESO to spectroscopically observe samples of stars in three CoRoT/Exoplanet fields, namely the LRa01, LRc01, and SRc01 fields, and characterize their stellar popu...

Gazzano, J. -c; Laverny, P.; Deleuil, M.; Recio-blanco, A.; Bouchy, F.; Moutou, C.; Bijaoui, A.; Ordenovic, C.; Gandolfi, D.; Loeillet, B.

2010-01-01

243

Deformable Mirrors Capture Exoplanet Data, Reflect Lasers  

Science.gov (United States)

To image and characterize exoplanets, Goddard Space Flight Center turned to deformable mirrors (DMs). Berkeley, California-based Iris AO, Inc. worked with Goddard through the SBIR program to improve the company’s microelectromechanical DMs, which are now being evaluated and used for biological research, industrial applications, and could even be used by drug manufacturers.

2014-01-01

244

Next Generation Transit Survey (NGTS)  

Science.gov (United States)

The Next Generation Transit Survey (NGTS) is a new ground-based survey for transiting exoplanets. Our primary goal is to find the first statistically-significant sample of Neptunes and super-Earths that are bright enough for radial velocity confirmation. By measuring precise masses and radii we will constrain the bulk composition and internal structure of planets that span the transition between the gas giants and terrestrial planets. Our brightest exoplanets will also be suitable for atmospheric characterisation with large facilities such as the VLT, JWST and the E-ELT. NGTS construction began in June 2013, and the survey is due to commence in 2014.

Wheatley, Peter J.; Pollacco, Don L.; Queloz, Didier; Rauer, Heike; Watson, Christopher A.; West, Richard G.; Chazelas, Bruno; Louden, Tom M.; Bannister, Nigel; Bento, Joao; Burleigh, Matthew; Cabrera, Juan; Eigmüller, Philipp; Erikson, Anders; Genolet, Ludovic; Goad, Michael; Grange, Andrew; Jordán, Andrés; Lawrie, Katherine; McCormac, James; Neveu, Marion; Walker, Simon

2014-01-01

245

DISCOVERING THE GROWTH HISTORIES OF EXOPLANETS: THE SATURN ANALOG HD 149026b  

International Nuclear Information System (INIS)

The transiting 'hot Saturn' HD 149026b, which has the highest mean density of any confirmed planet in the Neptune-Jupiter mass range, has challenged theories of planet formation since its discovery in 2005. Previous investigations could not explain the origin of the planet's 45-110 Earth-mass solid core without invoking catastrophes such as gas giant collisions or heavy planetesimal bombardment launched by neighboring planets. Here we show that HD 149026b's large core can be successfully explained by the standard core accretion theory of planet formation. The keys to our reconstruction of HD 149026b are (1) applying a model of the solar nebula to describe the protoplanet nursery, (2) placing the planet initially on a long-period orbit at Saturn's heliocentric distance of 9.5 AU, and (3) adjusting the solid mass in the HD 149026 disk to twice that of the solar nebula in accordance with the star's heavy element enrichment. We show that the planet's migration into its current orbit at 0.042 AU is consistent with our formation model. Our study of HD 149026b demonstrates that it is possible to discover the growth history of any planet with a well-defined core mass that orbits a solar-type star.

2009-04-20

246

Transiting exoplanets from the CoRoT space mission XXI. CoRoT-19b: A low density planet orbiting an old inactive F9V-star  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Observations of transiting extrasolar planets are of key importance to our understanding of planets because their mass, radius, and mass density can be determined. The CoRoT space mission allows us to achieve a very high photometric accuracy. By combining CoRoT data with high-precision radial velocity measurements, we derive precise planetary radii and masses. We report the discovery of CoRoT-19b, a gas-giant planet transiting an old, inactive F9V-type star with a period of four days. After e...

2012-01-01

247

Optical transmission photometry of the highly inflated exoplanet WASP-17b  

CERN Document Server

We present ground-based high-precision observations of the transit of WASP-17b using the multi-band photometer ULTRACAM on ESO's NTT in the context of performing transmission spectrophotometry of this highly inflated exoplanet. Our choice of filters (SDSS u', g' and r' bands) is designed to probe for the presence of opacity sources in the upper atmosphere. We find evidence for a wavelength dependence in the planet radius in the form of enhanced absorption in the SDSS r' band, consistent with a previously detected broad sodium feature. We present a new independent measurement of the planetary radius at Rpl = 1.97 +/- 0.06 Rjup, which confirms this planet as the most inflated exoplanet known to date. Our measurements are most consistent with an atmospheric profile devoid of enhanced TiO opacity, previously predicted to be present for this planet.

Bento, J; Copperwheat, C M; Fortney, J J; Dhillon, V S; Hickman, R; Littlefair, S P; Marsh, T R; Parsons, S G; Southworth, J

2013-01-01

248

Validation of the Exoplanet Kepler-21b using PAVO/CHARA Long-Baseline Interferometry  

CERN Multimedia

We present long-baseline interferometry of the Kepler exoplanet host star HD179070 (Kepler-21) using the PAVO beam combiner at the CHARA Array. The visibility data are consistent with a single star and exclude stellar companions at separations ~1-1000 mas (~ 0.1-113 AU) and contrasts < 3.5 magnitudes. This result supports the validation of the 1.6 R_{earth} exoplanet Kepler-21b by Howell et al. (2012) and complements the constraints set by adaptive optics imaging, speckle interferometry, and radial velocity observations to rule out false-positives due to stellar companions. We conclude that long-baseline interferometry has strong potential to validate transiting extrasolar planets, particularly for future projects aimed at brighter stars and for host stars where radial velocity follow-up is not available.

Huber, Daniel; Bedding, Timothy R; Howell, Steve B; Maestro, Vicente; Mérand, Antoine; Tuthill, Peter G; White, Timothy R; Farrington, Christopher D; Goldfinger, P J; McAlister, Harold A; Schaefer, Gail H; Sturmann, Judit; Sturmann, Laszlo; Brummelaar, Theo A ten; Turner, Nils H

2012-01-01

249

SYSTEM PARAMETERS, TRANSIT TIMES, AND SECONDARY ECLIPSE CONSTRAINTS OF THE EXOPLANET SYSTEMS HAT-P-4, TrES-2, TrES-3, and WASP-3 FROM THE NASA EPOXI MISSION OF OPPORTUNITY  

International Nuclear Information System (INIS)

As part of the NASA EPOXI Mission of Opportunity, we observed seven known transiting extrasolar planet systems in order to construct time series photometry of extremely high phase coverage and precision. Here we present the results for four 'hot-Jupiter systems' with near-solar stars-HAT-P-4, TrES-3, TrES-2, and WASP-3. We observe 10 transits of HAT-P-4, estimating the planet radius Rp = 1.332 ± 0.052 RJup, the stellar radius R* = 1.602 ± 0.061 Rsun, the inclination i = 89.67 ± 0.30 deg, and the transit duration from first to fourth contact ? = 255.6 ± 1.9 minutes. For TrES-3, we observe seven transits and find Rp = 1.320 ± 0.057 RJup, R* = 0.817 ± 0.022 Rsun, i = 81.99 ± 0.30 deg, and ? = 81.9 ± 1.1 minutes. We also note a long-term variability in the TrES-3 light curve, which may be due to star spots. We observe nine transits of TrES-2 and find Rp = 1.169 ± 0.034 RJup, R* = 0.940 ± 0.026 Rsun, i = 84.15 ± 0.16 deg, and ? = 107.3 ± 1.1 minutes. Finally, we observe eight transits of WASP-3, finding Rp = 1.385 ± 0.060 RJup, R* = 1.354 ± 0.056 Rsun, i = 84.22 ± 0.81 deg, and ? = 167.3 ± 1.3 minutes. We present refined orbital periods and times of transit for each target. We state 95% confidence upper limits on the secondary eclipse depths in our broadband visible bandpass centered on 650 nm. These limits are 0.073% for HAT-P-4, 0.062% for TrES-3, 0.16% for TrES-2, and 0.11% for WASP-3. We combine the TrES-3 secondary eclipse information with the existing published data and confirm that the atmosphere likely does not have a temperature inversion.

2011-01-10

250

High resolution transmission spectrum of the Earth's atmosphere -- Seeing Earth as an exoplanet using a lunar eclipse  

CERN Document Server

With the rapid developments in the exoplanet field, more and more terrestrial exoplanets are being detected. Characterising their atmospheres using transit observations will become a key datum in the quest for detecting an Earth-like exoplanet. The atmospheric transmission spectrum of our Earth will be an ideal template for comparison with future exo-Earth candidates. By observing a lunar eclipse, which offers a similar configuration to that of an exoplanet transit, we have obtained a high resolution and high signal-to-noise ratio transmission spectrum of the Earth's atmosphere. This observation was performed with the High Resolution Spectrograph at Xinglong Station, China during the total lunar eclipse in December 2011. We compare the observed transmission spectrum with our atmospheric model, and determine the characteristics of the various atmospheric species in detail. In the transmission spectrum, O2, O3, O2-O2, NO2 and H2O are detected, and their column densities are measured and compared with the satell...

Yan, Fei; Petr-Gotzens, Monika G; Zhao, Gang; Wang, Wei; Wang, Liang; Liu, Yujuan; Pallé, Enric

2014-01-01

251

VUV-absorption cross section of CO2 at high temperatures and impact on exoplanet atmospheres  

Directory of Open Access Journals (Sweden)

Full Text Available Ultraviolet (UV absorption cross sections are an essential ingredient of photochemical atmosphere models. Exoplanet searches have unveiled a large population of short-period objects with hot atmospheres, very different from what we find in our solar system. Transiting exoplanets whose atmospheres can now be studied by transit spectroscopy receive extremely strong UV fluxes and have typical temperatures ranging from 400 to 2500 K. At these temperatures, UV photolysis cross section data are severely lacking. Our goal is to provide high-temperature absorption cross sections and their temperature dependency for important atmospheric compounds. This study is dedicated to CO2, which is observed and photodissociated in exoplanet atmospheres. We performed these measurements for the 115 - 200 nm range at 300, 410, 480, and 550 K. In the 195 - 230 nm range, we worked at seven temperatures between 465 and 800 K. We found that the absorption cross section of CO2 is very sensitive to temperature, especially above 160 nm. Within the studied range of temperature, the CO2 cross section can vary by more than two orders of magnitude. This, in particular, makes the absorption of CO2 significant up to wavelengths as high as 230 nm, while it is negligible above 200 nm at 300 K. To investigate the influence of these new data on the photochemistry of exoplanets, we implemented the measured cross section into a 1D photochemical model. The model predicts that accounting for this temperature dependency of CO2 cross section can affect the computed abundances of NH3, CO2, and CO by one order of magnitude in the atmospheres of hot Jupiter and hot Neptune.

Venot Olivia

2014-02-01

252

Observing Exoplanets in the Mid-Ultraviolet  

Science.gov (United States)

There are good reasons for pushing the spectral range of observation to shorter wavelengths than currently envisaged for terrestrial planet-finding missions utilizing with a 4-m, diffraction-limited, optical telescope: (1) The angular resolution is higher, so the image of an exoplanet is better separated from that of the much brighter star. (2) The exozodiacal background per resolution element is smaller, so exposure times are reduced for the same incident flux. (3) Most importantly, the sensitivity to the ozone biomarker is increased by several hundred-fold by access to the ozone absorption band at 250-300 nm. These benefits must be weighed against challenges arising from the faintness of exoplanets in the mid-UV. We will evaluate both the technical and cost challenges including image quality of large telescopes, advanced mirror coatings and innovative designs for enhanced optical throughput, and CCD detectors optimized for 250-400 nm.

Heap. Sara

2008-01-01

253

Astrometric detection of exoplanets from the ground  

CERN Multimedia

Astrometry is a powerful technique to study the populations of extrasolar planets around nearby stars. It gives access to a unique parameter space and is therefore required for obtaining a comprehensive picture of the properties, abundances, and architectures of exoplanetary systems. In this review, we discuss the scientific potential, present the available techniques and instruments, and highlight a few results of astrometric planet searches, with an emphasis on observations from the ground. In particular, we discuss astrometric observations with the Very Large Telescope (VLT) Interferometer and a programme employing optical imaging with a VLT camera, both aimed at the astrometric detection of exoplanets. Finally, we set these efforts into the context of Gaia, ESA's astrometry mission scheduled for launch in 2013, and present an outlook on the future of astrometric exoplanet detection from the ground.

Sahlmann, J; Mérand, A; Queloz, D; Ségransan, D; Woillez, J

2013-01-01

254

THEORETICAL SPECTRA OF TERRESTRIAL EXOPLANET SURFACES  

Energy Technology Data Exchange (ETDEWEB)

We investigate spectra of airless rocky exoplanets with a theoretical framework that self-consistently treats reflection and thermal emission. We find that a silicate surface on an exoplanet is spectroscopically detectable via prominent Si-O features in the thermal emission bands of 7-13 {mu}m and 15-25 {mu}m. The variation of brightness temperature due to the silicate features can be up to 20 K for an airless Earth analog, and the silicate features are wide enough to be distinguished from atmospheric features with relatively high resolution spectra. The surface characterization thus provides a method to unambiguously identify a rocky exoplanet. Furthermore, identification of specific rocky surface types is possible with the planet's reflectance spectrum in near-infrared broad bands. A key parameter to observe is the difference between K-band and J-band geometric albedos (A{sub g}(K) - A{sub g}(J)): A{sub g}(K) - A{sub g}(J) > 0.2 indicates that more than half of the planet's surface has abundant mafic minerals, such as olivine and pyroxene, in other words primary crust from a magma ocean or high-temperature lavas; A{sub g}(K) - A{sub g}(J) < -0.09 indicates that more than half of the planet's surface is covered or partially covered by water ice or hydrated silicates, implying extant or past water on its surface. Also, surface water ice can be specifically distinguished by an H-band geometric albedo lower than the J-band geometric albedo. The surface features can be distinguished from possible atmospheric features with molecule identification of atmospheric species by transmission spectroscopy. We therefore propose that mid-infrared spectroscopy of exoplanets may detect rocky surfaces, and near-infrared spectrophotometry may identify ultramafic surfaces, hydrated surfaces, and water ice.

Hu Renyu; Seager, Sara [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Ehlmann, Bethany L., E-mail: hury@mit.edu [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)

2012-06-10

255

EChO - Exoplanet Characterisation Observatory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A dedicated mission to investigate exoplanetary atmospheres represents a major milestone in our quest to understand our place in the universe by placing our Solar System in context and by addressing the suitability of planets for the presence of life. EChO -the Exoplanet Characterisation Observatory- is a mission concept specifically geared for this purpose. EChO will provide simultaneous, multi-wavelength spectroscopic observations on a stable platform that will allow very ...

Tinetti, G.; Beaulieu, J. P.; Henning, T.; Meyer, M.; Micela, G.; Ribas, I.; Stam, D.; Swain, M.; Krause, O.; Ollivier, M.; Pace, E.; Swinyard, B.; Aylward, A.; Boekel, R.; Coradini, A.

2011-01-01

256

Theoretical Spectra of Terrestrial Exoplanet Surfaces  

CERN Document Server

We investigate spectra of airless rocky exoplanets with a theoretical framework that self-consistently treats reflection and thermal emission. We find that a silicate surface on an exoplanet is spectroscopically detectable via prominent Si-O features in the thermal emission bands of 7 - 13 \\mu m and 15 - 25 \\mu m. The variation of brightness temperature due to the silicate features can be up to 20 K for an airless Earth analog, and the silicate features are wide enough to be distinguished from atmospheric features with relatively high-resolution spectra. The surface characterization thus provides a method to unambiguously identify a rocky exoplanet. Furthermore, identification of specific rocky surface types is possible with the planet's reflectance spectrum in near-infrared broad bands. A key parameter to observe is the difference between K band and J band geometric albedos (A_g (K)-A_g (J)): A_g (K)-A_g (J) > 0.2 indicates that more than half of the planet's surface has abundant mafic minerals, such as oliv...

Hu, Renyu; Seager, Sara

2012-01-01

257

Mass-Radius Relationships for Solid Exoplanets  

CERN Document Server

We use new interior models of cold planets to investigate the mass-radius relationships of solid exoplanets, considering planets made primarily of iron, silicates, water, and carbon compounds. We find that the mass-radius relationships for cold terrestrial-mass planets of all compositions we considered follow a generic functional form that is not a simple power law: $\\log_{10} R_s = k_1 + 1/3 \\log_{10}(M_s) - k_2 M_s^{k_3}$ for up to $M_p \\approx 20 M_{\\oplus}$, where $M_s$ and $R_s$ are scaled mass and radius values. This functional form arises because the common building blocks of solid planets all have equations of state that are well approximated by a modified polytrope of the form $\\rho = \\rho_0 + c P^n$. We find that highly detailed planet interior models, including temperature structure and phase changes, are not necessary to derive solid exoplanet bulk composition from mass and radius measurements. For solid exoplanets with no substantial atmosphere we have also found that: with 5% fractional uncertai...

Seager, S; Hier-Majumder, C; Militzer, B

2007-01-01

258

A search for transit timing variation  

CERN Document Server

Photometric follow-ups of transiting exoplanets (TEPs) may lead to discoveries of additional, less massive bodies in extrasolar systems. This is possible by detecting and then analysing variations in transit timing of transiting exoplanets. In 2009 we launched an international observing campaign, the aim of which is to detect and characterise signals of transit timing variation (TTV) in selected TEPs. The programme is realised by collecting data from 0.6--2.2-m telescopes spread worldwide at different longitudes. We present our observing strategy and summarise first results for WASP-3b with evidence for a 15 Earth-mass perturber in an outer 2:1 orbital resonance.

Maciejewski, G; Raetz, St; Errmann, R; Kramm, U; Schmidt, T O B

2010-01-01

259

Transiting exoplanets from the CoRoT space mission XXV. C0R0T-27b: a massive and dense planet on a short-period orbit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Aims. We report the discovery of a massive and dense transiting planet CoRoT-27b on a 3.58-day orbit around a 4.2 Gyr-old G2 star. The planet candidate was identified from the CoRoT photometry, and was confirmed as a planet with ground-based spectroscopy. Methods. The confirmation of the planet candidate is based on radial velocity observations combined with imaging to rule out blends. The characterisation of the planet and its host star was carried out using a Bayesian approach where all the...

2014-01-01

260

Detection of orbital parameter changes in the TrES-2 exoplanet ?  

CERN Multimedia

We report a possible change in the orbit parameters of the TrES-2 exoplanet. With a period of 2.470621 days, the TrES-2 exoplanet exhibits almost "grazing" transits 110.4 minutes duration as measured in 2006 by Holman and collaborators. We observed two transits of TrES-2 in 2008 using the 1.2m Oskar-Luhning telescope (OLT) of Hamburg observatory employing CCD photometry in an i-band and a near to R-band filter. A careful light curve analysis including a re-analysis of the 2006 observations shows that the current transit duration has shortened since 2006 by ~ 3.16 minutes. Although the new observations were taken in a different filter we argue that the observed change in transit duration time cannot be attributed to the treatment of limb darkening. If we assume the stellar and planetary radii to be constant, a change in orbit inclination is the most likely cause of this change in transit duration.

Mislis, D

2009-01-01

 
 
 
 
261

The Transit Monitoring in the South (TraMoS project  

Directory of Open Access Journals (Sweden)

Full Text Available We present the Transit Monitoring in the South (TraMoS project. TraMoS has monitored transits of 30 exoplanets with telescopes located in Chile since 2008, whit the following goals: (1 to refine the physical and/or orbital parameters of those exoplanet system, and (2 to search for variations in the mid-times of the transits and in other parameters such as orbital inclination or transit's depth, that could indicate the presence of additional bodies in the system. We highlight here the first results of TraMoS in three selected exoplanets.

López-Morales Mercedes

2013-04-01

262

The NASA/IPAC/NExScI Star and Exoplanet Database  

CERN Document Server

The NASA/IPAC/NExScI Star and Exoplanet Database (NStED) is a general purpose stellar archive which supports NASA planet-finding and planet-characterization goals, stellar astrophysics, and the planning of NASA and other space missions. There are two principal components of NStED: a database of 140,000 nearby stars and exoplanet-hosting stars, and an archive dedicated to high precision photometric surveys for transiting exoplanets (NStED-ETSS). We present summaries of these components. The NStED stellar database currently serves published parameters for 140,000 stars. These parameters include coordinates, multiplicity, proper motion, parallax, spectral type, multiband photometry, radial velocity, metallicity, chromospheric and coronal activity index, rotation velocity/period, infrared excess. NStED-ETSS currently serves data from the TrES survey of the Kepler field as well as dedicated photometric surveys of four stellar clusters. NStED-ETSS aims to serve both the surveys and the broader astronomical communit...

Berriman, G B; Baker, R; Von Braun, K; Chiu, N-M; Ciardi, D R; Good, J; Kane, S R; Kong, M; Laity, A C; McElroy, D L; Monkewitz, S; Payne, A N; Ramírez, S; Schmitz, M; Stauffer, J S; Wyatt, P L

2009-01-01

263

Characterizing Exoplanet Atmospheres : A Complete Line List for Phosphine  

Science.gov (United States)

The ability to characterise the atmospheres of cool stars, brown dwarfs and exoplanets requires fundamental data for all species contributing significantly to their opacity. However, with notable exceptions such as water and ammonia, existing molecular line lists are not sufficiently accurate or complete to allow for a full spectroscopic analysis of these bodies. ExoMol (www.exomol.com [1]) is a project that aims to rectify this by generating comprehensive line lists for all molecules likely to be detected in the atmospheres of cool astrophysical objects in the foreseeable future. The spectral data is generated by employing ab initio quantum mechanical methods, performing empirical refinement based on experimental spectroscopic data and harnessing high performance computing. Here we present our work on phosphine, (PH3), an equilateral pyramidal molecule (the phosphorus analogue to ammonia). Phosphine is known to be important for the atmospheres of giant-planets, cool stars and many other astronomical bodies. Rotational transition features of phosphine have been found in the far- infrared spectra of Saturn and Jupiter [2, 3], where it is a marker for vertical convection zones. A computed room temperature line list of phosphine is presented here [4], illustrated in the accompanying figure 1. This line list is a precursor to a high temperature equivalent to be produced in the near future, necessary for the analysis of cool stars and brown dwarfs. All the transitions' energy levels and Einstein A-coefficients were computed using the program TROVE [5].

Sousa-Silva, C.; Yurchenko, S. N.; Tennyson, J.

2013-09-01

264

ExoplanetSat: Detecting transiting exoplanets using a low-cost CubeSat platform  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nanosatellites, i.e. spacecraft that weigh between 1 and 10 kg, are drawing increasing interest as platforms for conducting on-orbit science. This trend is primarily driven by the ability to piggyback nanosatellites on the launch of large spacecraft and hence achieve orbit at greatly reduced cost. The CubeSat platform is a standardized nanosatellite configuration, consisting of one, two, or three 10 cm x 10 cm x 10 cm units (1, 2, or 3 "U"s) arranged in a row. We present a CubeSat-based conce...

Smith, Matthew William; Seager, Sara; Pong, Christopher Masaru; Villasenor, Jesus Noel Samonte; Ricker, George R.; Miller, David W.; Knapp, Mary E.; Farmer, Grant Trapnell; Jensen-clem, Rebecca M.

2010-01-01

265

New Exoplanet Surveys in the Canadian High Arctic at 80 Degrees North  

Science.gov (United States)

Observations from near the Eureka station on Ellesmere Island, in the Canadian High Arctic at 80° North, benefit from 24-hour darkness combined with dark skies and long cloud-free periods during the winter. Our first astronomical surveys conducted at the site are aimed at transiting exoplanets; compared to mid-latitude sites, the continuous darkness during the Arctic winter greatly improves the survey’s detection effciency for longer-period transiting planets. We detail the design, construction, and testing of the first two instruments: a robotic telescope, and a set of very wide-field imaging cameras. The 0.5m Dunlap Institute Arctic Telescope has a 0.8-square-degree field of view and is designed to search for potentially habitable exoplanets around low-mass stars. The very wide field cameras have several-hundred-square-degree fields of view pointed at Polaris, are designed to search for transiting planets around bright stars, and were tested at the site in February 2012. Finally, we present a conceptual design for the Compound Arctic Telescope Survey (CATS), a multiplexed transient and transit search system which can produce a 10,000-square-degree snapshot image every few minutes throughout the Arctic winter.

Law, Nicholas M.; Sivanandam, Suresh; Murowinski, Richard; Carlberg, Raymond; Ngan, Wayne; Salbi, Pegah; Ahmadi, Aida; Steinbring, Eric; Halman, Mark; Graham, James

2012-09-01

266

Innovations for Exoplanet Data Acquisition  

Science.gov (United States)

Extra-solar planets are detected through the analysis of light fluctuations from a star. During a planetary transit, a star's magnitude decreases slightly, which, when plotted against the time, appears as a small dip in its light curve. In order to find the stars’ magnitudes over time and plot light curves, one must go through a time consuming process called photometry on each image for every star. Through the use of the Image Reduction and Analysis Facility (IRAF) command language and scripting tools, I have been able to develop a program, called brightER, that greatly reduces the amount of time spent gathering this information. It combines the entire photometric process into one compact package, automates multiple steps of that process, and has guided instructions throughout. Through the use of brightER, we can spend less time acquiring magnitudes and more time analyzing them.

Ranquist, Emily; Stephens, D. C.; Rawlins, J.

2013-06-01

267

The Ultraviolet Radiation Environment around M dwarf Exoplanet Host Stars  

Science.gov (United States)

The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. Ultraviolet photons influence the atmospheric temperature profiles and production of potential biomarkers on Earth-like planets around these stars. At present, little observational or theoretical basis exists for understanding the ultraviolet spectra of M dwarfs, despite their critical importance to predicting and interpreting the spectra of potentially habitable planets as they are obtained in the coming decades. Using observations from the Hubble Space Telescope, we present a study of the UV radiation fields around nearby M dwarf planet hosts that covers both far-UV (FUV) and near-UV (NUV) wavelengths. The combined FUV+NUV spectra are publicly available in machine-readable format. We find that all six exoplanet host stars in our sample (GJ 581, GJ 876, GJ 436, GJ 832, GJ 667C, and GJ 1214) exhibit some level of chromospheric and transition region UV emission. No "UV-quiet" M dwarfs are observed. The bright stellar Ly? emission lines are reconstructed, and we find that the Ly? line fluxes comprise ~37%-75% of the total 1150-3100 Å flux from most M dwarfs; gsim103 times the solar value. We develop an empirical scaling relation between Ly? and Mg II emission, to be used when interstellar H I attenuation precludes the direct observation of Ly?. The intrinsic unreddened flux ratio is F(Ly?)/F(Mg II) = 10 ± 3. The F(FUV)/F(NUV) flux ratio, a driver for abiotic production of the suggested biomarkers O2 and O3, is shown to be ~0.5-3 for all M dwarfs in our sample, >103 times the solar ratio. For the four stars with moderate signal-to-noise Cosmic Origins Spectrograph time-resolved spectra, we find UV emission line variability with amplitudes of 50%-500% on 102-103 s timescales. This effect should be taken into account in future UV transiting planet studies, including searches for O3 on Earth-like planets. Finally, we observe relatively bright H2 fluorescent emission from four of the M dwarf exoplanetary systems (GJ 581, GJ 876, GJ 436, and GJ 832). Additional modeling work is needed to differentiate between a stellar photospheric or possible exoplanetary origin for the hot (T(H2) ? 2000-4000 K) molecular gas observed in these objects. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

France, Kevin; Froning, Cynthia S.; Linsky, Jeffrey L.; Roberge, Aki; Stocke, John T.; Tian, Feng; Bushinsky, Rachel; Désert, Jean-Michel; Mauas, Pablo; Vieytes, Mariela; Walkowicz, Lucianne M.

2013-02-01

268

THE ULTRAVIOLET RADIATION ENVIRONMENT AROUND M DWARF EXOPLANET HOST STARS  

Energy Technology Data Exchange (ETDEWEB)

The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. Ultraviolet photons influence the atmospheric temperature profiles and production of potential biomarkers on Earth-like planets around these stars. At present, little observational or theoretical basis exists for understanding the ultraviolet spectra of M dwarfs, despite their critical importance to predicting and interpreting the spectra of potentially habitable planets as they are obtained in the coming decades. Using observations from the Hubble Space Telescope, we present a study of the UV radiation fields around nearby M dwarf planet hosts that covers both far-UV (FUV) and near-UV (NUV) wavelengths. The combined FUV+NUV spectra are publicly available in machine-readable format. We find that all six exoplanet host stars in our sample (GJ 581, GJ 876, GJ 436, GJ 832, GJ 667C, and GJ 1214) exhibit some level of chromospheric and transition region UV emission. No 'UV-quiet' M dwarfs are observed. The bright stellar Ly{alpha} emission lines are reconstructed, and we find that the Ly{alpha} line fluxes comprise {approx}37%-75% of the total 1150-3100 A flux from most M dwarfs; {approx}>10{sup 3} times the solar value. We develop an empirical scaling relation between Ly{alpha} and Mg II emission, to be used when interstellar H I attenuation precludes the direct observation of Ly{alpha}. The intrinsic unreddened flux ratio is F(Ly{alpha})/F(Mg II) = 10 {+-} 3. The F(FUV)/F(NUV) flux ratio, a driver for abiotic production of the suggested biomarkers O{sub 2} and O{sub 3}, is shown to be {approx}0.5-3 for all M dwarfs in our sample, >10{sup 3} times the solar ratio. For the four stars with moderate signal-to-noise Cosmic Origins Spectrograph time-resolved spectra, we find UV emission line variability with amplitudes of 50%-500% on 10{sup 2}-10{sup 3} s timescales. This effect should be taken into account in future UV transiting planet studies, including searches for O{sub 3} on Earth-like planets. Finally, we observe relatively bright H{sub 2} fluorescent emission from four of the M dwarf exoplanetary systems (GJ 581, GJ 876, GJ 436, and GJ 832). Additional modeling work is needed to differentiate between a stellar photospheric or possible exoplanetary origin for the hot (T(H{sub 2}) Almost-Equal-To 2000-4000 K) molecular gas observed in these objects.

France, Kevin; Froning, Cynthia S.; Stocke, John T.; Bushinsky, Rachel [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Linsky, Jeffrey L. [JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309 (United States); Roberge, Aki [Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Tian, Feng [Center for Earth System Sciences, Tsinghua University, Beijing 100084 (China); Desert, Jean-Michel [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Mauas, Pablo; Vieytes, Mariela [Instituto de Astronomsica del Espacio (CONICET-UBA), C.C. 67 Sucursal 28, 1428 Buenos Aires (Argentina); Walkowicz, Lucianne M., E-mail: kevin.france@colorado.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2013-02-15

269

Exoplanet atmospheres with EChO: spectral retrievals using EChOSim  

CERN Multimedia

We demonstrate the effectiveness of the Exoplanet Characterisation Observatory mission concept for constraining the atmospheric properties of hot and warm gas giants and super Earths. Synthetic primary and secondary transit spectra for a range of planets are passed through EChOSim (Waldmann & Pascale 2014) to obtain the expected level of noise for different observational scenarios; these are then used as inputs for the NEMESIS atmospheric retrieval code and the retrieved atmospheric properties (temperature structure, composition and cloud properties) compared with the known input values, following the method of Barstow et al. (2013a). To correctly retrieve the temperature structure and composition of the atmosphere to within 2 {\\sigma}, we find that we require: a single transit or eclipse of a hot Jupiter orbiting a sun-like (G2) star at 35 pc to constrain the terminator and dayside atmospheres; 20 transits or eclipses of a warm Jupiter orbiting a similar star; 10 transits/eclipses of a hot Neptune orbiti...

Barstow, Joanna K; Aigrain, Suzanne; Fletcher, Leigh N; Irwin, Patrick G J; Varley, Ryan; Pascale, Enzo

2014-01-01

270

Exploring Earth as an Exoplanet (Invited)  

Science.gov (United States)

Earth is our only example of a habitable planet, or a planet capable of maintaining liquid water on its surface. As a result, Earth serves as the archetypal habitable world in conceptual studies of future exoplanet characterization missions, or in studies of techniques for the remote characterization of potentially habitable exoplanets. Pioneering studies of a distant Earth used spatially resolved observations from the Galileo Earth encounters. However, for the foreseeable future, direct observations of exoplanets will be spatially unresolved, depicting their targets as points of light. As a consequence, characterization techniques will be limited to using disk integrated spectroscopic observations, as well as rotational and orbital light curves. This challenge offers a unique opportunity for collaborations between the Earth sciences and the astronomical sciences, working together to retrieve information from spectra of Earth-like worlds seen at interstellar distances. There are a number of existing observations of the distant Earth that can be used to test our ability to remotely characterize the environment of a habitable exoplanet, including its surface temperature and the presence of an ocean. However, such datasets are rare, and are often limited in wavelength range, spectral resolution, temporal coverage, and viewing geometry. As a result, models of Earth's disk-integrated spectrum provide the best means for understanding the appearance of the Pale Blue Dot, and can serve as suitable replacements for data in characterization studies. One such model is the Virtual Planetary Laboratory three-dimensional, line-by-line, multiple-scattering spectral Earth model. This model incorporates realistic absorption and scattering by the atmosphere and surface, including specular reflectance from the ocean, and direction-dependent scattering by clouds and aerosols. Data from Earth-observing satellites are used to specify the time- and location-dependent state of the surface and atmosphere. The model has been extensively validated against observations of our planet, including data from the NASA LCROSS and EPOXI missions, the Atmospheric Infrared Sounder instrument aboard the NASA Aqua satellite, as well as Earthshine observations of the lunar night side. This community tool can now be used to study the appearance, and characterization, of the distant Earth across a wide range of wavelengths, viewing geometries, and timescales.

Robinson, T. D.; Meadows, V. S.; Crisp, D.

2013-12-01

271

Exoplanets Bouncing Between Binary Stars  

CERN Document Server

Exoplanetary systems are found not only among single stars, but also binaries of widely varying parameters. Binaries with separations of 100--1000 au are prevalent in the Solar neighborhood; at these separations planet formation around a binary member may largely proceed as if around a single star. During the early dynamical evolution of a planetary system, planet--planet scattering can eject planets from a star's grasp. In a binary, the motion of a planet ejected from one star has effectively entered a restricted three-body system consisting of itself and the two stars, and the equations of motion of the three body problem will apply as long as the ejected planet remains far from the remaining planets. Depending on its energy, escape from the binary as a whole may be impossible or delayed until the three-body approximation breaks down, and further close interactions with its planetary siblings boost its energy when it passes close to its parent star. Until then this planet may be able to transition from the ...

Moeckel, Nickolas

2012-01-01

272

PynPoint Code for Exoplanet Imaging  

CERN Document Server

We announce the public release of PynPoint, a Python package that we have developed for analysing exoplanet data taken with the angular differential imaging observing technique. In particular, PynPoint is designed to model the point spread function of the central star and to subtract its flux contribution to reveal nearby faint companion planets. The current version of the package does this correction by using a principal component analysis method to build a basis set for modelling the point spread function of the observations. We demonstrate the performance of the package by reanalysing publicly available data on the exoplanet beta Pictoris b, which consists of close to 24,000 individual image frames. We show that PynPoint is able to analyse this typical data in roughly 1.5 minutes on a Mac Pro, when the number of images is reduced by co-adding in sets of 5. The main computational work parallelises well as a result of a reliance on SciPy and NumPy functions. For this calculation the peak memory load is 6Gb, ...

Amara, Adam; Akeret, Joel

2014-01-01

273

Rotation periods of exoplanet host stars  

CERN Multimedia

The stellar rotation periods of ten exoplanet host stars have been determined using newly analysed Ca II H & K flux records from Mount Wilson Observatory and Stromgren b, y photometric measurements from Tennessee State University's automatic photometric telescopes (APTs) at Fairborn Observatory. Five of the rotation periods have not previously been reported, with that of HD 130322 very strongly detected at Prot = 26.1 \\pm 3.5 d. The rotation periods of five other stars have been updated using new data. We use the rotation periods to derive the line-of-sight inclinations of the stellar rotation axes, which may be used to probe theories of planet formation and evolution when combined with the planetary orbital inclination found from other methods. Finally, we estimate the masses of fourteen exoplanets under the assumption that the stellar rotation axis is aligned with the orbital axis. We calculate the mass of HD 92788 b (28 MJ) to be within the low-mass brown dwarf regime and suggest that this object warra...

Simpson, Elaine; Henry, Greg; Watson, Chris

2010-01-01

274

Exoplanets finding, exploring, and understanding alien worlds  

CERN Document Server

Since 1992 there has been an explosion in the discovery of planets orbiting stars other than the Sun. There are now around 600 alien planets that we know about and that number is likely to break through the 1,000 ‘barrier’ within a couple of years. The recent launch of the Kepler space telescope specifically to look for new worlds opens the prospect of hundreds, maybe thousands, of further exoplanets being found. Many of these planets orbits stars that are not too different from the Sun, but they are so close in to their stars that their surfaces could be flooded with seas of molten lead – or even molten iron. Others orbit so far from their stars that they might as well be alone in interstellar space. A planet closely similar to the Earth has yet to be detected, but that (to us) epoch-making discovery is just a matter of time. Could these alien worlds could provide alternative homes for humankind, new supplies of mineral resources and might they might already be homes to alien life? Exoplanets: Finding,...

Kitchin, Chris

2012-01-01

275

MEMS and the direct detection of exoplanets  

Science.gov (United States)

Deformable mirrors, and particularly MEMS, are crucial components for the direct imaging of exoplanets for both ground-based and space-based instruments. Without deformable mirrors, coronagraphs are incapable of reaching contrasts required to image Jupiter-like planets. The system performance is limited by image quality degradation resulting from wavefront error introduced from multiple effects including: atmospheric turbulence, static aberrations in the system, non-common-path aberrations, all of which vary with time. Correcting for these effects requires a deformable mirror with fast response and numerous actuators having moderate stroke. Not only do MEMS devices fulfill this requirement but their compactness permits their application in numerous space- and ground-based instruments, which are often volume- and mass-limited. In this paper, I will briefly explain how coronagraphs work and their requirements. I then will discuss the Extreme Adaptive Optics needed to compensate for the introduced wavefront error and how MEMS devices are a good choice to achieve the performance needed to produce the contrasts necessary to detect exoplanets. As examples, I will discuss a facility instrument for the Gemini Observatory, called the Gemini Planet Imager, that will detect Jupiter-like planets and present recent results from the NASA Ames Coronagraph Experiment laboratory, in the context of a proposed space- based mission called EXCEDE. EXCEDE is planned to focus on protoplanetary disks.

Thomas, Sandrine J.; Macintosh, Bruce; Belikov, Ruslan

2014-03-01

276

Characterization of Kepler Exoplanet Host Stars  

Science.gov (United States)

Using a sample of 220 Exoplanet host stars in the Kepler field for which spectroscopic properties have been determined, we examine their spatial, physical, and time variable properties. Covering effective temperatures from 4670K to 6400K (K4 to F4) and masses from 0.7 to 1.4 M-sun, this sample represents host stars covering the entire Kepler field of view. The majority of the host stars contain one or more Earth-sized exoplanet and range in log g from 4.0 to 4.7 and [Fe/H] from -02.4 to +0.3. Using Yale-Yonsei isochrone fits and photometric information form the Howell-Everett UBV survey of the Kepler field, we examine a complete set of parameters for these stars including their likely residence in the thin or thick disk of the Galaxy. the variability of this sample, in terms of time sale and amplitude, is examined as well.

Howell, Steve B.; Everett, M.; Ciardi, D. R.; Silva, D.; Szkody, P.

2014-01-01

277

M dwarf stars in the light of (future) exoplanet searches  

CERN Document Server

We present a brief overview of a splinter session on M dwarf stars as planet hosts that was organized as part of the Cool Stars 17 conference. The session was devoted to reviewing our current knowledge of M dwarf stars and exoplanets in order to prepare for current and future exoplanet searches focusing in low mass stars. We review the observational and theoretical challenges to characterize M dwarf stars and the importance of accurate fundamental parameters for the proper characterization of their exoplanets and our understanding on planet formation.

Rojas-Ayala, B; Mann, A W; Lépine, S; Gaidos, E; Bonfils, X; Helling, Ch; Henry, T J; Rogers, L A; von Braun, K; Youdin, A

2012-01-01

278

Search for Life Beyond the Solar System. Exoplanets, Biosignatures & Instruments  

Science.gov (United States)

Motivated by the rapidly increasing number of known Earth-sized planets, the increasing range of extreme conditions in which life on Earth can persist, and the progress toward a technology that will ultimately enable the search for life on exoplanets, the Vatican Observatory and the Steward Observatory announce a major conference entitled The Search for Life Beyond the Solar System: Exoplanets, Biosignatures & Instruments. The goal of the conference is to bring together the interdisciplinary community required to address this multi-faceted challenge: experts on exoplanet observations, early and extreme life on Earth, atmospheric biosignatures, and planet-finding telescopes.

Apai, Daniel; Gabor, Pavel

2014-03-01

279

New Exoplanet Surveys in the Canadian High Arctic at 80 Degrees North  

CERN Document Server

Observations from near the Eureka station on Ellesmere Island, in the Canadian High Arctic at 80 degrees North, benefit from 24-hour darkness combined with dark skies and long cloud-free periods during the winter. Our first astronomical surveys conducted at the site are aimed at transiting exoplanets; compared to mid-latitude sites, the continuous darkness during the Arctic winter greatly improves the survey's detection efficiency for longer-period transiting planets. We detail the design, construction, and testing of the first two instruments: a robotic telescope, and a set of very wide-field imaging cameras. The 0.5m Dunlap Institute Arctic Telescope has a 0.8-square-degree field of view and is designed to search for potentially habitable exoplanets around low-mass stars. The very wide field cameras have several-hundred-square-degree fields of view pointed at Polaris, are designed to search for transiting planets around bright stars, and were tested at the site in February 2012. Finally, we present a concep...

Law, Nicholas M; Murowinski, Richard; Carlberg, Raymond; Ngan, Wayne; Salbi, Pegah; Ahmadi, Aida; Steinbring, Eric; Halman, Mark; Graham, James

2012-01-01

280

EXOPLANETS FROM THE ARCTIC: THE FIRST WIDE-FIELD SURVEY AT 80 Degree-Sign N  

Energy Technology Data Exchange (ETDEWEB)

Located within 10 Degree-Sign of the North Pole, northern Ellesmere Island offers continuous darkness in the winter months. This capability can greatly enhance the detection efficiency of planetary transit surveys and other time domain astronomy programs. We deployed two wide-field cameras at 80 Degree-Sign N, near Eureka, Nunavut, for a 152 hr observing campaign in 2012 February. The 16 megapixel camera systems were based on commercial f/1.2 lenses with 70 mm and 42 mm apertures, and they continuously imaged 504 and 1295 deg{sup 2}, respectively. In total, the cameras took over 44,000 images and produced better than 1% precision light curves for approximately 10,000 stars. We describe a new high-speed astrometric and photometric data reduction pipeline designed for the systems, test several methods for the precision flat fielding of images from very-wide-angle cameras, and evaluate the cameras' image qualities. We achieved a scintillation-limited photometric precision of 1%-2% in each 10 s exposure. Binning the short exposures into 10 minute chunks provided a photometric stability of 2-3 mmag, sufficient for the detection of transiting exoplanets around the bright stars targeted by our survey. We estimate that the cameras, when operated over the full Arctic winter, will be capable of discovering several transiting exoplanets around bright (m{sub V} < 9.5) stars.

Law, Nicholas M.; Sivanandam, Suresh [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Carlberg, Raymond; Salbi, Pegah; Ngan, Wai-Hin Wayne; Kerzendorf, Wolfgang [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Ahmadi, Aida [University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4 (Canada); Steinbring, Eric; Murowinski, Richard, E-mail: law@di.utoronto.ca [National Science Infrastructure, National Research Council Canada, Victoria, British Columbia, V9E 2E7 (Canada)

2013-03-15

 
 
 
 
281

EXOPLANETS FROM THE ARCTIC: THE FIRST WIDE-FIELD SURVEY AT 80°N  

International Nuclear Information System (INIS)

Located within 10° of the North Pole, northern Ellesmere Island offers continuous darkness in the winter months. This capability can greatly enhance the detection efficiency of planetary transit surveys and other time domain astronomy programs. We deployed two wide-field cameras at 80°N, near Eureka, Nunavut, for a 152 hr observing campaign in 2012 February. The 16 megapixel camera systems were based on commercial f/1.2 lenses with 70 mm and 42 mm apertures, and they continuously imaged 504 and 1295 deg2, respectively. In total, the cameras took over 44,000 images and produced better than 1% precision light curves for approximately 10,000 stars. We describe a new high-speed astrometric and photometric data reduction pipeline designed for the systems, test several methods for the precision flat fielding of images from very-wide-angle cameras, and evaluate the cameras' image qualities. We achieved a scintillation-limited photometric precision of 1%-2% in each 10 s exposure. Binning the short exposures into 10 minute chunks provided a photometric stability of 2-3 mmag, sufficient for the detection of transiting exoplanets around the bright stars targeted by our survey. We estimate that the cameras, when operated over the full Arctic winter, will be capable of discovering several transiting exoplanets around bright (mV < 9.5) stars.

2013-03-01

282

VAPORIZATION OF THE EARTH: APPLICATION TO EXOPLANET ATMOSPHERES  

Energy Technology Data Exchange (ETDEWEB)

Currently, there are about three dozen known super-Earths (M < 10 M{sub Circled-Plus }), of which eight are transiting planets suitable for atmospheric follow-up observations. Some of the planets are exposed to extreme temperatures as they orbit close to their host stars, e.g., CoRot-7b, and all of these planets have equilibrium temperatures significantly hotter than the Earth. Such planets can develop atmospheres through (partial) vaporization of their crustal and/or mantle silicates. We investigated the chemical equilibrium composition of such heated systems from 500 to 4000 K and total pressures from 10{sup -6} to 10{sup +2} bars. The major gases are H{sub 2}O and CO{sub 2} over broad temperature and pressure ranges, and Na, K, O{sub 2}, SiO, and O at high temperatures and low pressures. We discuss the differences in atmospheric composition arising from vaporization of SiO{sub 2}-rich (i.e., felsic) silicates (like Earth's continental crust) and MgO-, FeO-rich (i.e., mafic) silicates (like the bulk silicate Earth). The computational results will be useful in planning spectroscopic studies of the atmospheres of Earth-like exoplanets.

Schaefer, Laura; Lodders, Katharina; Fegley, Bruce, E-mail: laura_s@wustl.edu, E-mail: lschaefer@cfa.harvard.edu, E-mail: lodders@wustl.edu, E-mail: bfegley@wustl.edu [Planetary Chemistry Laboratory, Department of Earth and Planetary Sciences and McDonnell Center for the Space Sciences, Washington University, St. Louis, MO 63130 (United States)

2012-08-10

283

MASSIVE SATELLITES OF CLOSE-IN GAS GIANT EXOPLANETS  

International Nuclear Information System (INIS)

We study the orbits, tidal heating and mass loss from satellites around close-in gas giant exoplanets. The focus is on large satellites which are potentially observable by their transit signature. We argue that even Earth-size satellites around hot Jupiters can be immune to destruction by orbital decay; detection of such a massive satellite would strongly constrain theories of tidal dissipation in gas giants, in a manner complementary to orbital circularization. The star's gravity induces significant periodic eccentricity in the satellite's orbit. The resulting tidal heating rates, per unit mass, are far in excess of Io's and dominate radioactive heating out to planet orbital periods of months for reasonable satellite tidal Q. Inside planet orbital periods of about a week, tidal heating can completely melt the satellite. Lastly, we compute an upper limit to the satellite mass loss rate due to thermal evaporation from the surface, valid if the satellite's atmosphere is thin and vapor pressure is negligible. Using this upper limit, we find that although rocky satellites around hot Jupiters with orbital periods less than a few days can be significantly evaporated in their lifetimes, detectable satellites suffer negligible mass loss at longer orbital periods.

2009-10-20

284

Identifying new opportunities for exoplanet characterisation at high spectral resolution  

CERN Document Server

[Abridged] Recently, there have been a series of detections of molecules in the atmospheres of extrasolar planets using high spectral resolution (R~100,000) observations, mostly using the CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) on the Very Large Telescope. These measurements are able to resolve molecular bands into individual absorption lines. Observing many lines simultaneously as their Doppler shift changes with time allows the detection of specific molecules in the atmosphere of the exoplanet. We performed simulations of high-resolution CRIRES observations of a planet's thermal emission and transit between 1-5 micron and performed a cross-correlation analysis on these results to assess how well the planet signal can be extracted. We also simulated day-side and night-side spectra at high spectral resolution for planets with and without a day-side temperature inversion, based on the cases of HD 189733b and HD 209458b. Several small wavelength regions in the L-band promise to yield cr...

de Kok, Remco J; Brogi, Matteo; Schwarz, Henriette; Albrecht, Simon; de Mooij, Ernst J W; Snellen, Ignas A G

2013-01-01

285

Hiding in the Shadows: Searching for Planets in Pre--transitional and Transitional Disks  

CERN Document Server

Transitional and pre--transitional disks can be explained by a number of mechanisms. This work aims to find a single observationally detectable marker that would imply a planetary origin for the gap and, therefore, indirectly indicate the presence of a young planet. N-body simulations were conducted to investigate the effect of an embedded planet of one Jupiter mass on the production of instantaneous collisional dust derived from a background planetesimal disk. Our new model allows us to predict the dust distribution and resulting observable markers with greater accuracy than previous work. Dynamical influences from a planet on a circular orbit are shown to enhance dust production in the disk interior and exterior to the planet orbit while removing planetesimals from the the orbit itself creating a clearly defined gap. In the case of an eccentric planet the gap opened by the planet is not as clear as the circular case but there is a detectable asymmetry in the dust disk.

Dobinson, Jack; Dodson-Robinson, Sarah E; Teanby, Nick A

2013-01-01

286

HIDING IN THE SHADOWS: SEARCHING FOR PLANETS IN PRE-TRANSITIONAL AND TRANSITIONAL DISKS  

International Nuclear Information System (INIS)

Transitional and pre-transitional disks can be explained by a number of mechanisms. This work aims to find a single observationally detectable marker that would imply a planetary origin for the gap and, therefore, indirectly indicate the presence of a young planet. N-body simulations were conducted to investigate the effect of an embedded planet of one Jupiter mass on the production of instantaneous collisional dust derived from a background planetesimal disk. Our new model allows us to predict the dust distribution and resulting observable markers with greater accuracy than previous works. Dynamical influences from a planet on a circular orbit are shown to enhance dust production in the disk interior and exterior to the planet orbit, while removing planetesimals from the orbit itself, creating a clearly defined gap. In the case of an eccentric planet, the gap opened by the planet is not as clear as the circular case, but there is a detectable asymmetry in the dust disk

2013-11-10

287

HIDING IN THE SHADOWS: SEARCHING FOR PLANETS IN PRE-TRANSITIONAL AND TRANSITIONAL DISKS  

Energy Technology Data Exchange (ETDEWEB)

Transitional and pre-transitional disks can be explained by a number of mechanisms. This work aims to find a single observationally detectable marker that would imply a planetary origin for the gap and, therefore, indirectly indicate the presence of a young planet. N-body simulations were conducted to investigate the effect of an embedded planet of one Jupiter mass on the production of instantaneous collisional dust derived from a background planetesimal disk. Our new model allows us to predict the dust distribution and resulting observable markers with greater accuracy than previous works. Dynamical influences from a planet on a circular orbit are shown to enhance dust production in the disk interior and exterior to the planet orbit, while removing planetesimals from the orbit itself, creating a clearly defined gap. In the case of an eccentric planet, the gap opened by the planet is not as clear as the circular case, but there is a detectable asymmetry in the dust disk.

Dobinson, Jack; Leinhardt, Zoë M. [School of Physics, H. H. Wills Physics Laboratory, University of Bristol, Bristol, BS8 1TL (United Kingdom); Dodson-Robinson, Sarah E. [Astronomy Department, University of Texas at Austin, Austin, TX 78712 (United States); Teanby, Nick A. [School of Earth Sciences, Wills Memorial Building, University of Bristol, Bristol, BS8 1RJ (United Kingdom)

2013-11-10

288

Galactic cosmic ray induced radiation dose on terrestrial exoplanets  

CERN Document Server

This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground and space based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets, falling in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in case of super earths. Such exoplanets are subjected to a high flux of Galactic Cosmic Rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin, which strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another fac...

Atri, Dimitra; Griessmeier, Jean-Mathias

2013-01-01

289

Exoplanet predictions based on the generalized Titius-Bode relation  

Science.gov (United States)

We evaluate the extent to which newly detected exoplanetary systems containing at least four planets adhere to a generalized Titius-Bode (TB) relation. We find that the majority of exoplanet systems in our sample adhere to the TB relation to a greater extent than the Solar system does, particularly those detected by the Kepler mission. We use a generalized TB relation to make a list of predictions for the existence of 141 additional exoplanets in 68 multiple-exoplanet systems: 73 candidates from interpolation, 68 candidates from extrapolation. We predict the existence of a low-radius (R < 2.5R?) exoplanet within the habitable zone of KOI-812 and that the average number of planets in the habitable zone of a star is 1-2. The usefulness of the TB relation and its validation as a tool for predicting planets will be partially tested by upcoming Kepler data releases.

Bovaird, Timothy; Lineweaver, Charles H.

2013-10-01

290

Exoplanet Habitability: Effects of Planetesimal Carbon Chemistry  

Science.gov (United States)

We explore the effects of reported differences in C/O values for exoplanet host stars on the composition of planetesimals formed beyond the snow line in these systems. Since the value of C/O in a planet forming nebula has a strong effect on amount of oxygen available for water ice in an oxidizing nebula, exoplanet systems for host stars with C/O greater than the solar value may have planetesimals with very little or no water ice. We have estimated the composition of volatile and refractory material in extrasolar planetesimals using a set of stars with a wide range of measured C/O abundances (Johnson et al. ApJ. 757(2), 192, 2012). The volatile ice content of planetesimals in these systems varies significantly with C/O, controlled primarily by the availability of O for H2O ice condensation. Systems with C/O less than the solar value (C/O = 0.55) should have very water ice rich planetesimals, while water ice mass fraction decreases rapidly with increasing C/O until only ices of CO and CO2 are left in significant proportions. If a significant fraction of C is in the form of refractory CHON particles, C and O are removed from the gas phase and the condensates for super-solar C/O values will be water-poor mixtures of silicates and metal, carbon, and carbon-bearing volatile ices, depending on temperature. For very carbon-rich systems, oxidizing conditions cannot be sustained beyond about C/O=1, due to the oxygen sequestered in solid silicates, oxides and CHON, for refractory C fractions within the Pollack et al. range of 0.4 - 0.7 (ApJ. 421, 615, 1994). These results have implications for assessing the habitability of exoplanets since they constrain the amount of water available beyond the snow line for dynamical delivery to inner planets, depending on the host star's C/O in the circumstellar nebula. Thus one the key chemical ingredients for habitability may be in short supply in carbon-rich, oxygen-poor systems even if planets exist in the 'habitable zone'. TVJ acknowledges government support at JPL/Caltech, under a contract with NASA. NM acknowledges support from Yale University. JIL was supported by the JWST Project through NASA. O.M. acknowledges support from CNES.

Johnson, Torrence; Mousis, Olivier; Lunine, Jonathan; Madhusudhan, Nikku

2014-05-01

291

Algol: An Early Candidate for a Transiting Exoplanet  

Science.gov (United States)

Virtually every astronomy text credits John Goodricke (1764-1786) with the discovery of the period of variability of the star Algol (? Per) and with the explanation of its variation (eclipses by an unseen stellar companion). Today, Algol is considered a prototype of an eclipsing binary star. In actuality, John Goodricke worked in collaboration with his neighbor, mentor, and distant relative, Edward Pigott. As observed by Hoskin1, the observing journals2 of the two clearly show that the eclipse explanation originated with Edward. Both originally used the term "planet” to describe the eclipsing body. However, in Goodricke's 1783 paper describing Algol, he writes: "....I should imagine it could hardly be accounted for otherwise than either by the interposition of a large body revolving round Algol, or some kind of motion of its own, whereby part of its body, covered with spots or such like matter...."3 Goodricke was later to soften his stance still further after the two discovered several other variable stars; his last published work4 mentions only starspots as an explanation for the light variation of Algol. Although the physics of the time would not have allowed Goodricke and Pigott to distinguish between a star and a planet as the unseen companion, the eighteenth-century astronomers showed great prescience in realizing that the eclipses of Algol were just that. Their mental leap, at a time when astronomers were just beginning to think seriously of discovering planets around other stars, should not go unremembered by modern planetary scientists. Footnotes 1 Hoskin, M. (1982). In Stellar Astronomy, Science History Publications Ltd., Chalfont St. Giles, England. 2 Goodricke and Pigott journals. York City Archives, York, England. 3 Goodricke, J. G. (1783). Phil. Soc. Roy. Soc. London 73, 474-482. 4 Goodricke, J. G. (1786). Phil. Soc. Roy. Soc. London 76, 48-61.

French, Linda M.; Stuart, I.

2008-09-01

292

Clouds and Hazes in Exoplanet Atmospheres  

CERN Document Server

Clouds and hazes are commonplace in the atmospheres of solar system planets and are likely ubiquitous in the atmospheres of extrasolar planets as well. Clouds affect every aspect of a planetary atmosphere, from the transport of radiation, to atmospheric chemistry, to dynamics and they influence - if not control - aspects such as surface temperature and habitability. In this review we aim to provide an introduction to the role and properties of clouds in exoplanetary atmospheres. We consider the role clouds play in influencing the spectra of planets as well as their habitability and detectability. We briefly summarize how clouds are treated in terrestrial climate models and consider the far simpler approaches that have been taken so far to model exoplanet clouds, the evidence for which we also review. Since clouds play a major role in the atmospheres of certain classes of brown dwarfs we briefly discuss brown dwarf cloud modeling as well. We also review how the scattering and extinction efficiencies of cloud p...

Marley, Mark S; Cuzzi, Jeffrey N; Kitzmann, Daniel

2013-01-01

293

Investigating Nearby Exoplanets via Interstellar Radar  

CERN Document Server

Interstellar radar is a potential intermediate step between passive observation of exoplanets and interstellar exploratory missions. Compared to passive observation, it has the traditional advantages of radar astronomy. It can measure surface characteristics, determine spin rates and axes, provide extremely accurate ranges, construct maps of planets, distinguish liquid from solid surfaces, find rings and moons, and penetrate clouds. It can do this even for planets close to the parent star. Compared to interstellar travel or probes, it also offers significant advantages. The technology required to build such a radar already exists, radar can return results within a human lifetime, and a single facility can investigate thousands of planetary systems. The cost, although high, is within the reach of Earth's economy, so it is cheaper as well.

Scheffer, Louis K

2013-01-01

294

Exoplanet Demographics with WFIRST-AFTA  

Science.gov (United States)

Measurements of the demographics of exoplanets over a broad range of planet and host-star properties provide fundamental empirical constraints on theories of planet formation and evolution. Because of its unique sensitivity to low-mass, long-period, and free-floating planets, microlensing is an essential complement to our arsenal of planet detection methods. I outline the expected returns of a microlensing survey with WFIRST-AFTA. When combined with the results from complementary surveys such as Kepler, WFIRST-AFTA will yield a nearly complete picture of the demographics of planetary systems throughout the Galaxy, providing fundamental tests of planet formation theories, and informing our understanding of the frequency and potential habitability of low mass planets located in the habitable zones of their host stars.

Gaudi, B. S.; WFIRST-AFTA Science Definition Team

2014-01-01

295

Doppler Imaging of Exoplanets and Brown Dwarfs  

CERN Document Server

Doppler Imaging produces 2D global maps of rotating objects using high-dispersion spectroscopy. When applied to brown dwarfs and extrasolar planets, this technique can constrain global atmospheric dynamics and/or magnetic effects on these objects in un- precedented detail. I present the first quantitative assessment of the prospects for Doppler Imaging of substellar objects with current facilities and with future giant ground-based telescopes. Observations will have the greatest sensitivity in K band, but the H and L bands will also be useful for these purposes. To assess the number and availability of targets, I also present a compilation of all measurements of photometric variability, rotation period (P), and projected rotational velocity (v sin i) for brown dwarfs and exoplanets. Several bright objects are already accessible to Doppler Imaging with currently available instruments. With the development of giant ground-based telescopes, Doppler Imaging will become feasible for many dozens of brown dwarfs and...

Crossfield, Ian J M

2014-01-01

296

Investigating nearby exoplanets via interstellar radar  

Science.gov (United States)

Interstellar radar is a potential intermediate step between passive observation of exoplanets and interstellar exploratory missions. Compared with passive observation, it has the traditional advantages of radar astronomy. It can measure surface characteristics, determine spin rates and axes, provide extremely accurate ranges, construct maps of planets, distinguish liquid from solid surfaces, find rings and moons, and penetrate clouds. It can do this even for planets close to the parent star. Compared with interstellar travel or probes, it also offers significant advantages. The technology required to build such a radar already exists, radar can return results within a human lifetime, and a single facility can investigate thousands of planetary systems. The cost, although too high for current implementation, is within the reach of Earth's economy.

Scheffer, Louis K.

2014-01-01

297

Exoplanets: light curves with different telescopes  

Science.gov (United States)

In this poster contribution we present photometric results of the exoplanet WASP-1b with different filters in the 80 cm IAC80 telescope at the Observatorio del Teide (Canary Islands, Spain), as part of an observation campaign of the Robotic Telescopes Group at Centro de Astrobiologia (CAB) in October 2008. After that, we compare the previous light curves with the ones obtained by our group using the INTA-CAB 50 cm robotic telescope located at Calar Alto Observatory (Almeria, Spain). We indicate the photometric accuracy obtained for each case (2 mmag in the first case and 3 mmag in the second one). Finally, we point out how the studies carried out by our robotic telescope can/must be complemented with the use of other astronomical facilities.

Ullan, A.; Eibe, M. T.; Cuesta, L.; Perez-Verde, A.; Navas, J.

2011-11-01

298

The Galactic Exoplanet Survey Telescope (GEST)  

CERN Document Server

The Galactic Exoplanet Survey Telescope (GEST) will observe a 2 square degree field in the Galactic bulge to search for extra-solar planets using a gravitational lensing technique. This gravitational lensing technique is the only method employing currently available technology that can detect Earth-mass planets at high signal-to-noise, and can measure the frequency of terrestrial planets as a function of Galactic position. GEST's sensitivity extends down to the mass of Mars, and it can detect hundreds of terrestrial planets with semi-major axes ranging from 0.7 AU to infinity. GEST will be the first truly comprehensive survey of the Galaxy for planets like those in our own Solar System.

Bennett, D P; Bond, I; Cheng, E; Cook, K; Deming, D; Garnavich, P M; Griest, K; Jewitt, D; Kaiser, N; Lauer, T R; Lunine, J; Luppino, G; Mather, J; Minniti, D; Peale, S; Rhie, S; Rhodes, J; Schneider, J; Sonneborn, G; Stevenson, R; Stubbs, C; Tenerelli, D; Woolf, N; Yock, P C M

2002-01-01

299

Habitable exoplanets statistics in the Milky Way  

Science.gov (United States)

We present an exoplanet statistical analysis into the Milky Way. We use the Becanson galactic synthetic model to simulate the Milky Way and the galactic and stellar habitable zones to calculate habitable planets. To assess habitability on the Galactic scale, we model supernova rates and planet formation. Our study, models the SNII and SNIa sterilizations by selecting them from within this preexisting stellar population. Furthermore, we consider habitability on tidally locked and non-tidally locked planets separately, and study habitability as a function of height above and below the Galactic mid-plane. The number of total habitable planets makes Milky Way practically empty of habitable planets. Our results, from these simulations, agree very well with Kepler's discoveries. Finally, we apply our results to the PLATO future space mission.

Anagnos, Th.

2013-09-01

300

EChO - Exoplanet Characterisation Observatory  

CERN Document Server

A dedicated mission to investigate exoplanetary atmospheres represents a major milestone in our quest to understand our place in the universe by placing our Solar System in context and by addressing the suitability of planets for the presence of life. EChO -the Exoplanet Characterisation Observatory- is a mission concept specifically geared for this purpose. EChO will provide simultaneous, multi-wavelength spectroscopic observations on a stable platform that will allow very long exposures. EChO will build on observations by Hubble, Spitzer and groundbased telescopes, which discovered the first molecules and atoms in exoplanetary atmospheres. EChO will simultaneously observe a broad enough spectral region -from the visible to the mid-IR- to constrain from one single spectrum the temperature structure of the atmosphere and the abundances of the major molecular species. The spectral range and resolution are tailored to separate bands belonging to up to 30 molecules to retrieve the composition and temperature str...

Tinetti, G; Henning, T; Meyer, M; Micela, G; Ribas, I; Stam, D; Swain, M; Krause, O; Ollivier, M; Pace, E; Swinyard, B; Aylward, A; van Boekel, R; Coradini, A; Encrenaz, T; Snellen, I; Zapatero-Osorio, M R; Bouwman, J; Cho, J Y-K; Foresto, V Coudé du; Guillot, T; Lopez-Morales, M; Mueller-Wodarg, I; Palle, E; Selsis, F; Sozzetti, A; Ade, P A R; Achilleos, N; Adriani, A; Agnor, C B; Afonso, C; Prieto, C Allende; Bakos, G; Barber, R J; Barlow, M; Bernath, P; Bezard, B; Bordé, P; Brown, L R; Cassan, A; Cavarroc, C; Ciaravella, A; Cockell, C O U; Coustenis, A; Danielski, C; Decin, L; De Kok, R; Demangeon, O; Deroo, P; Doel, P; Drossart, P; Fletcher, L N; Focardi, M; Forget, F; Fossey, S; Fouqué, P; Frith, J; Galand, M; Gaulme, P; Hernández, J I González; Grasset, O; Grassi, D; Grenfell, J L; Griffin, M J; Griffith, C A; Grözinger, U; Guedel, M; Guio, P; Hainaut, O; Hargreaves, R; Hauschildt, P H; Heng, K; Heyrovsky, D; Hueso, R; Irwin, P; Kaltenegger, L; Kervella, P; Kipping, D; Koskinen, T T; Kovács, G; La Barbera, A; Lammer, H; Lellouch, E; Leto, G; Morales, M Lopez; Valverde, M A Lopez; Lopez-Puertas, M; Lovis, C; Maggio, A; Maillard, J P; Prado, J Maldonado; Marquette, J B; Martin-Torres, F J; Maxted, P; Miller, S; Molinari, S; Montes, D; Moro-Martin, A; Moses, J I; Mousis, O; Tuong, N Nguyen; Nelson, R; Orton, G S; Pantin, E; Pascale, E; Pezzuto, S; Pinfield, D; Poretti, E; Prinja, R; Prisinzano, L; Rees, J M; Reiners, A; Samuel, B; Sanchez-Lavega, A; Forcada, J Sanz; Sasselov, D; Savini, G; Sicardy, B; Smith, A; Stixrude, L; Strazzulla, G; Tennyson, J; Tessenyi, M; Vasisht, G; Vinatier, S; Viti, S; Waldmann, I; White, G J; Widemann, T; Wordsworth, R; Yelle, R; Yung, Y; Yurchenko, S N

2011-01-01

 
 
 
 
301

Climate instability on tidally locked exoplanets  

CERN Multimedia

Feedbacks that can destabilize the climates of synchronously-rotating rocky planets may arise on planets with strong day-night surface temperature contrasts. Earth-like habitable-zone (HZ) planets maintain stable surface liquid water over geological time. This requires equilibrium between the temperature-dependent rate of greenhouse-gas consumption by weathering,and greenhouse-gas resupply by other processes. Detected small-radius exoplanets, and anticipated M-dwarf HZ rocky planets, are expected to be tidally locked. We investigate two feedbacks that can destabilize climate on tidally-locked planets. (1) If small changes in pressure alter the temperature distribution across a planet's surface such that the weathering rate increases when the pressure decreases, a positive feedback occurs involving increasing weathering rate near the substellar point, decreasing pressure, and increasing substellar surface temperature. (2) When decreases in pressure increase the surface area above the melting point (through red...

Kite, Edwin S; Manga, Michael

2011-01-01

302

MOLECULAR-KINETIC SIMULATIONS OF ESCAPE FROM THE EX-PLANET AND EXOPLANETS: CRITERION FOR TRANSONIC FLOW  

Energy Technology Data Exchange (ETDEWEB)

The equations of gas dynamics are extensively used to describe atmospheric loss from solar system bodies and exoplanets even though the boundary conditions at infinity are not uniquely defined. Using molecular-kinetic simulations that correctly treat the transition from the continuum to the rarefied region, we confirm that the energy-limited escape approximation is valid when adiabatic expansion is the dominant cooling process. However, this does not imply that the outflow goes sonic. Rather large escape rates and concomitant adiabatic cooling can produce atmospheres with subsonic flow that are highly extended. Since this affects the heating rate of the upper atmosphere and the interaction with external fields and plasmas, we give a criterion for estimating when the outflow goes transonic in the continuum region. This is applied to early terrestrial atmospheres, exoplanet atmospheres, and the atmosphere of the ex-planet, Pluto, all of which have large escape rates.

Johnson, Robert E.; Volkov, Alexey N.; Erwin, Justin T. [Engineering Physics, University of Virginia, Charlottesville, VA 22904-4745 (United States)

2013-05-01

303

Molecular-Kinetic Simulations of Escape from the Ex-planet and Exoplanets: Criterion for Transonic Flow  

CERN Document Server

The equations of gas dynamics are extensively used to describe atmospheric loss from solar system bodies and exoplanets even though the boundary conditions at infinity are not uniquely defined. Using molecular-kinetic simulations that correctly treat the transition from the continuum to the rarefied region, we confirm that the energy-limited escape approximation is valid when adiabatic expansion is the dominant cooling process. However, this does not imply that the outflow goes sonic. Rather large escape rates and concomitant adiabatic cooling can produce atmospheres with subsonic flow that are highly extended. Since this affects the heating rate of the upper atmosphere and the interaction with external fields and plasmas, we give a criterion for estimating when the outflow goes transonic in the continuum region. This is applied to early terrestrial atmospheres, exoplanet atmospheres, and the atmosphere of the ex-planet, Pluto, all of which have large escape rates.

Johnson, Robert E; Erwin, Justin T

2013-01-01

304

An integrated payload design for the Exoplanet Characterisation Observatory (EChO)  

DEFF Research Database (Denmark)

The Exoplanet Characterisation Observatory (EChO) is a space mission dedicated to undertaking spectroscopy of transiting exoplanets over the widest wavelength range possible. It is based around a highly stable space platform with a 1.2 m class telescope. The mission is currently being studied by ESA in the context of a medium class mission within the Cosmic Vision programme for launch post 2020. The payload suite is required to provide simultaneous coverage from the visible to the mid-infrared and must be highly stable and effectively operate as a single instrument. In this paper we describe the integrated spectrometer payload design for EChO which will cover the 0.4 to 16 micron wavelength band. The instrumentation is subdivided into 5 channels (Visible/Near Infrared, Short Wave InfraRed, 2 x Mid Wave InfraRed; Long Wave InfraRed) with a common set of optics spectrally dividing the input beam via dichroics. We discuss the significant design issues for the payload and the detailed technical trade-offs that weare undertaking to produce a payload for EChO that can be built within the mission and programme constraints and yet which will meet the exacting scientific performance required to undertake transit spectroscopy. © 2012 SPIE.

Swinyard, Bruce; Tinetti, Giovanna

2012-01-01

305

CHEOPS: A Transit Photometry Mission for ESA's Small Mission Programme  

CERN Document Server

Ground based radial velocity (RV) searches continue to discover exoplanets below Neptune mass down to Earth mass. Furthermore, ground based transit searches now reach milli-mag photometric precision and can discover Neptune size planets around bright stars. These searches will find exoplanets around bright stars anywhere on the sky, their discoveries representing prime science targets for further study due to the proximity and brightness of their host stars. A mission for transit follow-up measurements of these prime targets is currently lacking. The first ESA S-class mission CHEOPS (CHaracterizing ExoPlanet Satellite) will fill this gap. It will perform ultra-high precision photometric monitoring of selected bright target stars almost anywhere on the sky with sufficient precision to detect Earth sized transits. It will be able to detect transits of RV-planets by photometric monitoring if the geometric configuration results in a transit. For Hot Neptunes discovered from the ground, CHEOPS will be able to impr...

Broeg, C; Ehrenreich, D; Alibert, Y; Baumjohann, W; Benz, W; Deleuil, M; Gillon, M; Ivanov, A; Liseau, R; Meyer, M; Oloffson, G; Pagano, I; Piotto, G; Pollacco, D; Queloz, D; Ragazzoni, R; Renotte, E; Steller, M; Thomas, N

2013-01-01

306

New National Telescope at La Silla - TRAPPIST to Scout the Sky and Uncover Exoplanets and Comets  

Science.gov (United States)

A new robotic telescope has had first light at ESO's La Silla Observatory, in Chile. TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) is devoted to the study of planetary systems through two approaches: the detection and characterisation of planets located outside the Solar System (exoplanets) and the study of comets orbiting around the Sun. The 60-cm telescope is operated from a control room in Liège, Belgium, 12 000 km away. "The two themes of the TRAPPIST project are important parts of an emerging interdisciplinary field of research - astrobiology - that aims at studying the origin and distribution of life in the Universe," explains Michaël Gillon, who is in charge of the exoplanet studies. "Terrestrial planets similar to our Earth are obvious targets for the search for life outside the Solar System, while comets are suspected to have played an important role in the appearance and development of life on our planet," adds his colleague Emmanuël Jehin, who leads the cometary part of the project. TRAPPIST will detect and characterise exoplanets by making high precision measurements of "brightness dips" that might possibly be caused by exoplanet transits. During such a transit, the observed brightness of the star decreases slightly because the planet blocks a part of the starlight. The larger the planet, the more of the light is blocked and the more the brightness of the star will decrease [1]. "ESO's La Silla Observatory on the outskirts of the Atacama Desert is certainly one of the best astronomical sites in the world," says Gillon. "And because it is already home to two superb exoplanet hunters, we couldn't have found a better place to install our robotic telescope." The astronomers behind the TRAPPIST initiative will work very closely with the teams using HARPS on the 3.6-metre telescope and CORALIE attached to the Swiss 1.2-metre Leonhard Euler Telescope, both at La Silla. TRAPPIST is a collaboration between the University of Liège and the Geneva Observatory, Switzerland. The telescope is installed in the building that housed the old Swiss T70 telescope. Thanks to this collaboration, the whole project is on a fast track: it took only two years between taking the decision to build and first light. TRAPPIST will also be used for the study of southern comets. To this aim, the telescope is equipped with special large, high quality cometary filters, allowing astronomers to study regularly and in detail the ejection of several types of molecules by comets during their journey around the Sun. "With dozens of comets observed each year, this will provide us with a unique dataset, bringing important information about their nature," says Jehin. TRAPPIST is a lightweight 0.6-metre robotic telescope, fully automated and moving precisely across the sky at a high speed. The observing programme is prepared in advance and the telescope can perform a full night of observations unattended. A meteorological station monitors the weather continuously and decides to close the dome if necessary. Notes [1] A planetary transit occurs when a celestial body passes in front of its host star and blocks some of the star's light. This type of eclipse causes changes in the apparent brightness of the star and enables the planet's diameter to be measured. Combined with radial velocity measurements, it is also possible to deduce the mass and, hence, the density of the planet. More information TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) is a project led by the Department of Astrophysics, Geophysics and Oceanography (AGO) of the University of Liège (Belgium), in close collaboration with the Observatory of Geneva (Switzerland). TRAPPIST is mostly funded by the Belgian Fund for Scientific Research (FNRS) with the participation of the Swiss National Science Foundation (SNF). The team is composed of Emmanuël Jehin, Michaël Gillon, Pierre Magain, Virginie Chantry, Jean Manfroid, and Damien Hutsemékers (University of Liège, Belgium) and Didier Queloz and St

2010-06-01

307

What asteroseismology can do for exoplanets: Kepler-410A b is a Small Neptune around a bright star, in an eccentric orbit consistent with low obliquity  

DEFF Research Database (Denmark)

We confirm the Kepler planet candidate Kepler-410b (KOI-42b) as a Neptune sized exoplanet on a 17.8 day, eccentric orbit around the bright (Kp = 9.4) star Kepler-410A. This is the third brightest confirmed planet host star in the Kepler field and one of the brightest hosts of all currently known transiting exoplanets. Kepler-410 consists of a blend between the fast rotating planet host star (Kepler-410A) and a fainter star (Kepler-410B), which has complicated the confirmation of the planetary candidate. Employing asteroseismology, using constraints from the transit light curve, adaptive optics and speckle images, and Spitzer transit observations, we demonstrate that the candidate can only be an exoplanet orbiting Kepler-410A. Via asteroseismology we determine the following stellar and planetary parameters with high precision; M$_\\star = 1.214 \\pm 0.033$ M$_\\odot$, R$_\\star = 1.352 \\pm 0.010$ R$_\\odot$, Age = $2.76 \\pm 0.54$ Gyr, planetary radius ($2.838 \\pm 0.054$ R$_\\oplus$), and orbital eccentricity ($0.17^{+0.07}_{-0.06}$). In addition, rotational splitting of the pulsation modes allows for a measurement of Kepler-410A's inclination and rotation rate. Our measurement of an inclination of $82.5^{+7.5}_{-2.5}$ [$^\\circ$] indicates a low obliquity in this system. Transit timing variations indicate the presence of at least one additional (non-transiting) planet in the system.

Van Eylen, Vincent; Lund, Mikkel N.

2014-01-01

308

CARBON AND OXYGEN ABUNDANCES IN THE HOT JUPITER EXOPLANET HOST STAR XO-2B AND ITS BINARY COMPANION  

Energy Technology Data Exchange (ETDEWEB)

With the aim of connecting the compositions of stars and planets, we present the abundances of carbon and oxygen, as well as iron and nickel, for the transiting exoplanet host star XO-2N and its wide-separation binary companion XO-2S. Stellar parameters are derived from high-resolution, high signal-to-noise spectra, and the two stars are found to be similar in their T{sub eff}, log g, iron ([Fe/H]), and nickel ([Ni/H]) abundances. Their carbon ([C/H]) and oxygen ([O/H]) abundances also overlap within errors, although XO-2N may be slightly more C-rich and O-rich than XO-2S. The C/O ratios of both stars ({approx}0.60 {+-} 0.20) may also be somewhat larger than solar (C/O {approx} 0.50). The XO-2 system has a transiting hot Jupiter orbiting one binary component but not the other, allowing us to probe the potential effects planet formation might have on the host star composition. Additionally, with multiple observations of its atmosphere the transiting exoplanet XO-2b lends itself to compositional analysis, which can be compared to the natal chemical environment established by our binary star elemental abundances. This work sets the stage for determining how similar or different exoplanet and host star compositions are, and the implications for planet formation, by discussing the C/O ratio measurements in the unique environment of a visual binary system with one star hosting a transiting hot Jupiter.

Teske, Johanna K. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Schuler, Simon C. [University of Tampa, 401 W. Kennedy Blvd., Tampa, FL 33606 (United States); Cunha, Katia [Observatorio Nacional, Rua General Jose Cristino, 77, 20921-400, Sao Cristovao, Rio de Janeiro, RJ (Brazil); Smith, Verne V. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Griffith, Caitlin A., E-mail: jteske@as.arizona.edu [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

2013-05-01

309

MODELING MULTI-WAVELENGTH STELLAR ASTROMETRY. III. DETERMINATION OF THE ABSOLUTE MASSES OF EXOPLANETS AND THEIR HOST STARS  

Energy Technology Data Exchange (ETDEWEB)

Astrometric measurements of stellar systems are becoming significantly more precise and common, with many ground- and space-based instruments and missions approaching 1 {mu}as precision. We examine the multi-wavelength astrometric orbits of exoplanetary systems via both analytical formulae and numerical modeling. Exoplanets have a combination of reflected and thermally emitted light that causes the photocenter of the system to shift increasingly farther away from the host star with increasing wavelength. We find that, if observed at long enough wavelengths, the planet can dominate the astrometric motion of the system, and thus it is possible to directly measure the orbits of both the planet and star, and thus directly determine the physical masses of the star and planet, using multi-wavelength astrometry. In general, this technique works best for, though is certainly not limited to, systems that have large, high-mass stars and large, low-mass planets, which is a unique parameter space not covered by other exoplanet characterization techniques. Exoplanets that happen to transit their host star present unique cases where the physical radii of the planet and star can be directly determined via astrometry alone. Planetary albedos and day-night contrast ratios may also be probed via this technique due to the unique signature they impart on the observed astrometric orbits. We develop a tool to examine the prospects for near-term detection of this effect, and give examples of some exoplanets that appear to be good targets for detection in the K to N infrared observing bands, if the required precision can be achieved.

Coughlin, J. L. [Department of Astronomy, New Mexico State University, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States); Lopez-Morales, Mercedes, E-mail: jlcough@nmsu.edu [Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB, Facultat de Ciencies, Torre C5, parell, 2a pl, E-08193 Bellaterra, Barcelona (Spain)

2012-05-10

310

ESPRESSO: The next European exoplanet hunter  

CERN Document Server

The acronym ESPRESSO stems for Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations; this instrument will be the next VLT high resolution spectrograph. The spectrograph will be installed at the Combined-Coud\\'e Laboratory of the VLT and linked to the four 8.2 m Unit Telescopes (UT) through four optical Coud\\'e trains. ESPRESSO will combine efficiency and extreme spectroscopic precision. ESPRESSO is foreseen to achieve a gain of two magnitudes with respect to its predecessor HARPS, and to improve the instrumental radial-velocity precision to reach the 10 cm/s level. It can be operated either with a single UT or with up to four UTs, enabling an additional gain in the latter mode. The incoherent combination of four telescopes and the extreme precision requirements called for many innovative design solutions while ensuring the technical heritage of the successful HARPS experience. ESPRESSO will allow to explore new frontiers in most domains of astrophysics that require precision and sen...

Pepe, F; Cristiani, S; Rebolo, R; Santos, N C; Dekker, H; Mégevand, D; Zerbi, F M; Cabral, A; Di Marcantonio, P; Abreu, M; Affolter, M; Aliverti, M; Prieto, C Allende; Amate, M; Avila, G; Baldini, V; Bristow, P; Broeg, C; Cirami, R; Coelho, J; Conconi, P; Coretti, I; Cupani, G; D'Odorico, V; De Caprio, V; Delabre, B; Dorn, R; Figueira, P; Fragoso, A; Galeotta, S; Genolet, L; Gomes, R; Hernández, J I González; Hughes, I; Iwert, O; Kerber, F; Landoni, M; Lizon, J -L; Lovis, C; Maire, C; Mannetta, M; Martins, C; Monteiro, M; Oliveira, A; Poretti, E; Rasilla, J L; Riva, M; Tschudi, S Santana; Santos, P; Sosnowska, D; Sousa, S; Spanó, P; Tenegi, F; Toso, G; Vanzella, E; Viel, M; Osorio, M R Zapatero

2014-01-01

311

Thermodynamic Limits on Magnetodynamos in Rocky Exoplanets  

CERN Document Server

To ascertain whether magnetic dynamos operate in rocky exoplanets more massive or hotter than the Earth, we developed a parametric model of a differentiated rocky planet and its thermal evolution. Our model reproduces the established properties of Earth's interior and magnetic field at the present time. When applied to Venus, assuming that planet lacks plate tectonics and has a dehydrated mantle with an elevated viscosity, the model shows that the dynamo shuts down or never operated. Our model predicts that at a fixed planet mass, dynamo history is sensitive to core size, but not to the initial inventory of long-lived, heat-producing radionuclides. It predicts that rocky planets larger than 2.5 Earth masses will not develop inner cores because the temperature-pressure slope of the iron solidus becomes flatter than that of the core adiabat. Instead, iron "snow" will condense near or at the top of these cores, and the net transfer of latent heat upwards will suppress convection and a dynamo. More massive planet...

Gaidos, Eric; Manga, Michael; Hernlund, John

2010-01-01

312

Simulations of Exoplanet Microlensing Observations by WFIRST  

Science.gov (United States)

One of the primary goals of the WFIRST mission is to conduct a time-series survey of the Galactic bulge to detect and characterize exoplanetary microlensing events. For two months at a time, over the mission lifetime, WFIRST will continuously monitor ~100 million stars every 15 minutes in order to detect the short-lived signatures of low-mass planets. WFIRST will be sensitive to planets with masses down to Mars-mass, in orbits from ~1AU outwards. Using the newly developed MaBuLS microlensing simulator, we explore the sensitivity of the WFIRST microlensing survey to planets over a wide range of masses and orbital sizes, and how the sensitivity is affected by various design choices being considered by the WFIRST science definition teams. Over all designs being considered, WFIRST can be expected to detect thousands of planets, including several hundred of Earth-mass and below. These planets, in orbits inaccessible to other techniques, will complete the census of exoplanets begun by Kepler, building a comprehensive picture of the end results of the planet formation process.

Penny, Matthew; Gaudi, B. S.; Robin, A.

2013-01-01

313

Starshades for Exoplanet Imaging and Characterization  

Science.gov (United States)

An external occulter is a satellite employing a large screen, or starshade, that flies in formation with a spaceborne telescope to provide the starlight suppression needed for detecting and characterizing exoplanets. Among the advantages of using an occulter are the broadband allowed for characterization and the removal of light before entering the observatory, greatly relaxing the requirements on the telescope and instrument. In this presentation I will explain how star shades achieve high contrast through precise design and control of their shape and how we develop an error budget to establish requirements on the manufacturing and control. Raising the technology readiness level of starshades requires a sequence of activities to verify approaches to manufacturing, deployment, test, and analysis. The SAT-TDEM program has been instrumental in raising the readiness level of the most critical technology. In particular, I will show the results of our first TDEM in 2010-2012 that verified a full scale petal could be built and measured to the needed accuracy for 10 orders of magnitude of contrast. Our second TDEM in 2012-2014 verified that a starshade could be deployed and the petals could be placed to the required position to better than 1 mm. Finally, laboratory experiments have verified the optical modeling used to predict starshade performance to better than 1e-10.

Kasdin, N. J.; Vanderbei, R. J.; Shaklan, S.; Lisman, D.; Thomson, M.; Cady, E.; Macintosh, B.; Sirbu, D.; Lo, A.

2014-01-01

314

Direct imaging of exoplanets in the habitable zone with adaptive optics  

CERN Document Server

One of the primary goals of exoplanet science is to find and characterize habitable planets, and direct imaging will play a key role in this effort. Though imaging a true Earth analog is likely out of reach from the ground, the coming generation of giant telescopes will find and characterize many planets in and near the habitable zones (HZs) of nearby stars. Radial velocity and transit searches indicate that such planets are common, but imaging them will require achieving extreme contrasts at very small angular separations, posing many challenges for adaptive optics (AO) system design. Giant planets in the HZ may even be within reach with the latest generation of high-contrast imagers for a handful of very nearby stars. Here we will review the definition of the HZ, and the characteristics of detectable planets there. We then review some of the ways that direct imaging in the HZ will be different from the typical exoplanet imaging survey today. Finally, we present preliminary results from our observations of t...

Males, Jared R; Guyon, Olivier; Morzinski, Katie M; Puglisi, Alfio; Hinz, Philip; Follette, Katherine B; Monnier, John D; Tolls, Volker; Rodigas, Timothy J; Weinberger, Alycia; Boss, Alan; Kopon, Derek; Wu, Ya-lin; Esposito, Simone; Riccardi, Armando; Xompero, Marco; Briguglio, Runa; Pinna, Enrico

2014-01-01

315

A Search for Additional Planets in the NASA EPOXI Observations of the Exoplanet System GJ 436  

CERN Document Server

We present time series photometry of the M dwarf transiting exoplanet system GJ 436 obtained with the the EPOCh (Extrasolar Planet Observation and Characterization) component of the NASA EPOXI mission. We conduct a search of the high-precision time series for additional planets around GJ 436, which could be revealed either directly through their photometric transits, or indirectly through the variations these second planets induce on the transits of the previously known planet. In the case of GJ 436, the presence of a second planet is perhaps indicated by the residual orbital eccentricity of the known hot Neptune companion. We find no candidate transits with significance higher than our detection limit. From Monte Carlo tests of the time series, we rule out transiting planets larger than 1.0 R_Earth interior to GJ 436b with 95% confidence. Assuming coplanarity of additional planets with the orbit of GJ 436b, we cannot expect that putative planets with orbital periods longer than about 3.4 days will transit. H...

Ballard, Sarah; Charbonneau, David; Deming, Drake; Holman, Matthew J; Fabrycky, Daniel; A'Hearn, Michael F; Wellnitz, Dennis D; Barry, Richard K; Kuchner, Marc J; Livengood, Timothy A; Hewagama, Tilak; Sunshine, Jessica M; Hampton, Don L; Lisse, Carey M; Seager, Sara; Veverka, Joseph F

2009-01-01

316

PULSE: The Palomar Ultraviolet Laser for the Study of Exoplanets  

CERN Document Server

The Palomar Ultraviolet Laser for the Study of Exoplanets (PULSE) will dramatically expand the science reach of PALM-3000, the facility high-contrast extreme adaptive optics system on the 5-meter Hale Telescope. By using an ultraviolet laser to measure the dominant high spatial and temporal order turbulence near the telescope aperture, one can increase the limiting natural guide star magnitude for exquisite correction from mV < 10 to mV < 16. Providing the highest near-infrared Strehl ratios from any large telescope laser adaptive optics system, PULSE uniquely enables spectroscopy of low-mass and more distant young exoplanet systems, essential to formulating a complete picture of exoplanet populations.

Baranec, Christoph; Burruss, Rick S; Bowler, Brendan P; van Dam, Marcos; Riddle, Reed; Shelton, J Christopher; Truong, Tuan; Roberts, Jennifer; Milburn, Jennifer; Tesch, Jonathan

2014-01-01

317

Adaptive Optics Observations of Exoplanets, Brown Dwarfs, & Binary Stars  

CERN Document Server

The current direct observations of brown dwarfs and exoplanets have been obtained using instruments not specifically designed for overcoming the large contrast ratio between the host star and any wide-separation faint companions. However, we are about to witness the birth of several new dedicated observing platforms specifically geared towards high contrast imaging of these objects. The Gemini Planet Imager, VLT-SPHERE, Subaru HiCIAO, and Project 1640 at the Palomar 5m telescope will return images of numerous exoplanets and brown dwarfs over hundreds of observing nights in the next five years. Along with diffraction-limited coronagraphs and high-order adaptive optics, these instruments also will return spectral and polarimetric information on any discovered targets, giving clues to their atmospheric compositions and characteristics. Such spectral characterization will be key to forming a detailed theory of comparative exoplanetary science which will be widely applicable to both exoplanets and brown dwarfs. Fu...

Hinkley, Sasha

2011-01-01

318

Surveying Nearby M dwarfs with Gaia: A Treasure Trove for Exoplanet Astrophysics  

Science.gov (United States)

Cool, nearby M dwarfs within a few tens of parsecs from the Sun are today becoming the focus of dedicated experiments in the realm of exoplanets astrophysics. This is due to the shift in theoretical paradigms in light of new observations, and thanks to the improved understanding of the observational opportunities for planet detection and characterization provided by this sample. Gaia, in its all-sky survey, will deliver precision astrometry for a magnitude-limited (V=20) sample of M dwarfs in the vicinity of the Sun, providing an inventory of cool nearby stars with a much higher degree of completeness (particularly for late sub-types) with respect to currently available catalogs. We gauge the Gaia potential for precision astrometry of exoplanets orbiting a sample of actual M stars within 30 pc from the Sun. The stellar reservoir is carefully selected based on cross-correlation among catalogs in the literature (e.g., Lepine, PMSU).We express Gaia sensitivity thresholds as a function of system parameters and in view of the latest mission profile, including the most up-to-date astrometric error model. The simulations also provide insight on the capability of high-precision astrometry to reconstruct the underlying orbital elements and mass distributions of the generated companions. We investigate the synergy between the Gaia data on nearby M dwarfs and other ground-based and spaceborne programs for planet detection and characterization, with a particular focus on: a) the improvements in the determination of transiting planet parameters thanks to the exquisitely precise stellar distances determined by Gaia; b) the betterment in orbit modeling when Gaia astrometry and precision radial-velocities are available for the same targets; and c) the ability of Gaia to carefully predict the ephemerides of detected (transiting and non-transiting) planets aroundM stars, for the purpose of spectroscopic characterization of their atmospheres with dedicated observatories in space, such as EChO.

Sozzetti, A.; Tinetti, G.; Lattanzi, M. G.; Micela, G.; Morbidelli, R.; Giacobbe, P.

2011-10-01

319

The Gaia Astrometric Survey of Nearby M Dwarfs: A Treasure Trove for Exoplanet Astrophysics  

Science.gov (United States)

Cool, nearby M dwarfs within a few tens of parsecs from the Sun are becoming the focus of dedicated experiments in the realm of exoplanets astrophysics. This is due to the shift in theoretical paradigms in light of new observations, and to the improved understanding of the observational opportunities for planet detection and characterization provided by this sample. Gaia, in its all-sky survey, will deliver precision astrometry for a magnitude-limited (V=20) sample of M dwarfs, providing an inventory of cool nearby stars with a much higher degree of completeness (particularly for late sub-types) with respect to currently available catalogs. We gauge the Gaia potential for precision astrometry of exoplanets orbiting a sample of already known dM stars within 30 pc from the Sun, carefully selected based on cross-correlation among catalogs in the literature (e.g., Lepine, PMSU). We express Gaia sensitivity thresholds as a function of system parameters and in view of the latest mission profile, including the most up-to-date astrometric error model. The simulations also provide insight on the capability of high-precision astrometry to reconstruct the underlying orbital elements and mass distributions of the generated companions. These results will help in evaluating the complete expected Gaia planet population around late-type stars. We investigate the synergy between the Gaia data on nearby M dwarfs and other ground-based and space-borne programs for planet detection and characterization, with a particular focus on: a) the improvements in the determination of transiting planet parameters thanks to the exquisitely precise stellar distances determined by Gaia; b) the betterment in orbit modeling when Gaia astrometry and precision radial-velocities are available for the same targets; and c) the ability of Gaia to carefully predict the ephemerides of (transiting and non-transiting) planets around M stars, for spectroscopic characterization of their atmospheres with dedicated observatories in space, such as EChO.

Sozzetti, Alessandro; Giacobbe, P.; Lattanzi, M. G.; Micela, G.; Tinetti, G.

2011-09-01

320

Exoplanet discoveries with the CoRoT space observatory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The CoRoT space observatory is a project which is led by the French space agency CNES and leading space research institutes in Austria, Brazil, Belgium, Germany and Spain and also the European Space Agency ESA. CoRoT observed since its launch in December 27, 2006 about 100 000 stars for the exoplanet channel, during 150 days uninterrupted high-precision photometry. Since the The CoRoT-team has several exoplanet candidates which are currently analyzed under its study, we report here the discov...

2010-01-01

 
 
 
 
321

Kepler Exoplanet Candidate Host Stars are Preferentially Metal Rich  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We find that Kepler exoplanet candidate (EC) host stars are preferentially metal-rich, including the low-mass stellar hosts of small-radius ECs. The last observation confirms a tentative hint that there is a correlation between the metallicity of low-mass stars and the presence of low-mass and small-radius exoplanets. In particular, we compare the J-H--g-r color-color distribution of Kepler EC host stars with a control sample of dwarf stars selected from the ~150,000 stars o...

Schlaufman, Kevin C.; Laughlin, Gregory

2011-01-01

322

THERMODYNAMIC LIMITS ON MAGNETODYNAMOS IN ROCKY EXOPLANETS  

International Nuclear Information System (INIS)

To ascertain whether magnetic dynamos operate in rocky exoplanets more massive or hotter than the Earth, we developed a parametric model of a differentiated rocky planet and its thermal evolution. Our model reproduces the established properties of Earth's interior and magnetic field at the present time. When applied to Venus, assuming that planet lacks plate tectonics and has a dehydrated mantle with an elevated viscosity, the model shows that the dynamo shuts down or never operated. Our model predicts that at a fixed planet mass, dynamo history is sensitive to core size, but not to the initial inventory of long-lived, heat-producing radionuclides. It predicts that rocky planets larger than 2.5 Earth masses will not develop inner cores because the temperature-pressure slope of the iron solidus becomes flatter than that of the core adiabat. Instead, iron 'snow' will condense near or at the top of these cores, and the net transfer of latent heat upward will suppress convection and a dynamo. More massive planets can have anemic dynamos due to core cooling, but only if they have mobile lids (plate tectonics). The lifetime of these dynamos is shorter with increasing planet mass but longer with higher surface temperature. Massive Venus-like planets with stagnant lids and more viscous mantles will lack dynamos altogether. We identify two alternative sources of magnetic fields on rocky planets: eddy currents induced in the hot or molten upper layers of planets on very short-period orbits, and dynamos in the ionic conducting layers of 'ocean' planets with ?10% mass in an upper mantle of water (ice).

2010-08-01

323

Exoplanet atmospheres with EChO: spectral retrievals using EChOSim  

Science.gov (United States)

We demonstrate the effectiveness of the Exoplanet Characterisation Observatory mission concept for constraining the atmospheric properties of hot and warm gas giants and super Earths. Synthetic primary and secondary transit spectra for a range of planets are passed through EChOSim [13] to obtain the expected level of noise for different observational scenarios; these are then used as inputs for the NEMESIS atmospheric retrieval code and the retrieved atmospheric properties (temperature structure, composition and cloud properties) compared with the known input values, following the method of [1]. To correctly retrieve the temperature structure and composition of the atmosphere to within 2 ?, we find that we require: a single transit or eclipse of a hot Jupiter orbiting a sun-like (G2) star at 35 pc to constrain the terminator and dayside atmospheres; 20 transits or eclipses of a warm Jupiter orbiting a similar star; 10 transits/eclipses of a hot Neptune orbiting an M dwarf at 6 pc; and 30 transits or eclipses of a GJ1214b-like planet.

Barstow, Joanna K.; Bowles, Neil E.; Aigrain, Suzanne; Fletcher, Leigh N.; Irwin, Patrick G. J.; Varley, Ryan; Pascale, Enzo

2014-06-01

324

TrES Exoplanets and False Positives: Finding the Needle in the Haystack  

CERN Document Server

Our incomplete understanding of the formation of gas giants and of their mass-radius relationship has motivated ground-based, wide-field surveys for new transiting extrasolar giant planets. Yet, astrophysical false positives have dominated the yield from these campaigns. Astronomical systems where the light from a faint eclipsing binary and a bright star is blended, producing a transit-like light curve, are particularly difficult to eliminate. As part of the Trans-atlantic Exoplanet Survey, we have encountered numerous false positives and have developed a procedure to reject them. We present examples of these false positives, including the blended system GSC 03885-00829 which we showed to be a K dwarf binary system superimposed on a late F dwarf star. This transit candidate in particular demonstrates the careful analysis required to identify astrophysical false positives in a transit survey. From amongst these impostors, we have found two transiting planets. We discuss our follow-up observations of TrES-2, th...

O'Donovan, Francis T

2007-01-01

325

Using Stellar Densities to Evaluate Transiting Exoplanetary Candidates  

CERN Multimedia

One of the persistent complications in searches for transiting exoplanets is the low percentage of the detected candidates that ultimately prove to be planets, which significantly increases the load on the telescopes used for the follow-up observations to confirm or reject candidates. Several attempts have been made at creating techniques that can pare down candidate lists without the need of additional observations. Some of these techniques involve a detailed analysis of light curve characteristics; others estimate the stellar density or some proxy thereof. In this paper, we extend upon this second approach, exploring the use of independently-calculated stellar densities to identify the most promising transiting exoplanet candidates. We use a set of CoRoT candidates and the set of known transiting exoplanets to examine the potential of this approach. In particular, we note the possibilities inherent in the high-precision photometry from space missions, which can detect stellar asteroseismic pulsations from w...

Tingley, Brandon; Deeg, Hans-Jörg; 10.1088/0004-637X/726/2/112

2011-01-01

326

What asteroseismology can do for exoplanets: Kepler-410A b is a Small Neptune around a bright star, in an eccentric orbit consistent with low obliquity  

CERN Document Server

We confirm the Kepler planet candidate Kepler-410b (KOI-42b) as a Neptune sized exoplanet on a 17.8 day, eccentric orbit around the bright (Kp = 9.4) star Kepler-410A. This is the third brightest confirmed planet host star in the Kepler field and one of the brightest hosts of all currently known transiting exoplanets. Kepler-410 consists of a blend between the fast rotating planet host star (Kepler-410A) and a fainter star (Kepler-410B), which has complicated the confirmation of the planetary candidate. Employing asteroseismology, using constraints from the transit light curve, adaptive optics and speckle images, and Spitzer transit observations, we demonstrate that the candidate can only be an exoplanet orbiting Kepler-410A. Via asteroseismology we determine the following stellar and planetary parameters with high precision; M$_\\star = 1.214 \\pm 0.033$ M$_\\odot$, R$_\\star = 1.352 \\pm 0.010$ R$_\\odot$, Age = $2.76 \\pm 0.54$ Gyr, planetary radius ($2.838 \\pm 0.054$ R$_\\oplus$), and orbital eccentricity ($0.17^...

Van Eylen, Vincent; Aguirre, Victor Silva; Arentoft, Torben; Kjeldsen, Hans; Albrecht, Simon; Chaplin, William J; Isaacson, Howard; Pedersen, May G; Jessen-Hansen, Jens; Tingley, Brandon W; Christensen-Dalsgaard, Joergen; Aerts, Conny; Campante, Tiago L; Bryson, Stephen T

2013-01-01

327

Characterization of exoplanet atmospheres using high-dispersion spectroscopy with the E-ELT and beyond  

Science.gov (United States)

Ground-based high-dispersion (R ˜ 100,000) spectroscopy provides unique information on exoplanet atmospheres, inaccessible from space - even using the JWST or other future space telescopes. Recent successes in transmission- and dayside spectroscopy using CRIRES on the Very Large Telescope prelude the enormous discovery potential of high-dispersion spectrographs on the E-ELT, such as METIS in the thermal infrared, and HIRES in the optical/near-infrared. This includes the orbital inclination and masses of hundred(s) of non-transiting planets, line-by-line molecular band spectra, planet rotation and global wind patterns, longitudinal spectral variations, and possibly isotopologue ratios. Thinking beyond the E-ELT, we advocate that ultimately a systematic search for oxygen in atmospheres of nearby Earth-like planets can be conducted using large arrays of relatively low-cost flux collector telescopes equipped with high-dispersion spectrographs.

Snellen, Ignas

2013-04-01

328

JWST Exoplanet Characterization: Big Opportunities for Small Planets Around Small Stars  

Science.gov (United States)

The NASA Kepler Mission has revealed the startling fact that there exist at least 1.5 planets per M dwarf throughout the Galaxy. The vast majority of these planets have radii comparable to the Earth and orbital periods less than 20 days. As a result, the next generation of transit surveys, TESS in particular, will discover a large sample of small planets orbiting nearby red dwarfs. These host stars, while faint in optical bands will be bright in the NIR and the small radii of the stars will enable opportunities to study the internal structures and atmospheric compositions of terrestrial planets. I will provide an overview of the types of targets that will likely be available for study by the time of JWST's launch and take a look ahead at the exoplanet characterization science opportunities will be available with the JWST instrument suite.

Johnson, John A.

2014-01-01

329

Characterization of exoplanet atmospheres using high-dispersion spectroscopy with the E-ELT and beyond  

Directory of Open Access Journals (Sweden)

Full Text Available Ground-based high-dispersion (R ? 100,000 spectroscopy provides unique information on exoplanet atmospheres, inaccessible from space - even using the JWST or other future space telescopes. Recent successes in transmission- and dayside spectroscopy using CRIRES on the Very Large Telescope prelude the enormous discovery potential of high-dispersion spectrographs on the E-ELT, such as METIS in the thermal infrared, and HIRES in the optical/near-infrared. This includes the orbital inclination and masses of hundred(s of non-transiting planets, line-by-line molecular band spectra, planet rotation and global wind patterns, longitudinal spectral variations, and possibly isotopologue ratios. Thinking beyond the E-ELT, we advocate that ultimately a systematic search for oxygen in atmospheres of nearby Earth-like planets can be conducted using large arrays of relatively low-cost flux collector telescopes equipped with high-dispersion spectrographs.

Snellen Ignas

2013-04-01

330

Some inconvenient truths about biosignatures involving two chemical species on Earth-like exoplanets  

CERN Document Server

The detection of strong thermochemical disequilibrium in the atmosphere of an extrasolar planet is thought to be a potential biosignature. In this article we present a new kind of false positive that can mimic a disequilibrium or any other biosignature that involves two chemical species. We consider a scenario where the exoplanet hosts a moon that has its own atmosphere and neither of the atmospheres is in chemical disequilibrium. Our results show that the integrated spectrum of the planet and the moon closely resembles that of a single object in strong chemical disequilibrium. We derive a firm limit on the maximum spectral resolution that can be obtained for both directly-imaged and transiting planets. The spectral resolution of even idealized space-based spectrographs that might be achievable in the next several decades is in general insufficient to break the degeneracy. Both chemical species can only be definitively confirmed in the same object if absorption features of both chemicals can be unambiguously ...

Rein, Hanno; Spiegel, David S

2014-01-01

331

Stellar characterization of CoRoT/Exoplanet fields with MATISSE  

CERN Document Server

The homogeneous spectroscopic determination of the stellar parameters is a mandatory step for transit detections from space. Knowledge of which population the planet hosting stars belong to places constraints on the formation and evolution of exoplanetary systems. We used the FLAMES/GIRAFFE multi-fiber instrument at ESO to spectroscopically observe samples of stars in three CoRoT/Exoplanet fields, namely the LRa01, LRc01, and SRc01 fields, and characterize their stellar populations. We present accurate atmospheric parameters, Teff, logg, [M/H], and [$\\alpha$/Fe]\\ derived for 1227 stars in these fields using the \\matisse algorithm. The latter is based on the spectral synthesis methodology and automatically provides stellar parameters for large samples of observed spectra. We trained and applied this algorithm to \\flames observations covering the Mg \\textsc{i} b spectral range. It was calibrated on reference stars and tested on spectroscopic samples from other studies in the literature. The barycentric radial v...

Gazzano, J -C; Deleuil, M; Recio-Blanco, A; Bouchy, F; Moutou, C; Bijaoui, A; Ordenovic, C; Gandolfi, D; Loeillet, B; 10.1051/0004-6361/201014708

2010-01-01

332

ExoMol: molecular line lists for exoplanet and other atmospheres  

CERN Document Server

The discovery of extrasolar planets is one of the major scientific advances of the last two decades. Hundreds of planets have now been detected and astronomers are beginning to characterise their composition and physical characteristics. To do this requires a huge quantity of spectroscopic data most of which is not available from laboratory studies. The ExoMol project will offer a comprehensive solution to this problem by providing spectroscopic data on all the molecular transitions of importance in the atmospheres of exoplanets. These data will be widely applicable to other problems and will be used for studies on cool stars, brown dwarfs and circumstellar environments. This paper lays out the scientific foundations of this project and reviews previous work in this area. A mixture of first principles and empirically-tuned quantum mechanical methods will be used to compute comprehensive and very large rotation-vibration and rotation-vibration-electronic (rovibronic) line lists. Methodologies will be developed...

Tennyson, Jonathan

2012-01-01

333

Atmospheric dynamics of terrestrial exoplanets over a wide range of orbital and atmospheric parameters  

CERN Document Server

The recent discoveries of terrestrial exoplanets and super Earths extending over a broad range of orbital and physical parameters suggests that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone---including transitions to Snowball-like states and runaway-greenhouse feedbacks---depend on the equator-to-pole temperature differences, pattern of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model (GCM) including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. We show how the planetary rotation rate, planetary mass,...

Kaspi, Yohai

2014-01-01

334

The James Webb Space Telescope and its Potential for Exoplanet Science  

Science.gov (United States)

The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 microns to 28 microns. JWST s primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, and the formation of evolution of planetary systems. Recent progress in hardware development for the observatory will be presented, including a discussion of the status of JWST s optical system and Beryllium mirror fabrication, progress with sunshield prototypes, and recent changes in the integration and test configuration. We also review the expected scientific performance of the observatory for observations of exosolar planets by means of transit imaging and spectroscopy and direct imaging. We also review the recent discovery of Fomalhaut B and implications for debris disk imaging nd exoplanet detection with JWST.

Clampin, Mark

2008-01-01

335

Spin-Orbit Alignment for the Eccentric Exoplanet HD 147506b  

CERN Document Server

The short-period exoplanet HD 147506b (also known as HAT-P-2b) has an eccentric orbit, raising the possibility that it migrated through planet-planet scattering or Kozai oscillations accompanied by tidal dissipation. Either of these scenarios could have significantly tilted the orbit relative to the host star's equatorial plane. Here we present spectroscopy of a transit of HD 147506b, and assess the spin-orbit alignment via the Rossiter-McLaughlin effect. We find the sky projections of the stellar spin axis and orbital axis to be aligned within 14 deg. Thus we find no corroborating evidence for scattering or Kozai migration, although these scenarios cannot be ruled out with the present data.

Winn, Joshua N; Peek, Kathryn M G; Marcy, Geoffrey W; Bakos, Gaspar A; Enya, Keigo; Narita, Norio; Suto, Yasushi; Turner, Edwin L; Vogt, Steven S

2007-01-01

336

Carbon and Oxygen Abundances in the Hot Jupiter Exoplanet Host Star XO-2N and its Binary Companion  

CERN Multimedia

With the aim of connecting the compositions of stars and planets, we present the abundances of carbon and oxygen, as well as iron and nickel, for the transiting exoplanet host star XO-2N and its wide-separation binary companion XO-2S. Stellar parameters are derived from high-resolution, high-signal-to-noise spectra, and the two stars are found to be similar in their Teff, log g, iron ([Fe/H]), nickel ([Ni/H]) abundances. Their carbon ([C/H]) and oxygen ([O/H]) abundances also overlap within errors, although XO-2N may be slightly more C-rich and O-rich than XO-2S. The C/O ratios of both stars (~0.60+/-0.20) may also be somewhat larger than solar (C/O~0.50). The XO-2 system has a transiting hot Jupiter orbiting one binary component but not the other, allowing us to probe the potential effects planet formation might have on the host star composition. Additionally, with multiple observations of its atmosphere the transiting exoplanet XO-2b lends itself to compositional analysis, which can be compared to the natal...

Teske, Johanna K; Cunha, Katia; Smith, Verne V; Griffith, Caitlin A

2013-01-01

337

ELEVEN EXOPLANET HOST STAR ANGULAR DIAMETERS FROM THE CHARA ARRAY  

International Nuclear Information System (INIS)

We directly measured the angular diameters for 11 exoplanet host stars using Georgia State University's CHARA Array interferometer and calculated their linear radii and effective temperatures. The sample tends toward evolving or evolved stars and includes one dwarf, four subgiants, and six giants. We then estimated masses and ages for the stars using our effective temperatures combined with metallicity measurements from the literature.

2009-08-10

338

The CoRoT Exoplanet program: status & results  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The CoRoT satellite is the ?rst instrument hunting for planets from space. We will review the status of the CoRoT/Exoplanet program. We will then present the CoRoT exoplanetary systems and how they widen the range of properties of the close-in population and contribute to our understanding of the properties of planets.

Deleuil M.; Moutou C.; Bordé P.

2011-01-01

339

Transits of Earth-Like Planets  

CERN Multimedia

Transmission spectroscopy of Earth-like exoplanets is a potential tool for habitability screening. Transiting planets are present-day "Rosetta Stones" for understanding extrasolar planets because they offer the possibility to characterize giant planet atmospheres and should provide an access to biomarkers in the atmospheres of Earth-like exoplanets, once they are detected. Using the Earth itself as a proxy we show the potential and limits of the transiting technique to detect biomarkers on an Earth-analog exoplanet in transit. We quantify the Earths cross section as a function of wavelength, and show the effect of each atmospheric species, aerosol, and Rayleigh scattering. Clouds do not significantly affect this picture because the opacity of the lower atmosphere from aerosol and Rayleigh losses dominates over cloud losses. We calculate the optimum signal-to-noise ratio for spectral features in the primary eclipse spectrum of an Earth-like exoplanet around a Sun-like star and also M stars, for a 6.5-m telesco...

Kaltenegger, L

2009-01-01

340

The Lick-Carnegie Exoplanet Survey: A Saturn-Mass Planet in the Habitable Zone of the Nearby M4V Star HIP 57050  

CERN Document Server

Precision radial velocities from Keck/HIRES reveal a Saturn-mass planet orbiting the nearby M4V star HIP 57050. The planet has a minimum mass of 0.3 Jupiter-mass, an orbital period of 41.4 days, and an orbital eccentricity of 0.31. V-band photometry reveals a clear stellar rotation signature of the host star with a period of 98 days, well separated from the period of the radial velocity variations and reinforcing a Keplerian origin for the observed velocity variations. The orbital period of this planet corresponds to an orbit in the habitable zone of HIP 57050, with an expected planetary temperature of approximately 230 K. The star has a metallicity of [Fe/H] = 0.32+/-0.06 dex, of order twice solar and among the highest metallicity stars in the immediate solar neighborhood. This newly discovered planet provides further support that the well-known planet-metallicity correlation for F, G, and K stars also extends down into the M-dwarf regime. The a priori geometric probability for transits of this planet is onl...

Haghighipour, Nader; Butler, R Paul; Rivera, Eugenio J; Laughlin, Greg; Meschiari, Stefano; Henry, Gregory W

2010-01-01

 
 
 
 
341

CLIMATE INSTABILITY ON TIDALLY LOCKED EXOPLANETS  

International Nuclear Information System (INIS)

Feedbacks that can destabilize the climates of synchronously rotating rocky planets may arise on planets with strong day-night surface temperature contrasts. Earth-like habitable planets maintain stable surface liquid water over geologic time. This requires equilibrium between the temperature-dependent rate of greenhouse-gas consumption by weathering, and greenhouse-gas resupply by other processes. Detected small-radius exoplanets, and anticipated M-dwarf habitable-zone rocky planets, are expected to be in synchronous rotation (tidally locked). In this paper, we investigate two hypothetical feedbacks that can destabilize climate on planets in synchronous rotation. (1) If small changes in pressure alter the temperature distribution across a planet's surface such that the weathering rate goes up when the pressure goes down, a runaway positive feedback occurs involving increasing weathering rate near the substellar point, decreasing pressure, and increasing substellar surface temperature. We call this feedback enhanced substellar weathering instability (ESWI). (2) When decreases in pressure increase the fraction of surface area above the melting point (through reduced advective cooling of the substellar point), and the corresponding increase in volume of liquid causes net dissolution of the atmosphere, a further decrease in pressure will occur. This substellar dissolution feedback can also cause a runaway climate shift. We use an idealized energy balance model to map out the conditions under which these instabilities may occur. In this simplified model, the weathering runaway can shrink the habitable zone and cause geologically rapid 103-fold atmospheric pressure shifts within the habitable zone. Mars may have undergone a weathering runaway in the past. Substellar dissolution is usually a negative feedback or weak positive feedback on changes in atmospheric pressure. It can only cause runaway changes for small, deep oceans and highly soluble atmospheric gases. Both instabilities are suppressed if the atmosphere has a high radiative efficiency. Our results are most relevant for atmospheres that are thin, have low greenhouse-gas radiative efficiency, and have a principal greenhouse gas that is also the main constituent of the atmosphere. ESWI also requires land near the substellar point, and tectonic resurfacing (volcanism, mountain-building) is needed for large jumps in pressure. These results identify a new pathway by which habitable-zone planets can undergo rapid climate shifts and become uninhabitable.

2011-12-10

342

System Geometries and Transit/Eclipse Probabilities  

Directory of Open Access Journals (Sweden)

Full Text Available Transiting exoplanets provide access to data to study the mass-radius relation and internal structure of extrasolar planets. Long-period transiting planets allow insight into planetary environments similar to the Solar System where, in contrast to hot Jupiters, planets are not constantly exposed to the intense radiation of their parent stars. Observations of secondary eclipses additionally permit studies of exoplanet temperatures and large-scale exo-atmospheric properties. We show how transit and eclipse probabilities are related to planet-star system geometries, particularly for long-period, eccentric orbits. The resulting target selection and observational strategies represent the principal ingredients of our photometric survey of known radial-velocity planets with the aim of detecting transit signatures (TERMS.

Howard A.

2011-02-01

343

A search for transit timing variation  

Directory of Open Access Journals (Sweden)

Full Text Available Photometric follow-ups of transiting exoplanets (TEPs may lead to discoveries of additional, less massive bodies in extrasolar systems. This is possible by detecting and then analysing variations in transit timing of transiting exoplanets. In 2009 we launched an international observing campaign, the aim of which is to detect and characterise signals of transit timing variation (TTV in selected TEPs. The programme is realised by collecting data from 0.6-2.2-m telescopes spread worldwide at di?erent longitudes. We present our observing strategy and summarise ?rst results for WASP-3b with evidence for a 15 Earth-mass perturber in an outer 2:1 orbital resonance.

Kramm U.

2011-02-01

344

System Geometries and Transit / Eclipse Probabilities  

CERN Document Server

Transiting exoplanets provide access to data to study the mass-radius relation and internal structure of extrasolar planets. Long-period transiting planets allow insight into planetary environments similar to the Solar System where, in contrast to hot Jupiters, planets are not constantly exposed to the intense radiation of their parent stars. Observations of secondary eclipses additionally permit studies of exoplanet temperatures and large-scale exo-atmospheric properties. We show how transit and eclipse probabilities are related to planet-star system geometries, particularly for long-period, eccentric orbits. The resulting target selection and observational strategies represent the principal ingredients of our photometric survey of known radial-velocity planets with the aim of detecting transit signatures (TERMS).

von Braun, Kaspar; Mahadevan, Suvrath; Laughlin, Greg; Howard, Andrew; Ciardi, David R

2010-01-01

345

Direct Imaging of Planet Transit Events  

CERN Document Server

Exoplanet transit events are attractive targets for the ultrahigh-resolution capabilities afforded by optical interferometers. The intersection of two developments in astronomy enable direct imaging of exoplanet transits: first, improvements in sensitivity and precision of interferometric instrumentation; and second, identification of ever-brighter host stars. Efforts are underway for the first direct high-precision detection of closure phase signatures with the CHARA Array and Navy Precision Optical Interferometer. When successful, these measurements will enable recovery of the transit position angle on the sky, along with characterization of other system parameters, such as stellar radius, planet radius, and other parameters of the transit event. This technique can directly determine the planet's radius independent of any outside observations, and appears able to improve substantially upon other determinations of that radius; it will be possible to extract wavelength dependence of that radius determination,...

van Belle, Gerard T; Boyajian, Tabetha; Schaefer, Gail

2014-01-01

346

TASTE. II. A new observational study of transit time variations in HAT-P-13b  

CERN Multimedia

TASTE (The Asiago Search for Transit timing variations of Exoplanets) project is collecting high-precision, short-cadence light curves for a selected sample of transiting exoplanets. The hot jupiter HAT-P-13b has been claimed to have suddenly deviated from a linear ephemeris by ~20 min, suggesting the presence of a perturber in the system. Using five new transits, we discuss the plausibility of this transit time variation (TTV), and show that a periodic signal should not be excluded. More follow-up observations are required to constrain the mass and the orbit of the hypotetical perturber.

Nascimbeni, V; Bedin, L R; Damasso, M; Malavolta, L; Borsato, L

2011-01-01

347

Transmission spectroscopy of exoplanet XO-2b observed with HST NICMOS  

CERN Document Server

Spectroscopy during planetary transits is a powerful tool to probe exoplanet atmospheres. We present the near-infrared transit spectroscopy of XO-2b obtained with HST NICMOS. Uniquely for NICMOS transit spectroscopy, a companion star of similar properties to XO-2 is present in the field of view. We derive improved star and planet parameters through a photometric white-light analysis. We show a clear correlation of the spectrum noise with instrumental parameters, in particular the angle of the spectral trace on the detector. An MCMC method using a decorrelation from instrumental parameters is used to extract the planetary spectrum. Spectra derived independently from each of the 3 visits have a RMS of 430, 510, and 1000 ppm respectively. The same analysis is performed on the companion star after numerical injection of a transit with a depth constant at all wavelengths. The extracted spectra exhibit residuals of similar amplitude as for XO-2, which represent the level of remaining NICMOS systematics. This shows ...

Crouzet, Nicolas; Burke, Christopher J; Long, Douglas

2012-01-01

348

Transit timing analysis in the HAT-P-32 system  

Science.gov (United States)

We present the results of 45 transit observations obtained for the transiting exoplanet HAT-P-32b. The transits have been observed using several telescopes mainly throughout the YETI (Young Exoplanet Transit Initiative) network. In 25 cases, complete transit light curves with a timing precision better than 1.4 min have been obtained. These light curves have been used to refine the system properties, namely inclination i, planet-to-star radius ratio Rp/Rs, and the ratio between the semimajor axis and the stellar radius a/Rs. First analyses by Hartman et al. suggests the existence of a second planet in the system, thus we tried to find an additional body using the transit timing variation (TTV) technique. Taking also the literature data points into account, we can explain all mid-transit times by refining the linear ephemeris by 21 ms. Thus, we can exclude TTV amplitudes of more than ˜1.5 min.

Seeliger, M.; Dimitrov, D.; Kjurkchieva, D.; Mallonn, M.; Fernandez, M.; Kitze, M.; Casanova, V.; Maciejewski, G.; Ohlert, J. M.; Schmidt, J. G.; Pannicke, A.; Puchalski, D.; Gö?ü?, E.; Güver, T.; Bilir, S.; Ak, T.; Hohle, M. M.; Schmidt, T. O. B.; Errmann, R.; Jensen, E.; Cohen, D.; Marschall, L.; Saral, G.; Bernt, I.; Derman, E.; Ga?an, C.; Neuhäuser, R.

2014-06-01

349

Transits of WASP-33 (Herrero+, 2011)  

Science.gov (United States)

This tables list the R-band photometric follow-up of WASP-33 from the Montsec Observatory used in this paper and also the out-of-transit follow-up photometry taken from Montcabrer Observatory. All the other data used in the paper (from other authors) is available at the Exoplanet Transit Database (ETD, http://var2.astro.cz/ETD). (4 data files).

Herrero, E.; Morales, J. C.; Ribas, I.; Naves, R.

2011-01-01

350

Selection of Nearby Star Targets for the Subaru Strategic Exploration of Exoplanets and Disks  

Science.gov (United States)

SEEDS (the Subaru Strategic Exploration of Exoplanets and Disks with Hi-CIAO/AO188) is a strategic five-year campaign of direct imaging surveys of exoplanets/disks using the Subaru telescope equipped with the new adaptive optics system AO188 and our new high-contrast instrument, HiCIAO. The goals of the survey are to address the following key issues in exoplanet/disk sciences: (1) the detection and census of exoplanets; (2) the evolution of protoplanetary and debris disks; and (3) the link between exoplanets and disks. Targets prepared for the SEEDS exoplanet searches are in four categories, including nearby stars. We present our scientific motivations and current status of the SEEDS target selection in the nearby stars category.

Kandori, R.; Tamura, M.; Morino, J.; Ishii, M.; Suzuki, R.; Hashimoto, J.; Kusakabe, N.; Narita, N.; Sato, B.; Yamada, T.; Enya, K.; Goto, M.; Carson, J.; Thalmann, C.; McElwain, M.; Moro-Martin, A.; Knapp, J.; Turner, E. L.

2009-08-01

351

Correlations between the stellar, planetary, and debris components of exoplanet systems observed by Herschel  

Science.gov (United States)

Context. Stars form surrounded by gas- and dust-rich protoplanetary discs. Generally, these discs dissipate over a few (3-10) Myr, leaving a faint tenuous debris disc composed of second-generation dust produced by the attrition of larger bodies formed in the protoplanetary disc. Giant planets detected in radial velocity and transit surveys of main-sequence stars also form within the protoplanetary disc, whilst super-Earths now detectable may form once the gas has dissipated. Our own solar system, with its eight planets and two debris belts, is a prime example of an end state of this process. Aims: The Herschel DEBRIS, DUNES, and GT programmes observed 37 exoplanet host stars within 25 pc at 70, 100, and 160 ?m with the sensitivity to detect far-infrared excess emission at flux density levels only an order of magnitude greater than that of the solar system's Edgeworth-Kuiper belt. Here we present an analysis of that sample, using it to more accurately determine the (possible) level of dust emission from these exoplanet host stars and thereafter determine the links between the various components of these exoplanetary systems through statistical analysis. Methods: We have fitted the flux densities measured from recent Herschel observations with a simple two parameter (Td, LIR/L?) black-body model (or to the 3? upper limits at 100 ?m). From this uniform approach we calculated the fractional luminosity, radial extent and dust temperature. We then plotted the calculated dust luminosity or upper limits against the stellar properties, e.g. effective temperature, metallicity, and age, and identified correlations between these parameters. Results: A total of eleven debris discs are identified around the 37 stars in the sample. An incidence of ten cool debris discs around the Sun-like exoplanet host stars (29 ± 9%) is consistent with the detection rate found by DUNES (20.2 ± 2.0%). For the debris disc systems, the dust temperatures range from 20 to 80 K, and fractional luminosities (LIR/L?) between 2.4 ×10-6 and 4.1 ×10-4. In the case of non-detections, we calculated typical 3? upper limits to the dust fractional luminosities of a few ×10-6. Conclusions: We recover the previously identified correlation between stellar metallicity and hot-Jupiter planets in our data set. We find a correlation between the increased presence of dust, lower planet masses, and lower stellar metallicities. This confirms the recently identified correlation between cold debris discs and low-mass planets in the context of planet formation by core accretion. Tables 2-4 are available in electronic form at http://www.aanda.org

Marshall, J. P.; Moro-Martín, A.; Eiroa, C.; Kennedy, G.; Mora, A.; Sibthorpe, B.; Lestrade, J.-F.; Maldonado, J.; Sanz-Forcada, J.; Wyatt, M. C.; Matthews, B.; Horner, J.; Montesinos, B.; Bryden, G.; del Burgo, C.; Greaves, J. S.; Ivison, R. J.; Meeus, G.; Olofsson, G.; Pilbratt, G. L.; White, G. J.

2014-05-01

352

Transit Detection in the MEarth Survey of Nearby M Dwarfs: Bridging the Clean-First, Search-Later Divide  

CERN Document Server

In the effort to characterize the masses, radii, and atmospheres of potentially habitable exoplanets, there is an urgent need to find examples of such planets transiting nearby M dwarfs. The MEarth Project is an ongoing effort to do so, as a ground-based photometric survey designed to detect exoplanets as small as 2 Earth radii transiting mid-to-late M dwarfs within 33 pc of the Sun. Unfortunately, identifying transits of such planets in photometric monitoring is complicated both by the intrinsic stellar variability that is common among these stars and by the nocturnal cadence, atmospheric variations, and instrumental systematics that often plague Earth-bound observatories. Here we summarize the challenges MEarth faces, and address them with a new framework to detect shallow exoplanet transits in wiggly and irregularly-spaced light curves. In contrast to previous methods that clean trends from light curves before searching for transits, this framework assesses the significance of individual transits simultane...

Berta, Zachory K; Charbonneau, David; Burke, Christopher J; Falco, Emilio E

2012-01-01

353

Models of Stars, Brown Dwarfs and Exoplanets  

CERN Multimedia

Within the next few years, GAIA and several instruments aiming at imag- ing extrasolar planets will see first light. In parallel, low mass planets are being searched around red dwarfs which offer more favourable conditions, both for radial velocity de- tection and transit studies, than solar-type stars. Authors of the model atmosphere code which has allowed the detection of water vapour in the atmosphere of Hot Jupiters re- view recent advancement in modelling the stellar to substellar transition. The revised solar oxygen abundances and cloud model allow for the first time to reproduce the pho- tometric and spectroscopic properties of this transition. Also presented are highlight results of a model atmosphere grid for stars, brown dwarfs and extrasolar planets.

Allard, France; Freytag, Bernd

2011-01-01

354

Hubble Space Telescope High Resolution Imaging of Kepler Small and Cool Exoplanet Host Stars  

CERN Document Server

High resolution imaging is an important tool for follow-up study of exoplanet candidates found via transit detection with the Kepler Mission. We discuss here HST imaging with the WFC3 of 23 stars that host particularly interesting Kepler planet candidates based on their small size and cool equilibrium temperature estimates. Results include detections, exclusion of background stars that could be a source of false positives for the transits, and detection of physically-associated companions in a number of cases providing dilution measures necessary for planet parameter refinement. For six KOIs, we find that there is ambiguity in which star hosts the transiting planet(s), with potentially strong implications for planetary characteristics. Our sample is evenly distributed in G, K, and M spectral types. Albeit with a small sample size, we find that physically-associated binaries are more common than expected at each spectral type, reaching a factor of 10 frequency excess at M. We document the program detection sen...

Gilliland, Ronald L; Adams, Elisabeth R; Ciardi, David R; Kalas, Paul; Wright, Jason T

2014-01-01

355

APIC. Absolute Position Interfero-Coronagraph for direct exoplanet detection  

Science.gov (United States)

Context: For detecting and directly imaging exoplanets, coronagraphic methods are mandatory when the intensity ratio between a star and its orbiting planet can be as large as 10^6. In 1996, a concept of an achromatic interfero-coronagraph (AIC) was presented for detecting very faint stellar companions, such as exoplanets. Aims: We present a modified version of the AIC not only permitting these faint companions to be detected but also their relative position to be determined with respect to the parent star, a problem that was not solved in the original design of the AIC. Methods: In our modified design, two cylindrical lens doublets were used to remove the 180° ambiguity introduced by the AIC's original design. Results: Our theoretical study and the numerical computations show that the axis of symmetry is destroyed when one of the cylindrical doublets is rotated around the optical axis.

Allouche, F.; Glindemann, A.; Aristidi, E.; Vakili, F.

2009-06-01

356

SPEED: the Segmented Pupil Experiment for Exoplanet Detection  

CERN Document Server

Searching for nearby exoplanets with direct imaging is one of the major scientific drivers for both space and ground-based programs. While the second generation of dedicated high-contrast instruments on 8-m class telescopes is about to greatly expand the sample of directly imaged planets, exploring the planetary parameter space to hitherto-unseen regions ideally down to Terrestrial planets is a major technological challenge for the forthcoming decades. This requires increasing spatial resolution and significantly improving high contrast imaging capabilities at close angular separations. Segmented telescopes offer a practical path toward dramatically enlarging telescope diameter from the ground (ELTs), or achieving optimal diameter in space. However, translating current technological advances in the domain of high-contrast imaging for monolithic apertures to the case of segmented apertures is far from trivial. SPEED (the segmented pupil experiment for exoplanet detection) is a new instrumental facility in deve...

Patrice, Martinez; Carole, Gouvret; Julien, Dejongue; Jean-Baptiste, Daban; Alain, Spang; Frantz, Martinache; Mathilde, Beaulieu; Pierre, Janin-Potiron; Lyu, Abe; Yan, Fantei-Caujolle; Damien, Mattei; Sebastien, Ottogali

2014-01-01

357

THE FATE OF MOONS OF CLOSE-IN GIANT EXOPLANETS  

International Nuclear Information System (INIS)

We show that the fate of moons of a close-in giant planet is mainly determined by the migration history of the planet in the protoplanetary disk. As the planet migrates in the disk from beyond the snow line toward a multi-day period orbit, the formed and forming moons become unstable as the planet's sphere of influence shrinks. Disk-driven migration is faster than the moons' tidal orbital evolution. Moons are eventually ejected from around close-in exoplanets or forced into collision with them before tides from the planet affect their orbits. If moons are detected around close-in exoplanets, they are unlikely to have been formed in situ, instead they were captured from the protoplanetary disk on retrograde orbits around the planets.

2010-08-20

358

Ranges of Atmospheric Mass and Composition of Super Earth Exoplanets  

CERN Multimedia

Terrestrial-like exoplanets may obtain atmospheres from three primary sources: Capture of nebular gases, degassing during accretion, and degassing from subsequent tectonic activity. Here we model degassing during accretion to estimate the range of atmospheric mass and composition on exoplanets ranging from 1 to 30 Earth masses. We use bulk compositions drawn from primitive and differentiated meteorite compositions. Degassing alone can create a wide range of masses of planetary atmospheres, ranging from less than a percent of the planet's total mass up to ~6 mass% of hydrogen, ~20 mass% of water, and/or ~5 mass% of carbon compounds. Hydrogen-rich atmospheres can be outgassed as a result of oxidizing metallic iron with water, and excess water and carbon can produce atmospheres through simple degassing. As a byproduct of our atmospheric outgassing models we find that modest initial water contents (10 mass% of the planet and above) create planets with deep surface liquid water oceans soon after accretion is compl...

Elkins-Tanton, L

2008-01-01

359

Achieving high-precision pointing on ExoplanetSat: initial feasibility analysis  

Science.gov (United States)

ExoplanetSat is a proposed three-unit CubeSat designed to detect down to Earth-sized exoplanets in an orbit out to the habitable zone of Sun-like stars via the transit method. To achieve the required photometric precision to make these measurements, the target star must remain within the same fraction of a pixel, which is equivalent to controlling the pointing of the satellite to the arcsecond level. The satellite will use a two-stage control system: coarse control will be performed by a set of reaction wheels, desaturated by magnetic torque coils, and fine control will be performed by a piezoelectric translation stage. Since no satellite of this size has previously demonstrated this high level of pointing precision, a simulation has been developed to prove the feasibility of realizing such a system. The current baseline simulation has demonstrated the ability to hold the target star to within 0.05 pixels or 1.8 arcseconds (with an 85 mm lens and 15 ?m pixels), in the presence of large reaction wheel disturbances as well as external environmental disturbances. This meets the current requirement of holding the target star to 0.14 pixels or 5.0 arcseconds. Other high-risk aspects of the design have been analyzed such as the effect of changing the guide star centroiding error, changing the CMOS sampling frequency, and reaction wheel selection on the slew performance of the satellite. While these results are promising as an initial feasibility analysis, further model improvements and hardware-in-the-loop tests are currently underway.

Pong, Christopher M.; Lim, Sungyung; Smith, Matthew W.; Miller, David W.; Villaseñor, Jesus S.; Seager, Sara

2010-07-01

360

Diversity among other worlds: characterization of exoplanets by direct detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The physical characterization of exoplanets will require to take spectra at several orbital positions. For that purpose, a direct imaging capability is necessary. Direct imaging requires an efficient stellar suppression mechanism, associated with an ultrasmooth telescope. We show that before future large space missions (interferometer, 4-8 m class coronograph, external occulter or Fresnel imager), direct imaging of giant planets and close-by super-Earth are at the cross-road...

Schneider, J.; Boccaletti, A.; Aylward, A.; Baudoz, P.; Beuzit, J. -l; Brown, R.; Cho, J.; Dohlen, K.; Ferrari, M.; Galicher, R.; Grasset, O.; Grenfell, L.; Griessmeier, J. -m; Guyon, O.; Hough, J.

2008-01-01

 
 
 
 
361

The CoRoT Exoplanet program: status & results  

Directory of Open Access Journals (Sweden)

Full Text Available The CoRoT satellite is the ?rst instrument hunting for planets from space. We will review the status of the CoRoT/Exoplanet program. We will then present the CoRoT exoplanetary systems and how they widen the range of properties of the close-in population and contribute to our understanding of the properties of planets.

Moutou C.

2011-02-01

362

The Status of Spectroscopic Data for the Exoplanet Characterisation Missions  

CERN Document Server

The status of laboratory spectroscopic data for exoplanet characterisation missions such as EChO is reviewed. For many molecules (eg H2O, CO, CO2, H3+, O2, O3) the data are already available. For the other species work is actively in progress constructing this data. Much of the is work is being undertaken by ExoMol project (www.exomol.com). This information will be used to construct and EChO-specific spectroscopic database.

Tennyson, Jonathan

2014-01-01

363

A rheophysical tidal theory for exoplanets and satellites  

Science.gov (United States)

Presentation of a new rheophysical theory of the bodily tides of exoplanets and planetary satellites. The basic mechanism is a Newtonian creep of the bodies when submitted to a tidal potential. The theory is applied to determine the pseudosynchronous rotation of companions and the energy dissipation due to bodily tides. The results are different if the body is "hard", as terrestrial planets, super-Earths and satellites, or "soft" as giant planets, hot Jupiters or stars.

Ferraz-Mello, S.

2012-09-01

364

The status of spectroscopic data for the exoplanet characterisation missions  

Science.gov (United States)

The status of laboratory spectroscopic data for exoplanet characterisation missions such as EChO is reviewed. For many molecules (eg H 2O, CO, CO 2, H 3+, O 2, O 3) the data are already available. For the other species work is actively in progress constructing this data. Much of the is work is being undertaken by ExoMol project (www.exomol.com). This information can be used to construct a mission-specific spectroscopic database.

Tennyson, Jonathan; Yurchenko, Sergei N.

2014-05-01

365

Galactic cosmic ray-induced radiation dose on terrestrial exoplanets.  

Science.gov (United States)

This past decade has seen tremendous advancements in the study of extrasolar planets. Observations are now made with increasing sophistication from both ground- and space-based instruments, and exoplanets are characterized with increasing precision. There is a class of particularly interesting exoplanets that reside in the habitable zone, which is defined as the area around a star where the planet is capable of supporting liquid water on its surface. Planetary systems around M dwarfs are considered to be prime candidates to search for life beyond the Solar System. Such planets are likely to be tidally locked and have close-in habitable zones. Theoretical calculations also suggest that close-in exoplanets are more likely to have weaker planetary magnetic fields, especially in the case of super-Earths. Such exoplanets are subjected to a high flux of galactic cosmic rays (GCRs) due to their weak magnetic moments. GCRs are energetic particles of astrophysical origin that strike the planetary atmosphere and produce secondary particles, including muons, which are highly penetrating. Some of these particles reach the planetary surface and contribute to the radiation dose. Along with the magnetic field, another factor governing the radiation dose is the depth of the planetary atmosphere. The higher the depth of the planetary atmosphere, the lower the flux of secondary particles will be on the surface. If the secondary particles are energetic enough, and their flux is sufficiently high, the radiation from muons can also impact the subsurface regions, such as in the case of Mars. If the radiation dose is too high, the chances of sustaining a long-term biosphere on the planet are very low. We have examined the dependence of the GCR-induced radiation dose on the strength of the planetary magnetic field and its atmospheric depth, and found that the latter is the decisive factor for the protection of a planetary biosphere. PMID:24143867

Atri, Dimitra; Hariharan, B; Grießmeier, Jean-Mathias

2013-10-01

366

Chemical Timescales in the Atmospheres of Highly Eccentric Exoplanets  

CERN Document Server

Close-in exoplanets with highly eccentric orbits are subject to large variations in incoming stellar flux between periapse and apoapse. These variations may lead to large swings in atmospheric temperature, which in turn may cause changes in the chemistry of the atmosphere from higher CO abundances at periapse to higher CH4 abundances at apoapse. Here we examine chemical timescales for CO\\rightleftarrowsCH4 interconversion compared to orbital timescales and vertical mixing timescales for the highly eccentric exoplanets HAT-P-2b and CoRoT-10b. As exoplanet atmospheres cool, the chemical timescales for CO\\rightleftarrowsCH4 tend to exceed orbital and/or vertical mixing timescales, leading to quenching. The relative roles of orbit-induced thermal quenching and vertical quenching depends upon mixing timescales relative to orbital timescales. For both HAT-P-2b and CoRoT-10b, vertical quenching will determine disequilibrium CO\\rightleftarrowsCH4 chemistry at faster vertical mixing rates (Kzz > 10^7 cm^2 s^-1), where...

Visscher, Channon

2012-01-01

367

Theoretical Albedo Spectra of Exoplanet Direct Imaging Targets  

Science.gov (United States)

Space-based coronagraphic telescopes currently under study would enable direct imaging of scattered light from giant exoplanets in orbits beyond 1 AU from their host stars. Considering the known radial-velocity planets alone, directly imaged planets will encompass a broad range of atmospheric properties, including a number of possible cloud species. Here we present theoretical albedo spectra (0.35 to 1 micron) for the most favorable targets for spaced-based coronagraph observations (good angular resolution and contrast) from the current population of known radial-velocity planets. We consider a range of internal temperatures and atmospheric metallicities as constrained by the system ages and planetary minimum masses. Additionally, we construct a grid of theoretical Jupiter and Neptune-like exoplanets around a variety of host stars at distances of 1, 3, and 5 AU. From this grid, we identify spectral and photometric signatures associated with planetary gravity, cloudiness, and composition that can used to select promising new targets as they are discovered. This work will help to guide the development and initial interpretation of a range of direct imaging exoplanet studies that will shed new light on important physical processes underlying giant planet formation and evolution.

Lewis, Nikole; Marley, Mark S.; Fortney, Jonathan J.

2014-06-01

368

A new interferometric study of four exoplanet host stars : {\\theta} Cygni, 14 Andromedae, {\\upsilon} Andromedae and 42 Draconis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Studying exoplanet host stars is of the utmost importance to establish the link between the presence of exoplanets around various types of stars and to understand the respective evolution of stars and exoplanets. Using the limb-darkened diameter (LDD) obtained from interferometric data, we determine the fundamental parameters of four exoplanet host stars. We are particularly interested in the F4 main-sequence star, {\\theta} Cyg, for which Kepler has recently revealed solar...

Ligi, R.; Mourard, D.; Lagrange, A. M.; Perraut, K.; Boyajian, T.; Be?rio, Ph; Nardetto, N.; Tallon-bosc, I.; Mcalister, H.; Brummelaar, T. Ten; Ridgway, S.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.

2012-01-01

369

Transit and Radial Velocity Survey Efficiency Comparison for a Habitable Zone Earth  

CERN Document Server

Transit and radial velocity searches are two techniques for identifying nearby extrasolar planets to Earth that transit bright stars. Identifying a robust sample of these exoplanets around bright stars for detailed atmospheric characterization is a major observational undertaking. In this study we describe a framework that answers the question of whether a transit or radial velocity survey is more efficient at finding transiting exoplanets given the same amount of observing time. Within the framework we show that a transit survey's window function can be approximated using the hypergeometric probability distribution. We estimate the observing time required for a transit survey to find a transiting Earth-sized exoplanet in the HZ with an emphasis on late type stars. We also estimate the radial velocity precision necessary to detect the equivalent HZ Earth-mass exoplanet that also transits when using an equal amount of observing time as the transit survey. We find that a radial velocity survey with sig_rv~0.6 m...

Burke, Christopher J

2014-01-01

370

Kepler Stars with Multiple Transiting Planet Candidates  

Science.gov (United States)

NASA's Kepler spacecraft was launched into an Earth-trailing heliocentric orbit in March of 2009. Kepler is designed to conduct a statistical census of planetary system properties using transit photometry. Among the most exciting early results from Kepler are target stars found to have photometric signatures that suggest the presence of more than one transiting planet. Individual transiting planets provide information on the size and orbital period distributions of exoplanets. Multiple transiting planets provide additional information on the spacing and flatness distributions of planetary systems. Results to d ate and plans for future analysis will be presented.

Lissauer, Jack J.

2012-01-01

371

Observing the Earth as an exoplanet with LOUPE, the Lunar Observatory for Unresolved Polarimetry of Earth  

CERN Document Server

The detections of small, rocky exoplanets have surged in recent years and will likely continue to do so. To know whether a rocky exoplanet is habitable, we have to characterise its atmosphere and surface. A promising characterisation method for rocky exoplanets is direct detection using spectropolarimetry. This method will be based on single pixel signals, because spatially resolving exoplanets is impossible with current and near-future instruments. Well-tested retrieval algorithms are essential to interpret these single pixel signals in terms of atmospheric composition, cloud and surface coverage. Observations of Earth itself provide the obvious benchmark data for testing such algorithms. The observations should provide signals that are integrated over the Earth's disk, that capture day and night variations, and all phase angles. The Moon is a unique platform from where the Earth can be observed as an exoplanet, undisturbed, all of the time. Here, we present LOUPE, the Lunar Observatory for Unresolved Polari...

Karalidi, T; Snik, F; Bagnulo, S; Sparks, W B; Keller, C U

2012-01-01

372

Asteroseismic Determination of Obliquities of the Exoplanet Systems Kepler-50 and Kepler-65  

DEFF Research Database (Denmark)

Results on the obliquity of exoplanet host starsâ??the angle between the stellar spin axis and the planetary orbital axisâ??provide important diagnostic information for theories describing planetary formation. Here we present the first application of asteroseismology to the problem of stellar obliquity determination in systems with transiting planets and Sun-like host stars. We consider two systems observed by the NASA Kepler mission which have multiple transiting small (super-Earth sized) planets: the previously reported Kepler-50 and a new system, Kepler-65, whose planets we validate in this paper. Both stars show rich spectra of solar-like oscillations. From the asteroseismic analysis we find that each host has its rotation axis nearly perpendicular to the line of sight with the sines of the angles constrained at the 1Ï? level to lie above 0.97 and 0.91, respectively. We use statistical arguments to show that coplanar orbits are favored in both systems, and that the orientations of the planetary orbits and the stellar rotation axis are correlated.

Chaplin, W. J.; Sanchis-Ojeda, R.

2013-01-01

373

Asteroseismic determination of obliquities of the exoplanet systems kepler-50 and kepler-65  

DEFF Research Database (Denmark)

Results on the obliquity of exoplanet host stars - the angle between the stellar spin axis and the planetary orbital axis - provide important diagnostic information for theories describing planetary formation. Here we present the first application of asteroseismology to the problem of stellar obliquity determination in systems with transiting planets and Sun-like host stars. We consider two systems observed by the NASA Kepler mission which have multiple transiting small (super-Earth sized) planets: the previously reported Kepler-50 and a new system, Kepler-65, whose planets we validate in this paper. Both stars show rich spectra of solar-like oscillations. From the asteroseismic analysis we find that each host has its rotation axis nearly perpendicular to the line of sight with the sines of the angles constrained at the 1s level to lie above 0.97 and 0.91, respectively. We use statistical arguments to show that coplanar orbits are favored in both systems, and that the orientations of the planetary orbits and the stellar rotation axis are correlated. © 2013. The American Astronomical Society. All rights reserved..

Chaplin, W.J.; Campante, T.L.

2013-01-01

374

Hubble Space Telescope detection of oxygen in the atmosphere of exoplanet HD189733b  

CERN Document Server

Detecting heavy atoms in the inflated atmospheres of giant exoplanets that orbit close to their parent stars is a key factor for understanding their bulk composition, and the processes that drive their expansion and interaction with the impinging stellar wind. Here, we use archive data obtained with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope to report an absorption of ~6.4+/-1.8% by neutral oxygen during the HD 189733b transit. Scaling published HI results from a simple hydrodynamic model of HD 189733b, a vertical OI column density of ~8x10^15/cm2 produces only a 3.5% attenuation, implying that non-thermal line broadening or super-solar abundances are required. We also report evidence of short-time variability in the measured stellar flux, a variability that we analyze and compare to solar flaring activity. In that frame, we find that non-statistical uncertainties in the measured fluxes are not negligible, which calls for caution when reporting transit absorptions. Despite these uncert...

Ben-Jaffel, Lotfi

2013-01-01

375

The multiplicity of exoplanet host stars - New low-mass stellar companions of the exoplanet host stars HD125612 and HD212301  

CERN Multimedia

Aims: We present new results from our ongoing multiplicity study of exoplanet host stars, carried out with SofI/NTT. We provide the most recent list of confirmed binary and triple star systems that harbor exoplanets. Methods: We use direct imaging to identify wide stellar and substellar companions as co-moving objects to the observed exoplanet host stars, whose masses and spectral types are determined with follow-up photometry and spectroscopy. Results: We found two new co-moving companions of the exoplanet host stars HD125612 and HD212301. HD125612B is a wide M4 dwarf (0.18 Msun) companion of the exoplanet host star HD125612, located about 1.5 arcmin (~4750 AU of projected separation) south-east of its primary. In contrast, HD212301B is a close M3 dwarf (0.35 Msun), which is found about 4.4 arcsec (~230 AU of projected separation) north-west of its primary. Conclusions: The binaries HD125612AB and HD212301AB are new members in the continuously growing list of exoplanet host star systems of which 43 are prese...

Mugrauer, M

2008-01-01

376

New results from the multi-object Keck Exoplanet Tracker  

Directory of Open Access Journals (Sweden)

Full Text Available The W. M. Keck Exoplanet Tracker is a pre- cision Doppler radial velocity instrument for extrasolar planet detection based on a new technique, dispersed fixed-delay interferome- try (DFDI, which allows for multi-object sur- veying for the first time. Installed at the 2.5- m Sloan telescope at Apache Point Observa- tory, the combination of Michelson interfer- ometer and medium resolution spectrograph (Erskine & Ge 2000; Ge 2002 allows design for simultaneous Doppler measurements of 60 targets (Ge et al. 2005.

J. C. van Eyken

2007-01-01

377

Exoplanet Science from NASA’s Kepler Mission  

Energy Technology Data Exchange (ETDEWEB)

NASA's exoplanet mission is the world's premier instrument for the discovery and study of planets orbiting distant stars. As the nominal mission comes to a close, Kepler has discovered nearly 2500 planet candidates, confirmed dozens of multi-planet systems, provided important insights into the orbital architectures of planetary systems, identified specific systems that challenge theories of planet formation and dynamical evolution, has revolutionized our understanding of stellar interiors, and is gearing to measure the frequency of Earth-like planets in the habitable zones of Sun-like stars in its extended mission phase. I present the most recent results from the Kepler mission.

Steffen, Jason [Northwestern University

2012-09-12

378

Direct detection and spectral characterization of outer exoplanets with the SPICA coronagraph instrument (SCI)  

CERN Document Server

The SPICA coronagraph instrument (SCI) provides high-contrast imaging and moderate resolution (R < 200) spectroscopy at the wavelength range from 3.5 to 27 \\mu m. Based on the planet evolutional model calculated by Burrows et al. (2003), SCI will search for gas giant planets down to one Jupiter mass around nearby young (1 Gyr) stars and two Jupiter masses around nearby old (5 Gyr) stars. SCI also allows to characterizing those planets of less than 1 Gyr by spectroscopic observations to reveal the nature of planetary formation and evolution. Focusing on the high sensitivity and high contrast at wavelengths longer than 10 \\mu m, we show that SCI also allows us to directly image icy giant planets like Uranus and Neptune as well as gas giant planets around nearby early-type stars. In this paper, we compare the capabilities of SCI and the JWST coronagraphs and also discuss a new approach to answering questions concerning the formation and evolution of planetary systems through planet detection with SCI.

Matsuo, Taro; Kotani, Takayuki; Itoh, Yoichi; Tamura, Motohide; Nakagawa, Takao; Enya, Keigo

2011-01-01

379

Water Clouds in Y Dwarfs and Exoplanets  

CERN Document Server

The formation of clouds affects brown dwarf and planetary atmospheres of nearly all effective temperatures. Iron and silicate condense in L dwarf atmospheres and dissipate at the L/T transition. Minor species such as sulfides and salts condense in mid-late T dwarfs. For brown dwarfs below Teff=450 K, water condenses in the upper atmosphere to form ice clouds. Currently over a dozen objects in this temperature range have been discovered, and few previous theoretical studies have addressed the effect of water clouds on brown dwarf or exoplanetary spectra. Here we present a new grid of models that include the effect of water cloud opacity. We find that they become optically thick in objects below Teff=350-375 K. Unlike refractory cloud materials, water ice particles are significantly non-gray absorbers; they predominantly scatter at optical wavelengths through J band and absorb in the infrared with prominent features, the strongest of which is at 2.8 microns. H2O, NH3, CH4, and H2 CIA are dominant opacity source...

Morley, Caroline V; Fortney, Jonathan J; Lupu, Roxana; Saumon, Didier; Greene, Tom; Lodders, Katharina

2014-01-01

380

Optical Phase Curves of Kepler Exoplanets  

CERN Document Server

We have conducted a comprehensive search for optical phase variations of all planet candidates with tight orbits in fifteen quarters of data from the Kepler space telescope. After correcting for systematics, we found eight systems that appear to show secondary eclipses as well as phase variations. Of these, five (Kepler-5, Kepler-6, Kepler-8, KOI-64 and KOI-2133) are new and three (TrES-2, HAT-P-7 and KOI-13) have previously published phase curves, albeit with many fewer observations. We model the full phase curve of each planet candidate, including the primary and secondary transits, and derive their albedos, day- and night-side temperatures, ellipsoidal variations and Doppler beaming. We find that KOI-64 and KOI-2133 have night-side temperatures well above their equilibrium values (while KOI-2133 also has an albedo >1), so we conclude that they are likely to be self-luminous objects rather than planets. The characteristics of the six other candidates are consistent with their being planets with low geometri...

Esteves, Lisa J; Jayawardhana, Ray

2013-01-01

 
 
 
 
381

The TERMS Project: Systematic Transit Exclusion  

Science.gov (United States)

Transiting planet discoveries have yielded a plethora of information regarding the internal structure and atmospheres of extra-solar planets. These discoveries have been restricted to the low-periastron distance regime due to the bias inherent in the geometric transit probability. Monitoring known radial velocity planets at predicted transit times is a proven method of detecting transits, and presents an avenue through which to explore the mass-radius relationship of exoplanets at long periods around bright host stars. Here we describe transit window calculations for known radial velocity planets, techniques for refining their transit ephemerides, and observational methods for obtaining maximum coverage of transit windows. These methods are currently being implemented by the Transit Ephemeris Refinement and Monitoring Survey (TERMS), from which we present the latest results.

Kane, Stephen R.; Ciardi, D.; Dragomir, D.; Fischer, D.; Henry, G.; Howard, A.; Jensen, E.; Laughlin, G.; Mahadevan, S.; Pilyavsky, G.; von Braun, K.; Wang, X.; Wright, J.

2011-09-01

382

Water Clouds in Y Dwarfs and Exoplanets  

Science.gov (United States)

The formation of clouds affects brown dwarf and planetary atmospheres of nearly all effective temperatures. Iron and silicate condense in L dwarf atmospheres and dissipate at the L/T transition. Minor species such as sulfides and salts condense in mid- to late T dwarfs. For brown dwarfs below T eff ~ 450 K, water condenses in the upper atmosphere to form ice clouds. Currently, over a dozen objects in this temperature range have been discovered, and few previous theoretical studies have addressed the effect of water clouds on brown dwarf or exoplanetary spectra. Here we present a new grid of models that include the effect of water cloud opacity. We find that they become optically thick in objects below T eff ~ 350-375 K. Unlike refractory cloud materials, water-ice particles are significantly nongray absorbers; they predominantly scatter at optical wavelengths through the J band and absorb in the infrared with prominent features, the strongest of which is at 2.8 ?m. H2O, NH3, CH4, and H2 CIA are dominant opacity sources; less abundant species may also be detectable, including the alkalis, H2S, and PH3. PH3, which has been detected in Jupiter, is expected to have a strong signature in the mid-infrared at 4.3 ?m in Y dwarfs around T eff = 450 K if disequilibrium chemistry increases the abundance of PH3, it may be detectable over a wider effective temperature range than models predict. We show results incorporating disequilibrium nitrogen and carbon chemistry and predict signatures of low gravity in planetary mass objects. Finally, we make predictions for the observability of Y dwarfs and planets with existing and future instruments, including the James Webb Space Telescope and Gemini Planet Imager.

Morley, Caroline V.; Marley, Mark S.; Fortney, Jonathan J.; Lupu, Roxana; Saumon, Didier; Greene, Tom; Lodders, Katharina

2014-05-01

383

A transiting giant planet with a temperature between 250K and 430K  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Of the over 400 known exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets, including the first terrestrial exoplanet (CoRoT-7b), have been discovered using a space mission designed to find smaller and more distant planets than can be seen from the ground. Here we report transit observations of CoRoT-9b, which orbits with a period ...

2010-01-01

384

Interactions between exoplanets and the winds of young stars  

Directory of Open Access Journals (Sweden)

Full Text Available The topology of the magnetic field of young stars is important not only for the investigation of magnetospheric accretion, but also responsible in shaping the large-scale structure of stellar winds, which are crucial for regulating the rotation evolution of stars. Because winds of young stars are believed to have enhanced mass-loss rates compared to those of cool, main-sequence stars, the interaction of winds with newborn exoplanets might affect the early evolution of planetary systems. This interaction can also give rise to observational signatures which could be used as a way to detect young planets, while simultaneously probing for the presence of their still elusive magnetic fields. Here, we investigate the interaction between winds of young stars and hypothetical planets. For that, we model the stellar winds by means of 3D numerical magnetohydrodynamic simulations. Although these models adopt simplified topologies of the stellar magnetic field (dipolar fields that are misaligned with the rotation axis of the star, we show that asymmetric field topologies can lead to an enhancement of the stellar wind power, resulting not only in an enhancement of angular momentum losses, but also intensifying and rotationally modulating the wind interactions with exoplanets.

Vidotto A. A.

2014-01-01

385

Terrestrial, Habitable-Zone Exoplanet Frequency from Kepler  

CERN Document Server

Data from Kepler's first 136 days of operation are analyzed to determine the distribution of exoplanets with respect to radius, period, and host-star spectral type. The analysis is extrapolated to estimate the percentage of terrestrial, habitable-zone exoplanets. The Kepler census is assumed to be complete for bright stars (magnitude 0.5 Earth radius and periods <42 days. It is also assumed that the size distribution of planets is independent of orbital period, and that there are no hidden biases in the data. Six significant statistical results are found: there is a paucity of small planet detections around faint target stars, probably an instrumental effect; the frequency of mid-size planet detections is independent of whether the host star is bright or faint; there are significantly fewer planets detected with periods <3 days, compared to longer periods, almost certainly an astrophysical effect; the frequency of all planets in the population with periods <42 days is 29%, broken down as terrestrials...

Traub, Wesley A

2011-01-01

386

Interactions between exoplanets and the winds of young stars  

Science.gov (United States)

The topology of the magnetic field of young stars is important not only for the investigation of magnetospheric accretion, but also responsible in shaping the large-scale structure of stellar winds, which are crucial for regulating the rotation evolution of stars. Because winds of young stars are believed to have enhanced mass-loss rates compared to those of cool, main-sequence stars, the interaction of winds with newborn exoplanets might affect the early evolution of planetary systems. This interaction can also give rise to observational signatures which could be used as a way to detect young planets, while simultaneously probing for the presence of their still elusive magnetic fields. Here, we investigate the interaction between winds of young stars and hypothetical planets. For that, we model the stellar winds by means of 3D numerical magnetohydrodynamic simulations. Although these models adopt simplified topologies of the stellar magnetic field (dipolar fields that are misaligned with the rotation axis of the star), we show that asymmetric field topologies can lead to an enhancement of the stellar wind power, resulting not only in an enhancement of angular momentum losses, but also intensifying and rotationally modulating the wind interactions with exoplanets.

Vidotto, A. A.; Opher, M.; Jatenco-Pereira, V.; Gombosi, T. I.

2014-01-01

387

Visible Nulling Coronagraphy Testbed Development for Exoplanet Detection  

Science.gov (United States)

Three of the recently completed NASA Astrophysics Strategic Mission Concept (ASMC) studies addressed the feasibility of using a Visible Nulling Coronagraph (VNC) as the prime instrument for exoplanet science. The VNC approach is one of the few approaches that works with filled, segmented and sparse or diluted aperture telescope systems and thus spans the space of potential ASMC exoplanet missions. NASA/Goddard Space Flight Center (GSFC) has a well-established effort to develop VNC technologies and has developed an incremental sequence of VNC testbeds to advance the this approach and the technologies associated with it. Herein we report on the continued development of the vacuum Visible Nulling Coronagraph testbed (VNT). The VNT is an ultra-stable vibration isolated testbed that operates under high bandwidth closed-loop control within a vacuum chamber. It will be used to achieve an incremental sequence of three visible light nulling milestones of sequentially higher contrasts of 10(exp 8) , 10(exp 9) and 10(exp 10) at an inner working angle of 2*lambda/D and ultimately culminate in spectrally broadband (>20%) high contrast imaging. Each of the milestones, one per year, is traceable to one or more of the ASMC studies. The VNT uses a modified Mach-Zehnder nulling interferometer, modified with a modified "W" configuration to accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters. Discussed will be the optical configuration laboratory results, critical technologies and the null sensing and control approach.

Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Thompson, Patrick; Chen, Andrew; Petrone, Peter; Booth, Andrew; Madison, Timothy; Bolcar, Matthew; Noecker, M. Charley; Kendrick, Stephen; Melnick, Gary; Tolls, Volker

2010-01-01

388

Kepler Exoplanet Candidate Host Stars are Preferentially Metal Rich  

CERN Document Server

We find that Kepler exoplanet candidate (EC) host stars are preferentially metal-rich, including the low-mass stellar hosts of small-radius ECs. The last observation confirms a tentative hint that there is a correlation between the metallicity of low-mass stars and the presence of low-mass and small-radius exoplanets. In particular, we compare the J-H--g-r color-color distribution of Kepler EC host stars with a control sample of dwarf stars selected from the ~150,000 stars observed during Q1 and Q2 of the Kepler mission but with no detected planets. We find that at J-H = 0.30 characteristic of solar-type stars, the average g-r color of stars that host giant ECs is 4-sigma redder than the average color of the stars in the control sample. At the same time, the average g-r color of solar-type stars that host small-radius ECs is indistinguishable from the average color of the stars in the control sample. In addition, we find that at J-H = 0.62 indicative of late K dwarfs, the average g-r color of stars that host ...

Schlaufman, Kevin C

2011-01-01

389

Biosignature Gases in H2-Dominated Atmospheres on Rocky Exoplanets  

CERN Multimedia

(Abridged) Super Earth exoplanets are being discovered with increasing frequency and some will be able to retain stable H2-dominated atmospheres. We study biosignature gases on exoplanets with thin H2 atmospheres and habitable surface temperatures, by using a model atmosphere with photochemistry, and biomass estimate framework for evaluating the plausibilty of a range of biosignature gas candidates. We find that photochemically produced H atoms are the most abundant reactive species in H2 atmospheres. In atmospheres with high CO2 levels, atomic O is the major destructive species for some molecules. In sun-Earth-like UV radiation environments, H (and in some cases O) will rapidly destroy nearly all biosignature gases of interest. The lower UV fluxes from UV quiet M stars would produce a lower concentration of H (or O) for the same scenario, enabling some biosignature gases to accumulate. The favorability of low-UV radiation environments to in an H2 atmosphere is closely analogous to the case of oxidized atmosp...

Seager, S; Hu, R

2013-01-01

390

MAGNETIC SCALING LAWS FOR THE ATMOSPHERES OF HOT GIANT EXOPLANETS  

International Nuclear Information System (INIS)

We present scaling laws for advection, radiation, magnetic drag, and ohmic dissipation in the atmospheres of hot giant exoplanets. In the limit of weak thermal ionization, ohmic dissipation increases with the planetary equilibrium temperature (Teq ?> 1000 K) faster than the insolation power does, eventually reaching values ?> 1% of the insolation power, which may be sufficient to inflate the radii of hot Jupiters. At higher Teq values still magnetic drag rapidly brakes the atmospheric winds, which reduces the associated ohmic dissipation power. For example, for a planetary field strength B = 10 G, the fiducial scaling laws indicate that ohmic dissipation exceeds 1% of the insolation power over the equilibrium temperature range Teq ? 1300-2000 K, with a peak contribution at Teq ? 1600 K. Evidence for magnetically dragged winds at the planetary thermal photosphere could emerge in the form of reduced longitudinal offsets for the dayside infrared hotspot. This suggests the possibility of an anticorrelation between the amount of hotspot offset and the degree of radius inflation, linking the atmospheric and interior properties of hot giant exoplanets in an observationally testable way. While providing a useful framework to explore the magnetic scenario, the scaling laws also reveal strong parameter dependencies, in particular with respect to the unknown planetary magnetic field strength.

2012-02-01

391

The Search for Stellar Companions to Exoplanet Host Stars Using the CHARA Array  

CERN Multimedia

Most exoplanets have been discovered via radial velocity studies, which are inherently insensitive to orbital inclination. Interferometric observations will show evidence of a stellar companion if it sufficiently bright, regardless of the inclination. Using the CHARA Array, we observed 22 exoplanet host stars to search for stellar companions in low-inclination orbits that may be masquerading as planetary systems. While no definitive stellar companions were discovered, it was possible to rule out certain secondary spectral types for each exoplanet system observed by studying the errors in the diameter fit to calibrated visibilities and by searching for separated fringe packets.

Baines, Ellyn K; Brummelaar, Theo A ten; Turner, Nils H; Sturmann, Judit; Sturmann, Laszlo; Ridgway, Stephen T

2008-01-01

392

The transmission spectrum of Earth-size transiting planets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A variety of terrestrial planets with different physical parameters and exotic atmospheres might plausibly exist outside our Solar System, waiting to be detected by the next generation of space-exploration missions. Some of these planets might transit their parent star. We present here the first study of atmospheric signatures of transiting Earth-size exoplanets. We focus on a limited number of significant examples, for which we discuss the detectability of some of the possi...

Ehrenreich, David; Tinetti, Giovanna; Etangs, Alain Lecavelier Des; Vidal-madjar, Alfred; Selsis, Franck

2005-01-01

393

HD 40307b, the first transiting Super-Earth?  

Science.gov (United States)

We stand on a great divide in the history of exoplanet discoveries. On the one side are the Spitzer observations of hot Jupiters that have revolutionized the burgeoning field of exoplanet characterization. On the other side are the Earth analogs with surface temperatures suitable for liquid water. Spitzer has a tremendous opportunity to bridge the divide by detecting the first transiting Super-Earth. HD 40307 is a bright (V=7.2, K=4.8) nearby (12.8 pc) K2 dwarf with three newly-discovered very low-mass exoplanets (Mayor et al., 2008). The innermost planet has a minimum mass of 4.21 M_Earth. With a 4.3 day period, the transit probability is 8% if the orbital plane is randomly aligned. We propose 10.5 h of IRAC-ch4 in subarray mode to monitor HD 40307 during the expected transit time. The first detection of a transiting Super-Earth would enable the first robust identification of a terrestrial-like exoplanet. With a measured radius and mass, the interior composition of the planet can be constrained. Spitzer is the only existing instrument able to perform this challenging detection. There is furthermore a compelling reason to conduct this particular search now, while Spitzer still has cryogen. This system is very favorable for observation (being only 12 pc distant), and a temperature measurement for the Super-Earth---by detection of the secondary eclipse---will be possible, once a transit is confirmed. Due to the nearly 40-degree orbital coverage we will obtain, our proposed observations will teach us about the presence and properties of the planet's atmosphere eve