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1

WASP-34b: a near-grazing transiting sub-Jupiter-mass exoplanet in a hierarchical triple system  

Science.gov (United States)

We report the discovery of WASP-34b, a sub-Jupiter-mass exoplanet transiting its 10.4-magnitude solar-type host star (1SWASP J110135.89-235138.4; TYC 6636-540-1) every 4.3177 days in a slightly eccentric orbit (e = 0.038±0.012). We find a planetary mass of 0.59±0.01 MJup and radius of 1.22-0.08+0.11 RJup. There is a linear trend in the radial velocities of 55±4 m s-1 y-1 indicating the presence of a long-period third body in the system with a mass ?0.45 MJup at a distance of ?1.2 AU from the host star. This third-body is either a low-mass star, a white dwarf, or another planet. The transit depth ((RP/Rstar)2 = 0.0126) and high impact parameter (b = 0.90) suggest that this could be the first known transiting exoplanet expected to undergo grazing transits, but with a confidence of only 80%. Radial velocity and photometric data are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/526/A130

Smalley, B.; Anderson, D. R.; Collier Cameron, A.; Hellier, C.; Lendl, M.; Maxted, P. F. L.; Queloz, D.; Triaud, A. H. M. J.; West, R. G.; Bentley, S. J.; Enoch, B.; Gillon, M.; Lister, T. A.; Pepe, F.; Pollacco, D.; Segransan, D.; Smith, A. M. S.; Southworth, J.; Udry, S.; Wheatley, P. J.; Wood, P. L.; Bento, J.

2011-02-01

2

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

3

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 TRAPP...

Smalley, B; Anderson, D R; Collier-Cameron, A; Doyle, A P; Gillon, Michaël; Hellier, C; Jehin, Emmanuel; Lendl, M; Maxted, P F L

4

Transiting Exoplanets with JWST  

CERN Multimedia

The era of exoplanet characterization is upon us. For a subset of exoplanets -- the transiting planets -- physical properties can be measured, including mass, radius, and atmosphere characteristics. Indeed, measuring the atmospheres of a further subset of transiting planets, the hot Jupiters, is now routine with the Spitzer Space Telescope. The James Webb Space Telescope (JWST) will continue Spitzer's legacy with its large mirror size and precise thermal stability. JWST is poised for the significant achievement of identifying habitable planets around bright M through G stars--rocky planets lacking extensive gas envelopes, with water vapor and signs of chemical disequilibrium in their atmospheres. Favorable transiting planet systems, are, however, anticipated to be rare and their atmosphere observations will require tens to hundreds of hours of JWST time per planet. We review what is known about the physical characteristics of transiting planets, summarize lessons learned from Spitzer high-contrast exoplanet m...

Seager, S; Valenti, J A

2008-01-01

5

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

6

HAT-P-28b and HAT-P-29b: Two Sub-Jupiter Mass Transiting Planets  

CERN Document Server

We present the discovery of two transiting exoplanets. HAT-P-28b orbits a V=13.03 G3 dwarf star with a period P = 3.2572 d and has a mass of 0.63 +- 0.04 MJ and a radius of 1.21 + 0.11 -0.08 RJ yielding a mean density of 0.44 +- 0.09 g cm-3. HAT-P-29b orbits a V=11.90 F8 dwarf star with a period P = 5.7232 d and has a mass of 0.78 +0.08 -0.04 MJ and a radius of 1.11 +0.14 -0.08 RJ yielding a mean density of 0.71 +- 0.18 g cm-3. We discuss the properties of these planets in the context of other known transiting planets.

Buchhave, L A; Hartman, J D; Torres, G; Latham, D W; Andersen, J; Kovacs, G; Noyes, R W; Shporer, A; Esquerdo, G A; Fischer, D A; Johnson, J A; Marcy, G W; Howard, A W; Beky, B; Sasselov, D D; Furesz, G; Quinn, S N; Stefanik, R P; Szklenar, T; Berlind, P; Calkins, M L; Lazar, J; Papp, I; Sari, P

2011-01-01

7

Young Exoplanet Transit Initiative (YETI)  

CERN Multimedia

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

8

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

9

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

10

TERMS Photometry of Known Transiting Exoplanets  

CERN Document Server

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

11

The observation of exoplanet transit events in China  

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Wang X.-B.; Gu S.-H.; Collier Cameron A.; Fang X.-S.

2011-01-01

12

The Young Exoplanet Transit Initiative (YETI)  

Science.gov (United States)

We present the Young Exoplanet Transit Initiative (YETI), in which we use several 0.2 to 2.6-m 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 millimag 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 cluster. If we observe ˜10 similar clusters, we can expect to detect ˜10 young transiting planets with radius determinations. The precision given above is for a typical telescope of the YETI network, namely the 60/90-cm Jena telescope (similar brightness limit, namely within ± 1 mag, for the others) so that planetary transits can be detected. For targets with a periodic transit-like light curve, we obtain spectroscopy to ensure that the star is young and that the transiting object can be sub-stellar; then, we obtain Adaptive Optics infrared images and spectra, to exclude other bright eclipsing stars in the (larger) optical PSF; we carry out other observations as needed to rule out other false positive scenarios; finally, we also perform spectroscopy to determine the mass of the transiting companion. For planets with mass and radius determinations, we can calculate the mean density and probe the internal structure. We aim to constrain planet formation models and their time-scales by discovering planets younger than ˜100 Myr and determining not only their orbital parameters, but also measuring their true masses and radii, which is possible so far only by the transit method. Here, we present an overview and first results.

Neuhäuser, R.; Errmann, 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.; Kjurkchieva, D. P.; Radeva, 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.; Eisenbeiß, 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.

2011-07-01

13

Transiting exoplanets: From planet statistics to their physical nature  

Directory of Open Access Journals (Sweden)

Full Text Available 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 detections and investigations discussed at this meeting.

Rauer H.

2011-01-01

14

Parametrized post-Newtonian secular transit timing variations for exoplanets  

Science.gov (United States)

Ground-based and space-borne observatories used for studying exoplanet transits now and in the future will considerably increase the number of exoplanets known from transit data 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 to test the general theory of relativity in these systems. To build a framework for these possible tests, we extend previous studies on the observability of the general relativistic precessions of periastron in transiting exoplanets to variations in secular transit timing under parametrized post-Newtonian formalism. We find that if one can measure the difference between observed and predicted variations of general relativistic secular transit timing to 1 s yr-1 in a transiting exoplanet system with a Sun-like mass, a period of ~ 1 day and a relatively small eccentricity of ~ 0.1, general relativity will be tested to the level of ~ 6%.

Zhao, Shan-Shan; Xie, Yi

2013-10-01

15

TASTE: The Asiago Survey for Timing transit variations of Exoplanets  

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 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

16

Transit timing variation in exoplanet WASP-3b  

Science.gov (United States)

Photometric follow-ups of transiting exoplanets 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. We present photometric observations gathered in 2009 and 2010 for exoplanet WASP-3b during the dedicated transit-timing-variation campaign. The observed transit timing cannot be explained by a constant period but by a periodic variation in the observations minus calculations diagram. Simplified models assuming the existence of a perturbing planet in the system and reproducing the observed variations of timing residuals were identified by three-body simulations. We found that the configuration with the hypothetical second planet of mass ~, located close to the outer 2:1 mean-motion resonance, is the most likely scenario reproducing observed transit timing. We emphasize, however, that more observations are required to constrain better the parameters of the hypothetical second planet in the WASP-3 system. For final interpretation not only transit timing but also photometric observations of the transit of the predicted second planet and high-precision radial velocity data are needed. This paper is based on observations made with the 60-cm telescope of the Rozhen National Astronomical Observatory, which is operated by the Institute of Astronomy, Bulgarian Academy of Sciences, and the 90-cm telescope of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich Schiller University. E-mail: gm@astro.uni-jena.de

Maciejewski, G.; Dimitrov, D.; Neuhäuser, R.; Niedzielski, A.; Raetz, St.; Ginski, Ch.; Adam, Ch.; Marka, C.; Moualla, M.; Mugrauer, M.

2010-10-01

17

Using color photometry to separate transiting exoplanets from false positives  

CERN Multimedia

The radial velocity technique is currently used to classify transiting objects. While capable of identifying grazing binary eclipses, this technique cannot reliably identify blends, a chance overlap of a faint background eclipsing binary with an ordinary foreground star. Blends generally have no observable radial velocity shifts, as the foreground star is brighter by several magnitudes and therefore dominates the spectrum, but their combined light can produce events that closely resemble those produced by transiting exoplanets. The radial velocity technique takes advantage of the mass difference between planets and stars to classify exoplanet candidates. However, the existence of blends renders this difference an unreliable discriminator. Another difference must therefore be utilized for this classification -- the physical size of the transiting body. Due to the dependence of limb darkening on color, planets and stars produce subtly different transit shapes. These differences can be relatively weak, little mo...

Tingley, B

2004-01-01

18

Five Kepler target stars that show multiple transiting exoplanet candidates  

CERN Document Server

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 multitransiting systems have on the distribution of orbital inclinations in planetary systems, and hence their dynamical histories; as well as their likely masses and chemical compos...

Steffen, Jason H; Borucki, William J; Buchhave, Lars A; Caldwell, Douglas A; Cochran, William D; Endl, Michael; Fabrycky, Daniel C; Fressin, François; Ford, Eric B; Fortney, Jonathan J; Haas, Michael J; Holman, Matthew J; Isaacson, Howard; Jenkins, Jon M; Koch, David; Latham, David W; Lissauer, Jack J; Moorhead, Althea V; Morehead, Robert C; Marcy, Geoffrey; MacQueen, Phillip J; Quinn, Samuel N; Ragozzine, Darin; Rowe, Jason F; Sasselov, Dimitar D; Seager, Sara; Torres, Guillermo; Welsh, William F

2010-01-01

19

Detection of transiting Jovian exoplanets by Gaia photometry - expected yield  

CERN Document Server

Several attempts have been made in the past to assess the expected number of exoplanetary transits that the Gaia space mission will detect. In this Letter we use the updated design of Gaia and its expected performance, and apply recent empirical statistical procedures to provide a new assessment. Depending on the extent of the follow-up effort that will be devoted, we expect Gaia to detect a few hundreds to a few thousands transiting exoplanets.

Dzigan, Yifat

2012-01-01

20

The NStED Exoplanet Transit Survey Service  

CERN Multimedia

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 latter component: the NStED Exoplanet Transit Survey Service (NStED-ETSS), along with its content, functionality, tools, and user interface. 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 community by archiving these data and making them available in a homogeneous format. Examples of usability of ETSS include investigation of any time-variable phenomena in data sets not stud...

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

2008-01-01

 
 
 
 
21

NStED: Exo-Planet Transit Survey KELT Praesepe  

Science.gov (United States)

The Kilodegree Extremely Little Telescope (KELT) project is a survey for planetary transits of bright stars. It consists of a small-aperture, wide-field automated telescope located at Winer Observatory near Sonoita, Arizona. The telescope surveys a set of 26 degrees by 26 degrees fields that together cover about 25% of the northern sky, and targets stars in the range of 8 < V < 10 mag, searching for transits by close-in Jupiters. The NASA/IPAC/NExScI Star and Exoplanet Database (NStED) provides access to high precision time-series photometry from stars observed by various exoplanet transit and photometric variability survey programs. The KELT-Praesepe data presented here are the result of commissioning campaign with KELT telescope to observe the open cluster Praesepe for 34 nights in early 2005.

Pepper, Joshua; Stanek, K. Z.; Pogge, Richard W.; Latham, David W.; Depoy, D. L.; Siverd, Robert; Poindexter, Shawn; Sivakoff, Gregory R.

22

The low density transiting exoplanet WASP-15b  

CERN Multimedia

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+-0.0000028d has a mass M_p=0.542+-0.050M_J and radius R_p=1.428+-0.077R_J, and is therefore the one of least dense transiting exoplanets so far discovered (rho_p=0.247+-0.035g 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+-100K and [Fe/H]=-0.17+-0.11.

West, R G; Gillon, M; Hebb, L; Hellier, C; Maxted, P F L; Queloz, D; Smalley, B; Triaud, A H M J; Wilson, D M; Bentley, S J; Cameron, A Collier; Enoch, B; Horne, K; Irwin, J; Lister, T A; Mayor, M; Parley, N; Pepe, F; Pollacco, D; Ségransan, D; Udry, S; Wheatley, P J

2009-01-01

23

KELT-1b: A Strongly Irradiated, Highly Inflated, Short Period, 27 Jupiter-mass Companion Transiting a mid-F Star  

CERN Document Server

We present the discovery of KELT-1b, the first transiting low-mass companion from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North) survey. The V=10.7 primary is a mildly evolved, solar-metallicity, mid-F star. The companion is a low-mass brown dwarf or super-massive planet with mass of 27.23+/-0.50 MJ and radius of 1.110+0.037-0.024 RJ, on a very short period (P=1.21750007) circular orbit. KELT-1b receives a large amount of stellar insolation, with an equilibrium temperature assuming zero albedo and perfect redistribution of 2422 K. Upper limits on the secondary eclipse depth indicate that either the companion must have a non-zero albedo, or it must experience some energy redistribution. Comparison with standard evolutionary models for brown dwarfs suggests that the radius of KELT-1b is significantly inflated. Adaptive optics imaging reveals a candidate stellar companion to KELT-1, which is consistent with an M dwarf if bound. The projected spin-orbit alignment angle is consistent with ...

Siverd, Robert J; Pepper, Joshua; Eastman, Jason D; Collins, Karen; Bieryla, Allyson; Latham, David W; Buchhave, Lars A; Jensen, Eric L N; Crepp, Justin R; Street, Rachel; Stassun, Keivan G; Gaudi, B Scott; Berlind, Perry; Calkins, Michael L; DePoy, D L; Esquerdo, Gilbert A; Fulton, Benjamin J; Furesz, Gabor; Geary, John C; Gould, Andrew; Hebb, Leslie; Kielkopf, John F; Marshall, Jennifer L; Pogge, Richard; Stanek, K Z; Stefanik, Robert P; Szentgyorgyi, Andrew H; Trueblood, Mark; Trueblood, Patricia; Stutz, Amelia M; van Saders, Jennifer L

2012-01-01

24

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 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.

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

2010-01-01

25

Five Kepler target stars that show multiple transiting exoplanet candidates  

Energy Technology Data Exchange (ETDEWEB)

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 multitransiting 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 (TTV) 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.; /Fermilab; Batalha, Natalie M.; /San Jose State U.; Borucki, William J.; /NASA, Ames; Buchhave, Lars A.; /Harvard-Smithsonian Ctr. Astrophys. /Bohr Inst.; Caldwell, Douglas A.; /NASA, Ames /SETI Inst., Mtn. View; Cochran, William D.; /Texas U.; Endl, Michael; /Texas U.; Fabrycky, Daniel C.; /Harvard-Smithsonian Ctr. Astrophys.; Fressin, Francois; /Harvard-Smithsonian Ctr. Astrophys.; Ford, Eric B.; /Florida U.; Fortney, Jonathan J.; /UC, Santa Cruz, Phys. Dept. /NASA, Ames

2010-06-01

26

TRANSIT TIMING VARIATIONS FOR ECCENTRIC AND INCLINED EXOPLANETS  

International Nuclear Information System (INIS)

[en] The Transit Timing Variation (TTV) method relies on monitoring changes in timing of transits of known exoplanets. Nontransiting planets in the system can be inferred from TTVs by their gravitational interactions with the transiting planet. The TTV method is sensitive to low-mass planets that cannot be detected by other means. Inferring the orbital elements and mass of the nontransiting planets from TTVs, however, is more challenging than for other planet detection schemes. It is a difficult inverse problem. Here, we extended the new inversion method proposed by Nesvorny and Morbidelli to eccentric transiting planets and inclined orbits. We found that the TTV signal can be significantly amplified for hierarchical planetary systems with substantial orbital inclinations and/or for an eccentric transiting planet with anti-aligned orbit of the planetary companion. Thus, a fortuitous orbital setup of an exoplanetary system may significantly enhance our chances of TTV detection. We also showed that the detailed shape of the TTV signal is sensitive to the orbital inclination of the nontransiting planetary companion. The TTV detection method may thus provide important constraints on the orbital inclination of exoplanets and be used to test theories of planetary formation and evolution.

2009-08-20

27

Transit Timing Variations for Eccentric and Inclined Exoplanets  

Science.gov (United States)

The Transit Timing Variation (TTV) method relies on monitoring changes in timing of transits of known exoplanets. Nontransiting planets in the system can be inferred from TTVs by their gravitational interactions with the transiting planet. The TTV method is sensitive to low-mass planets that cannot be detected by other means. Inferring the orbital elements and mass of the nontransiting planets from TTVs, however, is more challenging than for other planet detection schemes. It is a difficult inverse problem. Here, we extended the new inversion method proposed by Nesvorný & Morbidelli to eccentric transiting planets and inclined orbits. We found that the TTV signal can be significantly amplified for hierarchical planetary systems with substantial orbital inclinations and/or for an eccentric transiting planet with anti-aligned orbit of the planetary companion. Thus, a fortuitous orbital setup of an exoplanetary system may significantly enhance our chances of TTV detection. We also showed that the detailed shape of the TTV signal is sensitive to the orbital inclination of the nontransiting planetary companion. The TTV detection method may thus provide important constraints on the orbital inclination of exoplanets and be used to test theories of planetary formation and evolution.

Nesvorný, David

2009-08-01

28

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

29

H? Absorption in Transiting Exoplanet Atmospheres  

Science.gov (United States)

Absorption of stellar H? 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? 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? absorption is dominated by an optical depth ? ~ 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? absorption, for a certain wavelength, occurs inside a relatively well defined impact parameter, the contribution to H? absorption is roughly uniform over the entire atomic hydrogen layer. The model can approximately reproduce the observed Ly? and H? 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? 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? absorption on the net cooling rate.

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

2013-08-01

30

Optical Observations of the Transiting Exoplanet GJ 1214b  

CERN Document Server

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 (0.65 {\\mu}m), V (0.55 {\\mu}m), and g' (0.475 {\\mu}m) bands. Most previous observations of this exoplanet suggest a flat spectrum varying little with wavelength from the near-infrared to the optical, corresponding to a low-scale-height, high-molecular-weight atmosphere. However, a handful of observations around Ks band (~2.15 {\\mu}m) and g-band (~0.46 {\\mu}m) are inconsistent with this scenario and suggest a variation on a hydrogen- or water-dominated atmosphere that also contains a haze layer of small particles. In particular, the g-band observations of de Mooij et al. (2012), consistent with Ray...

Teske, Johanna K; Mueller, Matthias; Griffith, Caitlin A

2013-01-01

31

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, l...

Tingley, B.; Endl, M.; Gazzano, J*-C; Alonso, R.; Mazeh, T.; Jorda, L.; Aigrain, S.; Almenara, J*-M; Auvergne, M.; Baglin, A.

32

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

CERN Multimedia

In this paper, the CoRoT Exoplanet Science 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 $7.6 \\pm 0.6$ 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 exoplanet with a higher mass orbits with a shorter period.

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

2011-01-01

33

On the Possibility of Detecting Class A Stellar Engines Using Exoplanet Transit Curves  

CERN Multimedia

The Class A stellar engine (also known as a Shkadov thruster) is a spherical arc mirror, designed to use the impulse from a star's radiation pressure to generate a thrust force, perturbing the star's motion. If this mirror obstructs part of the stellar disc during the transit of an exoplanet, then this may be detected by studying the shape of the transit light curve, presenting another potential means by which the action of extraterrestrial intelligence (ETI) can be discerned. We model the light curves produced by exoplanets transiting a star which possesses a Shkadov thruster, and show how the parameters of the planet and the properties of the thruster can be disentangled. provided that radial velocity follow-up measurements are possible, and that other obscuring phenomena typical to exoplanet transit curves (such as the presence of starspots or intrinsic stellar noise) do not dominate. These difficulties aside, we estimate the a priori probability of detecting a Shkadov thruster during an exoplanet transit,...

Forgan, Duncan H

2013-01-01

34

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

CERN Document Server

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 Maciejewski's proposed sinusoidal signal.

Littlefield, Colin

2011-01-01

35

Transmission spectrum of Venus as a transiting exoplanet  

CERN Document Server

On 5-6 June 2012, Venus will be transiting the Sun for the last time before 2117. This event is an unique opportunity to assess the feasibility of the atmospheric characterisation of Earth-size exoplanets near the habitable zone with the transmission spectroscopy technique and provide an invaluable proxy for the atmosphere of such a planet. In this letter, we provide a theoretical transmission spectrum of the atmosphere of Venus that could be tested with spectroscopic observations during the 2012 transit. This is done using radiative transfer across Venus' atmosphere, with inputs from in-situ missions such as Venus Express and theoretical models. The transmission spectrum covers a range of 0.1-5 {\\mu}m and probes the limb between 70 and 150 km in altitude. It is dominated in UV by carbon dioxide absorption producing a broad transit signal of ~20 ppm as seen from Earth, and from 0.2 to 2.7 {\\mu}m by Mie extinction (~5 ppm at 0.8 {\\mu}m) caused by droplets of sulfuric acid composing an upper haze layer above th...

Ehrenreich, David; Widemann, Thomas; Gronoff, Guillaume; Tanga, Paolo; Barthélemy, Mathieu; Lilensten, Jean; Etangs, Alain Lecavelier des; Arnold, Luc

2011-01-01

36

Planetary transits from CoRoT-Europe and exoplanets  

International Nuclear Information System (INIS)

CoRoT (COnvection, ROtation and planetary Transit) was launched successfully into a near-perfect orbit on 27 December 2006 and went through its verification phase until 2 April 2007 without incident. Indeed, this process went so well that scientific operations could commence on 2 February 2007. Under the management of the French space agency CNES and with a major partnership with ESA, Austria, Belgium, Brazil, Germany and Spain, COROT is the first satellite dedicated to the search for and study of planets external to the solar system, orbiting other stars, the so-called exoplanets. Further, it is designed to be able to detect for the first time planets as small as our own Earth. A second major objective is the study of acoustical waves permeating stars. All scientific specifications have already been verified or surpassed, and the exploitation phase (nominally 2.5 years) is ongoing. This paper reports the status of exo-planetary research within the emerging European plan for future space research. It reports the launch and initial phases of the CoRoT mission and details the prospects of this mission. CoRoT is thus put into the context of the Cosmic Vision plan.

2006-12-27

37

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

38

In Pursuit of New Worlds: Searches for and Studies of Transiting Exoplanets from Three Space-Based Observatories  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis presents studies of transiting exoplanets using observations gathered in large part from space, with the NASA EPOXI Mission, the Spitzer Space Telescope, and the Kepler Mission. The first part of this thesis describes searches for additional transiting planets in known exoplanet systems,...

Ballard, Sarah

39

Aristarchos RISE2: A Wide-Field Fast Imager for Exoplanet Transit Timing  

Science.gov (United States)

The detection of exoplanets is currently of great topical interest in astronomy. The Rapid Imager for Surveys of Exoplanets 2 (RISE2) camera will be built for exoplanet studies and in particular for detection of transit timing variations (TTV) induced by the presence of a third body in the system. It will be identical to RISE which has been running successfully on the 2m Liverpool Telescope since 2008 but modified for the 2.3m ARISTARCHOS telescope. For TTV work the RISE/LT combination is regularly producing timings with accuracy <10 seconds making it the best suited instrument for this work. Furthermore, RISE2/AT has the added benefit of being located at a significantly different longitude to the LT/RISE on La Palma, hence extending the transit coverage.

Boumis, P.; Pollacco, D.; Steele, I.; Meaburn, J.; Xilouris, E. M.; Katsiyannis, A. C.; Bode, M.; Bates, S. D.; Goudis, C. D.; Keenan, F. P.; Watson, C.

2010-07-01

40

The Transit Light Curve (TLC) Project. VI. Three Transits of the Exoplanet TrES-2  

Science.gov (United States)

Of the nearby transiting exoplanets that are amenable to detailed study, TrES-2 is both the most massive and the one with the largest impact parameter. We present z-band photometry of three transits of TrES-2. We improve on the estimates of the planetary, stellar, and orbital parameters, in conjunction with the spectroscopic analysis of the host star by Sozzetti and coworkers. We find the planetary radius to be Rp=1.222+/-0.038 RJup and the stellar radius to be R*=1.003+/-0.027 Rsolar. The quoted uncertainties include the systematic error due to the uncertainty in the stellar mass (M*=0.980+/-0.062 Msolar). The timings of the transits have an accuracy of 25 s and are consistent with a uniform period, thus providing a baseline for future observations with the NASA Kepler satellite, whose field of view will include TrES-2.

Holman, Matthew J.; Winn, Joshua N.; Latham, David W.; O'Donovan, Francis T.; Charbonneau, David; Torres, Guillermo; Sozzetti, Alessandro; Fernandez, Jose; Everett, Mark E.

2007-08-01

 
 
 
 
41

The Young Exoplanet Transit Initiative (YETI) and results from the Bulgarian participation  

Science.gov (United States)

The paper presents the ideas of the international initiative YETI (Young Exoplanet Transit Initiative) for searching for young exoplanets in open clusters, information about the organization of the observational campaigns as well as the preliminary results from the observations of the first cluster Tr 37. It is noted the successful participation of the Bulgarian team in the observational campaigns of Tr 37 (27 observational nights with above 12000 images). Due to the interesting light curves of Tr 37-3132 obtained by the Rozhen telescopes this object was chosen for follow-up spectral observations with large telescopes in the framework of YETI.

Dimitrov, D.; Neuhäuser, R.; Kjurkchieva, D.; YETI Team

42

DETECTION OF TRANSITING JOVIAN EXOPLANETS BY GAIA PHOTOMETRY-EXPECTED YIELD  

Energy Technology Data Exchange (ETDEWEB)

Several attempts have been made in the past to assess the expected number of exoplanetary transits that the Gaia space mission will detect. In this Letter, we use the updated design of Gaia and its expected performance and apply recent empirical statistical procedures to provide a new assessment. Depending on the extent of the follow-up effort that will be devoted, we expect Gaia to detect from a few hundreds to a few thousands of transiting exoplanets.

Dzigan, Yifat; Zucker, Shay, E-mail: yifatdzigan@gmail.com, E-mail: shayz@post.tau.ac.il [Department of Geophysical, Atmospheric, and Planetary Sciences, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)

2012-07-01

43

Transit timing, depth, and duration variation in exoplanet TrES-2?  

Directory of Open Access Journals (Sweden)

Full Text Available We report on our ongoing search for timing, duration, and depth variations in the exoplanet TrES-2. In Raetz et al. (2009) we already presented ten di?erent transits obtained at the University Observatory Jena. Between November 2008 and August 2010 twelve additional transits could be observed. The timing, depth and duration of each individual event was analyzed and is presented here.

Raetz St.; Maciejewski G.; Mugrauer M.; Schmidt T.O.B.; Roell T.; Eisenbeiss T.; Berndt A.; Hohle M.M.; Ginski Ch.; Errmann R.; Seeliger M.; Adam Ch.; Pribulla T.; Tetzla? N.; Va?ko M.; Koppenhoefer J.; Raetz M.; Neuhäuser R.

2011-01-01

44

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

45

Validating and Characterizing Transiting Exoplanets from Space with EPOXI, Kepler, and Warm Spitzer  

Science.gov (United States)

My thesis work comprises analyses of transiting exoplanets with observations from three space-based instruments. The Extrasolar Planet Observation and Characterization (EPOCh) component of the EPOXI mission repurposed the Deep Impact Spacecraft to gather photometry of six known transiting exoplanet systems. I systematically searched the EPOXI light curves for additional transiting planets, and identified one such candidate in the exoplanet system GJ 436. I gathered Warm Spitzer light curves of GJ 436 during a predicted transit of this putative planet: while I ruled out the presence of the hypothesized planet, I developed a novel reduction technique for Warm Spitzer observations and demonstrated the sensitivity of that instrument to sub-Earth-sized transiting planets. I next applied these techniques to a sample of super-Earth-sized planetary candidates identified by the Kepler mission. In the absence of radial velocity confirmation (challenging for such low-mass planets), it is nonetheless possible to make a statistical argument for the planetary nature of the candidate, if the combined likelihood of all false positive scenarios is sufficiently smaller than the planet scenario. An authentic planet will exhibit an achromatic transit depth, as measured in the optical with Kepler and near-infrared with Warm Spitzer. The eclipse from a stellar blend, in contrast, would likely vary with wavelength. I presented the discovery of the Kepler-19 system, applying Warm Spitzer observations toward validation of the transiting 2.2 REarth planet, Kepler-19b. I identified systematic variations in the transit times of Kepler-19b, which led to the first robust detection of a non-transiting planet using the transit timing variation method: Kepler-19c. Support for EPOXI was provided by NASA's Discovery Program via Agreement NNX08AB64A. This work is based on observations made with the Spitzer Space Telescope. Support for Spitzer observations is provided by NASA through an award issued by JPL/Caltech.

Ballard, Sarah

2012-01-01

46

The Transit Light Curve (TLC) Project. I. Four Consecutive Transits of the Exoplanet XO-1b  

CERN Multimedia

We present RIz photometry of four consecutive transits of the newly discovered exoplanet XO-1b. We improve upon the estimates of the transit parameters, finding the planetary radius to be R_P = 1.184 +0.028/-0.018 R_Jupiter and the stellar radius to be R_S = 0.928 +0.018/-0.013 R_Sun, assuming a stellar mass of M_S = 1.00 +/- 0.03 M_Sun. The uncertainties in the planetary and stellar radii are dominated by the uncertainty in the stellar mass. These uncertainties increase by a factor of 2-3 if a more conservative uncertainty of 0.10 M_Sun is assumed for the stellar mass. Our estimate of the planetary radius is smaller than that reported by McCullough et al. (2006) and yields a mean density that is comparable to that of TrES-1 and HD 189733b. The timings of the transits have an accuracy ranging from 0.2 to 2.5 minutes, and are marginally consistent with a uniform period.

Holman, M J; Latham, D W; O'Donovan, F T; Charbonneau, D; Bakos, G A; Esquerdo, G A; Hergenrother, C; Everett, M E; Pal, A; Holman, Matthew J.; Winn, Joshua N.; Latham, David W.; Donovan, Francis T. O'; Charbonneau, David; Bakos, Gaspar A.; Esquerdo, Gilbert A.; Hergenrother, Carl; Everett, Mark E.; Pal, Andras

2006-01-01

47

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

48

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

CERN Multimedia

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

49

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

Science.gov (United States)

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 European Southern Observatory 3.5-m New Technology Telescope at La Silla. Typically, a sensitivity to companions of magnitude difference ?z' ? 4 is achieved at angular separation ? = 0.5 arcsec and ?z' ? 6 for ? = 1 arcsec. 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 companion candidates 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 that the binary separation is on average larger for planet host stars.

Bergfors, C.; Brandner, W.; Daemgen, S.; Biller, B.; Hippler, S.; Janson, M.; Kudryavtseva, N.; Geißler, K.; Henning, T.; Köhler, R.

2013-01-01

50

Limits on the Orbits and Masses of Moons around Currently-Known Transiting Exoplanets  

CERN Multimedia

Aims. Current and upcoming space missions may be able to detect moons of transiting extra-solar planets. In this context it is important to understand if exomoons are expected to exist and what their possible properties are. Methods. Using estimates for the stability of exomoon orbits from numerical studies, a list of 87 known transiting exoplanets is tested for the potential to host large exomoons. Results. For 92% of the sample, moons larger than Luna can be excluded on prograde orbits, unless the parent exoplanet's internal structure is very different from the gas-giants of the solar system. Only WASP-24b, OGLE2-TR-L9, CoRoT-3b and CoRoT-9b could have moons above 0.4 m\\oplus, which is within the likely detection capabilities of current observational facilities. Additionally, the range of possible orbital radii of exomoons of the known transiting exoplanets, with two exceptions, is below 8 Jupiter-radii and therefore rather small.

Weidner, Carsten

2010-01-01

51

EVIDENCE OF POSSIBLE SPIN-ORBIT MISALIGNMENT ALONG THE LINE OF SIGHT IN TRANSITING EXOPLANET SYSTEMS  

International Nuclear Information System (INIS)

Of the 26 transiting exoplanet systems with measurements of the Rossiter-McLaughlin (RM) effect, eight have now been found to be significantly spin-orbit misaligned in the plane of the sky (i.e., RM misalignment angle |?| ?> 300 and inconsistent with ? = 00). Unfortunately, the RM effect does not constrain the complement misalignment angle between the orbit of the planet and the spin of its host star along the line of sight (LOS). I use a simple model of stellar rotation benchmarked with observational data to statistically identify 10 exoplanet systems from a sample of 75 for which there is likely a significant degree of spin-orbit misalignment along the LOS: HAT-P-7, HAT-P-14, HAT-P-16, HD 17156, Kepler-5, Kepler-7, TrES-4, WASP-1, WASP-12, and WASP-14. All 10 systems have host stellar masses M * in the range 1.2 M sun ?* ?sun, and the probability of this occurrence by chance is less than one in ten thousand. In addition, the planets in the candidate-misaligned systems are preferentially massive and eccentric. The coupled distribution of misalignment from the RM effect and from this analysis suggests that transiting exoplanets are more likely to be spin-orbit aligned than expected given predictions for a transiting planet population produced entirely by planet-planet scattering or Kozai cycles and tidal friction. For that reason, there are likely two populations of close-in exoplanet systems: a population of aligned systems and a population of apparently misaligned systems in which the processes that lead to misalignment or to the survival of misaligned systems operate more efficiently in systems with massive stars and planets.

2010-08-10

52

OBSERVATIONS OF MASS LOSS FROM THE TRANSITING EXOPLANET HD 209458b  

International Nuclear Information System (INIS)

Using the new Cosmic Origins Spectrograph on the Hubble Space Telescope, we obtained moderate-resolution, high signal/noise ultraviolet spectra of HD 209458 and its exoplanet HD 209458b during transit, both orbital quadratures, and secondary eclipse. We compare transit spectra with spectra obtained at non-transit phases to identify spectral features due to the exoplanet's expanding atmosphere. We find that the mean flux decreased by 7.8% ± 1.3% for the C II 1334.5323 A and 1335.6854 A lines and by 8.2% ± 1.4% for the Si III 1206.500 A line during transit compared to non-transit times in the velocity interval -50 to +50 km s-1. Comparison of the C II and Si III line depths and transit/non-transit line ratios shows deeper absorption features near -10 and +15 km s-1 and less certain features near -40 and +30-70 km s-1, but future observations are needed to verify this first detection of velocity structure in the expanding atmosphere of an exoplanet. Our results for the C II lines and the non-detection of Si IV 1394.76 A absorption are in agreement with Vidal-Madjar et al., but we find absorption during transit in the Si III line contrary to the earlier result. The 8% ± 1% obscuration of the star during transit is far larger than the 1.5% obscuration by the exoplanet's disk. Absorption during transit at velocities between -50 and +50 km s-1 in the C II and Si III lines requires high-velocity ion absorbers. Assuming hydrodynamic model values for the gas temperature and outflow velocity at the limb of the outflow as seen in the C II lines, we find mass-loss rates in the range (8-40)x1010 g s-1. These rates assume that the carbon abundance is solar, which is not the case for the giant planets in the solar system. Our mass-loss rate estimate is consistent with theoretical hydrodynamic models that include metals in the outflowing gas.

2010-07-10

53

Improving Transit Predictions of Known Exoplanets with TERMS  

Directory of Open Access Journals (Sweden)

Full Text Available Transiting planet discoveries have largely been restricted to the short-period or low-periastron distance regimes due to the bias inherent in the geometric transit probability. Through the re?nement of planetary orbital parameters, and hence reducing the size of transit windows, long-period planets become feasible targets for photometric follow-up. Here we describe the TERMS project that is monitoring these host stars at predicted transit times.

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

2011-01-01

54

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

55

Exoplanet Transit Variability: Bow Shocks and Winds Around HD 189733b  

CERN Multimedia

By analogy with the solar system, it is believed that stellar winds will form bow shocks around exoplanets. For hot Jupiters the bow shock will not form directly between the planet and the star, causing an asymmetric distribution of mass around the exoplanet and hence an asymmetric transit. As the planet orbits thorough varying wind conditions, the strength and geometry of its bow shock will change, thus producing transits of varying shape. We model this process using magnetic maps of HD 189733 taken one year apart, coupled with a 3D stellar wind model, to determine the local stellar wind conditions throughout the orbital path of the planet. We predict the time-varying geometry and density of the bow shock that forms around the magnetosphere of the planet and simulate transit light curves. Depending on the nature of the stellar magnetic field, and hence its wind, we find that both the transit duration and ingress time can vary when compared to optical light curves. We conclude that consecutive near-UV transit...

Llama, J; Jardine, M; Wood, K; Fares, R; Gombosi, T I

2013-01-01

56

PHOTOMETRIC AND SPECTRAL SIGNATURES OF THREE-DIMENSIONAL MODELS OF TRANSITING GIANT EXOPLANETS  

International Nuclear Information System (INIS)

Using a three-dimensional general circulation model, we create dynamical model atmospheres of a representative transiting giant exoplanet, HD 209458b. We post-process these atmospheres with an opacity code to obtain transit radius spectra during the primary transit. Using a spectral atmosphere code, we integrate over the face of the planet seen by an observer at various orbital phases and calculate light curves as a function of wavelength and for different photometric bands. The products of this study are generic predictions for the phase variations of a zero-eccentricity giant planet's transit spectrum and of its light curves. We find that for these models the temporal variations in all quantities and the ingress/egress contrasts in the transit radii are small (

2010-08-10

57

Exoplanet transits in X-rays: a new observational window to the exoplanetary atmosphere  

Science.gov (United States)

Exoplanets in short-period orbits are subject to strong irradiation from their host star and can lose mass through evaporation. The main driver for this evaporation is high-energy emission from the host star. However, it is observationally unclear where in the exoplanetary atmosphere the bulk of the high-energy radiation is absorbed, and the energy budget for the evaporation is not well constrained. We have observed seven transits of the Hot Jupiter HD 189733 b in front of its host star, using X-ray observations with Chandra and XMM-Newton. We detect the exoplanetary transit in X-rays for the first time. We find a surprisingly large X-ray transit depth of 6-8%, in stark contrast to an optical transit depth of only 2.4%. We can trace this back to extended outer atmosphere layers of the planet which reach out to 1.75 optical planetary radii in altitude. We are able to derive density and temperature estimates for the outer planetary atmosphere, as well as a revised energy budget for planetary evaporation due to the large X-ray absorbing radius. These observations, together with accepted further programs in the X-ray regime, will allow us to build a comprehensive picture of the atmospheres of strongly irradiated exoplanets.

Poppenhaeger, Katja; Schmitt, J. H.; Wolk, S. J.

2013-10-01

58

TASTE: The Asiago Search for Transit timing variations of Exoplanets II. A new observational study of transit time variations in HAT-P-13b.  

Science.gov (United States)

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. It has been claimed that the hot jupiter HAT-P-13b suddenly deviated from a linear ephemeris by ~20min, implying that there is 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 hypothetical perturber. (1 data file).

Nascimbeni, V.; Piotto, G.; Bedin, L. R.; Damasso, M.; Malavolta, L.; Borsato, L.

59

GTC OSIRIS Transiting Exoplanet Atmospheric Survey: Detection of potassium in XO-2b from spectrophotometry  

CERN Multimedia

We present Gran Telescopio Canarias (GTC) optical transit narrow-band photometry of the hot-Jupiter exoplanet XO-2b using the OSIRIS instrument. This unique instrument has the capabilities to deliver high cadence narrow-band photometric lightcurves, allowing us to probe the atmospheric composition of hot Jupiters from the ground. The observations were taken during three transit events which cover four wavelengths at spectral resolutions near 500, necessary for observing atmospheric features, and have near-photon limited sub-mmag precisions. Precision narrow-band photometry on a large aperture telescope allows for atmospheric transmission spectral features to be observed for exoplanets around much fainter stars than those of the well studied targets HD209458b and HD189733b, providing access to the majority of known transiting planets. For XO-2b, we measure planet-to-star radius contrasts of R_pl/R_star=0.10508+/-0.00052 at 6792 Ang, 0.10640+/-0.00058 at 7582 Ang, and 0.10686+/-0.00060 at 7664.9 Ang, and 0.1036...

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

2010-01-01

60

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

 
 
 
 
61

Venus transit 2004: Illustrating the capability of exoplanet transmission spectroscopy  

CERN Multimedia

The transit of Venus in 2004 offered the rare possibility to remotely sense a well-known planetary atmosphere using ground-based observations for absorption spectroscopy. Transmission spectra of Venus' atmosphere were obtained in the near infrared using the Vacuum Tower Telescope (VTT) in Tenerife. Since the instrument was designed to measure the very bright photosphere of the Sun, extracting Venus' atmosphere was challenging. CO_2 absorption lines could be identified in the upper Venus atmosphere. Moreover, the relative abundance of the three most abundant CO_2 isotopologues could be determined. The observations resolved Venus' limb, showing Doppler-shifted absorption lines that are probably caused by high-altitude winds. This paper illustrates the ability of ground-based measurements to examine atmospheric constituents of a terrestrial planet atmosphere which might be applied in future to terrestrial extrasolar planets.

Hedelt, P; Brown, T; Vera, M Collados; Rauer, H; Schleicher, H; Schmidt, W; Schreier, F; Titz, R

2011-01-01

62

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

CERN Multimedia

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

63

The Transit Light Curve (TLC) Project. II. Two Transits of the Exoplanet OGLE-TR-111b  

CERN Document Server

As part of our ongoing effort to measure exoplanet sizes and transit times with greater accuracy, we present I band observations of two transits of OGLE-TR-111b. The photometry has an accuracy of 0.15-0.20% and a cadence of 1-2 minutes. We derive a planetary radius of 1.067 +/- 0.054 Jupiter radii and a stellar radius of 0.831 +/- 0.031 solar radii. The uncertainties are dominated by errors in the photometry, rather than by systematic errors arising from uncertainties in the limb darkening function or the stellar mass. Both the stellar radius and the planetary radius are in agreement with theoretical expectations. The transit times are accurate to within 30 seconds, and allow us to refine the estimate of the mean orbital period: 4.0144479 +/- 0.0000041 days.

Winn, J N; Fuentes, C I; Winn, Joshua N.; Holman, Matthew J.; Fuentes, Cesar I.

2006-01-01

64

Transmission spectrum of Earth as a transiting exoplanet - from the ultraviolet to the near-infrared  

CERN Multimedia

Transmission spectroscopy of exoplanets is a tool to characterize rocky planets and explore their habitability. Using the Earth itself as a proxy, we model the atmospheric cross section as a function of wavelength, and show the effect of each atmospheric species, Rayleigh scattering and refraction from 115 to 1000nm. Clouds do not significantly affect this picture because refraction prevents the lowest 12.75km of the atmosphere, in a transiting geometry for an Earth-Sun analog, to be sampled by a distant observer. We calculate the effective planetary radius for the primary eclipse spectrum of an Earth-like exoplanet around a Sun-like star. Below 200nm, ultraviolet(UV) O_2 absorption increases the effective planetary radius by about 180km, versus 27km at 760.3nm, and 14km in the near-infrared (NIR) due predominantly to refraction. This translates into a 2.6% change in effective planetary radius over the UV-NIR wavelength range, showing that the ultraviolet is an interesting wavelength range for future space mi...

Betremieux, Y

2013-01-01

65

RECENT TRANSITS OF THE SUPER-EARTH EXOPLANET GJ 1214b  

International Nuclear Information System (INIS)

We report recent ground-based photometry of the transiting super-Earth exoplanet GJ 1214b at several wavelengths, including the infrared near 1.25 ?m (J band). We observed a J-band transit with the FLAMINGOS infrared imager and the 2.1 m telescope on Kitt Peak, and we observed several optical transits using a 0.5 m telescope on Kitt Peak and the 0.36 m Universidad de Monterrey Observatory telescope. Our high-precision J-band observations exploit the brightness of the M dwarf host star at this infrared wavelength as compared with the optical and are significantly less affected by stellar activity and limb darkening. We fit the J-band transit to obtain an independent determination of the planetary and stellar radii. Our radius for the planet (2.61+0.30 -0.11 R +) is in excellent agreement with the discovery value reported by Charbonneau et al. based on optical data. We demonstrate that the planetary radius is insensitive to degeneracies in the fitting process. We use all of our observations to improve the transit ephemeris, finding P = 1.5804043 ± 0.0000005 days and T 0 = 2454964.94390 ± 0.00006 BJD.

2010-09-10

66

Photometric and Spectral Signatures of 3D Models of Transiting Giant Exoplanets  

CERN Multimedia

Using a 3D GCM, we create dynamical model atmospheres of a representative transiting giant exoplanet, HD 209458b. We post-process these atmospheres with an opacity code to obtain transit radius spectra during the primary transit. Using a spectral atmosphere code, we integrate over the face of the planet seen by an observer at various orbital phases and calculate light curves as a function of wavelength and for different photometric bands. The products of this study are generic predictions for the phase variations of a zero-eccentricity giant planet's transit spectrum and of its light curves. We find that for these models the temporal variations in all quantities and the ingress/egress contrasts in the transit radii are small ($< 1.0$\\%). Moreover, we determine that the day/night contrasts and phase shifts of the brightness peaks relative to the ephemeris are functions of photometric band. The $J$, $H$, and $K$ bands are shifted most, while the IRAC bands are shifted least. Therefore, we verify that the mag...

Burrows, Adam; Spiegel, David; Menou, Kristen

2010-01-01

67

The secondary eclipse of the transiting exoplanet CoRoT-2b  

CERN Document Server

We present a study of the light curve of the transiting exoplanet CoRoT-2b, aimed at detecting the secondary eclipse and measuring its depth. The data were obtained with the CoRoT satellite during its first run of more than 140 days. After filtering the low frequencies with a pre-whitening technique, we detect a 0.0060$\\pm$0.0020% secondary eclipse centered on the orbital phase 0.494$\\pm$0.006. Assuming a black-body emission of the planet, we estimate a surface brightness temperature of T$_{\\rm p,CoRoT}$=1910$^{+90}_{-100}$ K. We provide the planet's equilibrium temperature and re-distribution factors as a function of the unknown amount of reflected light. The upper limit for the geometric albedo is 0.12. The detected secondary is the shallowest ever found.

Alonso, R; Mazeh, T; Aigrain, S; Alapini, A; Barge, P; Hatzes, A; Pont, F

2009-01-01

68

Recent Transits of the Super-Earth Exoplanet GJ 1214b  

CERN Document Server

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 brightness of the M-dwarf host star at this infrared wavelength as compared to the optical, as well as being significantly less affected by stellar activity and limb darkening. We fit the J-band transit to obtain an independent determination of the planetary and stellar radii. Our radius for the planet (2.61^+0.30_-0.11 Earth radii) is in excellent agreement with the discovery value reported by Charbonneau et al. based on optical data. We demonstrate that the planetary radius is insensitive to degeneracies in the fitting process. We use all of our ...

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

2010-01-01

69

Asteroseismology of the Transiting Exoplanet Host HD 17156 with Hubble Space Telescope Fine Guidance Sensor  

DEFF Research Database (Denmark)

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 × 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 lang?*rang = 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 lang?*rang 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 M sun, R * = 1.507 ± 0.012 R sun, and a stellar age of 3.2 ± 0.3 Gyr. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.

Gilliland, Ronald L.; McCullough, Peter R.

2011-01-01

70

Expected Planet and False Positive Detection Rates for the Transiting Exoplanet Survey Satellite  

CERN Multimedia

The proposed Transiting Exoplanet Survey Satellite (TESS) will survey the entire sky to locate the nearest and brightest transiting extrasolar planets with orbital periods up to about 36 days. Here we estimate the number and kind of astrophysical false positives that TESS will report, along with the number of extrasolar planets. These estimates are then used to size the ground-based follow-up observing efforts needed to confirm and characterize the planets. We estimate that the needed observing resources will be about 1400 telescope-nights of imaging with 0.5m to 1m-class telescopes, 300 telescope-nights with 1m to 2m-class telescopes for the classification of the host stars and for radial velocity measurements with roughly 1 km/s precision, and 380 telescope-nights with 2m to 4m-class telescopes for radial velocity studies with precision of a few m/s. Follow-up spectroscopy of the smallest planets discovered by TESS at the best possible velocity precision will be limited by the number of telescope nights ava...

Brown, Timothy M

2008-01-01

71

Exploring the Potential of Transit Timing Variation (TTV) Observations of Exoplanets: Looking for Additional Planets  

Science.gov (United States)

Observations of variations in the time of an exoplanet transit can reveal the presence of additional planets. The sensitivity of "Transit Timing Variation" (TTV) observations varies dramatically depending on relative orbital configuration, but in a restricted phase space TTV observations could possibly discover lower mass planets than other current methods, perhaps even earth-mass planets. In 2006, I started the currently ongoing LCOGT TTV project to search for additional planets using the 2.0m FTN telescope on Haleakala, Maui, Hawaii. The images with which I started the project in 2006 will be presented. It will be shown that FTN needed improvement in order to do sufficiently accurate photometry. In 2006 Dec I moved to Maui and became the full-time onsite astronomer evaluating the telescope. I continued this work until 2007 March, when LCOGT determined that the major telescope problems were in software, and the data from the 2007 observations became unavailable. Expectations of what can be achieved by the further work will be discussed.

Taylor, Stuart F.

2008-03-01

72

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

CERN Multimedia

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 degree x 3.88 degree 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 due to rapid ground seeing variations and instrumental effects. The pointing direction is stable within 10 arcseconds on a daily timescale and drifts by only 34 arcseconds in 50 days. A truly continuous photometry of bright stars is possible in June (the noon sky background peaks at a magnitude R=15 arcsec-2 on June 22), but becomes challenging in July (the noon sky background magnitude is R=12.5 arcsec?2 on July 20). The weather conditions are estimated from the number of stars detected in the field. For the 2008...

Crouzet, Nicolas; Agabi, Karim; Rivet, Jean-Pierre; Bondoux, Erick; Challita, Zalpha; Fanteï-Caujolle, Yan; Fressin, François; Mékarnia, Djamel; Schmider, François-Xavier; Valbousquet, Franck; Blazit, Alain; Bonhomme, Serge; Abe, Lyu; Daban, Jean-Baptiste; Gouvret, Carole; Fruth, Thomas; Rauer, Heike; Erikson, Anders; Barbieri, Mauro; Aigrain, Suzanne; Pont, Frédéric

2009-01-01

73

Transit Observations of Venus's Atmosphere in 2012 from Terrestrial and Space Telescopes as Exoplanet Analogs  

Science.gov (United States)

We extensively observed the 8 June 2012 transit of Venus from several sites on Earth; we provide this interim status report about this and about two subsequent ToVs observed from space. From Haleakala Obs., we observed the entire June transit over almost 7 h with a coronagraph of the Venus Twilight Experiment B filter) and with a RED Epic camera to compare with simultaneous data from ESA's Venus Express, to study the Cytherean mesosphere; from Kitt Peak, we have near-IR spectropolarimetry at 1.6 µm from the aureole and during the disk crossing that compare well with carbon dioxide spectral models; from Sac Peak/IBIS we have high-resolution imaging of the Cytherean aureole for 22 min, starting even before 1st contact; from Big Bear, we have high-resolution imaging of Venus's atmosphere and the black-drop effect through 2nd contact; and we had 8 other coronagraphs around the world. For the Sept 21 ToV as seen from Jupiter, we had 14 orbits of HST to use Jupiter's clouds as a reflecting surface to search for an 0.01% diminution in light and a differential drop that would result from Venus's atmosphere by observing in both IR/UV, for which we have 170 HST exposures. As of this writing, preliminary data reduction indicates that variations in Jovian clouds and the two periods of Jupiter's rotation will be too great to allow extraction of the transit signal. For the December 20 ToV as seen from Saturn, we had 22 hours of observing time with VIMS on Cassini, for which we are looking for a signal of the 10-hr transit in total solar irradiance and of Venus's atmosphere in IR as an exoplanet-transit analog. Our Maui & Sac Peak expedition was sponsored by National Geographic Society's Committee for Research and Exploration; HST data reduction by NASA: HST-GO-13067. Some of the funds for the carbon dioxide filter for Sac Peak provided by NASA through AAS's Small Research Grant Program. We thank Rob Ratkowski of Haleakala Amateur Astronomers; Rob Lucas, Aram Friedman, Eric Pilger, Stan Truitt, and Steve Bisque/Software Bisque for Haleakala support/operations; Vasyl Yurchyshyn and Joseph Gangestad '06 of The Aerospace Corp. at Big Bear Solar Obs; LMSAL and Hinode science/operations team.

Pasachoff, Jay M.; Schneider, G.; Babcock, B. A.; Lu, M.; Penn, M. J.; Jaeggli, S. A.; Galayda, E.; Reardon, K. P.; Widemann, T.; Tanga, P.; Ehrenreich, D.; Vidal-Madjar, A.; Nicholson, P. D.; Dantowitz, R.

2013-06-01

74

Directed follow-up strategy of low-cadence photometric surveys in Search of Transiting Exoplanets - II. application to Gaia  

CERN Multimedia

In a previous paper we presented the Directed Follow-Up (DFU) approach, which we suggested can be used to efficiently augment low-cadence photometric surveys in a way that will optimize the chances to detect transiting exoplanets. In this paper we present preliminary tests of applying the DFU approach to the future ESA space mission Gaia. We demonstrate the strategy application to Gaia photometry through a few simulated cases of known transiting planets, using Gaia expected performance and current design. We show that despite the low cadence observations DFU, when tailored for Gaia's scanning law, can facilitate detection of transiting planets with ground-based observations, even during the lifetime of the mission. We conclude that Gaia photometry, although not optimized for transit detection, should not be ignored in the search of transiting planets. With a suitable ground-based follow-up network it can make an important contribution to this search.

Dzigan, Yifat

2012-01-01

75

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

76

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

77

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

78

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

79

The Relation Between Radius, Mass, and Incident Flux of Exoplanets  

Science.gov (United States)

We measure the mass of a modestly irradiated giant or "warm Jupiter," KOI-94d, in order to calculate its density. We wish to determine whether this planet, which is in a 22 day orbit and receives 107 times as much incident flux as the Earth, is bloated like "hot Jupiters" or as dense as our own Jupiter. In addition to its warm Jupiter, KOI-94 hosts at least 3 smaller planets, all of which were detected through transits by the Kepler Mission. This presents the opportunity to characterize a multi-planet system and to test dynamic stability and formation theory through observations of the masses and orbital elements of these planets. With 26 radial velocity measurements of KOI-94 from the W. M. Keck Observatory/HIRES, we measure the mass of the giant planet and upper limits to the masses of the three smaller planets. Transit timing variations will allow us to hone the mass measurements of the three smaller planets. Using the KOI-94 system and all other planets with published values for both mass and radius, we establish two fundamental planes for exoplanets that relate their mass, incident flux, and radius from a few Earth masses up to ten Jupiter masses: log(Rp/RE) = 0.007 + 0.53 log(M/ME) - 0.001 log(F/[erg/s/cm^2]) for Mp 150ME. We also solve these planes in density-mass-flux space: log(?p/[g/cm^3]) = 0.69 - 0.57 log(M/ME) + 0.02 log(F/[erg/s/cm^2]) for Mp 150ME.

Weiss, Lauren M.; Marcy, G. W.; Rowe, J.; Isaacson, H. T.; Howard, A.; Fortney, J. J.; Miller, N.; Demory, B.; Fischer, D.; Adams, E. A.; Dupree, A. K.; Howell, S. B.; Horch, E.; Everett, M. E.; Seager, S.; Fabrycky, D. C.

2013-01-01

80

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

 
 
 
 
81

Application of Transit Timing Variations to the Detection of Exoplanets and the Determination of their Orbital and Structural Properties  

Science.gov (United States)

We expand upon the results of Veras at el. (2010) and investigate the practical utility of exo-planet transit timing variations (TTVs) in a number of different scenarios: (i) We introduce significant non-coplanarity into our TTV investigations. This is because an increasing number of (Rossiter-McLaughlin) observations of transiting planets suggest that at least 10% of transiting planets are in retrograde orbits. We demonstrate that planets in retrograde orbits can frequently have significantly reduced TTVs, allowing the possibility that relatively massive, closely spaced systems of planets could escape detection via the TTV method (ii) We apply the TTV method to the expected flood of Kepler detections, and ask whether the planets that are directly detected first by Kepler (hot-Jupiters and hot-Neptunes ) can be employed to indirectly detect Earth-mass planets in the habitable zone via the TTVs they induce in the inner planet. We show that this is indeed the case for certain systems, illustrating the dependencies on mass, inclination, eccentricity, etc , but place particular emphasis on the importance of long data streams (iii) Finally, we turn to the specific example of the HAT-P-13 system, the first system in which a transiting planet is known to be accompanied by another planet in a well constrained orbit. We illustrate how observing TTVs in the inner planet can potentially constrain not only the eccentricity and the relative inclination of the (probably non-transiting) outer planet to the orbit of the inner planet , but potentially also the internal structure of the inner planet.

Payne, Matthew J.; Veras, D.; Ford, E. B.

2010-05-01

82

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

83

A ground-based Ks-band detection of the thermal emission from the transiting exoplanet WASP-4b  

CERN Multimedia

Secondary eclipses are a powerful tool to measure directly the thermal emission from extrasolar planets, and to constrain their type and physical parameters. We started a project to obtain reliable broad-band measurements of the thermal emission of transiting exoplanets. Ground-based high-cadence near-infrared relative photometry was used to obtain sub-millimagnitude precision light curve of a secondary eclipse of WASP-4b -- a 1.12 M_J hot Jupiter on a 1.34 day orbit around G7V star. The data show a clear ~10-\\sigma detection of the planet's thermal emission at 2.2 \\mu m. The calculated thermal emission corresponds to a fractional eclipse depth of 0.185^{+0.014}_{-0.013}%, with a related brightness temperature in Ks of T_B = 1995 \\pm 40 K, centered at T_C = 2455102.61162^{+0.00071}_{-0.00077} HJD. We could set a limit on the eccentricity of e cos \\omega=0.0027 \\pm 0.0018, compatible with a near-circular orbit. The calculated brightness temperature, as well as the specific models suggest a highly inefficient r...

Caceres, C; Minniti, D; Burrows, A; Selman, F; Melo, C; Naef, D; Mason, E; Pietrzynski, G

2011-01-01

84

Transiting exoplanets from the CoRoT space mission II. CoRoT-Exo-2b: A transiting planet around an active G star  

CERN Multimedia

Context. The CoRoT mission, a pioneer in exoplanet searches from space, has completed its first 150 days of continuous observations of ~12000 stars in the galactic plane. An analysis of the raw data identifies the most promising candidates and triggers the ground-based follow-up. Aims. We report on the discovery of the transiting planet CoRoT-Exo-2b, with a period of 1.743 days, and characterize its main parameters. Methods. We filter the CoRoT raw light curve of cosmic impacts, orbital residuals, and low frequency signals from the star. The folded light curve of 78 transits is fitted to a model to obtain the main parameters. Radial velocity data obtained with the SOPHIE, CORALIE and HARPS spectro-graphs are combined to characterize the system. The 2.5 min binned phase-folded light curve is affected by the effect of sucessive occultations of stellar active regions by the planet, and the dispersion in the out of transit part reaches a level of 1.09x10-4 in flux units. Results. We derive a radius for the planet...

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

2008-01-01

85

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report photometric and radial velocity observations of the XO-4 transiting planetary system, conducted with the FLWO 1.2 m telescope and the 8.2 m Subaru Telescope. Based on the new light curves, the refined transit ephemeris of XO-4b is $P$ $=$ 4.1250828$\\ \\pm\\ $0.0000040 d and $T_{\\rm c}$ [BJD$...

Narita, Norio; Hirano, Teruyuki; Sanchis Ojeda, Roberto; Winn, Joshua Nathan; Holman, Matthew J.; Sato, Bunei; Aoki, Wako

86

The NASA EPOXI mission of opportunity to gather ultraprecise photometry of known transiting exoplanets  

CERN Document Server

The NASA Discovery mission EPOXI, utilizing the Deep Impact flyby spacecraft, comprises two phases: EPOCh (Extrasolar Planet Observation and Characterization) and DIXI (Deep Impact eXtended Investigation). With EPOCh, we use the 30-cm high resolution visible imager to obtain ultraprecise photometric light curves of known transiting planet systems. We will analyze these data for evidence of additional planets, via transit timing variations or transits; for planetary moons or rings; for detection of secondary eclipses and the constraint of geometric planetary albedos; and for refinement of the system parameters. Over a period of four months, EPOCh observed four known transiting planet systems, with each system observed continuously for several weeks. Here we present an overview of EPOCh, including the spacecraft and science goals, and preliminary photometry results.

Christiansen, Jessie L; A'Hearn, Michael F; Deming, Drake; Holman, Matthew J; Ballard, Sarah; Weldrake, David T F; Barry, Richard K; Kuchner, Marc J; Livengood, Timothy A; Pedelty, Jeffrey; Schultz, Alfred; Hewagama, Tilak; Sunshine, Jessica M; Wellnitz, Dennis D; Hampton, Don L; Lisse, Carey M; Seager, Sara; Veverka, Joseph F

2008-01-01

87

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

CERN Multimedia

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

88

Exoplanet habitability.  

UK PubMed Central (United Kingdom)

The search for exoplanets includes the promise to eventually find and identify habitable worlds. The thousands of known exoplanets and planet candidates are extremely diverse in terms of their masses or sizes, orbits, and host star type. The diversity extends to new kinds of planets, which are very common yet have no solar system counterparts. Even with the requirement that a planet's surface temperature must be compatible with liquid water (because all life on Earth requires liquid water), a new emerging view is that planets very different from Earth may have the right conditions for life. The broadened possibilities will increase the future chances of discovering an inhabited world.

Seager S

2013-05-01

89

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

CERN Multimedia

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

90

Epoxi Exoplanet Transit Obs - Hriv Stellar Photometry V1.0  

Science.gov (United States)

This data set contains aperture photometry of known transiting planet systems GJ 436, HAT-P-4, HAT-P-7, TrES-2, TrES-3, and WASP-3 derived from radiance calibrated, clear #6 filtered images acquired by the Deep Impact High Resolution Visible CCD from 22 January through 31 August 2008 during the EPOCh phase of the EPOXI mission. The photometry data were derived from time series of continuous 50-second integrations used to observe each system for about three weeks, typically covering five or more transits as well as secondary eclipses.

Christiansen, J. L.; Ballard, S.; Deming, D.; Charbonneau, D.; Wellnitz, D. D.; McLaughlin, S. A.

2012-01-01

91

Prospects for Detection of Exoplanet Magnetic Fields Through Bow-Shock Observations During Transits  

CERN Multimedia

An asymmetry between the ingress and egress times was observed in the near-UV light curve of the transit planet WASP-12b. Such asymmetry led us to suggest that the early ingress in the UV light curve of WASP-12b, compared to the optical observations, is caused by a shock around the planet, and that shocks should be a common feature in transiting systems. Here, we classify all the transiting systems known to date according to their potential for producing shocks that could cause observable light curve asymmetries. We found that 36/92 of known transiting systems would lie above a reasonable detection threshold and that the most promising candidates to present shocks are: WASP-19b, WASP-4b, WASP-18b, CoRoT-7b, HAT-P-7b, CoRoT-1b, TrES-3, and WASP-5b. For prograde planets orbiting outside the co-rotation radius of fast rotating stars, the shock position, instead of being ahead of the planetary motion as in WASP-12b, trails the planet. In this case, we predict that the light curve of the planet should present a la...

Vidotto, A A; Helling, Ch

2010-01-01

92

Five New Transit Epochs of the Exoplanet OGLE-TR-111b  

CERN Multimedia

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 April and May 2008. 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 discard TTVs with amplitudes larger than 1.5 minutes over a 4-year observation time baseline, in agreement with the recent result by Adams et al.(2010a). Dynamical simulations fully exclude the presence of additional planets in the system with masses greater than 1.3, 0.4 and 0.5 M_earth at the 3:2, 1:2, 2:1 resonances, respectively. We also place an upper limit of about 30 M_earth on the mass of potential second planets in the region between the 3:2 and 1:2 mean-motion resonances.

Hoyer, Sergio; López-Morales, Mercedes; Díaz, Rodrigo; Chambers, John E; Minniti, Dante

2011-01-01

93

A Spitzer Search for Water in the Transiting Exoplanet HD189733b  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present Spitzer Space Telescope observations of the extrasolar planet HD189733b primary transit, obtained simultaneously at 3.6 and 5.8 microns with the Infrared Array Camera. The system parameters, including planetary radius, stellar radius, and impact parameter are derived from fits to the tran...

Ehrenreich, David; Hébrard, Guillaume; Lecavelier Des Etangs, Alain; K Sing, David; Désert, Jean-Michel; Bouchy, François

94

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

International Nuclear Information System (INIS)

[en] 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.

95

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...

Gandolfi, D.; Hébrard, G.; Alonso, R.; Deleuil, M.; Guenther, E. W.; Fridlund, M.; Endl, M.; Eigmüller, P.; Csizmadia, Szilard

96

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

97

Comparison of current models for Hot Jupiters to the sample of transiting exoplanets  

CERN Multimedia

A growing number (over 100!) of extra-solar planets (ESPs) have been discovered by transit photometry, and these systems are important because the transit strongly constrains their orbital inclination and allows accurate physical parameters for the planet to be derived, especially their radii. Their mass-radius relation allows us to probe their internal structure. In the present work we calculate Safronov numbers for the current sample of ESP and compare their masses and radii to current models with the goal of obtaining better constrains on their formation processe. Our calculation of Safronov numbers for the current TESP sample does show 2 classes, although about 20% lie above the formal Class I definition. These trends and recent results that argue against a useful distinction between Safronov classes are under further investigation. Mass-radius relations for the current sample of TESP are inconsistent with ESP models with very large core masses (\\geq 100 M\\oplus). Most TESP with radii near 1RJ are consist...

Lund, Michael

2010-01-01

98

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

99

Near-UV and optical observations of the transiting exoplanet TrES-3b  

CERN Document Server

We observed nine primary transits of the hot Jupiter TrES-3b in several optical and near-UV photometric bands from 2009 June to 2012 April in an attempt to detect its magnetic field. Vidotto, Jardine and Helling suggest that the magnetic field of TrES-3b can be constrained if its near-UV light curve shows an early ingress compared to its optical light curve, while its egress remains unaffected. Predicted magnetic field strengths of Jupiter-like planets should range between 8 G and 30 G. Using these magnetic field values and an assumed B_star of 100 G, the Vidotto et al. method predicts a timing difference of 5-11 min. We did not detect an early ingress in our three nights of near-UV observations, despite an average cadence of 68 s and an average photometric precision of 3.7 mmag. However, we determined an upper limit of TrES-3b's magnetic field strength to range between 0.013 and 1.3 G (for a 1-100 G magnetic field strength range for the host star, TrES-3) using a timing difference of 138 s derived from the N...

Turner, Jake D; Hardegree-Ullman, Kevin K; Carleton, Timothy M; Walker-LaFollette, Amanda M; Crawford, Benjamin E; Smith, Carter-Thaxton W; McGraw, Allison M; Small, Lindsay C; Rocchetto, Marco; Cunningham, Kathryn I; Towner, Allison P M; Zellem, Robert; Robertson, Amy N; Guvenen, Blythe C; Schwarz, Kamber R; Hardegree-Ullman, Emily E; Collura, Daniel; Henz, Triana N; Lejoly, Cassandra; Richardson, Logan L; Weinand, Michael A; Taylor, Joanna M; Daugherty, Michael J; Wilson, Ashley A; Austin, Carmen L

2012-01-01

100

The transiting exoplanet CoRoT-11b and its peculiar tidal evolution  

Directory of Open Access Journals (Sweden)

Full Text Available CoRoT-11b is a fairly massive hot-Jupiter (Mp = 2.33 ± 0.34 MJup ) in a 3 days orbit around a F6 V star with an age of 2 ± 1 Gyr. The relatively high projected rotational velocity of the star (v sin i? = 40 ± 5 km/s) places CoRoT-11 among the most rapidly rotating planet hosting stars discovered so far. Assuming that the star is seen equator-on, the v sin i? and the star radius (R? = 1.37±0.03 R?) translate into a stellar rotation period of 1.73±0.26 days. This peculiar planet/star con?guration o?ers an unique opportunity to study the tidal evolution of the system. Owing to the strong tidal interaction, the planet would have moved outwards, from a starting semi-major axis corresponding to an orbital period almost synchronized with the stellar rotation. We found that the present value of the tidal quality factor Q?s could be measured by a timing of the mid-epoch of the transits to be observed with an accuracy of about 0.5 ? 1 seconds over a time baseline of about 25 years.

Gandol? D.; Lanza A.F.; Damiani C.

2011-01-01

 
 
 
 
101

IMPROVED MODELING OF THE ROSSITER-McLAUGHLIN EFFECT FOR TRANSITING EXOPLANETS  

International Nuclear Information System (INIS)

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 simulations. Finally, as one application of the new formula, we reassess the impact of the differential rotation on the RM velocity anomaly. We show that differential rotation of a rapidly rotating star may have a significant impact on future RM observations.

2011-12-01

102

Constraining High Speed Winds in Exoplanet Atmospheres Through Observations of Anomalous Doppler Shifts During Transit  

CERN Multimedia

Three-dimensional (3-D) 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 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 blue shift of spectral lines in transmission on the order of the wind speed. Indeed, Snellen et al. (2010) recently observed a 2 +/- 1 km/s blue shift of CO transmission features for HD 209458b, which has been interpreted as a detection of the day-to-night winds that have been predicted by 3-D atmospheric dynamics modeling. Here we present the results of a coupled 3-D atmospheric dynamics and transmission spectrum model, which predicts the Doppler-shifted spectrum of a hot Jupiter during transit resulting from winds in the pl...

Kempton, Eliza Miller-Ricci

2011-01-01

103

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

104

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

105

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

106

Water in exoplanets.  

UK PubMed Central (United Kingdom)

Exoplanets--planets orbiting around stars other than our own Sun--appear to be common. Significant research effort is now focused on the observation and characterization of exoplanet atmospheres. Species such as water vapour, methane, carbon monoxide and carbon dioxide have been observed in a handful of hot, giant, gaseous planets, but cooler, smaller planets such as Gliese 1214b are now analysable with current telescopes. Water is the key chemical dictating habitability. The current observations of water in exoplanets from both space and the ground are reviewed. Controversies surrounding the interpretation of these observations are discussed. Detailed consideration of available radiative transfer models and linelists are used to analyse these differences in interpretation. Models suggest that there is a clear need for data on the pressure broadening of water transitions by H(2) at high temperatures. The reported detections of water appear to be robust, although final confirmation will have to await the better quality observational data provided by currently planned dedicated space missions.

Tinetti G; Tennyson J; Griffith CA; Waldmann I

2012-06-01

107

The Transit Light Curve project. XIV. Confirmation of Anomalous Radii for the Exoplanets TrES-4b, HAT-P-3b, and WASP-12b  

CERN Document Server

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 +/- 0.056 R_Jup and 1.736 +/- 0.092 R_Jup, 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 +/- 0.055 R_Jup, 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.

Chan, Tucker; Winn, Joshua N; Holman, Matthew J; Sanchis-Ojeda, Roberto; Esquerdo, Gil; Everett, Mark

2011-01-01

108

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.

2011-01-01

109

Ground-based Characterization of Exoplanet Atmospheres  

Science.gov (United States)

Of the many confirmed exoplanets, we know the detailed chemical composition and temperature structure of only a handful. Transiting exoplanets present us with the interesting opportunity to characterize their atmospheres. Until 2009, only space-based platforms had been successful at this type of characterization. Since then, ground-based spectroscopy has made significant contributions to exoplanet characterization. The IRTF/SpeX instrument combination has been used to reliably reproduce space-based results while obtaining new and unexpected information. Our team has been applying lessons learned at IRTF/SpeX to the design of a new ground-based spectrometer, the New Mexico Tech Exoplanet Spectroscopic Survey Instrument (NESSI). NESSI, a collaborative effort between researchers at NMT, MRO, and NASA JPL, is purpose built to characterize exoplanet atmospheres. In anticipation of first light in a few months, I will present an update on NESSI progress, including a summary of NESSI's unique features.

Bloemhard, H.

2012-10-01

110

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

111

The NASA Exoplanet Archive: Data and Tools for Exoplanet Research  

Science.gov (United States)

We describe the contents and functionality of the NASA Exoplanet Archive, a database and toolset 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.; Chen, X.; 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.; Ramírez, 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.

2013-08-01

112

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

113

Lucky Imaging Survey for Binary Exoplanet Hosts  

Science.gov (United States)

Binary or multiple stars are common in our neighbourhood, and many of the exoplanets we know of belong to a star in such a system. The influence of a second star on planet formation can be probed by comparing properties of planets in binary/multiple-star systems with those of single-star planets. We present some of the results from our Lucky Imaging survey for binary companions to hosts of transiting exoplanets.

Bergfors, Carolina; Brandner, Wolfgang; Daemgen, Sebastian; Henning, Thomas

2012-04-01

114

The Transit Light Curve Project. X. A Christmas Transit of HD 17156b  

CERN Multimedia

Photometry is presented of the Dec. 25, 2007 transit of HD 17156b, which has the longest orbital period and highest orbital eccentricity of all the known transiting exoplanets. New measurements of the stellar radial velocity are also presented. All the data are combined and integrated with stellar-evolutionary modeling to derive refined system parameters. The planet's mass and radius are found to be 3.212_{-0.082}^{+0.069} Jupiter masses and 1.023_{-0.055}^{+0.070} Jupiter radii. The corresponding stellar properties are 1.263_{-0.047}^{+0.035} solar masses and 1.446_{-0.067}^{+0.099} solar radii. The planet is smaller by 1 sigma than a theoretical solar-composition gas giant with the same mass and equilibrium temperature, a possible indication of heavy-element enrichment. The midtransit time is measured to within 1 min, and shows no deviation from a linear ephemeris (and therefore no evidence for orbital perturbations from other planets). We provide ephemerides for future transits and superior conjunctions. T...

Winn, Joshua N; Henry, Gregory W; Torres, Guillermo; Fischer, Debra; Johnson, John Asher; Marcy, Geoffrey W; Shporer, Avi; Mazeh, Tsevi

2008-01-01

115

Pulsation Frequencies and Modes of Giant Exoplanets  

CERN Document Server

We calculate the eigenfrequencies and eigenfunctions of the acoustic oscillations of giant exoplanets and explore the dependence of the characteristic frequency and the eigenfrequencies on several parameters: the planet mass, the planet radius, the core mass, and the heavy element mass fraction in the envelope. We provide the eigenvalues for degree l up to 8 and radial order n up to 12. For the selected values of l and n, we find that the pulsation eigenfrequencies depend strongly on the planet mass and radius, especially at high frequency. We quantify this dependence through the calculation of the characteristic frequency which gives us an estimate of the scale of the eigenvalue spectrum at high frequency. For the mass range ~0.5 \\leq M_P \\leq 15 M_J, and fixing the planet radius to the Jovian value, we find that the characteristic frequency is ~164.0 (M_P/M_J)^{0.48} microHz, where M_P is the planet mass and M_J is Jupiter's mass. For the radius range from 0.9 to 2.0 R_J, and fixing the planet's mass to the...

Bihan, Bastien Le

2012-01-01

116

Eclipsing Binary Science Via the Merging of Transit and Doppler Exoplanet Survey Data - A Case Study With the MARVELS Pilot Project and SuperWASP  

CERN Multimedia

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 M_1 = 0.92 +/- 0.1 M_solar, we find M_2 = 0.610 +/- 0.036 M_solar, R_1 = 0.932 +/- 0.076 R_solar and R_2 = 0.559 +/- 0.102 R_solar, and find that both stars have masses and radii consistent with model pr...

Fleming, Scott W; Hebb, Leslie; Stassun, Keivan G; Ge, Jian; Cargile, Phillip A; Ghezzi, Luan; De Lee, Nathan M; Wisniewski, John; Gary, Bruce; de Mello, Gustavo F Porto; Ferreira, Leticia; Zhao, Bo; Anderson, David R; Wan, Xiaoke; Hellier, Coel; Guo, Pengcheng; West, Richard G; Mahadevan, Suvrath; Pollacco, Don; Lee, Brian; Cameron, Andrew Collier; van Eyken, Julian C; Skillen, Ian; Crepp, Justin R; Nguyen, Duy Cuong; Kane, Stephen R; Paegert, Martin; da Costa, Luiz Nicolaci; Maia, Marcio A G; Santiago, Basilio X

2011-01-01

117

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

International Nuclear Information System (INIS)

[en] Several exoplanets have recently been imaged at wide separations of >10 AU from their parent stars. These span a limited range of ages ( 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+350-60 Myr, GJ 504b has an estimated mass of 4+4.5-1.0 Jupiter masses, among the lowest of directly imaged planets. Its projected separation of 43.5 AU exceeds the typical outer boundary of ?30 AU predicted for the core accretion mechanism. GJ 504b is also significantly cooler (510+30-20 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

2013-09-01

118

A TRANSIT TIMING ANALYSIS OF NINE RISE LIGHT CURVES OF THE EXOPLANET SYSTEM TrES-3  

International Nuclear Information System (INIS)

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 /R * = 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 ?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 constant period either have relatively little out-of-transit coverage or have clear systematics. A new ephemeris was calculated using the transit times and was found to be Tc (0) = 2454632.62610 ± 0.00006 HJD and P = 1.3061864 ± 0.0000005 days. The transit times were then used to place upper mass limits as a function of the period ratio of a potential perturbing planet, showing that our data are sufficiently sensitive to have probed sub-Earth mass planets in both interior and exterior 2:1 resonances, assuming that the additional planet is in an initially circular orbit.

2009-08-01

119

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.

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.

2013-01-01

120

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

CERN Multimedia

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 precedence, and revise the system parameters accordingly. The planetary radius is about 1 sigma larger than the theoretical radius for a hydrogen-helium planet of the given mass and insolation. To help in planning future observations, we provide refined transit and occultation ephemerides.

Winn, Joshua N; 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

 
 
 
 
121

EXOPLANET CHARACTERIZATION BY PROXY: A TRANSITING 2.15 R{sub Circled-Plus} PLANET NEAR THE HABITABLE ZONE OF THE LATE K DWARF KEPLER-61  

Energy Technology Data Exchange (ETDEWEB)

We present the validation and characterization of Kepler-61b: a 2.15 R{sub Circled-Plus} 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{sub Circled-Plus} 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.

Ballard, Sarah; Charbonneau, David; Fressin, Francois; Torres, Guillermo; Irwin, Jonathan; Newton, Elisabeth [University of Washington, Seattle, WA 98195 (United States); Desert, Jean-Michel; Crepp, Justin R.; Shporer, Avi [California Institute of Technology, Pasadena, CA 91125 (United States); Mann, Andrew W. [Institute for Astronomy, University of Hawai' i, Honolulu, HI 96822 (United States); Ciardi, David R. [NASA Exoplanet Science Institute/Caltech, Pasadena, CA 91125 (United States); Henze, Christopher E.; Bryson, Stephen T.; Howell, Steven B. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Horch, Elliott P. [Southern Connecticut State University, New Haven, CT 06515 (United States); Everett, Mark E., E-mail: sarahba@uw.edu [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States)

2013-08-20

122

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

123

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

CERN Multimedia

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

124

Transit spectrophotometry of the exoplanet HD189733b. I. Searching for water but finding haze with HST NICMOS  

CERN Multimedia

We present Hubble Space Telescope near-infrared transit photometry of the nearby hot-Jupiter HD189733b. The observations were taken with the NICMOS instrument during five transits, with three transits executed with a narrowband filter at 1.87 microns and two performed with a narrowband filter at 1.66 microns. Our observing strategy using narrowband filters is insensitive to the usual HST intra-orbit and orbit-to-orbit measurement of systematic errors, allowing us to accurately and robustly measure the near-IR wavelength dependance of the planetary radius. Our measurements fail to reproduce the Swain et al. absorption signature of atmospheric water below 2 microns at a 5-sigma confidence level. We measure a planet-to-star radius contrast of 0.15498+/-0.00035 at 1.66 microns and a contrast of 0.15517+/-0.00019 at 1.87 microns. Both of our near-IR planetary radii values are in excellent agreement with the levels expected from Rayleigh scattering by sub-micron haze particles, observed at optical wavelengths, indi...

Sing, David K; Etangs, A Lecavelier des; Ballester, G E; Vidal-Madjar, A; Parmentier, V; Hébrard, G; Henry, G W

2009-01-01

125

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

126

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 betwee...

Bouchy, F.; Queloz, D.; Deleuil, M.; Loeillet, B.; Hatzes, A. P.; Aigrain, S.; Alonso, R.; Auvergne, M.; Baglin, A.; Barge, P.

127

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

128

ANALYTIC DESCRIPTION OF THE ROSSITER-MCLAUGHLIN EFFECT FOR TRANSITING EXOPLANETS: CROSS-CORRELATION METHOD AND COMPARISON WITH SIMULATED DATA  

International Nuclear Information System (INIS)

We obtain analytical expressions for the velocity anomaly due to the Rossiter-McLaughlin (RM) 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., which is based on the first moment of distorted stellar lines. Our new formula contains a term dependent on the stellar line width, which becomes important when rotational line broadening is appreciable. We generate mock transit spectra for four existing exoplanetary systems (HD 17156, TrES-2, TrES-4, and HD 209458) following the procedure of Winn et al., 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 RM effect, and explains the previously observed dependence of the velocity anomaly on the stellar rotation velocity.

2010-01-20

129

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

Science.gov (United States)

We present the detection and characterization of the two new transiting, close-in, giant extrasolar planets KOI-200 b and KOI-889 b. They were first identified by the Kepler team as promising candidates from photometry of the Kepler satellite; we then 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-200 b has mass and radius of 0.68 ± 0.09 MJup and 1.32 ± 0.14 RJup; it orbits in 7.34 days a F8V host star with mass and radius of 1.40-0.11+0.14 M? and 1.51 ± 0.14 R?. The planet KOI-889 b is a massive planet with mass and radius of 9.9 ± 0.5 MJup and 1.03 ± 0.06 RJup; 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? and 0.88 ± 0.04 R?. Both planets lie on eccentric orbits and are located just at the frontier between regimes where tides can explain circularization and where tidal effects are negligible. The two planets are among the first detected and characterized thanks to observations secured with HARPS-N, the new spectrograph recently mounted at the Telescopio Nazionale Galileo. These results illustrate the benefits that could be obtained from joint studies using two spectrographs as SOPHIE and HARPS-N.

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

2013-06-01

130

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

CERN Multimedia

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

131

The history of exoplanet detection.  

UK PubMed Central (United Kingdom)

I summarize the early developments of the more quantitative aspects of exoplanet detection. After a brief overview of the observational methods currently applied to exoplanet searches and a summary of the first true exoplanet detections resulting from these various techniques, the more relevant historical background is organized according to the observational techniques that are currently most relevant.

Perryman M

2012-10-01

132

The distribution of exoplanet masses  

CERN Document Server

The present study derives the distribution of secondary masses M2 for the 67 exoplanets and very low-mass brown dwarf companions of solar-type stars, known as of April 4, 2001. This distribution is related to the distribution of M2 sin i through an integral equation of Abel's type. Although a formal solution exists for this equation, it is known to be ill-behaved, and thus very sensitive to the statistical noise present in the input M2 sin i distribution. To overcome that difficulty, we present two robust, independent approaches: (i) the formal solution of the integral equation is numerically computed after performing an optimal smoothing of the input distribution, (ii) the Lucy-Richardson algorithm is used to invert the integral equation. Both approaches give consistent results. The resulting statistical distribution of exoplanet true masses reveals that there is no reason to ascribe the transition between giant planets and brown dwarfs to the threshold mass for deuterium ignition (about 13 MJ). The M2 distr...

Jorissen, A; Udry, S

2001-01-01

133

Transiting exoplanets from the CoRoT space mission. XV. CoRoT-15b: a brown dwarf transiting companion  

CERN Multimedia

We report the discovery by the CoRoT space mission of a transiting brown dwarf orbiting a F7V star with an orbital period of 3.06 days. CoRoT-15b has a radius of 1.12 +0.30 -0.15 Rjup, a mass of 63.3 +- 4.1 Mjup, and is thus the second transiting companion lying in the theoretical mass domain of brown dwarfs. CoRoT-15b is either very young or inflated compared to standard evolution models, a situation similar to that of M-dwarfs stars orbiting close to solar-type stars. Spectroscopic constraints and an analysis of the lightcurve favors a spin period between 2.9 and 3.1 days for the central star, compatible with a double-synchronisation of the system.

Bouchy, F; Guillot, T; Aigrain, S; Carone, L; Cochran, W D

2010-01-01

134

Atmospheric Circulation of Exoplanets  

CERN Multimedia

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

135

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

136

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 ...

Csizmadia, Szilard; Moutou, C.; Deleuil, M.; Cabrera, J.; Fridlund, M.; Gandolfi, D.; Aigrain, S.; Alonso, R.; Almenara, J*-M

137

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

138

The Optical Design of CHARIS: An Exoplanet IFS for the Subaru Telescope  

CERN Document Server

High-contrast imaging techniques now make possible both imaging and spectroscopy of planets around nearby stars. We present the optical design for the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS), a lenslet-based, cryogenic integral field spectrograph (IFS) for imaging exoplanets on the Subaru telescope. The IFS will provide spectral information for 138x138 spatial elements over a 2.07 arcsec x 2.07 arcsec field of view (FOV). CHARIS will operate in the near infrared (lambda = 1.15 - 2.5 microns) and will feature two spectral resolution modes of R = 18 (low-res mode) and R = 73 (high-res mode). Taking advantage of the Subaru telescope adaptive optics systems and coronagraphs (AO188 and SCExAO), CHARIS will provide sufficient contrast to obtain spectra of young self-luminous Jupiter-mass exoplanets. CHARIS will undergo CDR in October 2013 and is projected to have first light by the end of 2015. We report here on the current optical design of CHARIS and its unique innovations.

Peters-Limbach, Mary Anne; Kasdin, N Jeremy; Driscoll, Dave; Galvin, Michael; Foster, Allen; Carr, Michael A; LeClerc, Dave; Fagan, Rad; McElwain, Michael W; Knapp, Gillian; Brandt, Timothy; Janson, Markus; Guyon, Olivier; Jovanovic, Nemanja; Martinache, Frantz; Hayashi, Masahiko; Takato, Naruhisa

2013-01-01

139

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

140

Using SPICA Space Telescope to characterize Exoplanets  

CERN Multimedia

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

 
 
 
 
141

TEST - The Tautenburg Exoplanet Search Telescope  

CERN Document Server

The Tautenburg Exoplanet Search Telescope (TEST) is a robotic telescope system. The telescope uses a folded Schmidt Camera with a 300mm main mirror. The focal length is 940mm and it gives a 2.2 square degree field of view. Dome, mount, and CCD cameras are controlled by a software bundle made by Software Bisque. The automation of the telescope includes selection of the night observing program from a given framework, taking darks and skyflats, field identification, guiding, data taking, and archiving. For the search for transiting exoplanets and variable stars an automated psf photometry based on IRAF and a lightcurve analysis based on ESO-Midas are conducted. The images and the results are managed using a PostgreSQL database.

Eigmüller, Philipp

2008-01-01

142

Mass-radius relationships of rocky exoplanets  

CERN Multimedia

Mass and radius of planets transiting their host stars are provided by radial velocity and photometric observations. Structural models of solid exoplanet interiors are then constructed by using equations of state for the radial density distribution, which are compliant with the thermodynamics of the high-pressure limit. However, to some extent those structural models suffer from inherent degeneracy or non-uniqueness problems owing to a principal lack of knowledge of the internal differentiation state and/or the possible presence of an optically thick atmosphere. We here discuss the role of corresponding measurement errors, which adversely affect determinations of a planet's mean density and bulk chemical composition. Precise measurements of planet radii will become increasingly important as key observational constraints for radial density models of individual solid low-mass exoplanets or super-Earths.

Sohl, F; Rauer, H

2012-01-01

143

Dynamical Constraints on Exoplanets  

CERN Multimedia

Dynamical studies of new exoplanet systems are a critical component of the discovery and characterisation process. Such studies can provide firmer constraints on the parameters of the newly discovered planets, and may even reveal that the proposed planets do not stand up to dynamical scrutiny. Here, we demonstrate how dynamical studies can assist the characterisation of such systems through two examples: QS Virginis and HD 73526.

Horner, Jonti; Tinney, Chris; Hinse, Tobias C; Marshall, Jonathan P

2013-01-01

144

New exoplanets from the SuperWASP-North survey  

Directory of Open Access Journals (Sweden)

Full Text Available We present the current status of the WASP search for transiting exoplanets, focusing on recent planet discoveries from SuperWASP-North and the joint equatorial region (-20?Dec?+20) observed by both WASP telescopes. We report the results of monitoring of WASP planets, and discuss how these contribute to our understanding of planet properties and their diversity.

Faedi F.; Barros S. C. C.; Pollacco D.; Simpson E. K.; McCormac J.; Moulds V.; Watson C.; Todd I.; Keenan F.; Fitzsimmons A.

2011-01-01

145

Photometric stability analysis of the Exoplanet Characterisation Observatory  

CERN Multimedia

Photometric stability is a key requirement for time-resolved spectroscopic observations of transiting extrasolar planets. In the context of the Exoplanet Characterisation Observatory (EChO) mission design, we here present and investigate means of translating spacecraft pointing instabilities as well as temperature fluctuation of its optical chain into an overall error budget of the exoplanetary spectrum to be retrieved. Given the instrument specifications as of date, we investigate the magnitudes of these photometric instabilities in the context of simulated observations of the exoplanet HD189733b secondary eclipse.

Waldmann, I P; Swinyard, B; Tinetti, G; Amaral-Rogers, A; Spencer, L; Tessenyi, M; Ollivier, M; Foresto, V Coudé du

2013-01-01

146

Exoplanets search and characterization with the SOPHIE spectrograph at OHP  

Directory of Open Access Journals (Sweden)

Full Text Available Several programs of exoplanets search and characterization have been started with SOPHIE at the 1.93-m telescope of Haute-Provence Observatory, France. SOPHIE is an environmentally stabilized echelle spectrograph dedicated to high-precision radial velocity measurements. The objectives of these programs include systematic searches for exoplanets around di?erent types of stars, characterizations of planet-host stars, studies of transiting planets through RossiterMcLaughlin e?ect, follow-up observations of photometric surveys. The instrument SOPHIE and a review of its latest results are presented here.

Hébrard G.

2011-01-01

147

The NStED Stellar and Exoplanet Hosting Star Service  

CERN Multimedia

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

148

Detectability of Exoplanet Periastron Passage in the Infra-Red  

CERN Multimedia

Characterization of exoplanets has matured in recent years, particularly through studies of exoplanetary atmospheres of transiting planets at infra-red wavelenegths. The primary source for such observations has been the Spitzer Space Telescope but these studies are anticipated to continue with the James Webb Space Telescope (JWST). A relatively unexplored region of exoplanet parameter space is the thermal detection of long-period eccentric planets during periastron passage. Here we describe the thermal properties and albedos of long-period giant planets along with the eccentricities of those orbits which allow them to remain within the habitable zone. We further apply these results to the known exoplanets by calculating temperatures and flux ratios for the IRAC passbands occupied by warm Spitzer, considering both low and high thermal redistribution efficiencies from the perspective of an observer. We conclude with recommendations on which targets are best suited for follow-up observations.

Kane, Stephen R

2011-01-01

149

DETECTABILITY OF EXOPLANET PERIASTRON PASSAGE IN THE INFRARED  

International Nuclear Information System (INIS)

Characterization of exoplanets has matured in recent years, particularly through studies of exoplanetary atmospheres of transiting planets at infrared wavelengths. The primary source for such observations has been the Spitzer Space Telescope but these studies are anticipated to continue with the James Webb Space Telescope. A relatively unexplored region of exoplanet parameter space is the thermal detection of long-period eccentric planets during periastron passage. Here we describe the thermal properties and albedos of long-period giant planets along with the eccentricities of those orbits which allow them to remain within the habitable zone. We further apply these results to the known exoplanets by calculating temperatures and flux ratios for the IRAC passbands occupied by warm Spitzer, considering both low and high thermal redistribution efficiencies from the perspective of an observer. We conclude with recommendations on which targets are best suited for follow-up observations.

2011-11-01

150

The spin-orbit angles of the transiting exoplanets WASP-1b, WASP-24b, WASP-38b and HAT-P-8b from Rossiter-McLaughlin observations  

CERN Multimedia

We present observations of the Rossiter-McLaughlin effect for the transiting exoplanet systems WASP-1, WASP-24, WASP-38 and HAT-P-8, and deduce the orientations of the planetary orbits with respect to the host stars' rotation axes. The planets WASP-24b, WASP-38b and HAT-P-8b appear to move in prograde orbits and be well aligned, having sky-projected spin orbit angles consistent with zero: {\\lambda} = -4.7 $\\pm$ 4.0{\\deg}, {\\lambda} = -5 + 27{\\deg}/-38{\\deg} and {\\lambda} = 2.2 +12.1{\\deg}/-9.6{\\deg}, respectively. The host stars have Teff < 6250 K and conform with the trend of cooler stars having low obliquities. WASP-38b is a massive planet on a moderately long period, eccentric orbit so may be expected to have a misaligned orbit given the high obliquities measured in similar systems. However, we find no evidence for a large spin-orbit angle. By contrast, WASP-1b joins the growing number of misaligned systems and has an almost polar orbit, {\\lambda} = -79 +4.5{\\deg}/-4.3{\\deg}. It is neither very massive,...

Simpson, E K; Cameron, A Collier; Hebrard, G; Anderson, D R; Barros, S C C; Boisse, I; Bouchy, F; Faedi, F; Gillon, M; Hebb, L; Keenan, F P; Miller, G R M; Moutou, C; Queloz, D; Skillen, I; Sorensen, P; Stempels, H C; Triaud, A; Watson, C A; Wilson, P A; Belfast, Queen's University; Andrews, University of St; de Paris, Institut d'Astrophysique; de Haute-Provence, Observatoire; University, Keele; de Liege, Universite; University, Vanderbilt; de Marseille, Laboratoire d'Astrophysique; de Geneve, Observatoire; Telescope, Nordic Optical; University, Uppsala; Exeter, University of

2010-01-01

151

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

152

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

153

Observing exoplanets from Brazil: the first try  

Science.gov (United States)

This project consists in mapping a 4-square-degree region searching for exoplanets using the transit method. This “mini-survey” will be the first use of the 16? robotic telescope developed by Universidade Federal de Santa Catarina (UFSC-Brazil) and Laboratório Nacional de Astrofísica (LNA/MCT-Brazil). The chosen region is over the Columba constellation and our first observations have shown that we have enough signal-to-noise ratio to search for transits on about 20,000 stars with ~13 < I < 16 mag, a magnitude range between the OGLE and HAT projects. In this star sample we expect to find about a dozen planets with transits duration of 1-3 hours and magnitude depth from 0.001 to 0.010 mag. As for other projects, all information will became public as a VO service.

Saito, Roberto; Silva, Paulo Henrique; Kanaan, Antonio; Schoenell, William; Fraga, Luciano; Bruch, Albert

2009-02-01

154

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 M? = 1.21 ± 0.05 ?M? and radius R? = 1.65 ?±? 0.04?R?. The planet has a mass of MP = 1.11 ± 0.06?MJup and radius of RP = 1.29 ?± 0.03?RJup. The resulting bulk density is only ? = 0.71 ?± 0.06?g?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 ?30% larger radius.

Guenther, E. W.; Díaz, R. F.

2012-01-01

155

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...

Rauer, H.; Queloz, D.; Csizmadia, Szilard; Deleuil, M.; Alonso, R.; Aigrain, S.; Almenara, J. M.; Auvergne, M.; Baglin, A.

156

Coreless Terrestrial Exoplanets  

CERN Multimedia

Differentiation in terrestrial planets is expected to include the formation of a metallic iron core. We predict the existence of terrestrial planets that have differentiated but have no metallic core--planets that are effectively a giant silicate mantle. We discuss two paths to forming a coreless terrestrial planet, whereby the oxidation state during planetary accretion and solidification will determine the size or existence of any metallic core. Under this hypothesis, any metallic iron in the bulk accreting material is oxidized by water, binding the iron in the form of iron oxide into the silicate minerals of the planetary mantle. The existence of such silicate planets has consequences for interpreting the compositions and interior density structures of exoplanets based on their mass and radius measurements.

Elkins-Tanton, L

2008-01-01

157

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.

2013-01-01

158

Carbon cycles on super-Earth exoplanets  

Science.gov (United States)

On Earth, the long-term global carbon cycle primarily consists of a balance between volcanic emissions of CO2 and the formation and burial of carbonate rocks (the carbonate-silicate weathering 'thermostat'), with important modifications due to the biosphere. On gas giant planets, the carbon cycle is driven by photolysis in the upper atmosphere: methane is converted to longer-chain hydrocarbons such as acetylene, ethane and soot particles, which are then dissociated by thermolysis lower in the atmosphere where the temperature and pressure are much higher. Hydrogen escape rates on terrestrial exoplanets are predicted to be a strong function of their orbital distances, ages and masses. In particular, larger exoplanets around stars with lower extreme ultraviolet (XUV) emissions may have significant difficulties in losing their hydrogen to space, and hence may retain H2 envelopes of varying mass. It is therefore interesting to investigate what happens in the transition between the terrestrial and hydrogen-dominated regimes. Here we present a first attempt to investigate the range of scenarios that occur for terrestrial mass (~1-10 ME) planets with varying hydrogen escape rates. We are developing climate evolution simulations for a range of cases that account for surface processes (primarily outgassing and weathering), hydrogen escape to space, and simple atmospheric chemistry. We discuss various feedbacks that may occur as a result of the influences of CO2, CH4 and H2 on atmospheric and surface temperatures. Finally, we discuss the implications of our results for future observations, with a particular emphasis on the search for biosignatures on exoplanets similar to the Earth.

Wordsworth, Robin; Pierrehumbert, Raymond; Hébrard, Eric

2013-04-01

159

Trawling for transits in a sea of noise: A Search for Exoplanets by Analysis of WASP Optical Lightcurves and Follow-up (SEAWOLF)  

CERN Document Server

Studies of transiting Neptune-size planets orbiting close to nearby bright stars can inform theories of planet formation because mass and radius and therefore mean density can be accurately estimated and compared with interior models. The distribution of such planets with stellar mass and orbital period relative to their Jovian-mass counterparts can test scenarios of orbital migration, and whether "hot" (period < 10d) Neptunes evolved from "hot" Jupiters as a result of mass loss. We searched 1763 late K and early M dwarf stars for transiting Neptunes by analyzing photometry from the Wide Angle Search for Planets and obtaining high-precision ($<10^{-3}$) follow-up photometry of stars with candidate transit signals. One star in our sample (GJ 436) hosts a previously reported hot Neptune. We identified 92 candidate signals among 80 other stars and carried out 148 observations of predicted candidate transits with 1-2 m telescopes. Data on 70 WASP signals rules out transits for 39 of them; 28 other signals a...

Gaidos, E; Lepine, S; Colon, K D; Maravelias, G; Narita, N; Chang, E; Beyer, J; Fukui, A; Armstrong, J D; Zezas, A; Fulton, B J; Mann, A W; West, R G; Faedi, F

2013-01-01

160

PRECISE ESTIMATES OF THE PHYSICAL PARAMETERS FOR THE EXOPLANET SYSTEM HD 17156 ENABLED BY HUBBLE SPACE TELESCOPE FINE GUIDANCE SENSOR TRANSIT AND ASTEROSEISMIC OBSERVATIONS  

International Nuclear Information System (INIS)

We present observations of three distinct transits of HD 17156b obtained with the Fine Guidance Sensors on board the Hubble Space Telescope. We analyzed both the transit photometry and previously published radial velocities to find the planet-star radius ratio Rp /R* = 0.07454 ± 0.00035, inclination i = 86.49+0.24-0.20 deg, and scaled semimajor axis a/R* = 23.19+0.32-0.27. This last value translates directly to a mean stellar density determination ?* = 0.522+0.021-0.018 g cm-3. Analysis of asteroseismology observations by the companion paper of Gilliland et al. provides a consistent but significantly refined measurement of ?* = 0.5308 ± 0.0040. We compare stellar isochrones to this density estimate and find M* = 1.275 ± 0.018 Msun and a stellar age of 3.37+0.20-0.47 Gyr. Using this estimate of M* and incorporating the density constraint from asteroseismology, we model both the photometry and published radial velocities to estimate the planet radius Rp = 1.0870 ± 0.0066 RJ and the stellar radius R* = 1.5007 ± 0.0076 Rsun. The planet radius is larger than that found in previous studies and consistent with theoretical models of a solar-composition gas giant of the same mass and equilibrium temperature. For the three transits, we determine the times of mid-transit to a precision of 6.2 s, 7.6 s, and 6.9 s, and the transit times for HD 17156 do not show any significant departures from a constant period. The joint analysis of transit photometry and asteroseismology presages similar studies that will be enabled by the NASA Kepler Mission.

2011-01-01

 
 
 
 
161

Precise Estimates of the Physical Parameters for the Exoplanet System HD 17156 Enabled by Hubble Space Telescope Fine Guidance Sensor Transit and Asteroseismic Observations  

DEFF Research Database (Denmark)

We present observations of three distinct transits of HD 17156b obtained with the Fine Guidance Sensors on board the Hubble Space Telescope. We analyzed both the transit photometry and previously published radial velocities to find the planet-star radius ratio Rp /R sstarf = 0.07454 ± 0.00035, inclination i = 86.49+0.24 –0.20 deg, and scaled semimajor axis a/R sstarf = 23.19+0.32 –0.27. This last value translates directly to a mean stellar density determination ?sstarf = 0.522+0.021 –0.018 g cm–3. Analysis of asteroseismology observations by the companion paper of Gilliland et al. provides a consistent but significantly refined measurement of ?sstarf = 0.5308 ± 0.0040. We compare stellar isochrones to this density estimate and find M sstarf = 1.275 ± 0.018 M sun and a stellar age of 3.37+0.20 –0.47 Gyr. Using this estimate of M sstarf and incorporating the density constraint from asteroseismology, we model both the photometry and published radial velocities to estimate the planet radius Rp = 1.0870 ± 0.0066 RJ and the stellar radius R sstarf = 1.5007 ± 0.0076 R sun. The planet radius is larger than that found in previous studies and consistent with theoretical models of a solar-composition gas giant of the same mass and equilibrium temperature. For the three transits, we determine the times of mid-transit to a precision of 6.2 s, 7.6 s, and 6.9 s, and the transit times for HD 17156 do not show any significant departures from a constant period. The joint analysis of transit photometry and asteroseismology presages similar studies that will be enabled by the NASA Kepler Mission.

Nutzman, Philip; Gilliland, Ronald L.

2011-01-01

162

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

CERN Multimedia

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

163

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 obse...

Hébrard, G.; Evans, T. M.; Alonso, R.; Fridlund, M.; Ofir, A.; Aigrain, S.; Guillot, T.; Almenara, J. M.; Auvergne, M.

164

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 searc...

Rouan, D.; Parviainen, H.; Moutou, C.; Deleuil, M.; Fridlund, M.; Ofir, A.; Havel, M.; Aigrain, S.; Alonso, R.; Auvergne, M.

165

Observational Evidence for Tidal Destruction of Exoplanets  

CERN Multimedia

The distribution of the orbits of close-in exoplanets shows evidence for on-going removal and destruction by tides. Tides raised on a planet's host star cause the planet's orbit to decay, even after the orbital eccentricity has dropped to zero. Comparison of the observed orbital distribution and predictions of tidal theory show good qualitative agreement, suggesting tidal destruction of close-in exoplanets is common. The process can explain the observed cut-off in small a-values, the clustering of orbital periods near three days, and the relative youth of transiting planets. Contrary to previous considerations, a mechanism to stop the inward migration of close-in planets at their current orbits is not necessarily required. Planets nearing tidal destruction may be found with extremely small a, possibly already stripped of any gaseous envelope. The recently discovered CoRoT-Exo-7 b may be an example of such a planet and will probably be destroyed by tides within the next few Gyrs. Also, where one or more planet...

Jackson, Brian; Greenberg, Richard

2009-01-01

166

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

CERN Multimedia

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 "alarm-mode" 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. The phase folded lightcurve is used to fit the transit signal and derive the main planetary parameters. Radial velocity follow-up observations were initiated to secure the detection and to derive the planet mass. Results. We report the detection of CoRoT-5b, detected during observations of the LRa01 field, the first long-duration field in the galactic anticenter direction. CoRoT-5b is a "hot Jupiter-type" planet with a radius of 1.388(+0.046, -0.047) R_Jup, a mass of 0.467(+0.047, -0.024) M_Jup, and therefore, a mean density of 0.21...

Rauer, H; Csizmadia, Sz; Deleuil, M; Alonso, R; Aigrain, S; Almenara, J M; Auvergne, M; Baglin, A; Barge, P; Borde, P; Bouchy, F; Bruntt, H; Cabrera, J; Carone, L; Carpano, S; De la Reza, R; Deeg, H J; Dvorak, R; Erikson, A; Fridlund, M; Gandolfi, D; Gillon, M; Guillot, T; Günther, E; Hatzes, A; Hébrard, G; Kabath, P; Jorda, L; Lammer, H; Léger, A; Llebaria, A; Magain, P; Mazeh, T; Moutou, C; Ollivier, M; Paetzold, M; Pont, F; Rabus, M; Renner, S; Rouan, D; Shporer, A; Samuel, B; Schneider, J; Triaud, A H M J; Wuchterl, G

2009-01-01

167

Stellar companions to exoplanet host stars with Astralux  

Science.gov (United States)

A close stellar companion influences the formation of planets in the system. The occurrence of stellar companions and characteristics of the stars and planets in the system provide constraints on the formation processes. We present results from our high-resolution Lucky Imaging survey for binary exoplanet host stars, including the discovery of stellar companion candidates to the transiting planet hosts WASP-12 and HAT-P-8.

Bergfors, Carolina; Brandner, Wolfgang; Henning, Thomas; Daemgen, Sebastian

2011-11-01

168

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

CERN Document Server

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

169

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

CERN Multimedia

We report the discovery of very shallow (DF/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 due to the presence of 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 use CoRoT color 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 are derived from optical spectra, which were then combined with the CoRoT light curve to derive parameters of the companion. We examine carefully all conceivable cases of false positives, and all tests performed support the planetary hypothesis. Blends with separation larger than 0.40 arcsec or triple systems are almost excluded with a 8 10-4 ris...

Léger, A; Schneider, J; Barge, P; Fridlund, M; Samuel, B; Ollivier, M; Günther, E; Deleuil, M; Deeg, H J; Auvergne, M; Alonso, R; Aigrain, S; Alapini, A; Almenara, J M; Baglin, A; Barbieri, M; Bruntt, H; Borde, 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; Paetzold, M; Pont, F; Queloz, D; Rauer, H; Renner, S; Samadi, R; Shporer, A; Sotin, Ch; Tingley, B; Wuchterl, G

2009-01-01

170

The thermal emission of the exoplanets WASP-1b and WASP-2b  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present a comparative study of the thermal emission of the transiting exoplanets WASP-1b and WASP-2b using the Spitzer Space Telescope. The two planets have very similar masses but suffer different levels of irradiation and are predicted to fall either side of a sharp transition between planets w...

Wheatley, Peter J; Collier Cameron, Andrew; Harrington, Joseph; Fortney, Jonathan J; Simpson, James M; Anderson, David R

171

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

172

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.

Crouzet N.; Guillot T.; Agabi K.; Daban J.-B.; Abe L.; Mekarnia D.; Rivet J.-P.; Fanteï-Caujolle Y.; Fressin F.; Gouvret C.; Schmider F.-X.; Valbousquet F.; Blazit A.; Rauer H.; Erikson A.; Fruth T.; Aigrain S.; Pont F.; Barbieri M.

2011-01-01

173

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

174

Evidence for a lost population of close-in exoplanets  

CERN Multimedia

We investigate the evaporation history of known transiting exoplanets in order to consider the origin of observed correlations between mass, surface gravity and orbital period. We show that the survival of the known planets at their current separations is consistent with a simple model of evaporation, but that many of the same planets would not have survived closer to their host stars. These putative closer-in systems represent a lost population that could account for the observed correlations. We conclude that the relation underlying the correlations noted by Mazeh et al. (2005) and Southworth et al. (2007) is most likely a linear cut-off in the M^2/R^3 vs a^-2 plane, and we show that the distribution of exoplanets in this plane is in close agreement with the evaporation model.

Davis, Timothy A

2009-01-01

175

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

CERN Multimedia

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

176

Transiting exoplanets from the CoRoT space mission IV: CoRoT-Exo-4b: A transiting planet in a 9.2 day synchronous orbit  

CERN Multimedia

CoRoT, the first space-based transit search, provides ultra-high precision light curves with continuous time-sampling over periods, of up to 5 months. This allows the detection of transiting planets with relatively long periods, and the simultaneous study of the host star's photometric variability. In this letter, we report on the discovery of the transiting giant planet CoRoT-Exo-4b and use the CoRoT light curve to perform a detailed analysis of the transit and to determine the stellar rotation period. The CoRoT light curve was pre-processed to remove outliers and correct for orbital residuals and artefacts due to hot pixels on the detector. After removing stellar variability around each transit, the transit light curve was analysed to determine the transit parameters. A discrete auto-correlation function method was used to derive the rotation period of the star from the out-of-transit light curve. We derive periods for the planet's orbit and star's rotation of 9.20205 +/- 0.00037 and 8.87 +/- 1.12 days resp...

Aigrain, S; Ollivier, M; Pont, F; Jorda, L; Almenara, J M; Alonso, R; Barge, P; Borde, P; Bouchy, F; Deeg, H; De la Reza, R; Deleuil, M; Dvorak, R; Erikson, A; Fridlund, M; Gondoin, P; Gillon, M; Guillot, T; Hatzes, A; Lammer, H; Lanza, A F; Léger, A; Llebaria, A; Magain, P; Mazeh, T; Moutou, C; Paetzold, M; Pinte, C; Queloz, D; Rauer, H; Rouan, D; Schneider, J; Wuchter, G; Zucker, S

2008-01-01

177

LkCa 15: A Young Exoplanet Caught at Formation?  

CERN Multimedia

Young and directly imaged exoplanets offer critical tests of planet-formation models that are not matched by RV surveys of mature stars. These targets have been extremely elusive to date, with no exoplanets younger than 10--20 Myr and only a handful of direct-imaged exoplanets at all ages. We report the direct imaging discovery of a likely (proto)planet around the young (~2 Myr) solar analog LkCa 15, located inside a known gap in the protoplanetary disk (a "transitional disk"). Our observations use non-redundant aperture masking interferometry at 3 epochs to reveal a faint and relatively blue point source ($M_K'=9.1+/-0.2, K'-L'=0.98+/-0.22), flanked by approximately co-orbital emission that is red and resolved into at least two sources (M_L'=7.5+/-0.2, K'-L'=2.7+/-0.3; M_L'=7.4+/-0.2, K'-L'=1.94+/-0.16). We propose that the most likely geometry consists of a newly-formed (proto)planet that is surrounded by dusty material. The nominal estimated mass is ~6 M_{Jup} according to the 1 Myr hot-start models. Howev...

Kraus, Adam L

2011-01-01

178

A Search for Additional Planets in the Nasa Epoxi Observations of the Exoplanet System Gj 436  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present time series photometry of the M dwarf transiting exoplanet system GJ 436 obtained with the Extrasolar Planet Observation and Characterization (EPOCh) component of the NASA EPOXI mission. We conduct a search of the high-precision time series for additional planets around GJ 436, which coul...

Seager, Sara; Ballard, Sarah; Christiansen, Jessie L.; Charbonneau, David; Deming, Drake; Holman, Matthew J.; Fabrycky, Daniel

179

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 determin...

Fridlund, M.; Hebrard, G.; Alonso, R.; Deleuil, M.; Gandolfi, D.; Gillon, Michaël; Bruntt, H.; Alapini, A.; Csizmadia, Szilard

180

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...

Cabrera, J.; Bruntt, H.; Ollivier, M.; Díaz, R. F.; Csizmadia, Szilard; Aigrain, S.; Alonso, R.; Almenara, J*-M; Auvergne, M.

 
 
 
 
181

Signals of exomoons in averaged light curves of exoplanets  

CERN Multimedia

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

182

The Exoplanet Eccentricity Distribution from Kepler Planet Candidates  

CERN Document Server

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

183

High-precision ground-based photometry of exoplanets  

Directory of Open Access Journals (Sweden)

Full Text Available High-precision photometry of transiting exoplanet systems has contributed significantly to our understanding of the properties of their atmospheres. The best targets are the bright exoplanet systems, for which the high number of photons allow very high signal-to-noise ratios. Most of the current instruments are not optimised for these high-precision measurements, either they have a large read-out overhead to reduce the readnoise and/or their field-of-view is limited, preventing simultaneous observations of both the target and a reference star. Recently we have proposed a new wide-field imager for the Observatoir de Mont-Megantic optimised for these bright systems (PI: Jayawardhana). The instruments has a dual beam design and a field-of-view of 17' by 17'. The cameras have a read-out time of 2 seconds, significantly reducing read-out overheads. Over the past years we have obtained significant experience with how to reach the high precision required for the characterisation of exoplanet atmospheres. Based on our experience we provide the following advice: Get the best calibrations possible. In the case of bad weather, characterise the instrument (e.g. non-linearity, dome flats, bias level), this is vital for better understanding of the science data. Observe the target for as long as possible, the out-of-transit baseline is as important as the transit/eclipse itself. A short baseline can lead to improperly corrected systematic and mis-estimation of the red-noise. Keep everything (e.g. position on detector, exposure time) as stable as possible. Take care that the defocus is not too strong. For a large defocus, the contribution of the total flux from the sky-background in the aperture could well exceed that of the target, resulting in very strict requirements on the precision at which the background is measured.

de Mooij Ernst J.W.; Jayawardhana Ray

2013-01-01

184

The NASA Exoplanet Science Institute Archives: KOA and NStED  

Science.gov (United States)

The NASA Exoplanet Science Institute (NExScI) maintains a series of archival services in support of NASA’s planet finding and characterization goals. Two of the larger archival services at NExScI are the Keck Observatory Archive (KOA) and the NASA Star and Exoplanet Database (NStED). KOA, a collaboration between the W. M. Keck Observatory and NExScI, serves raw data from the High Resolution Echelle Spectrograph (HIRES) and extracted spectral browse products. As of June 2009, KOA hosts over 28 million files (4.7 TB) from over 2,000 nights. In Spring 2010, it will begin to serve data from the Near-Infrared Echelle Spectrograph (NIRSPEC). NStED is a general purpose archive with the aim of providing support for NASA’s planet finding and characterization goals, and stellar astrophysics. There are two principal components of NStED: a database of (currently) all known exoplanets, and images; and an archive dedicated to high precision photometric surveys for transiting exoplanets. NStED is the US portal to the CNES mission CoRoT, the first space mission dedicated to the discovery and characterization of exoplanets. These archives share a common software and hardware architecture with the NASA/IPAC Infrared Science Archive (IRSA). The software architecture consists of standalone utilities that perform generic query and retrieval functions. They are called through program interfaces and plugged together to form applications through a simple executive library.

Berriman, G. B.; Ciardi, D.; Abajian, M.; Barlow, T.; Bryden, G.; von Braun, K.; Good, J.; Kane, S.; Kong, M.; Laity, A.; Lynn, M.; Elroy, D. M.; Plavchan, P.; Ramirez, S.; Schmitz, M.; Stauffer, J.; Wyatt, P.; Zhang, A.; Goodrich, R.; Mader, J.; Tran, H.; Tsubota, M.; Beekley, A.; Berukoff, S.; Chan, B.; Lau, C.; Regelson, M.; Saucedo, M.; Swain, M.

2010-12-01

185

Results of the First Exoplanet Transmission Spectroscopy Attempt with GTC  

Science.gov (United States)

In June 2011 we attempted to measure the first atmospheric transmission spectrum of an exoplanet with the GTC. We observed the hot Jupiter TrEs-2b during two transit epochs using the long-slit spectroscopic mode of OSIRIS. The technique consists of doing differential spectrophotometry by placing the planet host and a nearby star on a wide slit during a planetary transit. We then monitor both objects for the duration of the event to obtain simultaneous transit coverage at wavelengths between ~5000 and 9000 Å. We present here the results of our first attempt with this new technique, which holds the potential of providing a 5-10 fold improvement on the efficiency of exoplanet primary and secondary eclipse observations with the GTC. Finally, we also present a summary of the science done so far with observations from the ESO/GTC program 182.C.2018. Fernandez, J. M., et al. 2009, ApJ, 137, 4911 Sing, D. K., et al. 2011, A&A, 527, 73

López-Morales, M.; Ribas, I.; Sing, D. K.; Huitson, C.; Rodler, F.; García-Melendo, E.; Belu, A.; Cabrera-Lavers, A.

2013-05-01

186

The Origin of the Exoplanets  

CERN Document Server

We explore two ways in which objects of planetary masses can form. One is in disk systems like the solar system. The other is in dense clusters where stars and brown dwarfs form. We do not yet have the instrumental accuracy to detect multiplanet systems with masses like those in solar system; with our present technology from a distant site, only the effects of Jupiter could be detected. We show that the orbital characteristics (eccentricities and semimajor axes) of stellar, brown dwarf, and exoplanet companions of solar-type stars are all the same within our measuring accuracies and are very different than the planets in the solar system. The period ratios in multiplanet systems do not distinguish between the two models. We conclude that most of the exoplanets found to date are formed like stellar companions and not in disk systems like the solar system. This conclusion explains why metal-poor stars lack planets: because metal-poor stars lack stellar companions with short periods. The distribution of exoplane...

Abt, Helmut A

2010-01-01

187

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  

CERN Multimedia

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) with an estimated age of 3.0 Gyr. The planet mass is close to 3 times that of Jupiter. The star has a metallicity of 0.2 dex lower than the Sun, and a relatively high $^7$Li abundance. While thelightcurveindicatesamuchhigherlevelof activity than, e.g., the Sun, there is no sign of activity spectroscopically in e.g., the [Ca ] H&K lines.

Fridlund, M; Alonso, R; Deleuil, M; Gandolfi, D; Gillon, M; Bruntt, H; Alapini, A; Csizmadia, Sz; Guillot, T; Lammer, H; Aigrain, S; Almenara, J M; Auvergne, M; Baglin, A; Barge, P; Borde, P; Bouchy, F; Cabrera, J; Carone, L; Carpano, S; Deeg, H J; De la Reza, R; Dvorak, R; Erikson, A; Ferraz-Mello, S; Guenther, E; Gondoin, P; Hartog, R den; Hatzes, A; Jorda, L; Leger, A; Llebaria, A; Magain, P; Mazeh, T; Moutou, C; Ollivier, M; Patzold, M; Queloz, D; Rauer, H; Rouan, D; Samuel, B; Schneider, J; Shporer, A; Stecklum, B; Tingley, B; Weingrill, J; Wuchterl, G

2010-01-01

188

Optical Phase Curves of Kepler Exoplanets  

Science.gov (United States)

We conducted a comprehensive search for optical phase variations of all close-in (a/R sstarf 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 (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

2013-07-01

189

The McDonald Observatory Exoplanet Program  

Science.gov (United States)

We present a review of the McDonald Observatory Exoplanet Program at the Harlan J. Smith 2.7 m Telescope and the Hobby-Eberly Telescope. Besides planet confirmation and validation for NASA's Kepler mission we also carry out a precise Doppler survey of 400 solar-type stars and 100 M dwarfs. We will summarize current results, present several new exoplanet discoveries and discuss future prospects in observing strategies and instrumentation.

Endl, Michael; Cochran, W. D.; MacQueen, P. J.; Robertson, P.; Brugamyer, E. J.; Caldwell, C.

2012-01-01

190

Mapping Directly Imaged Giant Exoplanets  

CERN Multimedia

With the increasing number of directly imaged giant exoplanets the current atmosphere models are often not capable of fully explaining the spectra and luminosity of the sources. A particularly challenging component of the atmosphere models is the formation and properties of condensate cloud layers, which fundamentally impact the energetics, opacity, and evolution of the planets. Here we present a suite of techniques that can be used to estimate the level of rotational modulations these planets may show. We propose that the time--resolved observations of such periodic photometric and spectroscopic variations of extrasolar planets due to their rotation can be used as a powerful tool to probe the heterogeneity of their optical surfaces. We address and discuss the following questions: a) what planet properties can be deduced from the light curve and/or spectra, and in particular can we determine rotation periods, spot--coverage, spot colors, spot spectra; b) what is the optimal configuration of instrument/wavelen...

Kostov, Veselin B

2012-01-01

191

Venus Twilight Experiment : Observation and analysis of the aureole during the 2012 transit  

Science.gov (United States)

On 5-6 June 2012, Venus will be transiting the Sun for the last time in this century. This unique opportunity, besides offering the opportunity of investigating the mesosphere of the planet, also provides a significant nearby analog of exoplanet transits. Several studies using the transmission spectroscopy technique have provided significant insights into the atmospheric composition, structure, and dynamics of hot giant exoplanets. In this context, Venus is our closest model for a telluric exoplanet.

Widemann, T.; Tanga, P.; Sicardy, B.; Machado, P.; Braga-Ribas, F.; Veillet, C.; Pasachoff, J.; Colas, F.; Vachier, F.; Bouley, S.; Maquet, L.; Berthier, J.; Fukuhara, T.; Luz, D.

2012-09-01

192

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

CERN Multimedia

Short-period exoplanets potentially lose envelope masses during their evolution because of atmospheric escape caused by the intense 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 exploring 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, Hiroyuki

2013-01-01

193

Exoplanets: New Approaches to their Discovery and Characterization  

Science.gov (United States)

I review several novel approaches to exoplanet detection and characterization, including transit-timing variations (TTV), exoplanet mapping using phase variations and eclipses, and chromospheric transits. TTV may be used to characterize multi-planet systems by measuring deviations from periodicity of a transiting planet due to the gravitational pull of companion planets. As of September 2010, one example of a system with TTV has been found by the Kepler satellite, probably the first of many. In principle TTV may be used to discover companion planets, which has failed to date with ground-based telescopes, but will likely occur with Kepler. Infrared phase variations measured with Spitzer have been used to characterize the climate of hot Jupiters and to make longitudinal maps, constraining atmospheric circulation models. I will present the first eclipse map of a hot Jupiter based on Spitzer, which may be a taste of what will be done with JWST. Chromospheric transits of optically-thin emission lines should show a dip at each limb. These will have low signal-to-noise, but might be used to discover giant planets orbiting sub-giant stars. Finally, I will look well into the future towards studying planets in their habitable zones. Observations of Earth with the EPOXI satellite show that phase variations may be used to make longitudinal maps of habitable planets with continents and oceans, even in the presence of variable cloud cover. Such observations might be carried with future large space-based occulting or coronagraphic telescopes. I will conclude with some more speculative ideas on the future of planet detection and characterization.

Agol, Eric

2011-01-01

194

A Temperature and Abundance Retrieval Method for Exoplanet Atmospheres  

CERN Document Server

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

195

The Ultraviolet Radiation Environment Around M dwarf Exoplanet Host Stars  

CERN Document Server

The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. 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 FUV and NUV wavelengths. The combined FUV+NUV spectra are publically 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 ~37-75% of the tota...

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

2012-01-01

196

Studying the atmosphere of the exoplanet HAT-P-7b via secondary eclipse measurements with EPOXI, Spitzer and Kepler  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The highly irradiated transiting exoplanet, HAT-P-7b, currently provides one of the best opportunities for studying planetary emission in the optical and infrared wavelengths. We observe six near-consecutive secondary eclipses of HAT-P-7b at optical wavelengths with the EPOXI spacecraft. We place an...

Seager, Sara; Madhusudhan, Nikku; Christiansen, Jessie L.; Ballard, Sarah; Charbonneau, David; Matthew J., Holman

197

Planetesimal Compositions in Exoplanet Systems  

CERN Document Server

We have used recent surveys of the composition of exoplanet host stars to investigate the expected composition of condensed material in planetesimals formed beyond the snow line in the circumstellar nebulae of these systems. Of the major solid forming elements, we find that, as for the Sun, the C and O abundances (and particularly the C/O abundance ratio) have the most significant effect on the composition of icy planetesimals formed in these systems. The calculations use a self-consistent model for the condensation sequence of volatile ices from the nebula gas after refractory (silicate and metal) phases have condensed. The resultant proportions of refractory phases and ices were calculated for a range of nebular temperature structure and redox conditions. Planetesimals in systems with sub-solar C/O should be water ice-rich, with lower than solar mass fractions of refractory materials, while in super-solar C/O systems planetesimals should have significantly higher fractions of refractories, in some cases hav...

Johnson, Torrence V; Lunine, Jonathan I; Madhusudhan, Nikku

2012-01-01

198

ATMOSPHERIC CHEMISTRY OF VENUS-LIKE EXOPLANETS  

International Nuclear Information System (INIS)

We use thermodynamic calculations to model atmospheric chemistry on terrestrial exoplanets that are hot enough for chemical equilibria between the atmosphere and lithosphere, as on Venus. The results of our calculations place constraints on abundances of spectroscopically observable gases, the surface temperature and pressure, and the mineralogy of the planetary surface. These results will be useful in planning future observations of the atmospheres of terrestrial-sized exoplanets by current and proposed space observatories such as the Hubble Space Telescope, Spitzer, the James Webb Space Telescope, and Darwin.

2011-03-01

199

Dynamical Measurements of the Interior Structure of Exoplanets  

CERN Multimedia

Giant gaseous planets often reside on orbits in sufficient proximity to their host stars for the planetary quadrupole gravitational field to become non-negligible. In presence of an additional planetary companion, a precise characterization of the system's orbital state can yield meaningful constraints on the transiting planet's interior structure. However, such methods can require a very specific type of system. This paper explores the dynamic range of applicability of these methods and shows that interior structure calculations are possible for a wide array of orbital architectures. The HAT-P-13 system is used as a case study, and the implications of perturbations arising from a third distant companion on the feasibility of an interior calculation are discussed. We find that the method discussed here is likely to be useful in studying other planetary systems, allowing the possibility of an expanded survey of the interiors of exoplanets.

Becker, Juliette C

2013-01-01

200

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

 
 
 
 
201

A FRAMEWORK FOR QUANTIFYING THE DEGENERACIES OF EXOPLANET INTERIOR COMPOSITIONS  

International Nuclear Information System (INIS)

Several transiting super-Earths are expected to be discovered in the coming few years. While tools to model the interior structure of transiting planets exist, inferences about the composition are fraught with ambiguities. We present a framework to quantify how much we can robustly infer about super-Earth and Neptune-size exoplanet interiors from radius and mass measurements. We introduce quaternary diagrams to illustrate the range of possible interior compositions for planets with four layers (iron core, silicate mantles, water layers, and H/He envelopes). We apply our model to CoRoT-7b, GJ 436b, and HAT-P-11b. Interpretation of planets with H/He envelopes is limited by the model uncertainty in the interior temperature, while for CoRoT-7b observational uncertainties dominate. We further find that our planet interior model sharpens the observational constraints on CoRoT-7b's mass and radius, assuming the planet does not contain significant amounts of water or gas. We show that the strength of the limits that can be placed on a super-Earth's composition depends on the planet's density; for similar observational uncertainties, high-density super-Mercuries allow the tightest composition constraints. Finally, we describe how techniques from Bayesian statistics can be used to take into account in a formal way the combined contributions of both theoretical and observational uncertainties to ambiguities in a planet's interior composition. On the whole, with only a mass and radius measurement an exact interior composition cannot be inferred for an exoplanet because the problem is highly underconstrained. Detailed quantitative ranges of plausible compositions, however, can be found.

2010-04-01

202

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

CERN Multimedia

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

203

What can exoplanets tell us about our Solar System?  

CERN Multimedia

We update our analysis of recent exoplanet data that gives us a partial answer to the question: How does our Solar System compare to the other planetary systems in the Universe? Exoplanets detected between January and August 2002 strengthen the conclusion that Jupiter is a typical massive planet rather than an outlier. The trends in detected exoplanets do not rule out the hypothesis that our Solar System is typical. They support it.

Lineweaver, C H; Hidas, M; Lineweaver, Charles H.; Grether, Daniel; Hidas, Marton

2002-01-01

204

A TEMPERATURE AND ABUNDANCE RETRIEVAL METHOD FOR EXOPLANET ATMOSPHERES  

International Nuclear Information System (INIS)

We present a new method to retrieve molecular abundances and temperature profiles from exoplanet atmosphere photometry and spectroscopy. We run millions of one-dimensional (1D) atmosphere models in order to cover the large range of allowed parameter space. 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. The major difference from traditional 1D radiative transfer models is the parametric P-T profile, which essentially means adopting energy balance only at the top of the atmosphere and not in each layer. We see the parametric P-T model as a parallel approach to the traditional exoplanet atmosphere models that rely on several free parameters to encompass unknown absorbers and energy redistribution. The parametric P-T profile captures the basic physical features of temperature structures in planetary atmospheres (including temperature inversions), and fits a wide range of published P-T profiles, including those of solar system planets. We apply our temperature and abundance retrieval method to the atmospheres of two transiting exoplanets, HD 189733b and HD 209458b, which have the best Spitzer and Hubble Space Telescope data available. 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 dayside thermal inversion in an average 1D temperature profile. We also report independent detections of H2O, CO, CH4, and CO2 on the dayside of HD 209458b, based on six-channel Spitzer photometry. We report constraints for HD 189733b due to individual data sets separately; a few key observations are variable in different data sets at similar wavelengths. Moreover, a noticeably strong CO2 absorption in one data set is significantly weaker in another. We must, therefore, acknowledge the strong possibility that the atmosphere is variable, both in its energy redistribution state and in the chemical abundances.

2009-12-10

205

A Temperature and Abundance Retrieval Method for Exoplanet Atmospheres  

Science.gov (United States)

We present a new method to retrieve molecular abundances and temperature profiles from exoplanet atmosphere photometry and spectroscopy. We run millions of one-dimensional (1D) atmosphere models in order to cover the large range of allowed parameter space. 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. The major difference from traditional 1D radiative transfer models is the parametric P-T profile, which essentially means adopting energy balance only at the top of the atmosphere and not in each layer. We see the parametric P-T model as a parallel approach to the traditional exoplanet atmosphere models that rely on several free parameters to encompass unknown absorbers and energy redistribution. The parametric P-T profile captures the basic physical features of temperature structures in planetary atmospheres (including temperature inversions), and fits a wide range of published P-T profiles, including those of solar system planets. We apply our temperature and abundance retrieval method to the atmospheres of two transiting exoplanets, HD 189733b and HD 209458b, which have the best Spitzer and Hubble Space Telescope data available. 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 dayside thermal inversion in an average 1D temperature profile. We also report independent detections of H2O, CO, CH4, and CO2 on the dayside of HD 209458b, based on six-channel Spitzer photometry. We report constraints for HD 189733b due to individual data sets separately; a few key observations are variable in different data sets at similar wavelengths. Moreover, a noticeably strong CO2 absorption in one data set is significantly weaker in another. We must, therefore, acknowledge the strong possibility that the atmosphere is variable, both in its energy redistribution state and in the chemical abundances.

Madhusudhan, N.; Seager, S.

2009-12-01

206

ELODIE metallicity-biased search for transiting Hot Jupiters II. A very hot Jupiter transiting the bright K star HD189733  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Among the 160 known exoplanets, mainly detected in large radial-velocity surveys, only 8 have a characterization of their actual mass and radius thanks to the two complementary methods of detection: radial velocities and photometric transit. We started in March 2004 an exoplanet-search programme bia...

Bouchy, Francois; Udry, Stephane; Mayor, Michel; Moutou, Claire; Pont, Frederic; Iribarne, Nicolas; Da Silva, Ronaldo

207

TERRESTRIAL, HABITABLE-ZONE EXOPLANET FREQUENCY FROM KEPLER  

Energy Technology Data Exchange (ETDEWEB)

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 (HZ) exoplanets. The Kepler census is assumed to be complete for bright stars (magnitude <14.0) having transiting planets >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 9%, ice giants 18%, and gas giants 3%; the population has a planet frequency with respect to period which follows a power-law relation dN/dP {approx} P{sup {beta}-1}, with {beta} {approx_equal} 0.71 {+-} 0.08; and an extrapolation to longer periods gives the frequency of terrestrial planets in the HZs of FGK stars as {eta}{sub Circled-Plus} {approx_equal} (34 {+-} 14)%. Thus about one-third of FGK stars are predicted to have at least one terrestrial, HZ planet.

Traub, Wesley A., E-mail: wtraub@jpl.nasa.gov [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2012-01-20

208

A lower mass for the exoplanet WASP-21b  

CERN Multimedia

We present high precision transit observations of the exoplanet WASP-21b, obtained with the RISE instrument mounted on 2.0m Liverpool Telescope. A transit model is fitted, coupled with an MCMC routine to derive accurate system parameters. The two new high precision transits allow to estimate the stellar density directly from the light curve. Our analysis suggests that WASP-21 is evolving off the main sequence which led to a previous overestimation of the stellar density. Using isochrone interpolation, we find a stellar mass of 0.86 \\pm 0.04 Msun which is significantly lower than previously reported (1.01 \\pm 0.03 Msun). Consequently, we find a lower planetary mass of $0.27 \\pm 0.01 Mjup$. A lower inclination (87.4 \\pm 0.3 degrees) is also found for the system than previously reported, resulting in a slightly larger stellar (R_* =1.10 \\pm 0.03 Rsun) and planetary radius (R_p = 1.14 \\pm 0.04 Rjup). The planet radius suggests a hydrogen/helium composition with no core which strengthens the correlation between pl...

Barros, S C C; Gibson, N P; Howarth, I D; Keenan, F P; Simpson, E K; Skillen, I; Steele, I A; .,

2011-01-01

209

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  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Madhusudhan, Nikku; Seager, Sara; Christiansen, Jessie L.; Ballard, Sarah; Charbonneau, David; Deming, Drake; Holman, Matthew J.

210

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

211

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

212

Asteroseismology of exoplanets-host stars  

CERN Document Server

Studying the internal structure of exoplanets-host stars compared to that of similar stars without detected planets is particularly important for the understanding of planetary formation. The observed overmetallicity of stars around which planets have been detected may be a hint in that respect. In this framework, asteroseismic studies represent an excellent tool to determine the structural differences between stars with and without detected planets. After a general discussion on this subject, I present the special cases of three different stars: $\\mu$ Arae which has been observed with the HARPS spectrograph in June 2004, $\\iota$ Horologii, that we have studied in detail and will be observed with HARPS in November 2006, and finally HD 52265, one of the main targets of the COROT mission, an exoplanets-host star which will be observed with the COROT satellite during five consecutive months.

Vauclair, S

2006-01-01

213

Exoplanet Characterization and the Search for Life  

CERN Multimedia

Over 300 extrasolar planets (exoplanets) have been detected orbiting nearby stars. We now hope to conduct a census of all planets around nearby stars and to characterize their atmospheres and surfaces with spectroscopy. Rocky planets within their star's habitable zones have the highest priority, as these have the potential to harbor life. Our science goal is to find and characterize all nearby exoplanets; this requires that we measure the mass, orbit, and spectroscopic signature of each one at visible and infrared wavelengths. The techniques for doing this are at hand today. Within the decade we could answer long-standing questions about the evolution and nature of other planetary systems, and we could search for clues as to whether life exists elsewhere in our galactic neighborhood.

Kasting, J; Roberge, A; Leger, A; Schwartz, A; Wooten, A; Vosteen, A; Lo, A; Brack, A; Tanner, A; Coustenis, A; Lane, B; Oppenheimer, B; Mennesson, B; Lopez, B; Grillmair, C; Beichman, C; Cockell, C; Hanot, C; McCarthy, C; Stark, C; Marois, C; Aime, C; Angerhausen, D; Montes, D; Wilner, D; Defrere, D; Mourard, D; Lin, D; Kite, E; Chassefiere, E; Malbet, F; Tian, F; Westall, F; Illingworth, G; Vasisht, G; Serabyn, G; Marcy, G; Bryden, G; White, G; Laughlin, G; Torres, G; Hammel, H; Ferguson, H; Shibai, H; Rottgering, H; Surdej, J; Wiseman, J; Ge, J; Bally, J; Krist, J; Monnier, J; Trauger, J; Horner, J; Catanzarite, J; Harrington, J; Nishikawa, J; Stapelfeldt, K; von Braun, K; Biazzo, K; Carpenter, K; Balasubramanian, K; Kaltenegger, L; Postman, M; Spaans, M; Turnbull, M; Levine, M; Burchell, M; Ealey, M; Kuchner, M; Marley, M; Dominik, M; Mountain, M; Kenworthy, M; Muterspaugh, M; Shao, M; Zhao, M; Tamura, M; Kasdin, N; Haghighipour, N; Kiang, N; Elias, N; Woolf, N; Mason, N; Absil, O; Guyon, O; Lay, O; Borde, P; Fouque, P; Kalas, P; Lowrance, P; Plavchan, P; Hinz, P; Kervella, P; Chen, P; Akeson, R; Soummer, R; Waters, R; Barry, R; Kendrick, R; Brown, R; Vanderbei, R; Woodruff, R; Danner, R; Allen, R; Polidan, R; Seager, S; MacPhee, S; Hosseini, S; Metchev, S; Kafka, S; Ridgway, S; Rinehart, S; Unwin, S; Shaklan, S; Brummelaar, T ten; Mazeh, T; Meadows, V; Weiss, W; Danchi, W; Ip, W; Rabbia, Y

2009-01-01

214

Deciphering spectral fingerprints of habitable exoplanets.  

UK PubMed Central (United Kingdom)

We discuss how to read a planet's spectrum to assess its habitability and search for the signatures of a biosphere. After a decade rich in giant exoplanet detections, observation techniques have advanced to a level where we now have the capability to find planets of less than 10 Earth masses (M(Earth)) (so-called "super Earths"), which may be habitable. How can we characterize those planets and assess whether they are habitable? This new field of exoplanet search has shown an extraordinary capacity to combine research in astrophysics, chemistry, biology, and geophysics into a new and exciting interdisciplinary approach to understanding our place in the Universe. The results of a first-generation mission will most likely generate an amazing scope of diverse planets that will set planet formation, evolution, and our planet into an overall context.

Kaltenegger L; Selsis F; Fridlund M; Lammer H; Beichman C; Danchi W; Eiroa C; Henning T; Herbst T; Léger A; Liseau R; Lunine J; Paresce F; Penny A; Quirrenbach A; Röttgering H; Schneider J; Stam D; Tinetti G; White GJ

2010-01-01

215

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

216

The far future of exoplanet direct characterization  

CERN Multimedia

In this outlook we describe what could be the next steps of the direct characterization of habitable exoplanets after first the medium and large mission projects and investigate the benefits of the spectroscopic and direct imaging approaches. We show that after third and fourth generation missions foreseeable for the next 100 years, we will face a very long era before being able to see directly the morphology of extrasolar organisms.

Schneider, Jean; Fridlund, Malcolm; White, Glenn; Eiroa, Carlos; Henning, Thomas; Herbst, Tom; Lammer, Helmut; Liseau, Rene; Paresce, Francesco; Penny, Alan; Quirrenbach, Andreas; Roettgering, Huub; Selsis, Franck; Beichman, Charles; Danchi, William; Kaltenegger, Lisa; Lunine, Jonathan; Stam, Daphne; Tinetti, Giovanna

2009-01-01

217

Mass-radius relationships for exoplanets  

CERN Multimedia

For planets other than Earth, and in particular for exoplanets, interpretation of the composition and structure depends largely on a comparison of the mass and radius with the composition expected given their distance from the parent star. The composition implies a mass-radius relation for different layers within the planet, which is based heavily on equations of state calculated from electronic structure theory and measured experimentally on Earth. We summarize current techniques for predicting and measuring equations of state, and calculate mass-radius relations for key materials for which the equation of state is reasonably well established, and for Fe-rock combinations. The relations are compared with the observed masses and radii of planets and exoplanets, broadly supporting recent inferences about exoplanet structures. CoRoT-7b probably has a rocky mantle over an Fe-based core. The core is likely to be proportionately smaller than the Earth's. GJ 1214b lies between the mass-radius curves for H_2Oand CH_...

Swift, Damian; Hicks, Damien; Hamel, Sebastien; Caspersen, Kyle; Schwegler, Eric; Collins, Gilbert; Ackland, Graeme

2010-01-01

218

Mass-Radius Relationships for Solid Exoplanets  

CERN Multimedia

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

219

THE FREQUENCY OF LOW-MASS EXOPLANETS  

International Nuclear Information System (INIS)

We report first results from the Anglo-Australian Telescope Rocky Planet Search-an intensive, high-precision Doppler planet search targeting low-mass exoplanets in contiguous 48 night observing blocks. On this run, we targeted 24 bright, nearby and intrinsically stable Sun-like stars selected from the Anglo-Australian Planet Search's main sample. These observations have already detected one low-mass planet reported elsewhere (HD 16417b), and here we reconfirm the detection of HD 4308b. Further, we have Monte Carlo simulated data from this run on a star-by-star basis to produce robust detection constraints. These simulations demonstrate clear differences in the exoplanet detectability functions from star to star due to differences in sampling, data quality and intrinsic stellar stability. They reinforce the importance of star-by-star simulation when interpreting the data from Doppler planet searches. These simulations indicate that for some of our target stars we are sensitive to close-orbiting planets as small as a few Earth masses. The two low-mass planets present in our 24-star sample indicate that the exoplanet minimum mass function at low masses is likely to be a flat ? ? -1 (for dN/dM ? M ?) and that between 15% ± 10% (at ? = -0.3) and 48% ± 34% (at ? = -1.3) of stars host planets with orbital periods of less than 16 days and minimum masses greater than 3 M +.

2009-08-20

220

THEORETICAL SPECTRA OF TERRESTRIAL EXOPLANET SURFACES  

International Nuclear Information System (INIS)

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 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 (Ag(K) – Ag(J)): Ag(K) – Ag(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; Ag(K) – Ag(J)

2012-06-10

 
 
 
 
221

Theoretical Spectra of Terrestrial Exoplanet Surfaces  

CERN Multimedia

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

222

TWO EXOPLANETS DISCOVERED AT KECK OBSERVATORY  

International Nuclear Information System (INIS)

We present two exoplanets detected at Keck Observatory. HD 179079 is a G5 subgiant that hosts a hot Neptune planet with M sin i = 27.5 M+ in a 14.48 days, low-eccentricity orbit. The stellar reflex velocity induced by this planet has a semiamplitude of K = 6.6 m s-1. HD 73534 is a G5 subgiant with a Jupiter-like planet of M sin i = 1.1 MJup and K = 16 m s-1 in a nearly circular 4.85 yr orbit. Both stars are chromospherically inactive and metal-rich. We discuss a known, classical bias in measuring eccentricities for orbits with velocity semiamplitudes, K, comparable to the radial velocity uncertainties. For exoplanets with periods longer than 10 days, the observed exoplanet eccentricity distribution is nearly flat for large amplitude systems (K > 80 m s-1), but rises linearly toward low eccentricity for lower amplitude systems (K > 20 m s-1).

2009-09-10

223

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

224

Transiting exoplanets from the CoRoT space mission I - CoRoT-Exo-1b: a low-density short-period planet around a G0V star  

CERN Multimedia

Context. The pioneer space mission for photometric planet searches, CoRoT, steadily monitors about 12,000 stars in each of its fields of view; it is able to detect transit candidates early in the processing of the data and before the end of a run. Aims. We report the detection of the first planet discovered by CoRoT and characterizing it with the help of follow-up observations. Methods. Raw data were filtered from outliers and residuals at the orbital period of the satellite. The orbital parameters and the radius of the planet were estimated by best fitting the phase folded light curve with 34 successive transits. Doppler measurements with the SOPHIE spectrograph permitted us to secure the detection and to estimate the planet mass. Results. The accuracy of the data is very high with a dispersion in the 2.17 min binned phase-folded light curve that does not exceed 3.10-4 in flux unit. The planet orbits a mildly metal-poor G0V star of magnitude V=13.6 in 1.5 days. The estimated mass and radius of the star are 0...

Barge, P; Auvergne, M; Rauer, H; Léger, A; Schneider, J; Pont, F; Aigrain, S; Almenara, J -M; Alonso, R; Barbieri, M; Borde, P; Bouchy, F; Deeg, H -J; De la Reza, R; Deleuil, M; Dvorak, R; Erikson, A; Fridlund, M; Gillon, M; Gondoin, P; Guillot, T; Hatzes, A; Hébrard, G; Jorda, L; Kabath, P; Lammer, H; Llebaria, A; Loeillet, B; Magain, P; Mazeh, T; Moutou, C; Ollivier, M; Patzold, M; Queloz, D; Rouan, D; Shporer, A; Wuchterl, G

2008-01-01

225

The Exoplanet Census: A General Method, Applied to Kepler  

CERN Multimedia

We develop a general method to fit the planetary distribution function (PLDF) to exoplanet survey data. This maximum likelihood method accommodates more than one planet per star and any number of planet or target star properties. Application to \\Kepler data relies on estimates of the efficiency of discovering transits around Solar type stars by Howard et al. (2011). These estimates are shown to agree with theoretical predictions for an ideal transit survey. Using announced \\Kepler planet candidates, we fit the PLDF as a joint powerlaw in planet radius, down to 0.5 R_Eart, and orbital period, up to 50 days. The estimated number of planets per star in this sample is ~ 0.7 --- 1.4, where the broad range covers systematic uncertainties in the detection efficiency. To analyze trends in the PLDF we consider four planet samples, divided between shorter and longer periods at 7 days and between large and small radii at 3 R_Earth. At longer periods, the size distribution of the small planets, with index \\alpha = -1.2 \\...

Youdin, Andrew N

2011-01-01

226

A Framework for Quantifying the Degeneracies of Exoplanet Interior Compositions  

CERN Multimedia

Several transiting super-Earths are expected to be discovered in the coming few years. While tools to model the interior structure of transiting planets exist, inferences about the composition are fraught with ambiguities. We present a framework to quantify how much we can robustly infer about super-Earth and Neptune-size exoplanet interiors from radius and mass measurements. We introduce quaternary diagrams to illustrate the range of possible interior compositions for planets with four layers (iron core, silicate mantles, water layers, and H/He envelopes). We apply our model to CoRoT-7b, GJ436b, and HAT-P-11b. Interpretation of planets with H/He envelopes is limited by the model uncertainty in the interior temperature, while for CoRoT-7b observational uncertainties dominate. We further find that our planet interior model sharpens the observational constraints on CoRoT-7b's mass and radius, assuming the planet does not contain significant amounts of water or gas. We show that the strength of the limits that c...

Rogers, L A

2009-01-01

227

BEST - The Balloon-borne Exoplanet Spectroscopy Telescope  

Science.gov (United States)

A 0.75-m, balloon-borne telescope operating in the stratosphere offers substantially enhanced detection of molecules in exoplanetary atmospheres. This is significant because molecules are powerful tracers of physical and chemical processes in these atmospheres. For instance, using the Hubble Space Telescope, our team has detected water, methane, carbon dioxide, and carbon monoxide in the atmosphere of a transiting hot-Jupiter exoplanet. Furthermore, we demonstrated that spectrally resolved observations of the primary and secondary eclipse provide information regarding the chemical compositions of distinct regions (terminator and dayside) of the atmosphere. Taking advantage of the stratosphere's drastically improved (compared to ground) seeing and infrared transparency, a balloon-borne telescope/infrared spectrometer optimized for instrument stability can substantially enhance wavelength coverage, spectral resolution, and temporal sampling. Moreover, it will fill in a critical gap between the spectral coverage of Spitzer and Hubble telescopes; the mid-infrared spectral regime probes fundamental vibrational transitions of molecules, and it is uniquely rich in molecular signatures. We show that such an instrument can be implemented with existing technology at modest cost to enable exciting "great observatory" class science.

Swain, Mark R.; Chen, P.; Vasisht, G.

2009-01-01

228

The science of exoplanets and their systems.  

UK PubMed Central (United Kingdom)

Abstract A scientific forum on "The Future Science of Exoplanets and Their Systems," sponsored by Europlanet (*) and the International Space Science Institute (ISSI) (†) and co-organized by the Center for Space and Habitability (CSH) (‡) of the University of Bern, was held during December 5 and 6, 2012, in Bern, Switzerland. It gathered 24 well-known specialists in exoplanetary, Solar System, and stellar science to discuss the future of the fast-expanding field of exoplanetary research, which now has nearly 1000 objects to analyze and compare and will develop even more quickly over the coming years. The forum discussions included a review of current observational knowledge, efforts for exoplanetary atmosphere characterization and their formation, water formation, atmospheric evolution, habitability aspects, and our understanding of how exoplanets interact with their stellar and galactic environment throughout their history. Several important and timely research areas of focus for further research efforts in the field were identified by the forum participants. These scientific topics are related to the origin and formation of water and its delivery to planetary bodies and the role of the disk in relation to planet formation, including constraints from observations as well as star-planet interaction processes and their consequences for atmosphere-magnetosphere environments, evolution, and habitability. The relevance of these research areas is outlined in this report, and possible themes for future ISSI workshops are identified that may be proposed by the international research community over the coming 2-3 years. Key Words: Exoplanets-Disks-Planet formation-Stellar activity-Water origin-Water delivery-Habitability. Astrobiology 13, 793-813.

Lammer H; Blanc M; Benz W; Fridlund M; Foresto VC; Güdel M; Rauer H; Udry S; Bonnet RM; Falanga M; Charbonneau D; Helled R; Kley W; Linsky J; Elkins-Tanton LT; Alibert Y; Chassefière E; Encrenaz T; Hatzes AP; Lin D; Liseau R; Lorenzen W; Raymond SN

2013-09-01

229

Terrestrial exoplanets: diversity, habitability and characterization  

Energy Technology Data Exchange (ETDEWEB)

After a decade rich in giant exoplanet detections, observation techniques have now reached the sensitivity to gain information on the physical structure and chemical content of some of the detected planets and also to find planets of less than 10 M{sub +}. The detection and characterization of Earth-like planets is approaching rapidly and dedicated space observatories are already in operation (CoRoT) or in the development phase (Kepler, Darwin and TPF-I/C). In this paper, we explore the domain of terrestrial planets, emphasizing habitable worlds. We discuss the possibility of performing a spectral characterization of their properties using the next generation of astronomical instruments.

Selsis, Franck [CRAL: Centre de Recherche Astrophysique de Lyon (CNRS), Universite de Lyon, Ecole Normale Superieure de Lyon, 46 allee d' Italie, F-69007 Lyon (France); Kaltenegger, Lisa [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Paillet, Jimmy [ESTEC SCI-SA, Keplerlaan 1, PO Box 299, 2200AG Noordwijk (Netherlands)], E-mail: franck.selsis@ens-lyon.fr, E-mail: lkaltene@cfa.harvard.edu, E-mail: jpaillet@rssd.esa.int

2008-08-15

230

Lithium abundances in exoplanet-hosts stars  

CERN Document Server

Exoplanet-host stars (EHS) are known to present surface chemical abundances different from those of stars without any detected planet (NEHS). EHS are, on the average, overmetallic compared to the Sun. The observations also show that, for cool stars, lithium is more depleted in EHS than in NEHS. The overmetallicity of EHS may be studied in the framework of two different scenarii. We have computed main sequence stellar models with various masses, metallicities and accretion rates. The results show different profiles for the lithium destruction according to the scenario. We compare these results to the spectroscopic observations of lithium.

Castro, M; Richard, O; Santos, N C

2008-01-01

231

Young Brown Dwarfs as Giant Exoplanet Analogs  

CERN Document Server

Young brown dwarfs and directly-imaged exoplanets have enticingly similar photometric and spectroscopic characteristics, indicating that their cool, low gravity atmospheres should be studied in concert. Similarities between the peculiar shaped H band, near and mid-IR photometry as well as location on color magnitude diagrams provide important clues about how to extract physical properties of planets from current brown dwarf observations. In this proceeding we discuss systems newly assigned to 10-150 Myr nearby moving groups, highlight the diversity of this uniform age-calibrated brown dwarf sample, and reflect on their implication for understanding current and future planetary data.

Faherty, Jacqueline K; Rice, Emily L; Riedel, Adric

2013-01-01

232

Polarimetry of the exoplanet system 51 Pegasi  

Science.gov (United States)

Two-year BVRI polarimetric monitoring of the exoplanet system 51 Peg has been carried out, indicating that there is no orbital phase-dependent periodic variability in linear polarization with amplitudes greater than 0.04% in the R and I bands. The mean value of one of the Stokes parameters is statistically significant and nonzero, being equal to 0.017 ± 0.004% when averaged over all the bands B, V, R, and I. The nonzero mean polarization can be due to light scattering by a circumstellar torus formed as a result of the mass loss by the hot Jupiter 51 Peg b.

Antonyuk, K. A.; Shakhovskoi, D. N.; Ksanfomaliti, L. V.

2013-05-01

233

Temporal variations in the evaporating atmosphere of the exoplanet HD 189733b  

CERN Document Server

Atmospheric escape has been detected from the exoplanet HD 209458b through transit observations of the hydrogen Lyman-alpha line. Here we present spectrally resolved Lyman-alpha transit observations of the exoplanet HD 189733b at two different epochs. These HST/STIS observations show for the first time, that there are significant temporal variations in the physical conditions of an evaporating planetary atmosphere. While atmospheric hydrogen is not detected in the first epoch observations, it is observed at the second epoch, producing a transit absorption depth of 14.4+/-3.6% between velocities of -230 to -140 km/s. Contrary to HD 209458b, these high velocities cannot arise from radiation pressure alone and require an additional acceleration mechanism, such as interactions with stellar wind protons. The observed absorption can be explained by an atmospheric escape rate of neutral hydrogen atoms of about 10^9 g/s, a stellar wind with a velocity of 190 km/s and a temperature of ~10^5K. An X-ray flare from the a...

Etangs, A Lecavelier des; Wheatley, P J; Dupuy, H; Ehrenreich, D; Vidal-Madjar, A; Hébrard, G; Ballester, G E; Désert, J -M; Ferlet, R; Sing, D K

2012-01-01

234

Data structures for ExoMol: Molecular line lists for exoplanet and other atmospheres  

Science.gov (United States)

At elevated temperatures the spectra of polyatomic molecules become extremely complicated with millions, or even billions, of transitions potentially playing an important role. The atmospheres of cool stars and ``hot Jupiter'' extrasolar planets are rich with molecules in the temperature range 1000 to 3000 K and their properties are strongly influenced by the infrared and visible spectra of these molecules. Access to extensive lists of transitions is essential for interpreting even the rather simple spectra that can be obtained from exoplanets. So far there are extensive, reliable lists of spectral lines for a number species including some stable diatomics, water and ammonia. Data are almost completely lacking for many key species such as methane. The ExoMol project aims to construct line lists of molecular transitions suitable for spectroscopic and atmospheric modelling of cool stars and exoplanets. At high temperatures it is necessary to consider huge numbers of lines even for a single species. Examples of line lists are given; data protocols defined and data handling issues which arise from trying to distribute these huge datasets discussed. In particular, a uniform but flexible format is given for the representation of line lists and cross sections resulting from the ExoMol project.

Tennyson, Jonathan; Hill, Christian; Yurchenko, Sergei N.

2013-07-01

235

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

CERN Multimedia

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

236

WASP-31b: a low-density planet transiting a late-F-type star  

CERN Multimedia

We report the discovery of the low-density, transiting giant planet WASP-31b. The planet is 0.47 Jupiter masses and 1.56 Jupiter radii. It is in a 3.4-day orbit around a 1-Gyr-old, late-F-type, V = 11.7 star, which is a member of a common proper motion pair. In terms of its low density, WASP-31b is second only to WASP-17b, which is a more highly irradiated planet of similar mass.

Anderson, D R; Hellier, C; Lendl, M; Lister, T A; Maxted, P F L; Queloz, D; Smalley, B; Smith, A M S; Triaud, A H M J; West, R G; Brown, D J A; Gillon, M; Pepe, F; Pollacco, D; Segransan, D; Street, R A; Udry, S

2010-01-01

237

WASP-30b: a 61 Mjup brown dwarf transiting a V=12, F8 star  

CERN Multimedia

We report the discovery of a 61-Jupiter-mass brown dwarf, which transits its F8V, rotationally-synchronised host star, WASP-30, every 4.16 days. From a range of age indicators, we estimate the system age to be 1-2 Gyr. We derive a radius (0.89 \\pm 0.02 RJup) for the companion that is consistent with that predicted (0.914 RJup) by a model of a 1-Gyr-old, non-irradiated brown dwarf with a dusty atmosphere.

Anderson, D R; Hellier, C; Lendl, M; Maxted, P F L; Pollacco, D; Queloz, D; Smalley, B; Smith, A M S; Todd, I; Triaud, A H M J; West, R G; Barros, S C C; Enoch, B; Gillon, M; Lister, T A; Pepe, F; Ségransan, D; Street, R A; Udry, S

2010-01-01

238

Debris Disks in Kepler Exoplanet Systems  

CERN Document Server

The Kepler Mission recently identified systems hosting candidate extrasolar planets, many of which are super-Earths. Realizing these rocky planetary systems are candidates to host extrasolar asteroid belts, we use mid-infrared data from the Wide-field Infrared Survey Explorer (WISE) to search for emission from dust in these systems. We find excesses around eight stars, indicating the presence of warm to hot dust (~100-500 K), corresponding to orbital distances of 0.1-10 AU for these solar-type stars. The strongest detection, KOI 1099, demands ~500 K dust interior to the orbit of its exoplanet candidate. One star, KOI 904, may host very hot dust (~1200 K, corresponding to 0.02 AU). We find the fraction of these exoplanet-bearing stars with warm excesses (~3%) is consistent with the fraction found for solar-type field stars. It is difficult to explain the presence of dust so close to the host stars, corresponding to dust rings at radii <0.3 AU; both the collisional and Poynting-Robertson drag timescales to r...

Lawler, S M

2011-01-01

239

DEBRIS DISKS IN KEPLER EXOPLANET SYSTEMS  

International Nuclear Information System (INIS)

[en] The Kepler mission recently identified 997 systems hosting candidate extrasolar planets, many of which are super-Earths. Realizing these planetary systems are candidates to host extrasolar asteroid belts, we use mid-infrared data from the Wide-field Infrared Survey Explorer (WISE) to search for emission from dust in these systems. We find excesses around eight stars, indicating the presence of warm to hot dust (?100-500 K), corresponding to orbital distances of 0.1-10 AU for these solar-type stars. The strongest detection, KOI 1099, demands ?500 K dust interior to the orbit of its exoplanet candidate. One star, KOI 904, may host very hot dust (?1200 K, corresponding to 0.02 AU). Although the fraction of these exoplanet-bearing stars with detectable warm excesses (?3%) is similar to that found by Spitzer surveys of solar-type field stars, the excesses detectable in the WISE data have much higher fractional luminosities (Ldust/L*) than most known debris disks, implying that the fraction with debris disks of comparable luminosity may actually be significantly higher. It is difficult to explain the presence of dust so close to the host stars, generally corresponding to dust rings at radii

2012-06-10

240

Exoplanet Curriculum at the International Space University  

Science.gov (United States)

Rapidly-expanding knowledge of exoplanets is providing a huge opportunity for education at all levels. In addition to the intrinsic scientific interest of finding other planetary systems and developing testable hypotheses about stellar evolution, based for the first time in history on more than one example, there is the prospect of finding habitats for other life. Even if actual life signatures cannot yet be unambiguously detected, just a credible possibility is enough to catalyze new discussions and stimulate new ideas emerging from the rich background of science fiction and the ancient concept of a plurality of inhabited worlds. At the International Space University, a graduate-level institution devoted to identifying, informing and encouraging young professionals from throughout the world, this exploding new field of science provides a grand opportunity for seminars and other activities engaging students in creative thinking about the vast human implications of a populated cosmos. Once a planet's existence and orbit are confirmed by long-continued observations, it may be a suitable object for spectrometry and other techniques to begin finding characteristics of its interior, atmosphere, magnetosphere, possibly even oceans. These observations require not only very advanced instrumentation and data methods but also patience and skill in operations both on Earth and in space. They can serve as an organizing principle for education across all of the specialties represented at ISU. In this paper we discuss the ISU curriculum, focusing on those parts of it that can benefit from the interdisciplinary expansion enabled by exoplanet discoveries.

Burke, J. D.; Hill, H. G. M.

2012-04-01

 
 
 
 
241

NFIRAOS High-Contrast Exoplanet Imaging Capabilities  

Science.gov (United States)

The TMT offers great potential to find and study nearby planetary systems, possibly imaging down to super-Earth size planets or still accreting distant planets in very young star forming regions. Since no first generation dedicated exoplanet finding instruments have been selected, initial direct exoplanet imaging will have to rely on the NFIRAOS facility AO system. I will present end-to-end Fresnel NFIRAOS simulations using its current optical design to evaluate its multi-wavelength high-contrast imaging capabilities. Long exposures have been simulated using the expected AO-delivered phase screens and the estimated speckle lifetime. It is shown that NFIRAOS will offer contrasts comparable to GPI (an optimized NIR planet-finding instrument that will soon be installed on the Gemini South 8-m telescope). Without coronograph and higher order correction, NFIRAOS will not be able to achieve high contrast at very small IWA, which are potentially accessible with a 30-meter telescope. However, TMT, with its larger aperture and better angular resolution, will acquire higher SNR planet spectra and will achieve an astrometric accuracy three times smaller than GPI, resulting in better atmospheric characterization and faster orbital parameters determination.

Marois, Christian; Veran, Jean-Pierre

2011-09-01

242

LIGHT SCATTERING FROM EXOPLANET OCEANS AND ATMOSPHERES  

International Nuclear Information System (INIS)

Orbital variation in reflected starlight from exoplanets could eventually be used to detect surface oceans. Exoplanets with rough surfaces, or dominated by atmospheric Rayleigh scattering, should reach peak brightness in full phase, orbital longitude (OL) = 1800, whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 300. Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak polarization fraction of 1 at OL = 740; however, our model shows that clouds, wind-driven waves, aerosols, absorption, and Rayleigh scattering in the atmosphere and within the water column dilute the polarization fraction and shift the peak to other OLs. Observing at longer wavelengths reduces the obfuscation of the water polarization signature by Rayleigh scattering but does not mitigate the other effects. Planets with thick Rayleigh scattering atmospheres reach peak polarization near OL = 900, but clouds and Lambertian surface scattering dilute and shift this peak to smaller OL. A shifted Rayleigh peak might be mistaken for a water signature unless data from multiple wavelength bands are available. Our calculations suggest that polarization alone may not positively identify the presence of an ocean under an Earth-like atmosphere; however, polarization adds another dimension which can be used, in combination with unpolarized orbital light curves and contrast ratios, to detect extrasolar oceans, atmospheric water aerosols, and water clouds. Additionally, the presence and direction of the polarization vector could be used to determine planet association with the star, and constrain orbit inclination.

2010-11-10

243

Exoplanet Searches by Future Deep Space Missions  

Directory of Open Access Journals (Sweden)

Full Text Available The search for exoplanets could bene?t from gravitational lensing if we could get to 550 AU from the Sun and beyond. This is because the gravitational lens of the Sun would highly intensify there any weak electromagnetic wave reaching the solar system from distant planets in the Galaxy (see Maccone 2009). The gravitational lens of the Sun, however, has a drawback: the solar Corona. Electrons in the Corona make electromagnetic waves diverge and this pushes the focus out to distances higher than 550 AU. Jupiter is the second larger mass in the solar system after the Sun, but in this focal game not only the mass matters: rather, what really matters is the ratio between the radius of the body squared and the mass of the body. In this regard, Jupiter quali?es as the second best choice for a space mission, requiring the spacecraft to reach 6,077 AU. In this paper, we study the bene?t of exoplanet searches by deep space missions.

Maccone C.

2011-01-01

244

Abundance Stratification of Exoplanet Host Stars  

CERN Multimedia

Aims: To determine Sigma (variation of Fe abundance with the optical depth), tau{FeI}, tau{FeII} (Rosseland median optical depth of Fe lines) and Delta[Fe/H](=[FeI/H]-[FeII/H]), in 79 Exoplanet Host stars (66 main sequence and 13 giants), with respect to 322 solar neighborhood field stars (9 main sequence and 313 giant stars). Methods: We derived FeI and FeII abundances using equivalent width measurements together with ATLAS9 (Kurucz 1993) model atmospheres and the WIDTH9 program. Results: The Rosseland median optical depths tau{FeI} and tau{FeII} are dependent on stellar parameters (log g, T{eff} and xi). We conclude that Sigma is a more reliable stratification indicator than tau{FeI}, tau{FeII} and Delta[Fe/H]. Our results show that statistically most EH stars (main sequence and giants) have an stratification similar to field stars, which is in agreement with the primordial hyphotesis of metal enhancement. The lack of correlation between Sigma and the exoplanet parameters (minimum mass, semiaxis and eccentr...

Saffe, C; López-García, Z; Jofre, E; Petrucci, R; González, E

2008-01-01

245

Galactic cosmic ray induced radiation dose on terrestrial exoplanets  

CERN Multimedia

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

246

The effects of stellar winds and magnetic fields on exoplanets  

CERN Document Server

The great majority of exoplanets discovered so far are orbiting cool, low-mass stars whose properties are relatively similar to the Sun. However, the stellar magnetism of these stars can be significantly different from the solar one, both in topology and intensity. In addition, due to the present-day technology used in exoplanetary searches, most of the currently known exoplanets are found orbiting at extremely close distances to their host stars ($< 0.1$ au). The dramatic differences in stellar magnetism and orbital radius can make the interplanetary medium of exoplanetary systems remarkably distinct from that of the Solar System. To constrain interactions between exoplanets and their host-star's magnetised winds and to characterise the interplanetary medium that surrounds exoplanets, more realistic stellar wind models, which account for factors such as stellar rotation and the complex stellar magnetic field configurations of cool stars, must be employed. Here, I briefly review the latest progress made in...

Vidotto, A A

2013-01-01

247

ExELS: an exoplanet legacy science proposal for the ESA Euclid mission I. Cold exoplanets  

CERN Document Server

The Euclid mission is the second M-class mission of the ESA Cosmic Vision programme, with the principal science goal of studying dark energy through observations of weak lensing and baryon acoustic oscillations. Euclid is also expected to undertake additional Legacy Science programmes. One such proposal is the Exoplanet Euclid Legacy Survey (ExELS) which will be the first survey able to measure the abundance of exoplanets down to Earth mass for host separations from ~1 AU out to the free-floating (unbound) regime. The cold and free-floating exoplanet regimes represent a crucial discovery space for testing planet formation theories. ExELS will use the gravitational microlensing technique and will detect over 400 microlensing events per month over 1.6 deg^2 of the Galactic bulge. We assess how many of these events will have detectable planetary signatures using a detailed multi-wavelength microlensing simulator --- the Manchester-Besancon microLensing Simulator (MaBuLS) --- which incorporates the Besancon Galac...

Penny, M T; Rattenbury, N; Beaulieu, J -P; Robin, A C; Mao, S; Batista, V; Novati, S Calchi; Cassan, A; Fouque, P; McDonald, I; Marquette, J B; Tisserand, P; Osorio, M R Zapatero

2012-01-01

248

Astrometry and Exoplanets: the Gaia Era, and Beyond  

CERN Multimedia

The wealth of information in the Gaia catalogue of exoplanets will constitute a fundamental contribution to several hot topics of the astrophysics of planetary systems. I briefly review the potential impact of Gaia micro-arsec astrometry in several areas of exoplanet science, discuss what key follow-up observations might be required as a complement to Gaia data, and shed some light on the role of next generation astrometric facilities in the arena of planetary systems.

Sozzetti, A

2010-01-01

249

CYCLIC TRANSIT PROBABILITIES OF LONG-PERIOD ECCENTRIC PLANETS DUE TO PERIASTRON PRECESSION  

Energy Technology Data Exchange (ETDEWEB)

The observed properties of transiting exoplanets are an exceptionally rich source of information that allows us to understand and characterize their physical properties. Unfortunately, only a relatively small fraction of the known exoplanets discovered using the radial velocity technique are known to transit their host due to the stringent orbital geometry requirements. For each target, the transit probability and predicted transit time can be calculated to great accuracy with refinement of the orbital parameters. However, the transit probability of short period and eccentric orbits can have a reasonable time dependence due to the effects of apsidal and nodal precession, thus altering their transit potential and predicted transit time. Here we investigate the magnitude of these precession effects on transit probabilities and apply this to the known radial velocity exoplanets. We assess the refinement of orbital parameters as a path to measuring these precessions and cyclic transit probabilities.

Kane, Stephen R.; Von Braun, Kaspar [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Horner, Jonathan, E-mail: skane@ipac.caltech.edu [Department of Astrophysics and Optics, School of Physics, University of New South Wales, Sydney 2052 (Australia)

2012-09-20

250

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

Science.gov (United States)

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.

2013-05-01

251

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

International Nuclear Information System (INIS)

[en] 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.

2013-05-01

252

MASS-RADIUS RELATIONSHIPS FOR EXOPLANETS  

International Nuclear Information System (INIS)

For planets other than Earth, particularly exoplanets, interpretation of the composition and structure depends largely on comparing the mass and radius with the composition expected given their distance from the parent star. The composition implies a mass-radius relation which relies heavily on equations of state calculated from electronic structure theory and measured experimentally on Earth. We lay out a method for deriving and testing equations of state, and deduce mass-radius and mass-pressure relations for key, relevant materials whose equation of state (EOS) is reasonably well established, and for differentiated Fe/rock. We find that variations in the EOS, such as may arise when extrapolating from low-pressure data, can have significant effects on predicted mass-radius relations and on planetary pressure profiles. The relations are compared with the observed masses and radii of planets and exoplanets, broadly supporting recent inferences about exoplanet structures. Kepler-10b is apparently 'Earth-like', likely with a proportionately larger core than Earth's, nominally 2/3 of the mass of the planet. CoRoT-7b is consistent with a rocky mantle over an Fe-based core which is likely to be proportionately smaller than Earth's. GJ 1214b lies between the mass-radius curves for H2O and CH4, suggesting an 'icy' composition with a relatively large core or a relatively large proportion of H2O. CoRoT-2b is less dense than the hydrogen relation, which could be explained by an anomalously high degree of heating or by higher than assumed atmospheric opacity. HAT-P-2b is slightly denser than the mass-radius relation for hydrogen, suggesting the presence of a significant amount of matter of higher atomic number. CoRoT-3b lies close to the hydrogen relation. The pressure at the center of Kepler-10b is 1.5+1.2–1.0 TPa. The central pressure in CoRoT-7b is probably close to 0.8 TPa, though may be up to 2 TPa. These pressures are accessible by planar shock and ramp-loading experiments at large laser facilities. The center of HAT-P-2b is probably around 210 TPa, in the range of planned National Ignition Facility experiments, and that of CoRoT-3b around 1900 TPa.

2012-01-01

253

Two nearby sub-Earth-sized exoplanet candidates in the GJ 436 system  

CERN Document Server

We report the detection of UCF-1.01, a strong exoplanet candidate with a radius 0.66 +/- 0.04 times that of Earth (R_{\\oplus}). This sub-Earth-sized planet transits the nearby M-dwarf star GJ 436 with a period of 1.365862 +/- 8x10^{-6} days. We also report evidence of a 0.65 +/- 0.06 R_{\\oplus} exoplanet candidate (labeled UCF-1.02) orbiting the same star with an undetermined period. Using the Spitzer Space Telescope, we measure the dimming of light as the planets pass in front of their parent star to assess their sizes and orbital parameters. If confirmed, UCF-1.01 and UCF-1.02 would be called GJ 436c and GJ 436d, respectively, and would be part of the first multiple-transiting-planet system outside of the Kepler field. Assuming Earth-like densities of 5.515 g/cm^3, we predict both candidates to have similar masses (~0.28 Earth-masses, M_{\\oplus}, 2.6 Mars-masses) and surface gravities of ~0.65 g (where g is the gravity on Earth). UCF-1.01's equilibrium temperature (T_{eq}, where emitted and absorbed radiati...

Stevenson, Kevin B; Lust, Nate B; Lewis, Nikole K; Montagnier, Guillaume; Moses, Julianne I; Visscher, Channon; Blecic, Jasmina; Hardy, Ryan A; Cubillos, Patricio; Campo, Christopher J

2012-01-01

254

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

255

Exomol: Molecular Line Lists for Exoplanet and Other Atmospheres  

Science.gov (United States)

Spectral characterization of astrophysical objects cool enough to form molecules in their atmospheres (cool stars, extrosolar planets and planetary discs) requires considerable amounts of fundamental molecular data. The existing molecular line lists (with some exceptions) are generally not sufficiently accurate and complete. The ExoMol project is actively generating comprehensive line lists for all molecules likely to be observable in exoplanet atmospheres in the foreseeable future. This is a huge undertaking which will mean providing in excess of 10^{11} spectral lines for a large variety of molecular species, see Tennyson and Yurchenko (Mon. Not. R. Astron. Soc., 425, 21 (2012)) The physics of molecular absorptions is complex and varies between different classes of absorbers. The project is therefore be divided into following topics (a) diatomic, (b) triatomics, (c) tetratomics, (d) methane and (e) larger molecules. Special techniques are being developed to treat each case. The majority of diatomic systems to be tackled are open shell species involving a transition metal atom; the opacity is provided by the transitions between the many low lying electronic states of the system. The calculation of rotation-vibration line lists for closed-shell triatomic systems is now relatively straightforward provided enough care is taken in deriving the potential energy and dipole surfaces. An H_2S line list is nearing completion and studies on C_3 have started. Accurate rotation-vibration line lists for hot tetratomic molecules such as ammonia (complete), phosphine (nearing completion), acetylene (initial study published), hydrogen peroxide (initial study complete), SO_3 (room temperature line list complete) and formaldehyde, test what is computationally possible at present. An inital line list for hot (1000 K) methane has been completed and is being improved. Work on systems larger than this is just commencing. Data from this project can be accessed at www.exomol.com.

Tennyson, Jonathan

2013-06-01

256

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

257

A sub-Mercury-sized exoplanet  

CERN Multimedia

Since the discovery of the first exoplanet we have known that other planetary systems can look quite unlike our own. However, until recently we have only been able to probe the upper range of the planet size distribution. The high precision of the Kepler space telescope has allowed us to detect planets that are the size of Earth and somewhat smaller, but no previous planets have been found that are smaller than those we see in our own Solar System. Here we report the discovery of a planet significantly smaller than Mercury. This tiny planet is the innermost of three planets that orbit the Sun-like host star, which we have designated Kepler-37. Owing to its extremely small size, similar to that of Earth's Moon, and highly irradiated surface, Kepler-37b is probably a rocky planet with no atmosphere or water, similar to Mercury.

Barclay, Thomas; Lissauer, Jack J; Huber, Daniel; Fressin, Francois; Howell, Steve B; Bryson, Stephen T; Chaplin, William J; Désert, Jean-Michel; Lopez, Eric D; Marcy, Geoffrey W; Mullally, Fergal; Ragozzine, Darin; Torres, Guillermo; Adams, Elisabeth R; Agol, Eric; Barrado, David; Basu, Sarbani; Bedding, Timothy R; Buchhave, Lars A; Charbonneau, David; Christiansen, Jessie L; Christensen-Dalsgaard, Jørgen; Ciardi, David; Cochran, William D; Dupree, Andrea K; Elsworth, Yvonne; Everett, Mark; Fischer, Debra A; Ford, Eric B; Fortney, Jonathan J; Geary, John C; Haas, Michael R; Handberg, Rasmus; Hekker, Saskia; Henze, Christopher E; Horch, Elliott; Howard, Andrew W; Hunter, Roger C; Isaacson, Howard; Jenkins, Jon M; Karoff, Christoffer; Kawaler, Steven D; Kjeldsen, Hans; Klaus, Todd C; Latham, David W; Li, Jie; Lillo-Box, Jorge; Lund, Mikkel N; Lundkvist, Mia; Metcalfe, Travis S; Miglio, Andrea; Morris, Robert L; Quintana, Elisa V; Stello, Dennis; Smith, Jeffrey C; Still, Martin; Thompson, Susan E

2013-01-01

258

A sub-Mercury-sized exoplanet.  

UK PubMed Central (United Kingdom)

Since the discovery of the first exoplanets, it has been known that other planetary systems can look quite unlike our own. Until fairly recently, we have been able to probe only the upper range of the planet size distribution, and, since last year, to detect planets that are the size of Earth or somewhat smaller. Hitherto, no planets have been found that are smaller than those we see in the Solar System. Here we report a planet significantly smaller than Mercury. This tiny planet is the innermost of three that orbit the Sun-like host star, which we have designated Kepler-37. Owing to its extremely small size, similar to that of the Moon, and highly irradiated surface, the planet, Kepler-37b, is probably rocky with no atmosphere or water, similar to Mercury.

Barclay T; Rowe JF; Lissauer JJ; Huber D; Fressin F; Howell SB; Bryson ST; Chaplin WJ; Désert JM; Lopez ED; Marcy GW; Mullally F; Ragozzine D; Torres G; Adams ER; Agol E; Barrado D; Basu S; Bedding TR; Buchhave LA; Charbonneau D; Christiansen JL; Christensen-Dalsgaard J; Ciardi D; Cochran WD; Dupree AK; Elsworth Y; Everett M; Fischer DA; Ford EB; Fortney JJ; Geary JC; Haas MR; Handberg R; Hekker S; Henze CE; Horch E; Howard AW; Hunter RC; Isaacson H; Jenkins JM; Karoff C; Kawaler SD; Kjeldsen H; Klaus TC; Latham DW; Li J; Lillo-Box J; Lund MN; Lundkvist M; Metcalfe TS; Miglio A; Morris RL; Quintana EV; Stello D; Smith JC; Still M; Thompson SE

2013-02-01

259

DEBRIS DISKS IN KEPLER EXOPLANET SYSTEMS  

Energy Technology Data Exchange (ETDEWEB)

The Kepler mission recently identified 997 systems hosting candidate extrasolar planets, many of which are super-Earths. Realizing these planetary systems are candidates to host extrasolar asteroid belts, we use mid-infrared data from the Wide-field Infrared Survey Explorer (WISE) to search for emission from dust in these systems. We find excesses around eight stars, indicating the presence of warm to hot dust ({approx}100-500 K), corresponding to orbital distances of 0.1-10 AU for these solar-type stars. The strongest detection, KOI 1099, demands {approx}500 K dust interior to the orbit of its exoplanet candidate. One star, KOI 904, may host very hot dust ({approx}1200 K, corresponding to 0.02 AU). Although the fraction of these exoplanet-bearing stars with detectable warm excesses ({approx}3%) is similar to that found by Spitzer surveys of solar-type field stars, the excesses detectable in the WISE data have much higher fractional luminosities (L{sub dust}/L{sub *}) than most known debris disks, implying that the fraction with debris disks of comparable luminosity may actually be significantly higher. It is difficult to explain the presence of dust so close to the host stars, generally corresponding to dust rings at radii <0.3 AU; both the collisional and Poynting-Robertson drag timescales to remove dust from the system are hundreds of years or less at these distances. Assuming a steady state for these systems implies large mass consumption rates with these short removal timescales, meaning that the dust production mechanism in these systems must almost certainly be episodic in nature.

Lawler, S. M.; Gladman, B. [Department of Physics and Astronomy, University of British Columbia, 6244 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada)

2012-06-10

260

Effect of Clouds on Exoplanet Visible-Wavelength Phase Curve Observations  

Science.gov (United States)

We investigate the effect of clouds in hot Jupiter atmospheres on the observations of transiting exoplanets. We consider how non-uniformity in cloud coverage on hot Jupiters may affect the reflectance spectra and resulting phase curve. Hot Jupiters are Jovian-sized exoplanets orbiting close to their parent star. The predicted temperatures at these close separations generally would not support cloud formation. However, tidal locking will create a permanent day-side and night-side with large temperature, pressure, and species-state contrasts that might favor cloud formation on the night-side. A rapid eastward equatorial flow of hot-Jupiter atmospheres has been well studied and observed. This jet causes the hottest and coldest parts of the atmosphere to be misaligned from the substellar and anti-stellar points. This misalignment can be seen as an offset in the infrared phase curve maximum from the secondary eclipse. The addition of clouds into this complex thermal and advective system will change the albedo spectra of the planet and the phase curve of reflected intensity. The current state of exoplanet atmospheric modeling couples radiative transfer with the dynamics of the atmosphere. Our albedo model inputs temperature and pressure profiles from radiative-convective simulations to produce albedo spectra in the visible wavelengths based on parameters that include planet-star separation, gravity, metallicity, and source-observer geometry. Optical phase curves are produced from these albedo spectra in a variety of filters. We first test this method on a Jupiter-like model with a 90° misalignment, resulting in a dayside that is half cloudy. This misalignment manifests as a large shift of the phase curve maximum because of the increased reflectivity of the cloud-covered area. The model is then extended to a 30° misalignment similar to what is expected for optical observations of an HD189733b-like planet.

Webber, Matthew W.; Lewis, N.; Marley, M.; Fortney, J.; Cahoy, K.

2013-10-01

 
 
 
 
261

Characterizing Exoplanets in the Visible and Infrared: A Spectrometer Concept for the EChO Space Mission  

CERN Multimedia

Transit-spectroscopy of exoplanets is one of the key observational techniques to characterize the extrasolar planet and its atmosphere. The observational challenges of these measurements require dedicated instrumentation and only the space environment allows an undisturbed access to earth-like atmospheric features such as water or carbon-dioxide. Therefore, several exoplanet-specific space missions are currently being studied. One of them is EChO, the Exoplanet Characterization Observatory, which is part of ESA's Cosmic Vision 2015-2025 program, and which is one of four candidates for the M3 launch slot in 2024. In this paper we present the results of our assessment study of the EChO spectrometer, the only science instrument onboard this spacecraft. The instrument is a multi-channel all-reflective dispersive spectrometer, covering the wavelength range from 400 nm to 16 microns simultaneously with a moderately low spectral resolution. We illustrate how the key technical challenge of the EChO mission - the high...

Glauser, A M; Krause, O; Henning, Th; Benneke, B; Bouwman, J; Cubillos, P E; Crossfield, I J M; Detre, Ö H; Ebert, M; Grözinger, U; Güdel, M; Harrington, J; Justtanont, K; Klaas, U; Lenzen, R; Madhusudhan, N; Meyer, M R; Mordasini, C; Müller, F; Ottensamer, R; Plesseria, J -Y; Quanz, S P; Reiners, A; Renotte, E; Rohloff, R -R; Scheithauer, S; Schmid, H M; Schrader, J -R; Seemann, U; Stam, D; Vandenbussche, B; Wehmeier, U

2013-01-01

262

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

Science.gov (United States)

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 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 (~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 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. Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

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

2013-05-01

263

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

264

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

International Nuclear Information System (INIS)

[en] 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]), 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 (?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 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.

2013-05-01

265

An exoplanet in orbit around tau^1 Gruis  

CERN Multimedia

We report the detection of a new candidate exoplanet around the metal-rich star tau^1 Gruis. With M sin $i$ = 1.23+/-0.18 M_JUP, a period of 1326+/-300 d and an orbit with an eccentricity of 0.14+/-0.14 it adds to the growing population of long period exoplanets with near-circular orbits. This population now comprises more than 20% of known exoplanets. When the companion to tau^1 Gruis is plotted together with all exoplanets found by the Anglo-Australian Planet Search and other radial velocity searches we find evidence for a peak in the number of short-period exoplanets, followed by a minimum of planets between around 7 and 50 days and then an apparent rise in the number of planets per unit radius that seems to set in by a hundred days, indicating more planets farther from the host star. This is very different from the gaussian-like period distribution found for stellar companions. This lends support to the idea that once a clearing in the inner protoplanetary disk develops, it halts the inward migration of p...

Jones, H R A; Tinney, C G; Marcy, G W; Penny, A J; McCarthy, C; Carter, B D; Jones, Hugh R.A.; Tinney, Chris G.; Marcy, Geoff W.; Penny, Alan J.; Carthy, Chris Mc; Carter, Brad D.

2003-01-01

266

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

267

ON THE ORBIT OF EXOPLANET WASP-12b  

International Nuclear Information System (INIS)

We observed two secondary eclipses of the exoplanet WASP-12b using the Infrared Array Camera on the Spitzer Space Telescope. The close proximity of WASP-12b to its G-type star results in extreme tidal forces capable of inducing apsidal precession with a period as short as a few decades. This precession would be measurable if the orbit had a significant eccentricity, leading to an estimate of the tidal Love number and an assessment of the degree of central concentration in the planetary interior. An initial ground-based secondary-eclipse phase reported by Lopez-Morales et al. (0.510 ± 0.002) implied eccentricity at the 4.5? level. The spectroscopic orbit of Hebb et al. has eccentricity 0.049 ± 0.015, a 3? result, implying an eclipse phase of 0.509 ± 0.007. However, there is a well-documented tendency of spectroscopic data to overestimate small eccentricities. Our eclipse phases are 0.5010 ± 0.0006 (3.6 and 5.8 ?m) and 0.5006 ± 0.0007 (4.5 and 8.0 ?m). An unlikely orbital precession scenario invoking an alignment of the orbit during the Spitzer observations could have explained this apparent discrepancy, but the final eclipse phase of Lopez-Morales et al. (0.510 ±+0.007-0.006) is consistent with a circular orbit at better than 2?. An orbit fit to all the available transit, eclipse, and radial-velocity data indicates precession at

2011-02-01

268

Insolation on exoplanets with eccentricity and obliquity  

Science.gov (United States)

The pattern of insolation on an extrasolar planet has profound implications for its climate and habitability. A planet's insolation regime depends on its orbital eccentricity, the obliquity of its spin axis, its rotation rate, and its longitude of vernal equinox. For example, although a planet receives the same time-averaged insolation at both poles, the peak insolation at its poles can differ by a factor up to 27, depending on its eccentricity and equinox. This is of particular interest for planets with polar icecaps (or lakes and seas), like Mercury, Earth, and Mars (or Titan). The nearly 600 exoplanets now with known eccentricities span a wide range of eccentricity from essentially zero up to near unity; but their obliquities are still unknown, and also may range widely. Including both non-zero eccentricity and obliquity together vastly broadens the variety of global insolation patterns on extrasolar planets. This applies especially to planets in synchronous rotation, or in other spin-orbit resonances (like Mercury), which can exhibit quite complicated and unusual insolation patterns. For example, regions of eternal daylight and endless night occur only on synchronous exoplanets, whose rotation periods equal their orbital periods; but the peak and time-averaged insolation can vary by factors of at least 32 and 88, respectively, over a planet with a rotation period of half its orbital period, an eccentricity of 0.20, and an obliquity of 60°. Patterns of both mean and peak insolation display various symmetries with respect to latitude and longitude on the planet's surface. Most of these are relatively simple and easily understood; for example, a resonant planet whose orbital period is half of an odd multiple of its rotation period (as in Mercury's 3/2 resonance) experiences identical insolation patterns at longitudes 180° apart. However, such half-odd resonances also exhibit a totally unexpected symmetry of the time-averaged insolation with respect to the planet's equator, not shared by the peak insolation, or by any whole-number resonances. This emergent symmetry can be understood by Fourier analysis of the time-varying insolation.

Dobrovolskis, Anthony R.

2013-09-01

269

The WFC3 Galactic Bulge Treasury Program: Metallicity Estimates for the Stellar Population and Exoplanet Hosts  

CERN Document Server

We present new UV-to-IR stellar photometry of four low-extinction windows in the Galactic bulge, obtained with the Wide Field Camera 3 on the Hubble Space Telescope (HST). Using our five bandpasses, we have defined reddening-free photometric indices sensitive to stellar effective temperature and metallicity. We find that the bulge populations resemble those formed via classical dissipative collapse: each field is dominated by an old (~10 Gyr) population exhibiting a wide metallicity range (-1.5 < [Fe/H] < 0.5). We detect a metallicity gradient in the bulge population, with the fraction of stars at super-solar metallicities dropping from 41% to 35% over distances from the Galactic center ranging from 0.3 to 1.2 kpc. One field includes candidate exoplanet hosts discovered in the SWEEPS HST transit survey. Our measurements for 11 of these hosts demonstrate that exoplanets in the distinct bulge environment are preferentially found around high-metallicity stars, as in the solar neighborhood, supporting the v...

Brown, Thomas M; Anderson, Jay; Tumlinson, Jason; Valenti, Jeff A; Smith, Ed; Jeffery, Elizabeth J; Renzini, Alvio; Zoccali, Manuela; Ferguson, Henry C; VandenBerg, Don A; Bond, Howard E; Casertano, Stefano; Valenti, Elena; Minniti, Dante; Livio, Mario; Panagia, Nino

2010-01-01

270

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

CERN Multimedia

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

271

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

Science.gov (United States)

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, the first transiting planet in the Kepler field.

O'Donovan, F. T.; Charbonneau, D.

2007-07-01

272

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 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

273

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

274

On the Ages of Exoplanet Host Stars  

CERN Multimedia

We obtained spectra, covering the CaII H and K region, for 49 exoplanet host (EH) stars, observable from the southern hemisphere. We measured the chromospheric activity index, Rhk. We compiled previously published values of this index for the observed objects as well as the remaining EH stars in an effort to better smooth temporal variations and derive a more representative value of the average chromospheric activity for each object. We used the average index to obtain ages for the group of EH stars. In addition we applied other methods, such as: Isochrone, lithium abundance, metallicity and transverse velocity dispersions, to compare with the chromospheric results. The kinematic method is a less reliable age estimator because EH stars lie red-ward of Parenago's discontinuity in the transverse velocity dispersion vs dereddened B-V diagram. The chromospheric and isochrone techniques give median ages of 5.2 and 7.4 Gyr, respectively, with a dispersion of 4 Gyr. The median age of F and G EH stars derived by the ...

Saffe, C; Chavero, C

2005-01-01

275

A Metric for Exo-Planet Detectability  

Science.gov (United States)

There are many architectures being proposed for direct imaging of planets around other stars. To compare the performance of these systems, we need a consistent metric to quantify whether and how well a given planet or range of planets can be observed. This is also critical for deriving a specific mission design for a given architecture. In this paper, we look at this issue in the context of the New Worlds Observer (NWO) architecture. We develop a metric for how well a given planet can be seen by a given system. We then apply this metric to a range of NWO systems and explore how this affects the mission design. We find that the central starlight suppression and the geometrical Inner Working Angle (IWA) are not good ways to describe an external occulter system's ability to detect an exo-planet. Instead, for a given mission design, there will be a range of IWA depending on the relationship between the planet brightness and the suppression provided by the starshade. We explore this relationship and discuss its implications for the design of an NWO mission.

Glassman, Tiffany M.; Polidan, R.; Lo, A.

2007-12-01

276

TIDALLY HEATED TERRESTRIAL EXOPLANETS: VISCOELASTIC RESPONSE MODELS  

International Nuclear Information System (INIS)

Tidal friction in exoplanet systems, driven by orbits that allow for durable nonzero eccentricities at short heliocentric periods, can generate internal heating far in excess of the conditions observed in our own solar system. Secular perturbations or a notional 2:1 resonance between a hot Earth and hot Jupiter can be used as a baseline to consider the thermal evolution of convecting bodies subject to strong viscoelastic tidal heating. We compare results first from simple models using a fixed Quality factor and Love number, and then for three different viscoelastic rheologies: the Maxwell body, the Standard Anelastic Solid (SAS), and the Burgers body. The SAS and Burgers models are shown to alter the potential for extreme tidal heating by introducing the possibility of new equilibria and multiple response peaks. We find that tidal heating tends to exceed radionuclide heating at periods below 10-30 days, and exceed insolation only below 1-2 days. Extreme cases produce enough tidal heat to initiate global-scale partial melting, and an analysis of tidal limiting mechanisms such as advective cooling for earthlike planets is discussed. To explore long-term behaviors, we map equilibria points between convective heat loss and tidal heat input as functions of eccentricity. For the periods and magnitudes discussed, we show that tidal heating, if significant, is generally detrimental to the width of habitable zones.

2009-12-20

277

Tidally Heated Terrestrial Exoplanets: Viscoelastic Response Models  

CERN Document Server

Tidal friction in exoplanet systems, driven by orbits that allow for durable nonzero eccentricities at short heliocentric periods, can generate internal heating far in excess of the conditions observed in our own solar system. Secular perturbations or a notional 2:1 resonance between a Hot Earth and Hot Jupiter can be used as a baseline to consider the thermal evolution of convecting bodies subject to strong viscoelastic tidal heating. We compare results first from simple models using a fixed Quality factor and Love number, and then for three different viscoelastic rheologies: the Maxwell body, the Standard Anelastic Solid, and the Burgers body. The SAS and Burgers models are shown to alter the potential for extreme tidal heating by introducing the possibility of new equilibria and multiple response peaks. We find that tidal heating tends to exceed radionuclide heating at periods below 10-30 days, and exceed insolation only below 1-2 days. Extreme cases produce enough tidal heat to initiate global-scale parti...

Henning, Wade G; Sasselov, Dimitar D; 10.1088/0004-637X/707/2/1000

2009-01-01

278

Asymmetric Transit Curves as Indication of Orbital Obliquity: Clues from the Brown Dwarf Companion in KOI-13  

Science.gov (United States)

Exoplanets orbiting rapidly rotating stars may have unusual light curve shapes. These objects transit across an oblate disk with non-isotropic surface brightness, caused by the gravitational darkening. If such asymmetries are measured, one can infer the orbital obliquity of the exoplanet and the gravity darkened star, even without the analysis of the Rossiter-McLaughlin effect or interferometry. Here we introduce KOI-13 as the first example of a transiting system with a gravity darkened star.

Szabó, G. M.; Szabó, R.; Benkö, J. M.; Lehmann, H.; Mezö, G.; Simon, A. E.; Kövári, Z.; Hodosán, G.; Regály, Z.; Kiss, L. L.

2012-04-01

279

A SEARCH FOR ADDITIONAL PLANETS IN THE NASA EPOXI OBSERVATIONS OF THE EXOPLANET SYSTEM GJ 436  

International Nuclear Information System (INIS)

[en] We present time series photometry of the M dwarf transiting exoplanet system GJ 436 obtained with the Extrasolar Planet Observation and Characterization (EPOCh) 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 1.5 R+ interior to GJ 436b with 95% confidence and larger than 1.25 R+ with 80% 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. However, if such a planet were to transit, we would rule out planets larger than 2.0 R+ with orbital periods less than 8.5 days with 95% confidence. We also place dynamical constraints on additional bodies in the GJ 436 system, independent of radial velocity measurements. Our analysis should serve as a useful guide for similar analyses of transiting exoplanets for which radial velocity measurements are not available, such as those discovered by the Kepler mission. From the lack of observed secular perturbations, we set upper limits on the mass of a second planet as small as 10 M+ in coplanar orbits and 1 M+ in non-coplanar orbits close to GJ 436b. We present refined estimates of the system parameters for GJ 436. We find P = 2.64389579 ± 0.00000080 d, R* = 0.437 ± 0.016 Rsun, and Rp = 3.880 ± 0.147 R+. We also report a sinusoidal modulation in the GJ 436 light curve that we attribute to star spots. This signal is best fit by a period of 9.01 days, although the duration of the EPOCh observations may not have been long enough to resolve the full rotation period of the star.

2010-06-20

280

Validation of Kepler Objects of Interest Stellar Parameters And Eccentricity Distribution from Observed Transit Durations  

CERN Multimedia

The recent announcement of 2300+ candidate transiting exoplanets (KOIs) orbiting ~1800 host stars discovered with the Kepler mission enables a plethora of ensemble analysis of the architecture and properties of exoplanetary systems. We use the transit durations to probe the ensemble validity of stellar parameters for Kepler candidate host stars. Our analysis shows that the new stellar parameters are improved over the second release of KOIs. However, a systematic over-estimate of the ensemble K&M dwarf radii remains, which affects the KOI exoplanet radii inferred from transit depths. We also compare the distribution of observed transit durations to a modeled distribution of transit durations derived from the known eccentricity distribution of radial velocity (RV) discovered exoplanets. In agreement with previous work, the transit durations modeled from the RV eccentricity distribution are well described by a normal distribution. However, we find that the Kepler and RV distributions differ at a statisticall...

Plavchan, Peter; Currie, Thayne

2012-01-01

 
 
 
 
281

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

282

Lack of Transit Timing Variations of Ogle-Tr-111b: A Re-Analysis with Six New Epochs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We present six new transits of the exoplanet OGLE-TR-111b observed with the Magellan Telescopes in Chile between 2008 April and 2009 March. We combine these new transits with five previously published transit epochs for this planet between 2005 and 2006 to extend the analysis of transit timing varia...

Adams, Elisabeth Rose; Seager, Sara; Osip, D.J.; López-Morales, Mercedes; Elliot, James L.

283

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

284

Spin-Orbit Alignment for the Eccentric Exoplanet HD 147506b  

CERN Multimedia

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

285

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

286

Stellar characterization of CoRoT/Exoplanet fields with MATISSE  

CERN Multimedia

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

287

Eleven Exoplanet Host Star Angular Diameters from the CHARA Array  

CERN Document Server

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 towards 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.

Baines, Ellyn K; Brummelaar, Theo A ten; Sturmann, J; Sturmann, L; Turner, Nils H; Ridgway, Stephen T

2009-01-01

288

Detecting Exoplanets by Gravitational Microlensing using a Small Telescope  

CERN Multimedia

Gravitational microlensing is a new technique that allows low-mass exoplanets to be detected at large distances of ~7kpc. This paper briefly outlines the principles of the method and describes the observational techniques. It shows that small (e.g. 0.35m) telescopes with a CCD camera can make unexpectedly useful observations of these events.

Christie, G W

2006-01-01

289

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

290

A massive exoplanet candidate around KOI-13: independent confirmation by ellipsoidal variations  

Science.gov (United States)

We present an analysis of the KOI-13.01 candidate exoplanet system included in the 2011 September Kepler data release. The host star is a known and relatively bright (mKP= 9.95) visual binary with a separation significantly smaller (0.8 arcsec) than the size of a Kepler pixel (4 arcsec pixel-1). The Kepler light curve shows both primary and secondary eclipses, as well as significant out-of-eclipse light-curve variations. We confirm that the transit occurs round the brighter of the two stars. We model the relative contributions from (i) thermal emission from the companion, (ii) planetary reflected light, (iii) Doppler beaming and (iv) ellipsoidal variations in the host star arising from the tidal distortion of the host star by its companion. Our analysis, based on the light curve alone, enables us to constrain the mass of the KOI-13.01 companion to be MC= 8.3 ± 1.25 MJ and thus demonstrates that the transiting companion is a planet (rather than a brown dwarf which was recently proposed by Szabo). The high temperature of the host star (spectral type A5-7V, Teff= 8511-8020 K), combined with the proximity of its companion KOI-13.01, may make it one of the hottest exoplanets known, with a detectable thermal contribution to the light curve even in the Kepler optical passband. However, the single passband of the Kepler light curve does not enable us to unambiguously distinguish between the thermal and reflected components of the planetary emission. Infrared observations may help to break the degeneracy, while radial-velocity follow-up with ?˜ 100 m s-1 precision should confirm the mass of the planet.

Mislis, D.; Hodgkin, S.

2012-05-01

291

TWO NEARBY SUB-EARTH-SIZED EXOPLANET CANDIDATES IN THE GJ 436 SYSTEM  

International Nuclear Information System (INIS)

We report the detection of UCF-1.01, a strong exoplanet candidate with a radius 0.66 ± 0.04 times that of Earth (R?). This sub-Earth-sized planet transits the nearby M-dwarf star GJ 436 with a period of 1.365862 ± 8 × 10–6 days. We also report evidence of a 0.65 ± 0.06 R? exoplanet candidate (labeled UCF-1.02) orbiting the same star with an undetermined period. Using the Spitzer Space Telescope, we measure the dimming of light as the planets pass in front of their parent star to assess their sizes and orbital parameters. If confirmed today, UCF-1.01 and UCF-1.02 would be designated GJ 436c and GJ 436d, respectively, and would be part of the first multiple-transiting-planet system outside of the Kepler field. Assuming Earth-like densities of 5.515 g cm–3, we predict both candidates to have similar masses (?0.28 Earth-masses, M?, 2.6 Mars-masses) and surface gravities of ?0.65 g (where g is the gravity on Earth). UCF-1.01's equilibrium temperature (Teq, where emitted and absorbed radiation balance for an equivalent blackbody) is 860 K, making the planet unlikely to harbor life as on Earth. Its weak gravitational field and close proximity to its host star imply that UCF-1.01 is unlikely to have retained its original atmosphere; however, a transient atmosphere is possible if recent impacts or tidal heating were to supply volatiles to the surface. We also present additional observations of GJ 436b during secondary eclipse. The 3.6 ?m light curve shows indications of stellar activity, making a reliable secondary eclipse measurement impossible. A second non-detection at 4.5 ?m supports our previous work in which we find a methane-deficient and carbon monoxide-rich dayside atmosphere.

1900-01-00

292

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

293

Habitable Zone Lifetimes of Exoplanets around Main Sequence Stars.  

UK PubMed Central (United Kingdom)

Abstract The potential habitability of newly discovered exoplanets is initially assessed by determining whether their orbits fall within the circumstellar habitable zone of their star. However, the habitable zone (HZ) is not static in time or space, and its boundaries migrate outward at a rate proportional to the increase in luminosity of a star undergoing stellar evolution, possibly including or excluding planets over the course of the star's main sequence lifetime. We describe the time that a planet spends within the HZ as its "habitable zone lifetime." The HZ lifetime of a planet has strong astrobiological implications and is especially important when considering the evolution of complex life, which is likely to require a longer residence time within the HZ. Here, we present results from a simple model built to investigate the evolution of the "classic" HZ over time, while also providing estimates for the evolution of stellar luminosity over time in order to develop a "hybrid" HZ model. These models return estimates for the HZ lifetimes of Earth and 7 confirmed HZ exoplanets and 27 unconfirmed Kepler candidates. The HZ lifetime for Earth ranges between 6.29 and 7.79×10(9) years (Gyr). The 7 exoplanets fall in a range between ?1 and 54.72 Gyr, while the 27 Kepler candidate planets' HZ lifetimes range between 0.43 and 18.8 Gyr. Our results show that exoplanet HD 85512b is no longer within the HZ, assuming it has an Earth analog atmosphere. The HZ lifetime should be considered in future models of planetary habitability as setting an upper limit on the lifetime of any potential exoplanetary biosphere, and also for identifying planets of high astrobiological potential for continued observational or modeling campaigns. Key Words: Exoplanet habitability metrics-Continuously habitable zone-Stellar evolution-Planetary habitability. Astrobiology 13, 833-849.

Rushby AJ; Claire MW; Osborn H; Watson AJ

2013-09-01

294

System Geometries and Transit / Eclipse Probabilities  

CERN Multimedia

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

295

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).

von Braun K.; Kane S. R.; Mahadevan S.; Laughlin G.; Howard A.; Ciardi D. R.

2011-01-01

296

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.

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

2011-01-01

297

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

298

Transmission Spectroscopy of Exoplanet XO-2b Observed with Hubble Space Telescope NICMOS  

Science.gov (United States)

Spectroscopy during planetary transits is a powerful tool to probe exoplanet atmospheres. We present the near-infrared transit spectroscopy of XO-2b obtained with Hubble Space Telescope 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 three visits have an 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 that extracting planetary spectra is at the limit of NICMOS's capability. We derive a spectrum for the planet XO-2b using the companion star as a reference. The derived spectrum can be represented by a theoretical model including atmospheric water vapor or by a flat spectrum model. We derive a 3? upper limit of 1570 ppm on the presence of water vapor absorption in the atmosphere of XO-2b. In the Appendix, we perform a similar analysis for the gas giant planet XO-1b.

Crouzet, N.; McCullough, P. R.; Burke, C.; Long, D.

2012-12-01

299

Transmission Spectroscopy of Exoplanet XO-2b Observed with HST NICMOS  

Science.gov (United States)

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 that extracting planetary spectra is at the limit of NICMOS' capability. We derive a spectrum for the planet XO-2b using the companion star as a reference. The derived spectrum can be represented by a theoretical model including atmospheric water vapor, or by a flat spectrum model. We derive a 3-sigma upper limit of 1570 ppm on the presence of water vapor absorption in the atmosphere of XO-2b. We also perform a similar analysis for the gas giant planet XO-1b.

Crouzet, Nicolas; McCullough, P. R.; Burke, C. J.; Long, D.

2013-01-01

300

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

CERN Multimedia

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

 
 
 
 
301

Relationship between Luminosity, Irradiance and Temperature of star on the orbital parameters of exoplanets  

Directory of Open Access Journals (Sweden)

Full Text Available For 759 exoplanets detected by radial velocities method we found that distances of exoplanets from central star comply in general Schmidt law and these distances depend on the stellar surface temperature. Every stellar spectral class has a little different distribution. The Luminosity and the Irradiance has not effect on the distribution of distances of exoplanets. We have found the new formulas for calculation of effective temperature of exoplanets for spectral classes F, G, and K. These new formulas we can use for future calculation of habitable planets.

Pavel Pintr

2013-01-01

302

On the existence of energetic atoms in the upper atmosphere of exoplanet HD209458b  

CERN Document Server

Stellar irradiation and particles forcing strongly affect the immediate environment of extrasolar giant planets orbiting near their parent stars. Here, we use Far Ultraviolet (FUV) emission spectra from HD209458 in the wavelength range (1180-1710)A to bring new insight to the composition and energetic processes in play in the gas nebula around the transiting planetary companion. In that frame, we consider up-to-date atmospheric models of the giant exoplanet where we implement non-thermal line broadening to simulate the impact on the transit absorption of superthermal atoms (HI, OI, and CII) populating the upper layers of the nebula. Our sensitivity study shows that for all existing models, a significant line broadening is required for OI and probably for CII lines in order to fit the observed transit absorptions. In that frame, we show that OI and CII are preferentially heated compared to the background gas with effective temperatures as large as T_{OI}/T_B~10 for OI and T_{CII}/T_B~5 for CII. By contrast, th...

Ben-Jaffel, Lotfi

2009-01-01

303

The thermal emission of the exoplanets WASP-1b and WASP-2b  

CERN Document Server

We present a comparative study of the thermal emission of the transiting exoplanets WASP-1b and WASP-2b using the Spitzer Space Telescope. The two planets have very similar masses but suffer different levels of irradiation and are predicted to fall either side of a sharp transition between planets with and without hot stratospheres. WASP-1b is one of the most highly irradiated planets studied to date. We measure planet/star contrast ratios in all four of the IRAC bands for both planets (3.6-8.0um), and our results indicate the presence of a strong temperature inversion in the atmosphere of WASP-1b, particularly apparent at 8um, and no inversion in WASP-2b. In both cases the measured eclipse depths favor models in which incident energy is not redistributed efficiently from the day side to the night side of the planet. We fit the Spitzer light curves simultaneously with the best available radial velocity curves and transit photometry in order to provide updated measurements of system parameters. We do not find ...

Wheatley, Peter J; Harrington, Joseph; Fortney, Jonathan J; Simpson, James M; Anderson, David R; Smith, Alexis M S; Aigrain, Suzanne; Clarkson, William I; Gillon, Michael; Haswell, Carole A; Hebb, Leslie; Hébrard, Guillaume; Hellier, Coel; Hodgkin, Simon T; Horne, Keith D; Kane, Stephen R; Maxted, Pierre F L; Norton, Andrew J; Pollacco, Don L; Pont, Frederic; Skillen, Ian; Smalley, Barry; Street, Rachel A; Udry, Stephane; West, Richard G; Wilson, David M

2010-01-01

304

The fate of moons of close-in giant exoplanets  

CERN Multimedia

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 towards 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 star 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.

Namouni, Fathi

2010-01-01

305

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

306

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

307

Two Suns in The Sky: Stellar Multiplicity in Exoplanet Systems  

CERN Document Server

We present results of a reconnaissance for stellar companions to all 131 radial-velocity-detected candidate extrasolar planetary systems known as of July 1, 2005. CPM companions were investigated using the multi-epoch DSS images, and confirmed by matching the trigonometric parallax distances of the primaries to companion distances estimated photometrically. We also attempt to confirm or refute companions listed in the Washington Double Star Catalog, the Catalogs of Nearby Stars, in Hipparcos results, and in Duquennoy & Mayor (1991). Our findings indicate that a lower limit of 30 (23%) of the 131 exoplanet systems have stellar companions. We report new stellar companions to HD 38529 and HD 188015, and a new candidate companion to HD 169830. We confirm many previously reported stellar companions, including six stars in five systems that are recognized for the first time as companions to exoplanet hosts. We have found evidence that 20 entries in the Washington Double Star Catalog are not gravitationally boun...

Raghavan, D; Hambly, N C; Henry, T J; Jao, W C; Mason, B D; Subasavage, J P; Beaulieu, Thom D.; Hambly, Nigel C.; Henry, Todd J.; Jao, Wei-Chun; Mason, Brian D.; Raghavan, Deepak; Subasavage, John P.

2006-01-01

308

Flux and polarization signals of spatially inhomogeneous gaseous exoplanets  

CERN Multimedia

We present numerically calculated, disk--integrated, spectropolarimetric signals of starlight that is reflected by vertically and horizontally inhomogeneous gaseous exoplanets. We include various spatial features that are present on Solar System's gaseous planets: belts and zones, cyclonic spots, and polar hazes, to test whether such features leave traces in the disk--integrated flux and polarization signals. Broadband flux and polarization signals of starlight that is reflected by gaseous exoplanets are calculated using an efficient, adding--doubling radiative transfer code, that fully includes single and multiple scattering and polarization. The planetary model atmospheres are vertically inhomogeneous and can be horizontally inhomogeneous, and contain gas molecules and/or cloud and/or aerosol particles.

Karalidi, T; Guirado, D

2013-01-01

309

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

310

TEDI: the TripleSpec Exoplanet Discovery Instrument  

CERN Multimedia

The TEDI (TripleSpec - Exoplanet Discovery Instrument) will be the first instrument fielded specifically for finding low-mass stellar companions. The instrument is a near infra-red interferometric spectrometer used as a radial velocimeter. TEDI joins Externally Dispersed Interferometery (EDI) with an efficient, medium-resolution, near IR (0.9 - 2.4 micron) echelle spectrometer, TripleSpec, at the Palomar 200" telescope. We describe the instrument and its radial velocimetry demonstration program to observe cool stars.

Edelstein, Jerry; Erskine, David J; Feuerstein, W Michael; Marckwordt, Mario; Wishnow, Ed; Lloyd, James P; Herter, Terry; Muirhead, Phillip; Gull, George E; Henderson, Charles; Parshley, Stephen C

2007-01-01

311

The Impact of Gaia and LSST on Binaries and Exoplanets  

DEFF Research Database (Denmark)

Two upcoming large scale surveys, the ESA Gaia and LSST projects, will bring a new era in astronomy. The number of binary systems that will be observed and detected by these projects is enormous, estimations range from millions for Gaia to several tens of millions for LSST. We review some tools that should be developed and also what can be gained from these missions on the subject of binaries and exoplanets from the astrometry, photometry, radial velocity and their alert systems.

Eyer, L.; Dubath, P.

2012-01-01

312

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.

Deleuil M.; Moutou C.; Bordé P.

2011-01-01

313

Chemical Timescales in the Atmospheres of Highly Eccentric Exoplanets  

CERN Multimedia

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

314

Physical properties of 38 exoplanets (Southworth, 2012)  

Science.gov (United States)

I measure the physical properties of 38 transiting extrasolar planetary systems, bringing the total number studied within the Homogeneous Studies project to 82. Transit light curves are modelled using the jktebop code, with careful attention paid to limb darkening, orbital eccentricity and contaminating light. The physical properties of each system are obtained from the photometric parameters, published spectroscopic measurements and five sets of theoretical stellar model predictions. Statistical errors are assessed using Monte Carlo and residual permutation algorithms and propagated via a perturbation algorithm. Systematic errors are estimated from the interagreement between results calculated using five theoretical stellar models. I present the first results based on Kepler short-cadence data for Kepler-14, Kepler-15 and KOI-135. (5 data files).

Southworth, J.

2013-04-01

315

A massive exoplanet candidate around KOI-13: Independent confirmation by ellipsoidal variations  

CERN Multimedia

We present an analysis of the KOI-13.01 candidate exoplanet system included in the September 2011 Kepler data release. The host star is a known and relatively bright $(m_{\\rm KP} = 9.95)$ visual binary with a separation significantly smaller (0.8 arcsec) than the size of a Kepler pixel (4 arcsec per pixel). The Kepler light curve shows both primary and secondary eclipses, as well as significant out-of-eclipse light curve variations. We confirm that the transit occurs round the brighter of the two stars. We model the relative contributions from (i) thermal emission from the companion, (ii) planetary reflected light, (iii) Doppler beaming, and (iv) ellipsoidal variations in the host-star arising from the tidal distortion of the host star by its companion. Our analysis, based on the light curve alone, enables us to constrain the mass of the KOI-13.01 companion to be $M_{\\rm C} = 8.3 \\pm 1.25M_{\\rm J}$ and thus demonstrates that the transiting companion is a planet (rather than a brown dwarf which was recently pr...

Mislis, D

2012-01-01

316

A Model for Thermal Phase Variations of Circular and Eccentric Exoplanets  

CERN Multimedia

We present a semi-analytic model atmosphere for close-in exoplanets that captures the essential physics of phase curves: orbital and viewing geometry, advection, and re-radiation. We calibrate the model with the well-characterized transiting planet, HD 189733b, then compute light curves for seven of the most eccentric transiting planets. We present phase variations for a variety of different radiative times and wind speeds. In the limit of instant re-radiation, the light curve morphology is entirely dictated by the planet's eccentricity and argument of pericenter: the light curve maximum leads or trails the eclipse depending on whether the planet is receding from or approaching the star at superior conjunction, respectively. For a planet with non-zero radiative timescales, the phase peak occurs early for super- rotating winds, and late for sub-rotating winds. We find that for a circular orbit, the timing of the phase variation maximum with respect to superior conjunction indicates the direction of the dominan...

Cowan, Nicolas B

2010-01-01

317

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

CERN Multimedia

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

318

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

319

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 1? 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

320

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

CERN Document Server

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 1-sigma level to lie above 0.97 and 0.91, respectively. We use statistical arguments to show that coplanar orbits are favoured in both systems, and that the orientations of the planetary orb...

Chaplin, W J; Campante, T L; Handberg, R; Stello, D; Winn, J N; Basu, S; Christensen-Dalsgaard, J; Davies, G R; Metcalfe, T S; Buchhave, L A; Fischer, D A; Bedding, T R; Cochran, W D; Elsworth, Y; Gilliland, R L; Hekker, S; Huber, D; Isaacson, H; Karoff, C; Kawaler, S D; Kjeldsen, H; Latham, D W; Lund, M N; Lundkvist, M; Marcy, G W; Miglio, A; Barclay, T; Lissauer, J J

2013-01-01

 
 
 
 
321

TWO NEARBY SUB-EARTH-SIZED EXOPLANET CANDIDATES IN THE GJ 436 SYSTEM  

Energy Technology Data Exchange (ETDEWEB)

We report the detection of UCF-1.01, a strong exoplanet candidate with a radius 0.66 {+-} 0.04 times that of Earth (R{sub Circled-Plus }). This sub-Earth-sized planet transits the nearby M-dwarf star GJ 436 with a period of 1.365862 {+-} 8 Multiplication-Sign 10{sup -6} days. We also report evidence of a 0.65 {+-} 0.06 R{sub Circled-Plus} exoplanet candidate (labeled UCF-1.02) orbiting the same star with an undetermined period. Using the Spitzer Space Telescope, we measure the dimming of light as the planets pass in front of their parent star to assess their sizes and orbital parameters. If confirmed today, UCF-1.01 and UCF-1.02 would be designated GJ 436c and GJ 436d, respectively, and would be part of the first multiple-transiting-planet system outside of the Kepler field. Assuming Earth-like densities of 5.515 g cm{sup -3}, we predict both candidates to have similar masses ({approx}0.28 Earth-masses, M{sub Circled-Plus }, 2.6 Mars-masses) and surface gravities of {approx}0.65 g (where g is the gravity on Earth). UCF-1.01's equilibrium temperature (T{sub eq}, where emitted and absorbed radiation balance for an equivalent blackbody) is 860 K, making the planet unlikely to harbor life as on Earth. Its weak gravitational field and close proximity to its host star imply that UCF-1.01 is unlikely to have retained its original atmosphere; however, a transient atmosphere is possible if recent impacts or tidal heating were to supply volatiles to the surface. We also present additional observations of GJ 436b during secondary eclipse. The 3.6 {mu}m light curve shows indications of stellar activity, making a reliable secondary eclipse measurement impossible. A second non-detection at 4.5 {mu}m supports our previous work in which we find a methane-deficient and carbon monoxide-rich dayside atmosphere.

Stevenson, Kevin B.; Harrington, Joseph; Lust, Nate B.; Blecic, Jasmina; Hardy, Ryan A.; Cubillos, Patricio; Campo, Christopher J. [Planetary Sciences Group, Department of Physics, University of Central Florida Orlando, FL 32816-2385 (United States); Lewis, Nikole K. [Department of Planetary Sciences and Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Montagnier, Guillaume [European Organisation for Astronomical Research in the Southern Hemisphere (ESO), Casilla 19001, Santiago 19 (Chile); Moses, Julianne I. [Space Science Institute, 4750 Walnut St, Suite 205, Boulder, CO 80301 (United States); Visscher, Channon, E-mail: kevin218@knights.ucf.edu [Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder, CO 80302 (United States)

2012-08-10

322

IMAGES: An IMage Archive Generated for Exoplanet Surveys  

Science.gov (United States)

In the past few years, there have been a menagerie of high contrast imaging surveys which have resulted in the detection of the first brown dwarfs orbiting main sequence stars and the first directly imaged exo-planetary systems. While these discoveries are scientifically rewarding, they are rare and the majority of the images collected during these surveys show single target stars. In addition, while papers will report the number of companion non-detections down to a sensitivity limit at a specific distance from the star, the corresponding images are rarely made available to the public. To date, such data exists for over a thousand stars. Thus, we are creating IMAGES, the IMage Archive Generated for Exoplanet Searches, as a repository for high contrast images gathered from published direct imaging sub-stellar and exoplanet companion surveys. This database will serve many purposes such as 1) facilitating common proper motion confirmation for candidate companions, 2) reducing the number of redundant observations of non-detection fields, 3) providing multiplicity precursor information to better select targets for future exoplanet missions, 4) providing stringent limits on the companion fraction of stars for a wide range of age, spectral type and star formation environment, and 5) provide multi-epoch images of stars with known companions for orbital monitoring. This database will be open to the public and will be searchable and sortable and will be extremely useful for future direct imaging programs such as GPI and SPHERE as well as future planet search programs such as JWST and SIM.

Tanner, A.

2010-10-01

323

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

CERN Multimedia

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

324

Galactic cosmic ray-induced radiation dose on terrestrial exoplanets.  

Science.gov (United States)

Abstract 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. Key Words: Radiation-Radiation physics-Habitability-Habitable zone-Planetary atmospheres. Astrobiology 13, 910-919. PMID:24143867

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

2013-10-01

325

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

326

Pumping the eccentricity of exoplanets by tidal effect  

CERN Multimedia

Planets close to their host stars are believed to undergo significant tidal interactions, leading to a progressive damping of the orbital eccentricity. Here we show that, when the orbit of the planet is excited by an outer companion, tidal effects combined with gravitational interactions may give rise to a secular increasing drift on the eccentricity. As long as this secular drift counterbalances the damping effect, the eccentricity can increase to high values. This mechanism may explain why some of the moderate close-in exoplanets are observed with substantial eccentricity values.

Correia, Alexandre C M; Laskar, Jacques

2011-01-01

327

Optical Phase Curves of Kepler Exoplanets  

CERN Multimedia

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

328

Terrestrial, Habitable-Zone Exoplanet Frequency from Kepler  

CERN Multimedia

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

329

Biosignature Gases in H2-Dominated Atmospheres on Rocky Exoplanets  

CERN Document Server

(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

330

Exoplanets - search methods, discoveries, and prospects for astrobiology  

CERN Document Server

Whereas the Solar System has Mars and Europa as the best candidates for finding fossil/extant life as we know it - based on complex carbon compounds and liquid water - the 263 (non-pulsar) planetary systems around other stars as known at 15 September 2008 could between them possess many more planets where life might exist. Moreover, the number of these exoplanetary systems is growing steadily, and with this growth there is an increase in the number of planets that could bear carbon-liquid water life. In this brief review the main methods by which exoplanets are being discovered are outlined, and then the discoveries that have so far been made are presented. Habitability is then discussed, and an outline presented of how a planet could be studied from afar to determine whether it is habitable, and whether it is indeed inhabited. This review is aimed at the astrobiology community, which spans many disciplines, few of which involve exoplanets. It is therefore at a basic level and concentrates on the major topics...

Jones, Barrie W

2009-01-01

331

The mass-period distribution of close-in exoplanets  

CERN Multimedia

The lower limit to the distribution of orbital periods P for the current population of close-in exoplanets shows a distinctive discontinuity located at approximately one Jovian mass. Most smaller planets have orbital periods longer than P~2.5 days, while higher masses are found down to P~1 day. We analyze whether this observed mass-period distribution could be explained in terms of the combined effects of stellar tides and the interactions of planets with an inner cavity in the gaseous disk. We performed a series of hydrodynamical simulations of the evolution of single-planet systems in a gaseous disk with an inner cavity mimicking the inner boundary of the disk. The subsequent tidal evolution is analyzed assuming that orbital eccentricities are small and stellar tides are dominant. We find that most of the close-in exoplanet population is consistent with an inner edge of the protoplanetary disk being located at approximately P>2 days for solar-type stars, in addition to orbital decay having been caused by st...

Benitez-Llambay, P; Beauge, C

2011-01-01

332

Parametrizing the exoplanet eccentricity distribution with the Beta distribution  

Science.gov (United States)

It is suggested that the distribution of orbital eccentricities for extrasolar planets is well described by the Beta distribution. Several properties of the Beta distribution make it a powerful tool for this purpose. For example, the Beta distribution can reproduce a diverse range of probability density functions (PDFs) using just two shape parameters (a and b). We argue that this makes it ideal for serving as a parametric model in Bayesian comparative population analysis. The Beta distribution is also uniquely defined over the interval zero to unity, meaning that it can serve as a proper prior for eccentricity when analysing the observations of bound extrasolar planets. Using nested sampling, we find that the distribution of eccentricities for 396 exoplanets detected through radial velocity with high signal-to-noise is well described by a Beta distribution with parameters a = 0.867{^{+ 0.044}_{- 0.044}} and b = 3.03{^{+ 0.17}_{- 0.16}}. The Beta distribution is shown to be 3.7 times more likely to represent the underlying distribution of exoplanet eccentricities than the next best model: a Rayleigh + exponential distribution. The same data are also used in an example population comparison utilizing the Beta distribution, where we find that the short- and long-period planets are described by distinct Beta distributions at a confidence of 11.6? and display a signature consistent with the effects of tidal circularization.

Kipping, David M.

2013-07-01

333

Transit variations in WASP-3  

Science.gov (United States)

The variations in the period and duration of the transits of exoplanets allow us to obtain some of their orbital properties. Here we investigate the variations in the transit parameters of WASP-3 over a period of time that covers more than three years. Apart from providing complementary information on the geometrical configuration of the system, the investigation of transit duration (TDV) can also provide indirect evidence of the presence of additional planets. The WASP-3 system constitutes the first example for which the TDV have been tracked over a long period of time, allowing for the easier detection of secular variations of the orbital parameters. This work shows that the effects of nodal precession are clearly discernible in the TDV of WASP-3, as the theory predicts. We also confirm the presence of strong transit time (TTV) in a shorter time scale but in this case the periodicity of the signal is not so clear.

Cuesta, L.; Teresa Eibe, M.; Ullán, A.; Pérez-Verde, A.; Navas, J.

2013-05-01

334

Temperature-dependent molecular absorption cross sections for exoplanets and other atmospheres  

CERN Document Server

Exoplanets, and in particular hot ones such as hot Jupiters, require a very significant quantities of molecular spectroscopic data to model radiative transport in their atmospheres or to interpret their spectra. This data is commonly provided in the form of very extensive transition line lists. The size of these line lists is such that constructing a single model may require the consideration of several billion lines. We present a procedure to simplify this process based on the use of cross sections. Line lists for water, H$_3^+$, HCN /HNC and ammonia have been turned into cross sections on a fine enough grid to preserve their spectroscopic features. Cross sections are provided at a fixed range of temperatures and an interpolation procedure which can be used to generate cross sections at arbitrary temperatures is described. A web-based interface (www.exomol.com/xsec) has been developed to allow astronomers to download cross sections at specified temperatures and spectral resolution. Specific examples are pres...

Hill, Christian; Tennyson, Jonathan

2012-01-01

335

The Fate of Exoplanets and the Red Giant Rapid Rotator Connection  

CERN Multimedia

We have computed the fate of exoplanet companions around main sequence stars to explore the frequency of planet ingestion by their host stars during the red giant branch evolution. Using published properties of exoplanetary systems combined with stellar evolution models and Zahn's theory of tidal friction, we modeled the tidal decay of the planets' orbits as their host stars evolve. Most planets currently orbiting within 2 AU of their star are expected to be ingested by the end of their stars' red giant branch ascent. Our models confirm that many transiting planets are sufficiently close to their parent star that they will be accreted during the main sequence lifetime of the star. We also find that planet accretion may play an important role in explaining the mysterious red giant rapid rotators, although appropriate planetary systems do not seem to be plentiful enough to account for all such rapid rotators. We compare our modeled rapid rotators and surviving planetary systems to their real-life counterparts a...

Carlberg, Joleen K; Arras, Phil; Smith, Verne V; Cunha, Katia; Bizyaev, Dmitry

2010-01-01

336

The prevalence of dust on the exoplanet HD 189733b from Hubble and Spitzer observations  

CERN Document Server

The hot Jupiter HD189733b is the most extensively observed exoplanet. Its atmosphere has been detected and characterised in transmission and eclipse spectroscopy, and its phase curve measured at several wavelengths. This paper brings together the results of our campaign to obtain the complete transmission spectrum of the atmosphere of this planet from UV to IR with HST, using the STIS, ACS and WFC3 instruments. We provide a new transmission spectrum across the entire visible and infrared range. The radius ratio in each wavelength band was re-derived, where necessary, to ensure a consistent treatment of the bulk transit parameters and stellar limb-darkening. Special care was taken to correct for both occulted and unocculted star spots, and derive realistic uncertainties. The combined spectrum is very different from the predictions of cloud-free models; it is dominated by Rayleigh scattering over the whole visible and NIR range, the only detected features being narrow Na and K lines. We interpret this as the si...

Pont, F; Gibson, N P; Aigrain, S; Henry, G; Husnoo, N

2012-01-01

337

Worlds Beyond: A Strategy for the Detection and Characterization of Exoplanets  

Energy Technology Data Exchange (ETDEWEB)

This report is a comprehensive study of the search for and study of planets around other stars (exoplanets). The young but maturing field of exoplanets is perhaps one of the most compelling fields of study in science today--both because of the discoveries made to date on giant planets around other stars, and because the detection of planets just like our Earth ('Earth analogs') is at last within reach technologically. In the Report we outline the need for a vigorous research program in exoplanets to understand our place in the cosmos: whether planets like our home Earth are a common or rare outcome of cosmic evolution. The strategy we developed is intended to address the following fundamental questions, in priority order, within three distinct 5-yr long phases, over a 15 year period: (1) What are the physical characteristics of planets in the habitable zones around bright, nearby stars? (2) What is the architecture of planetary systems? (3) When, how and in what environments are planets formed? The Report recommends a two-pronged strategy for the detection and characterization of planets the size of the Earth. For stars much less massive and cooler than our Sun (M-dwarfs), existing ground-based techniques including radial velocity and transit searches, and space-based facilities both existing and under development such as Spitzer and JWST, are adequate for finding and studying planets close to the mass and size of the Earth. Conducted in parallel with the M-dwarf strategy is one for the more challenging observations of the hotter and brighter F, G, and K stars, some of which are very close in properties to our Sun, in which the frequency of Earth-sized planets is assessed with Corot and Kepler, but new space missions are required for detection and study of specific Earth-mass and Earth-sized objects. Our Task Force concludes that the development of a space-based astrometric mission, narrowly-focused to identify specific nearby stars with Earth-mass planets, followed by direct detection and study via a spaceborne coronagraph/occulter or interferometric mission, is the most robust approach to pursue. Ground and space-based microlensing programs pursued in parallel would provide complementary information on planetary system architectures on galactic scales. The program for F, G, and K stars must be preceded, at the beginning of the strategy, by broad yet detailed technical assessments to determine whether the astrometric and direct detection technologies will be ready in the time frames envisioned (the second and third 5-yr periods, respectively). Also measurement of dust around nearby candidate stars must be undertaken early to determine whether typical systems are clean enough to make direct detection feasible. Alternative strategies are discussed should problems arise in any of these areas. Finally, the Task Force lays out recommended programs in ground-based observations of larger planets, of planet-forming disks, and theoretical and laboratory studies crucial to interpreting and understanding the outcome of the planet search and characterization observations.

Lunine, J; Fischer, D; Hammel, H; Hillenbrand, L; Kasting, J; Laughlin, G; Macintosh, B; Marley, M; Melnick, G; Monet, D; Noecker, C; Peale, S; Quirrenbach, A; Seager, S; Winn, J

2008-06-02

338

CHEOPS: A transit photometry mission for ESA's small mission programme  

Directory of Open Access Journals (Sweden)

Full Text Available 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 improve the transit light curve so that the radius can be determined precisely. Because of the host stars' brightness, high precision RV measurements will be possible for all targets. All planets observed in transit by CHEOPS will be validated and their masses will be known. This will provide valuable data for constraining the mass-radius relation of exoplanets, especially in the Neptune-mass regime. During the planned 3.5 year mission, about 500 targets will be observed. There will be 20% of open time available for the community to develop new science programmes.

Broeg C.; Fortier A.; 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

339

What do stars tell us about planets? Asteroseismology of exoplanet-host stars  

CERN Multimedia

Studying the internal structure of exoplanet-host stars compared to that of similar stars without detected planets is particularly important for the understanding of planetary formation. The observed average overmetallicity of stars with planets is an interesting point in that respect. In this framework, asteroseismic studies represent an excellent tool to determine the structural differences between stars with and without detected planets. It also leads to more precise values of the stellar parameters like mass, gravity, effective temperature, than those obtained from spectroscopy alone. Interestingly enough, the detection of stellar oscillations is obtained with the same instruments as used for the discovery of exoplanets, both from the ground and from space. The time scales however are very different, as the oscillations of solar type stars have periods around five to ten minutes, while the exoplanets orbits may go from a few days up to many years. Here I discuss the asteroseismology of exoplanet-host star...

Vauclair, Sylvie

2008-01-01

340

KNOW THE STAR, KNOW THE PLANET. II. SPECKLE INTERFEROMETRY OF EXOPLANET HOST STARS  

Energy Technology Data Exchange (ETDEWEB)

A study of the host stars to exoplanets is important for understanding their environment. To that end, we report new speckle observations of a sample of exoplanet host primaries. The bright exoplanet host HD 8673 (= HIP 6702) is revealed to have a companion, although at this time we cannot definitively establish the companion as physical or optical. The observing lists for planet searches and for these observations have for the most part been pre-screened for known duplicity, so the detected binary fraction is lower than what would otherwise be expected. Therefore, a large number of double stars were observed contemporaneously for verification and quality control purposes, to ensure that the lack of detection of companions for exoplanet hosts was valid. In these additional observations, 10 pairs are resolved for the first time and 60 pairs are confirmed. These observations were obtained with the USNO speckle camera on the NOAO 4 m telescopes at both KPNO and CTIO from 2001 to 2010.

Mason, Brian D.; Hartkopf, William I. [United States Naval Observatory, Washington, DC 20392-5420 (United States); Raghavan, Deepak [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303-3083 (United States); Subasavage, John P. [Cerro Tololo Inter-American Observatory, La Serena (Chile); Roberts, Lewis C. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Turner, Nils H.; Ten Brummelaar, Theo A., E-mail: bdm@usno.navy.mil, E-mail: wih@usno.navy.mil, E-mail: raghavan@chara.gsu.edu, E-mail: jsubasavage@ctio.noao.edu, E-mail: lewis.c.roberts@jpl.nasa.gov, E-mail: nils@chara-array.org, E-mail: theo@chara-array.org [Center for High Angular Resolution Astronomy, Georgia State University, Mt. Wilson, CA 91023 (United States)

2011-11-15

 
 
 
 
341

Ground-Based Direct Detection of Exoplanets with the Gemini Planet Imager (GPI)  

CERN Multimedia

The Gemini Planet (GPI) imager is an "extreme" adaptive optics system being designed and built for the Gemini Observatory. GPI combines precise and accurate wavefront control, diffraction suppression, and a speckle-suppressing science camera with integral field and polarimetry capabilities. GPI's primary science goal is the direct detection and characterization of young, Jovian-mass exoplanets. For systems younger than 2 Gyr exoplanets more massive than 6 MJ and semimajor axes beyond 10 AU are detected with completeness greater than 50%. GPI will also discover faint debris disks, explore icy moons and minor planets in the solar system, reveal high dynamic range main-sequence binaries, and study mass loss from evolved stars. This white paper explains the role of GPI in exoplanet discovery and characterization and summarizes our recommendations to the NSF-NASA-DOE Astronomy and Astrophysics Advisory Committee ExoPlanet Task Force.

Graham, James R; Doyon, Rene; Gavel, Don; Larkin, James; Levine, Marty; Oppenheimer, Ben; Palmer, David; Saddlemyer, Les; Sivaramakrishnan, Anand; Veran, Jean-Pierre; Wallace, Kent

2007-01-01

342

NASA ExoPAG Study Analysis Group 5: Flagship Exoplanet Imaging Mission Science Goals and Requirements Report  

CERN Multimedia

The NASA Exoplanet Program Analysis Group (ExoPAG) has undertaken an effort to define mission Level 1 requirements for exoplanet direct detection missions at a range of sizes. This report outlines the science goals and requirements for the next exoplanet flagship imaging and spectroscopy mission as determined by the flagship mission Study Analysis Group (SAG) of the NASA Exoplanet Program Analysis Group (ExoPAG). We expect that these goals and requirements will be used to evaluate specific architectures for a future flagship exoplanet imaging and spectroscopy mission, and we expect this effort to serve as a guide and template for similar goals and requirements for smaller missions, an effort that we expect will begin soon. These goals and requirements were discussed, determined, and documented over a 1 year period with contributions from approximately 60 volunteer exoplanet scientists, technologists, and engineers. Numerous teleconferences, emails, and several in-person meetings were conducted to progress on ...

Greene, Tom

2013-01-01

343

A MODEL FOR THERMAL PHASE VARIATIONS OF CIRCULAR AND ECCENTRIC EXOPLANETS  

International Nuclear Information System (INIS)

We present a semi-analytic model atmosphere for close-in exoplanets that captures the essential physics of phase curves: orbital and viewing geometry, advection, and re-radiation. We calibrate the model with the well-characterized transiting planet, HD 189733b, then compute light curves for seven of the most eccentric transiting planets: Gl 436b, HAT-P-2b, HAT-P-11b, HD 17156b, HD 80606b, WASP-17b, and XO-3b. We present phase variations for a variety of different radiative times and wind speeds. In the limit of instant re-radiation, the light-curve morphology is entirely dictated by the planet's eccentricity and argument of pericenter: the light curve maximum leads or trails the eclipse depending on whether the planet is receding from or approaching the star at superior conjunction, respectively. For a planet with non-zero radiative timescales, the phase peak occurs early for super-rotating winds, and late for sub-rotating winds. We find that for a circular orbit, the timing of the phase variation maximum with respect to superior conjunction indicates the direction of the dominant winds, but cannot break the degeneracy between wind speed and radiative time. For circular planets the phase minimum occurs half an orbit away from the phase maximum-despite the fact that the coolest longitudes are always near the dawn terminator-and therefore does not convey any additional information. In general, increasing the advective frequency or the radiative time has the effect of reducing the peak-to-trough amplitude of phase variations, but there are interesting exceptions to these trends. Lastly, eccentric planets with orbital periods significantly longer than their radiative time exhibit 'ringing', whereby the hot spot generated at periastron rotates in and out of view. The existence of ringing makes it possible to directly measure the wind speed (the frequency of the ringing) and the radiative time constant (the damping of the ringing).

2011-01-10

344

HAT-P-30b: A TRANSITING HOT JUPITER ON A HIGHLY OBLIQUE ORBIT  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report the discovery of HAT-P-30b, a transiting exoplanet orbiting the V = 10.419 dwarf star GSC 0208-00722. The planet has a period P = 2.810595 [plus-minus] 0.000005 days, transit epoch T[subscript c] = 2455456.46561 [plus-minus] 0.00037 (BJD), and transit duration 0.0887 [plus-minus] 0.0015 d...

Johnson, John Asher; Winn, Joshua Nathan; Bakos, G. A.; Hartman, J. D.; Morton, T. D.; Torres, G.; Kovacs, Geza; Latham, D. W.

345

Diversity among other worlds: characterization of exoplanets by direct detection  

CERN Document Server

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 of a high scientific interest and a reasonable feasibility. The scientific interest lies in the fact that super-Earths share common geophysical attributes with Earths. They already begin to be detected by radial velocity (RV) and, together with giant planets, they have a larger area than Earths, making them detectable with a 1.5-2 m class telescope in reflected light. We propose such a (space) telescope be a first step before large direct imaging missions.

Schneider, J; Aylward, A; Baudoz, P; Beuzit, J L; Brown, R; Cho, J; Dohlen, K; Ferrari, M; Galicher, R; Grasset, O; Grenfell, L; Guyon, O; Hough, J; Kasper, M; Keller, Ch; Longmore, A; López, B; Martin, E; Mawet, D; Ménard, F; Merin, B; Palle, E; Perrin, G; Pinfield, D; Sein, E; Shore, P; Sotin, Ch; Sozzetti, A; Stam, D; Surdej, J; Tamburini, F; Tinetti, G; Udry, S; Verinaud, C; Walker, D

2008-01-01

346

Bayesian Methods for Analysis and Adaptive Scheduling of Exoplanet Observations  

CERN Multimedia

We describe work in progress by a collaboration of astronomers and statisticians developing a suite of Bayesian data analysis tools for extrasolar planet (exoplanet) detection, planetary orbit estimation, and adaptive scheduling of observations. Our work addresses analysis of stellar reflex motion data, where a planet is detected by observing the "wobble" of its host star as it responds to the gravitational tug of the orbiting planet. Newtonian mechanics specifies an analytical model for the resulting time series, but it is strongly nonlinear, yielding complex, multimodal likelihood functions; it is even more complex when multiple planets are present. The parameter spaces range in size from few-dimensional to dozens of dimensions, depending on the number of planets in the system, and the type of motion measured (line-of-sight velocity, or position on the sky). Since orbits are periodic, Bayesian generalizations of periodogram methods facilitate the analysis. This relies on the model being linearly separable, ...

Loredo, Thomas J; Chernoff, David F; Clyde, Merlise A; Liu, Bin

2011-01-01

347

International Year of Astronomy Invited Review on Exoplanets  

CERN Multimedia

Just fourteen years ago the Solar System represented the only known planetary system in the Galaxy, and conceptions of planet formation were shaped by this sample of one. Since then, 320 planets have been discovered orbiting 276 individual stars. This large and growing ensemble of exoplanets has informed theories of planet formation, placed the Solar System in a broader context, and revealed many surprises along the way. In this review I provide an overview of what has been learned from studies of the occurrence, orbits and physical structures of planets. After taking a look back at how far the field has advanced, I will discuss some of the future directions of exoplanetary science, with an eye toward the detection and characterization of Earth-like planets around other stars.

Johnson, John A

2009-01-01

348

Connecting planets around horizontal branch stars with known exoplanets  

CERN Multimedia

We study the distribution of exoplanets around main sequence (MS) stars and apply our results to the binary model for the formation of extreme horizontal branch (EHB; sdO; sdB; hot subdwarfs) stars. We conclude that sdB (EHB) stars are prime targets for planets search. We reach this conclusion by noticing that the bimodal distribution of planets around MS stars with respect to the parameter Mp*a^2, is most prominent for MS stars in the mass range 1Mo1AU. Also, if a planet or more are observed at a>1AU, it is possible that a massive planet did survive the common envelope phase, and it is orbiting the EHB with an orbital period of hours do days.

Bear, Ealeal

2010-01-01

349

PTPS Candidate Exoplanet Host Star Radii Determination with CHARA Array  

CERN Multimedia

We propose to measure the radii of the Penn State - Torun Planet Search (PTPS) exoplanet host star candidates using the CHARA Array. Stellar radii estimated from spectroscopic analysis are usually inaccurate due to indirect nature of the method and strong evolutionary model dependency. Also the so-called degeneracy of stellar evolutionary tracks due to convergence of many tracks in the giant branch decreases the precision of such estimates. However, the radius of a star is a critical parameter for the calculation of stellar luminosity and mass, which are often not well known especially for giants. With well determined effective temperature (from spectroscopy) and radius the luminosity may be calculated precisely. In turn also stellar mass may be estimated much more precisely. Therefore, direct radii measurements increase precision in the determination of planetary candidates masses and the surface temperatures of the planets.

Zielinski, Pawel; Baines, Ellyn; Niedzielski, Andrzej; Wolszczan, Aleksander

2012-01-01

350

Precision Near-Infrared Radial Velocity Instrumentation and Exoplanet Survey  

Science.gov (United States)

We have built and commissioned a gas absorption cell and non-circular core fiber scrambler for precision spectroscopic radial velocity measurements in the near-infrared. We are currently carrying out a pilot survey with the gas cell and the CSHELL spectrograph at the NASA InfraRed Telescope Facility (IRTF) to detect exoplanets around low mass and young stars. We discuss the current status of our survey, with the aim of photon-noise limited radial velocity precision. For adequately bright targets, we are able to probe a noise floor of ~7 m/s with the gas cell with CSHELL at cassegrain focus. Our results demonstrate the feasibility of applying these calibration and illumination stabilization techniques to the next generation of near-infrared spectrographs such as iSHELL on IRTF and an upgraded NIRSPEC at Keck.

Plavchan, Peter; Anglada-Escud?, G.; White, R. J.; Beichman, C. A.; Brinkworth, C.; Fitzgerald, M. P.; McLean, I. S.; Johnson, J. A.; Gao, P.; Davison, C.; Bottom, M.; Ciardi, D.; Wallace, J. K.; Mennesson, B.; von Braun, K.; Vasisht, G.; Prato, L. A.; Kane, S. R.; Tanner, A. M.

2013-01-01

351

Lithium abundances in exoplanet-host stars : modelling  

CERN Document Server

Aims. Exoplanet-host stars (EHS) are known to present superficial chemical abundances different from those of stars without any detected planet (NEHS). EHS are, on the average, overmetallic compared to the Sun. The observations also show that, for cool stars, lithium is more depleted in EHS than in NEHS. The aim of this paper is to obtain constraints on possible models able to explain this difference, in the framework of overmetallic models compared to models with solar abundances. Methods. We have computed main sequence stellar models with various masses and metallicities. The results show different behaviour for the lithium destruction according to those parameters. We compare these results to the spectroscopic observations of lithium. Results. Our models show that the observed lithium differences between EHS and NEHS are not directly due to the overmetallicity of the EHS: some extra mixing is needed below the convective zones. We discuss possible explanations for the needed extra mixing, in particular an i...

Castro, M; Richard, O; Santos, N C

2008-01-01

352

The Hot and Energetic Universe: Solar system and exoplanets  

CERN Document Server

The high resolution non-dispersive spectroscopy and unprecedented sensitivity of Athena+ will revolutionize solar system observing: the origin of the ions producing Jupiter's X-ray aurorae via charge exchange will be conclusively established, as well as their dynamics, giving clues to their acceleration mechanisms. X-ray aurorae on Saturn will be searched for to a depth unattainable by current Earth-bound observatories. The X-ray Integral Field Unit of Athena+ will map Mars' expanding exosphere, which has a line-rich solar wind charge exchange spectrum, under differing solar wind conditions and through the seasons; relating Mars' X-ray emission to its atmospheric loss will have significant impact also on the study of exoplanet atmospheres. Spectral mapping of cometary comae, which are spectacular X-ray sources with extremely line-rich spectra, will probe solar wind composition and speed at varying distances from the Sun. Athena+ will provide unique contributions also to exoplanetary astrophysics. Athena+ will...

Branduardi-Raymont, G; Dennerl, K; Güdel, M; Holmstrom, M; Koutroumpa, D; Maggio, A; Micela, G; Pillitteri, I; Sanz-Forcada, J; Read, A; Bhardwaj, A; Ezoe, Y; Gladstone, R

2013-01-01

353

Types of gaseous envelopes of "hot Jupiter" exoplanets  

Science.gov (United States)

As a rule, the orbital velocities of "hot Jupiters," i.e., exoplanets with masses comparable to the mass of Jupiter and orbital semi-major axes less than 0.1 AU, are supersonic relative to the stellar wind, resulting in the formation of a bow shock. Gas-dynamical modeling shows that the gaseous envelopes around hot Jupiters can belong to two classes, depending on the position of the collision point. if the collision point is inside the Roche lobe of the planet, the envelopes have the almost spherical shapes of classical atmospheres, slightly distorted by the influence of the star and interactions with the stellar-wind gas; if the collision point is located outside the Roche lobe, outflows from the vicinity of the Lagrangian points L1 and L2 arise, and the envelope becomes substantially asymmetrical. The latter class of objects can also be divided into two types. If the dynamical pressure of the stellar-wind gas is high enough to stop the most powerful outflow from the vicinity of the inner Lagrangian point L1, a closed quasi-spherical envelope with a complex shape forms in the system. If the wind is unable to stop the outflow from L1, an open aspherical envelope forms. The possible existence of atmospheres of these three types is confirmed by 3D numerical modeling. Using the typical hot Jupiter HD 209458b as an example, it is shown that all three types of atmospheres could exist within the range of estimated parameters of this planet. Since different types of envelopes have different observational manifestations, determining the type of envelope in HD 209458b could apply additional constrains on the parameters of this exoplanet.

Bisikalo, D. V.; Kaigorodov, P. V.; Ionov, D. E.; Shematovich, V. I.

2013-10-01

354

Klio: A 5 micron camera for the detection of giant exoplanets  

CERN Multimedia

We plan to take advantage of the unprecedented combination of low thermal background and high resolution provided by the 6.5m MMT's adaptive secondary mirror, to target the 3-5 micron atmospheric window where giant planets are expected to be anomalously bright. We are in the process of building a 3-5 micron coronograph that is predicted to be sensitive to planets as close as 0.4 arcsec to the parent star. We expect to be able to detect giant planets down to 5 times Jupiter's mass for a 1 Gyr old system at 10 pc. We plan to carry out a survey which is complementary to the radial velocity detections of planets and constructed to characterize the prevalence and distribution of giant planets around nearby, Sun-like stars.

Freed, M; Meyer, M R; Freed, Melanie; Hinz, Philip M.; Meyer, Michael R.

2003-01-01

355

Transit spectroscopy with GTC  

Directory of Open Access Journals (Sweden)

Full Text Available Thanks to different ground-based surveys and space missions, nowadays we have a fairly large sample of discovered extra-solar planets to study and, without a doubt, this number will increase in the future. One of the most succesful techniques that allows us to prove the physical properties and atmospheric composition of these exoplanets is transmission spectroscopy. The level of precision that is require to measure these effects provides a technical challenge that is solved by using big telescopes and stable instruments to reach low noise levels. In this article, we will discuss the use of the 10m class telescope GTC to observed planetary transits in spectroscopic mode and some of the results that we are currently obtaining.

Murgas F.; Pallé E.; Cabrera-Lavers A.; Osorio M.R. Zapatero; Nortmann L.

2013-01-01

356

The New Worlds Observer: Direct Detection and Study of Exoplanets from the Habitable Zone Outward  

Science.gov (United States)

Direct detection and spectroscopic study of the planets around the nearby stars is generally recognized as a prime goal of astronomy. The New Worlds Observer mission concept is being studied as an Astrophysics Strategic Mission Concept Study for this purpose. NWO features two spacecraft: a general purpose 4m telescope that operates from the UV to the Near IR, and a starshade, a flower-shaped occulter about 50m in diameter flying in alignment about 70,000km away. Our study shows this is the most effective way to map nearby planetary systems. Images will show dust and debris down to a fraction of our zodiacal light level. Planets fainter than the Earth can be seen from the Habitable Zone outward, at distances up to 20pc. High throughput and low noise enable immediate follow-up spectroscopy of discovered planets. NWO can discover many more Earth-like planets than all competing approaches including astrometric, interferometric, and internal coronagraphic. Within hours of discovery, a high quality spectrum can determine the true nature of the exoplanet and open the search for biomarkers and life. Over half of the time will be spent with the starshade in transit to the next target. During those times the telescope will be available to for general astrophysics purposes. Operating from the ultraviolet to the near infrared, this will be a true HST follow-on. The study shows all needed technologies already exist. The cost scales primarily with telescope size. The mission is definitely within the financial and technical reach of NASA for the coming decade.

Cash, Webster C.; New Worlds Study Team

2009-01-01

357

The prevalence of dust on the exoplanet HD 189733b from Hubble and Spitzer observations  

Science.gov (United States)

The hot Jupiter HD 189733b is the most extensively observed exoplanet. Its atmosphere has been detected and characterized in transmission and eclipse spectroscopy, and its phase curve measured at several wavelengths. This paper brings together the results of our campaign to obtain the complete transmission spectrum of the atmosphere of this planet from UV to infrared with the Hubble Space Telescope, using the STIS, ACS and WFC3 instruments. We provide a new tabulation of the transmission spectrum across the entire visible and infrared range. The radius ratio in each wavelength band was re-derived, where necessary, to ensure a consistent treatment of the bulk transit parameters and stellar limb darkening. Special care was taken to correct for, and derive realistic estimates of the uncertainties due to, both occulted and unocculted star spots. The combined spectrum is very different from the predictions of cloud-free models for hot Jupiters: it is dominated by Rayleigh scattering over the whole visible and near-infrared range, the only detected features being narrow sodium and potassium lines. We interpret this as the signature of a haze of condensate grains extending over at least five scaleheights. We show that a dust-dominated atmosphere could also explain several puzzling features of the emission spectrum and phase curves, including the large amplitude of the phase curve at 3.6 ?m, the small hotspot longitude shift and the hot mid-infrared emission spectrum. We discuss possible compositions and derive some first-order estimates for the properties of the putative condensate haze/clouds. We finish by speculating that the dichotomy between the two observationally defined classes of hot Jupiter atmospheres, of which HD 189733b and HD 209458b are the prototypes, might not be whether they possess a temperature inversion, but whether they are clear or dusty. We also consider the possibility of a continuum of cloud properties between hot Jupiters, young Jupiters and L-type brown dwarfs.

Pont, F.; Sing, D. K.; Gibson, N. P.; Aigrain, S.; Henry, G.; Husnoo, N.

2013-07-01

358

KEPLER EXOPLANET CANDIDATE HOST STARS ARE PREFERENTIALLY METAL RICH  

International Nuclear Information System (INIS)

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? redder than the average color of the stars in the control sample. At the same J - H color, 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 small-radius ECs is 4? redder than the average color of the stars in the control sample. These offsets are unlikely to be caused by differential reddening, age differences between the two populations, or the presence of giant stars in the control sample. Stellar models suggest that the first color offset is due to a 0.2 dex enhancement in [Fe/H] of the giant EC host population at M* ? 1 Msun, while Sloan photometry of M 67 and NGC 6791 suggests that the second color offset is due to a similar [Fe/H] enhancement of the small-radius EC host population at M* ? 0.7 Msun. These correlations are a natural consequence of the core-accretion model of planet formation.

2011-09-10

359

Tapir: A web interface for transit/eclipse observability  

Science.gov (United States)

Tapir is a set of tools, written in Perl, that provides a web interface for showing the observability of periodic astronomical events, such as exoplanet transits or eclipsing binaries. The package provides tools for creating finding charts for each target and airmass plots for each event. The code can access target lists that are stored on-line in a Google spreadsheet or in a local text file.

Jensen, Eric

2013-06-01

360

The Value of Systems with Multiple Transiting Planets  

CERN Document Server

Among other things, studies of the formation and evolution of planetary systems currently draw on two important observational resources: the precise characterization available for planets that transit their parent stars and the frequency and nature of systems with multiple planets. Thus far, the study of transiting exoplanets has focused almost exclusively on systems with only one planet, except for considering the influence of additional planets on the transit light curve, mostly through transit timing variations (TTVs). This work considers systems where multiple planets are seen to transit the same star and concludes that such "multi-transiting" systems will be the most information-rich planetary systems besides our own solar system. Five new candidate multi-transiting systems from \\emph{Kepler} have been announced in Steffen et al. 2010, though these candidates have not yet been fully confirmed as planets. In anticipation of the likely confirmation of multi-transiting systems, we discuss the value of these...

Ragozzine, Darin

2010-01-01

 
 
 
 
361

Transit timing variation and activity in the WASP-10 planetary system  

CERN Multimedia

Transit timing analysis may be an effective method of discovering additional bodies in extrasolar systems which harbour transiting exoplanets. The deviations from the Keplerian motion, caused by mutual gravitational interactions between planets, are expected to generate transit timing variations of transiting exoplanets. In 2009 we collected 9 light curves of 8 transits of the exoplanet WASP-10b. Combining these data with published ones, we found that transit timing cannot be explained by a constant period but by a periodic variation. Simplified three-body models which reproduce the observed variations of timing residuals were identified by numerical simulations. We found that the configuration with an additional planet of mass of $\\sim$0.1 $M_{\\rm{J}}$ and orbital period of $\\sim$5.23 d, located close to the outer 5:3 mean motion resonance, is the most likely scenario. If the second planet is a transiter, the estimated flux drop will be $\\sim$0.3 per cent and can be observable with a ground-based telescope. ...

Maciejewski, G; Neuhaeuser, R; Tetzlaff, N; Niedzielski, A; Raetz, St; Chen, W P; Walter, F; Marka, C; Baar, S; Krejcova, T; Budaj, J; Krushevska, V; Tachihara, K; Takahashi, H; Mugrauer, M

2010-01-01

362

Simultaneous Exoplanet Characterization and deep wide-field imaging with a diffractive pupil telescope  

CERN Multimedia

High-precision astrometry can identify exoplanets and measure their orbits and masses, while coronagraphic imaging enables detailed characterization of their physical properties and atmospheric compositions through spectroscopy. In a previous paper, we showed that a diffractive pupil telescope (DPT) in space can enable sub-microarcsecond accuracy astrometric measurements from wide-field images by creating faint but sharp diffraction spikes around the bright target star. The DPT allows simultaneous astrometric measurement and coronagraphic imaging, and we discuss and quantify in this paper the scientific benefits of this combination for exoplanet science investigations: identification of exoplanets with increased sensitivity and robustness, and ability to measure planetary masses to high accuracy. We show how using both measurements to identify planets and measure their masses offers greater sensitivity and provides more reliable measurements than possible with separate missions, and therefore results in a lar...

Guyon, Olivier; Angel, Roger; Woolf, Neville J; Bendek, Eduardo A; Milster, Thomas D; Ammons, Stephen M; Shao, Michael; Shaklan, Stuart; Levine, Marie; Nemati, Bijan; Martinache, Frantz; Pitman, Joe; Woodruff, Robert A; Belikov, Ruslan; 10.1088/0004-637X/767/1/11

2013-01-01

363

Photochemistry in Terrestrial Exoplanet Atmospheres I: Photochemistry Model and Benchmark Cases  

CERN Multimedia

We present a comprehensive photochemistry model for exploration of the chemical composition of terrestrial exoplanet atmospheres. The photochemistry model is designed from the ground up to have the capacity to treat all types of terrestrial planet atmospheres, ranging from oxidizing through reducing, which makes the code suitable for applications for the wide range of anticipated terrestrial exoplanet compositions. The one-dimensional chemical transport model treats up to 800 chemical reactions, photochemical processes, dry and wet deposition, surface emission and thermal escape of O, H, C, N and S bearing species, as well as formation and deposition of elemental sulfur and sulfuric acid aerosols. We validate the model by computing the atmospheric composition of current Earth and Mars and find agreement with observations of major trace gases in Earth's and Mars' atmospheres. We simulate several plausible atmospheric scenarios of terrestrial exoplanets, and choose three benchmark cases for atmospheres from red...

Hu, Renyu; Bains, William

2012-01-01

364

Fundamental Parameters of the Exoplanet Host K Giant Star iota Draconis from the CHARA Array  

CERN Document Server

We measured the angular diameter of the exoplanet host star iota Dra with Georgia State University's Center for High Angular Resolution Astronomy (CHARA) Array interferometer, and, using the star's parallax and photometry from the literature, calculated its physical radius and effective temperature. We then combined our results with stellar oscillation frequencies from Zechmeister et al. (2008) and orbital elements from Kane et al. (2010) to determine the masses for the star and exoplanet. Our value for the central star's mass is 1.82 +/- 0.23 M_Sun, which means the exoplanet's minimum mass is 12.6 +/- 1.1 M_Jupiter. Using our new effective temperature, we recalculated the habitable zone for the system, though it is well outside the star-planet separation.

Baines, Ellyn K; Brummelaar, Theo A ten; Turner, Nils H; Sturmann, Judit; Sturmann, Laszlo; Goldfinger, P J; Farrington, Christopher D; Ridgway, Stephen T

2011-01-01

365

FUNDAMENTAL PARAMETERS OF THE EXOPLANET HOST K GIANT STAR {iota} DRACONIS FROM THE CHARA ARRAY  

Energy Technology Data Exchange (ETDEWEB)

We measured the angular diameter of the exoplanet host star {iota} Dra with Georgia State University's Center for High Angular Resolution Astronomy Array interferometer and, using the star's parallax and photometry from the literature, calculated its physical radius and effective temperature. We then combined our results with stellar oscillation frequencies from Zechmeister et al. and orbital elements from Kane et al. to determine the masses for the star and exoplanet. Our value for the central star's mass is 1.82 {+-} 0.23 M{sub Sun }, which means the exoplanet's minimum mass is 12.6 {+-} 1.1 M{sub Jupiter}. Using our new effective temperature, we recalculated the habitable zone for the system, though it is well outside the star-planet separation.

Baines, Ellyn K. [Remote Sensing Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); McAlister, Harold A.; Ten Brummelaar, Theo A.; Turner, Nils H.; Sturmann, Judit; Sturmann, Laszlo; Goldfinger, P. J.; Farrington, Christopher D. [Center for High Angular Resolution Astronomy, Georgia State University, P.O. Box 3969, Atlanta, GA 30302-3969 (United States); Ridgway, Stephen T., E-mail: ellyn.baines@nrl.navy.mil [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726-6732 (United States)

2011-12-20

366

Discerning Exoplanet Migration Models Using Spin-Orbit Measurements  

CERN Multimedia

We investigate the current sample of exoplanet spin-orbit measurements to determine whether a dominant planet migration channel can be identified, and at what confidence. We use the predictions of Kozai migration plus tidal friction (Fabrycky and Tremaine 2007) and planet-planet scattering (Nagasawa et al. 2008) as our misalignment models, and we allow for a fraction of intrinsically aligned systems, explainable by disk migration. Bayesian model comparison demonstrates that the current sample of 32 spin-orbit measurements strongly favors a two-mode migration scenario combining planet-planet scattering and disk migration over a single-mode Kozai migration scenario. Our analysis indicates that between 34% and 76% of close-in planets (95% confidence) migrated via planet-planet scattering. Separately analyzing the subsample of 12 stars with T_eff > 6250 K---which Winn et al. (2010) predict to be the only type of stars to maintain their primordial misalignments---we find that the data favor a single-mode scatterin...

Morton, Timothy D

2010-01-01

367

PULSE: Palomar Ultraviolet Laser for the Study of Exoplanets  

CERN Document Server

PULSE is a new concept to augment the currently operating 5.1-m Hale PALM-3000 exoplanet adaptive optics system with an ultraviolet Rayleigh laser and associated wavefront sensor. By using an ultraviolet laser to measure the high spatial and temporal order turbulence near the telescope aperture, where it dominates, one can extend the faintness limit of natural guide stars needed by PALM-3000. Initial simulations indicate that very-high infrared contrast ratios and good visible-light adaptive optics performance will be achieved by such an upgraded system on stars as faint as mV = 16-17 using an optimized low-order NGS sensor. This will enable direct imaging searches for, and subsequent characterization of, companions around cool, low-mass stars for the first time, as well as routine visible-light imaging twice as sharp as HST for fainter targets. PULSE will reuse the laser and wavefront sensor technologies developed for the automated Robo-AO laser system currently operating at the Palomar 60-inch telescope, as...

Baranec, Christoph; van Dam, Marcos; Burruss, Rick

2013-01-01

368

Parametrizing the exoplanet eccentricity distribution with the Beta distribution  

CERN Multimedia

It is suggested that the distribution of orbital eccentricities for extrasolar planets is well-described by the Beta distribution. Several properties of the Beta distribution make it a powerful tool for this purpose. For example, the Beta distribution can reproduce a diverse range of probability density functions (PDFs) using just two shape parameters (a and b). We argue that this makes it ideal for serving as a parametric model in Bayesian comparative population analysis. The Beta distribution is also uniquely defined over the interval zero to unity, meaning that it can serve as a proper prior for eccentricity when analysing the observations of bound extrasolar planets. Using nested sampling, we find that the distribution of eccentricities for 396 exoplanets detected through radial velocity with high signal-to-noise is well-described by a Beta distribution with parameters a = 0.867+/-0.044 and b = 3.03+/-0.17. The Beta distribution is shown to be 3.7 times more likely to represent the underlying distribution...

Kipping, David M

2013-01-01

369

THE SPIN EFFECT ON PLANETARY RADIAL VELOCIMETRY OF EXOPLANETS  

Energy Technology Data Exchange (ETDEWEB)

We consider the effect of planetary spin on the planetary radial velocity (PRV) in dayside spectra of exoplanets. To understand the spin effect qualitatively, we derive an analytic formula of the intensity-weighted radial velocity from the planetary surface on the following assumptions: (1) constant and solid rotation without precession, (2) stable and uniform distribution of molecules/atoms, (3) emission models from the dayside hemisphere, and (4) a circular orbit. On these assumptions, we find that the curve of the PRV is distorted by the planetary spin and this anomaly is characterized by the spin radial velocity at the equator and a projected angle on a celestial plane between the spin axis and the axis of orbital motion {lambda}{sub p} in a manner analogous to the Rossiter-McLaughlin effect. The latter can constrain the planetary obliquity. Creating mock PRV data with 3 km s{sup -1} accuracy, we demonstrate how {lambda}{sub p} and the spin radial velocity at the equator are estimated. We find that the stringent constraint of eccentricity is crucial to detect the spin effect. Though our formula is still qualitative, we conclude that the PRV in the dayside spectra will be a powerful means for constraining the planetary spin.

Kawahara, Hajime, E-mail: divrot@gmail.com [Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397 (Japan)

2012-11-20

370

MAGNETIC ACTIVITY CYCLES IN THE EXOPLANET HOST STAR {epsilon} ERIDANI  

Energy Technology Data Exchange (ETDEWEB)

The active K2 dwarf {epsilon} Eri has been extensively characterized both as a young solar analog and more recently as an exoplanet host star. As one of the nearest and brightest stars in the sky, it provides an unparalleled opportunity to constrain stellar dynamo theory beyond the Sun. We confirm and document the 3-year magnetic activity cycle in {epsilon} Eri originally reported by Hatzes and coworkers, and we examine the archival data from previous observations spanning 45 years. The data show coexisting 3-year and 13-year periods leading into a broad activity minimum that resembles a Maunder minimum-like state, followed by the resurgence of a coherent 3-year cycle. The nearly continuous activity record suggests the simultaneous operation of two stellar dynamos with cycle periods of 2.95 {+-} 0.03 years and 12.7 {+-} 0.3 years, which, by analogy with the solar case, suggests a revised identification of the dynamo mechanisms that are responsible for the so-called 'active' and 'inactive' sequences as proposed by Boehm-Vitense. Finally, based on the observed properties of {epsilon} Eri, we argue that the rotational history of the Sun is what makes it an outlier in the context of magnetic cycles observed in other stars (as also suggested by its Li depletion), and that a Jovian-mass companion cannot be the universal explanation for the solar peculiarities.

Metcalfe, T. S.; Mathur, S. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Buccino, A. P.; Mauas, P. J. D.; Petrucci, R. [Instituto de Astronomia y Fisica del Espacio (CONICET), C.C. 67 Sucursal 28, C1428EHA-Buenos Aires (Argentina); Brown, B. P. [Department of Astronomy and Center for Magnetic Self-Organization, University of Wisconsin, Madison, WI 53706-1582 (United States); Soderblom, D. R. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Henry, T. J. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302 (United States); Hall, J. C. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Basu, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)

2013-02-01

371

Magnetic Activity Cycles in the Exoplanet Host Star epsilon Eridani  

Science.gov (United States)

The active K2 dwarf epsilon Eri has been extensively characterized both as a young solar analog and more recently as an exoplanet host star. As one of the nearest and brightest stars in the sky, it provides an unparalleled opportunity to constrain stellar dynamo theory beyond the Sun. We confirm and document the 3-year magnetic activity cycle in epsilon Eri originally reported by Hatzes and coworkers, and we examine the archival data from previous observations spanning 45 years. The data show coexisting 3-year and 13-year periods leading into a broad activity minimum that resembles a Maunder minimum-like state, followed by the resurgence of a coherent 3-year cycle. The nearly continuous activity record suggests the simultaneous operation of two stellar dynamos with cycle periods of 2.95 ± 0.03 years and 12.7 ± 0.3 years, which, by analogy with the solar case, suggests a revised identification of the dynamo mechanisms that are responsible for the so-called "active" and "inactive" sequences as proposed by Böhm-Vitense. Finally, based on the observed properties of epsilon Eri, we argue that the rotational history of the Sun is what makes it an outlier in the context of magnetic cycles observed in other stars (as also suggested by its Li depletion), and that a Jovian-mass companion cannot be the universal explanation for the solar peculiarities.

Metcalfe, T. S.; Buccino, A. P.; Brown, B. P.; Mathur, S.; Soderblom, D. R.; Henry, T. J.; Mauas, P. J. D.; Petrucci, R.; Hall, J. C.; Basu, S.

2013-02-01

372

A Review of Correlated Noise in Exoplanet Light Curves  

Science.gov (United States)

A number of the occultation light curves of exoplanets exhibit time-correlated residuals (a.k.a. correlated or red noise) in their model fits. The correlated noise might arise from inaccurate models or unaccounted astrophysical or telescope systematics. A correct assessment of the correlated noise is important to determine true signal-to-noise ratios of a planet's physical parameters. Yet, there are no in-depth statistical studies in the literature for some of the techniques currently used (RMS-vs-bin size plot, prayer beads, and wavelet-based modeling). We subjected these correlated-noise assessment techniques to basic tests on synthetic data sets to characterize their features and limitations. Initial results indicate, for example, that, sometimes the RMS-vs-bin size plots present artifacts when the bin size is similar to the observation duration. Further, the prayer beads doesn't correctly increase the uncertainties to compensate for the lack of accuracy if there is correlated noise. We have applied these techniques to several Spitzer secondary-eclipse hot-Jupiter light curves and discuss their implications. This work was supported in part by NASA planetary atmospheres grant NNX13AF38G and Astrophysics Data Analysis Program NNX12AI69G.

Cubillos, Patricio; Harrington, J.; Blecic, J.; Hardy, R. A.; Hardin, M.

2013-10-01

373

On the Orbit of Exoplanet WASP-12b  

CERN Document Server

We observed two secondary eclipses of the exoplanet WASP-12b using the Infrared Array Camera on the Spitzer Space Telescope. The close proximity of WASP-12b to its G-type star results in extreme tidal forces capable of inducing apsidal precession with a period as short as a few decades. This precession would be measurable if the orbit had a significant eccentricity. The ground-based secondary eclipse phase reported by Lopez-Morales et al. (0.510 +/- 0.002) implies eccentricity at the 4.5\\sigma level, and the spectroscopic orbit of Hebb et al. has eccentricity 0.049 +/- 0.015, a 3\\sigma result, and predicts an eclipse phase of 0.509 +/- 0.007. Our eclipse phases are 0.5012 +/- 0.0006 (3.6 and 5.8 micron) and 0.5007 +/- 0.0007 (4.5 and 8.0 micron). These values are inconsistent with the ground-based data, but marginally consistent with the spectroscopic orbit. Considering the unlikely possibility that precession brought the long axis of the orbit into alignment during our observations, a model considering these...

Campo, Christopher J; Hardy, Ryan A; Stevenson, Kevin B; Nymeyer, Sarah; Ragozzine, Darin; Lust, Nate B; Anderson, David R; Collier-Cameron, Andrew; Blecic, Jasmina; Britt, Christopher B T; Bowman, William C; Wheatley, Peter J; Deming, Drake; Hebb, Leslie; Hellier, Coel; Maxted, Pierre F L; Pollaco, Don; West, Richard G

2010-01-01

374

PynPoint: An Image Processing Package for Finding Exoplanets  

CERN Document Server

We present the scientific performance results of PynPoint, our Python-based software package that uses principle component analysis to detect and estimate the flux of exoplanets in two dimensional imaging data. Recent advances in adaptive optics and imaging technology at visible and infrared wavelengths have opened the door to direct detections of planetary companions to nearby stars, but image processing techniques have yet to be optimized. We show that the performance of our approach gives a marked improvement over what is presently possible using existing methods such as LOCI. To test our approach, we use real angular differential imaging (ADI) data taken with the adaptive optics assisted high resolution near-infrared camera NACO at the VLT. These data were taken during the commissioning of the apodising phase plate (APP) coronagraph. By inserting simulated planets into these data, we test the performance of our method as a function of planet brightness for different positions on the image. We find that in...

Amara, Adam

2012-01-01

375

The Spin Effect on Planetary Radial Velocimetry of Exoplanets  

CERN Document Server

We consider the effect of planetary spin on the planetary radial velocity (PRV) in dayside spectra of exoplanets. To understand the spin effect qualitatively, we derive an analytic formula of the intensity-weighted radial velocity from planetary surface on the following assumptions: 1) constant and solid rotation without precession, 2) stable and uniform distribution of molecules/atoms, 3) emission models from dayside hemisphere, and 4) a circular orbit. On these assumptions, we find that the curve of the PRV is distorted by the planetary spin and this anomaly is characterized by spin radial velocity at equator and a projected angle on a celestial plane between the spin axis and the axis of orbital motion lambda_p in a manner analogous to the Rossiter-McLaughlin effect. The latter can constrain the planetary obliquity. Creating mock PRV data with 3 km/s accuracy, we demonstrate how lambda_p and the spin radial velocity at equator are estimated. Though our formula is still qualitative, we conclude that the PRV...

Kawahara, Hajime

2012-01-01

376

Inference of Inhomogeneous Clouds in an Exoplanet Atmosphere  

Science.gov (United States)

We present new visible and infrared observations of the hot Jupiter Kepler-7b to determine its atmospheric properties. Our analysis allows us to (1) refine Kepler-7b's relatively large geometric albedo of Ag = 0.35 ± 0.02, (2) place upper limits on Kepler-7b thermal emission that remains undetected in both Spitzer bandpasses and (3) report a westward shift in the Kepler optical phase curve. We argue that Kepler-7b's visible flux cannot be due to thermal emission or Rayleigh scattering from H2 molecules. We therefore conclude that high altitude, optically reflective clouds located west from the substellar point are present in its atmosphere. We find that a silicate-based cloud composition is a possible candidate. Kepler-7b exhibits several properties that may make it particularly amenable to cloud formation in its upper atmosphere. These include a hot deep atmosphere that avoids a cloud cold trap, very low surface gravity to suppress cloud sedimentation, and a planetary equilibrium temperature in a range that allows for silicate clouds to potentially form in the visible atmosphere probed by Kepler. Our analysis does not only present evidence of optically thick clouds on Kepler-7b but also yields the first map of clouds in an exoplanet atmosphere.

Demory, Brice-Olivier; de Wit, Julien; Lewis, Nikole; Fortney, Jonathan; Zsom, Andras; Seager, Sara; Knutson, Heather; Heng, Kevin; Madhusudhan, Nikku; Gillon, Michael; Barclay, Thomas; Desert, Jean-Michel; Parmentier, Vivien; Cowan, Nicolas B.

2013-10-01

377

Transport of Ionizing Radiation in Terrestrial-like Exoplanet Atmospheres  

CERN Multimedia

(Abridged) Propagation of ionizing radiation, as from parent star flares, supernovae, or gamma-ray bursts, is studied for a suite of simple model atmospheres of terrestrial-like exoplanets covering a large range of column densities and incident photon energies. We developed a Monte Carlo code to treat the Compton scattering and photoabsorption. Atmospheres thinner than about 100 g cm^-2 transmit a significant fraction of incident gamma-rays, but even the thinnest atmospheres are essentially opaque to X-rays below about 30 keV. For thicker atmospheres, the incident ionizing radiation is efficiently blocked, but most of the incident energy is redistributed via secondary electron excitation into diffuse UV and visible aurora-like emission, increasing the atmospheric transmission by many orders of magnitude; in some cases the transmission can be up to 10%, depending on the intervening UV opacity. For Earth, between 2 x 10^-3 and 4 x 10^-2 of the incident flux reaches the ground in the 200-320 nm range, depending ...

Smith, D S; Wheeler, J C; Smith, David S.; Scalo, John

2003-01-01

378

The Distribution of Transit Durations for Kepler Planet Candidates and Implications for their Orbital Eccentricities  

CERN Multimedia

Doppler planet searches have discovered that giant planets follow orbits with a wide range of orbital eccentricities, revolutionizing theories of planet formation. The discovery of hundreds of exoplanet candidates by NASA's Kepler mission enables astronomers to characterize the eccentricity distribution of small exoplanets. Measuring the eccentricity of individual planets is only practical in favorable cases that are amenable to complementary techniques (e.g., radial velocities, transit timing variations, occultation photometry). Yet even in the absence of individual eccentricities, it is possible to study the distribution of eccentricities based on the distribution of transit durations (relative to the maximum transit duration for a circular orbit). We analyze the transit duration distribution of Kepler planet candidates. We find that for host stars with T_eff > 5100 K we cannot invert this to infer the eccentricity distribution at this time due to uncertainties and possible systematics in the host star dens...

Moorhead, Althea V; Morehead, Robert C; Rowe, Jason; Borucki, William J; Batalha, Natalie M; Bryson, Stephen T; Caldwell, Douglas A; Fabrycky, Daniel C; Gautier, Thomas N; Koch, David G; Holman, Matthew J; Jenkins, Jon M; Li, Jie; Lissauer, Jack J; Lucas, Philip; Marcy, Geoffrey W; Quinn, Samuel N; Quintana, Elisa; Ragozzine, Darin; Shporer, Avi; Still, Martin; Torres, Guillermo

2011-01-01

379

NON-DETECTION OF PREVIOUSLY REPORTED TRANSITS OF HD 97658b WITH MOST PHOTOMETRY  

Energy Technology Data Exchange (ETDEWEB)

The radial velocity-discovered exoplanet HD 97658b was recently announced to transit, with a derived planetary radius of 2.93 {+-} 0.28 R{sub Circled-Plus }. As a transiting super-Earth orbiting a bright star, this planet would make an attractive candidate for additional observations, including studies of its atmospheric properties. We present and analyze follow-up photometric observations of the HD 97658 system acquired with the Microvariability and Oscillations of STars space telescope. Our results show no transit with the depth and ephemeris reported in the announcement paper. For the same ephemeris, we rule out transits for a planet with radius larger than 2.09 R{sub Circled-Plus }, corresponding to the reported 3{sigma} lower limit. We also report new radial velocity measurements which continue to support the existence of an exoplanet with a period of 9.5 days, and obtain improved orbital parameters.

Dragomir, Diana; Matthews, Jaymie M.; Antoci, Victoria [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T1Z1 (Canada); Howard, Andrew W.; Marcy, Geoffrey W. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Henry, Gregory W. [Center of Excellence in Information Systems, Tennessee State University, 3500 John A. Merritt Blvd., Box 9501, Nashville, TN 37209 (United States); Guenther, David B. [Department of Astronomy and Physics, St. Marys University Halifax, NS B3H 3C3 (Canada); Johnson, John A. [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Kuschnig, Rainer; Weiss, Werner W. [Universitaet Wien, Institut fuer Astronomie, Tuerkenschanzstrasse 17, A1180 Wien (Austria); Moffat, Anthony F. J. [Dept de physique, Univ de Montreal C.P. 6128, Succ. Centre-Ville, Montreal, QC H3C 3J7, and Obs. du mont Megantic (Canada); Rowe, Jason F. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Rucinski, Slavek M. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Sasselov, Dimitar, E-mail: diana@phas.ubc.ca [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-11-10

380

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

Science.gov (United States)

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. It has been claimed that the hot jupiter HAT-P-13b suddenly deviated from a linear ephemeris by ~20 min, implying that there is 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 hypothetical perturber. Based on observations collected at Asiago observatory.Photometric data is only available at CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/532/A24

Nascimbeni, V.; Piotto, G.; Bedin, L. R.; Damasso, M.; Malavolta, L.; Borsato, L.

2011-08-01

 
 
 
 
381

Non-detection of Previously Reported Transits of HD 97658b with MOST Photometry  

DEFF Research Database (Denmark)

The radial velocity-discovered exoplanet HD 97658b was recently announced to transit, with a derived planetary radius of 2.93 ± 0.28 R ?. As a transiting super-Earth orbiting a bright star, this planet would make an attractive candidate for additional observations, including studies of its atmospheric properties. We present and analyze follow-up photometric observations of the HD 97658 system acquired with the Microvariability and Oscillations of STars space telescope. Our results show no transit with the depth and ephemeris reported in the announcement paper. For the same ephemeris, we rule out transits for a planet with radius larger than 2.09 R ?, corresponding to the reported 3? lower limit. We also report new radial velocity measurements which continue to support the existence of an exoplanet with a period of 9.5 days, and obtain improved orbital parameters.

Dragomir, Diana; Matthews, Jaymie M.

2012-01-01

382

Transit Timing Variation studies of Kepler exoplanetary systems  

Science.gov (United States)

When multiple planets are present in a transiting exoplanetary system, dynamical interactions among the planets will cause variations in the interval between successive planetary transits. These transit timing variations (TTVs) are can be used to characterize the orbits and masses of the different interacting bodies. I present the results of ongoing investigations of the TTV signal in exoplanet systems from the Kepler mission. For some systems, TTVs may be used to identify nontransiting planets, to confirm the planet-nature of candidates, and to identify or constrain important orbital parameters.

Steffen, Jason H.; Kepler Science Team

2010-10-01

383

USING STELLAR DENSITIES TO EVALUATE TRANSITING EXOPLANETARY CANDIDATES  

International Nuclear Information System (INIS)

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 which accurate stellar densities can be extracted without additional observations.

2011-01-10

384

An extrasolar planet that transits the disk of its parent star.  

UK PubMed Central (United Kingdom)

Planets orbiting other stars could in principle be found through the periodic dimming of starlight as a planet moves across--or 'transits'--the line of sight between the observer and the star. Depending on the size of the planet relative to the star, the dimming could reach a few per cent of the apparent brightness of the star. Despite many searches, no transiting planet has been discovered in this way; the one known transiting planet--HD209458b--was first discovered using precise measurements of the parent star's radial velocity and only subsequently detected photometrically. Here we report radial velocity measurements of the star OGLE-TR-56, which was previously found to exhibit a 1.2-day transit-like light curve in a survey looking for gravitational microlensing events. The velocity changes that we detect correlate with the light curve, from which we conclude that they are probably induced by an object of around 0.9 Jupiter masses in an orbit only 0.023 au from its star. We estimate the planetary radius to be around 1.3 Jupiter radii and its density to be about 0.5 g x cm(-3). This object is hotter than any known planet (approximately 1,900 K), but is still stable against long-term evaporation or tidal disruption.

Konacki M; Torres G; Jha S; Sasselov DD

2003-01-01

385

PLANET HUNTERS: A TRANSITING CIRCUMBINARY PLANET IN A QUADRUPLE STAR SYSTEM  

International Nuclear Information System (INIS)

[en] We report the discovery and confirmation of a transiting circumbinary planet (PH1b) around KIC 4862625, an eclipsing binary in the Kepler field. The planet was discovered by volunteers searching the first six Quarters of publicly available Kepler data as part of the Planet Hunters citizen science project. Transits of the planet across the larger and brighter of the eclipsing stars are detectable by visual inspection every ?137 days, with seven transits identified in Quarters 1-11. The physical and orbital parameters of both the host stars and planet were obtained via a photometric-dynamical model, simultaneously fitting both the measured radial velocities and the Kepler light curve of KIC 4862625. The 6.18 ± 0.17 R? planet orbits outside the 20 day orbit of an eclipsing binary consisting of an F dwarf (1.734 ± 0.044 R?, 1.528 ± 0.087 M?) and M dwarf (0.378 ± 0.023 R?, 0.408 ± 0.024 M?). For the planet, we find an upper mass limit of 169 M? (0.531 Jupiter masses) at the 99.7% confidence level. With a radius and mass less than that of Jupiter, PH1b is well within the planetary regime. Outside the planet's orbit, at ?1000 AU, a previously unknown visual binary has been identified that is likely bound to the planetary system, making this the first known case of a quadruple star system with a transiting planet.

2013-05-10

386

A Bayesian Surrogate Model for Rapid Time Series Analysis and Application to Exoplanet Observations  

CERN Document Server

We present a Bayesian surrogate model for the analysis of periodic or quasi-periodic time series data. We describe a computationally efficient implementation that enables Bayesian model comparison. We apply this model to simulated and real exoplanet observations. We discuss the results and demonstrate some of the challenges for applying our surrogate model to realistic exoplanet data sets. In particular, we find that analyses of real world data should pay careful attention to the effects of uneven spacing of observations and the choice of prior for the "jitter" parameter.

Ford, Eric B; Veras, Dimitri

2011-01-01

387

Hydrogen-loosing planets in transition discs around young protostars  

CERN Multimedia

We point out that protoplanets created in the framework of the Tidal Downsizing (TD) theory for planet formation play a very important role for the evolution of accretion discs hosting them. Since all TD protoplanets are initially as massive as $\\sim 10$ Jupiter masses, they are able to open very deep gaps in their discs, and even completely isolate the inner disc flows from the outer ones. Furthermore, in contrast to other planet formation theories, TD protoplanets are mass donors for their protostars. One potentially observable signature of planets being devoured by their protostars are FU Ori like outbursts, and episodic protostar accretion more generally, as discussed by a number of authors recently. Here we explore another observational implication of TD hypothesis: dust poor inner accretion flows, which we believe may be relevant to some of the observed mm-bright transitional discs around protostars. In our model, a massive protoplanet interrupts the flow of the outer dust-rich disc on its protostar, an...

Nayakshin, Sergei

2013-01-01

388

The Potential Feasibility of Chlorinic Photosynthesis on Exoplanets  

Science.gov (United States)

The modern search for life-bearing exoplanets emphasizes the potential detection of O2 and O3 absorption spectra in exoplanetary atmospheres as ideal signatures of biology. However, oxygenic photosynthesis may not arise ubiquitously in exoplanetary biospheres. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This paper defines chlorinic photosynthesis (CPS) as biologically mediated photolytic oxidation of aqueous Cl- to form halocarbon or dihalogen products, coupled with CO2 assimilation. This hypothetical metabolism appears to be feasible energetically, physically, and geochemically, and could potentially develop under conditions that approximate the terrestrial Archean. It is hypothesized that an exoplanetary biosphere in which chlorinic photosynthesis dominates primary production would tend to evolve a strongly oxidizing, halogen-enriched atmosphere over geologic time. It is recommended that astronomical observations of exoplanetary outgoing thermal emission spectra consider signs of halogenated chemical species as likely indicators of the presence of a chlorinic biosphere. Planets that favor the evolution of CPS would probably receive equivalent or greater surface UV flux than is produced by the Sun, which would promote stronger abiotic UV photolysis of aqueous halides than occurred during Earth's Archean era and impose stronger evolutionary selection pressures on endemic life to accommodate and utilize halogenated compounds. Ocean-bearing planets of stars with metallicities equivalent to, or greater than, the Sun should especially favor the evolution of chlorinic biospheres because of the higher relative seawater abundances of Cl, Br, and I such planets would tend to host. Directed searches for chlorinic biospheres should probably focus on G0-G2, F, and A spectral class stars that have bulk metallicities of +0.0 Dex or greater.

Haas, Johnson R.

2010-11-01

389

The potential feasibility of chlorinic photosynthesis on exoplanets.  

UK PubMed Central (United Kingdom)

The modern search for life-bearing exoplanets emphasizes the potential detection of O(2) and O(3) absorption spectra in exoplanetary atmospheres as ideal signatures of biology. However, oxygenic photosynthesis may not arise ubiquitously in exoplanetary biospheres. Alternative evolutionary paths may yield planetary atmospheres tinted with the waste products of other dominant metabolisms, including potentially exotic biochemistries. This paper defines chlorinic photosynthesis (CPS) as biologically mediated photolytic oxidation of aqueous Cl(-) to form halocarbon or dihalogen products, coupled with CO(2) assimilation. This hypothetical metabolism appears to be feasible energetically, physically, and geochemically, and could potentially develop under conditions that approximate the terrestrial Archean. It is hypothesized that an exoplanetary biosphere in which chlorinic photosynthesis dominates primary production would tend to evolve a strongly oxidizing, halogen-enriched atmosphere over geologic time. It is recommended that astronomical observations of exoplanetary outgoing thermal emission spectra consider signs of halogenated chemical species as likely indicators of the presence of a chlorinic biosphere. Planets that favor the evolution of CPS would probably receive equivalent or greater surface UV flux than is produced by the Sun, which would promote stronger abiotic UV photolysis of aqueous halides than occurred during Earth's Archean era and impose stronger evolutionary selection pressures on endemic life to accommodate and utilize halogenated compounds. Ocean-bearing planets of stars with metallicities equivalent to, or greater than, the Sun should especially favor the evolution of chlorinic biospheres because of the higher relative seawater abundances of Cl, Br, and I such planets would tend to host. Directed searches for chlorinic biospheres should probably focus on G0-G2, F, and A spectral class stars that have bulk metallicities of +0.0 Dex or greater.

Haas JR

2010-11-01

390

DETERMINING REFLECTANCE SPECTRA OF SURFACES AND CLOUDS ON EXOPLANETS  

Energy Technology Data Exchange (ETDEWEB)

Planned missions will spatially resolve temperate terrestrial planets from their host star. Although reflected light from such a planet encodes information about its surface, it has not been shown how to establish surface characteristics of a planet without assuming known surfaces to begin with. We present a reanalysis of disk-integrated, time-resolved, multiband photometry of Earth obtained by the Deep Impact spacecraft as part of the EPOXI Mission of Opportunity. We extract reflectance spectra of clouds, ocean, and land without a priori knowledge of the numbers or colors of these surfaces. We show that the inverse problem of extracting surface spectra from such data is a novel and extreme instance of spectral unmixing, a well-studied problem in remote sensing. Principal component analysis is used to determine an appropriate number of model surfaces with which to interpret the data. Shrink-wrapping a simplex to the color excursions of the planet yields a conservative estimate of the planet's endmember spectra. The resulting surface maps are unphysical, however, requiring negative or larger-than-unity surface coverage at certain locations. Our ''rotational unmixing'' supersedes the endmember analysis by simultaneously solving for the surface spectra and their geographical distributions on the planet, under the assumption of diffuse reflection and known viewing geometry. We use a Markov Chain Monte Carlo to determine best-fit parameters and their uncertainties. The resulting albedo spectra are similar to clouds, ocean, and land seen through a Rayleigh-scattering atmosphere. This study suggests that future direct-imaging efforts could identify and map unknown surfaces and clouds on exoplanets.

Cowan, Nicolas B.; Strait, Talia E., E-mail: n-cowan@northwestern.edu [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, 2131 Tech Dr., IL 60208 (United States)

2013-03-01

391

DETERMINING REFLECTANCE SPECTRA OF SURFACES AND CLOUDS ON EXOPLANETS  

International Nuclear Information System (INIS)

[en] Planned missions will spatially resolve temperate terrestrial planets from their host star. Although reflected light from such a planet encodes information about its surface, it has not been shown how to establish surface characteristics of a planet without assuming known surfaces to begin with. We present a reanalysis of disk-integrated, time-resolved, multiband photometry of Earth obtained by the Deep Impact spacecraft as part of the EPOXI Mission of Opportunity. We extract reflectance spectra of clouds, ocean, and land without a priori knowledge of the numbers or colors of these surfaces. We show that the inverse problem of extracting surface spectra from such data is a novel and extreme instance of spectral unmixing, a well-studied problem in remote sensing. Principal component analysis is used to determine an appropriate number of model surfaces with which to interpret the data. Shrink-wrapping a simplex to the color excursions of the planet yields a conservative estimate of the planet's endmember spectra. The resulting surface maps are unphysical, however, requiring negative or larger-than-unity surface coverage at certain locations. Our ''rotational unmixing'' supersedes the endmember analysis by simultaneously solving for the surface spectra and their geographical distributions on the planet, under the assumption of diffuse reflection and known viewing geometry. We use a Markov Chain Monte Carlo to determine best-fit parameters and their uncertainties. The resulting albedo spectra are similar to clouds, ocean, and land seen through a Rayleigh-scattering atmosphere. This study suggests that future direct-imaging efforts could identify and map unknown surfaces and clouds on exoplanets.

2013-03-01

392

Determining Reflectance Spectra of Surfaces and Clouds on Exoplanets  

Science.gov (United States)

Planned missions will spatially resolve temperate terrestrial planets from their host star. Although reflected light from such a planet encodes information about its surface, it has not been shown how to establish surface characteristics of a planet without assuming known surfaces to begin with. We present a reanalysis of disk-integrated, time-resolved, multiband photometry of Earth obtained by the Deep Impact spacecraft as part of the EPOXI Mission of Opportunity. We extract reflectance spectra of clouds, ocean, and land without a priori knowledge of the numbers or colors of these surfaces. We show that the inverse problem of extracting surface spectra from such data is a novel and extreme instance of spectral unmixing, a well-studied problem in remote sensing. Principal component analysis is used to determine an appropriate number of model surfaces with which to interpret the data. Shrink-wrapping a simplex to the color excursions of the planet yields a conservative estimate of the planet's endmember spectra. The resulting surface maps are unphysical, however, requiring negative or larger-than-unity surface coverage at certain locations. Our "rotational unmixing" supersedes the endmember analysis by simultaneously solving for the surface spectra and their geographical distributions on the planet, under the assumption of diffuse reflection and known viewing geometry. We use a Markov Chain Monte Carlo to determine best-fit parameters and their uncertainties. The resulting albedo spectra are similar to clouds, ocean, and land seen through a Rayleigh-scattering atmosphere. This study suggests that future direct-imaging efforts could identify and map unknown surfaces and clouds on exoplanets.

Cowan, Nicolas B.; Strait, Talia E.

2013-03-01

393

Revised Orbit and Transit Exclusion for HD 114762b  

CERN Document Server

Transiting planets around bright stars have allowed the detailed follow-up and characterization of exoplanets, such as the study of exoplanetary atmospheres. The Transit Ephemeris Refinement and Monitoring Survey (TERMS) is refining the orbits of the known exoplanets to confirm or rule out both transit signatures and the presence of additional companions. Here we present results for the companion orbiting HD 114762 in an eccentric 84 day orbit. Radial velocity analysis performed on 19 years of Lick Observatory data constrain the uncertainty in the predicted time of mid-transit to ~5 hours, which is less than the predicted one-half day transit duration. We find no evidence of additional companions in this system. New photometric observations with one of our Automated Photoelectric Telescopes (APTs) at Fairborn Observatory taken during a revised transit time for companion b, along with 23 years of nightly automated observations, allow us to rule out on-time central transits to a limit of ~0.001 mag. Early or la...

Kane, Stephen R; Dragomir, Diana; Fischer, Debra A; Howard, Andrew W; Wang, Xuesong; Wright, Jason T

2011-01-01

394

Pathway Toward a Mid-Infrared Interferometer for the Direct Characterization of Exoplanets  

CERN Document Server

We recognize the need for the characterization of exoplanets in reflected light in the visible and in the IR termal emission. But for the thermal infrared we also recognize the difficulty of an interferometric nuller We nevertheless endorse the need for future interferometers. We propose a new, realistic, pathway to satisfy both goals, thermal infrared studies and interferometric architectures.

Schneider, Jean

2009-01-01

395

CHARA Array Measurements of the Angular Diameters of Exoplanet Host Stars  

CERN Multimedia

We have measured the angular diameters for a sample of 24 exoplanet host stars using Georgia State University's CHARA Array interferometer. We use these improved angular diameters together with Hipparcos parallax measurements to derive linear radii and to estimate the stars' evolutionary states.

Baines, Ellyn K; Brummelaar, Theo A ten; Turner, Nils H; Sturmann, Judit; Sturmann, Laszlo; Goldfinger, P J; Ridgway, Stephen T

2008-01-01

396

A Common Proper Motion Companion to the Exoplanet Host 51 Pegasi  

CERN Multimedia

The exoplanet host 51 Pegasi has a widely separated red dwarf companion. Two other, far more distant, stars are also co-moving with this star, showing that they are at least of common Galactic orbit due to a common origin.

Greaves, J

2010-01-01

397

Infrared Detection and Characterization of Debris Disks, Exozodiacal Dust, and Exoplanets: The FKSI Mission Concept  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for a nulling interferometer for the near-to-mid-infrared spectral region. FKSI is conceived as a mid-sized strategic or Probe class mission. FKSI has been endorsed by the Exoplanet Community Forum 2008 as such a mission and has b...

Danchi, W. C.; Barry, R. K.; Lopez, B.; Rinehart, S. A.; Absil, Olivier; Augereau, J.; Beust, H.; Bonfils, X.; Bordé, P.

398

The timescale for giant planet formation : constraints from the rotational evolution of exoplanet host stars  

CERN Multimedia

The timescale over which planets may form in the circumstellar disks of young stars is one of the main issues of current planetary formation models. We present here new constraints on planet formation timescales derived from the rotational evolution of exoplanet host stars.

Bouvier, Jerome

2008-01-01

399

On advanced estimation techniques for exoplanet detection and characterization using ground-based coronagraphs  

Science.gov (United States)

The direct imaging of planets around nearby stars is exceedingly difficult. Only about 14 exoplanets have been imaged to date that have masses less than 13 times that of Jupiter. The next generation of planet-finding coronagraphs, including VLT-SPHERE, the Gemini Planet Imager, Palomar P1640, and Subaru HiCIAO have predicted contrast performance of roughly a thousand times less than would be needed to detect Earth-like planets. In this paper we review the state of the art in exoplanet imaging, most notably the method of Locally Optimized Combination of Images (LOCI), and we investigate the potential of improving the detectability of faint exoplanets through the use of advanced statistical methods based on the concepts of the ideal observer and the Hotelling observer. We propose a formal comparison of techniques using a blind data challenge with an evaluation of performance using the Receiver Operating Characteristic (ROC) and Localization ROC (LROC) curves. We place particular emphasis on the understanding and modeling of realistic sources of measurement noise in ground-based AO-corrected coronagraphs. The work reported in this paper is the result of interactions between the co-authors during a week-long workshop on exoplanet imaging that was held in Squaw Valley, California, in March of 2012.

Lawson, Peter R.; Poyneer, Lisa; Barrett, Harrison; Frazin, Richard; Caucci, Luca; Devaney, Nicholas; Furenlid, Lars; G?adysz, Szymon; Guyon, Olivier; Krist, John; Maire, Jérôme; Marois, Christian; Mawet, Dimitri; Mouillet, David; Mugnier, Laurent; Pearson, Iain; Perrin, Marshal