WorldWideScience
1

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

CERN Document Server

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

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

2010-01-01

2

A SHORT-PERIOD CENSOR OF SUB-JUPITER MASS EXOPLANETS WITH LOW DENSITY  

International Nuclear Information System (INIS)

Despite the existence of many short-period hot Jupiters, there is not one hot Neptune with an orbital period less than 2.5 days. Here, we discuss a cluster analysis of the currently known 106 transiting exoplanets to investigate a possible explanation for this observation. We find two distinct clusters in the mass-density space, one with hot Jupiters with a wide range of orbital periods (0.8-114 days) and a narrow range of planet radii (1.2 ± 0.2 RJ ) and another one with a mixture of super-Earths, hot Neptunes, and hot Jupiters, exhibiting a surprisingly narrow period distribution (3.7 ± 0.8 days). These two clusters follow strikingly different distributions in the period-radius parameter plane. The branch of sub-Jupiter mass exoplanets is censored by the orbital period at the large-radius end: no planets with mass between 0.02 and 0.8 MJ or with radius between 0.25 and 1.0 RJ are known with Porb < 2.5 days. This clustering is not predicted by current theories of planet formation and evolution, which we also review briefly.

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

CERN Document Server

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

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

2012-01-01

4

Transiting Exoplanets with JWST  

OpenAIRE

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 p...

Seager, S.; Deming, D.; Valenti, J. A.

2008-01-01

5

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

International Nuclear Information System (INIS)

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

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-08-01

7

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

Science.gov (United States)

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 MJup, 1.06 RJup) in a 3.868-d period around an active, ˜1-Gyr, mid-K dwarf. ROSAT detected X-rays 60±27 arcsec from WASP-69. If the star is the source then the planet could be undergoing mass-loss at a rate of ˜1012 g s-1. This is one to two orders of magnitude higher than the evaporation rate estimated for HD 209458b and HD 189733b, both of which have exhibited anomalously large Lyman ? absorption during transit. WASP-70Ab is a sub-Jupiter-mass planet (0.59 MJup, 1.16 RJup) in a 3.713-d orbit around the primary of a spatially resolved, 9-10-Gyr, G4+K3 binary, with a separation of 3.3 arcsec (?800 au). WASP-84b is a sub-Jupiter-mass planet (0.69 MJup, 0.94 RJup) in an 8.523-d orbit around an active, ˜1-Gyr, early-K dwarf. Of the transiting planets discovered from the ground to date, WASP-84b has the third-longest period. For the active stars WASP-69 and WASP-84, we pre-whitened the radial velocities using a low-order harmonic series. We found that this reduced the residual scatter more than did the oft-used method of pre-whitening with a fit between residual radial velocity and bisector span. The system parameters were essentially unaffected by pre-whitening.

Anderson, D. R.; Collier Cameron, A.; Delrez, L.; Doyle, A. P.; Faedi, F.; Fumel, A.; Gillon, M.; Gómez Maqueo Chew, Y.; 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.

2014-12-01

8

KOI-183b: a half-Jupiter mass planet transiting a very old solar-like star  

CERN Document Server

We report the spectroscopic confirmation of the Kepler object of interest KOI-183b (also known as KOI-183.01), a half-Jupiter mass planet transiting an old solar-like star every 2.7 days. Our analysis is the first to combine the full Kepler photometry (quarters 1-17) with high-precision radial velocity measurements taken with the FIES spectrograph at the Nordic Optical Telescope. We simultaneously modelled the photometric and spectroscopic data-sets using Bayesian approach coupled with Markov chain Monte Carlo sampling. We found that the Kepler pre-search data conditioned (PDC) light curve of KOI-183 exhibits quarter-to-quarter systematic variations of the transit depth, with a peak-to-peak amplitude of about 4.3 % and seasonal trends reoccurring every four quarters. We attributed these systematics to an incorrect assessment of the quarterly variation of the crowding metric. The host star KOI-183 is a G4 dwarf with $M_\\star=0.85\\pm0.04$ M$_\\rm{Sun}$, $R_\\star=0.95\\pm0.04$ R$_\\rm{Sun}$, $T_\\mathrm{eff}=5560\\pm...

Gandolfi, D; Deeg, H J; Lanza, A F; Fridlund, M; Moroni, P G Prada; Alonso, R; Augusteijn, T; Cabrera, J; Evans, T; Geier, S; Hatzes, A P; Holczer, T; Hoyer, S; Kangas, T; Mazeh, T; Pagano, I; Tal-Or, L; Tingley, B

2014-01-01

9

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

10

Kepler-423b: a half-Jupiter mass planet transiting a very old solar-like star  

Science.gov (United States)

We report the spectroscopic confirmation of the Kepler object of interest KOI-183.01 (Kepler-423b), a half-Jupiter mass planet transiting an old solar-like star every 2.7 days. Our analysis is the first to combine the full Kepler photometry (quarters 1-17) with high-precision radial velocity measurements taken with the FIES spectrograph at the Nordic Optical Telescope. We simultaneously modelled the photometric and spectroscopic data-sets using Bayesian approach coupled with Markov chain Monte Carlo sampling. We found that the Kepler pre-search data conditioned light curve of Kepler-423 exhibits quarter-to-quarter systematic variations of the transit depth, with a peak-to-peak amplitude of ~4.3% and seasonal trends reoccurring every four quarters. We attributed these systematics to an incorrect assessment of the quarterly variation of the crowding metric. The host star Kepler-423 is a G4 dwarf with M? = 0.85 ± 0.04 M?, R? = 0.95 ± 0.04 R?, Teff= 5560 ± 80 K, [M/H] = - 0.10 ± 0.05 dex, and with an age of 11 ± 2 Gyr. The planet Kepler-423b has a mass of Mp= 0.595 ± 0.081MJup and a radius of Rp= 1.192 ± 0.052RJup, yielding a planetary bulk density of ?p = 0.459 ± 0.083 g cm-3. The radius of Kepler-423b is consistent with both theoretical models for irradiated coreless giant planets and expectations based on empirical laws. The inclination of the stellar spin axis suggests that the system is aligned along the line of sight. We detected a tentative secondary eclipse of the planet at a 2? confidence level (?Fec = 14.2 ± 6.6 ppm) and found that the orbit might have asmall non-zero eccentricity of 0.019+0.028-0.014. With a Bond albedo of AB = 0.037 ± 0.019, Kepler-423b is one of the gas-giant planets with the lowest albedo known so far. Based on observations obtained with the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias, in time allocated by OPTICON and the Spanish Time Allocation Committee (CAT).The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement number RG226604 (OPTICON) and 267251 (AstroFIt).

Gandolfi, D.; Parviainen, H.; Deeg, H. J.; Lanza, A. F.; Fridlund, M.; Prada Moroni, P. G.; Alonso, R.; Augusteijn, T.; Cabrera, J.; Evans, T.; Geier, S.; Hatzes, A. P.; Holczer, T.; Hoyer, S.; Kangas, T.; Mazeh, T.; Pagano, I.; Tal-Or, L.; Tingley, B.

2015-04-01

11

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

12

Transiting Exoplanet Survey Satellite (TESS)  

Science.gov (United States)

The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey, TESS will monitor more than 500,000 stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances. No ground-based survey can achieve this feat. A large fraction of TESS target stars will be 30-100 times brighter than those observed by Kepler satellite, and therefore TESS . planets will be far easier to characterize with follow-up observations. TESS will make it possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. TESS will provide prime targets for observation with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future. TESS data will be released with minimal delay (no proprietary period), inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the very nearest and brightest main-sequence stars hosting transiting exoplanets, thus providing future observers with the most favorable targets for detailed investigations.

Ricker, G. R.; Clampin, M.; Latham, D. W.; Seager, S.; Vanderspek, R. K.; Villasenor, J. S.; Winn, J. N.

2012-01-01

13

The Transiting Exoplanet Survey Satellite  

OpenAIRE

The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, TESS will employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with I = 4-13 for temporary drops in brightness caused by p...

Ricker, George R.; Winn, Joshua N.; Vanderspek, Roland; Latham, David W.; Bakos, Gaspar A.; Bean, Jacob L.; Berta-thompson, Zachory K.; Brown, Timothy M.; Buchhave, Lars; Butler, Nathaniel R.; Butler, R. Paul; Chaplin, William J.; Charbonneau, David; Christensen-dalsgaard, Jorgen; Clampin, Mark

2014-01-01

14

Young Exoplanet Transit Initiative (YETI)  

CERN Document Server

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

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

2011-01-01

15

Transiting Exoplanet Survey Satellite (TESS)  

DEFF Research Database (Denmark)

The Transiting Exoplanet Survey Satellite (TESS ) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, TESS will employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with IC (approximately less than) 13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from one month to one year, depending mainly on the star's ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10-100 times brighter than those surveyed by thepioneering Kepler mission. This will make TESS planets easier to characterize with follow-up observations. TESS is expected to find more than a thousand planets smaller than Neptune, including dozens that are comparable in size to the Earth. Public data releases will occur every four months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest stars hosting transiting planets, which will endure as highly favorable targets for detailed investigations.

Ricker, George R.; Winn, Joshua N.

2014-01-01

16

Transiting Exoplanet Survey Satellite (TESS)  

Science.gov (United States)

The Transiting Exoplanet Survey Satellite (TESS ) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, TESS will employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with IC (approximately less than) 13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from one month to one year, depending mainly on the star's ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10-100 times brighter than those surveyed by the pioneering Kepler mission. This will make TESS planets easier to characterize with follow-up observations. TESS is expected to find more than a thousand planets smaller than Neptune, including dozens that are comparable in size to the Earth. Public data releases will occur every four months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest stars hosting transiting planets, which will endure as highly favorable targets for detailed investigations.

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

2014-08-01

17

The SuperWASP exoplanet transit survey  

Science.gov (United States)

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

Smith, A. M. S.; WASP Consortium

2014-03-01

18

Nightside pollution of exoplanet transit depths  

Science.gov (United States)

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 relative to the host star, increasing towards 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 light curve, which is essentially a self-blend. 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 the case where exoplanet phase curves have been measured, in particular for HD 189733b. For other systems, it may be possible to make a first-order correction by using temperature estimates of the planet. Unless the effect is accounted for, transmission spectra will also be polluted by nightside emission, and we estimate that a Spitzer broad-band spectrum on a bright target is altered at the 1? level. Using archived Spitzer measurements, we show that the effect respectively increases the 8.0-?m and 24.0-?m transit depths by 1? and 0.5? per transit for HD 189733b. Consequently, we estimate that this would be ~5-10? effect for near future James Webb Space Telescope observations.

Kipping, David M.; Tinetti, Giovanna

2010-10-01

19

Nightside Pollution of Exoplanet Transit Depths  

CERN Document Server

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

20

Mass-loss rates for transiting exoplanets  

Science.gov (United States)

Exoplanets at small orbital distances from their host stars are submitted to intense levels of energetic radiations, X-rays, and extreme ultraviolet (EUV). Depending on the masses and densities of the planets and on the atmospheric heating efficiencies, the stellar energetic inputs can lead to atmospheric mass loss. These evaporation processes are observable in the ultraviolet during planetary transits. The aim of the present work is to quantify the mass-loss rates (?), heating efficiencies (?), and lifetimes for the whole sample of transiting exoplanets, now including hot Jupiters, hot Neptunes, and hot super-Earths. The mass-loss rates and lifetimes are estimated from an "energy diagram" for exoplanets, which compares the planet gravitational potential energy to the stellar X/EUV energy deposited in the atmosphere. We estimate the mass-loss rates of all detected transiting planets to be within 106 to 1013 g s-1 for various conservative assumptions. High heating efficiencies would imply that hot exoplanets such the gas giants WASP-12b and WASP-17b could be completely evaporated within 1 Gyr. We also show that the heating efficiency can be constrained when ? is inferred from observations and the stellar X/EUV luminosity is known. This leads us to suggest that ? ? 100% in the atmosphere of the hot Jupiter HD 209458b, while it could be lower for HD 189733b. Simultaneous observations of transits in the ultraviolet and X-rays are necessary to further constrain the exospheric properties of exoplanets. Table 1 is available in electronic form at http://www.aanda.org

Ehrenreich, D.; Désert, J.-M.

2011-05-01

21

WASP-26b: A 1-Jupiter-mass planet around an early-G-type star  

CERN Document Server

We report the discovery of WASP-26b, a moderately over-sized Jupiter-mass exoplanet transiting its 11.3-magnitude early-G-type host star (1SWASP J001824.70-151602.3; TYC 5839-876-1) every 2.7566 days. A simultaneous fit to transit photometry and radial-velocity measurements yields a planetary mass of 1.02 +/- 0.03 M_Jup and radius of 1.32 +/- 0.08 R_Jup. The host star, WASP-26, has a mass of 1.12 +/- 0.03 M_sun and a radius of 1.34 +/- 0.06 R_sun and is in a visual double with a fainter K-type star. The two stars are at least a common-proper motion pair with a common distance of around 250 +/- 15 pc and an age of 6 +/- 2 Gy.

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

2010-01-01

22

Mass-loss rates for transiting exoplanets  

OpenAIRE

Exoplanets at small orbital distances from their host stars are submitted to intense levels of energetic radiations, X-rays and extreme ultraviolet (EUV). Depending on the masses and densities of the planets and on the atmospheric heating efficiencies, the stellar energetic inputs can lead to atmospheric mass loss. These evaporation processes are observable in the ultraviolet during planetary transits. The aim of the present work is to quantify the mass-loss rates (dm/dt), h...

Ehrenreich, David; De?sert, Jean-michel

2011-01-01

23

The Transiting Exoplanet Survey Satellite: Mission Status  

Science.gov (United States)

The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey of the solar neighborhood, TESS will monitor more than 200,000 bright stars for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances.TESS stars will typically be 30-100 times brighter than those surveyed by the Kepler satellite; thus, TESS planets will be far easier to characterize with follow-up observations. For the first time it will be possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars. Full frame images with a cadence of 30 minutes or less will provide precise photometric information for more than 20 million stars during observation sessions of several weeks. The brighter TESS stars will potentially yield valuable asteroseismic information as a result of monitoring at a rapid cadence of 2 minute or less. An extended survey by TESS of regions surrounding the North and South Ecliptic Poles will provide prime exoplanet targets for characterization with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future.TESS will issue data releases every 4 months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest main-sequence stars hosting transiting exoplanets, which will endure as the most favorable targets for detailed future investigations.TESS has a planned launch date in 2017 as a NASA Astrophysics Explorer mission.

Ricker, George R.; TESS Team

2015-01-01

24

Modeling transiting exoplanet and spots For interferometric study  

Science.gov (United States)

Up to now, many techniques have been developed to detect and observe exoplanets, the radial velocity (RV) method being the most prolific one. However, stellar magnetic spots can mimic an exoplanet transit signal and lead to a false detection. A few models have already been developed to constrain the different signature of exoplanets and spots, but they only concern RV measurements or photometry. An interferometric approach, with high angular resolution capabilities, could resolve this problem. Optical interferometry is a powerful method to measure accurate stellar diameters, and derive fundamental parameters of stars and exoplanets minimum masses. We have built an analytical code able to calculate visibility moduli and closure phases of stars with a transiting exoplanet, to be compared with a star with no exoplanet. From the difference of interferometric signal, we can derive the presence of the exoplanet, but this requires that the star is resolved enough. We have tested this code with current available facilities like VEGA/CHARA and determined which already discovered exoplanets systems can be resolved enough to test this method. To make a more general study, we also tested different parameters (exoplanet and stellar diameters, exoplanet position) that can lead to a variation of the minimum baseline length required to see the exoplanet signal on the visibility modulus and the phase. Stellar spots act in the same way, but the difference of local intensity between an exoplanet transit and a spot can easily be studied thanks to the interferometric measurements.

Ligi, Roxanne; Mourard, Denis; Perraut, Karine; Bério, Philippe; Bigot, Lionel; Chiavassa, Andrea; Lagrange, Anne-Marie; Nardetto, Nicolas

2014-08-01

25

TERMS PHOTOMETRY OF KNOWN TRANSITING EXOPLANETS  

International Nuclear Information System (INIS)

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

26

The WASP-South search for transiting exoplanets  

Directory of Open Access Journals (Sweden)

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

Queloz D.

2011-02-01

27

TASTE: The Asiago Survey for Timing transit variations of Exoplanets  

OpenAIRE

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...

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

2010-01-01

28

Characterization of Transiting Exoplanets by Way of Differential Photometry  

Science.gov (United States)

This paper describes a simple activity for plotting and characterizing the light curve from an exoplanet transit event by way of differential photometry analysis. Using free digital imaging software, participants analyse a series of telescope images with the goal of calculating various exoplanet parameters, including size, orbital radius and…

Cowley, Michael; Hughes, Stephen

2014-01-01

29

Transiting exoplanets and magnetic spots characterized with optical interferometry  

Science.gov (United States)

Context. Stellar activity causes difficulties in the characterization of transiting exoplanets. In particular, the magnetic spots present on most exoplanet host stars can lead to false detections with radial velocity, photometry, or astrometry techniques. Studies have been performed to quantify their impact on infrared interferometry, but no such studies have been performed in the visible domain. This wavelength domain, however, allows reaching better angular resolution than in the infrared and is also the wavelength most often used for spectroscopic and photometric measurements. Aims: We use a standard case to completely analyse the impact of an exoplanet and a spot on interferometric observables and relate it to current instrument capabilities, taking into account realistic achievable precisions. Methods: We built a numerical code called COMETS using analytical formulae to perform a simple comparison of exoplanet and spot signals. We explored instrumental specificities needed to detect them, such as the required baseline length, the accuracy, and signal-to-noise ratio. We also discuss the impact of exoplanet and spot parameters on squared visibility and phase: exoplanet diameter and size, exoplanet position, spot temperature, star diameter. Results: According to our study, the main improvement to achieve is the instrument sensitivity. The accuracy on squared visibilities has to be improved by a factor 10 to detect an exoplanet of 0.10 mas, leading to exoplanet of 0.05 mas, accuracies of ~0.1% and ~1° from the first null are required on squared visibilities and phases. Magnetic spots can mimic these signals, leading to false exoplanet characterization. Phase measurements from the third lobe are needed to distinguish between the spot and the exoplanet if they have the same radius. Conclusions: By increasing interferometer sensitivity, more objects will become common between interferometric and photometric targets. Furthermore, new missions such as PLATO, CHEOPS, or TESS will provide bright exoplanet host stars. Measurements will thus overlap and provide a better characterization of stellar activity and exoplanet.

Ligi, R.; Mourard, D.; Lagrange, A.-M.; Perraut, K.; Chiavassa, A.

2015-02-01

30

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.

Fang X.-S.

2011-07-01

31

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

CERN Document Server

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

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

2014-01-01

32

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.

2011-02-01

33

Characterizing Transiting Exoplanet Atmospheres with Gemini/GMOS: First Results  

Science.gov (United States)

We present the first results from a 4-year ground-based survey of nine transiting exoplanet atmospheres. The program uses the Multi-Object Spectrograph (GMOS) on both Gemini north and south to repetitively measure transit lightcurves of individual exoplanets at high spectrophotometric precision. I will present the first results from this program. We attain photometric precisions per spectral bin of 200-600 ppm. Such precision enables us to construct transmission spectra of hot Jupiters. These transmission spectra reveal the dominant upper-atmosphere absorbers in the optical bandpass. Our overarching goal is to understand the prevalence and formation of high altitude clouds and hazes, and other important atmospheric constituents.

Huitson, Catherine; Desert, Jean-Michel; Bean, Jacob; Fortney, Jonathan J.; Stevenson, Kevin B.; Bergmann, Marcel

2015-01-01

34

Exoplanets with LSST: Period Recoverability of Transiting Hot Jupiters  

Science.gov (United States)

The Large Synoptic Survey Telescope (LSST) will generate light curves for an unprecedented one billion stars across the night sky. While the LSST was not conceived or designed to find exoplanets, the data can nevertheless be exploited for that purpose. Although the LSST will have a much lower observing cadence compared to dedicated exoplanet surveys, the sheer number of stars that LSST will survey could result in a very large number of transiting exoplanet detections. In particular, LSST will probe stellar populations currently undersampled in most transit surveys, including out to extragalactic distances. Since period detection is one of the necessary criteria for transit detection, here we report on a test of the efficiency of a standard boxed-least-squares (BLS) algorithm at accurately recovering the periods of exoplanets using simulated LSST data. Specifically, we test the case of a 1 solar mass star at 7000 pc from Earth, transited by an 8-, 10-, and 12- Earth radius planet at input periods ranging from 0.5 to 20 days. At short periods, BLS was highly accurate at recovering the input period, with accuracy trailing off quickly for LSST regular cadence observation but much more gradually for "deep drilling" cadence observation. For example, in the 10-Earth radius case, we find that the transits are correctly recovered at least 50% of the time for planet periods up to 2.5 days in the regular cadence mode, and 15 days in the deep-drilling mode.

Jacklin, Savannah; Lund, Michael; Pepper, Joshua; Stassun, Keivan

2015-01-01

35

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

36

High-resolution spectroscopic follow-up of OGLE planetary transit candidates in the Galactic bulge: two possible Jupiter-mass planets and two blends  

CERN Document Server

We report the results of our campaign to follow-up spectroscopically several candidate extrasolar transiting planets from the OGLE-III survey in the direction of the Galactic center, announced in 2001 (Udalski et al 2002a,b). All of these objects present shallow and periodic dips in brightness that may be due to planetary companions. Our high-resolution Keck I/HIRES observations have revealed two interesting cases (OGLE-TR-10 with a period of 3.1 days, and OGLE-TR-58 with a period of 4.3 days) that show no radial velocity variations at the level of 100--200 m/s. If orbited by companions, their masses would be similar to Jupiter. With the information in hand (including the light curves) we are not able to rule out that these candidates are instead the result of contamination from an eclipsing binary in the same line of sight (a "blend"). We discuss also the case of OGLE-TR-56 that was recently reported by Konacki et al (2003) to have a Jupiter-size companion, based on an earlier analysis of our data, and we pr...

Konacki, M; Jha, S; Sasselov, D D; Konacki, Maciej; Torres, Guillermo

2003-01-01

37

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

38

Transiting Planets With LSST. I. Potential for LSST Exoplanet Detection  

Science.gov (United States)

The Large Synoptic Survey Telescope (LSST) is designed to meet several scientific objectives over a 10 year synoptic sky survey. Beyond its primary goals, the large amount of LSST data can be exploited for additional scientific purposes. We show that LSST data are sufficient to detect the transits of exoplanets, including planets orbiting stars that are members of stellar populations that have so far been largely unexplored. Using simulated LSST light curves, we find that existing transit detection algorithms can identify the signatures of Hot Jupiters around solar-type stars, Hot Neptunes around K-dwarfs, and (in favorable cases) Super-Earths in habitable-zone orbits of M-dwarfs. We also find that LSST may identify Hot Jupiters orbiting stars in the Large Magellanic Cloud—a remarkable possibility that would advance exoplanet science into the extragalactic regime.

Lund, Michael B.; Pepper, Joshua; Stassun, Keivan G.

2015-01-01

39

THE LOW DENSITY TRANSITING EXOPLANET WASP-15b  

International Nuclear Information System (INIS)

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

40

Transmission spectrum of Venus as a transiting exoplanet  

OpenAIRE

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 observ...

Ehrenreich, David; Vidal-madjar, Alfred; Widemann, Thomas; Gronoff, Guillaume; Tanga, Paolo; Barthe?lemy, Mathieu; Lilensten, Jean; Etangs, Alain Lecavelier Des; Arnold, Luc

2011-01-01

41

New tools and improvements in the Exoplanet Transit Database  

Directory of Open Access Journals (Sweden)

Full Text Available Comprehensive collection of the available light curves, prediction possibilities and the online model ?tting procedure, that are available via Exoplanet Transit Database became very popular in the community. In this paper we summarized the changes, that we made in the ETD during last year (including the Kepler candidates into the prediction section, modeling of an unknown planet in the model-?t section and some other small improvements. All this new tools cannot be found in the main ETD paper.

Pejcha O.

2011-02-01

42

FIVE KEPLER TARGET STARS THAT SHOW MULTIPLE TRANSITING EXOPLANET CANDIDATES  

International Nuclear Information System (INIS)

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

43

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

44

Direct Detection of Exoplanets  

OpenAIRE

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

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

2006-01-01

45

Emulating JWST Exoplanet Transit Observations in a Testbed laboratory experiment  

Science.gov (United States)

The transit technique is used for the detection and characterization of exoplanets. The combination of transit and radial velocity (RV) measurements gives information about a planet's radius and mass, respectively, leading to an estimate of the planet's density (Borucki et al. 2011) and therefore to its composition and evolutionary history. Transit spectroscopy can provide information on atmospheric composition and structure (Fortney et al. 2013). Spectroscopic observations of individual planets have revealed atomic and molecular species such as H2O, CO2 and CH4 in atmospheres of planets orbiting bright stars, e.g. Deming et al. (2013). The transit observations require extremely precise photometry. For instance, Jupiter transit results to a 1% brightness decrease of a solar type star while the Earth causes only a 0.0084% decrease (84 ppm). Spectroscopic measurements require still greater precision method is used to characterize noise and stability as it indicates shot noise limited performance. Testbed experiments are ongoing to provide quantitative information on the achievable spectroscopic precision using realistic exoplanet spectra with the goal to define optimized data acquisition sequences for use, for example, with the James Webb Space Telescope.

Touli, D.; Beichman, C. A.; Vasisht, G.; Smith, R.; Krist, J. E.

2014-12-01

46

The South Pole Exoplanet Transit Search  

Science.gov (United States)

The unique conditions and location of the South Pole make it the best place on Earth to detect transiting short-period extrasolar planets. The long winter night constant star elevation high altitude and dark sky all combine to make the expected detection efficiency almost a factor of three higher than for a comparable survey at a mid-latitude site. We have constructed an automated transit photometry system for over-winter deployment at the South Pole. The photometer uses a large-format CCD and a fast f/1.5 300 mm focal length lens to give a seven degree field-of-view. The photometer will be mounted on Mt. Stromlo Observatory's G-mount which has been operating successfully at the South Pole for several seasons. The system will operate for two winter seasons. It will monitor ~10000 stars from V=9 to 13 magnitude continuously for 6 weeks with the goal to observe two fields per dark season. We expect to detect 10 to 15 transiting extrasolar planets in two years of observations.

Caldwell, Douglas A.; Witteborn, Fred C.; Showen, Robert L.; Ninkov, Zoran; Martin, Kevin R.; Doyle, Laurance R.; Borucki, William J.

47

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

48

WASP-29b: A Saturn-sized transiting exoplanet  

CERN Document Server

We report the discovery of a Saturn-sized planet transiting a V = 11.3, K4 dwarf star every 3.9 d. 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.

Hellier, Coel; Cameron, A Collier; Gillon, M; Lendl, M; Maxted, P F L; Queloz, D; Smalley, B; Triaud, A H M J; West, R G; Brown, D J A; Enoch, B; Lister, T A; Pepe, F; Pollacco, D; Segransan, D; Udry, S

2010-01-01

49

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.

50

H? ABSORPTION IN TRANSITING EXOPLANET ATMOSPHERES  

International Nuclear Information System (INIS)

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 absorption on the net cooling rate

51

Direct Imaging of Giant Exoplanets  

Science.gov (United States)

Since the first detection of exoplanets around a Sun-like star 51 Peg in 1995, their detection and characterization are mainly led by indirect methods such as radial velocity and transit methods. However, recent progresses of observational techniques have finally enabled the direct imaging observations of giant planets of solar-system-scale orbit (with their semi-major axes less than about 50 AU) around A-type stars (e.g., Marois et al. 2008, 2010) and G-type stars (e.g., Kuzuhara et al. 2013). Direct imaging is useful to obtain the physical and atmospheric parameters of exoplanets. In fact not only colors but also a medium-resolution spectroscopy of such planets has been successfully obtained for their atmospheric characterization (Barman et al. 2013). Their masses are typically a few to ~10 Jupiter masses and they orbit at a Saturn- to-Pluto distance. Therefore, like hot-Jupiters and super-Earths they are unlike any solar-system planets, and called wide-orbit giant planets. A recent large search for planets and disk on the Subaru 8.2-m telescope (SEEDS project) has detected a 3-5 Jupiter-masses planet around a Sun-like star GJ 504 (Kuzuhara et al. 2013). It is the coolest planetary companion so far directly imaged and its near-infrared color is “bluer” than that of other directly imaged planets. In this contribution, I will review the recent progresses on direct imaging of exoplanets, highlight the results of the SEEDS project, and discuss the future developments.

Tamura, Motohide

52

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

53

Young, Jupiter-Mass Objects in Ophiuchus  

CERN Document Server

We have used 3.5 to 8 micron data from the Cores to Disks (c2d) Legacy survey and our own deep IJHKs images of a 0.5 square degree portion of the c2d fields in Ophiuchus to produce a sample of candidate young objects with probable masses between 1 and 10 Jupiter masses. The availability of photometry over whole range where these objects emit allows us to discriminate between young, extremely low-mass candidates and more massive foreground and background objects and means our survey will have fewer false positives than existing near-IR surveys. The sensitive inventory of a star forming cloud from the red to the mid-IR will allow us to constrain the IMF for these non-clustered star formation regions to well below the deuterium burning limit. For stars with fluxes in the broad gap between the 2MASS limits and our limits, our data will provide information about the photospheres. We will use the Spitzer results in combination with current disk models to learn about the presence and nature of circumstellar disks ar...

Allers, K N; Van der Bliek, N; Allard, F; Baraffe, I

2005-01-01

54

Agent Exoplanet  

Science.gov (United States)

Astronomers at Las Cumbres Observatory are investigating exoplanets - planets which orbit stars other than our Sun - and you can too. Joining Agent Exoplanet you will study known exoplanets using images taken by LCOGT’s telescopes. You'll measure the brightness of a star while a planet moves between it and our viewpoint. You can examine as many images, from as many exoplanet transit events, as you like and contribute to understanding the properties of each exoplanet.

Las Cumbres Observatory Global Telescope Network

55

Transmission spectrum of Venus as a transiting exoplanet  

Science.gov (United States)

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 ?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 ?m by Mie extinction (~5 ppm at 0.8 ?m) caused by droplets of sulfuric acid composing an upper haze layer above the main deck of clouds. These features are not expected for a terrestrial exoplanet and could help discriminating an Earth-like habitable world from a cytherean planet. Appendix A is available in electronic form at http://www.aanda.orgFull Table A.1 is only available 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/537/L2

Ehrenreich, D.; Vidal-Madjar, A.; Widemann, T.; Gronoff, G.; Tanga, P.; Barthélemy, M.; Lilensten, J.; Lecavelier Des Etangs, A.; Arnold, L.

2012-01-01

56

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

CERN Document Server

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

57

Exoplanets Galore!  

Science.gov (United States)

Eight New Very Low-Mass Companions to Solar-Type Stars Discovered at La Silla The intensive and exciting hunt for planets around other stars ("exoplanets") is continuing with great success in both hemispheres. Today, a team of astronomers of the Geneva Observatory [1] are announcing the discovery of no less than eight new, very-low mass companions to solar-type stars. The masses of these objects range from less than that of planet Saturn to about 15 times that of Jupiter. The new results were obtained by means of high-precision radial-velocity measurements with the CORALIE spectrometer at the Swiss 1.2-m Leonhard Euler telescope at the ESO La Silla Observatory. An earlier account of this research programme is available as ESO Press Release 18/98. Recent views of this telescope and its dome are available below as PR Photos 13a-c/00. This observational method is based on the detection of changes in the velocity of the central star , due to the changing direction of the gravitational pull from an (unseen) exoplanet as it orbits the star. The evaluation of the measured velocity variations allows to deduce the planet's orbit , in particular the period and the distance from the star, as well as a minimum mass [2]. The characteristics of the new objects are quite diverse. While six of them are most likely bona-fide exoplanets , two are apparently very low-mass brown-dwarfs (objects of sub-stellar mass without a nuclear energy source in their interior). From the first discovery of an exoplanet around the star 51 Pegasi in 1995 (by Michel Mayor and Didier Queloz of the present team), the exoplanet count is now already above 40. "The present discoveries complete and enlarge our still preliminary knowledge of extra-solar planetary systems, as well as the transition between planets and `brown dwarfs'" , say Mayor and Queloz, on behalf of the Swiss team. An overview of the new objects ESO PR Photo 12/00 ESO PR Photo 12/00 [Preview - JPEG: 400 x 242 pix - 76k] [Normal - JPEG: 800 x 483 pix - 184k] Caption : A representation of the sizes and shapes of the orbits of the eight new planetary and brown-dwarf candidates. The colours indicate the deduced minimum masses: about one Saturn mass or less (red); between 1 and 3 Jupiter masses (green); above 10 Jupiter masses (blue). The dashed line indicates the size of the Earth's orbit (radius 150 million km). The sizes and shapes of the orbits of the eight new planets and brown-dwarf candidates are illustrated in Photo 12/00 . More details about the individual objects are given below. A sub-saturnian planet in orbit around HD 168746 HD 168746 is a quiescent solar-like star of type G5 in the constellation Scutum (The Shield). It is slightly less massive than the Sun (0.92 solar mass) and is located at a distance of about 140 light-years. The visual magnitude is 7.9, i.e. about six times too faint to be seen with the unaided eye. The Swiss team found a new planet that orbits this star every 6.4 days, a fairly short period. The orbit is circular and the deduced minimum mass of the planet is only 80% of the mass of planet Saturn. This is only the third exoplanet detected so far with a possible sub-saturnian mass. Two planets slightly more massive than Saturn around HD 83443 and HD 108147 The planetary candidates detected around HD 83443 (visual magnitude 8.2; in the constellation Vela - the Sail) and HD 108147 (7.0 mag; Crux - the Cross) also have very low minimum masses, 0.35 and 0.34 times the mass of planet Jupiter, or 1.17 and 1.15 times that of Saturn, respectively. The companion of HD 83443 is particularly remarkable, not only by virtue of its low mass - it is also the exoplanet so far detected with the shortest period (2.986 days) and the smallest distance to the central star, only 5.7 million km (0.038 AU), i.e., 26 times smaller than the Sun-Earth distance. HD 83443 is of type K0V, it is at a distance of 141 light-years and is somewhat less massive than our Sun (0.8 solar mass). Most interestingly, a small change with time (a "drift") of the mean velocity vari

2000-05-01

58

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

CERN Document Server

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

59

Toward the Detection of Exoplanet Transits with Polarimetry  

Science.gov (United States)

In contrast to photometric transits, whose peak signal occurs at mid-transit due to occultation of the brightest region of the disk, polarimetric transits provide a signal upon ingress and egress due to occultation of the polarized stellar limb. Limb polarization, the bright corollary to limb darkening, arises from the 90° scattering angle and low optical depth experienced by photons at the limb. In addition to the ratio R p/R *, the amplitude of a polarimetric transit is expected to be controlled by the strength and width of the stellar limb polarization profile, which depend on the scattering-to-total opacity ratio at the stellar limb. We present a short list of the systems providing the highest expected signal-to-noise ratio for detection of this effect, and we draw particular attention to HD 80606b. This planet is spin/orbit misaligned, has a three-hour ingress, and has a bright parent star, which make it an attractive target. We report on test observations of an HD 80606b ingress with the POLISH2 polarimeter at the Lick Observatory Shane 3 m telescope. We conclude that unmodeled telescope systematic effects prevented polarimetric detection of this event. We outline a roadmap for further refinements of exoplanet polarimetry, whose eventual success will require a further factor of ten reduction in systematic noise.

Wiktorowicz, Sloane J.; Laughlin, Gregory P.

2014-11-01

60

Simulating Exoplanet Transit and Eclipse Observations with JWST  

Science.gov (United States)

The James Webb Space Telescope (JWST) will be a nearly ideal machine for acquiring the transmission and emission spectra of transiting exoplanets over its large wavelength range 0.7 - 28 microns. The NIRSpec, NIRCam, nTFI, and MIRI instruments will have spectroscopic capabilities that span spectral resolutions from 20 - 3000 and can cover up to 2 - 3 octaves in wavelength simultaneously. This will allow observing multiple molecular features at once, facilitating the separation of atmospheric temperature and abundance effects on spectra. Many transiting planets will also be able to be observed with both transmission and eclipse spectroscopy, providing further insights and constraints on planetary thermal structures and energy transport. Simulated JWST spectra of planets ranging from mini-Neptunes to gas giants will be presented. These simulations include planets ranging from mini-Neptunes to gas giants will be presented. These simulations include current best estimates of actual instrument throughput, resolution, spectral range, systematic noise, and random noise terms. They show that JWST will be able to determine the atmospheric parameters of a wide variety of planets, often when observing only one or a few transit or eclipse event sequences. The thermal emissions of rocky super-Earths will also be quickly detectable via mid-IR eclipse observations if such planets are found around nearby M star hosts beforehand.

Greene, Tom

2011-01-01

61

Analyzing the Orbits of Transiting Exoplanets Using Spitzer Secondary Eclipses  

Science.gov (United States)

Radial-velocity and transit-timing data can constrain the eccentricity, argument of periapsis, period, and other exoplanet orbital parameters. Including secondary-eclipse times can improve these parameters, especially eccentricity. We combined Spitzer secondary-eclipse data for HAT-P-16b and TrES-1b with existing radial-velocity and transit-timing data. For HAT-P-16b, we find that e = 0.0435 ± 0.0013, reducing the uncertainty by a factor of 4. For TrES-1b, we find that e cos ? = 0.002460 ± 0.000814, which is evidence of eccentricity not obtained by previous analyses of radial velocity data. We fit a Keplerian model to the data using Bayesian posterior sampling via a Markov-chain Monte Carlo (MCMC) algorithm to estimate the uncertainties. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA, which provided support for this work. This work was supported in part by NASA Planetary Atmospheres grant NNX13AF38G and NASA Astrophysics Data Analysis Program grant NNX12AI69G.

Foster, Andrew S.; Harrington, J.; Hardy, R. A.; Cubillos, P.; Hardin, M. R.

2013-10-01

62

AN EFFICIENT AUTOMATED VALIDATION PROCEDURE FOR EXOPLANET TRANSIT CANDIDATES  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-12-10

63

AN EFFICIENT AUTOMATED VALIDATION PROCEDURE FOR EXOPLANET TRANSIT CANDIDATES  

International Nuclear Information System (INIS)

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

64

Revisited Transit Spectroscopy of Giant Exoplanets Using HST/NICMOS  

Science.gov (United States)

Infrared transmission spectroscopy of the giant transiting exoplanets HD189733b and XO-1b using HST/NICMOS produced some of the first measurements of molecular absorptions in hot Jupiters. The molecules that were identified in the NICMOS spectra included water vapor, methane, and carbon dioxide. However, the NICMOS detections were subsequently challenged by Gibson et al. (2011) on the basis that the removal of instrumental signatures using a linear decorrelation technique was not reliable. Subsequently, transmission spectroscopy measurements in the 1.1-1.7 micron infrared region, using HST/WFC3, are proving to be robust and sensitive. The best WFC3 transmission spectroscopy now achieves a precision of better than 35 parts-per-million per wavelength channel at a spectral resolution of 0.05 microns. The WFC3 spectroscopy contradicts the published NICMOS results for planets and wavelength regions where they overlap. To illuminate this discrepancy, we are re-analyzing the NICMOS data, including some measurements not previously published, using numerical techniques developed and proven for WFC3.

Deming, Drake; Wilkins, A. N.; Madhusudhan, N.

2014-01-01

65

Trajectory Design for the Transiting Exoplanet Survey Satellite (TESS)  

Science.gov (United States)

The Transiting Exoplanet Survey Satellite (TESS) is a National Aeronautics and Space Administration (NASA) mission launching in 2017. TESS will travel in a highly eccentric orbit around Earth, with initial perigee radius near 17 Earth radii (Re) and apogee radius near 59 Re. The orbit period is near 2:1 resonance with the Moon, with apogee nearly 90 degrees out-of-phase with the Moon, in a configuration that has been shown to be operationally stable. TESS will execute phasing loops followed by a lunar flyby, with a final maneuver to achieve 2:1 resonance with the Moon. The goals of a resonant orbit with long-term stability, short eclipses and limited oscillations of perigee present significant challenges to the trajectory design. To rapidly assess launch opportunities, we adapted the SWM76 launch window tool to assess the TESS mission constraints. To understand the long-term dynamics of such a resonant orbit in the Earth-Moon system we employed Dynamical Systems Theory in the Circular Restricted 3-Body Problem (CR3BP). For precise trajectory analysis we use a high-fidelity model and multiple shooting in the General Mission Analysis Tool (GMAT) to optimize the maneuver delta-V and meet mission constraints. Finally we describe how the techniques we have developed can be applied to missions with similar requirements.

Dichmann, Donald J.; Parker, Joel; Williams, Trevor; Mendelsohn, Chad

2014-01-01

66

Trajectory Design for the Transiting Exoplanet Survey Satellite  

Science.gov (United States)

The Transiting Exoplanet Survey Satellite (TESS) is a National Aeronautics and Space Administration (NASA) mission, scheduled to be launched in 2017. TESS will travel in a highly eccentric orbit around Earth, with initial perigee radius near 17 Earth radii (Re) and apogee radius near 59 Re. The orbit period is near 2:1 resonance with the Moon, with apogee nearly 90 degrees out-of-phase with the Moon, in a configuration that has been shown to be operationally stable. TESS will execute phasing loops followed by a lunar flyby, with a final maneuver to achieve 2:1 resonance with the Moon. The goals of a resonant orbit with long-term stability, short eclipses and limited oscillations of perigee present significant challenges to the trajectory design. To rapidly assess launch opportunities, we adapted the Schematics Window Methodology (SWM76) launch window analysis tool to assess the TESS mission constraints. To understand the long-term dynamics of such a resonant orbit in the Earth-Moon system we employed Dynamical Systems Theory in the Circular Restricted 3-Body Problem (CR3BP). For precise trajectory analysis we use a high-fidelity model and multiple shooting in the General Mission Analysis Tool (GMAT) to optimize the maneuver delta-V and meet mission constraints. Finally we describe how the techniques we have developed can be applied to missions with similar requirements. Keywords: resonant orbit, stability, lunar flyby, phasing loops, trajectory optimization

Dichmann, Donald J.; Parker, Joel J. K.; Williams, Trevor W.; Mendelsohn, Chad R.

2014-01-01

67

Exoplanet HAT-P-11b Secondary Transit Observations  

Science.gov (United States)

We have conducted secondary eclipse observations of exoplanet HAT--11b, recently discovered by proposal G. Bakos and his colleagues. HAT-P-11b is the smallest transiting extrasolar planet yet found and one of only two known exo-Neptunes. We have observed the system at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Once the secondary eclipse is located through analysis of the data, we will make a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-1lb has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi major axis 0.053 AU. Measurements of the secondary eclipse will clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. A precise determination of the orbit phase for the secondary eclipse will also be of great utility for Kepler observations of this system at visible wavelengths.

Barry, Richard K., Jr.

2010-01-01

68

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

OpenAIRE

Infrared transmission and emission spectroscopy of exoplanets, recorded from primary transit and secondary eclipse measurements, indicate the presence of the most abundant carbon and oxygen molecular species (H2O, CH4, CO, and CO2) in a few exoplanets. However, efforts to constrain the molecular abundances to within several orders of magnitude are thwarted by the broad range of degenerate solutions that fit the data. Here we explore, with radiative transfer models and analyt...

Griffith, Caitlin A.

2013-01-01

69

State of the art on the detection of exoplanets by the transit method with small instruments  

Science.gov (United States)

In this paper we report the all exoplanets that are discovered to date by the transit method. Also, we present the limit of detection by this method using the small instruments, and the specific information that can be deducted from the transit method. In addition, we present the detection and characterization of HD 189733b, the peculiarity of this exoplanet is that the flow of the target star is decreased significantly (?3%) during the transit. We determined the radius of the exoplanet 1.27 ± 0.03 RJ, the impact parameter 0.70 ± 0.02, and the inclination of the orbit 85.4 ± 0.1°. The transit of the extrasolar planet HD 189733b is already done using the larger telescope. In this study, we used during the observation a telescope of modest size.

Daassou, A.; Benkhaldoun, Z.; Elazhari, Y.

2010-10-01

70

C/O Ratios of Stars with Transiting Hot Jupiter Exoplanets  

CERN Document Server

The relative abundances of carbon and oxygen have long been recognized as fundamental diagnostics of stellar chemical evolution. Now, the growing number of exoplanet observations enable estimation of these elements in exoplanetary atmospheres. In hot Jupiters, the C/O ratio affects the partitioning of carbon in the major observable molecules, making these elements diagnostic of temperature structure and composition. Here we present measurements of carbon and oxygen abundances in 16 stars that host transiting hot Jupiter exoplanets, and compare our C/O ratios to those measured in larger samples of host stars, as well as those estimated for the corresponding exoplanet atmospheres. With standard stellar abundance analysis we derive stellar parameters as well as [C/H] and [O/H] from multiple abundance indicators, including synthesis fitting of the [O I] 6300 {\\AA} line and NLTE corrections for the O I triplet. Our results, in agreement with recent suggestions, indicate that previously-measured exoplanet host star...

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

2014-01-01

71

On the characterization of transiting exoplanets and magnetic spots with optical interferometry  

CERN Document Server

Stellar activity causes difficulties in the characterization of transiting exoplanets. Studies have been performed to quantify its impact on infrared interferometry, but not in the visible domain, which however allows reaching better angular resolution and is also the one mostly used for spectroscopic and photometric measurements. We use a textbook case to make a complete analysis of the impact of an exoplanet and a spot on interferometric observables and relate it to current instruments capabilities, taking into account realistic achievable precisions. We have built a numerical code called COMETS using analytical formulae to perform a simple comparison of exoplanets and spots' signals. We explore instrumental specificities needed to detect them, like the baseline length required, the accuracy and SNR. We also discuss the impact of exoplanets and spot's parameters on squared visibility and phase. We find that the main improvement to bring is the sensitivity of instruments. The accuracy on squared visibilities...

Ligi, R; Lagrange, A -M; Perraut, K; Chiavassa, A

2014-01-01

72

Oukaimeden Observatory: detection of exoplanet HD 189733b by the transit method  

Science.gov (United States)

In this paper we report the detection and characterization of HD 189733b, the peculiarity of this exoplanet is that the flow of the target star is decreased significantly (~ 3%) during the transit. We determined the radius of the exoplanet 1.27 +/- 0.03 RJ, the impact parameter 0.70 +/- 0.02, and the inclination of the orbit 85.4 +/- 0.1°. The transit of the extrasolar planet HD 189733b is already done using the larger telescope. In this study, we used during the observation a telescope of modest size.

Daassou, A.; Benkhaldoun, Z.; Elazhari, Y.; Sabil, M.

2010-07-01

73

Observations of Transiting Exoplanets with the James Webb Space Telescope (JWST)  

Science.gov (United States)

This article summarizes a workshop held on March, 2014, on the potential of the James Webb Space Telescope (JWST) to revolutionize our knowledge of the physical properties of exoplanets through transit observations. JWST's unique combination of high sensitivity and broad wavelength coverage will enable the accurate measurement of transits with high signal-to-noise ratio (S/N). Most importantly, JWST spectroscopy will investigate planetary atmospheres to determine atomic and molecular compositions, to probe vertical and horizontal structure, and to follow dynamical evolution, i.e., exoplanet weather. JWST will sample a diverse population of planets of varying masses and densities in a wide variety of environments characterized by a range of host star masses and metallicities, orbital semi-major axes, and eccentricities. A broad program of exoplanet science could use a substantial fraction of the overall JWST mission.

Beichman, Charles; Benneke, Bjoern; Knutson, Heather; Smith, Roger; Lagage, Pierre-Olivier; Dressing, Courtney; Latham, David; Lunine, Jonathan; Birkmann, Stephan; Ferruit, Pierre; Giardino, Giovanna; Kempton, Eliza; Carey, Sean; Krick, Jessica; Deroo, Pieter D.; Mandell, Avi; Ressler, Michael E.; Shporer, Avi; Swain, Mark; Vasisht, Gautam; Ricker, George; Bouwman, Jeroen; Crossfield, Ian; Greene, Tom; Howell, Steve; Christiansen, Jessie; Ciardi, David; Clampin, Mark; Greenhouse, Matt; Sozzetti, Alessandro; Goudfrooij, Paul; Hines, Dean; Keyes, Tony; Lee, Janice; McCullough, Peter; Robberto, Massimo; Stansberry, John; Valenti, Jeff; Rieke, Marcia; Rieke, George; Fortney, Jonathan; Bean, Jacob; Kreidberg, Laura; Ehrenreich, David; Deming, Drake; Albert, Loïc; Doyon, René; Sing, David

2014-12-01

74

The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b  

OpenAIRE

We present the results of a transcontinental campaign to observe the 2009 June 5 transit of the exoplanet HD 80606b. We report the first detection of the transit ingress, revealing the transit duration to be 11.64 ± 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibit an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. The Keck data show that the projected spi...

Winn, Joshua N.; Howard, Andrew W.; Johnson, John Asher; Marcy, Geoffrey W.; Gazak, J. Zachary; Starkey, Donn; Ford, Eric B.; Colon, Knicole D.; Reyes, Francisco; Nortmann, Lisa; Dreizler, Stefan; Odewahn, Stephen; Welsh, William F.; Kadakia, Shimonee; Vanderbei, Robert J.

2009-01-01

75

Hubble/WFC3 Spectroscopy of the Transiting Exoplanets WASP-19b and WASP-17b  

Science.gov (United States)

Measurements of transiting exoplanets that target extremes in parameter space offer the best chance to disentangle the structure and composition of the atmospheres of hot Jupiters. WASP-19b is one of the hottest exoplanets discovered to date, while WASP-17b has a much lower equilibrium temperature but has one of the largest atmospheric radii of known transiting planets. We discuss results from HST/WFC3 grism 1.1-1.7 micron spectroscopy of these planets during transit. We compare our integrated-light transit depths to previous IR transit photometry, and derive the 1.4-micron water absorption spectrum. We discuss implications for the atmospheric composition and structure of these hot Jupiters, and outline future observations that will further expand on these results.

Mandell, A.; Haynes, K.; Sinukoff, E.; Deming, D.; Wlikins, A.; Madhusudhan, N.; Agol, E.; Burrows, A.; Charbonneau, D.; Gilliland, R.; Knutson, H.; Ranjan, S.; Seager, S.; Showman, A.

2012-01-01

76

Transiting Exoplanet Simulations with the James Webb Space Telescope  

Science.gov (United States)

We assess the potential for JWST to characterize the atmospheres of exoplanets by using a JWST simulator developed by at GSFC. The simulator takes into account many sources of noise based on real measurements of the FGS detectors including: telescope efficiency, instrument efficiency, PRF, PSF, jitter, drift, straylight, poisson noise and flat field errors. As a follow up to Batalha et al. (JWST Whitepaper 2014), we investigate the impact of each of these parameters on the simulations of exoplanets and determine the largest sources of noise. This study is especially timely since the observing modes for the science instruments on JWST are finalized and because NASA has selected the TESS mission as an upcoming Explorer.

Batalha, N.; Mandell, A.; Kalirai, J.; Clampin, M.

2014-03-01

77

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

International Nuclear Information System (INIS)

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

78

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

OpenAIRE

Context: The Concordia base in Dome C, Antarctica, is an extremely promising site for photometric astronomy due to the 3-month long night during the Antarctic winter, favorable weather conditions, and low scintillation. Aims: The ASTEP project (Antarctic Search for Transiting ExoPlanets) is a pilot project to discover transiting planets and understand the limits of visible photometry from the Concordia site. Methods: ASTEP South is the first phase of the ASTEP project. The instrument is a fix...

Crouzet, N.; Guillot, T.; Agabi, A.; Rivet, J-p; Bondoux, E.; Challita, Z.; Fantei-caujolle, Y.; Fressin, F.; Mekarnia, D.; Schmider, F-x; Valbousquet, F.; Blazit, A.; Bonhomme, S.; Abe, L.; Daban, J-b

2009-01-01

79

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

80

DETECTION OF TRANSITING JOVIAN EXOPLANETS BY GAIA PHOTOMETRY—EXPECTED YIELD  

International Nuclear Information System (INIS)

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.

81

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

OpenAIRE

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 discerne...

Forgan, Duncan H.

2013-01-01

82

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.

Va?ko M.

2011-02-01

83

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

Science.gov (United States)

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

Griffith, Caitlin A

2014-04-28

84

A Detailed Study of the Hot n=2 Hydrogen in Transiting Exoplanet HD 189733b  

Science.gov (United States)

We propose to use Keck/HIRESr for a comprehensive study of the excited n=2 hydrogen (through H(alpha) and H(beta) transmission spectroscopy) in transiting exoplanet HD 189733b, where the first detection of H(alpha) in an exoplanet's atmosphere was made by Jensen et al. (2012). Both spectrophotometric (``transit-like") and high- resolution transmission spectroscopic methods will be used to search for all n=2 hydrogen absorption lines-H(alpha), H(beta), H(gamma), etc. We predict the first-ever detection of H(beta) in an exoplanet and an independent confirmation of H(alpha) at great statistical significance (>4sigma and 10s of sigma, respectively), and upper limits or possible detections of higher-energy transitions (depending on the amount that the detected H(alpha) is saturated). We require two separate transits to achieve this sensitivity. These measurements will allow for direct measurements of column density and probe the full hydrogen envelope via temporal variations. We will search for timing variations in the transit contact points in order to directly detect the size of the n=2 hydrogen envelope. This is only possible with the combination of time resolution, full transit coverage, and high sensitivity provided by Keck. The high spectral resolution of HIRES will allow us to make a direct comparison with it HST observations of Ly(alpha) for HD189733b.

Jensen, Adam; Redfield, Seth; Cochran, William; Endl, Michael; Koesterke, Lars; Barman, Travis; Fischer, Debra; Schwamb, Megan

2013-02-01

85

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

CERN Document Server

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

86

A Hazy Situation: Using exoplanet retrieval techniques to characterize Titan's atmosphere from a Cassini transit spectrum  

Science.gov (United States)

One of the main discoveries in exoplanet atmosphere characterization over the past several years is the dramatic role of clouds in shaping the transit spectra of close-in planets. High altitude clouds/hazes obscure molecular absorption features, leading to detrimental effects in studying transiting planet atmospheres. To investigate these effects with a "ground truth" solar system example, we utilize a transit spectrum obtained using NASA's Cassini spacecraft of Saturn's moon Titan. Titan, with its well-studied atmosphere and high-altitude hydrocarbon haze layer gives insight into how hazes affect exoplanetary transit spectra. To test how well current exoplanet atmosphere models can account for and extract information from hazy planets, we use the Bayesian CHIMERA transit spectrum model and a Markov-Chain Monte Carlo affiant-invariable ensemble technique to retrieve well-known atmospheric and planetary parameters for Titan. These include the CH4, C2H2, and CO abundances, haze scattering parameters, temperature, pressure, and gravity. We discuss how our findings compare to in situ and other Cassini remote sensing measurements, and the implications of our results for the accuracy of exoplanet retrievals for hazy bodies.

Teal, Dillon J.; Line, Michael R.; Morley, Caroline V.; Fortney, Jonathan J.

2015-01-01

87

Using near infra-red spectroscopy for characterization of transiting exoplanets  

CERN Document Server

We propose a method for observing transiting exoplanets with near-infrared high-resolution spectrometers. We aim to create a robust data analysis method for recovering atmospheric transmission spectra from transiting exoplanets over a wide wavelength range in the near infrared. By using an inverse method approach, combined with stellar models and telluric transmission spectra, the method recovers the transiting exoplanet's atmospheric transmittance at high precision over a wide wavelength range. We describe our method and have tested it by simulating observations. This method is capable of recovering transmission spectra of high enough accuracy to identify absorption features from molecules such as O2, CH4, CO2, and H2O. This accuracy is achievable for Jupiter-size exoplanetsat S/N that can be reached for 8m class telescopes using high-resolution spectrometers (R>20 000) during a single transit, and for Earth-size planets and super-Earths transiting late K or M dwarf stars at S/N reachable during observations...

Aronson, Erik; Piskunov, Nikolai

2015-01-01

88

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

CERN Document Server

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

89

C/O Ratios of Stars with Transiting Hot Jupiter Exoplanets  

Science.gov (United States)

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

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

2014-06-01

90

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

OpenAIRE

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 ...

Sandor, Zsolt

2006-01-01

91

Wideband Infrared Spectrometer for Characterization of Transiting Exoplanets with Space Telescopes  

OpenAIRE

This paper presents a conceptual design for a spectrometer designed specifically for characterizing transiting exoplanets with space-borne infrared telescopes. The design adopting cross-dispersion is intended to be simple, compact, highly stable, and has capability of simultaneous coverage over a wide wavelength region with high throughput. Typical wavelength coverage and spectral resolving power is 1-13 micron with a spectral resolving power of ~ a few hundred, respectively...

Enya, Keigo

2012-01-01

92

Towards the Albedo of an Exoplanet: MOST Satellite Observations of Bright Transiting Exoplanetary Systems  

CERN Document Server

The Canadian MOST satellite is a unique platform for observations of bright transiting exoplanetary systems. Providing nearly continuous photometric observations for up to 8 weeks, MOST can produce important observational data to help us learn about the properties of exosolar planets. We review our current observations of HD 209458, HD 189733 with implications towards the albedo and our progress towards detecting reflected light from an exoplanet.

Rowe, Jason F; Seager, Sara; Sasselov, Dimitar; Kuschnig, Rainer; Guenther, David B; Moffat, Anthony F J; Rucinski, Slavek M; Walker, Gordon A H; Weiss, Werner W

2008-01-01

93

Asteroseismology of the Transiting Exoplanet Host HD 17156 with HST FGS  

OpenAIRE

Observations conducted with the Fine Guidance Sensor on Hubble Space Telescope (HST) providing high cadence and precision time-series photometry were obtained over 10 consecutive days in December 2008 on the host star of the transiting exoplanet HD 17156b. During this time 10^12 photons (corrected for detector deadtime) were collected in which a noise level of 163 parts per million per 30 second sum resulted, thus providing excellent sensitivity to detection of the analog of...

Gilliland, Ronald L.; Mccullough, Peter R.; Nelan, Edmund P.; Brown, Timothy M.; Charbonneau, David; Nutzman, Philip; Christensen-dalsgaard, Joergen; Kjeldsen, Hans

2010-01-01

94

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.

Mahadevan S.

2011-02-01

95

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 hydrodynamcity 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.

96

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 exoplaneo 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.

97

A high dynamic-range instrument for SPICA for coronagraphic observation of exoplanets and monitoring of transiting exoplanets  

CERN Document Server

This paper, first, presents introductory reviews of the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) mission and the SPICA Coronagraph Instrument (SCI). SPICA will realize a 3m class telescope cooled to 6K in orbit. The launch of SPICA is planned to take place in FY2018. The SPICA mission provides us with a unique opportunity to make high dynamic-range observations because of its large telescope aperture, high stability, and the capability for making infrared observations from deep space. The SCI is a high dynamic-range instrument proposed for SPICA. The primary objectives for the SCI are the direct coronagraphic detection and spectroscopy of Jovian exoplanets in the infrared region, while the monitoring of transiting planets is another important target owing to the non-coronagraphic mode of the SCI. Then, recent technical progress and ideas in conceptual studies are presented, which can potentially enhance the performance of the instrument: the designs of an integral 1-dimensional binary-s...

Enya, K; Takeuchi, S; Kotani, T; Yamamuro, T

2011-01-01

98

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

CERN Document Server

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

Barnes, Rory

2013-01-01

99

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

Directory of Open Access Journals (Sweden)

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

Désert J.-M.

2011-07-01

100

The Exoplanet Orbit Database II: Updates to exoplanets.org  

OpenAIRE

The Exoplanet Orbit Database (EOD) compiles orbital, transit, host star, and other parameters of robustly detected exoplanets reported in the peer-reviewed literature. The EOD can be navigated through the Exoplanet Data Explorer (EDE) Plotter and Table, available on the World Wide Web at exoplanets.org. The EOD contains data for 1492 confirmed exoplanets as of July 2014. The EOD descends from a table in Butler et al. (2002) and the Catalog of Nearby Exoplanets (Butler et al....

Han, Eunkyu; Wang, Sharon X.; Wright, Jason T.; Feng, Y. Katherina; Zhao, Ming; Brown, Jacob I.; Hancock, Colin

2014-01-01

101

Speckle Imaging and Spectroscopy of Kepler Exo-planet Transit Candidate Stars  

Science.gov (United States)

The NASA Kepler mission was successfully launched on 6 March 2009 and has begun science operations. Commissioning tests done early on in the mission have shown that for the bright sources, 10-15 ppm relative photometry can be achieved. This level assures we will detect Earth- like transits if they are present. ``Hot Jupiter" and similar large planet candidates have already been discovered and will be discussed at the Jan. AAS meeting as well as in a special issue of Science magazine to appear near years end. The plethora of variability observed is astounding and includes a number of eclipsing binaries which appear to have Jupiter and smaller size objects as an orbiting their body. Our proposal consists of three highly related objectives: 1) To continue our highly successful speckle imaging program which is a major component of defense to weed out false positive candidate transiting planets found by Kepler and move the rest to probable or certain exo-planet detections; 2) To obtain low resolution ``discovery" type spectra for planet candidate stars in order to provide spectral type and luminosity class indicators as well as a first look triage to eliminate binaries and rapid rotators; and 3) to obtain ~1Aresolution time ordered spectra of eclipsing binaries that are exo-planet candidates in order to obtain the velocity solution for the binary star, allowing its signal to be modeled and removed from the Keck or HET exo-planet velocity search. As of this writing, Kepler has produced a list of 227 exo-planet candidates which require false positive decision tree observations. Our proposed effort performs much of the first line of defense for the mission.

Howell, Steve B.; Sherry, William; Horch, Elliott; Doyle, Laurance

2010-02-01

102

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

CERN Document Server

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

103

Exoplanet transit variability: bow shocks and winds around HD 189733b  

Science.gov (United States)

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 through 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 light curves may vary significantly and can therefore provide an insight into the structure and evolution of the stellar wind.

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

2013-12-01

104

Possible Large C/O Ratio on Several Transiting Exoplanets: Photochemical Consequences and Conceivable Origin  

Science.gov (United States)

Detailed analyses of transit and eclipse observations of extrasolar giant planets often suggest atmospheric compositions that are out of equilibrium and/or that contain a non-solar abundance of heavy elements. The departures from equilibrium are not surprising given the likely influence of transport-induced quenching of disequilibrium species on giant planets and given the large, photochemistry-inducing, ultraviolet flux incident on these close-in transiting exoplanets. What is surprising, however, is the nature of the departures from solar composition: CO typically appears to be more abundant than H2O on a wide variety of transiting exoplanets, ranging from the relatively cool GJ 436b to the warmer HD 189733b to the very hot WASP-12b. Large CO/H2O ratios are not expected from either thermochemical equilibrium or from disequilibrium chemistry in atmospheres with solar-like elemental ratios; however, they are expected for atmospheric C/O ratios that are close to 1. We use a photochemical and thermochemical kinetics and transport model to examine the influence of the atmospheric C/O ratio on the disequilibrium (and equilibrium) chemistry of the three aforementioned exoplanets. We find that the observable composition is extremely sensitive to the C/O ratio, which has some interesting consequences in relation to photochemistry and transit/eclipse observations. We discuss the implications for atmospheric composition and suggest ways in which the planets could have developed an enhanced C/O ratio during their formation and evolution. This work has been supported by the NASA Planetary Atmospheres program.

Moses, Julianne I.; Visscher, C.

2011-09-01

105

Retrieval of Atmosphere Structure and Composition of Exoplanets from Transit Spectroscopy  

Science.gov (United States)

Recent spectroscopic observations of transiting exoplanets of HD 189733b, HD 209458b, GJ 436b and GJ 1214b provide the best chance of characterizing the thermal structure and composition of their atmospheres. Here we have applied an optimal estimation retrieval architecture to fit exoplanet spectra to determine the thermal structure and composition by solving the inverse problem. The development of a suite of radiative transfer and retrieval tools for exoplanet atmospheres is explained, building upon a rapid correlated-k approximation and a retrieval algorithm extensively used in our own solar system. With these tools we discuss the best-fitting spectrum to the measurements with the best-estimated solution (i.e. the maximum a posteriori solution) for the vertical temperature structure and molecular abundances. Additionally, the contribution functions and the vertical sensitivity to the molecules are fully utilized to interpret transmission and emission spectra, probing the structure and composition of the atmosphere. Furthermore, the analysis of the cross-correlation functions permits us to quantify the uncertainties in the degeneracy between the retrieved atmospheric properties based on the current quality of the data. This sheds light on the range of diverse interpretations offered by other studies so far. It also allows us to scrutinize further atmospheric features by maximizing the capability of the current retrieval algorithm and to demonstrate the benefit of using as broad a spectral range as possible, with clear implications for the next generation of exoplanetary missions.

Lee, Jae-Min; Fletcher, L. N.; Irwin, P. G. J.

2012-01-01

106

Hubble Space Telescope search for the transit of the Earth-mass exoplanet Alpha Centauri Bb  

CERN Document Server

Results from exoplanet surveys indicate that small planets (super-Earth size and below) are abundant in our Galaxy. However, little is known about their interiors and atmospheres. There is therefore a need to find small planets transiting bright stars, which would enable a detailed characterisation of this population of objects. We present the results of a search for the transit of the Earth-mass exoplanet Alpha Centauri Bb with the Hubble Space Telescope (HST). We observed Alpha Centauri B twice in 2013 and 2014 for a total of 40 hours. We achieve a precision of 115 ppm per 6-s exposure time in a highly-saturated regime, which is found to be consistent across HST orbits. We rule out the transiting nature of Alpha Centauri Bb with the orbital parameters published in the literature at 96.6% confidence. We find in our data a single transit-like event that could be associated to another Earth-size planet in the system, on a longer period orbit. Our program demonstrates the ability of HST to obtain consistent, hi...

Demory, Brice-Olivier; Queloz, Didier; Seager, Sara; Gilliland, Ronald; Chaplin, William J; Proffitt, Charles; Gillon, Michael; Guenther, Maximilian N; Benneke, Bjoern; Dumusque, Xavier; Lovis, Christophe; Pepe, Francesco; Segransan, Damien; Triaud, Amaury; Udry, Stephane

2015-01-01

107

Toward the Detection of Exoplanet Transits with Polarimetry  

CERN Document Server

In contrast to photometric transits, whose peak signal occurs at mid-transit due to occultation of the brightest region of the disk, polarimetric transits provide a signal upon ingress and egress due to occultation of the polarized stellar limb. Limb polarization, the bright corollary to limb darkening, arises from the $90^\\circ$ scattering angle and low optical depth experienced by photons at the limb. In addition to the ratio $R_{\\rm p} / R_*$, the amplitude of a polarimetric transit is expected to be controlled by the strength and width of the stellar limb polarization profile, which depend on the scattering-to-total opacity ratio at the stellar limb. We present a short list of the systems providing the highest expected signal-to-noise ratio for detection of this effect, and we draw particular attention to HD 80606b. This planet is spin/orbit misaligned, has a three-hour ingress, and has a bright parent star, which make it an attractive target. We report on test observations of an HD 80606b ingress with th...

Wiktorowicz, Sloane J

2014-01-01

108

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

OpenAIRE

The determination of an exoplanet as rocky is critical for the assessment of planetary habitability. Observationally, the number of small-radius, transiting planets with accompanying mass measurements is insufficient for a robust determination of the transitional mass or radius. Theoretically, models predict that rocky planets can grow large enough to become gas giants when they reach ~10 Earth-masses, but the transitional mass remains unknown. Here I show how transit data, ...

Barnes, Rory

2013-01-01

109

H{alpha} ABSORPTION IN TRANSITING EXOPLANET ATMOSPHERES  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-08-01

110

Catalog of Nearby Exoplanets  

OpenAIRE

We present a catalog of nearby exoplanets, available at http://exoplanets.org and ApJ 646, 505 (published version available at the link above). It contains the 172 known low mass companions with orbits established through radial velocity and transit measurements around stars within 200 pc. We include 5 previously unpublished exoplanets orbiting the stars HD 11964, HD 66428, HD 99109, HD 107148, and HD 164922. We update orbits for 90 additional exoplanets including many whose...

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

2006-01-01

111

Venus transit 2004: Illustrating the capability of exoplanet transmission spectroscopy  

Science.gov (United States)

The transit of Venus in 2004 offered the rare possibility to remotely sense a well-known planetary atmosphere using ground-based 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. We were able to identify CO2 absorption lines in the upper Venus atmosphere. Moreover, the relative abundance of the three most abundant CO2 isotopologues could be determined. The observations resolved Venus' limb, showing Doppler-shifted absorption lines that are probably caused by high-altitude winds. We demonstrate the utility of ground-based measurements in analyzing the atmospheric constituents of a terrestrial planet atmosphere using methods that might be applied in future to terrestrial extrasolar planets.

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

2011-09-01

112

Venus transit 2004: Illustrating the capability of exoplanet transmission spectroscopy  

CERN Document Server

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

113

Observation of the full 12-hour-long transit of the exoplanet HD 80606b. Warm-Spitzer photometry and SOPHIE spectroscopy  

Science.gov (United States)

We present new observations of a transit of the 111.4-day-period exoplanet HD 80606b. Due to this long orbital period and to the orientation of the eccentric orbit (e = 0.9), HD 80606b's transits last for about 12 hours. This makes the observation of a full transit practically impossible from a given ground-based observatory. With the Spitzer Space Telescope and its IRAC camera on the post-cryogenic mission, we performed a 19-h photometric observation of HD 80606 that covers the full 2010 January 13-14 transit as well as off-transit references immediately before and after the event. We complement these photometric data by new spectroscopic observations that we simultaneously performed with SOPHIE at the Haute-Provence Observatory. This provides radial velocity measurements of the first half of the transit that was previously uncovered with spectroscopy. This new dataset allows the parameters of this singular planetary system to be significantly refined. We obtained a planet-to-star radius ratio Rp/R* = 0.1001 ± 0.0006 that is more accurate but slightly lower than the one measured from previous ground observations in the optical. We found no astrophysical interpretations able to explain this difference between optical and infrared radii; we rather favor underestimated systematic uncertainties, maybe in the ground-based composite light curve. We detected a feature in the Spitzer light curve that could be due to a stellar spot. We also found a transit timing about 20 minutes earlier than the ephemeris prediction; this could be caused by actual transit-timing variations due to an additional body in the system, or again by underestimated systematic uncertainties. The actual angle between the spin-axis of HD 80606 and the normal to the planetary orbital plane is found to be near 40° thanks to the fit of the Rossiter-McLaughlin anomaly, with a sky-projected value ? = 42° ± 8°. This allows scenarios with aligned spin-orbit to be definitively rejected. Over the twenty planetary systems with measured spin-orbit angles, a few are misaligned; this is probably the signature of two different evolution scenarios for misaligned and aligned systems, depending whether or not they experienced gravitational interaction with a third body. As in the case of HD 80606, most of the planetary systems including a massive planet are tilted; this could be the signature of a separate evolution scenario for massive planets compared with Jupiter-mass planets. Based on observations collected with the SOPHIE spectrograph on the 1.93-m telescope at the Observatoire de Haute-Provence (CNRS), France, and with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Radial velocity and photometry tables are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/516/A95

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

2010-06-01

114

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

Science.gov (United States)

We quantify the effects of refraction in transit transmission spectroscopy on spectral absorption features and on temporal variations that could be used to obtain altitude-dependent spectra for planets orbiting stars of different stellar types. We validate our model against altitude-dependent transmission spectra of the Earth from ATMOS and against lunar eclipse spectra from Pallé et al. We perform detectability studies to show the potential effects of refraction on hypothetical observations of Earth analogs with the James Webb Space Telescope NIRSPEC. Due to refraction, there will be a maximum tangent pressure level that can be probed during transit for each given planet-star system. We show that because of refraction, for an Earth-analog planet orbiting in the habitable zone of a Sun-like star only the top 0.3 bars of the atmosphere can be probed, leading to a decrease in the signal-to-noise ratio (S/N) of absorption features by 60%, while for an Earth-analog planet orbiting in the habitable zone of an M5V star it is possible to probe almost the entire atmosphere with minimal decreases in S/N. We also show that refraction can result in temporal variations in the transit transmission spectrum which may provide a way to obtain altitude-dependent spectra of exoplanet atmospheres. Additionally, the variations prior to ingress and subsequent to egress provide a way to probe pressures greater than the maximum tangent pressure that can be probed during transit. Therefore, probing the maximum range of atmospheric altitudes, and in particular the near-surface environment of an Earth-analog exoplanet, will require looking at out-of-transit refracted light in addition to the in-transit spectrum.

Misra, Amit; Meadows, Victoria; Crisp, Dave

2014-09-01

115

Bayesian mass and age estimates for transiting exoplanet host stars  

CERN Document Server

The mean density of a star transited by a planet, brown dwarf or low mass star can be accurately measured from its light curve. This measurement can be combined with other observations to estimate its mass and age by comparison with stellar models. Our aim is to calculate the posterior probability distributions for the mass and age of a star given its density, effective temperature, metallicity and luminosity. We computed a large grid of stellar models that densely sample the appropriate mass and metallicity range. The posterior probability distributions are calculated using a Markov-chain Monte-Carlo method. The method has been validated by comparison to the results of other stellar models and by applying the method to stars in eclipsing binary systems with accurately measured masses and radii. We have explored the sensitivity of our results to the assumed values of the mixing-length parameter, $\\alpha_{\\rm MLT}$, and initial helium mass fraction, Y. For a star with a mass of 0.9 solar masses and an age of 4...

Maxted, P F L; Southworth, J

2014-01-01

116

WASP-19b: THE SHORTEST PERIOD TRANSITING EXOPLANET YET DISCOVERED  

International Nuclear Information System (INIS)

We report on the discovery of a new extremely short period transiting extrasolar planet, WASP-19b. The planet has mass Mpl = 1.15 ± 0.08 MJ , radius Rpl = 1.31 ± 0.06 RJ , and orbital period P = 0.7888399 ± 0.0000008 days. Through spectroscopic analysis, we determine the host star to be a slightly super-solar metallicity ([M/H] = 0.1 ± 0.1 dex) G-dwarf with Teff = 5500 ± 100 K. In addition, we detect periodic, sinusoidal flux variations in the light curve which are used to derive a rotation period for the star of Prot = 10.5 ± 0.2 days. The relatively short stellar rotation period suggests that either WASP-19 is somewhat young (? 600 Myr old) or tidal interactions between the two bodies have caused the planet to spiral inward over its lifetime resulting in the spin-up of the star. Due to the detection of the rotation period, this system has the potential to place strong constraints on the stellar tidal quality factor, Q's, if a more precise age is determined.

117

Direct Detection of Exoplanets  

Science.gov (United States)

Direct detection of exoplanets from the ground is now within reach of existing astronomical instruments. Indeed, a few planet candidates have already been imaged and analyzed and the capability to detect (through imaging or interferometry) young, hot, Jupiter-mass planets exists. We present here an overview of what such detection methods can be expected to do in the near and far term. These methods will provide qualitatively new information about exoplanets, including spectroscopic data that will mature the study of exoplanets into a new field of comparative exoplanetary science. Spectroscopic study of exoplanet atmospheres promises to reveal aspects of atmospheric physics and chemistry as well as internal structure. Astrometric measurements will complete orbital element determinations partially known from the radial velocity surveys. We discuss the impact of these techniques, on three different timescales, corresponding to the currently available instruments, the new "Planet Finder" systems under development for 8- to 10-m telescopes, foreseen to be in operation in 5-10 years, and the more ambitious but more distant projects at the horizon of 2020.

Beuzit, J.-L.; Mouillet, D.; Oppenheimer, B. R.; Monnier, J. D.

118

Bayesian mass and age estimates for transiting exoplanet host stars  

Science.gov (United States)

Context. The mean density of a star transited by a planet, brown dwarf or low mass star can be accurately measured from its light curve. This measurement can be combined with other observations to estimate its mass and age by comparison with stellar models. Aims: Our aim is to calculate the posterior probability distributions for the mass and age of a star given its density, effective temperature, metallicity and luminosity. Methods: We computed a large grid of stellar models that densely sample the appropriate mass and metallicity range. The posterior probability distributions are calculated using a Markov-chain Monte-Carlo method. The method has been validated by comparison to the results of other stellar models and by applying the method to stars in eclipsing binary systems with accurately measured masses and radii. We have explored the sensitivity of our results to the assumed values of the mixing-length parameter, ?MLT, and initial helium mass fraction, Y. Results: For a star with a mass of 0.9 M? and an age of 4 Gyr our method recovers the mass of the star with a precision of 2% and the age to within 25% based on the density, effective temperature and metallicity predicted by a range of different stellar models. The masses of stars in eclipsing binaries are recovered to within the calculated uncertainties (typically 5%) in about 90% of cases. There is a tendency for the masses to be underestimated by about 0.1 M? for some stars with rotation periods Prot< 7 d. Conclusions: Our method makes it straightforward to determine accurately the joint posterior probability distribution for the mass and age of a star eclipsed by a planet or other dark body based on its observed properties and a state-of-the art set of stellar models. The source code for our method is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/575/A36

Maxted, P. F. L.; Serenelli, A. M.; Southworth, J.

2015-03-01

119

Transiting Planets with LSST: Assessing the Potential for LSST Exoplanet Detection  

Science.gov (United States)

Over its decade-long run, the Large Scale Synoptic Survey (LSST) will gather several hundred multi-band photometric observations of approximately ten billion stars. We demonstrate that while LSST will have a much lower cadence than most transiting planet surveys, a significant number of transiting planets will yet have sufficient photometric signal for detection. We also show that due to LSST's multiple filters and sensitivity to faint stars, LSST opens the door to detecting planets in stellar populations that have not been thoroughly searched by past surveys, including planets around red dwarfs, in star clusters, and even in the Large Magellanic Cloud. While these regimes will have very limited follow-up possibilities, LSST can provide a statistical picture of exoplanet frequencies in interesting stellar environments.

Lund, Michael; Pepper, Joshua; Stassun, Keivan; Jacklin, Savannah

2015-01-01

120

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

CERN Document Server

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

Iorio, Lorenzo

2010-01-01

121

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

CERN Document Server

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

Narita, Norio; Hirano, Teruyuki; Tamura, Motohide

2009-01-01

122

K-band transit and secondary eclipse photometry of exoplanet OGLE-TR-113b  

CERN Document Server

We present high precision K-band photometry of the transit and secondary eclipse of extrasolar planet OGLE-TR-113, using the SOFI near-infrared instrument on ESO's NTT. Data were taken in 5 second exposures over two periods of 3-4 hours, using random jitter position offsets. In this way, a relative photometric precision of ~1% per frame was achieved, avoiding systematic effects that seem to become dominant at precisions exceeding this level, and resulting in an overall accuracy of 0.1% per ~10 minutes. The observations of the transit show a flat bottom light-curve indicative of a significantly lower stellar limb-darkening at near-infrared than at optical wavelengths. The observations of the secondary eclipse result in a 3 sigma detection of emission from the exoplanet at 0.17+-0.05%. However, residual systematic errors make this detection rather tentative.

Snellen, I

2006-01-01

123

NEAR-INFRARED TRANSIT PHOTOMETRY OF THE EXOPLANET HD 149026b  

International Nuclear Information System (INIS)

The transiting exoplanet HD 149026b is an important case for theories of planet formation and planetary structure, for the planet's relatively small size has been interpreted as evidence for a highly metal-enriched composition. We present observations of four transits with the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope within a wavelength range of 1.1-2.0 ?m. Analysis of the light curve gives the most precise estimate yet of the stellar mean density, ?* = 0.497+0.042 -0.057 g cm-3. By requiring agreement between the observed stellar properties (including ?*) and stellar evolutionary models, we refine the estimate of the stellar radius: R * = 1.541+0.046 -0.042 R sun. We also find a deeper transit than has been measured at optical and mid-infrared wavelengths. Taken together, these findings imply a planetary radius of Rp = 0.813+0.027 -0.025 R Jup, which is larger than earlier estimates. Models of the planetary interior still require a metal-enriched composition, although the required degree of metal enrichment is reduced. It is also possible that the deeper NICMOS transit is caused by wavelength-dependent absorption by constituents in the planet's atmosphere, although simple model atmospheres do not predict this effect to be strong enough to account for the discrepancy. We use to account for the discrepancy. We use the four newly measured transit times to compute a refined transit ephemeris.

124

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

CERN Document Server

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

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

2009-01-01

125

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

CERN Document Server

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

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

2013-01-01

126

TRANSMISSION SPECTRUM OF EARTH AS A TRANSITING EXOPLANET FROM THE ULTRAVIOLET TO THE NEAR-INFRARED  

Energy Technology Data Exchange (ETDEWEB)

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 1000 nm. Clouds do not significantly affect this picture because refraction prevents the lowest 12.75 km 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 200 nm, ultraviolet (UV) O{sub 2} absorption increases the effective planetary radius by about 180 km, versus 27 km at 760.3 nm, and 14 km 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 UV is an interesting wavelength range for future space missions.

Betremieux, Y. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Kaltenegger, L., E-mail: betremieux@mpia.de, E-mail: kaltenegger@mpia.de [Harvard-Smithsonian Center for Astrophysics, 60 Garden street, Cambridge MA 02138 (United States)

2013-08-01

127

TRANSMISSION SPECTRUM OF EARTH AS A TRANSITING EXOPLANET FROM THE ULTRAVIOLET TO THE NEAR-INFRARED  

International Nuclear Information System (INIS)

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 1000 nm. Clouds do not significantly affect this picture because refraction prevents the lowest 12.75 km 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 200 nm, ultraviolet (UV) O2 absorption increases the effective planetary radius by about 180 km, versus 27 km at 760.3 nm, and 14 km 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 UV is an interesting wavelength range for future space missions

128

A comparison of gyrochronological and isochronal age estimates for transiting exoplanet host stars  

CERN Document Server

Previous studies suggest that tidal interactions may be responsible for discrepancies between the ages of exoplanet host stars estimated using stellar models (isochronal ages) and age estimates based on the stars' rotation periods (gyrochronological ages). We have compiled a sample of 28 transiting exoplanet host stars with measured rotation periods. We use a Bayesian Markov chain Monte Carlo method to determine the joint posterior distribution for the mass and age of each star in the sample, and extend this method to include a calculation of the posterior distribution of the gyrochronological age. The gyrochronological age ($\\tau_{\\rm gyro}$) is significantly less than the isochronal age for about half of the stars in our sample. Tidal interactions between the star and planet are a reasonable explanation for this discrepancy in some cases, but not all. The distribution of $\\tau_{\\rm gyro}$ values is evenly spread from very young ages up to a maximum value of a few Gyr. There is no clear correlation between $...

Maxted, P F L; Southworth, J

2015-01-01

129

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.

130

Recent Transits of the Super-Earth Exoplanet GJ 1214B  

Science.gov (United States)

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 observations to improve the transit ephemeris, finding P=1.5804043 +/- 0.0000005 days, and T0=2454964.94390 +/- 0.00006 BJD.

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

2001-01-01

131

Gran Telescopio Canarias OSIRIS Transiting Exoplanet Atmospheric Survey: Detection of potassium in XO-2b from narrowband spectrophotometry  

OpenAIRE

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 atmo...

Sing, David K.; De?sert, Jean-michel; Fortney, Jonathan J.; Lecavalier Des Etangs, Alain; Ballester, Gilda E.; Cepa, Jordi; Ehrenreich, David; Lo?pez-morales, Mercedes; Pont, Fre?de?ric; Shabram, Megan; Vidal-madjar, Alfred

2010-01-01

132

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

133

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

CERN Document Server

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

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

2014-01-01

134

The 2012 Transit of Venus for Cytherean Atmospheric Studies and as an Exoplanet Analog  

Science.gov (United States)

We worked to assemble as complete a dataset as possible for the Cytherean atmosphere in collaboration with Venus Express in situ and to provide an analog of spectral and total irradiance exoplanet measurements. From Haleakala, the whole transit was visible in coronal skies; our B images showed the evolution of the visibility of Venus's atmosphere and of the black-drop effect, as part of the Venus Twilight Experiment's 9 coronagraphs distributed worldwide with BVRI. We imaged the Cytherean atmosphere over two minutes before first contact, with subarcsecond resolution, with the coronagraph and a separate refractor. The IBIS imaging spectrometer at Sacramento Peak Observatory at H-alpha and carbon-dioxide also provided us high-resolution imaging. The NST of Big Bear Solar Observatory also provided high-resolution vacuum observations of the Cytherean atmosphere and black drop evolution. Our liaison with UH's Mees Solar Observatory scientists provided magneto-optical imaging at calcium and potassium. Spaceborne observations included the Solar Dynamics Observatory's AIA and HMI, and the Solar Optical Telescope (SOT) and X-ray Telescope (XRT) on Hinode, and total-solar-irradiance measurements with ACRIMSAT and SORCE/TIM, to characterize the event as an exoplanet-transit analog. Our expedition was sponsored by the Committee for Research and Exploration/National Geographic Society. Some of the funds for the carbon-dioxide filter for IBIS were provided by NASA through AAS's Small Research Grant Program. We thank Rob Lucas, Aram Friedman, and Eric Pilger '82 for assistance with Haleakala observing, Rob Ratkowski of Haleakala Amateur Astronomers for assistance with equipment and with the site, Stan Truitt for the loan of his Paramount ME, and Steve Bisque/Software Bisque for TheSky X controller. We thank Joseph Gangestad '06 of Aerospace Corp., a veteran of our 2004 expedition, for assistance at Big Bear. We thank the Lockheed Martin Solar and Astrophysics Laboratory and Hinode science and operations teams for planning and support.

Pasachoff, Jay M.; Schneider, G.; Babcock, B. A.; Lu, M.; Reardon, K. P.; Widemann, T.; Tanga, P.; Dantowitz, R.; Willson, R.; Kopp, G.; Yurchyshyn, V.; Sterling, A.; Scherrer, P.; Schou, J.; Golub, L.; Reeves, K.

2012-10-01

135

A method to identify the boundary between rocky and gaseous exoplanets from tidal theory and transit durations  

Science.gov (United States)

The determination of an exoplanet as rocky is critical for the assessment of planetary habitability. Observationally, the number of small-radius, transiting planets with accompanying mass measurements is insufficient for a robust determination of the transitional mass or radius. Theoretically, models predict that rocky planets can grow large enough to become gas giants when they reach ~10 MEarth, but the transitional mass remains unknown. Here I show how transit data, interpreted in the context of tidal theory, can reveal the critical radius that separates rocky and gaseous exoplanets. Standard tidal models predict that rocky exoplanets' orbits are tidally circularized much more rapidly than gaseous bodies', suggesting the former will tend to be found on circular orbits at larger semi-major axes than the latter. Well-sampled transits can provide a minimum eccentricity of the orbit, allowing a measurement of this differential circularization. I show that this effect should be present in the data from the Kepler spacecraft, but is not apparent. Instead, it appears that there is no evidence of tidal circularization at any planetary radius, probably because the publicly-available data, particularly the impact parameters, are not accurate enough. I also review the bias in the transit duration towards values that are smaller than that of planets on circular orbits, stressing that the azimuthal velocity of the planet determines the transit duration. The ensemble of Kepler planet candidates may be able to determine the critical radius between rocky and gaseous exoplanets, tidal dissipation as a function of planetary radius, and discriminate between tidal models.

Barnes, Rory

2015-04-01

136

New view on exoplanet transits. Transit of Venus described using three-dimensional solar atmosphere STAGGER-grid simulations  

Science.gov (United States)

Context. An important benchmark for current observational techniques and theoretical modeling of exoplanet atmospheres is the transit of Venus (ToV). Stellar activity and, in particular, convection-related surface structures, potentially cause fluctuations that can affect the transit light curves. Surface convection simulations can help interpreting the ToV as well as other transits outside our solar system. Aims: We used the realistic three-dimensional (3D) radiative hydrodynamical (RHD) simulation of the Sun from the Stagger-grid and synthetic images computed with the radiative transfer code Optim3D to predict the transit of Venus (ToV) in 2004 that was observed by the satellite ACRIMSAT. Methods: We computed intensity maps from the RHD simulation of the Sun and produced a synthetic stellar disk image as an observer would see, accounting for the center-to-limb variations. The contribution of the solar granulation was considered during the ToV. We computed the light curve and compared it to the ACRIMSAT observations as well as to light curves obtained with solar surface representations carried out using radial profiles with different limb-darkening laws. We also applied the same spherical tile imaging method as used for RHD simulation to the observations of center-to-limb solar granulation with Hinode. Results: We explain ACRIMSAT observations of 2004 ToV and show that the granulation pattern causes fluctuations in the transit light curve. We compared different limb-darkening models to the RHD simulation and evaluated the contribution of the granulation to the ToV. We showed that the granulation pattern can partially explain the observed discrepancies between models and data. Moreover, we found that the overall agreement between real and RHD solar granulation is good, either in terms of depth or ingress/egress slopes of the transit curve. This confirms that the limb-darkening and granulation pattern simulated in 3D RHD of the Sun represent well what is imaged by Hinode. In the end, we found that the contribution of the Venusean aureole during ToV is ~10-6 times less intense than the solar photosphere, and thus, accurate measurements of this phenomena are extremely challenging. Conclusions: The prospects for planet detection and characterization with transiting methods are excellent with access to large a amount of data for stars. Being able to consistently explain the data of 2004 ToV is a new step forward for 3D RHD simulations, which are becoming essential for detecting and characterizing exoplanets. They show that granulation has to be considered as an intrinsic uncertainty (as a result of stellar variability) on precise measurements of exoplanet transits of, most likely, planets with small diameters. In this context, it is mandatory to obtain a comprehensive knowledge of the host star, including a detailed study of the stellar surface convection.

Chiavassa, A.; Pere, C.; Faurobert, M.; Ricort, G.; Tanga, P.; Magic, Z.; Collet, R.; Asplund, M.

2015-04-01

137

The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b  

Science.gov (United States)

We present the results of a transcontinental campaign to observe the 2009 June 5 transit of the exoplanet HD 80606b. We report the first detection of the transit ingress, revealing the transit duration to be 11.64 ± 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibit an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. The Keck data show that the projected spin-orbit angle ? is between 32° and 87° with 68.3% confidence and between 14° and 142° with 99.73% confidence. Thus, the orbit of this planet is not only highly eccentric (e = 0.93) but is also tilted away from the equatorial plane of its parent star. A large tilt had been predicted, based on the idea that the planet's eccentric orbit was caused by the Kozai mechanism. Independently of the theory, it is worth noting that all three exoplanetary systems with known spin-orbit misalignments have massive planets on eccentric orbits, suggesting that those systems migrate through a different channel than lower mass planets on circular orbits.

Winn, Joshua N.; Howard, Andrew W.; Johnson, John Asher; Marcy, Geoffrey W.; Gazak, J. Zachary; Starkey, Donn; Ford, Eric B.; Colón, Knicole D.; Reyes, Francisco; Nortmann, Lisa; Dreizler, Stefan; Odewahn, Stephen; Welsh, William F.; Kadakia, Shimonee; Vanderbei, Robert J.; Adams, Elisabeth R.; Lockhart, Matthew; Crossfield, Ian J.; Valenti, Jeff A.; Dantowitz, Ronald; Carter, Joshua A.

2009-10-01

138

THE TRANSIT INGRESS AND THE TILTED ORBIT OF THE EXTRAORDINARILY ECCENTRIC EXOPLANET HD 80606b  

International Nuclear Information System (INIS)

We present the results of a transcontinental campaign to observe the 2009 June 5 transit of the exoplanet HD 80606b. We report the first detection of the transit ingress, revealing the transit duration to be 11.64 ± 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibit an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. The Keck data show that the projected spin-orbit angle ? is between 32 deg. and 87 deg. with 68.3% confidence and between 14 deg. and 142 deg. with 99.73% confidence. Thus, the orbit of this planet is not only highly eccentric (e = 0.93) but is also tilted away from the equatorial plane of its parent star. A large tilt had been predicted, based on the idea that the planet's eccentric orbit was caused by the Kozai mechanism. Independently of the theory, it is worth noting that all three exoplanetary systems with known spin-orbit misalignments have massive planets on eccentric orbits, suggesting that those systems migrate through a different channel than lower mass planets on circular orbits.

139

The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b  

CERN Document Server

We present the results of a pan-American campaign to observe the 2009 June 5 transit of the exoplanet HD 80606b. We report the first detection of the transit ingress, revealing the transit duration to be 11.64 +/- 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibit an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. The Keck data show that the projected spin-orbit angle is between 32-87 deg with 68.3% confidence and between 14-142 deg with 99.73% confidence. Thus the orbit of this planet is not only highly eccentric (e=0.93), but is also tilted away from the equatorial plane of its parent star. A large tilt had been predicted, based on the idea that the planet's eccentric orbit was caused by the Kozai mechanism. Independently of the theory, it is noteworthy that all 3 exoplanetary systems with known spin-orbit misalignments have massive planets on eccentric orbits, suggesting ...

Winn, Joshua N; Johnson, John Asher; Marcy, Geoffrey W; Gazak, J Zachary; Starkey, Donn; Ford, Eric B; Colon, Knicole D; Reyes, Francisco; Nortmann, Lisa; Dreizler, Stefan; Odewahn, Stephen; Welsh, William F; Kadakia, Shimonee; Vanderbei, Robert J; Adams, Elisabeth R; Lockhart, Matthew; Crossfield, Ian J; Valenti, Jeff A; Dantowitz, Ronald; Carter, Joshua A

2009-01-01

140

Observations of transits of the southern exoplanets WASP 4b and WASP 46b by using a 40 cm telescope  

Science.gov (United States)

We present photometric observations of transits of the southern exoplanets WASP 4b and WASP 46b using a 40 cm telescope. The obtained values of the orbital inclination, relative stellar radius and relative planet radius are well within the ranges of the previous solutions of the targets. The only exception is the bigger planet radius of WASP 4b that was necessary to reproduce the deeper transit observed by the TriG filter. Our data have a good time resolution and may be used for refinement of the ephemerides of WASP 4b and WASP 46b. The presented results confirmed that small telescopes can be used successfully for the study of exoplanets orbiting stars brighter than 13 mag.

Kjurkchieva, Diana; Petrov, Nikola; Popov, Velimir; Ivanov, Emil

2015-01-01

141

Molecular opacities for exoplanets.  

Science.gov (United States)

Spectroscopic observations of exoplanets are now possible by transit methods and direct emission. Spectroscopic requirements for exoplanets are reviewed based on existing measurements and model predictions for hot Jupiters and super-Earths. Molecular opacities needed to simulate astronomical observations can be obtained from laboratory measurements, ab initio calculations or a combination of the two approaches. This discussion article focuses mainly on laboratory measurements of hot molecules as needed for exoplanet spectroscopy. PMID:24664921

Bernath, Peter F

2014-04-28

142

The 0.5M$_J$ transiting exoplanet WASP-13b  

CERN Document Server

We report the discovery of WASP-13b, a low-mass $ M_p = 0.46 ^{+ 0.06}_{- 0.05} M_J$ transiting exoplanet with an orbital period of $4.35298 \\pm 0.00004$ days. The transit has a depth of 9 mmag, and although our follow-up photometry does not allow us to constrain the impact parameter well ($0 < b < 0.46$), with radius in the range $R_p \\sim 1.06 - 1.21 R_J$ the location of WASP-13b in the mass-radius plane is nevertheless consistent with H/He-dominated, irradiated, low core mass and core-free theoretical models. The G1V host star is similar to the Sun in mass (M$_{*} = 1.03^{+0.11}_ {- 0.09} M_{\\odot}$) and metallicity ([M/H]=$0.0\\pm0.2$), but is possibly older ($8.5^{+ 5.5}_{- 4.9}$ Gyr).

Skillen, I; Cameron, A Collier; Hebb, L; Simpson, E; Bouchy, F; Christian, D J; Gibson, N P; Hébrard, G; Joshi, Y C; Loeillet, B; Smalley, B; Stempels, H C; Street, R A; Udry, S; West, R G; Anderson, D R; Barros, S C C; Enoch, B; Haswell, C A; Hellier, C; Horne, K; Irwin, J; Keenan, F P; Lister, T A; Maxted, P; Mayor, M; Moutou, C; Norton, A J; Parley, N; Queloz, D; Ryans, R; Todd, I; Wheatley, P J; Wilson, D M

2009-01-01

143

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

CERN Document Server

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

144

Finding the Nearest Extrasolar Planets with the Transiting Exoplanet Survey Satellite  

Science.gov (United States)

The Transiting Exoplanet Survey Satellite (TESS) is under development for NASA's Explorers Program with a planned launch in 2017. Over a two-year mission, TESS will conduct an all-sky survey to find transiting planets around dwarf stars in the solar neighborhood using four wide-angle optical cameras. TESS will spend between 27 and 350 days covering each of several hundred thousand target stars. In order to predict its yield, we have developed a detailed simulation of the TESS mission. We model the selection of target stars and adopt a planet population from the Kepler results. Next, we calculate the photometric signal-to-noise ratio TESS will achieve, accounting for photon shot noise, instrumental artifacts, and the background from zodiacal light and unresolved stars. We will present the yields of detected planets from the latest simulations, which currently show that TESS should discover over 200 super-Earths and over 400 sub-Neptunes with host stars brighter than I=12. We will also estimate the false-positive rate from blended binary stars. These results will allow the community to prepare for follow-up observations using photometric and radial-velocity techniques.

Sullivan, Peter; Winn, Joshua N.; Dressing, Courtney D.; Charbonneau, David; Morton, Tim; Levine, Alan M.; Vanderspek, Roland Kraft; Ricker, George R.

2014-06-01

145

Asteroseismology of the Transiting Exoplanet Host HD 17156 with HST FGS  

CERN Document Server

Observations conducted with the Fine Guidance Sensor on Hubble Space Telescope (HST) providing high cadence and precision time-series photometry were obtained over 10 consecutive days in December 2008 on the host star of the transiting exoplanet HD 17156b. During this time 10^12 photons (corrected for detector deadtime) were collected in which a noise level of 163 parts per million per 30 second sum resulted, thus providing excellent sensitivity to detection of the analog of the solar 5-minute p-mode oscillations. For HD 17156 robust detection of p-modes supports determination of the stellar mean density of 0.5301 +/- 0.0044 g/cm^3 from a detailed fit to the observed frequencies of modes of degree l = 0, 1, and 2. This is the first star for which direct determination of the mean stellar density 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_star = 1.285 +/- 0...

Gilliland, Ronald L; Nelan, Edmund P; Brown, Timothy M; Charbonneau, David; Nutzman, Philip; Christensen-Dalsgaard, Joergen; Kjeldsen, Hans

2010-01-01

146

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

147

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

International Nuclear Information System (INIS)

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

148

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

Science.gov (United States)

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

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

2014-05-01

149

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

OpenAIRE

A promising method for detecting earth-sized exoplanets is the timing analysis of a known transit. The technique allows a search for variations in either the transit duration or the center induced by the perturbation of a third body, e.g. a second planet or an exomoon. By applying this method, the 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 ima...

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

2010-01-01

150

The centre-to-limb variations of solar Fraunhofer lines imprinted upon lunar eclipse spectra. Implications for exoplanet transit observations  

Science.gov (United States)

The atmospheres of exoplanets are commonly studied by observing the transit of the planet passing in front of its parent star. The obscuration of part of the stellar disk during a transit will reveal aspects of its surface structure resulting from general centre-to-limb variations (CLVs). These become apparent when forming the ratio between the stellar light in and out of transit. These phenomena can be seen particularly clearly during the progress of a penumbral lunar eclipse, where the Earth transits the solar disk and masks different regions of the solar disk as the eclipse progresses. When inferring the properties of the planetary atmosphere, it is essential that this effect originating at the star is properly accounted for. Using the data observed from the 2014-April-15 lunar eclipse with the ESPaDOnS spectrograph mounted on the Canada France Hawaii Telescope (CFHT), we have obtained for the first time a time sequence of the penumbral spectra. These penumbral spectra enable us to study the centre-to-limb variations of solar Fraunhofer lines when the Earth is transiting Sun. The Na i and Ca ii absorption features reported from previous lunar eclipse observations are demonstrated to be CLV features, which dominate the corresponding line profiles and mask possible planetary signal. Detecting atmospheric species in exoplanets via transit spectroscopy must account for the CLV effect.

Yan, F.; Fosbury, R. A. E.; Petr-Gotzens, M. G.; Zhao, G.; Pallé, E.

2015-02-01

151

High-precision ground-based observations of transiting exoplanets to detect their magnetic fields and undiscovered companions  

Science.gov (United States)

Here we present U and B band photometric light curves of several bright transiting exoplanets observed with the University of Arizona's 61''/Mont4k in order to better determine their physical parameters and search for their magnetic fields and undiscovered planetary companions. Recent studies suggest that it is possible to determine the presence and constrain the strength of a magnetic field by observing an exoplanet's bow shock. The shock would be detected via asymmetries in the UV and optical light curves, specifically if the ingress in the near-UV occurs earlier than in the optical. The size of this offset indicates the planet's magnetic field strength. In addition, our photometry, which spans multiple nights, is used to more precisely measure the radius of these exoplanets and determine any transit timing variations that could potentially indicate a nearby companion. The data are reduced via an in-house, publicly available pipeline, ExoDRPL. Our research group, AzGOE, is made primarily of undergraduate students from the University of Arizona in cooperation with the University of Arizona Astronomy Club, and gives these students the ability to take, reduce, and publish their own ground based observations.

Ryleigh Fitzpatrick, Morgan; Watson, Zachary; Zellem, Robert; Pearson, Kyle; Griffith, Caitlin Ann; AzGOE

2015-01-01

152

Optimizing exoplanet transit searches around low-mass stars with inclination constraints  

CERN Document Server

Aims. We investigate a method to increase the efficiency of a targeted exoplanet search with the transit technique by preselecting a subset of candidates from large catalogs of stars. Assuming spin-orbit alignment, this can be done by considering stars that have higher probability to be oriented nearly equator-on (inclination close to 90^{\\circ}). Methods. We use activity-rotation velocity relations for low-mass stars with a convective envelope to study the dependence of the position in the activity-vsini diagram on the stellar axis inclination. We compose a catalog of G-, K-, M-type main sequence simulated stars using isochrones, an isotropic inclination distribution and empirical relations to obtain their rotation periods and activity indexes. Then the activity - vsini diagram is filled and statistics are applied to trace the areas containing the higher ratio of stars with inclinations above 80^{\\circ}. A similar statistics is applied to stars from real catalogs with log(R'HK) and vsini data to find their p...

Herrero, E; Jordi, C; Guinan, E F; Engle, S G

2011-01-01

153

The Mid-infrared Spectrum of the Transiting Exoplanet HD 209458b  

Science.gov (United States)

We report the spectroscopic detection of mid-infrared emission from the transiting exoplanet HD 209458b. Using archive data taken with the Spitzer IRS instrument, we have determined the spectrum of HD 209458b between 7.46 and 15.25 micrometers. We have used two independent methods to determine the planet spectrum, one differential in wavelength and one absolute, and find the results are in good agreement. Over much of this spectral range, the planet spectrum is consistent with featureless thermal emission. Between 7.5 and 8.5 m, we find evidence for an unidentified spectral feature. If this spectral modulation is due to absorption, it implies that the dayside vertical temperature profile of the planetary atmosphere is not entirely isothermal. Using the IRS data, we have determined the broadband eclipse depth to be 0:00315 +/- 0:000315, implying significant redistribution of heat from the dayside to the nightside. This work required the development of improved methods for Spitzer IRS data calibration that increase the achievable absolute calibration precision and dynamic range for observations of bright point sources.

Swain, M. R.; Bouwman, J.; Akeson, R. L.; Lawler, S.; Beichman, C. A.

2008-01-01

154

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

CERN Document Server

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

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

2014-01-01

155

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

156

The Exoplanet Orbit Database  

OpenAIRE

We present a database of well determined orbital parameters of exoplanets. This database comprises spectroscopic orbital elements measured for 427 planets orbiting 363 stars from radial velocity and transit measurements as reported in the literature. We have also compiled fundamental transit parameters, stellar parameters, and the method used for the planets discovery. This Exoplanet Orbit Database includes all planets with robust, well measured orbital parameters reported i...

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

2010-01-01

157

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

Science.gov (United States)

We present seven light curves of the exoplanet system HAT-P-3, taken as part of a transit timing programme using the rapid imager to search for exoplanets instrument on the Liverpool Telescope. The light curves are analysed using a Markov chain Monte Carlo algorithm to update the parameters of the system. The inclination is found to be i = 86.75+0.22-0.21°, the planet-star radius ratio to be Rp/R* = 0.1098+0.0010-0.0012 and the stellar radius to be R* = 0.834+0.018-0.026Rsolar, consistent with previous results but with a significant improvement in the precision. Central transit times and uncertainties for each light curve are also determined, and a residual permutation algorithm is used as an independent check on the errors. The transit times are found to be consistent with a linear ephemeris, and a new ephemeris is calculated as Tc(0) = 2454856.70118 +/- 0.00018 HJD and P = 2.899738 +/- 0.000007 d. Model timing residuals are fitted to the measured timing residuals to place upper mass limits for a hypothetical perturbing planet as a function of the period ratio. These show that we have probed for planets with masses as low as 0.33 and 1.81 M? in the interior and exterior 2:1 resonances, respectively, assuming the planets are initially in circular orbits.

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

2010-01-01

158

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

159

Catalog of Nearby Exoplanets  

CERN Document Server

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

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

2006-01-01

160

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

Science.gov (United States)

Aims: We announce confirmation of Kepler-418b, one of two proposed planets in this system. This is the first confirmation of an exoplanet based primarily on the transit color signature technique. Methods: We used the Kepler public data archive combined with multicolor photometry from the Gran Telescopio de Canarias and radial velocity follow-up using FIES at the Nordic Optical Telescope for confirmation. Results: We report a confident detection of a transit color signature that can only be explained by a compact occulting body, entirely ruling out a contaminating eclipsing binary, a hierarchical triple, or a grazing eclipsing binary. Those findings are corroborated by our radial velocity measurements, which put an upper limit of ~1 MJup on the mass of Kepler-418b. We also report that the host star is significantly blended, confirming the ~10% light contamination suspected from the crowding metric in the Kepler light curve measured by the Kepler team. We report detection of an unresolved light source that contributes an additional ~30% to the target star, which would not have been detected without multicolor photometric analysis. The resulting planet-star radius ratio is 0.110 ± 0.0025, more than 25% more than the 0.087 measured by Kepler leading to a radius of 1.20 ± 0.16 RJup instead of the 0.94 RJup measured by the Kepler team. Conclusions: This is the first confirmation of an exoplanet candidate based primarily on the transit color signature, demonstrating that this technique is viable from ground for giant planets. It is particularly useful for planets with long periods such as Kepler-418b, which tend to have long transit durations. While this technique is limited to candidates with deep transits from the ground, it may be possible to confirm earth-like exoplanet candidates with a few hours of observing time with an instrument like the James Webb Space Telescope. Additionally, multicolor photometric analysis of transits can reveal unknown stellar neighbors and binary companions that do not affect the classification of the transiting object but can have a very significant effect on the perceived planetary radius. GTC g' and z' photometry and NOT-FIES spectroscopy are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/567/A14

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

2014-07-01

161

The MEarth project: an all-sky survey for transiting Earth-like exoplanets orbiting nearby M-dwarfs  

Science.gov (United States)

The MEarth project is an operational all-sky survey searching for transiting Earth-like exoplanets around 3,000 of the closest mid-to-late M-dwarfs. These will be among the best planets in their size class for atmospheric characterization using present day and near-future instruments such as HST, JWST and ground-based Extremely Large Telescopes (ELTs), by virtue of the large observational signal sizes afforded by their small and bright host stars. We present an update on the status and recent scientific results of the survey from our two observing stations: MEarth-North at Fred Lawrence Whipple Observatory, Mount Hopkins, Arizona, and MEarth-South at Cerro Tololo Inter-American Observatory, Chile. MEarth-North discovered the transiting mini-Neptune exoplanet GJ 1214b, which currently has the best-studied atmosphere of any exoplanet in its size class. In addition to searching for planets, we actively pursue stellar astrophysics topics and characterization of the target star sample using MEarth data and supplementary spectroscopic follow-up. This has included measuring astrometric parallaxes for more than 1500 nearby stars, the discovery of 6 new low-mass eclipsing binaries amenable to direct measurement of the masses and radii of their components, and rotation periods, spectral classifications, metallicities and activity indices for hundreds of stars. The MEarth light curves themselves also provide a detailed record of the photometric behavior of the target stars, which include the most favorable and interesting targets to search for small and potentially habitable planets. This will be a valuable resource for all future surveys searching for planets around these stars. All light curves gathered during the survey are made publicly available after one year.The MEarth project gratefully acknowledges funding from the David and Lucile Packard Fellowship for Science and Engineering, the National Science Foundation under grants AST-0807690, AST-1109468, and AST-1004488, and the John Templeton Foundation.

Irwin, Jonathan; Berta-Thompson, Zachory K.; Charbonneau, David; Dittmann, Jason; Newton, Elisabeth R.

2015-01-01

162

Observations of Transiting Exoplanets with the James Webb Space Telescope (JWST), Publications of the Astronomical Society of the Pacific (PASP), December 2014  

CERN Document Server

This article summarizes a workshop held on March, 2014, on the potential of the James Webb Space Telescope (JWST) to revolutionize our knowledge of the physical properties of exoplanets through transit observations. JWST's unique combination of high sensitivity and broad wavelength coverage will enable the accurate measurement of transits with high signal-to-noise. Most importantly, JWST spectroscopy will investigate planetary atmospheres to determine atomic and molecular compositions, to probe vertical and horizontal structure, and to follow dynamical evolution, i.e. exoplanet weather. JWST will sample a diverse population of planets of varying masses and densities in a wide variety of environments characterized by a range of host star masses and metallicities, orbital semi-major axes and eccentricities. A broad program of exoplanet science could use a substantial fraction of the overall JWST mission.

Beichman, Charles; Knutson, Heather; Smith, Roger; Dressing, Courtney; Latham, David; Deming, Drake; Lunine, Jonathan; Lagage, Pierre-Olivier; Sozzetti, Alessandro; Beichman, Charles; Sing, David; Kempton, Eliza; Ricker, George; Bean, Jacob; Kreidberg, Laura; Bouwman, Jeroen; Crossfield, Ian; Christiansen, Jessie; Ciardi, David; Fortney, Jonathan; Albert, Loïc; Doyon, René; Rieke, Marcia; Rieke, George; Clampin, Mark; Greenhouse, Matt; Goudfrooij, Paul; Hines, Dean; Keyes, Tony; Lee, Janice; McCullough, Peter; Robberto, Massimo; Stansberry, John; Valenti, Jeff; Deroo, Pieter D; Mandell, Avi; Ressler, Michael E; Shporer, Avi; Swain, Mark; Vasisht, Gautam; Carey, Sean; Krick, Jessica; Birkmann, Stephan; Ferruit, Pierre; Giardino, Giovanna; Greene, Tom; Howell, Steve

2014-01-01

163

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

OpenAIRE

Ground-based and space-borne observatories studying exoplanetary transits now and in the future will considerably increase the number of known exoplanets and the precision of the measured times of transit minima. Variations in the transit times can not only be used to infer the presence of additional planets, but might also provide opportunities for testing new physics in the places beyond the Solar system. In this work, we take deviation from the inverse-square law of gravi...

Xie, Yi; Deng, Xue-mei

2014-01-01

164

Determining the mass loss limit for close-in exoplanets: what can we learn from transit observations?  

Science.gov (United States)

Aims: We study the possible atmospheric mass loss from 57 known transiting exoplanets around F, G, K, and M-type stars over evolutionary timescales. For stellar wind induced mass loss studies, we estimate the position of the pressure balance boundary between Coronal Mass Ejection (CME) and stellar wind ram pressures and the planetary ionosphere pressure for non- or weakly magnetized gas giants at close orbits. Methods: The thermal mass loss of atomic hydrogen is calculated by a mass loss equation where we consider a realistic heating efficiency, a radius-scaling law and a mass loss enhancement factor due to stellar tidal forces. The model takes into account the temporal evolution of the stellar EUV flux by applying power laws for F, G, K, and M-type stars. The planetary ionopause obstacle, which is an important factor for ion pick-up escape from non- or weakly magnetized gas giants is estimated by applying empirical power-laws. Results: By assuming a realistic heating efficiency of about 10-25% we found that WASP-12b may have lost about 6-12% of its mass during its lifetime. A few transiting low density gas giants at similar orbital location, like WASP-13b, WASP-15b, CoRoT-1b or CoRoT-5b may have lost up to 1-4% of their initial mass. All other transiting exoplanets in our sample experience negligible thermal loss (?1%) during their lifetime. We found that the ionospheric pressure can balance the impinging dense stellar wind and average CME plasma flows at distances which are above the visual radius of “Hot Jupiters”, resulting in mass losses distances between 0.02-0.1 AU. Therefore, collisions of fast CMEs with hot gas giants should result in large atmospheric losses which may influence the mass evolution of gas giants with masses distance, and the related Roche lobe effect, we expect that at distances between 0.015-0.02 AU, Jupiter-class and sub-Jupiter-class exoplanets can lose several percent of their initial mass. At orbital distances ?0.015 AU, low density hot gas giants in orbits around solar type stars may even evaporate down to their coresize, while low density Neptune-class objects can lose their hydrogen envelopes at orbital distances ?0.02 AU.

Lammer, H.; Odert, P.; Leitzinger, M.; Khodachenko, M. L.; Panchenko, M.; Kulikov, Yu. N.; Zhang, T. L.; Lichtenegger, H. I. M.; Erkaev, N. V.; Wuchterl, G.; Micela, G.; Penz, T.; Biernat, H. K.; Weingrill, J.; Steller, M.; Ottacher, H.; Hasiba, J.; Hanslmeier, A.

2009-10-01

165

WASP-1b and WASP-2b: Two new transiting exoplanets detected with SuperWASP and SOPHIE  

CERN Document Server

We have detected radial-velocity variations in two objects that were identified as being likely host stars of transiting exoplanets in the 2004 SuperWASP wide-field transit survey. Using the newly-commissioned radial-velocity spectrograph SOPHIE at the Observatoire de Haute-Provence, we found that both objects exhibit reflex orbital radial-velocity variations with amplitudes characteristic of planetary-mass companions and in-phase with the photometric orbits. Line-bisector studies rule out faint blended binaries as the cause of either the radial-velocity variations or the transits. We perform preliminary spectral analyses of the host stars, which together with their radial-velocity variations and fits to the transit light curves, yield estimates of the planetary masses and radii. WASP-1b and WASP-2b have orbital periods of 2.52 and 2.15 days respectively. Given mass estimates for their F7V and K1V primaries we derive planet masses 0.80 to 0.98 and 0.81 to 0.95 times that of Jupiter respectively. WASP-1b appea...

Cameron, A C; Hébrard, G; Maxted, P; Pollacco, D; Pont, F; Skillen, I; Smalley, B; Street, R A; West, R G; Wilson, D M; Aigrain, S; Christian, D J; Clarkson, W I; Enoch, B; Evans, A; Fitzsimmons, A; Gillon, M; Haswell, C A; Hebb, L; Hellier, C; Hodgkin, S T; Horne, K; Irwin, J; Kane, S R; Keenan, F P; Loeillet, B; Lister, T A; Mayor, M; Moutou, C; Norton, A J; Osborne, J; Parley, N; Queloz, D; Ryans, R; Triaud, A; Udry, S; Wheatley, P J

2006-01-01

166

Precision Near-Infrared Photometry for Exoplanet Transit Observations. I. Ensemble Spot Photometry for an All-Sky Survey  

Science.gov (United States)

Near-IR observations are important for the detection and characterization of exoplanets using the transit technique, either in surveys of large numbers of stars or for follow-up spectroscopic observations of individual planets. In a controlled laboratory experiment, we imaged ˜104 critically sampled spots onto an Teledyne Hawaii-2RG (H2RG) detector to emulate an idealized star field. We obtained time-series photometry of up to ?24 hr duration for ensembles of ˜103 pseudostars. After rejecting correlated temporal noise caused by various disturbances, we measured a photometric performance of less than 50 ppm hr-1/2 limited only by the incident photon rate. After several hours we achieved a photon-noise-limited precision level of 10--20 ppm after averaging many independent measurements. We conclude that IR detectors such as the H2RG can make the precision measurements needed to detect the transits of terrestrial planets or to detect faint atomic or molecular spectral features in the atmospheres of transiting extrasolar planets.

Clanton, C.; Beichman, C.; Vasisht, G.; Smith, R.; Gaudi, B. S.

2012-07-01

167

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

CERN Document Server

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

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

2009-01-01

168

HEAVY-ELEMENT ENRICHMENT OF A JUPITER-MASS PROTOPLANET AS A FUNCTION OF ORBITAL LOCATION  

International Nuclear Information System (INIS)

One possible mechanism for giant planet formation is disk instability in which the planet is formed as a result of gravitational instability in the protoplanetary disk surrounding the young star. The final composition and core mass of the planet will depend on the planet's mass, environment, and the planetesimal accretion efficiency. We calculate heavy-element enrichment in a Jupiter-mass protoplanet formed by disk instability at various radial distances from the star, considering different disk masses and surface density distributions. Although the available mass for accretion increases with radial distance (a) for disk solid surface density (?) functions ? = ?0 a -? with ?5 years of planetary evolution, when the planet is extended and before gap opening and type II migration take place. The accreted mass is calculated for disk masses of 0.01, 0.05, and 0.1 M sun with ? = 1/2, 1, and 3/2. We show that a Jupiter-mass protoplanet can accrete 1-110 M + of heavy elements, depending on the disk properties. Due to the limitation on the accretion timescale, our results provide lower bounds on heavy-element enrichment. Our results can explain the large variation in heavy-element enrichment found in extrasolar giant planets. Since higher disk surface density is found to lead to larger heaity is found to lead to larger heavy-element enrichment, our model results are consistent with the correlation between heavy-element enrichment and stellar metallicity. Our calculations also suggest that Jupiter could have formed at a larger radial distance than its current location while still accreting the mass of heavy elements predicted by interior models. We conclude that in the disk instability model the final composition of a giant planet is strongly determined by its formation environment. The heavy-element abundance of a giant planet does not discriminate between its origin by either disk instability or core accretion.

169

Gran Telescopio Canarias OSIRIS transiting exoplanet atmospheric survey: detection of potassium in XO-2b from narrowband spectrophotometry  

Science.gov (United States)

We present Gran Telescopio Canarias (GTC) optical transit narrowband photometry of the hot-Jupiter exoplanet XO-2b using the OSIRIS instrument. This unique instrument has the capabilities to deliver high-cadence narrowband photometric lightcurves, allowing us to probe the atmospheric composition of hot Jupiters from the ground. The observations were taken during three transit events that cover four wavelengths at spectral resolutions near 500, necessary for observing atmospheric features, and have near-photon limited sub-mmag precisions. Precision narrowband 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 HD 209458b and HD 189733b, providing access to the majority of known transiting planets. For XO-2b, we measure planet-to-star radius contrasts of Rpl/R? = 0.10508 ± 0.00052 at 6792 Å, 0.10640 ± 0.00058 at 7582 Å, and 0.10686 ± 0.00060 at 7664.9 Å, and 0.10362 ± 0.00051 at 8839 Å. These measurements reveal significant spectral features at two wavelengths, with an absorption level of 0.067 ± 0.016% at 7664.9 Å caused by atmospheric potassium in the line core (a 4.1-? significance level), and an absorption level of 0.058 ± 0.016% at 7582 Å, (a 3.6-? significance level). When comparing our measurements to hot-Jupiter atmospheric models, we find good agreement with models that are dominated in the optical by alkali metals. This is the first evidence for potassium in an extrasolar planet, an element that has along with sodium long been supposed to be a dominant source of opacity at optical wavelengths for hot Jupiters. Based on observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, in the island of La Palma, and part of the large ESO program 182.C-2018.

Sing, D. K.; Désert, J.-M.; Fortney, J. J.; Lecavelier Des Etangs, A.; Ballester, G. E.; Cepa, J.; Ehrenreich, D.; López-Morales, M.; Pont, F.; Shabram, M.; Vidal-Madjar, A.

2011-03-01

170

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

DEFF Research Database (Denmark)

CoRoT-21, a F8IV star of magnitude V = 16 mag, was observed by the space telescope CoRoT during the Long Run 01 (LRa01) in the first winter field (constellation Monoceros) from October 2007 to March 2008. Transits were discovered during the light curve processing. Radial velocity follow-up observations, however, were performed mainly by the 10-m Keck telescope in January 2010. The companion CoRoT-21b is a Jupiter-like planet of 2.26 ± 0.33 Jupiter masses and 1.30 ± 0.14 Jupiter radii in an circular orbit of semi-major axis 0.0417 ± 0.0011 AU and an orbital period of 2.72474 ± 0.00014 days. The planetary bulk density is (1.36 ? ± ? 0.48) × 103 kg m-3, very similar to the bulk density of Jupiter, and follows an M1/3 ? R relation like Jupiter. The F8IV star is a sub-giant star of 1.29 ± 0.09 solar masses and 1.95 ± 0.2 solar radii. The star and the planet exchange extremetidal forces that will lead to orbital decay and extreme spin-up of the stellar rotation within 800 Myr if the stellar dissipation is Q?/k2? ? 107.

Pätzold, M.; Endl, M.

2012-01-01

171

Precision Near Infrared Photometry For Exoplanet Transit Observations - I : Ensemble Spot Photometry for An All-Sky Survey  

CERN Document Server

Near-IR observations are important for the detection and characterization of exoplanets using the transit technique, either in surveys of large numbers of stars or for follow-up spectroscopic observations of individual planets. In a controlled laboratory experiment, we imaged $\\sim 10^4$ critically sampled spots onto an Teledyne Hawaii-2RG (H2RG) detector to emulate an idealized star-field. We obtained time-series photometry of up to $\\simeq 24$ hr duration for ensembles of $\\sim 10^3$ pseudo-stars. After rejecting correlated temporal noise caused by various disturbances, we measured a photometric performance of $<$50 ppm-hr$^{-1/2}$ limited only by the incident photon rate. After several hours we achieve a photon-noise limited precision level of $10\\sim20$ ppm after averaging many independent measurements. We conclude that IR detectors such as the H2RG can make the precision measurements needed to detect the transits of terrestrial planets or detect faint atomic or molecular spectral features in the atmos...

Clanton, C; Vasisht, G; Smith, R; Gaudi, B S

2012-01-01

172

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

CERN Document Server

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

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

2014-01-01

173

Line-profile tomography of exoplanet transits -- II. A gas-giant planet transiting a rapidly-rotating A5 star  

CERN Document Server

Most of our knowledge of extrasolar planets rests on precise radial-velocity measurements, either for direct detection or for confirmation of the planetary origin of photometric transit signals. This has limited our exploration of the parameter space of exoplanet hosts to solar- and later-type, sharp-lined stars. Here we extend the realm of stars with known planetary companions to include hot, fast-rotating stars. Planet-like transits have previously been reported in the lightcurve obtained by the SuperWASP survey of the A5 star HD15082 (WASP-33; V=8.3, v sin i = 86 km/sec). Here we report further photometry and time-series spectroscopy through three separate transits, which we use to confirm the existence of a gas giant planet with an orbital period of 1.22d in orbit around HD15082. From the photometry and the properties of the planet signal travelling through the spectral line profiles during the transit we directly derive the size of the planet, the inclination and obliquity of its orbital plane, and its r...

Cameron, A Collier; Smalley, B; McDonald, I; Hebb, L; Andersen, J; Augusteijn, Th; Barros, S C C; Brown, D J A; Cochran, W D; Endl, M; Fossey, S J; Hartmann, M; Maxted, P F L; Pollacco, D; Skillen, I; Telting, J; Waldmann, I P; West, R G

2010-01-01

174

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

175

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

176

WASP-37b: a 1.7 MJ exoplanet transiting a metal-poor star  

CERN Document Server

We report on the discovery of WASP-37b, a transiting hot Jupiter orbiting a mv = 12.7 G2-type dwarf, with a period of 3.577471 +/- 0.00001 d, transit epoch T0 = 2455338.6189 +/- 0.0006 (HJD), and a transit duration 0.1307 +/- 0.0019 d. The planetary companion has a mass Mp = 1.696(+0.123)(-0.128) MJ and radius Rp = 1.136(+0.060){-0.051} RJ, yielding a mean density of 1.169(+0.119)(-0.152) times that of Jupiter. From a spectral analysis and comparisons with stellar models, we find the host star has M* = 0.849(+0.067)(-0.040) Msun, R* = 0.977(+0.045)(-0.042) Rsun, Teff = 5800 +/- 150 K and [Fe/H] = -0.40 +/- 0.12. WASP-37 is therefore one of the lowest metallicity stars to host a transiting planet.

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

2010-01-01

177

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

178

The Search for an Atmospheric Signature of the Transiting Exoplanet HD 149026b  

CERN Document Server

HD 149026b is a short-period, Saturn-mass planet that transits a metal-rich star. The planet's radius, determined by photometry, is remarkably small compared to other known transiting planets, with a heavy-element core that apparently comprises ~70% of the total planet mass. Time-series spectra were obtained at Keck before and during transit in order to model the Rossiter-McLaughlin effect. Here we make use of these observations to carry out a differential comparison of spectra obtained in and out of transit to search for signatures of neutral atomic lithium and potassium from the planet atmosphere. No signal was detected at the 2% level; we therefore place upper limits on the column density of these atoms.

Bozorgnia, N; McCarthy, C; Fischer, D A; Marcy, G W; Bozorgnia, Nassim; Fortney, Jonathan J.; Carthy, Chris Mc; Fischer, Debra A.; Marcy, Geoffrey W.

2006-01-01

179

Limb darkening and exoplanets: testing stellar model atmospheres and indentifying biases in transit parameters  

CERN Document Server

Limb-darkening is fundamental in determining transit lightcurve shapes, and is typically modeled by a variety of laws that parametrize the intensity profile of the star that is being transited. Confronted with a transit lightcurve, some authors fix the parameters of these laws, the so-called limb-darkening coefficients (LDCs), while others prefer to let them float in the lightcurve fitting procedure. Which of these is the best strategy, however, is still unclear, as well as how and by how much each of these can bias the retrieved transit parameters. In this work we attempt to clarify those points by first re-calculating these LDCs, comparing them to measured values from Kepler transit lightcurves using an algorithm that takes into account uncertainties in both the geometry of the transit and the parameters of the stellar host. We show there are significant departures from predicted model values, suggesting that our understanding of limb-darkening still needs to improve. Then, we show through simulations that ...

Espinoza, Néstor

2015-01-01

180

Long-lived Chaotic Orbital Evolution of Exoplanets in Mean Motion Resonances with Mutual Inclinations  

Science.gov (United States)

Mean motion resonances, in which two orbital frequencies are close to an integer multiple of each other, are common throughout the Solar System and exoplanetary systems. We present N-body simulations of resonant planets with inclined orbits and show that orbital eccentricities and inclinations can evolve chaotically for at least 10 Gyr. A wide range of behavior is possible, ranging from fast, low amplitude variations to a complete sampling of all parameter space, i.e. eccentricities reach 0.999 and inclinations 179.9 degrees. While the orbital elements evolve chaotically, at least one resonant argument librates, the traditional metric for identifying resonant behavior. This chaotic evolution is possible in the 2:1, 3:1 and 3:2 resonances, and for a range of planetary masses from lunar- to Jupiter-mass. In some cases, orbital disruption occurs after several Gyr, implying the mechanism is not rigorously stable, just long-lived relative to the main sequence lifetimes of solar type stars. We also re-examine simulations of planet-planet scattering and find that they produce planets in inclined resonances that evolve chaotically in about 0.5% of cases. Our results suggest that 1) approximate methods for identifying unstable orbital architectures may have limited applicability, 2) some short-period exoplanets may be formed during tidal circularization when the eccentricity is large, 3) those exoplanets' orbital planes may be misaligned with the host star spin axis, 4) on average, systems with resonances may be systematically younger than those without, 5) the distribution of period ratios of adjacent planets detected via transit may be skewed, and 6) potentially habitable planets may have dramatically different climatic evolution than the Earth. We show that the known systems HD 73526, HD 45364 and HD 60532 system may be in chaotically-evolving resonances. The GAIA spacecraft is capable of discovering giant planets in these types of planetary systems.

Barnes, Rory; Deitrick, Russell; Greenberg, Richard; Quinn, Thomas R.; Raymond, Sean N.

2015-01-01

181

Long-lived Chaotic Orbital Evolution of Exoplanets in Mean Motion Resonances with Mutual Inclinations  

Science.gov (United States)

We present N-body simulations of resonant planets with inclined orbits that show chaotically evolving eccentricities and inclinations that can persist for at least 10 Gyr. A wide range of behavior is possible, from fast, low amplitude variations to systems in which eccentricities reach 0.9999 and inclinations 179.°9. While the orbital elements evolve chaotically, at least one resonant argument always librates. We show that the HD 73526, HD 45364, and HD 60532 systems may be in chaotically evolving resonances. Chaotic evolution is apparent in the 2:1, 3:1, and 3:2 resonances, and for planetary masses from lunar- to Jupiter-mass. In some cases, orbital disruption occurs after several gigayears, implying the mechanism is not rigorously stable, just long-lived relative to the main sequence lifetimes of solar-type stars. Planet-planet scattering appears to yield planets in inclined resonances that evolve chaotically in about 0.5% of cases. These results suggest that (1) approximate methods for identifying unstable orbital architectures may have limited applicability, (2) the observed close-in exoplanets may be produced during epochs of high eccentricit induced by inclined resonances, (3) those exoplanets' orbital planes may be misaligned with the host star's spin axis, (4) systems with resonances may be systematically younger than those without, (5) the distribution of period ratios of adjacent planets detected via transit may be skewed due to inclined resonances, and (6) potentially habitable planets may have dramatically different climatic evolution than Earth. The Gaia spacecraft is capable of discovering giant planets in these types of orbits.

Barnes, Rory; Deitrick, Russell; Greenberg, Richard; Quinn, Thomas R.; Raymond, Sean N.

2015-03-01

182

The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b  

Science.gov (United States)

We reported the first detection of the transit ingress, revealing the transit duration to be 11.64 plus or minus 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibited an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. Thus, the orbit of this planet is not only highly eccentric but is also tilted away from the equatorial plane of its parent star. A large tilt had been predicted, based on the idea that the planet's eccentric orbit was caused by the Kozai mechanism.

Winn, Joshua N.; Howard, Andrew W.; Johnson, John A.; Marcy, Geoffrey W.; Gazak, J. Zachary; Starkey, Donn; Ford, Eric B.; Colon, Knicole D.; Reyes, Francisco; Nortmann, Lisa; Dreizler, Stefan; Odewahn, Stephen; Welsh, William F.; Kadakia, Shimonee; Vanderbei, Robert J.; Adams, Elisabeth R.; Lockhart, Matthew; Crossfield, Ian J.; Valenti, Jeff A.; Dantowitz, Ronald; Carter, Joshua A.

2009-01-01

183

Spanning the chasms: re-observing the transiting exoplanet HD 189733b  

Science.gov (United States)

We propose to validate prior detections of molecular features in published spectra of the transiting hot gas giant HD 189733b. We will observe the planet in transit and in eclipse, with the G141 grism of WFC3, using the spatial scanning technique implemented by STScI and GSFC specifically for just this type of observation. Our proposed observations will resolve the controversy surrounding the chasm between the two leading interpretations of archival NICMOS data by spanning the chasms in existing NICMOS data and WFC3 data which had been intended to resolve that controversy.

McCullough, Peter

2012-10-01

184

MOST Spacebased Photometry of the Transiting Exoplanet System HD 209458: Transit Timing to Search for Additional Planets  

CERN Document Server

We report on the measurement of transit times for the HD 209458 planetary system from photometry obtained with the MOST (Microvariability & Oscillations of STars) space telescope. Deviations from a constant orbital period can indicate the presence of additional planets in the system that are yet undetected, potentially with masses approaching an Earth mass. The MOST data sets of HD 209458 from 2004 and 2005 represent unprecedented time coverage with nearly continuous observations spanning 14 and 43 days and monitoring 3 transits and 12 consecutive transits, respectively. The transit times we obtain show no variations on three scales: (a) no long-term change in P since before 2004 at the 25 ms level, (b) no trend in transit timings during the 2005 run, and (c) no individual transit timing deviations above 80 sec level. Together with previously published transit times from Agol & Steffen (2007), this allows us to place limits on the presence of additional close-in planets in the system, in some cases do...

Miller-Ricci, E; Sasselov, D; Matthews, J M; Günther, D B; Kuschnig, R; Moffat, A F J; Rucinski, S M; Walker, G A H; Weiss, W W

2008-01-01

185

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

CERN Document Server

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

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

2013-01-01

186

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

Science.gov (United States)

CoRoT-21, a F8IV star of magnitude V = 16 mag, was observed by the space telescope CoRoT during the Long Run 01 (LRa01) in the first winter field (constellation Monoceros) from October 2007 to March 2008. Transits were discovered during the light curve processing. Radial velocity follow-up observations, however, were performed mainly by the 10-m Keck telescope in January 2010. The companion CoRoT-21b is a Jupiter-like planet of 2.26 ± 0.33 Jupiter masses and 1.30 ± 0.14 Jupiter radii in an circular orbit of semi-major axis 0.0417 ± 0.0011 AU and an orbital period of 2.72474 ± 0.00014 days. The planetary bulk density is (1.36 ± 0.48) × 103 kg m-3, very similar to the bulk density of Jupiter, and follows an M1/3 - R relation like Jupiter. The F8IV star is a sub-giant star of 1.29 ± 0.09 solar masses and 1.95 ± 0.2 solar radii. The star and the planet exchange extremetidal forces that will lead to orbital decay and extreme spin-up of the stellar rotation within 800 Myr if the stellar dissipation is Q?/k2? ? 107. The CoRoT space mission, launched on December 27th 2006, has been developed and is operated by CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany and Spain.

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

2012-09-01

187

MOST Spacebased Photometry of the Transiting Exoplanet System HD 189733: Precise Timing Measurements for Transits Across an Active Star  

CERN Document Server

We have measured transit times for HD 189733b passing in front of its bright (V = 7.67) chromospherically active and spotted parent star. Nearly continuous broadband optical photometry of this system was obtained with the MOST (Microvariability & Oscillations of STars) space telescope during 21 days in August 2006, monitoring 10 consecutive transits. We have used these data to search for deviations from a constant orbital period which can indicate the presence of additional planets in the system that are as yet undetected by Doppler searches. There are no transit timing variations above the level of ${\\pm}45$ s, ruling out super-Earths (of masses $1 - 4 M_{\\earth}$) in the 1:2 and 2:3 inner resonances and planets of 20 $M_{\\earth}$ in the 2:1 outer resonance of the known planet. We also discuss complications in measuring transit times for a planet that transits an active star with large star spots, and how the transits can help constrain and test spot models. This has implications for the large number of ...

Miller-Ricci, E; Sasselov, D; Matthews, J M; Kuschnig, R; Croll, B; Günther, D B; Moffat, A F J; Rucinski, S M; Walker, G A H; Weiss, W W

2008-01-01

188

Exoplanet Orbit Database. II. Updates to Exoplanets.org  

Science.gov (United States)

The Exoplanet Orbit Database (EOD) compiles orbital, transit, host star, and other parameters of robustly-detected exoplanets reported in the peer-reviewed literature. The EOD can be navigated through the Exoplanet Data Explorer (EDE) plotter and table, available on the World Wide Web at http://exoplanets.org. The EOD contains data for 1492 confirmed exoplanets as of 2014 July. The EOD descends from a table provided by Butler and coworkers in 2002 and the Catalog of Nearby Exoplanets (Butler and coworkers in 2006), and the first complete documentation for the EOD and the EDE was presented by Wright and coworkers in 2011. In this work, we describe our work since then. We have expanded the scope of the EOD to include secondary eclipse parameters and asymmetric uncertainties and expanded the EDE to include the sample of over 3000 Kepler Objects of Interest (KOIs) and other real planets without good orbital parameters (such as many of those detected by microlensing and imaging). Users can download the latest version of the entire EOD as a single comma separated value file from the front page of http://exoplanets.org.

Han, Eunkyu; Wang, Sharon X.; Wright, Jason T.; Feng, Y. Katherina; Zhao, Ming; Fakhouri, Onsi; Brown, Jacob I.; Hancock, Colin

2014-10-01

189

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

190

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  

CERN Document Server

We announce the discovery of the transiting planet CoRoT-13b. Ground based follow-up in CFHT and IAC80 confirmed CoRoT's observations. The mass of the planet was measured with the HARPS spectrograph and the properties of the host star were obtained analyzing HIRES spectra from the Keck telescope. It is a hot Jupiter-like planet with an orbital period of 4.04 days, 1.3 Jupiter masses, 0.9 Jupiter radii, and a density of 2.34 g cm-3. It orbits a G0V star with Teff=5945K, M*=1.09 Msun, R*=1.01 Rsun, solar metallicity, a lithium content of +1.45 dex, and an estimated age between 0.12 and 3.15 Gyr. The lithium abundance of the star is consistent with its effective temperature, activity level, and age range derived from the stellar analysis. The density of the planet is extreme for its mass. It implies the existence of an amount of heavy elements with a mass between about 140 and 300 Mearth.

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

2010-01-01

191

Fluctuations and Flares in the Ultraviolet Line Emission of Cool Stars: Implications for Exoplanet Transit Observations  

OpenAIRE

Variations in stellar flux can potentially overwhelm the photometric signal of a transiting planet. Such variability has not previously been well-characterized in the ultraviolet lines used to probe the inflated atmospheres surrounding hot Jupiters. Therefore, we surveyed 38 F-M stars for intensity variations in four narrow spectroscopic bands: two enclosing strong lines from species known to inhabit hot Jupiter atmospheres, CII $\\lambda\\lambda$1334,1335 and SiIII $\\lambda$1...

Loyd, R. O. Parke; France, Kevin

2014-01-01

192

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

Science.gov (United States)

We report an analysis of transit spectroscopy of the extrasolar planets WASP-12 b, WASP-17 b, and WASP-19 b using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). We analyze the data for a single transit for each planet using a strategy similar, in certain aspects, to the techniques used by Berta et al., but we extend their methodology to allow us to correct for channel- or wavelength-dependent instrumental effects by utilizing the band-integrated time series and measurements of the drift of the spectrum on the detector over time. We achieve almost photon-limited results for individual spectral bins, but the uncertainties in the transit depth for the band-integrated data are exacerbated by the uneven sampling of the light curve imposed by the orbital phasing of HST's observations. Our final transit spectra for all three objects are consistent with the presence of a broad absorption feature at 1.4 microns most likely due to water. However, the amplitude of the absorption is less than that expected based on previous observations with Spitzer, possibly due to hazes absorbing in the NIR or non-solar compositions. The degeneracy of models with different compositions and temperature structures combined with the low amplitude of any features in the data preclude our ability to place unambiguous constraints on the atmospheric composition without additional observations with WFC3 to improve the signal-to-noise ratio and/or a comprehensive multi-wavelength analysis. Key words: planetary systems - techniques: photometric - techniques: spectroscopic

Mandell, Avi M.; Haynes, Korey; Sinukoff, Evan; Madhusudhan, Nikku; Burrows, Adam; Deming, Drake

2013-01-01

193

Experimental evidence for a phase transition in magnesium oxide at exoplanet pressures  

Science.gov (United States)

Magnesium oxide is an important component of the Earth's mantle and has been extensively studied at pressures and temperatures relevant to Earth. However, much less is known about the behaviour of this oxide under conditions likely to occur in extrasolar planets with masses up to 10 times that of Earth, termed super-Earths, where pressures can exceed 1,000GPa (10 million atmospheres). Magnesium oxide is expected to change from a rocksalt crystal structure (B1) to a caesium chloride (B2) structure at pressures of about 400-600GPa (refs , ). Whereas no structural transformation was observed in static compression experiments up to 250GPa (ref. ), evidence for a solid-solid phase transition was obtained in shockwave experiments above 400GPa and 9,000K (ref. ), albeit no structural measurements were made. As a result, the properties and the structure of MgO under conditions relevant to super-Earths and large planets are unknown. Here we present dynamic X-ray diffraction measurements of ramp-compressed magnesium oxide. We show that a solid-solid phase transition, consistent with a transformation to the B2 structure, occurs near 600GPa. On further compression, this structure remains stable to 900GPa. Our results provide an experimental benchmark to the equations of state and transition pressure of magnesium oxide, and may help constrain mantle viscosity and convection in the deep mantle of extrasolar super-Earths.

Coppari, F.; Smith, R. F.; Eggert, J. H.; Wang, J.; Rygg, J. R.; Lazicki, A.; Hawreliak, J. A.; Collins, G. W.; Duffy, T. S.

2013-11-01

194

Three WASP-South transiting exoplanets: WASP-74b, WASP-83b & WASP-89b  

CERN Document Server

We report the discovery of three new transiting hot Jupiters by WASP-South together with the TRAPPIST photometer and the Euler/CORALIE spectrograph. WASP-74b orbits a star of V = 9.7, making it one of the brighter systems accessible to Southern telescopes. It is a 0.95 M_Jup planet with a moderately bloated radius of 1.5 R_Jup in a 2-d orbit around a slightly evolved F9 star. WASP-83b is a Saturn-mass planet at 0.3 M_Jup with a radius of 1.0 R_Jup. It is in a 5-d orbit around a fainter (V = 12.9) G8 star. WASP-89b is a 6 M_Jup planet in a 3-d orbit with an eccentricity of e = 0.2. It is thus similar to massive, eccentric planets such as XO-3b and HAT-P-2b, except that those planets orbit F stars whereas WASP-89 is a K star. The V = 13.1 host star is magnetically active, showing a rotation period of 20.2 d, while star spots are visible in the transits. There are indications that the planet's orbit is aligned with the stellar spin. WASP-89 is a good target for an extensive study of transits of star spots.

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

2014-01-01

195

Line-profile tomography of exoplanet transits I: The Doppler shadow of HD 189733b  

CERN Document Server

We present a direct method for isolating the component of the starlight blocked by a planet as it transits its host star, and apply it to spectra of the bright transiting planet HD 189733b. We model the global shape of the stellar cross-correlation function as the convolution of a limb-darkened rotation profile and a gaussian representing the Doppler core of the average photospheric line profile. The light blocked by the planet during the transit is a gaussian of the same intrinsic width, whose trajectory across the line profile yields a precise measure of the misalignment angle and an independent measure of v sin I. We show that even when v sin I is less than the width of the intrinsic line profile, the travelling Doppler "shadow" cast by the planet creates an identifiable distortion in the line profiles which is amenable to direct modelling. Direct measurement of the trajectory of the missing starlight yields self-consistent measures of the projected stellar rotation rate, the intrinsic width of the mean lo...

Cameron, A Collier; Miller, G R M; Triaud, A H M J; Queloz, D

2009-01-01

196

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

International Nuclear Information System (INIS)

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

197

Evolution of Exoplanets and their Parent Stars  

OpenAIRE

Studying exoplanets with their parent stars is crucial to understand their population, formation and history. We review some of the key questions regarding their evolution with particular emphasis on giant gaseous exoplanets orbiting close to solar-type stars. For masses above that of Saturn, transiting exoplanets have large radii indicative of the presence of a massive hydrogen-helium envelope. Theoretical models show that this envelope progressively cools and contracts wit...

Guillot, Tristan; Lin, Douglas; Morel, Pierre; Havel, Mathieu; Parmentier, Vivien

2014-01-01

198

Fluctuations and Flares in the Ultraviolet Line Emission of Cool Stars: Implications for Exoplanet Transit Observations  

Science.gov (United States)

Variations in stellar flux can potentially overwhelm the photometric signal of a transiting planet. Such variability has not previously been well-characterized in the ultraviolet lines used to probe the inflated atmospheres surrounding hot Jupiters. Therefore, we surveyed 38 F-M stars for intensity variations in four narrow spectroscopic bands: two enclosing strong lines from species known to inhabit hot Jupiter atmospheres, C II ??1334, 1335 and Si III ?1206 one enclosing Si IV ??1393, 1402; and 36.5 Å of interspersed continuum. For each star/band combination, we generated 60 s cadence lightcurves from archival Hubble Space Telescope Cosmic Origins Spectrograph and Space Telescope Imaging Spectrograph time-tagged photon data. Within these lightcurves, we characterized flares and stochastic fluctuations as separate forms of variability. Flares: we used a cross-correlation approach to detect 116 flares. These events occur in the time-series an average of once per 2.5 hr, over 50% last 4 minutes or less, and most produce the strongest response in Si IV. If the flare occurred during a transit measurement integrated for 60 minutes, 90/116 would destroy the signal of an Earth, 27/116 Neptune, and 7/116 Jupiter, with the upward bias in flux ranging from 1% to 109% of quiescent levels. Fluctuations: photon noise and underlying stellar fluctuations produce scatter in the quiescent data. We model the stellar fluctuations as Gaussian white noise with standard deviation ? x . Maximum likelihood values of ? x range from 1% to 41% for 60 s measurements. These values suggest that many cool stars will only permit a transit detection to high confidence in ultraviolet resonance lines if the radius of the occulting disk is gsim1 RJ . However, for some M dwarfs this limit can be as low as several R ?.

Loyd, R. O. Parke; France, Kevin

2014-03-01

199

Radial velocity follow-up of CoRoT transiting exoplanets  

OpenAIRE

We report on the results from the radial-velocity follow-up program performed to establish the planetary nature and to characterize the transiting candidates discovered by the space mission CoRoT. We use the SOPHIE at OHP, HARPS at ESO and the HIRES at Keck spectrographs to collect spectra and high- precision radial velocity (RV) measurements for several dozens dif- ferent candidates from CoRoT. We have measured the Rossiter- McLaughlin effect of several confirmed planets, e...

Deleuil M.; Moutou C.; Bouchy F.; Hatzes A.; Santerne A.; Endl M.

2011-01-01

200

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

OpenAIRE

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...

Turner, Jake D.; Smart, Brianna M.; 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.

2012-01-01

201

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

CERN Document Server

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

Misra, Amit; Crisp, Dave

2014-01-01

202

Colour-magnitude diagrams of transiting Exoplanets - I. Systems with parallaxes  

Science.gov (United States)

Broad-band flux measurements centred around [3.6 ?m] and [4.5 ?m] obtained with Spitzer during the occultation of seven extrasolar planets by their host stars have been combined with parallax measurements to compute the absolute magnitudes of these planets. Those measurements are arranged in two colour-magnitude diagrams. Because most of the targets have sizes and temperatures similar to brown dwarfs, they can be compared to one another. In principle, this should permit inferences about exoatmospheres based on knowledge acquired by decades of observations of field brown dwarfs and ultracool stars' atmospheres. Such diagrams can assemble all measurements gathered so far and will provide help in the preparation of new observational programmes. In most cases, planets and brown dwarfs follow similar sequences. HD 2094589b and GJ 436b are found to be outliers, so is the night side of HD 189733b. The photometric variability associated with the orbital phase of HD 189733b is particularly revealing. The planet exhibits what appears like a spectral type and chemical transition between its day and night sides: HD 189733b straddles the L-T spectral class transition, which would imply different cloud coverage on each hemisphere. Methane absorption could be absent at its hotspot but present over the rest of the planet.

Triaud, Amaury H. M. J.

2014-03-01

203

STRESS - STEREO TRansiting Exoplanet and Stellar Survey - I : Introduction and Data Pipeline  

CERN Document Server

The Solar TErrestrial RElations Observatory - \\emph{STEREO}, is a system of two identical spacecraft in Heliocentric Earth orbit. We use the two Heliospheric Imagers (HI), which are wide angle imagers with multi-baffle systems to do high precision stellar photometry in order to search for exoplanetary transits and understand stellar variables. The large cadence (40 min for HI-1 and 2 hrs for HI-2), high precision, wide magnitude range (\\emph{R} mag - 4 to 12) and broad sky coverage (nearly 20 percent just for HI-1A and 60 per cent of the sky in the zodiacal region for all the instruments combined) of this instrument marks this in a space left largely devoid by other current projects. In this paper, we describe the semi-automated pipeline devised for the reduction of this data, some of the interesting characteristics of the data obtained, data analysis methods used along with some early results.

Sangaralingam, Vinothini

2011-01-01

204

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

205

Fluctuations and Flares in the Ultraviolet Line Emission of Cool Stars: Implications for Exoplanet Transit Observations  

CERN Document Server

Variations in stellar flux can potentially overwhelm the photometric signal of a transiting planet. Such variability has not previously been well-characterized in the ultraviolet lines used to probe the inflated atmospheres surrounding hot Jupiters. Therefore, we surveyed 38 F-M stars for intensity variations in four narrow spectroscopic bands: two enclosing strong lines from species known to inhabit hot Jupiter atmospheres, CII $\\lambda\\lambda$1334,1335 and SiIII $\\lambda$1206; one enclosing SiIV $\\lambda\\lambda$1393,1402; and 36.5 \\AA\\ of interspersed continuum. For each star/band combination, we generated 60 s cadence lightcurves from archival HST COS and STIS time-tagged photon data. Within these lightcurves, we characterized flares and stochastic fluctuations as separate forms of variability. Flares: We used a cross-correlation approach to detect 116 flares. These events occur in the time-series an average of once per 2.5 h, over 50% last 4 min or less, and most produce the strongest response in SiIV. If...

Loyd, R O Parke

2014-01-01

206

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

International Nuclear Information System (INIS)

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

207

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

CERN Document Server

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

208

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.

Damiani C.

2011-02-01

209

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

CERN Document Server

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

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

2010-01-01

210

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

211

ketu: Exoplanet candidate search code  

Science.gov (United States)

ketu, written in Python, searches K2 light curves for evidence of exoplanets; the code simultaneously fits for systematic effects caused by small (few-pixel) drifts in the telescope pointing and other spacecraft issues and the transit signals of interest. Though more computationally expensive than standard search algorithms, it can be efficiently implemented and used to discover transit signals.

Foreman-Mackey, Daniel

2015-02-01

212

The Qatar Exoplanet Survey  

Science.gov (United States)

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

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

2013-12-01

213

The Qatar Exoplanet Survey  

CERN Document Server

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

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

2014-01-01

214

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 convergt accelerates the convergence of Markov chains that employ the Metropolis random walk sampler. The electronic supplement contains light-curve files.

215

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

International Nuclear Information System (INIS)

Three-dimensional (3D) dynamical models of hot Jupiter atmospheres predict very strong wind speeds. For tidally locked hot Jupiters, winds at high altitude in the planet's atmosphere advect heat from the day side to the cooler night side of the planet. Net wind speeds on the order of 1-10 km s–1 directed towards the night side of the planet are predicted at mbar pressures, which is the approximate pressure level probed by transmission spectroscopy. These winds should result in an observed blueshift of spectral lines in transmission on the order of the wind speed. Indeed, Snellen et al. recently observed a 2 ± 1 km s–1 blueshift of CO transmission features for HD 209458b, which has been interpreted as a detection of the day-to-night (substellar to anti-stellar) winds that have been predicted by 3D atmospheric dynamics modeling. Here, we present the results of a coupled 3D atmospheric dynamics and transmission spectrum model, which predicts the Doppler-shifted spectrum of a hot Jupiter during transit resulting from winds in the planet's atmosphere. We explore four different models for the hot Jupiter atmosphere using different prescriptions for atmospheric drag via interaction with planetary magnetic fields. We find that models with no magnetic drag produce net Doppler blueshifts in the transmission spectrum of ?2 km s–1 and that lower Doppler shifts of ?1 km s–1 are found for the higher drag cases, results consiser 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.

216

Stellar Diameters and Temperatures VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs  

CERN Document Server

We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limb-darkened angular diameters to be theta_LD = 0.3848 +/- 0.0055 and 0.2254 +/- 0.0072 milliarcsec for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two transiting exoplanet systems where detection of the respective planetary companion's orbital motion from high resolution spectroscopy has revealed absolute masses for both star and planet. We use our new measurements together with the orbital information from radial velocity and photometric time series data, Hipparcos distances, and newly measured bolometric fluxes to determine the stellar effective temperatures (T_eff = 4875 +/- 43, 6093 +/- 103 K), stellar linear radii (R_* = 0.805 +/- 0.016, 1.203 +/- 0.061 R_sun), mean stellar densities (rho_* = 1.62 +/- 0.11, 0.58 +/- 0.14 rho_sun), planetary radii (R_p = 1.216 +/- 0.024, 1.451 +/- 0.074 R_Jup), and mean ...

Boyajian, Tabetha; Feiden, Gregory A; Huber, Daniel; Basu, Sarbani; Demarque, Pierre; Fischer, Debra A; Schaefer, Gail; Mann, Andrew W; White, Timothy R; Maestro, Vicente; Brewer, John; Lamell, C Brooke; Spada, Federico; López-Morales, Mercedes; Ireland, Michael; Farrington, Chris; van Belle, Gerard T; Kane, Stephen R; Jones, Jeremy; Brummelaar, Theo A ten; Ciardi, David R; McAlister, Harold A; Ridgway, Stephen; Goldfinger, P J; Turner, Nils H; Sturmann, Laszlo

2014-01-01

217

SOPHIE velocimetry of Kepler transit candidates. XII. KOI-1257 b: a highly eccentric three-month period transiting exoplanet  

Science.gov (United States)

In this paper we report a new transiting warm giant planet: KOI-1257 b. It was first detected in photometry as a planet-candidate by the Kepler space telescope and then validated thanks to a radial velocity follow-up with the SOPHIE spectrograph. It orbits its host star with a period of 86.647661 d ± 3 s and a high eccentricity of 0.772 ± 0.045. The planet transits the main star of a metal-rich, relatively old binary system with stars of mass of 0.99 ± 0.05 M? and 0.70 ± 0.07 M? for the primary and secondary, respectively. This binary system is constrained thanks to a self-consistent modelling of the Kepler transit light curve, the SOPHIE radial velocities, line bisector and full-width half maximum (FWHM) variations, and the spectral energy distribution. However, future observations are needed to confirm it. The PASTIS fully-Bayesian software was used to validate the nature of the planet and to determine which star of the binary system is the transit host. By accounting for the dilution from the binary both in photometry and in radial velocity, we find that the planet has a mass of 1.45 ± 0.35 M? , and a radius of 0.94 ± 0.12 R? , and thus a bulk density of 2.1 ± 1.2 g cm-3. The planet has an equilibrium temperature of 511 ± 50 K, making it one of the few known members of the warm-Jupiter population. The HARPS-N spectrograph was also used to observe a transit of KOI-1257 b, simultaneously with a joint amateur and professional photometric follow-up, with the aim of constraining the orbital obliquity of the planet. However, the Rossiter-McLaughlin effect was not clearly detected, resulting in poor constraints on the orbital obliquity of the planet. Based on observations made with SOPHIE on the 1.93 m telescope at Observatoire de Haute-Provence (CNRS), France, and with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Part of the observations were made with the IAC80 operated on the Spanish Observatorio del Teide of the Instituto de Astrofísica de Canarias.Appendices are available in electronic form at http://www.aanda.orgFull Tables C.5-C.7 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/571/A37

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

2014-11-01

218

Exoplanet habitability.  

Science.gov (United States)

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. PMID:23641111

Seager, Sara

2013-05-01

219

The Exoplanet Orbit Database II: Updates to exoplanets.org  

CERN Document Server

The Exoplanet Orbit Database (EOD) compiles orbital, transit, host star, and other parameters of robustly detected exoplanets reported in the peer-reviewed literature. The EOD can be navigated through the Exoplanet Data Explorer (EDE) Plotter and Table, available on the World Wide Web at exoplanets.org. The EOD contains data for 1492 confirmed exoplanets as of July 2014. The EOD descends from a table in Butler et al. (2002) and the Catalog of Nearby Exoplanets (Butler et al. 2006), and the first complete documentation for the EOD and the EDE was presented in Wright et al. (2011). In this work, we describe our work since then. We have expanded the scope of the EOD to include secondary eclipse parameters, asymmetric uncertainties, and expanded the EDE to include the sample of over 3000 Kepler Objects of Interest (KOIs), and other real planets without good orbital parameters (such as many of those detected by microlensing and imaging). Users can download the latest version of the entire EOD as a single comma sep...

Han, Eunkyu; Wright, Jason T; Feng, Y Katherina; Zhao, Ming; Brown, Jacob I; Hancock, Colin

2014-01-01

220

Notes on exoplanets  

International Nuclear Information System (INIS)

Our knowledge about exoplanets evolves rapidly. Here I give a short overview of some aspects of the exoplanet research and I also introduce shortly the reader to the Hungarian activities in the exoplanet field.

221

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

Science.gov (United States)

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

Xie, Yi; Deng, Xue-Mei

2014-02-01

222

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

CERN Document Server

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

Xie, Yi

2014-01-01

223

Exoplanet Chemistry  

OpenAIRE

The terrestrial and gas-giant planets in our solar system may represent some prototypes for planets around other stars; the exoplanets because most stars have similar overall elemental abundances as our sun. The solar system planets represent at least four chemical planet types, depending on the phases that make them: Terrestrial-like planets made of rock (metal plus silicates), Plutonian planets made of rock and ice, Neptunian giant planets of rocky, icy with low H and He c...

Lodders, Katharina

2009-01-01

224

Water in exoplanets.  

Science.gov (United States)

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. PMID:22547242

Tinetti, Giovanna; Tennyson, Jonathan; Griffith, Caitlin A; Waldmann, Ingo

2012-06-13

225

Stellar diameters and temperatures - VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs  

Science.gov (United States)

We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limb-darkened angular diameters to be ?LD = 0.3848 ± 0.0055 and 0.2254 ± 0.0072 mas for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two transiting exoplanet systems where detection of the respective planetary companion's orbital motion from high-resolution spectroscopy has revealed absolute masses for both star and planet. We use our new measurements together with the orbital information from radial velocity and photometric time series data, Hipparcos distances, and newly measured bolometric fluxes to determine the stellar effective temperatures (Teff = 4875 ± 43, 6092 ± 103 K), stellar linear radii (R* = 0.805 ± 0.016, 1.203 ± 0.061 R?), mean stellar densities (?* = 1.62 ± 0.11, 0.58 ± 0.14 ??), planetary radii (Rp = 1.216 ± 0.024, 1.451 ± 0.074 RJup), and mean planetary densities (?p = 0.605 ± 0.029, 0.196 ± 0.033 ?Jup) for HD 189733b and HD 209458b, respectively. The stellar parameters for HD 209458, an F9 dwarf, are consistent with indirect estimates derived from spectroscopic and evolutionary modelling. However, we find that models are unable to reproduce the observational results for the K2 dwarf, HD 189733. We show that, for stellar evolutionary models to match the observed stellar properties of HD 189733, adjustments lowering the solar-calibrated mixing-length parameter to ?MLT =1.34 need to be employed.

Boyajian, Tabetha; von Braun, Kaspar; Feiden, Gregory A.; Huber, Daniel; Basu, Sarbani; Demarque, Pierre; Fischer, Debra A.; Schaefer, Gail; Mann, Andrew W.; White, Timothy R.; Maestro, Vicente; Brewer, John; Lamell, C. Brooke; Spada, Federico; López-Morales, Mercedes; Ireland, Michael; Farrington, Chris; van Belle, Gerard T.; Kane, Stephen R.; Jones, Jeremy; ten Brummelaar, Theo A.; Ciardi, David R.; McAlister, Harold A.; Ridgway, Stephen; Goldfinger, P. J.; Turner, Nils H.; Sturmann, Laszlo

2015-02-01

226

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

227

Formation, evolution and multiplicity of brown dwarfs and giant exoplanets  

CERN Document Server

This proceeding summarises the talk of the awardee of the Spanish Astronomical Society award to the the best Spanish thesis in Astronomy and Astrophysics in the two-year period 2006-2007. The thesis required a tremendous observational effort and covered many different topics related to brown dwarfs and exoplanets, such as the study of the mass function in the substellar domain of the young sigma Orionis cluster down to a few Jupiter masses, the relation between the cluster stellar and substellar populations, the accretion discs in cluster brown dwarfs, the frequency of very low-mass companions to nearby young stars at intermediate and wide separations, or the detectability of Earth-like planets in habitable zones around ultracool (L- and T-type) dwarfs in the solar neighbourhood.

Caballero, Jose A

2008-01-01

228

Analysis of Secondary Eclipse Observations of Exoplanet WASP-34b  

Science.gov (United States)

WASP-34b is a short-period exoplanet with a mass of 0.59 +/- 0.01 Jupiter masses orbiting a sun-like star with a period of 4.3177 days and an eccentricity of 0.038 +/- 0.012 (Smalley, 2010). We observed WASP-34b using the 3.6 and 4.5 micron channels of the Infrared Array Camera aboard the Spitzer Space Telescope in 2010 (Program 60003). We present eclipse-depth measurements, estimates of infrared brightness temperatures, and refine the orbit using our secondary eclipse measurements. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

Challener, Ryan; Harrington, Joseph; Garland, Justin; Cubillos, Patricio; Blecic, Jasmina; Smalley, Barry

2014-11-01

229

The Transiting Exoplanet Host Star GJ 436: A Test of Stellar Evolution Models in the Lower Main Sequence, and Revised Planetary Parameters  

Science.gov (United States)

Knowledge of the stellar parameters for the parent stars of transiting exoplanets is a prerequisite for establishing the planet properties themselves, and often relies on stellar evolution models. GJ 436, which is orbited by a transiting Neptune-mass object, presents a difficult case because it is an M dwarf. Stellar models in this mass regime are not as reliable as for higher mass stars, and tend to underestimate the radius. Here we use constraints from published transit light curve solutions for GJ 436 along with other spectroscopic quantities to show how the models can still be used to infer the mass and radius accurately, and at the same time allow the radius discrepancy to be estimated. Similar systems should be found during the upcoming Kepler mission, and could provide in this way valuable constraints to stellar evolution models in the lower main sequence. The stellar mass and radius of GJ 436 are M*=0.452+0.014-0.012 Msolar and R*=0.464+0.009-0.011 Rsolar, and the radius is 10% larger than predicted by the standard models, in agreement with previous results from well-studied double-lined eclipsing binaries. We obtain an improved planet mass and radius of Mp=23.17+/-0.79 M? and Rp=4.22+0.09-0.10 R?, a density of ?p=1.69+0.14-0.12 g cm-3, and an orbital semimajor axis of a=0.02872+/-0.00027 AU.

Torres, Guillermo

2007-12-01

230

The transiting exoplanet host star GJ 436: a test of stellar evolution models in the lower main sequence, and revised planetary parameters  

CERN Document Server

Knowledge of the stellar parameters for the parent stars of transiting exoplanets is pre-requisite for establishing the planet properties themselves, and often relies on stellar evolution models. GJ 436, which is orbited by a transiting Neptune-mass object, presents a difficult case because it is an M dwarf. Stellar models in this mass regime are not as reliable as for higher mass stars, and tend to underestimate the radius. Here we use constraints from published transit light curve solutions for GJ 436 along with other spectroscopic quantities to show how the models can still be used to infer the mass and radius accurately, and at the same time allow the radius discrepancy to be estimated. Similar systems should be found during the upcoming Kepler mission, and could provide in this way valuable constraints to stellar evolution models in the lower main sequence. The stellar mass and radius of GJ 436 are M = 0.452 [-0.012,+0.014] M(Sun) and R = 0.464 [-0.011,+0.009] R(Sun), and the radius is 10% larger than pr...

Torres, Guillermo

2007-01-01

231

What asteroseismology can do for exoplanets  

CERN Document Server

We describe three useful applications of asteroseismology in the context of exoplanet science: (1) the detailed characterisation of exoplanet host stars; (2) the measurement of stellar inclinations; and (3) the determination of orbital eccentricity from transit duration making use of asteroseismic stellar densities. We do so using the example system Kepler-410 (Van Eylen et al. 2014). This is one of the brightest (V = 9.4) Kepler exoplanet host stars, containing a small (2.8 Rearth) transiting planet in a long orbit (17.8 days), and one or more additional non-transiting planets as indicated by transit timing variations. The validation of Kepler-410 (KOI-42) was complicated due to the presence of a companion star, and the planetary nature of the system was confirmed after analyzing a Spitzer transit observation as well as ground-based follow-up observations.

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

2014-01-01

232

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

233

PULSATION FREQUENCIES AND MODES OF GIANT EXOPLANETS  

International Nuclear Information System (INIS)

We calculate the eigenfrequencies and eigenfunctions of the acoustic oscillations of giant exoplanets and explore the dependence of the characteristic frequency ?0 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 ?0 which gives us an estimate of the scale of the eigenvalue spectrum at high frequency. For the mass range 0.5 MJ ? MP ? 15 MJ , and fixing the planet radius to the Jovian value, we find that ?0 ? 164.0 × (MP /MJ )0.48?Hz, where MP is the planet mass and MJ is Jupiter's mass. For the radius range from 0.9 to 2.0 RJ , and fixing the planet's mass to the Jovian value, we find that ?0 ? 164.0 × (RP /RJ )–2.09?Hz, where RP is the planet radius and RJ is Jupiter's radius. We explore the influence of the presence of a dense core on the pulsation frequencies and on the characteristic frequency of giant exoplanets. We find that the presence find that the presence of heavy elements in the envelope affects the eigenvalue distribution in ways similar to the presence of a dense core. Additionally, we apply our formalism to Jupiter and Saturn and find results consistent with both the observational data of Gaulme et al. and previous theoretical work.

234

Exoplanet Surveys at Universidad de Chile  

Science.gov (United States)

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

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

2014-04-01

235

The GTC exoplanet transit spectroscopy survey I: OSIRIS transmission spectroscopy of the short period planet WASP-43b  

OpenAIRE

We used GTC instrument OSIRIS to obtain long-slit spectra in the optical range (520-1040 nm) of the planetary host star WASP-43 (and a reference star) during a full primary transit event and four partial transit observations. We integrated the stellar flux of both stars in different wavelength regions producing several light curves. We fitted transit models to these curves to measure the star-to-planet radius ratio, Rp/Rs, across wavelength among other physical parameters. W...

Murgas, F.; Palle, E.; Osorio, M. R. Zapatero; Nortmann, L.; Hoyer, S.; Cabrera-lavers, A.

2014-01-01

236

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

CERN Document Server

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 follow-up ground-based observations. The planet has a mass M_p = 3.47 +/- 0.38 M_Jup, a radius R_p = 1.31 +/- 0.18 R_Jup, and a density rho_p = 2.2 +/- 0.8 g/cm3. It orbits a G9V star with a mass M_* = 0.95 +/- 0.15 M_Sun, a radius R_* = 1.00 +/- 0.13 R_Sun, and a rotation period P_rot = 5.4 +/- 0.4 days. The age of the system remains uncertain, stellar evolution models pointing either to a few tens Ma or several Ga, while gyrochronology and lithium abundance point towards ages of a few hundred Ma. This mismatch potentially points to a problem in our understanding of the evolution of young stars, with possible significant implications for stellar physics and the interpretation of inferred sizes of exoplanets around young stars. We detected...

Hebrard, G; Alonso, R; Fridlund, M; Ofir, A; Aigrain, S; Guillot, T; Almenara, J M; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Borde, P; Bouchy, F; Cabrera, J; Carone, L; Carpano, S; Cavarroc, C; Csizmadia, Sz; Deeg, H J; Deleuil, M; Diaz, R F; Dvorak, R; Erikson, A; Ferraz-Mello, S; Gandolfi, D; Gibson, N; Gillon, M; Guenther, E; Hatzes, A; Havel, M; Jorda, L; Lammer, H; Leger, A; Llebaria, A; Mazeh, T; Moutou, C; Ollivier, M; Parviainen, H; Patzold, M; Queloz, D; Rauer, H; Rouan, D; Santerne, A; Schneider, J; Tingley, B; Wuchterl, G

2011-01-01

237

Evolution of Exoplanets and their Parent Stars  

CERN Document Server

Studying exoplanets with their parent stars is crucial to understand their population, formation and history. We review some of the key questions regarding their evolution with particular emphasis on giant gaseous exoplanets orbiting close to solar-type stars. For masses above that of Saturn, transiting exoplanets have large radii indicative of the presence of a massive hydrogen-helium envelope. Theoretical models show that this envelope progressively cools and contracts with a rate of energy loss inversely proportional to the planetary age. The combined measurement of planetary mass, radius and a constraint on the (stellar) age enables a global determination of the amount of heavy elements present in the planet interior. The comparison with stellar metallicity shows a correlation between the two, indicating that accretion played a crucial role in the formation of planets. The dynamical evolution of exoplanets also depends on the properties of the central star. We show that the lack of massive giant planets a...

Guillot, Tristan; Morel, Pierre; Havel, Mathieu; Parmentier, Vivien

2014-01-01

238

Spectra as windows into exoplanet atmospheres.  

Science.gov (United States)

Understanding a planet's atmosphere is a necessary condition for understanding not only the planet itself, but also its formation, structure, evolution, and habitability. This requirement puts a premium on obtaining spectra and developing credible interpretative tools with which to retrieve vital planetary information. However, for exoplanets, these twin goals are far from being realized. In this paper, I provide a personal perspective on exoplanet theory and remote sensing via photometry and low-resolution spectroscopy. Although not a review in any sense, this paper highlights the limitations in our knowledge of compositions, thermal profiles, and the effects of stellar irradiation, focusing on, but not restricted to, transiting giant planets. I suggest that the true function of the recent past of exoplanet atmospheric research has been not to constrain planet properties for all time, but to train a new generation of scientists who, by rapid trial and error, are fast establishing a solid future foundation for a robust science of exoplanets. PMID:24613929

Burrows, Adam S

2014-09-01

239

A Transit Timing Analysis of Nine Rise Light Curves of the Exoplanet System TrES-3  

Science.gov (United States)

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 sstarf = 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.

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

2009-08-01

240

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 dl 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.

241

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

OpenAIRE

The Exoplanet Characterisation Observatory EChO is a space mission concept studied by the European Space Agency in the context of the M3 selection process. Through direct measurement of the atmospheric chemical composition of hundreds of exoplanets, EChO would address fundamental questions such as: What are exoplanets made of? How do planets form and evolve? What is the origin of exoplanet diversity? More specifically, EChO is a dedicated survey mission for transit and eclip...

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

2014-01-01

242

Project PANOPTES: Crowdsourcing the Search for Exoplanets  

Science.gov (United States)

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

Stump, Chad

2014-01-01

243

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

CERN Document Server

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

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

2009-01-01

244

Exoplanet Detection Methods  

CERN Document Server

This chapter reviews various methods of detecting planetary companions to stars from an observational perspective, focusing on radial velocities, astrometry, direct imaging, transits, and gravitational microlensing. For each method, this chapter first derives or summarizes the basic observable phenomena that are used to infer the ex- istence of planetary companions, as well as the physical properties of the planets and host stars that can be derived from the measurement of these signals. This chapter then outlines the general experimental requirements to robustly detect the signals us- ing each method, by comparing their magnitude to the typical sources of measurement uncertainty. This chapter goes on to compare the various methods to each other by outlining the regions of planet and host star parameter space where each method is most sensitive, stressing the complementarity of the ensemble of the methods at our disposal. Finally, there is a brief review of the history of the young exoplanet field, from the f...

Wright, Jason T

2012-01-01

245

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  

CERN Document Server

The CoRoT exoplanet science team announces the discovery of CoRoT-11b, a fairly massive hot-Jupiter transiting a V=12.9 mag F6 dwarf star (M*=1.27 +/- 0.05 Msun, R*=1.37 +/- 0.03 Rsun, Teff=6440 +/- 120 K), with an orbital period of P=2.994329 +/- 0.000011 days and semi-major axis a=0.0436 +/- 0.005 AU. The detection of part of the radial velocity anomaly caused by the Rossiter-McLaughlin effect shows that the transit-like events detected by CoRoT are caused by a planet-sized transiting object in a prograde orbit. The relatively high projected rotational velocity of the star (vsini=40+/-5 km/s) places CoRoT-11 among the most rapidly rotating planet host stars discovered so far. With a planetary mass of mp=2.33+/-0.34 Mjup and radius rp=1.43+/-0.03 Rjup, the resulting mean density of CoRoT-11b (rho=0.99+/-0.15 g/cm^3) can be explained with a model for an inflated hydrogen-planet with a solar composition and a high level of energy dissipation in its interior.

Gandolfi, D; Alonso, R; Deleuil, M; Guenther, E W; Fridlund, M; Endl, M; Eigmüller, P; Csizmadia, Sz; Havel, M; Aigrain, S; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Bordé, P; Bouchy, F; Bruntt, H; Cabrera, J; Carpano, S; Carone, L; Cochran, W D; Deeg, H J; Dvorak, R; Eislöffel, J; Erikson, A; Ferraz-Mello, S; Gazzano, J -C; Gibson, N P; Gillon, M; Gondoin, P; Guillot, T; Hartmann, M; Hatzes, A; Jorda, L; Kabath, P; Léger, A; Llebaria, A; Lammer, H; MacQueen, P J; Mayor, M; Mazeh, T; Moutou, C; Ollivier, M; Pätzold, M; Pepe, F; Queloz, D; Rauer, H; Rouan, D; Samuel, B; Schneider, J; Stecklum, B; Tingley, B; Udry, S; Wuchterl, G; 10.1051/0004-6361/201015132

2010-01-01

246

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

CERN Document Server

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

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

2010-01-01

247

Kepler-447b: a hot-Jupiter with an extremely grazing transit  

CERN Document Server

We present the radial velocity confirmation of the extrasolar planet Kepler-447b, initially detected as a candidate by the Kepler mission. In this work, we analyze its transit signal and the radial velocity data obtained with the Calar Alto Fiber-fed Echelle spectrograph (CAFE). By simultaneously modeling both datasets, we obtain the orbital and physical properties of the system. According to our results, Kepler-447b is a Jupiter-mass planet ($M_p=1.37^{+0.48}_{-0.46} M_{\\rm Jup}$), with an estimated radius of $R_p=1.65^{+0.59}_{-0.56} R_{\\rm Jup}$ (uncertainties provided in this work are $3\\sigma$ unless specified). This translates into a sub-Jupiter density. The planet revolves every $\\sim7.8$ days around a G8V star with detected activity in the Kepler light curve. Kepler-447b transits its host with a large impact parameter ($b=1.076^{+0.112}_{-0.086}$), being one of the few planetary grazing transits confirmed so far and the first in the Kepler large crop of exoplanets. We estimate that only around 20% of ...

Lillo-Box, J; Santos, N C; Mancini, L; Figueira, P; Ciceri, S; Henning, Th

2015-01-01

248

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

Directory of Open Access Journals (Sweden)

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

Lattanzi M.G.

2013-04-01

249

Precise Estimates of the Physical Parameters for the Exoplanet System HD-17156 Enabled by HST FGS Transit and Asteroseismic Observations  

OpenAIRE

We present observations of three distinct transits of HD 17156b obtained with the Fine Guidance Sensors (FGS) on board the Hubble Space Telescope} (HST). We analyzed both the transit photometry and previously published radial velocities to find the planet-star radius ratio R_p/R_s = 0.07454 +/- 0.00035, inclination i=86.49 +0.24/-0.20 deg, and scaled semi-major axis a/R = 23.19 +0.32/-0.27. This last value translates directly to a mean stellar density determination of 0.522 ...

Nutzman, Philip; Gilliland, Ronald L.; Mccullough, Peter R.; Charbonneau, David; Christensen-dalsgaard, Jørgen; Kjeldsen, Hans; Nelan, Edmund P.; Brown, Timothy M.; Holman, Matthew J.

2010-01-01

250

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

CERN Document Server

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

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

2010-01-01

251

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

International Nuclear Information System (INIS)

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 providis, it has the potential of providing novel insights into the origins of giant planets as well as their atmospheric properties

252

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

International Nuclear Information System (INIS)

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

253

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

254

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 dyxoplanets with similar radii and dynamically measured masses

255

The GTC exoplanet transit spectroscopy survey I: OSIRIS transmission spectroscopy of the short period planet WASP-43b  

CERN Document Server

We used GTC instrument OSIRIS to obtain long-slit spectra in the optical range (520-1040 nm) of the planetary host star WASP-43 (and a reference star) during a full primary transit event and four partial transit observations. We integrated the stellar flux of both stars in different wavelength regions producing several light curves. We fitted transit models to these curves to measure the star-to-planet radius ratio, Rp/Rs, across wavelength among other physical parameters. We measure a Rp/Rs in the white light curve of 0.15988^{+0.00133}_{-0.00145}. We present a tentative detection of an excess in the planet-to-star radius ratio around the Na I doublet (588.9 nm, 589.5 nm) when compared to the nearby continuum at the 2.9-sigma level. We find no significant excess of the measured planet-to-star radius ratio around the K I doublet (766.5 nm, 769.9 nm) when compared to the nearby continuum. Combining our observations with previous published epochs, we refine the estimation of the orbital period. Using a linear e...

Murgas, F; Osorio, M R Zapatero; Nortmann, L; Hoyer, S; Cabrera-Lavers, A

2014-01-01

256

Atmospheric Circulation of Exoplanets  

OpenAIRE

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, primi...

Showman, Adam P.; Cho, James Y-k; Menou, Kristen

2009-01-01

257

Exoplanets: A New Era of Comparative Planetology  

Science.gov (United States)

We now know of over 1700 planets orbiting other stars, and several thousand additional planetary candidates. These discoveries have the potential to revolutionize our understanding of planet formation and evolution, while providing targets for the search for life beyond the Solar System. Exoplanets display a larger diversity of planetary types than those seen in our Solar System - including low-density, low-mass objects. They are also found in planetary system architectures very different from our own, even for stars similar to our Sun. Over 20 potentially habitable planets are now known, and half of the M dwarfs stars in our Galaxy may harbor a habitable planet. M dwarfs are plentiful, and they are therefore the most likely habitable planet hosts, but their planets will have radiative and gravitational interactions with their star and sibling planets that are unlike those in our Solar System. Observations to characterize the atmospheres and surfaces of exoplanets are extremely challenging, and transit transmission spectroscopy has been used to measure atmospheric composition for a handful of candidates. Frustratingly, many of the smaller exoplanets have flat, featureless spectra indicative of planet-wide haze or clouds. The James Webb Space Telescope and future ground-based telescopes will improve transit transmission characterization, and enable the first search for signs of life in terrestrial exoplanet atmospheres. Beyond JWST, planned next-generation space telescopes will directly image terrestrial exoplanets, allowing surface and atmospheric characterization that is more robust to haze. Until these observations become available, there is a lot that we can do as planetary scientists to inform required measurements and future data interpretation. Solar System planets can be used as validation targets for extrasolar planet observations and models. The rich heritage of planetary science models can also be used to explore the potential diversity of exoplanet environments and star-planet interactions. And planetary remote-sensing can inform new techniques to identify environmental characteristics and biosignatures in exoplanet spectra.

Meadows, Victoria

2014-11-01

258

Direct Measurement of the Radius and Density of the Transiting Exoplanet HD 189733B with the CHARA Array  

CERN Document Server

We have measured the angular diameter of the transiting extrasolar planet host star HD 189733 using the CHARA O/IR interferometric array. Combining our new angular diameter of 0.377+/-0.024 mas with the Hipparcos parallax leads to a linear radius for the host star of 0.779+/-0.052 Rsol and a radius for the planet of 1.19+/-0.08 RJup. Adopting the mass of the planet as derived by its discoverers, we derive a mean density of the planet of 0.91+/-0.18 g cm-3. This is the first determination of the diameter of an extrasolar planet through purely direct means.

Baines, E K; Brummelaar, T A ten; McAlister, H A; Swain, M; Turner, N H; Sturmann, L; Sturmann, J

2007-01-01

259

Transit spectrophotometry of the exoplanet HD 189733b. II. New Spitzer observations at 3.6 ?m  

Science.gov (United States)

Context. We present a new primary transit observation of the hot-jupiter HD 189733b, obtained at 3.6 ?m 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. Aims: We aim at constraining the atmospheric structure and composition of the planet and improving previously derived parameters. Methods: 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 ?m. 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. Results: We obtained the following system parameters of Rp/R_star = 0.15566+0.00011-0.00024, b = 0.661+0.0053-0.0050, and a/R_star = 8.925+0.0490-0.0523 at 3.6 ?m. These measurements are three times more accurate than previous studies at this wavelength because they benefit from greater observational efficiency and less statistic and systematic errors. Nonetheless, we find that the radius ratio has to be corrected for stellar activity and present a method to do so using ground-based long-duration photometric follow-up in the V-band. The resulting planet-to-star radius ratio corrected for the stellar variability agrees with our previous measurement obtained in the same bandpass. We also discuss that water vapour could not be detected by a comparison of the planetary radius measured at 3.6 and 5.8 ?m, because the radius measured at 3.6 ?m is affected by absorption by other species, possibly Rayleigh scattering by haze.

Désert, J.-M.; Sing, D.; Vidal-Madjar, A.; Hébrard, G.; Ehrenreich, D.; Lecavelier Des Etangs, A.; Parmentier, V.; Ferlet, R.; Henry, G. W.

2011-02-01

260

GTC OSIRIS transiting exoplanet atmospheric survey: detection of potassium in HAT-P-1b from narrowband spectrophotometry  

CERN Document Server

We present the detection of potassium in the atmosphere of HAT-P-1b using optical transit narrowband photometry. The results are obtained using the 10.4 m Gran Telescopio Canarias (GTC) together with the OSIRIS instrument in tunable filter imaging mode. We observed four transits, two at continuum wavelengths outside the potassium feature, at 6792 {\\AA} and 8844 {\\AA}, and two probing the potassium feature in the line wing at 7582.0 {\\AA} and the line core at 7664.9 {\\AA} using a 12 {\\AA} filter width (R~650). The planet-to-star radius ratios in the continuum are found to be $R_{\\rm{pl}}/R_{\\star}$ = 0.1176 $\\pm$ 0.0013 at 6792 {\\AA} and $R_{\\rm{pl}}/R_{\\star}$ = 0.1168 $\\pm$ 0.0022 at 8844 {\\AA}, significantly lower than the two observations in the potassium line: $R_{\\rm{pl}}/R_{\\star}$ = 0.1248 $\\pm$ 0.0014 in the line wing at 7582.0 {\\AA} and $R_{\\rm{pl}}/R_{\\star}$ = 0.1268 $\\pm$ 0.0012 in the line core at 7664.9 {\\AA}. With a weighted mean of the observations outside the potassium feature $R_{\\rm{pl}}/R_...

Wilson, P A; Nikolov, N; Etangs, A Lecavelier des; Pont, F; Fortney, J J; Ballester, G E; López-Morales, M; Désert, J -M; Vidal-Madjar, A

2015-01-01

261

Precise Estimates of the Physical Parameters for the Exoplanet System HD-17156 Enabled by HST FGS Transit and Asteroseismic Observations  

CERN Document Server

We present observations of three distinct transits of HD 17156b obtained with the Fine Guidance Sensors (FGS) on board the Hubble Space Telescope} (HST). We analyzed both the transit photometry and previously published radial velocities to find the planet-star radius ratio R_p/R_s = 0.07454 +/- 0.00035, inclination i=86.49 +0.24/-0.20 deg, and scaled semi-major axis a/R = 23.19 +0.32/-0.27. This last value translates directly to a mean stellar density determination of 0.522 +0.021/-0.018 g cm^-3. Analysis of asteroseismology observations by the companion paper of Gilliland et al. (2009) provides a consistent but significantly refined measurement of the stellar mean density. We compare stellar isochrones to this density estimate and find M_s = 1.275 +/- 0.018 M_sun and a stellar age of $3.37 +0.20/-0.47 Gyr. Using this estimate of M_s and incorporating the density constraint from asteroseismology, we model both the photometry and published radial velocities to estimate the planet radius R_p= 1.0870 +/- 0.0066 ...

Nutzman, Philip; McCullough, Peter R; Charbonneau, David; Christensen-Dalsgaard, Jørgen; Kjeldsen, Hans; Nelan, Edmund P; Brown, Timothy M; Holman, Matthew J

2010-01-01

262

Exoplanet Science with TMT  

Science.gov (United States)

TMT will have unparalleled capabilities for characterizing the composition of extrasolar planets and their atmospheres, and for probing the complex interplay between planet formation, evolution, and migration. In this plenary talk I will summarize these science cases and discuss their synergy with other observing facilities. High-resolution imaging with IRIS and PFI/SEIT will study young, hot planets in nearby star-forming regions, complementing JWST and WFIRST/AFTA coronagraphic efforts at larger semimajor axes. The same instruments will flesh out planets detected by radial velocity (RV) by measuring the albedos and bolometric radii of old, cold Jovian planets and a few ~300 K super-Earths. Complementing JWST and HST studies of short-period transiting planets, NIRES and IRMS spectroscopy will reveal atmospheric composition, dynamics, and thermal structure for dozens of hot Jupiters and Neptunes; NIRES will also produce 2D global maps and movies of a few exoplanets and dozens of brown dwarfs. HROS high-dispersion spectroscopy will precisely measure the composition of extrasolar planetesimals in polluted white dwarfs, and RV followup will continue to exploit the legacies of Kepler, K2, TESS, and PLATO to measure the masses, orbits, and bulk compositions of Earth analogues. Most exciting of all, TMT may facilitate the next major step in the study of exobiology by allowing the detection of biosignature gases around the closest habitable transiting planets.

Crossfield, Ian

2014-07-01

263

Study of TrES-3 Exoplanet  

Science.gov (United States)

The first amateur observation of an exoplanet was made from the Nyrola Observatory in September 16, 2000. (Marko Moilanen, Jalo Ojanperä, Jouni Sorvari, Aki Id and Arto Oksanen). The jovian-type planet orbits a star that is 153 light years far away, and was called HD209458b in Pegasus [1]. The equipment used by this Observatory was a 16 inches MEADE LX200, a ST7E CCD SBIG camera with a V photometric filter and an f/6.3 focal distance reducer. At the University of Nariño Observatory we have a similar equipment. The equipment we employed is: 14"LX200 GPS MEADE telescope and STL-1001 SBIG. The camera we used in our search is much more sensible than the one used by the Nyrola Observatory [2]. From the Astronomical Observatory at the University of Nariño-COLOMBIA, we begun a systematic search for exoplanets. We have already confirmed the transit of the exoplanet TrES-3. This exoplanet was discovered by O'Donovan and other investigators, and turns around the GSC 03089- 00929, with an orbital period of 1.30619 days (31.34856 hours) and inclination of 82.15 deg [3]. The TrES-3 is quite interesting because it has one of the smallest periods found on exoplanets. Jessie L. Christiansen, et.al. observed seven transits and they found that the duration of transit is 81.9+/-1.1 minutes and inclination of 81.99+/-0.30 deg [4], [5]. We have captured a lot of data to elaborate the lightcurves so we can estimate the physical parameters of the exoplanet.

Vodniza, A. Q.; Rojas, M.; Reyes, K.

2011-10-01

264

The spin-orbit alignment of the transiting exoplanet WASP-3b from Rossiter-McLaughlin observations  

CERN Document Server

We present an observation of the Rossiter-McLaughlin effect for the planetary system WASP-3. Radial velocity measurements were made during transit using the SOPHIE spectrograph at the 1.93m telescope at Haute-Provence Observatory. The shape of the effect shows that the sky-projected angle between the stellar rotation axis and planetary orbital axis (lambda) is small and consistent with zero within 2 sigma; lambda = 15 +10/-9 deg. WASP-3b joins the ~two-thirds of planets with measured spin-orbit angles that are well aligned and are thought to have undergone a dynamically-gentle migration process such as planet-disc interactions. We find a systematic effect which leads to an anomalously high determination of the projected stellar rotational velocity (vsini = 19.6 +2.2/-2.1 km/s) compared to the value found from spectroscopic line broadening (vsini = 13.4 +/- 1.5 km/s). This is thought to be caused by a discrepancy in the assumptions made in the extraction and modelling of the data. Using a model developed by Hi...

Simpson, E K; Hebrard, G; Gibson, N P; Barros, S C C; Bouchy, F; Cameron, A Collier; Boisse, I; Watson, C A; Keenan, F P

2009-01-01

265

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

266

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.

267

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

CERN Document Server

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

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

2014-01-01

268

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

CERN Document Server

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

Clanton, Christian

2014-01-01

269

Infrared spectroscopy of exoplanets: observational constraints.  

Science.gov (United States)

The exploration of transiting extrasolar planets is an exploding research area in astronomy. With more than 400 transiting exoplanets identified so far, these discoveries have made possible the development of a new research field, the spectroscopic characterization of exoplanets' atmospheres, using both primary and secondary transits. However, these observations have been so far limited to a small number of targets. In this paper, we first review the advantages and limitations of both primary and secondary transit methods. Then, we analyse what kind of infrared spectra can be expected for different types of planets and discuss how to optimize the spectral range and the resolving power of the observations. Finally, we propose a list of favourable targets for present and future ground-based observations. PMID:24664918

Encrenaz, Thérèse

2014-04-28

270

"Some Like it Hot” - Evidence for the Shrinking Orbit of the 2.2-day Transiting Hot Jupiter Exoplanet HD 189733b - Evidence of Transfer of Planet Orbital Momentum to its Host Star  

Science.gov (United States)

HD189733A is a K2V star that has attracted much attention because it hosts a transiting, hot Jupiter-exoplanet. HD189733b has one of the shortest known orbital-periods (P = 2.22-days) and is only 0.031AU from its host star (Buchy et al. 2005). Based on measurements of the K2V star's P(rot) from starspot-modulations of 12-d, coronal Lx 1028 ergs/s, and chromospheric Ca II-HK emission, indicate an age 0.6 -1.0 Gyr - inferred from our rotation-age-activity relations. However, this age is discrepant with an older-age inferred from the star's low Lithium-abundance ( 1/10 Solar.). However, the age-rotation-activity determination assumes no tidal-effects from close companions- such as close planet. Recently Gaspar et al. (2006) discovered a dM4 companion star (HD 189733 B: 12'' distance to the K-dwarf). X MM-Newton observations of the HD 189733 A&B carried out recently by Pilliteri et al. (2010), surprisingly revealed that HD 189733B shows no X-ray emission, with an upper limit of 9*1026 ergs/s. Using activity-age relationships for dM-stars, we expected a Lx of an order of magnitude higher for age exoplanet candidate systems discovered thus far (Borucki et al. 2010). The analysis these data have reveal that tidal locking between the planet and host star has occurred for a significant number of exoplanet with short orbital periods. We explain the fast rotation of the K2 star via the transfer of the planet's orbital angular momentum to the star via tidal interactions. The significance of these finding with respect to the evolution of planetary systems is discussed. This work is partially supported by NSF/RUI grant AST-1009903.

Santapaga, Thomas; Guinan, E. F.; Ballouz, R.; Engle, S. G.; Dewarf, L.

2011-01-01

271

Direct Imaging of a Cold Jovian Exoplanet in Orbit around the Sun-like Star GJ 504  

CERN Document Server

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 504 b 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 ...

Kuzuhara, M; Kudo, T; Janson, M; Kandori, R; Brandt, T D; Thalmann, C; Spiegel, D; Biller, B; Carson, J; Hori, Y; Suzuki, R; Burrows, A; Henning, T; Turner, E L; McElwain, M W; Moro-Martin, A; Suenaga, T; Takahashi, Y H; Kwon, J; Lucas, P; Abe, L; Brandner, W; Egner, S; Feldt, M; Fujiwara, H; Goto, M; Grady, C A; Guyon, O; Hashimoto, J; Hayano, Y; Hayashi, M; Hayashi, S S; Hodapp, K W; Ishii, M; Iye, M; Knapp, G R; Matsuo, T; Mayama, S; Miyama, S; Morino, J -I; Nishikawa, J; Nishimura, T; Kotani, T; Kusakabe, N; Pyo, T -S; Serabyn, E; Suto, H; Takami, M; Takato, N; Terada, H; Tomono, D; Watanabe, M; Wisniewski, J P; Yamada, T; Takami, H; Usuda, T

2013-01-01

272

Fundamental Parameters of Exoplanets and Their Host Stars  

CERN Document Server

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

Coughlin, Jeffrey L

2013-01-01

273

Observability of the General Relativistic Precession of Periastra in Exoplanets  

OpenAIRE

The general relativistic precession rate of periastra in close-in exoplanets can be orders of magnitude larger than the magnitude of the same effect for Mercury. The realization that some of the close-in exoplanets have significant eccentricities raises the possibility that this precession might be detectable. We explore in this work the observability of the periastra precession using radial velocity and transit light curve observations. Our analysis is independent of the so...

Jordan, Andres; Bakos, Gaspar A.

2008-01-01

274

Exoplanet: Trans-dimentional MCMC method for exoplanet discovery  

Science.gov (United States)

Exoplanet determines the posterior distribution of exoplanets by use of a trans-dimensional Markov Chain Monte Carlo method within Nested Sampling. This method finds the posterior distribution in a single run rather than requiring multiple runs with trial values.

Brewer, Brendon J.

2015-01-01

275

Exoplanets Detection, Formation, Properties, Habitability  

CERN Document Server

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

Mason, John W

2008-01-01

276

The history of exoplanet detection.  

Science.gov (United States)

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. PMID:23013272

Perryman, Michael

2012-10-01

277

Evolution of exoplanets and their parent stars  

Science.gov (United States)

Studying exoplanets with their parent stars is crucial to understand their population, formation and history. We review some of the key questions regarding their evolution with particular emphasis on giant gaseous exoplanets orbiting close to solar-type stars. For masses above that of Saturn, transiting exoplanets have large radii indicative of the presence of a massive hydrogen-helium envelope. Theoretical models show that this envelope progressively cools and contracts with a rate of energy loss inversely proportional to the planetary age. The combined measurement of planetary mass, radius and a constraint on the (stellar) age enables a global determination of the amount of heavy elements present in the planet interior. The comparison with stellar metallicity shows a correlation between the two, indicating that accretion played a crucial role in the formation of planets. The dynamical evolution of exoplanets also depends on the properties of the central star. We show that the lack of massive giant planets and brown dwarfs in close orbit around G-dwarfs and their presence around F-dwarfs are probably tied to the different properties of dissipation in the stellar interiors. Both the evolution and the composition of stars and planets are intimately linked.

Guillot, T.; Lin, D. N. C.; Morel, P.; Havel, M.; Parmentier, V.

2014-11-01

278

Spectroscopy of Exoplanet Atmospheres with the FINESSE Explorer  

Science.gov (United States)

FINESSE (Fast INfrared Exoplanet Spectroscopic Survey Explorer) will provide uniquely detailed information on the growing number of newly discovered planets by characterizing their atmospheric composition and temperature structure. This NASA Explorer mission, selected for a competitive Phase A study, is unique in its breath and scope thanks to broad instantaneous spectroscopy from the optical to the mid-IR (0.7 - 5 micron), with a survey of exoplanets measured in a consistent, uniform way. For 200 transiting exoplanets ranging from Terrestrial to Jovians, FINESSE will measure the chemical composition and temperature structure of their atmospheres and trace changes over time with exoplanet longitude. The mission will do so by measuring the spectroscopic time series for a primary and secondary eclipse over the exoplanet orbital phase curve. With spectrophotometric precision being a key enabling aspect for combined light exoplanet characterization, FINESSE is designed to produce spectrophotometric precision of better than 100 parts-per-million per spectral channel without the need for decorrelation. The exceptional stability of FINESSE will even allow the mission to characterize non-transiting planets, potentially as part of FINESSE's Participating Scientist Program. In this paper, we discuss the flow down from the target availability to observations and scheduling to the analysis and calibration of the data and how it enables FINESSE to be the mission that will truly expand the new field of comparative exoplanetology.

Deroo, Pieter; Swain, Mark R.; Green, Robert O.

2012-01-01

279

Atmospheric Circulation of Exoplanets  

CERN Document Server

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

Showman, Adam P; Menou, Kristen

2009-01-01

280

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

281

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

CERN Document Server

We report on the discovery of a hot Jupiter-type exoplanet, CoRoT-17b, detected by the CoRoT satellite. It has a mass of $2.43\\pm0.30$\\Mjup and a radius of $1.02\\pm0.07$\\Rjup, while its mean density is $2.82\\pm0.38$ g/cm$^3$. CoRoT-17b is in a circular orbit with a period of $3.7681\\pm0.0003$ days. The host star is an old ($10.7\\pm1.0$ Gyr) main-sequence star, which makes it an intriguing object for planetary evolution studies. The planet's internal composition is not well constrained and can range from pure H/He to one that can contain $\\sim$380 earth masses of heavier elements.

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

2011-01-01

282

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

283

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

Science.gov (United States)

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 138×138 spatial elements over a 2.07 arcsec × 2.07 arcsec field of view (FOV). CHARIS will operate in the near infrared (lambda = 1.15 - 2.5 micrometers) and will feature two spectral resolution modes of R is approximately 18 (low-res mode) and R is approximately 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; Groff, Tyler; Kasdin, N. Jeremy; Driscoll, Dave; Galvin, Michael; Foster, Allen; Carr, Michael; LeClerc, Dave; Fagan, Rad; McElwain, Michael; Knapp, Gillian; Brandt, Timothy; Janson, Markus; Guyone, Olivier; Jovanovic, Nemanja; Martinache, Frantz; Hayashi, Masahiko; Takato, Naruhisa

2013-01-01

284

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

285

Light from Exoplanets: Present and Future  

Science.gov (United States)

Measurements using the Spitzer Space Telescope have revealed thermal emission from planets orbiting very close to solar-type stars, primarily transiting "hot Jupiter" exoplanets. The thermal emission spectrum of these worlds has been measured by exploiting their secondary eclipse. Also, during transit of the planet, absorption signatures from atoms and molecules in the planet's atmosphere are imprinted onto the spectrum of the star. Results to date from transit and eclipse studies show that the hot Jupiters often have significant haze and cloud components in their atmospheres, and the temperature structure can often be inverted, i.e. temperature is rising with height. New and very strongly irradiated examples of hot Jupiters have been found that are being stripped of their atmospheres by tidal forces from the star. In parallel, transiting superEarth exoplanets are being discovered, and their atmospheres should also be amenable to study using transit techniques. The 2014 launch of the James Webb Space Telescope will clarify the physical nature of hot Jupiters, and will extend transit and eclipse studies to superEarths orbiting in the habitable zones of lower main sequence stars.

Deming, Leo

2010-01-01

286

Using SPICA Space Telescope to characterize Exoplanets  

CERN Document Server

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

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

2008-01-01

287

Exoplanet Observation from the Vattican Observatory  

Science.gov (United States)

We report our spectroscopic investigation of the transiting hot Jupiter HD 189733b's atmospheric transmission and the first exoplanet transit taken with the Vattican Observatory 1.8m telescope on Mt.Graham using the medium resolution spectrograph VATTSpec. We reconfirm existing planet/star radius ratio measurements with 2675 individual channel measurements spanning ~400-900nm. We provide the first in depth look at the steps necessary for well-calibrated VATTspec observations and provide advice for future observations with this instrument.

Pearson, Kyle; Zellem, Rob; Griffith, Caitlin

2014-11-01

288

Chemical modeling of exoplanet atmospheres  

CERN Document Server

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

Venot, Olivia

2014-01-01

289

32 New Exoplanets Found  

Science.gov (United States)

oday, at an international ESO/CAUP exoplanet conference in Porto, the team who built the High Accuracy Radial Velocity Planet Searcher, better known as HARPS, the spectrograph for ESO's 3.6-metre telescope, reports on the incredible discovery of some 32 new exoplanets, cementing HARPS's position as the world's foremost exoplanet hunter. This result also increases the number of known low-mass planets by an impressive 30%. Over the past five years HARPS has spotted more than 75 of the roughly 400 or so exoplanets now known. "HARPS is a unique, extremely high precision instrument that is ideal for discovering alien worlds," says Stéphane Udry, who made the announcement. "We have now completed our initial five-year programme, which has succeeded well beyond our expectations." The latest batch of exoplanets announced today comprises no less than 32 new discoveries. Including these new results, data from HARPS have led to the discovery of more than 75 exoplanets in 30 different planetary systems. In particular, thanks to its amazing precision, the search for small planets, those with a mass of a few times that of the Earth - known as super-Earths and Neptune-like planets - has been given a dramatic boost. HARPS has facilitated the discovery of 24 of the 28 planets known with masses below 20 Earth masses. As with the previously detected super-Earths, most of the new low-mass candidates reside in multi-planet systems, with up to five planets per system. In 1999, ESO launched a call for opportunities to build a high resolution, extremely precise spectrograph for the ESO 3.6-metre telescope at La Silla, Chile. Michel Mayor, from the Geneva Observatory, led a consortium to build HARPS, which was installed in 2003 and was soon able to measure the back-and-forward motions of stars by detecting small changes in a star's radial velocity - as small as 3.5 km/hour, a steady walking pace. Such a precision is crucial for the discovery of exoplanets and the radial velocity method, which detects small changes in the radial velocity of a star as it wobbles slightly under the gentle gravitational pull from an (unseen) exoplanet, has been most prolific method in the search for exoplanets. In return for building the instrument, the HARPS consortium was granted 100 observing nights per year during a five-year period to carry out one of the most ambitious systematic searches for exoplanets so far implemented worldwide by repeatedly measuring the radial velocities of hundreds of stars that may harbour planetary systems. The programme soon proved very successful. Using HARPS, Mayor's team discovered - among others - in 2004, the first super-Earth (around µ Ara; in 2006, the trio of Neptunes around HD 69830; in 2007, Gliese 581d, the first super Earth in the habitable zone of a small star (eso0722); and in 2009, the lightest exoplanet so far detected around a normal star, Gliese 581e (eso0915). More recently, they found a potentially lava-covered world, with density similar to that of the Earth's (eso0933). "These observations have given astronomers a great insight into the diversity of planetary systems and help us understand how they can form," says team member Nuno Santos. The HARPS consortium was very careful in their selection of targets, with several sub-programmes aimed at looking for planets around solar-like stars, low-mass dwarf stars, or stars with a lower metal content than the Sun. The number of exoplanets known around low-mass stars - so-called M dwarfs - has also dramatically increased, including a handful of super Earths and a few giant planets challenging planetary formation theory. "By targeting M dwarfs and harnessing the precision of HARPS we have been able to search for exoplanets in the mass and temperature regime of super-Earths, some even close to or inside the habitable zone around the star," says co-author Xavier Bonfils. The team found three candidate exoplanets around stars that are metal-deficient. Such stars are thought to be less favourable for the formation of planets, which fo

2009-10-01

290

Signals of exomoons in averaged light curves of exoplanets  

OpenAIRE

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 s...

Simon, A. E.; Szabo?, Gy M.; Kiss, L. L.; Szatma?ry, K.

2011-01-01

291

Synthesizing Exoplanet Demographics from Radial Velocity and Microlensing Surveys. I. Methodology  

Science.gov (United States)

Motivated by the order of magnitude difference in the frequency of giant planets orbiting M dwarfs inferred by microlensing and radial velocity (RV) surveys, we present a method for comparing the statistical constraints on exoplanet demographics inferred from these methods. We first derive the mapping from the observable parameters of a microlensing-detected planet to those of an analogous planet orbiting an RV-monitored star. Using this mapping, we predict the distribution of RV observables for the planet population inferred from microlensing surveys, taking care to adopt reasonable priors for, and properly marginalize over, the unknown physical parameters of microlensing-detected systems. Finally, we use simple estimates of the detection limits for a fiducial RV survey to predict the number and properties of analogs of the microlensing planet population such an RV survey should detect. We find that RV and microlensing surveys have some overlap, specifically for super-Jupiter mass planets (mp >~ 1 M Jup) with periods between ~3-10 yr. However, the steeply falling planetary mass function inferred from microlensing implies that, in this region of overlap, RV surveys should infer a much smaller frequency than the overall giant planet frequency (mp >~ 0.1 M Jup) inferred by microlensing. Our analysis demonstrates that it is possible to statistically compare and synthesize data sets from multiple exoplanet detection techniques in order to infer exoplanet demographics over wider regions of parameter space than are accessible to individual methods. In a companion paper, we apply our methodology to several representative microlensing and RV surveys to derive the frequency of planets around M dwarfs with orbits of <~ 30 yr.

Clanton, Christian; Gaudi, B. Scott

2014-08-01

292

Exoplanets, extremophiles and habitability  

Science.gov (United States)

Estimates of the average surface temperature and CO2 partial atmospheric pressure of already discovered exoplanets supposed to be in their Habitable Zone of their stars were surveyed from the Exoplanet Encyclopedia database. Moreover, since planetary surface temperature strongly depends on its albedo and geodynamic conditions, we have been feeding exoplanetary data into a comprehensive model of Earth's atmosphere to get better estimations. We also investigated the possible presence of "exomoons" belonging to giant planets capable of harbour dynamic stability and to retain atmospheric layers and keep geodynamic activity for long time spans. Collected information on biological data of micro-organisms classified as "extremophiles" indicate that such kind of microbial species could dwell in many of them. We thus propose an extension of the more astronomically defined "Habitable Zone" concept into the more astrobiologically "Extremophile Zone", taking into account other refined parameters allowing survival of more robust life forms.

Janot Pacheco, E.; Bernardes, L.

2012-09-01

293

Atmospheric Dynamics of Exoplanets  

CERN Document Server

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

Heng, Kevin

2014-01-01

294

Tidal Evolution of Exoplanets  

Science.gov (United States)

Tidal effects arise from differential and inelastic deformation of a planet by a perturbing body. The continuous action of tides modify the rotation of the planet together with its orbit until an equilibrium situation is reached. It is often believed that synchronous motion is the most probable outcome of the tidal evolution process, since synchronous rotation is observed for the majority of the satellites in the solar system. However, in the nineteenth century, Schiaparelli also assumed synchronous motion for the rotations of Mercury and Venus, and was later proven wrong. Rather, for planets in eccentric orbits, synchronous rotation is very unlikely. The rotation period and axial tilt of exoplanets is still unknown, but a large number of planets have been detected close to the parent star and should have evolved to a final equilibrium situation. Therefore, based on the well-studied cases in the solar system, we can make some predictions for exoplanets. Here we describe in detail the main tidal effects that modify the secular evolution of the spin and the orbit of a planet. We then apply our knowledge acquired from solar system situations to exoplanet cases. In particular, we will focus on two classes of planets, hot Jupiters (fluid) and super-Earths (rocky with atmosphere).

Correia, A. C. M.; Laskar, J.

2010-12-01

295

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

CERN Document Server

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

296

Transiting exoplanets from the CoRoT space mission. XI. CoRoT-8b: a hot and dense sub-Saturn around a K1 dwarf  

CERN Document Server

We report the discovery of CoRoT-8b, a dense small Saturn-class exoplanet that orbits a K1 dwarf in 6.2 days, and we derive its orbital parameters, mass, and radius. We analyzed two complementary data sets: the photometric transit curve of CoRoT-8b as measured by CoRoT and the radial velocity curve of CoRoT-8 as measured by the HARPS spectrometer. We find that CoRoT-8b is on a circular orbit with a semi-major axis of 0.063 +/- 0.001 AU. It has a radius of 0.57 +/- 0.02 RJ, a mass of 0.22 +/- 0.03 MJ, and therefore a mean density 1.6 +/- 0.1 g/cm^3. With 67 % of the size of Saturn and 72 % of its mass, CoRoT-8b has a density comparable to that of Neptune (1.76 g/cm^3). We estimate its content in heavy elements to be 47-63 Earth masses, and the mass of its hydrogen-helium envelope to be 7-23 Earth masses. At 0.063 AU, the thermal loss of hydrogen of CoRoT-8b should be no more than about 0.1 % over an assumed integrated lifetime of 3~Ga.

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

2010-01-01

297

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.

Keenan F.

2011-02-01

298

The CoRoT mission's exoplanet program  

Directory of Open Access Journals (Sweden)

Full Text Available The CoRoT space observatory was launched at the end of 2006 and has been delivering scientific data from early 2007 until its recent interruption, on 2 Nov. 2012, leading to the discovery of over 30 transiting planets. Here we give an overview over the most relevant results from CoRoT's exoplanet detection program.

Deeg H.J.

2013-04-01

299

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

300

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.

2011-02-01

301

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

OpenAIRE

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

Zeng, Li; Seager, Sara

2008-01-01

302

The search for exomoons and the characterization of exoplanet atmospheres  

CERN Document Server

Since planets were first discovered outside our own Solar System in 1992 (around a pulsar) and in 1995 (around a main sequence star), extrasolar planet studies have become one of the most dynamic research fields in astronomy. Now that more than 370 exoplanets have been discovered, focus has moved from finding planets to characterise these alien worlds. As well as detecting the atmospheres of these exoplanets, part of the characterisation process undoubtedly involves the search for extrasolar moons. A review on the current situation of exoplanet characterization is presented in Chapter 3. We focus on the characterization of transiting planets orbiting very close to their parent star since for them we can already probe their atmospheric constituents. By contrast, the second part of the Chapter is dedicated to the search for extraterrestrial life, both within and beyond the Solar System. The characteristics of the Habitable Zone and the markers for the presence of life (biosignatures) are detailed. In Chapter 4 ...

Campanella, Giammarco

2009-01-01

303

Spitzer Secondary Eclipse Timing Observations of Exoplanets in Eccentric Orbits  

Science.gov (United States)

The Spitzer Exoplanet Target-of-Opportunity program has observed the secondary eclipses of several planets in suspected eccentric orbits around their host stars. The midpoint time determined from each observation can be combined with radial velocity (RV) and transit data to provide improved sets of orbital parameters for a given exoplanet. The orbital phase of the midpoint can be used to establish lower limits on the eccentricity (particularly on ecos?, where e is eccentricity and ? is the argument of periastron) that are independent of RV data. Multiple midpoints can be used to detect parameter variation. We present results for WASP-12b (e systems; and the role of amateur observers as sources of exoplanet data. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA, which provided support for this work.

Ariston Hardy, Ryan; Harrington, J.; Campo, C. J.; Stevenson, K. B.; Nymeyer, S. B.; Blecic, J.; WASP Consortium; Ragozzine, D.; Bakos, G. Á.; Bowman, W. C.; Anzellini, A.

2010-10-01

304

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.

305

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 determinFor 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.

306

Scheduling the EChO survey with known exoplanets  

Science.gov (United States)

The Exoplanet Characterization Observatory (EChO) is a concept of a dedicated space telescope optimized for low-resolution transit and occultation spectroscopy to study the exoplanet diversity through the composition of their atmospheres. The scope of this paper is to answer the following question: Can we schedule a nominal EChO mission, with targets known today (in mid 2013), given the science requirements, realistic performances and operational constraints? We examine this issue from the point of view of duration of the mission and the scheduling restrictions with a sample of exoplanet systems known nowadays. We choose different scheduling algorithms taking into account the science and operational constraints and we verified that it is fairly straightforward to schedule a mission scenario over the lifetime of EChO compliant with the science requirements. We identified agility as a critical constraint that reduces significantly the efficiency of the survey. We conclude that even with known targets today the EChO science objectives can be reached in the 4.5 years duration of the mission. We also show that it is possible to use gaps between exoplanet observations, to fit the required calibration observations, data downlinks and station keeping operations or even to observe more exoplanet targets to be discovered in the coming years.

Morales, J. C.; Beaulieu, J.-P.; Coudé du Foresto, V.; Ollivier, M.; Castello, I. Ortega; Clédassou, R.; Jaubert, J.; Van-Troostenberghe, P.; Varley, R.; Waldmann, I. P.; Pascale, E.; Tessenyi, M.

2014-07-01

307

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

308

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

309

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

OpenAIRE

Aims. We report the discovery of very shallow (?F/F ? 3.4 × 10-4), periodic dips in the light curve of an active V = 11.7 G9V star observed by the CoRoT satellite, which we interpret as caused by a transiting companion. We describe the 3-colour CoRoT data and complementary ground-based observations that support the planetary nature of the companion. Methods. We used CoRoT colours information, good angular resolution ground-based photometric observations in- and out- of transit, adaptive o...

Leger, A.; Rouan, D.; Schneider, J.; Barge, P.; Fridlund, M.; Samuel, B.; Ollivier, M.; Guenther, E.; Deleuil, M.; Deeg, Hj; Auvergne, M.; Alonso, R.; Aigrain, S.; Alapini, A.; Almenara, Jm

2009-01-01

310

KEPLER OBSERVATIONS OF THREE PRE-LAUNCH EXOPLANET CANDIDATES: DISCOVERY OF TWO ECLIPSING BINARIES AND A NEW EXOPLANET  

International Nuclear Information System (INIS)

Three transiting exoplanet candidate stars were discovered in a ground-based photometric survey prior to the launch of NASA's Kepler mission. Kepler observations of them were obtained during Quarter 1 of the Kepler mission. All three stars are faint by radial velocity follow-up standards, so we have examined these candidates with regard to eliminating false positives and providing high confidence exoplanet selection. We present a first attempt to exclude false positives for this set of faint stars without high-resolution radial velocity analysis. This method of exoplanet confirmation will form a large part of the Kepler mission follow-up for Jupiter-sized exoplanet candidates orbiting faint stars. Using the Kepler light curves and pixel data, as well as medium-resolution reconnaissance spectroscopy and speckle imaging, we find that two of our candidates are binary stars. One consists of a late-F star with an early M companion, while the other is a K0 star plus a late M-dwarf/brown dwarf in a 19 day elliptical orbit. The third candidate (BOKS-1) is an r = 15 G8V star hosting a newly discovered exoplanet with a radius of 1.12 RJupiter in a 3.9 day orbit.

311

Tidal Evolution of Exoplanets  

CERN Document Server

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

Correia, Alexandre C M

2010-01-01

312

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

CERN Document Server

We report the detection of CoRoT-23b, a hot Jupiter transiting in front of its host star with a period of 3.6314 \\pm 0.0001 days. This planet was discovered thanks to photometric data secured with the CoRoT satellite, combined with spectroscopic radial velocity (RV) measurements. A photometric search for possible background eclipsing binaries conducted at CFHT and OGS concluded with a very low risk of false positives. The usual techniques of combining RV and transit data simultaneously were used to derive stellar and planetary parameters. The planet has a mass of Mp = 2.8 \\pm 0.3 MJup, a radius of Rpl = 1.05 \\pm 0.13 RJup, a density of \\approx 3 g cm-3. RV data also clearly reveal a non zero eccentricity of e = 0.16 \\pm 0.02. The planet orbits a mature G0 main sequence star of V =15.5 mag, with a mass M\\star = 1.14 \\pm 0.08 M\\odot, a radius R\\star = 1. 61 \\pm 0.18 R\\odot and quasi-solar abundances. The age of the system is evaluated to be 7 Gyr, not far from the transition to subgiant, in agreement with the r...

Rouan, D; Moutou, C; Deleuil, M; Fridlund, M; Ofir, A; Havel, M; Aigrain, S; Alonso, R; Auvergne, M; Baglin, A; Barge, P; Bonomo, A; Bordé, P; Bouchy, F; Cabrera, J; Cavarroc, C; Csizmadia, Sz; Deeg, H; Diaz, R F; Dvorak, R; Erikson, A; Ferraz-Mello, S; Gandolfi, D; Gillon, M; Guillot, T; Hatzes, A; Hébrard, G; Jorda, L; Léger, A; Llebaria, A; Lammer, H; Lovis, C; Mazeh, T; Ollivier, M; Pätzold, M; Queloz, D; Rauer, H; Samuel, B; Santerne, A; Schneider, J; Tingley, B; Wuchterl, G

2011-01-01

313

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

CERN Document Server

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

314

Exploring exoplanet populations with NASA's Kepler Mission.  

Science.gov (United States)

The Kepler Mission is exploring the diversity of planets and planetary systems. Its legacy will be a catalog of discoveries sufficient for computing planet occurrence rates as a function of size, orbital period, star type, and insolation flux. The mission has made significant progress toward achieving that goal. Over 3,500 transiting exoplanets have been identified from the analysis of the first 3 y of data, 100 planets of which are in the habitable zone. The catalog has a high reliability rate (85-90% averaged over the period/radius plane), which is improving as follow-up observations continue. Dynamical (e.g., velocimetry and transit timing) and statistical methods have confirmed and characterized hundreds of planets over a large range of sizes and compositions for both single- and multiple-star systems. Population studies suggest that planets abound in our galaxy and that small planets are particularly frequent. Here, I report on the progress Kepler has made measuring the prevalence of exoplanets orbiting within one astronomical unit of their host stars in support of the National Aeronautics and Space Administration's long-term goal of finding habitable environments beyond the solar system. PMID:25049406

Batalha, Natalie M

2014-09-01

315

A Cloudy View of Exoplanets  

Science.gov (United States)

The lack of absorption features in the transmission spectrum of exoplanet GJ1214b rules out a hydrogen-rich atmosphere for the planet. It is consistent with an atmosphere rich in water vapour or abundant in clouds.

Deming, Drake

2010-01-01

316

Discriminating between Cloudy, Hazy, and Clear Sky Exoplanets Using Refraction  

Science.gov (United States)

We propose a method to distinguish between cloudy, hazy, and clear sky (free of clouds and hazes) exoplanet atmospheres that could be applicable to upcoming large aperture space- and ground-based telescopes such as the James Webb Space Telescope (JWST) and the European Extremely Large Telescope (E-ELT). These facilities will be powerful tools for characterizing transiting exoplanets, but only after a considerable amount of telescope time is devoted to a single planet. A technique that could provide a relatively rapid means of identifying haze-free targets (which may be more valuable targets for characterization) could potentially increase the science return for these telescopes. Our proposed method utilizes broadband observations of refracted light in the out-of-transit spectrum. Light refracted through an exoplanet atmosphere can lead to an increase of flux prior to ingress and subsequent to egress. Because this light is transmitted at pressures greater than those for typical cloud and haze layers, the detection of refracted light could indicate a cloud- or haze-free atmosphere. A detection of refracted light could be accomplished in exoplanets with JWST and <5 hr for super-Earths/mini-Neptunes with E-ELT. We find that this technique is most effective for planets with equilibrium temperatures between 200 and 500 K, which may include potentially habitable planets. A detection of refracted light for a potentially habitable planet would strongly suggest the planet was free of a global cloud or haze layer, and therefore a promising candidate for follow-up observations.

Misra, Amit K.; Meadows, Victoria S.

2014-11-01

317

Visualising Astronomy: Visualising Exoplanet Data  

Science.gov (United States)

Without a doubt, exoplanets represent one of the most engaging and compelling astronomical discoveries of the last two decades. How do we help our public visualise these intriguing objects — these intriguing locations? Earlier in this space1, I have ruminated on the changing nature of visual evidence related to exoplanets, but this time around, I would like to consider how visualisation can help fire people's imaginations, from the perspective of both data and data-driven visuals.

Wyatt, R.

2011-07-01

318

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

OpenAIRE

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

Von Braun, Kaspar; Kane, Stephen R.

2009-01-01

319

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

CERN Document Server

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

320

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

321

The Structure of Exoplanets  

CERN Document Server

The hundreds of exoplanets that have been discovered in the past two decades offer a new perspective on planetary structure. Instead of being the archetypal examples of planets, those of our Solar System are merely possible outcomes of planetary system formation and evolution, and conceivably not even terribly common outcomes (although this remains an open question). Here, we review the diverse range of interior structures that are known to, and speculated to, exist in exoplanetary systems -- from mostly degenerate objects that are more than 10 times as massive as Jupiter, to intermediate-mass Neptune-like objects with large cores and moderate hydrogen/helium envelopes, to rocky objects with roughly the mass of the Earth.

Spiegel, David S; Sotin, Christophe

2013-01-01

322

Structure of exoplanets  

Science.gov (United States)

The hundreds of exoplanets that have been discovered in the past two decades offer a new perspective on planetary structure. Instead of being the archetypal examples of planets, those of our solar system are merely possible outcomes of planetary system formation and evolution, and conceivably not even especially common outcomes (although this remains an open question). Here, we review the diverse range of interior structures that are both known and speculated to exist in exoplanetary systems—from mostly degenerate objects that are more than 10× as massive as Jupiter, to intermediate-mass Neptune-like objects with large cores and moderate hydrogen/helium envelopes, to rocky objects with roughly the mass of Earth. PMID:24379369

Spiegel, David S.; Fortney, Jonathan J.; Sotin, Christophe

2014-01-01

323

Minerva: Big Exoplanet Science from Small Telescopes  

Science.gov (United States)

The Kepler mission has identified over 2300 candidate planets in the past two years, adding to the over 500 confirmed exoplanets from radial velocity (RV) surveys. One of the most striking results of these surveys is that the number of planets increases rapidly with decreasing size. There may in fact be more Earth-like planets in the Galaxy than stars. There must be terrestrial planets around nearby stars, though few have yet been discovered. Finding these planets requires high precision RV observations and high cadence transit observing to densely sample the orbital phase. Minerva will surmount these obstacles with a dedicated observatory for detection of super-Earths and close-in Earth-like planets. Our array of four 0.7-m telescopes will operate in two modes: jointly with a high precision fiber-fed spectrometer capable of detecting the RV signal of an Earth orbiting a low mass star, and independently for photometric transit detection surveys.

McCrady, Nate

2012-10-01

324

The MEarth-North and MEarth-South Transit Surveys: Searching for Habitable Super-Earth Exoplanets Around Nearby M-dwarfs  

Science.gov (United States)

Detection and characterization of potentially habitable Earth-size extrasolar planets is one of the major goals of contemporary astronomy. By applying the transit method to very low-mass M-dwarfs , it is possible to find these planets from the ground with present-day instrumentation and observational techniques. The MEarth project is one such survey with stations in both hemispheres: MEarth-North at the Fred Lawrence Whipple Observatory, Mount Hopkins, Arizona, and MEarth-South at Cerro Tololo Inter-American Observatory, Chile. We present an update on recent results of this survey, for planet occurrence rates, and interesting stellar astrophysics, for which our sample of 3000 nearby mid-to-late M-dwarfs has been very fruitful. All light curves gathered during the survey are made publicly available after one year, and we describe how to access and use these data.

Irwin, Jonathan M.; Berta-Thompson, Zachory K.; Charbonneau, David; Dittmann, Jason; Falco, Emilio E.; Newton, Elisabeth R.; Nutzman, Philip

2015-01-01

325

The MEarth-North and MEarth-South transit surveys: searching for habitable super-Earth exoplanets around nearby M-dwarfs  

CERN Document Server

Detection and characterization of potentially habitable Earth-size extrasolar planets is one of the major goals of contemporary astronomy. By applying the transit method to very low-mass M-dwarfs, it is possible to find these planets from the ground with present-day instrumentation and observational techniques. The MEarth project is one such survey with stations in both hemispheres: MEarth-North at the Fred Lawrence Whipple Observatory, Mount Hopkins, Arizona, and MEarth-South at Cerro Tololo Inter-American Observatory, Chile. We present an update on recent results of this survey, for planet occurrence rates, and interesting stellar astrophysics, for which our sample of 3000 nearby mid-to-late M-dwarfs has been very fruitful. All light curves gathered during the survey are made publicly available after one year, and we describe how to access and use these data.

Irwin, Jonathan M; Charbonneau, David; Dittmann, Jason; Falco, Emilio E; Newton, Elisabeth R; Nutzman, Philip

2014-01-01

326

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

Science.gov (United States)

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

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

2014-02-01

327

Ammonia, Water Clouds and Methane Abundances of Giant Exoplanets and Opportunities for Super-Earth Exoplanets  

OpenAIRE

Future direct-imaging exoplanet missions such as WFIRST/AFTA, Exo-C, and Exo-S will measure the reflectivity of exoplanets at visible wavelengths. The exoplanets to be observed will be located further away from their parent stars than is Earth from the Sun. These "cold" exoplanets have atmospheric environments conducive for the formation of water and/or ammonia clouds, like Jupiter in the Solar System. We study the science return from direct-imaging exoplanet missions, focus...

Hu, Renyu

2014-01-01

328

The NASA Exoplanet Exploration Program  

Science.gov (United States)

The NASA Exoplanet Exploration Program (ExEP) is chartered to implement the NASA space science goals of detecting and characterizing exoplanets and to search for signs of life. The ExEP manages space missions, future studies, technology investments, and ground-based science that either enables future missions or completes mission science. The exoplanet science community is engaged by the Program through Science Definition Teams and through the Exoplanet Program Analysis Group. The ExEP includes the space science missions of Kepler, K2, and the proposed WFIRST-AFTA that includes dark energy science, a widefield infrared survey, a microlensing survey for outer-exoplanet demographics, and a coronagraph for direct imaging of cool outer gas- and ice-giants around nearby stars. Studies of probe-scale (medium class) missions for a coronagraph (internal occulter) and starshade (external occulter) explore the trades of cost and science and provide motivation for a technology investment program to enable consideration of missions at the next decadal survey for NASA Astrophysics. Program elements include follow-up observations using the Keck Observatory which contribute to the science yield of Kepler and K2, and include mid-infrared observations of exo-zodiacal dust by the Large Binocular Telescope Interferometer which provide parameters critical to the design and predicted science yield of the next generation of direct imaging missions. ExEP includes the NASA Exoplanet Science Institute which provides archives, tools, and professional education for the exoplanet community. Each of these program elements contribute to the goal of detecting and characterizing earth-like planets orbiting other stars, and seeks to respond to rapid evolution in this discovery-driven field and to ongoing programmatic challenges through engagement of the scientific and technical communities.

Hudgins, Douglas M.; Blackwood, Gary; Gagosian, John

2014-11-01

329

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

CERN Document Server

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

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

2014-01-01

330

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

Science.gov (United States)

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

Correll, Randall; Worden, S.

2014-01-01

331

OBSERVATIONAL EVIDENCE FOR TIDAL DESTRUCTION OF EXOPLANETS  

International Nuclear Information System (INIS)

The distribution of the orbits of close-in exoplanets shows evidence for ongoing 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 shows good qualitative agreement, suggesting tidal destruction of close-in exoplanets is common. The process can explain the observed cutoff in small semimajor axis 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 semimajor axes, possibly already stripped of any gaseous envelope. The recently discovered CoroT-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 planets have already been accreted, a star may exhibit an unusual composition and/or spin rate.

332

The Exoplanet Microlensing Survey by the Proposed WFIRST Observatory  

Science.gov (United States)

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

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

2012-01-01

333

Evidence for a lost population of close-in exoplanets  

OpenAIRE

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 ob...

Davis, Timothy A.; Wheatley, Peter J.

2009-01-01

334

Massive Satellites of Close-In Gas Giant Exoplanets  

OpenAIRE

We study the orbits, tidal heating and mass loss from satellites around close-in gas giant exoplanets. The focus is on large satellites which are potentially observable by their transit signature. We argue that even Earth-size satellites around hot Jupiters may be immune to destruction by orbital decay; detection of such a massive satellite would strongly constrain theories of tidal dissipation in gas giants, in a manner complementary to orbital circularization. The star's g...

Cassidy, Timothy A.; Mendez, Rolando; Arras, Phil; Johnson, Robert E.; Skrutskie, Michael F.

2009-01-01

335

Direct imaging of exoplanets.  

Science.gov (United States)

Most of the exoplanets known today have been discovered by indirect techniques, based on the study of the host star radial velocity or photometric temporal variations. These detections allowed the study of the planet populations in the first 5-8?AU from the central stars and have provided precious information on the way planets form and evolve at such separations. Direct imaging on 8-10?m class telescopes allows the detection of giant planets at larger separations (currently typically more than 5-10?AU) complementing the indirect techniques. So far, only a few planets have been imaged around young stars, but each of them provides an opportunity for unique dedicated studies of their orbital, physical and atmospheric properties and sometimes also on the interaction with the 'second-generation', debris discs. These few detections already challenge formation theories. In this paper, I present the results of direct imaging surveys obtained so far, and what they already tell us about giant planet (GP) formation and evolution. Individual and emblematic cases are detailed; they illustrate what future instruments will routinely deliver for a much larger number of stars. I also point out the limitations of this approach, as well as the needs for further work in terms of planet formation modelling. I finally present the progress expected in direct imaging in the near future, thanks in particular to forthcoming planet imagers on 8-10?m class telescopes. PMID:24664924

Lagrange, Anne-Marie

2014-04-28

336

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

CERN Document Server

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

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

2010-01-01

337

First Solid Evidence for a Rocky Exoplanet - Mass and density of smallest exoplanet finally measured  

Science.gov (United States)

The longest set of HARPS measurements ever made has firmly established the nature of the smallest and fastest-orbiting exoplanet known, CoRoT-7b, revealing its mass as five times that of Earth's. Combined with CoRoT-7b's known radius, which is less than twice that of our terrestrial home, this tells us that the exoplanet's density is quite similar to the Earth's, suggesting a solid, rocky world. The extensive dataset also reveals the presence of another so-called super-Earth in this alien solar system. "This is science at its thrilling and amazing best," says Didier Queloz, leader of the team that made the observations. "We did everything we could to learn what the object discovered by the CoRoT satellite looks like and we found a unique system." In February 2009, the discovery by the CoRoT satellite [1] of a small exoplanet around a rather unremarkable star named TYC 4799-1733-1 was announced one year after its detection and after several months of painstaking measurements with many telescopes on the ground, including several from ESO. The star, now known as CoRoT-7, is located towards the constellation of Monoceros (the Unicorn) at a distance of about 500 light-years. Slightly smaller and cooler than our Sun, CoRoT-7 is also thought to be younger, with an age of about 1.5 billion years. Every 20.4 hours, the planet eclipses a small fraction of the light of the star for a little over one hour by one part in 3000 [2]. This planet, designated CoRoT-7b, is only 2.5 million kilometres away from its host star, or 23 times closer than Mercury is to the Sun. It has a radius that is about 80% greater than the Earth's. The initial set of measurements, however, could not provide the mass of the exoplanet. Such a result requires extremely precise measurements of the velocity of the star, which is pulled a tiny amount by the gravitational tug of the orbiting exoplanet. The problem with CoRoT-7b is that these tiny signals are blurred by stellar activity in the form of "starspots" (just like sunspots on our Sun), which are cooler regions on the surface of the star. Therefore, the main signal is linked to the rotation of the star, with makes one complete revolution in about 23 days. To get an answer, astronomers had to call upon the best exoplanet-hunting device in the world, the High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph attached to the ESO 3.6-metre telescope at the La Silla Observatory in Chile. "Even though HARPS is certainly unbeaten when it comes to detecting small exoplanets, the measurements of CoRoT-7b proved to be so demanding that we had to gather 70 hours of observations on the star," says co-author François Bouchy. HARPS delivered, allowing the astronomers to tease out the 20.4-hour signal in the data. This figure led them to infer that CoRoT-7b has a mass of about five Earth masses, placing it in rare company as one of the lightest exoplanets yet found. "Since the planet's orbit is aligned so that we see it crossing the face of its parent star - it is said to be transiting - we can actually measure, and not simply infer, the mass of the exoplanet, which is the smallest that has been precisely measured for an exoplanet [3]," says team member Claire Moutou. "Moreover, as we have both the radius and the mass, we can determine the density and get a better idea of the internal structure of this planet." With a mass much closer to that of Earth than, for example, ice giant Neptune's 17 Earth masses, CoRoT-7b belongs to the category of "super-Earth" exoplanets. About a dozen of these bodies have been detected, though in the case of CoRoT-7b, this is the first time that the density has been measured for such a small exoplanet. The calculated density is close to Earth's, suggesting that the planet's composition is similarly rocky. "CoRoT-7b resulted in a 'tour de force' of astronomical measurements. The superb light curves of the space telescope CoRoT gave us the best radius measurement, and HARPS the best mass measurement for an e

2009-09-01

338

Subaru SEEDS Survey of Exoplanets and Disks  

Science.gov (United States)

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

McElwain, Michael W.

2012-01-01

339

Test of multi-object exoplanet search spectral interferometer  

Science.gov (United States)

Exoplanet detection, a highlight in the current astronomy, will be part of puzzle in astronomical and astrophysical future, which contains dark energy, dark matter, early universe, black hole, galactic evolution and so on. At present, most of the detected Exoplanets are confirmed through methods of radial velocity and transit. Guo shoujing Telescope well known as LAMOST is an advanced multi-object spectral survey telescope equipped with 4000 fibers and 16 low resolution fiber spectrographs. To explore its potential in different astronomical activities, a new radial velocity method named Externally Dispersed Interferometry (EDI) is applied to serve Exoplanet detection through combining a fixed-delay interferometer with the existing spectrograph in medium spectral resolution mode (R=5,000-10,000). This new technology has an impressive feature to enhance radial velocity measuring accuracy of the existing spectrograph through installing a fixed-delay interferometer in front of spectrograph. This way produces an interference spectrum with higher sensitivity to Doppler Effect by interference phase and fixed delay. This relative system named Multi-object Exoplanet Search Spectral Interferometer (MESSI) is composed of a few parts, including a pair of multi-fiber coupling sockets, a remote control iodine subsystem, a multi-object fixed delay interferometer and the existing spectrograph. It covers from 500 to 550 nm and simultaneously observes up to 21 stars. Even if it's an experimental instrument at present, it's still well demonstrated in paper that how MESSI does explore an effective way to build its own system under the existing condition of LAMOST and get its expected performance for multi-object Exoplanet detection, especially instrument stability and its special data reduction. As a result of test at lab, inside temperature of its instrumental chamber is stable in a range of +/-0.5degree Celsius within 12 hours, and the direct instrumental stability without further observation correction is equivalent to be +/-50m/s every 20mins.

Zhang, Kai; Wang, Liang; Jiang, Haijiao; Zhu, Yongtian; Hou, Yonghui; Dai, Songxin; Tang, Jin; Tang, Zhen; Zeng, Yizhong; Chen, Yi; Wang, Lei; Hu, Zhongwen

2014-07-01

340

Microlensing by Exoplanets  

Science.gov (United States)

Gravitational microlensing occurs when a foreground star happens to pass very close to our line of sight to a more distant background star. The foreground star acts as a lens, splitting the light from the background source star into two images, which are typically unresolved. However, these images of the source are also magnified, by an amount that depends on the angular separation between the lens and source. The relative motion between the lens and source therefore results in a time-variable magnification of the source: a microlensing event. If the foreground star happens to host a planet with projected separation near the paths of these images, the planet will also act as a lens, further perturbing the images and resulting in a characteristic, short-lived signature of the planet. This chapter provides an introduction to the discovery and characterization of exoplanets with gravitational microlensing. The theoretical foundation of the method is reviewed, focusing in particular on the phenomenology of planetary microlensing perturbations. The strengths and weaknesses of the microlensing technique are discussed, highlighting the fact that it is sensitive to low-mass planetary companions to stars throughout the galactic disk and foreground bulge, and that its sensitivity peaks for planet separations just beyond the snow line. An overview of the practice of microlensing planet searches is given, with a discussion of some of the challenges with detecting and analyzing planetary perturbations. The chapter concludes with a review of the results that have been obtained to date, and a discussion of the near- and long-term prospects for microlensing planet surveys. Ultimately, microlensing is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury, as well as to free-floating planets, and will provide a crucial test of planet formation theories by determining the demographics of planets throughout the galaxy.

Gaudi, B. S.

2010-12-01

341

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

342

Three Distinct Exoplanet Regimes Inferred From Host Star Metallicities  

Science.gov (United States)

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

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

2014-06-01

343

EChOSim: The Exoplanet Characterisation Observatory software simulator  

CERN Document Server

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

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

2014-01-01

344

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; 10.1051/0004-6361/201220945

2013-01-01

345

Cloud Base Signature in Transmission Spectra of Exoplanet Atmospheres  

Science.gov (United States)

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

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

2014-07-01

346

Cloud Base Signature in Transmission Spectra of Exoplanet Atmospheres  

CERN Document Server

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

Vahidinia, Sanaz; Marley, Mark; Fortney, Jonathan

2014-01-01

347

The Observational Effects and Signatures of Tidally Distorted Solid Exoplanets  

CERN Document Server

Our work examines the detectability of tidally distorted solid exoplanets in synchronous rotation. Previous work has shown that tidally distorted shapes of close-in gas giants can give rise to radius underestimates and subsequently density overestimates for those planets. We examine the assumption that such an effect is too minimal for rocky exoplanets and find that for smaller M Class stars there may be an observationally significant tidal distortion effect at very close-in orbits. We quantify the effect for different stellar types and planetary properties using some basic assumptions. Finally, we develop a simple analytic expression to test if there are detectable bulge signatures in the photometry of a system. We find that close in for smaller M Class stars there may be an observationally significant signature that may manifest itself in both in-transit bulge signatures and ellipsoidal variations.

Saxena, Prabal; Summers, Michael

2014-01-01

348

The observational effects and signatures of tidally distorted solid exoplanets  

Science.gov (United States)

Our work examines the detectability of tidally distorted solid exoplanets in synchronous rotation. Previous work has shown that tidally distorted shapes of close-in gas giants can give rise to radius underestimates and subsequently density overestimates for those planets. We examine the assumption that such an effect is too minimal for rocky exoplanets and find that for smaller M Class stars there may be an observationally significant tidal distortion effect at very close-in orbits. We quantify the effect for different stellar types and planetary properties using some basic assumptions. Finally, we develop a simple analytic expression to test if there are detectable bulge signatures in the photometry of a system. We find that close in for smaller M Class stars there may be an observationally significant signature that may manifest itself in both in-transit bulge signatures and ellipsoidal variations.

Saxena, Prabal; Panka, Peter; Summers, Michael

2015-02-01

349

Stellar Magnetism and starspots: the implications for exoplanets  

Science.gov (United States)

Stellar variability induced by starspots can hamper the detection of exoplanets and bias planet property estimations. These features can also be used to study star-planet interactions as well as inferring properties from the underlying stellar dynamo. However, typical techniques, such as ZDI, are not possible for most host-stars. We present a robust method based on spot modelling to map the surface of active star allowing us to statistically study the effects and interactions of stellar magnetism with transiting exoplanets. The method is applied to the active Kepler-9 star where we find small evidence for a possible interaction between planet and stellar magnetosphere which leads to a 2:1 resonance between spot rotation and orbital period.

Vilela, Conrad; Southworth, John; del Burgo, Carlos

2014-08-01

350

Transiting exoplanets from the CoRoT space mission XXVIII. CoRoT-28b, a planet orbiting an evolved star, and CoRoT-29b, a planet showing an asymmetric transit  

CERN Document Server

Context. We present the discovery of two transiting extrasolar planets by the satellite CoRoT. Aims. We aim at a characterization of the planetary bulk parameters, which allow us to further investigate the formation and evolution of the planetary systems and the main properties of the host stars. Methods. We used the transit light curve to characterize the planetary parameters relative to the stellar parameters. The analysis of HARPS spectra established the planetary nature of the detections, providing their masses. Further photometric and spectroscopic ground-based observations provided stellar parameters (log g,Teff,v sin i) to characterize the host stars. Our model takes the geometry of the transit to constrain the stellar density into account, which when linked to stellar evolutionary models, determines the bulk parameters of the star. Because of the asymmetric shape of the light curve of one of the planets, we had to include the possibility in our model that the stellar surface was not strictly spherical...

Cabrera, J; Montagnier, G; Fridlund, M; Eiff, M Ammler-von; Chaintreuil, S; Damiani, C; Deleuil, M; Ferraz-Mello, S; Ferrigno, A; Gandolfi, D; Guillot, T; Guenther, E W; Hatzes, A; Hébrard, G; Klagyivik, P; Parviainen, H; Pasternacki, Th; Pätzold, M; Sebastian, D; Santos, M Tadeu dos; Wuchterl, G; Aigrain, S; Alonso, R; Almenara, J -M; Armstrong, J D; Auvergne, M; Baglin, A; Barge, P; Barros, S C C; Bonomo, A S; Bordé, P; Bouchy, F; Carpano, S; Chaffey, C; Deeg, H J; Díaz, R F; Dvorak, R; Erikson, A; Grziwa, S; Korth, J; Lammer, H; Lindsay, C; Mazeh, T; Moutou, C; Ofir, A; Ollivier, M; Pallé, E; Rauer, H; Rouan, D; Samuel, B; Santerne, A; Schneider, J

2015-01-01

351

The Radiation Environment of Exoplanet Atmospheres  

Directory of Open Access Journals (Sweden)

Full Text Available Exoplanets are born and evolve in the radiation and particle environment created by their host star. The host star’s optical and infrared radiation heats the exoplanet’s lower atmosphere and surface, while the ultraviolet, extreme ultraviolet and X-radiation control the photochemistry and mass loss from the exoplanet’s upper atmosphere. Stellar radiation, especially at the shorter wavelengths, changes dramatically as a host star evolves leading to changes in the planet’s atmosphere and habitability. This paper reviews the present state of our knowledge concerning the time-dependent radiation emitted by stars with convective zones, that is stars with spectral types F, G, K, and M, which comprise nearly all of the host stars of detected exoplanets.

Jeffrey L. Linsky

2014-10-01

352

Increasing the sensitivity of Kepler to Earth-like exoplanets  

Science.gov (United States)

Many transiting exoplanets have been discovered using photometry from the Kepler mission but the results are still very incomplete in some of the most interesting parts of parameter space: small planetary radius and long orbital period. We have developed a method for detecting transiting exoplanet signals in stellar light curves that is more sensitive to small planets on long orbits than previously published procedures. It is standard practice to start by "de-trending" the light curves—by filtering—to remove the instrumental systematics and stellar variability from the time series. Instead, we build an flexible model for these effects using a Gaussian Process. We use as inputs to the Gaussian Process not just time but also the light curves of dozens of other stars. This exploits the causal structure of the problem: permitting the noise model to capture spacecraft-induced covariability. Since we know a priori that the other stars are causally unrelated to the star of interest, any information that they share must be due to systematics. A key motivation for our work is that any filtering—no matter how robust—reduces the amplitude of the signals of interest. By marginalizing over the stellar and instrumental variability while simultaneously fitting for the transits, we maintain sensitivity to transit signals and reduce contamination. We apply our method to light curves from the Kepler mission. Using synthetic transits generated by realistic planetary systems injected into raw aperture photometry from the pipeline, we determine the detection efficiency of our method and train a supervised classification algorithm to weed out false signals. Our pipeline returns all of the ingredients needed for studies of exoplanet populations: a catalog of planet candidates, posterior samples for the physical parameters of these planets and their host stars, and an empirical measurement of the detection efficiency as a function of all of these parameters.

Foreman-Mackey, Daniel; Hogg, David W.; Schölkopf, Bernhard; Wang, Dun

2015-01-01

353

The Brown Dwarf-Exoplanet Connection  

OpenAIRE

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

Burgasser, Adam J.

2009-01-01

354

On the Confidence of Molecular Detections in the Atmospheres of Exoplanets from Secondary Eclipse Spectra  

Science.gov (United States)

Armed with a sizable and ever-growing list of confirmed exoplanets we are beginning to face the big question of atmospheric characterization: What are these planets made of? Transit transmission and emission spectroscopy provide a means to probe the composition of exoplanet atmospheres. However, relatively few high-resolution spectra have been obtained for transiting exoplanets leaving attempts at atmospheric characterization to rely heavily on ground and space-based broadband photometric observations. More recently, early claims of molecular detections in exoplanet atmospheres using broadband photometry are called into question as featureless blackbodies can be shown to reproduce the low signal-to-noise observations. In this study, we determine with what confidence we are able to detect spectrally dominant molecules in the atmospheres of nine exoplanets observed in secondary eclipse. Using the Bayesian atmospheric retrieval suite, CHIMERA, we find that the detection of molecules from broadband ground-based and space-based photometry generally fails to breach 3? confidence. However, observations that include spectral data lead to strong molecular detections. Furthermore, we simulate Hubble Space Telescope Wide Field Camera 3 spectral observations from 1.1 to 1.6 microns for a handful of planets to suggest how future observations may lead to molecular detections.

Lustig-Yaeger, Jacob A.; Line, Michael R.; Fortney, Jonathan J.

2015-01-01

355

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 Document Server

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

356

Atmospheric Circulation of Terrestrial Exoplanets  

CERN Document Server

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

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

2013-01-01

357

Mapping Directly Imaged Giant Exoplanets  

OpenAIRE

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 m...

Kostov, Veselin B.; Apai, Da?niel

2012-01-01

358

STELLAR VARIABILITY OF THE EXOPLANET HOSTING STAR HD 63454  

International Nuclear Information System (INIS)

Of the hundreds of exoplanets discovered using the radial velocity (RV) technique, many are orbiting close to their host stars with periods less than 10 days. One of these, HD 63454, is a young active K dwarf which hosts a Jovian planet in a 2.82 day period orbit. The planet has a 14% transit probability and a predicted transit depth of 1.2%. Here we provide a re-analysis of the RV data to produce an accurate transit ephemeris. We further analyze 8 nights of time series data to search for stellar activity both intrinsic to the star and induced by possible interactions of the exoplanet with the stellar magnetospheres. We establish the photometric stability of the star at the 3 mmag level despite strong Ca II emission in the spectrum. Finally, we rule out photometric signatures of both star-planet magnetosphere interactions and planetary transit signatures. From this we are able to place constraints on both the orbital and physical properties of the planet.

359

JWST and Exoplanets  

Science.gov (United States)

The James Webb Space Telescope is on track for a launch in 2013. The author reviews the status and progress on the key hardware. The first primary mirror segments are already at MSFC for cryogenic tests, the mid IR instrument (MIRI) has already had successful tests of the engineering model, and the detectors are showing excellent performance. The author also describes the scientific objectives of the mission, with emphasis on the predicted capabilities for observing planets by the transit technique and through direct imaging. Recent direct observations of planets by HST and by adaptive optics from the ground have shown that, under favorable circumstances, much can be learned.

Mather, John C.

2009-01-01

360

Constraining Exoplanet Mass from Transmission Spectroscopy  

Science.gov (United States)

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

de Wit, Julien; Seager, Sara

2013-12-01

361

Achieving high-precision pointing on ExoplanetSat: Initial feasibility analysis  

OpenAIRE

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

Pong, Christopher Masaru; Lim, Sungyung; Smith, Matthew William; Miller, David W.; Villasenor, Jesus Noel Samonte; Seager, Sara

2010-01-01

362

Exoplanet Community Report on Direct Infrared Imaging of Exoplanets  

Science.gov (United States)

Direct infrared imaging and spectroscopy of exoplanets will allow for detailed characterization of the atmospheric constituents of more than 200 nearby Earth-like planets, more than is possible with any other method under consideration. A flagship mission based on larger passively cooled infrared telescopes and formation flying technologies would have the highest angular resolution of any concept under consideration. The 2008 Exoplanet Forum committee on Direct Infrared Imaging of Exoplanets recommends: (1) a vigorous technology program including component development, integrated testbeds, and end-to-end modeling in the areas of formation flying and mid-infrared nulling; (2) a probe-scale mission based on a passively cooled structurally connected interferometer to be started within the next two to five years, for exoplanetary system characterization that is not accessible from the ground, and which would provide transformative science and lay the engineering groundwork for the flagship mission with formation flying elements. Such a mission would enable a complete exozodiacal dust survey (<1 solar system zodi) in the habitable zone of all nearby stars. This information will allow for a more efficient strategy of spectral characterization of Earth-sized planets for the flagship missions, and also will allow for optimization of the search strategy of an astrometric mission if such a mission were delayed due to cost or technology reasons. (3) Both the flagship and probe missions should be pursued with international partners if possible. Fruitful collaboration with international partners on mission concepts and relevant technology should be continued. (4) Research and Analysis (R&A) should be supported for the development of preliminary science and mission designs. Ongoing efforts to characterize the the typical level of exozodiacal light around Sun-like stars with ground-based nulling technology should be continued.

Danchi, William C.; Lawson, Peter R.

2009-01-01

363

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.

2013-04-01

364

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

365

EMPIRICAL CONSTRAINTS ON THE OBLATENESS OF AN EXOPLANET  

International Nuclear Information System (INIS)

We show that the gas giant exoplanet HD 189733b is less oblate than Saturn, based on Spitzer Space Telescope photometry of seven transits. The observable manifestations of oblateness would have been slight anomalies during the ingress and egress phases, as well as variations in the transit depth due to spin precession. Our nondetection of these effects gives the first empirical constraints on the shape of an exoplanet. The results are consistent with the theoretical expectation that the planetary rotation period and orbital period are synchronized, in which case the oblateness would be an order of magnitude smaller than our upper limits. Conversely, if HD 189733b is assumed to be in a synchronous, zero-obliquity state, then the data give an upper bound on the quadrupole moment of the planet (J2 < 0.068 with 95% confidence) that is too weak to constrain the interior structure of the planet. An Appendix describes a fast algorithm for computing the transit light curve of an oblate planet, which was necessary for our analysis.

366

Empirical Constraints on the Oblateness of an Exoplanet  

CERN Document Server

We show that the gas giant exoplanet HD 189733b is less oblate than Saturn, based on Spitzer Space Telescope photometry of seven transits. The observable manifestations of oblatenesswould have been slight anomalies during the ingress and egress phases, as well as variations in the transit depth due to spin precession. Our nondetection of these effects gives the first empirical constraints on the shape of an exoplanet. The results are consistent with the theoretical expectation that the planetary rotation period and orbital period are synchronized, in which case the oblateness would be an order of magnitude smaller than our upper limits. Conversely, if HD 189733b is assumed to be in a synchronous, zero-obliquity state, then the data give an upper bound on the quadrupole moment of the planet (J2 < 0.068 with 95% confidence) that is too weak to constrain the interior structure of the planet. An Appendix describes a fast algorithm for computing the transit light curve of an oblate planet, which was necessary f...

Carter, Joshua A

2009-01-01

367

Insolation patterns on eccentric exoplanets  

Science.gov (United States)

Several studies have found that synchronously-rotating Earth-like planets in the habitable zones of M-dwarf stars should exhibit an "eyeball" climate pattern, with a pupil of open ocean facing the parent star, and ice everywhere else. Recent work on eccentric exoplanets by Wang et al. (Wang, Y., Tian, F., Hu, Y. [2014b] Astrophys. J. 791, L12) has extended this conclusion to the 2:1 spin-orbit resonance as well, where the planet rotates twice during one orbital period. However, Wang et al. also found that the 3:2 and 5:2 half-odd resonances produce a zonally-striped climate pattern with polar icecaps instead. Unfortunately, they used incorrect insolation functions for the 3:2 and 5:2 resonances whose long-term time averages are essentially independent of longitude. This paper presents the correct insolation patterns for eccentric exoplanets with negligible obliquities in the 0:1, 1:2, 1:1, 3:2, 2:1, 5:2, 3:1, 7:2, and 4:1 spin-orbit resonances. I confirm that the mean insolation is distributed in an eyeball pattern for integer resonances; but for half-odd resonances, the mean insolation takes a "double-eyeball" pattern, identical over the "eastern" and "western" hemispheres. Presuming that liquids, ices, clouds, albedo, and thermal emission are similarly distributed, this has significant implications for the observation and interpretation of potentially habitable exoplanets. Finally, whether a striped ball, eyeball, or double-eyeball pattern emerges, the possibility exists that long-term build-up of ice (or liquid) away from the hot spots may alter the planet's inertia tensor and quadrupole moments enough to re-orient the planet, ultimately changing the distribution of liquid and ice.

Dobrovolskis, Anthony R.

2015-04-01

368

High Contrast Imaging: A New Frontier for Exoplanets Search and Characterization  

Science.gov (United States)

The discovery of 51 Peg in 1995 initiated the search for extrasolar planets with radial velocity. Since then, more than 330 expoplanets have been discovered with this successful technique. After a more timid start, the search for extrasolar planets with the transit method has begun to collect very promising results (55 planets discovered up till now). COROT, Kepler, TESS and ground-based surveys will provide many more candidates in a short term future. Moreover, for a selected sample of transiting exoplanets it is already possible to probe their atmospheres. Although very successful, both these methods are sensitive to planets which orbit quite close to their parent star. High contrast imaging will be the new frontier for exoplanet search and characterization. This technique will provide the opportunity to explore planets with masses down to the earth mass and/or orbiting at larger separation from their parent star, especially in the habitable zone. The possibility to couple an integral field spectrograph to a module for extreme adaptive optics and a 8m class telescope (SPHERE for VLT and GPI for South Gemini) or in the future to ELTs (EPICS), will allow to characterize the atmospheres of the observed exoplanets with low resolution spectroscopy. Here we present the advantages and limits of the high contrast imaging technique to detect and characterize exoplanets in the short and long term future, expecially compared to the RV and Transit methods.

Claudi, R. U.; Bonavita, M.; Desidera, S.; Gratton, R.; Tinetti, G.; Beuzit, J.; Kasper, M.; Mordassini, C.

2011-12-01

369

Prospecting For Habitable SuperEarth Exoplanets With The MEarth Observatory  

Science.gov (United States)

When exoplanets are observed to transit their parent stars, we are granted direct estimates of their masses and radii, and we can undertake studies of their atmospheres. As a result, such systems have profoundly impacted our understanding of the physics of exoplanets, yet to date only large exoplanets (akin to Jupiter or Neptune) are known to transit their parent stars. By targeting nearby M-dwarf stars, a transit search using modest equipment is capable of discovering planets as small as 2 Earth radii in the habitable zones of their host stars. The discovery of such planets is important for two reasons: First, they provide fundamental constraints on the physical structure of planets that are primarily rock and ice in composition. Second, by differencing spectra gathered when the planet is in view from those when it is occulted by the star, we can study the atmospheric chemistry of potentially habitable worlds. The MEarth Project will consist of 8 identical, automated 16-inch telescopes in a single enclosure at Mt Hopkins, AZ. Five of these telescopes are currently in operation. We will describe the target sample, survey design, and the current photometric precision, with the goal of demonstrating the feasibility of the ground-based detection of habitable exoplanets. We acknowledge funding from the National Science Froundation and the David and Lucile Packard Fellowship for Science and Engineering.

Charbonneau, David; Irwin, J.; Nutzman, P.; Falco, E. E.

2008-09-01

370

Exoplanet Forecast: Hot and Wet  

Science.gov (United States)

[figure removed for brevity, see original site] Click on image for larger poster version This plot of data from NASA's Spitzer Space Telescope tells astronomers that a toasty gas exoplanet, or a planet beyond our solar system, contains water vapor. Spitzer observed the planet, called HD 189733b, cross in front of its star at three different infrared wavelengths: 3.6 microns; 4.5 microns and 8 microns (see lime-colored dots). For each wavelength, the planet's atmosphere absorbed different amounts of the starlight that passed through it. The pattern by which this absorption varies with wavelength matches known signatures of water, as shown by the theoretical model in blue.

2007-01-01

371

Resource Letter Exo-1: Exoplanets  

CERN Document Server

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

Perryman, Michael

2013-01-01

372

A Model for Thermal Phase Variations of Circular and Eccentric Exoplanets  

OpenAIRE

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 cur...

Cowan, Nicolas B.; Agol, Eric

2010-01-01

373

Generation of a target list of observable exoplanets for The Exoplanet Characterisation Observatory (EChO)  

Science.gov (United States)

The science of extrasolar planets is one of the most rapidly changing areas of astrophysics and since 1995 the number of planets known has increased by almost two orders of magnitude. A combination of groundbased surveys and dedicated space missions has resulted in 800-plus planets being detected, and over 2000 that await confirmation. NASA's Kepler mission has opened up the possibility of discovering Earthlike planets in the habitable zone around some of the 100,000 stars it is surveying during its 3 to 4-year lifetime. The new ESA's Gaia mission is expected to discover thousands of new planets around stars within 200 parsecs of the Sun. The key challenge now is moving on from discovery, important though that remains, to characterisation: what are these planets actually like, and why are they as they are? The Exoplanet Characterisation Observatory (EChO) is a space mission dedicated to undertaking spectroscopy of transiting exoplanets over the widest range possible. In the frame of ESA's Cosmic Vision programme, EChO has been considered as medium-sized M3 mission candidate for launch in the 2022 - 2024 timeframe [1]. Survey missions like EChO require the generation of a target list of observable objects. The choices made in the selection is important to maximise the mission efficiency and breath of science. By running the current population of targets through the EChO end-toend simulator, EChOSim [2], we can tell if a target can reach the required signal to noise, how many orbits it will take and how much EChO time it will use. In this conference we describe the methods used to choose our target list, the assumptions made and some of the tools we created. We will present our estimates of the observability of the current population of targets with EChO.

Varley, R.; Waldmann, I. P.; Tessenyi, M.; Tinetti, G.; Ollivier, M.; Coudé du Foresto, V.; Pascale, E.; Swinyard, B.; Osborn, H.; Martinod, M.

2013-09-01

374

Astrometric exoplanet detection with Gaia  

CERN Document Server

We provide a revised assessment of the number of exoplanets that should be discovered by Gaia astrometry, extending previous studies to a broader range of spectral types, distances, and magnitudes. Our assessment is based on a large representative sample of host stars from the TRILEGAL Galaxy population synthesis model, recent estimates of the exoplanet frequency distributions as a function of stellar type, and detailed simulation of the Gaia observations using the updated instrument performance and scanning law. We use two approaches to estimate detectable planetary systems: one based on the S/N of the astrometric signature per field crossing, easily reproducible and allowing comparisons with previous estimates, and a new and more robust metric based on orbit fitting to the simulated satellite data. With some plausible assumptions on planet occurrences, we find that some 21,000 (+/-6000) high-mass (1-15M_J) long-period planets should be discovered out to distances of ~500pc for the nominal 5-yr mission (incl...

Perryman, Michael; Bakos, Gáspár; Lindegren, Lennart

2014-01-01

375

Highlights in the study of exoplanet atmospheres.  

Science.gov (United States)

Exoplanets are now being discovered in profusion. To understand their character, however, we require spectral models and data. These elements of remote sensing can yield temperatures, compositions and even weather patterns, but only if significant improvements in both the parameter retrieval process and measurements are made. Despite heroic efforts to garner constraining data on exoplanet atmospheres and dynamics, reliable interpretation has frequently lagged behind ambition. I summarize the most productive, and at times novel, methods used to probe exoplanet atmospheres; highlight some of the most interesting results obtained; and suggest various broad theoretical topics in which further work could pay significant dividends. PMID:25230656

Burrows, Adam S

2014-09-18

376

Highlights in the Study of Exoplanet Atmospheres  

CERN Document Server

Exoplanets are now being discovered in profusion. However, to understand their character requires spectral models and data. These elements of remote sensing can yield temperatures, compositions, and even weather patterns, but only if significant improvements in both the parameter retrieval process and measurements are achieved. Despite heroic efforts to garner constraining data on exoplanet atmospheres and dynamics, reliable interpretation has oftimes lagged ambition. I summarize the most productive, and at times novel, methods employed to probe exoplanet atmospheres, highlight some of the most interesting results obtained, and suggest various broad theoretical topics in which further work could pay significant dividends.

Burrows, Adam

2014-01-01

377

Transits of Earth-Like Planets  

OpenAIRE

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 detec...

Kaltenegger, L.; Traub, W. A.

2009-01-01

378

Characterization of Exoplanet Atmospheres and Kepler Planet Candidates with Multi-Color Photometry from the Gran Telescopio Canarias  

Science.gov (United States)

With over 180 confirmed transiting exoplanets and NASA's Kepler mission's recent discovery of over 1200 transiting exoplanet candidates, we can conduct detailed investigations into the (i) properties of exoplanet atmospheres and (ii) false positive rates for planet search surveys. To aid these investigations, we developed a novel technique of using the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) installed on the 10.4-meter Gran Telescopio Canarias (GTC) to acquire near-simultaneous multi-color photometry of (i) HD 80606b in bandpasses around the potassium (K I) absorption feature, (ii) GJ 1214b in bandpasses around a possible methane absorption feature and (iii) several Kepler planet candidates. For HD 80606b, we measure a significant color change during transit between wavelengths that probe the K I line core and the K I wing, equivalent to a 4.2% change in the apparent planetary radius. We hypothesize that the excess absorption may be due to K I in a high-speed wind being driven from the exoplanet's exosphere. This is one of the first detections of K I in an exoplanet atmosphere. For GJ 1214b, we compare the transit depths measured "on” and "off” a possible methane absorption feature and use our results to help resolve conflicting results from other studies regarding the composition of this super-Earth-size planet's atmosphere. For Kepler candidates, we use the color change during transit to reject candidates that are false positives (e.g., a blend with an eclipsing binary either in the background/foreground or bound to the target star). We target small planets (orbital periods (exoplanet follow-up.

Colon, Knicole; Ford, E. B.

2012-01-01

379

Exploring exoplanet populations with NASA’s Kepler Mission  

Science.gov (United States)

The Kepler Mission is exploring the diversity of planets and planetary systems. Its legacy will be a catalog of discoveries sufficient for computing planet occurrence rates as a function of size, orbital period, star type, and insolation flux. The mission has made significant progress toward achieving that goal. Over 3,500 transiting exoplanets have been identified from the analysis of the first 3 y of data, 100 planets of which are in the habitable zone. The catalog has a high reliability rate (85–90% averaged over the period/radius plane), which is improving as follow-up observations continue. Dynamical (e.g., velocimetry and transit timing) and statistical methods have confirmed and characterized hundreds of planets over a large range of sizes and compositions for both single- and multiple-star systems. Population studies suggest that planets abound in our galaxy and that small planets are particularly frequent. Here, I report on the progress Kepler has made measuring the prevalence of exoplanets orbiting within one astronomical unit of their host stars in support of the National Aeronautics and Space Administration’s long-term goal of finding habitable environments beyond the solar system. PMID:25049406

Batalha, Natalie M.

2014-01-01

380

Transitions.  

Science.gov (United States)

Includes four articles: "Career Aspirations" (Field); "Making the Transition to a New Curriculum" (Baker, Householder); "How about a 'Work to School' Transition?" (Glasberg); and "Technological Improvisation: Bringing CNC to Woodworking" (Charles, McDuffie). (SK)

Field, David; And Others

1992-01-01

381

Atmospheric Chemistry of Venus-like Exoplanets  

OpenAIRE

We use thermodynamic calculations to model atmospheric chemistry on terrestrial exoplanets that are hot enough for chemical equilibira 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 surface. These results will be useful in planning future observations of the atmospheres of terrestrial-sized exoplanets by ...

Schaefer, Laura; Fegley Jr, Bruce

2010-01-01

382

Observational Evidence for Tidal Destruction of Exoplanets  

OpenAIRE

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-va...

Jackson, Brian; Barnes, Rory; Greenberg, Richard

2009-01-01

383

Keplerian Orbits and Dynamics of Exoplanets  

OpenAIRE

Understanding the consequences of the gravitational interaction between a star and a planet is fundamental to the study of exoplanets. The solution of the two-body problem shows that the planet moves in an elliptical path around the star and that each body moves in an ellipse about the common center of mass. The basic properties of such a system are derived from first principles and described in the context of detecting exoplanets.

Murray, Carl D.; Correia, Alexandre C. M.

2010-01-01

384

Light scattering from exoplanet oceans and atmospheres  

OpenAIRE

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 = 180 deg, whereas ocean planets with transparent atmospheres should reach peak brightness in crescent phase near OL = 30 deg. Application of Fresnel theory to a planet with no atmosphere covered by a calm ocean predicts a peak ...

Zugger, Michael E.; Kasting, James F.; Williams, Darren M.; Kane, Timothy J.; Philbrick, C. Russell

2010-01-01

385

Theoretical Spectra of Terrestrial Exoplanet Surfaces  

OpenAIRE

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...

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

2012-01-01

386

Balloon Exoplanet Nulling Interferometer (BENI)  

Science.gov (United States)

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

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

2009-01-01

387

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

CERN Document Server

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

388

Observing Exoplanet Atmospheres: Recent Results from ESO and National Facilities  

International Nuclear Information System (INIS)

Full text: Planetary transits and occultations are currently our best windows toward the study of exoplanet atmospheres. Occultations, i.e. passages of the planet behind the star, yield a measure of the planetary spectral energy distribution and thereby allow to investigate the atmospheric temperature structure, heat redistribution efficiency, albedo, and to place constraints on the atmospheric composition. Transits in turn allow to probe for wavelength dependencies in the effective planetary radius that are sensitive to signatures of chemical elements in the planetary atmosphere. We present results of ongoing observing campaigns studying the atmospheres of the very short-period planet WASP-19b and the low-density hot Saturn WASP-49b. (author)

389

WASP-29b: Another Cool Exoplanet With Abundant CO?  

Science.gov (United States)

Stevenson et al. (2010, Nature 464, 1161-1164) made the surprising discovery of a lack of methane (CH4) and abundant carbon monoxide (CO) on the cool exoplanet GJ 436b. This was based on a nondetection at 4.5 microns (CO band), a strong detection at 3.6 microns (CH4 band), and a weak signal at 8.0 microns (CH4 band). At GJ 436b's equilibrium temperature of 770 K, CH4 is thermochemically favored over CO. We present a second cool exoplanet that also features a detection at 3.6 microns and a nondetection at 4.5 microns, suggesting strong CO absorption. The transiting extrasolar planet WASP-29b was discovered by the Wide Angle Search for Planets by Hellier et al. (2010, ApJL 723, L60-L63). WASP-29b is a hot Saturn with a equilibrium temperature of 980 K. It orbits a K4 dwarf star every 3.922 days at a distance of 0.0457 AU. We analyze lightcurves from two Spitzer 3.6 micron secondary eclipses taken in August 2010 and January 2011, and one Spitzer 4.5 micron secondary eclipse taken in January 2011. We detect no eclipse in the 4.5 micron observation. This mirrors the results of Stevenson et al. for GJ 436b and suggests that WASP-29b may also have abundant CO. We strongly detect eclipses in the 3.6 micron observations, which provide timing constraints for all three observations. The lack of an 8.0 micron observation prevents us from confirming a lack of methane. K-band observations would help to address its abundance. These observations are part of the Spitzer Exoplanet Target of Opportunity program. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA, which provided support for this work.

Hardin, Matthew; Harrington, J.; Stevenson, K.; Blecic, J.; Bowman, O.; Cubillos, P.; Nymeyer, S.; Consortium, WASP

2012-10-01

390

BIOSIGNATURE GASES IN H2-DOMINATED ATMOSPHERES ON ROCKY EXOPLANETS  

International Nuclear Information System (INIS)

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, using a model atmosphere with photochemistry and a biomass estimate framework for evaluating the plausibility 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 accumulate detectable biosignature gases in an H2 atmosphere is closely analogous to the case of oxidized atmospheres, where photochemically produced OH is the major destructive species. Most potential biosignature gases, such as dimethylsulfide and CH3Cl, are therefore more favorable in low-UV, as compared with solar-like UV, environments. A few promising biosignature gas candidates, including NH3 and N2O, are favorable even in solar-like UV environments, as these gases are destroyed directly by photolysis and not by H (or O). A more subtle finding is that most gases produced by life that are fully hydrogenated forms of an element, such as CH4 and H2S, are not effective signs of life in an H2-rich atmosphere because the dominant atmospheric chemistry will generate such gases abiologically, through photochemistry or geochemistry. Suitable biosignature gases in H2-rich atmospheres for super-Earth exoplanets transiting M stars could potentially be detected in transmission spectra with the James Webb Space Telescope

391

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 <1?; a non-precessing solution fits better. We also comment on analysis and reporting for Spitzer exoplanet porting for Spitzer exoplanet data in light of recent re-analyses.

392

Young, Jupiter-Mass Objects in Ophiuchus  

Science.gov (United States)

We have used 3.5 to 8 ?m data from the Cores to Disks (c2d) Legacy survey and our own deep IJHKs images of a 0.5 square degree portion of the c2d fields in Ophiuchus to produce a sample of candidate young objects with probable masses between 1 and 10 MJupiter. The availability of photometry over whole range where these objects emit allows us to discriminate between young, extremely low-mass candidates and more massive foreground and background objects and means our survey will have fewer false positives than existing near-IR surveys. The sensitive inventory of a star forming cloud from the red to the mid-IR will allow us to constrain the IMF for these non-clustered star formation regions to well below the deuterium burning limit. For stars with fluxes in the broad gap between the 2MASS limits and our limits, our data will provide information about the photospheres. We will use the Spitzer results in combination with current disk models to learn about the presence and nature of circumstellar disks around young brown dwarfs.

Allers, K. N.; Jaffe, D. T.; van der Bliek, N. S.; Allard, F.; Baraffe, I.

2006-12-01

393

OPTICAL PHASE CURVES OF KEPLER EXOPLANETS  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-07-20

394

The multiplicity status of three exoplanet host stars  

Science.gov (United States)

Aims: The goal of our ongoing study of exoplanet host stars is to determine the true multiplicity rate of such stars. For this purpose we aim to research a statistically significant and homogeneously analyzed sample of stars around which planets have been found by the radial velocity or the transiting method. Ultimately, we want to determine if there are significant differences between planets in single- and multiple-star systems. This could indicate different formation scenarios. In this research note, we specifically investigate the companionship of three low-mass stellar candidate companions to exoplanet hosts via second epoch imaging and astrometry. Methods: We used various high-resolution imaging instruments in order to search for low-mass stellar companions to exoplanet host stars. Images were taken at a minimum of two observation epochs to check whether detected companion candidates are co-moving with the primary stars. We used the known photometric data of the primary stars together with theoretical evolutionary models in order to calculate detection limits for all targets and to estimate the mass of confirmed companions. Results: With our astrometric data we can confirm for the first time that the exoplanet host star HAT-P-8 has a low-mass stellar companion with an absolute magnitude in the K-band of 7.37 ± 0.15 mag and an estimated mass of 0.25 M?. However, in our high-resolution VLT/NACO observation the source appears elongated and could therefore be a close binary. If both of the binary components are equally massive, this binary could have a higher total mass of ~0.35 M?. In addition, we were able to calculate detection limits for the HAT-P-30 system and the HD 44219 system and showed that companion candidates around these objects are most likely background objects. Based on observations obtained at Paranal Observatory in ESO programs 089.C-0638(A) and 090.C-0125(A), as well as archive data of ESO programs 088.D-0473(A), 088.C-0843(B), and 184.D-1152(C).

Ginski, C.; Mugrauer, M.; Seeliger, M.; Löhne, T.

2013-11-01

395

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

396

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

397

Transient Sulfate Aerosols as a Signature of Exoplanet Volcanism  

CERN Document Server

Geological activity is thought to be important for the origin of life and for maintaining planetary habitability. We show that transient sulfate aerosols could be a signature of exoplanet volcanism, and therefore a geologically active world. A detection of transient aerosols, if linked to volcanism, could thus aid in habitability evaluations of the exoplanet. On Earth, subduction-induced explosive eruptions inject SO2 directly into the stratosphere, leading to the formation of sulfate aerosols with lifetimes of months to years. We demonstrate that the rapid increase and gradual decrease in sulfate aerosol loading associated with these eruptions may be detectable in transit transmission spectra with future large-aperture telescopes, such as the James Webb Space Telescope (JWST) and European Extremely-Large Telescope (E-ELT) for a planetary system at a distance of 10 pc, assuming an Earth-like atmosphere, bulk composition, and size. Specifically, we find that a S/N of 12.1 and 7.1 could be achieved with E-ELT (...

Misra, Amit; Koehler, Matthew C; Sholes, Steven

2015-01-01

398

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

CERN Document Server

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

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

2014-01-01

399

Probe-Scale Mission Concepts for Direct Imaging and Spectroscopy of Nearby Exoplanet Systems  

Science.gov (United States)

Two mission concepts are now under study for detecting visible light from exoplanets orbiting nearby stars through high-contrast imaging and for characterizing them through spectroscopy. Exo-S uses a starshade (external occulter) that flies in front of a telescope to block out the central starlight; Exo-C uses a coronagraph with an internal occulter to accomplish the suppression of starlight. Both concepts have the objective of taking optical spectra of nearby exoplanets in reflected light, searching for previously undetected planets, and imaging structure in circumstellar debris disks.The concepts are being developed by two NASA-selected community-led Science and Technology Definition Teams (STDTs), supported by study design teams from NASA's Exoplanet Exploration Program. In addition to developing concepts with an estimated cost ~1B, the Teams are identifying key enabling technologies needed for their designs. These concepts complement existing NASA missions that do exoplanet science (such as transit spectroscopy and debris disk imaging with HST and Spitzer) or are under development or active study (TESS, JWST, WFIRST-AFTA).Final Reports from the two studies will be published in early 2015. This poster serves as an introduction to a series of posters featuring the two studies. At the conclusion of the studies in early 2015, NASA will evaluate them for further technology development and possible development as flight missions. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Unwin, Stephen C.; Seager, Sara; Stapelfeldt, Karl R.; Warfield, Keith; Dekens, Frank G.; Blackwood, Gary; Exo-S Science; Technology Definition Team, Exo-C Science; Technology Definition Team, JPL Probe Study Design Teams

2015-01-01

400

Detecting industrial pollution in the atmospheres of earth-like exoplanets  

OpenAIRE

Detecting biosignatures, such as molecular oxygen in combination with a reducing gas, in the atmospheres of transiting exoplanets has been a major focus in the search for alien life. We point out that in addition to these generic indicators, anthropogenic pollution could be used as a novel biosignature for intelligent life. To this end, we identify pollutants in the Earth's atmosphere that have significant absorption features in the spectral range covered by the James Webb S...

Lin, Henry W.; Abad, Gonzalo Gonzalez; Loeb, Abraham

2014-01-01

401

Using the Inclinations of Kepler Systems to Prioritize New Titius-Bode-Based Exoplanet Predictions  

OpenAIRE

We analyze a sample of multiple-exoplanet systems which contain at least 3 transiting planets detected by the Kepler mission ("Kepler multiples"). We use a generalized Titius-Bode relation to predict the periods of 228 additional planets in 151 of these Kepler multiples. These Titius-Bode-based predictions suggest that there are, on average, ~2 planets in the habitable zone of each star. We estimate the inclination of the invariable plane for each system and prioritize our p...

Bovaird, Timothy; Lineweaver, Charles H.; Jacobsen, Steffen K.

2014-01-01

402

Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars  

OpenAIRE

We present four new exoplanets: HIP 14810 b & c, HD 154345 b, and HD 187123 c. The two planets orbiting HIP 14810, from the N2K project, have masses of 3.9 and 0.76 M_jup. We have searched the radial velocity time series of 90 known exoplanet systems and found new residual trends due to additional, long period companions. Two stars known to host one exoplanet have sufficient curvature in the residuals to a one planet fit to constrain the minimum mass of the outer companion t...

Wright, J. T.; Marcy, G. W.; Fischer, D. A.; Butler, R. P.; Vogt, S. S.; Tinney, C. G.; Jones, H. R. A.; Carter, B. D.; Johnson, J. A.; Mccarthy, C.; Apps, K.

2006-01-01

403

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

404

TMT and Exoplanet Radial Velocity Surveys  

Science.gov (United States)

With echelle spectrometers on the verge of crossing over the 0.1 m/s radial velocity (RV) measurement precision threshold needed to detect habitable Earth mass planets around Sun-like stars, conducing such surveys on state-of-the-art telescopes is an imperative. RV exoplanets surveys conducted with the optical and infrared echelle spectrometers being built for the TMT have the potential to complete a census of the population of Earth-mass planets in our local stellar neighborhood. The detection of such systems will provide a valuable stellar sample for follow-up exoplanet studies which would characterize the atmospheres of these or additional planets found in these nearby solar systems. Here, we will further discuss the impact of the TMT on radial velocity exoplanet surveys.

Tanner, Angelle; Crossfield, Ian

2014-07-01

405

Constraining exoplanet mass from transmission spectroscopy.  

Science.gov (United States)

Determination of an exoplanet's mass is a key to understanding its basic properties, including its potential for supporting life. To date, mass constraints for exoplanets are predominantly based on radial velocity (RV) measurements, which are not suited for planets with low masses, large semimajor axes, or those orbiting faint or active stars. Here, we present a method to extract an exoplanet's mass solely from its transmission spectrum. We find good agreement between the mass retrieved for the hot Jupiter HD 189733b from transmission spectroscopy with that from RV measurements. Our method will be able to retrieve the masses of Earth-sized and super-Earth planets using data from future space telescopes that were initially designed for atmospheric characterization. PMID:24357312

de Wit, Julien; Seager, Sara

2013-12-20

406

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  

CERN Document Server

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 ten transits of HAT-P-4, estimating the planet radius Rp = 1.332 \\pm 0.052 RJup, the stellar radius R \\star = 1.602 \\pm 0.061 R \\odot, the inclination i = 89.67 \\pm 0.30 degrees and the transit duration from first to fourth contact T = 255.6 \\pm 1.9 minutes. For TrES-3, we observe seven transits, and find Rp = 1.320 \\pm 0.057 RJup, R\\star = 0.817 \\pm 0.022 R\\odot, i = 81.99 \\pm 0.30 degrees and T = 81.9 \\pm 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 \\pm 0.034 RJup, R\\star = 0.940 \\pm 0.026 R\\odot, i = 84.15 \\pm 0.16 degrees and T = 107.3 \\pm 1.1 minutes. Finally...

Christiansen, Jessie L; Charbonneau, David; Deming, Drake; Holman, Matthew J; Madhusudhan, Nikku; Seager, Sara; Wellnitz, Dennis D; Barry, Richard K; Livengood, Timothy A; Hewagama, Tilak; Hampton, Don L; Lisse, Carey M; A'Hearn, Michael F

2010-01-01

407

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

CERN Document Server

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

Guenther, E W; Gazzano, J -C; Mazeh, T; Rouan, D; Gibson, N; Csizmadia, Sz; Aigrain, S; Alonso, R; Almenara, J M; Auvergne, M; Baglin, A; Barge, P; Bonomo, A S; Borde, P; Bouchy, F; Bruntt, H; Cabrera, J; Carone, L; Carpano, S; Cavarroc, C; Deeg, H J; Deleuil, M; Dreizler, S; Dvorak, R; Erikson, A; Ferraz-Mello, S; Fridlund, M; Gandolfi, D; Gillon, M; Guillot, T; Hatzes, A; Havel, M; Hebrard, G; Jehin, E; Jorda, L; Lammer, H; Leger, A; Moutou, C; Nortmann, L; Ollivier, M; Ofir, A; Pasternacki, Th; Paetzold, M; Parviainen, H; Queloz, D; Rauer, H; Samuel, B; Santerne, A; Schneider, J; Tal-Or, L; Tingley, B; Weingrill, J; Wuchterl, G

2011-01-01

408

The discovery of a new ELL variable star in Centaurus and possibility of detecting new exoplanets using the FRAM telescope  

Science.gov (United States)

We report on the discovery of a new variable star during the search for new exoplanets in the Centaurus constellation from the archive of the FRAM telescope, operated by the FRAM team at Los Leones, near Malargüe, Argentina. The star is catalogued as GSC 08630-01117 (11h 36m 10s -53° 12' 15.04"). From the light curve, the star should be an ELL-type variable. We computed the period P = 0.6311+/- 0.0002 days. The maximum is 13.07 +/- 0.02 mag and minimum is 13.22 +/-0.02 mag (in the Johnson V filter) with an amplitude of about 0.15 mag. We registered this star in the CzeV catalogue and in the VSX catalogue as new variable star CzeV603. The FRAM telescope observed several transits of known exoplanets. These observations show the ability to detect new exoplanets using the FRAM telescope.

Pintr, Pavel; Vápenka, David; Mašek, Martin

2015-01-01

409

Characterizing the Parents: Exoplanets Around Cool Stars  

OpenAIRE

The large majority of stars in the Milky Way are late-type dwarfs, and the frequency of low-mass exoplanets in orbits around these late-type dwarfs appears to be high. In order to characterize the radiation environments and habitable zones of the cool exoplanet host stars, stellar radius and effective temperature, and thus luminosity, are required. It is in the stellar low-mass regime, however, where the predictive power of stellar models is often limited by sparse data volu...

Von Braun, Kaspar; Boyajian, Tabetha S.; Belle, Gerard T.; Mann, Andrew; Kane, Stephen R.

2014-01-01

410