WorldWideScience
 
 
1

The sub-Jupiter mass transiting exoplanet WASP-11b  

CERN Document Server

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

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

2008-01-01

2

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

CERN Document Server

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

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

2010-01-01

3

Exoplanet Detection: Transit Method  

Science.gov (United States)

The Exoplanet Detection: Transit Method model simulates the detection of exoplanets by using the transit method of detecting exoplanets. In this method, the light curve from a star, and how it changes over time due to exoplanet transits, is observed and then analyzed. In this simulation the exoplanet orbits the star (sun-sized) in circular motion via Kepler's third law.  When the exoplanet passes in front of the star (transits), it blocks part of the starlight. This decrease in starlight is shown on the graph.  If the exoplanet is close enough to the central star, and has sufficient reflectivity, or albedo, it can reflect enough of the starlight to be seen on the light curve. In the simulation the star-exoplanet system is shown as seen from Earth (edge on view) but magnified greatly, and with the star and planet sizes not shown to the scale of the orbit. The radius of the central star (relative to the radius of Sun),semi-major axis of the exoplanet (in AU), radius of the exoplanet (relative to the radius of Jupiter), the exoplanet's albedo (reflectivity), and the inclination of the system relative to Earth can be changed. The simulation uses Java 3D, if installed, to render the view the star and exoplanet. If Java 3D is not installed, the simulation will default to simple 3D using Java.

Belloni, Mario

2010-06-29

4

Exoplanet Transit Parallax  

CERN Document Server

The timing and duration of exoplanet transits has a dependency on observer position due to parallax. In the case of an Earth-bound observer with a 2 AU baseline the dependency is typically small and slightly beyond the limits of current timing precision capabilities. However, it can become an important systematic effect in high-precision repeated transit measurements for long period systems due to its relationship to secular perspective acceleration phenomena. In this short paper we evaluate the magnitude and characteristics of transit parallax in the case of exoplanets using simplified geometric examples. We also discuss further implications of the effect, including its possible exploitation to provide immediate confirmation of planetary transits and/or unique constraints on orbital parameters and orientations.

Schärf, C A

2007-01-01

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

6

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

7

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

8

HAT-P-28b AND HAT-P-29b: TWO SUB-JUPITER MASS TRANSITING PLANETS  

International Nuclear Information System (INIS)

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 days 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 days 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.

9

Factors Affecting the Radii of Close-in Transiting Exoplanets  

CERN Document Server

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

Enoch, B; Horne, K

2012-01-01

10

Transiting Exoplanet Observations at Grinnell College  

Science.gov (United States)

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

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

2014-01-01

11

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

12

The Transiting Exoplanet Survey Satellite  

CERN Document Server

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

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

2014-01-01

13

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

14

Transit Exoplanet Survey in Antarctic Dome A  

Science.gov (United States)

Antarctic is an ideal and unique site on Earth for astronomical observations. Due to its low water content, low turbulent atmosphere zone and 24 hours uninterrupted observations during its winter time, it is an extremely good place for transit exoplanet survey which requires high photometric precision. 4 small telescopes (CSTAR) with diameter 14.5 centimeters have been put in Antarctic Kunlun station (Dome A), and operated since 2008. Three telescopes (AST3) with diameters around 50 centimeters each will be placed in Dome A within next few years. Here we report our planned transit survey in AST3, aiming at finding exoplanets at middle distance to their host stars. The planet candidates found through AST3 will be followed by a late-coming 2.5-meter telescope called KDUST. Some preliminary exoplanet candidates revealed by the ongoing CSTAR will be presented. The work is supported by Nanjing University’s 985 Funds, and Funds form NSFC.

Zhou, Jilin; Sun, Y.; Zhang, H.; Li, M.; Yang, J.; Chen, Y.

2011-09-01

15

The Transiting Exoplanet Survey Satellite Mission  

Science.gov (United States)

(Abstract only) 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 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. TESS stars will typically be 30 to 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. All of the half-million plus TESS targets will be observed at a rapid cadence (1 minute or less). Hence, the brighter TESS stars will potentially yield valuable asteroseismic information. TESS 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 serve as the "People's Telescope," with 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 been selected by NASA for launch in 2017 as an Astrophysics Explorer mission.

Ricker, G. R.

2014-06-01

16

The Transiting Exoplanet Survey Satellite Mission  

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 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 several 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 1 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 serve as the “People’s Telescope,” with 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 been selected by NASA for launch in 2017 as an Astrophysics Explorer mission.

Ricker, George R.; Vanderspek, Roland Kraft; Latham, David W.; Winn, Joshua N.

2014-06-01

17

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

18

Mass-loss rates for transiting exoplanets  

CERN Document Server

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), heating efficiencies (eta), 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 10^6 to 10^13 g/s for various conservative assumptions. High heating efficiencies would imply that hot exoplan...

Ehrenreich, David

2011-01-01

19

Searching for transit timing variations in transiting exoplanet systems  

CERN Document Server

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

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

2008-01-01

20

Tidal dynamics of transiting exoplanets  

Science.gov (United States)

Transits give us the mass, radius, and orbital properties of the planet, all of which inform dynamical theories. Two properties of the hot Jupiters suggest they had a dramatic origin via tidal damping from high eccentricity. First, the tidally circularized planets (in the 1-4 day pile-up) lie along a relation or boundary in the mass-period plane. This observation may implicate a tidal damping process regulated by planetary radius inflation and Roche lobe overflow, early in the planets' lives. Second, the host stars of many planets have spins misaligned from the planets' orbits. This observation was not expected a priori from the conventional disk migration theory, and it was a boon for the alternative theories of planet-planet scattering and Kozai cycles, accompanied by tidal friction, which predicted it. Now we are faced with a curious observation that the misalignment angle depends on the stellar temperature. It may mean that the tide raised on the stars realigns them, the final result being the tidal consumption of hot Jupiters.

Fabrycky, Daniel C.

2011-11-01

 
 
 
 
21

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

22

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

23

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

24

Colour Magnitude Diagrams of Transiting Exoplanets  

Science.gov (United States)

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

Triaud, Amaury H. M. J.

2014-06-01

25

Target of Opportunity: New Transiting Exoplanets  

Science.gov (United States)

We propose a Target of Opportunity (ToO) program to observe eclipses of new extrasolar planets. The measured band fluxes constrain models of composition, chemistry, and atmospheric dynamics. They also provide the basic information needed for follow-on work. Since the spacecraft is nearing the end of its limited lifetime, rapid characterization is crucial. Well below Spitzer's nominal sensitivity, these measurements are challenging, and optimized observing and analysis techniques that are not obvious are required to bring in the best signal. Many Discretionary Time proposals have been approved on this topic. Our goals, achieved with our Cycle-3 ToO program and continued here, are to ensure that each bandpass is observed for every planet with good predicted S/N, to obtain the best possible observations, to make these high-impact data public for everyone to use in planning followups, and to make the process of observing exoplanets smooth for observers and Spitzer by allocating a predictable number of events for the community through the TAC process. Based on actual discovery statistics and the known quantities of survey data in hand, we confidently predict about 22 new transiting-planet announcements in the coming year. Of these, one may be bright enough to measure in six bandpasses, and several may be marginal for Spitzer. We thus request 120 hours to cover about 18 6:40-hour eclipse events in low-impact ToOs. We provide quantitative criteria for activating ToOs. Our archival product will be calibrated lightcurves, to be submitted as electronic attachments with journal articles. Transiting extrasolar planets are among the least anticipated and most productive targets for Spitzer. They are also among the most publicly stimulating. These direct measurements provide the only emission fluxes possible with current telescopes for extrasolar planets, and stand as a Spitzer legacy for posterity. The next opportunity to observe them is with JWST.

Harrington, Joseph; Bakos, Gaspar; Deming, Drake; Fischer, Debra; Seager, Sara; Wheatley, Peter

2007-05-01

26

Parametrized post-Newtonian secular transit timing variations for exoplanets  

Science.gov (United States)

Ground-based and space-borne observatories used for studying exoplanet transits now and in the future will considerably increase the number of exoplanets known from transit data and the precision of the measured times of transit minima. Variations in the transit times can not only be used to infer the presence of additional planets, but might also provide opportunities to test the general theory of relativity in these systems. To build a framework for these possible tests, we extend previous studies on the observability of the general relativistic precessions of periastron in transiting exoplanets to variations in secular transit timing under parametrized post-Newtonian formalism. We find that if one can measure the difference between observed and predicted variations of general relativistic secular transit timing to 1 s yr-1 in a transiting exoplanet system with a Sun-like mass, a period of ~ 1 day and a relatively small eccentricity of ~ 0.1, general relativity will be tested to the level of ~ 6%.

Zhao, Shan-Shan; Xie, Yi

2013-10-01

27

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

28

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-12-20

29

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

International Nuclear Information System (INIS)

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

30

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

31

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

CERN Document Server

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

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

2012-01-01

32

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

33

Kepler mission exoplanet transit data analysis using fractal imaging  

Science.gov (United States)

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

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

2012-10-01

34

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.

35

Five Kepler target stars that show multiple transiting exoplanet candidates  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-06-01

36

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.

37

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

38

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

39

Fractal characteristics of exoplanet transit time series data  

Science.gov (United States)

Exoplanet transit time series photometric data usually contain noise levels that are comparable to the transit signal jumps. The analysis that assumes Gaussian noise and extensive data averaging calibrated to a reference star has been the traditionally used algorithm. This paper studied the fractal property of the time series and found that the fractal dimension changes for time series data that contain transits. The Higuchi fractal method, where the length of the increment in various time lags is plotted against the lags, was used in this study. (Higuchi, T., "Approach to an irregular time series on the basis of fractal theory", Physica D, vol 31, 277-283, 1988). The fractal algorithm was calibrated with the Weierstrass function. Simulations using Gaussian noise suggested that a transit jump signal at about 1-sigma noise level would produce changes in fractal dimension, while non-Gaussian noise simulations suggested a higher transit jump signal. The fractal algorithm was applied to data collected on HD 209458 as well as on published data. The transit caused a fractal dimension change of about 0.06. An over-exposed CCD dataset with much noise was also analyzed and a fractal dimension change of about 0.02 was obtained. The result suggests that fractal dimension analysis, without the assumption of error normality, is an alternative method for identifying transits in time series photometric data.

Tremberger, George, Jr.; Yao, H.; Flamholz, A.; Cheung, E.; Marchese, P.; Cotten, D.; Lieberman, D. H.; Cheung, T. D.

2006-06-01

40

Cloud signatures in transit spectra of exoplanet atmospheres  

Science.gov (United States)

We present an analytical model for the transmission spectrum of a transiting exoplanet, extending previous models to incorporate condensation cloud base and top. We show that a cloud base (position where the cloud evaporates) 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 cloud- forming material (for a given cloud particle size); moreover, we can derive the abundance of the cloud constituent by measuring the magnitude of the inflection drop. 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 have applied the model to the transit spectrum of HD189733b, where we identify a possible inflection and examine its implications about the T-P profile of the atmosphere and the abundance of the candidate cloud material.

Vahidinia, Sanaz; Cuzzi, Jeff; Marley, Mark; Fortney, Jonathan

2014-11-01

 
 
 
 
41

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

Science.gov (United States)

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

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

2014-05-01

42

New Transiting Exoplanets: Targets of Opportunity for Spitzer's Legacy  

Science.gov (United States)

We propose a Target of Opportunity (ToO) program to observe photometric eclipses and transits of new extrasolar planets. The measurements constrain models of composition, chemistry, and atmospheric dynamics. We will populate a figure of predicted equillibrium vs. observed brightness temperature, which is starting to show a separate class of chemically-distinct planets. The events also inform follow-on work. As Spitzer's cryogen dwindles, rapid response is crucial. Well below Spitzer's nominal sensitivity, these measurements require optimized observing and analysis techniques. Our goals, begun with our Cycle-3 and -4 ToO programs and continued here, are to ensure that each bandpass is observed for every planet with good predicted S/N, to obtain the best possible observations, to make these high-impact data public for everyone to use in planning followups, and to make the process of observing exoplanets smooth for observers and Spitzer by allocating a predictable number of events for the community through the TAC process. Based on discovery statistics, 20-30 new transiting planets will be announced in 2008. Of these, 1-2 might be bright enough for six bandpasses, and many more will be observable in one or more IRAC bands. We thus request 120 hours to cover ~17 7:40-hour eclipse events in low-impact ToOs. This will cover 3-6 planets in all useful bands, depending on their brightnesses. We give criteria for activating ToOs, focusing on bright/unusual objects (eccentric, hot, cool, small, etc.). Our Legacy product is archivally-prepared calibrated lightcurves, submitted as electronic attachments with journal articles. Transiting extrasolar planets are among the least anticipated, most productive, and most publicly stimulating targets for Spitzer. These direct measurements provide the only emission fluxes possible with current telescopes for extrasolar planets, and stand as a Spitzer legacy for posterity. No comparable opportunity to observe exoplanets will be available until JWST.

Harrington, Joseph; Bakos, Gaspar; Deming, Drake; Fischer, Debra; Gillon, Michael; Iro, Nicolas; Laughlin, Gregory; Seager, Sara; Stevenson, Kevin; Wheatley, Peter

2008-03-01

43

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

44

The role of space telescopes in the characterization of transiting exoplanets  

Science.gov (United States)

Characterization studies now have a dominant role in the field of exoplanets. Such studies include the measurement of an exoplanet's bulk density, its brightness temperature and the chemical composition of its atmosphere. The use of space telescopes has played a key part in the characterization of transiting exoplanets. These facilities offer astronomers data of exquisite precision and temporal sampling as well as access to wavelength regions of the electromagnetic spectrum that are inaccessible from the ground. Space missions such as the Hubble Space Telescope, Microvariability and Oscillations of Stars (MOST), Spitzer Space Telescope, Convection, Rotation and Planetary Transits (CoRoT), and Kepler have rapidly advanced our knowledge of the physical properties of exoplanets and have blazed a trail for a series of future space missions that will help us to understand the observed diversity of exoplanets.

Hatzes, Artie P.

2014-09-01

45

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

46

Engaging Undergraduate Students in Transiting Exoplanet Research with Small Telescopes  

Science.gov (United States)

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

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

2013-10-01

47

Transmission spectrum of Venus as a transiting exoplanet  

CERN Document Server

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

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

2011-01-01

48

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

49

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

CERN Document Server

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

Griffith, Caitlin A

2013-01-01

50

An Efficient Automated Validation Procedure for Exoplanet Transit Candidates  

CERN Document Server

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

Morton, Timothy D

2012-01-01

51

Planetary transits from CoRoT-Europe and exoplanets  

Energy Technology Data Exchange (ETDEWEB)

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

Fridlund, C V M [European Space Agency, RSSD, ESTEC, Keplerlaan 1, NL-2200AG Noordwijk (Netherlands)], E-mail: malcolm.fridlund@esa.int

2008-08-15

52

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

53

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

54

Planetary transits from CoRoT-Europe and exoplanets  

International Nuclear Information System (INIS)

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

55

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

56

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

57

Detecting the Exoplanet Transits of HD 209458 and TrES-1  

Science.gov (United States)

There has been great interest in recent years in exoplanets and the stars which they orbit. Exoplanets are planets which orbit stars other than the Sun. Since the first exoplanet discovery in 1995, professional and amateur astronomers alike have been searching for planetary systems outside our solar system in hopes of someday finding one similar to Earth. We observed the transit of two planets, HD 209458b and TrES-1b, across their stars. These transits were detected using a CCD camera in order to obtain a light curve, a graph of the star's magnitude versus time, for the transit. Extensive use of the telescope and CCD camera located at the Winfree Observatory at Randolph-Macon Woman's College, along with camera software and image processing software, was essential to obtaining the light curves. The resulting light curves were compared to those of other ovservers in order to confirm the accuracy of our results.

Wellington, Tracey

2005-03-01

58

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

59

The "missing link": a 4-day period transiting exoplanet around OGLE-TR-111  

CERN Document Server

We report the discovery of a transiting hot Jupiter around OGLE-TR-111, from our radial velocity follow-up of OGLE transiting candidates in Carina. The planet has a mass of 0.53 +- 0.11 M_J and a radius of 1.0 +0.13-0.06 R_J. Three transiting exoplanets have already been found among OGLE candidates, all with periods near 1.5 days. The planet presented here, with P=4.0 days, is the first exoplanet detected by transits with the characteristics of a "normal" hot Jupiter, as found in abundance by radial velocity surveys The radius of OGLE-TR-111b and the scarcity of hot Jupiters detected among OGLE transit candidates tend to indicate that the case of HD209458b, with a radius of 1.4 R_J, is exceptional, with most hot Jupiters being smaller.

Pont, F; Queloz, D; Santos, N; Melo, C; Mayor, M; Udry, S; Pont, Frederic; Bouchy, Francois; Queloz, Didier; Santos, Nuno; Melo, Claudio; Mayor, Michel; Udry, Stephane

2004-01-01

60

CHEOPS: a space telescope for ultra-high precision photometry of exoplanet transits  

Science.gov (United States)

The CHaracterising ExOPlanet Satellite (CHEOPS) is a joint ESA-Switzerland space mission (expected to launch in 2017) dedicated to search for exoplanet transits by means of ultra-high precision photometry. CHEOPS will provide accurate radii for planets down to Earth size. Targets will mainly come from radial velocity surveys. The CHEOPS instrument is an optical space telescope of 30 cm clear aperture with a single focal plane CCD detector. The tube assembly is passively cooled and thermally controlled to support high precision, low noise photometry. The telescope feeds a re-imaging optic, which supports the straylight suppression concept to achieve the required Signal to Noise.

Fortier, Andrea; Beck, Thomas; Benz, Willy; Broeg, Christopher; Cessa, Virginie; Ehrenreich, David; Thomas, Nicolas

2014-08-01

 
 
 
 
61

A new powerful method for probing the atmospheres of transiting exoplanets  

CERN Document Server

Although atmospheric transmission spectroscopy of HD209458b with the Hubble Space Telescope has been very successful, attempts to detect its atmospheric absorption features using ground-based telescopes have so far been fruitless. Here we present a new method for probing the atmospheres of transiting exoplanets which may be more suitable for ground-based observations, making use of the Rossiter effect. During a transit, an exoplanet sequentially blocks off light from the approaching and receding parts of the rotating star, causing an artificial radial velocity wobble. The amplitude of this signal is directly proportional to the effective size of the transiting object, and the wavelength dependence of this effect can reveal atmospheric absorption features, in a similar way as with transmission spectroscopy. The advantage of this method over conventional atmospheric transmission spectroscopy is that it does not rely on accurate photometric comparisons of observations on and off transit, but instead depends on t...

Snellen, I

2004-01-01

62

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

63

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

64

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

65

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 su...

Sing, D. K.; Huitson, C. M.; Lopez-morales, M.; Pont, F.; De?sert, J. -m; Ehrenreich, D.; Wilson, P. A.; Ballester, G. E.; Fortney, J. J.; Etangs, A. Lecavelier Des; Vidal-madjar, A.

2012-01-01

66

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

67

Exploring the Diversity of Exoplanet Atmospheres Using Ground-Based Transit Spectroscopy  

Science.gov (United States)

This is a proposal to fund an observational study of the atmospheres of exoplanets in order to improve our understanding of the nature and origins of these mysterious worlds. The observations will be performed using our new approach for ground-based transit spectroscopy measurements that yields space-telescope quality data. We will also carry out supporting theoretical calculations with new abundance retrieval codes to interpret the measurements. Our project includes a survey of giant exoplanets, and intensive study of especially compelling exoplanets. For the survey, optical and near-infrared transmission spectra, and near-infrared emission spectra will be measured for giant exoplanets with a wide range of estimated temperatures, heavy element abundance, and mass. This comprehensive characterization of a large sample of these planets is now crucial to investigate such issues for their atmospheres as the carbon-to-oxygen ratios and overall metallicities, cause of thermal inversions, and prevalence and nature of high-altitude hazes. The intensive study of compelling individual planets will focus on low-mass (M JWST and a future TPF-like mission.

Bean, Jacob

68

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

CERN Document Server

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

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

2012-01-01

69

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.

70

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

71

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

Science.gov (United States)

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-shaped pupil mask coronagraph with general darkness constraints, a concentric ring mask considering the obscured pupil for surveying a wide field, and a spectral disperser for simultaneous wide wavelength coverage, and the first results of tests of the toughness of MEMS deformable mirrors for the rocket launch are introduced, together with a description of a passive wavefront correction mirror using no actuator.

Enya, K.; Abe, L.; Takeuchi, S.; Kotani, T.; Yamamuro, T.

2011-09-01

72

Investigating Close-in Exoplanets through Transit Observations  

CERN Document Server

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

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

2013-01-01

73

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

74

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

75

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

76

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

77

Estimating transiting exoplanet masses from precise optical photometry  

CERN Document Server

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

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

2011-01-01

78

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

CERN Document Server

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

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

2010-01-01

79

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

CERN Document Server

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

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

2013-01-01

80

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

Science.gov (United States)

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

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

2013-11-01

 
 
 
 
81

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

Science.gov (United States)

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

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

2014-06-01

82

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

83

A Smaller Radius for the Transiting Exoplanet WASP-10b  

CERN Document Server

We present photometry of WASP-10 during the transit of its short-period Jovian planet. We employed the novel PSF-shaping capabilities the OPTIC camera mounted on the UH 2.2m telescope to achieve a photometric precision of 4.7e-4 per 1.3 min sample. With this new light curve, in conjunction with stellar evolutionary models, we improve on existing measurements of the planetary, stellar and orbital parameters. We find a stellar radius Rstar = 0.698 +/- 0.012 Rsun and a planetary radius Rp = 1.080 +/- 0.020 Rjup. The quoted errors do not include any possible systematic errors in the stellar evolutionary models. Our measurement improves the precision of the planet's radius by a factor of 4, and revises the previous estimate downward by 16% (2.5sigma, where sigma is the quadrature sum of the respective confidence limits). Our measured radius of WASP-10b is consistent with previously published theoretical radii for irradiated Jovian planets.

Johnson, John A; Cabrera, Nicole E; Carter, Joshua A

2008-01-01

84

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.

85

H\\alpha\\ Absorption in Transiting Exoplanet Atmospheres  

CERN Document Server

Absorption of stellar H\\alpha\\ by the upper atmosphere of the planet HD189733b 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\\ ~ 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 laye...

Christie, Duncan; Li, Zhi-Yun

2013-01-01

86

Discovering Exoplanets with Microlensing: Transition to the Next Generation  

Science.gov (United States)

We propose to continue our successful program of planet discovery using the gravitaional microlensing technique. Our work will specifically focus on so-called "high- magnification events", which are exceptionally sensitive to planets, and which allow us to extract exceptionally detailed information about each planetary system. These results will be of high scientific interest in their own right, but will also play a key role in the transition to "next-generation" surveys that will discover many times more planets in "low-magnification events". We will continue to operate and build our network of approximately 30 amateur+professional astronomers (about half each) on 6 continents plus Oceania, which enables the 24 hour coverage that is crucial to extracting planetary science from microlensing events. In particular, by engaging the amateurs at a high scientific level, we will both improve the quantity and quality of amateur data and utilize their role as a "transmission belt" to the broader public. Over the past few years, high-mag events have enabled the first detection of a Jupiter- Saturn analog system, the first census of ice and gas giants beyond the snow line, the recognition that "cold Neptunes" are extremely common, and the detection of 3 very massive, super-Jupiter planets orbiting M dwarfs (which may challenge the standard "core-accretion" paradigm). Analysis of these events has also led to key theoretical insights, including the fact that planet orbital motion can be detected in microlensing events and that careful effort is required to disentangle this from "parallax effects" (due to the Earth's own orbital motion). The direct impact of our proposed work will be to increase the still small statistics of high-mag planet detections (due to the intrinsic rarity of high-mag events) and to exploit the sensitivity of these events to higher-order effects (including parallax, planet orbital motion, and multiple planets) to gain deeper knowledge of detected systems. Because microlensing sensitivity peaks at orbital radii of a few times the snow-line, it is complementary to other techniques that (like RV and transits) are most sensitive to planets that are closer in or that (like direct imaging) are sensitive to planets that are further out. But we also expect that this work will have tremendous indirect impact on the field, which is rapidly growing. In particular, high-mag events are the best means of training students and other junior people in the technically demanding skills required to model microlensing events. In fact, there are only a handful of people in the world capable of carrying out this analysis, while the number of events that will be discovered is likely to explode as new multi-site wide-angle surveys of low-mag events come on line. The disparity between planet discoveries and people to analyze them would increase even further if a satellite such as WFIRST were launched and had a significant microlensing component (the primary space recommendation of Astro2010). We note that ALL current workers in the field of planetary microlensing who obtained PhDs from US institutions in the last 15 years, were trained by our group at OSU. In addition, theoretical work on microlensing (such as the recognition of the relation of parallax and orbital motion) has largely been driven by the challenges posed by high-mag events, and we expect that this will remain so in the future. Finally, we note that, for technical reasons discussed in the proposal, high-mag events are the most robust candidates for space-based parallax measurements, which can pin down the mass and distance to the planet. This may develop into an important auxiliary application of solar-system missions that are in heliocentric orbit.

Gould, Andrew

87

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

CERN Document Server

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

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

2006-01-01

88

NStED: Exo-Planet Transit Survey TrES Lyr1  

Science.gov (United States)

The Trans-atlantic Exoplanet Survey (TrES) attempts to find planetary transits among bright stars. The two telescope used are the 10cm Sleuth Telescope (Palomar Observatory, California) and the 10cm Planet Search Survey Telescope (PSST) at Lowell Observatory, Arizona. The survey area covers 5.7 degrees by 5.7 degrees and is centered on the star 16 Lyr (19h 01m 26.3713s +46d 56m 05.325s). NStED provides access to high precision time-series photometry from stars observed by various transit survey programs. The data presented here are the result of the Lyra 1 campaign with TrES telescopes.

O'Donovan, Francis T.; Charbonneau, David; Mandushev, Georgi; Dunham, Edward W.; Latham, David W.; Torres, Guillermo; Sozzetti, Alessandro; Brown, Timothy M.; Trauger, John T.; Belmonte, Juan A.; Rabus, Markus; Almenara, José M.; Alonso, Roi; Deeg, Hans J.; Esquerdo, Gilbert A.; Falco, Emilio E.; Hillenbrand, Lynne A.; Roussanova, Anna; Stefanik, Robert P.; Winn, Joshua N.

89

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

90

Stellar Spectroscopy during Exoplanet Transits: Dissecting fine structure across stellar surfaces  

CERN Document Server

Differential spectroscopy during exoplanet transits permits to reconstruct spectra of small stellar surface portions that successively become hidden behind the planet. The center-to-limb behavior of stellar line shapes, asymmetries and wavelength shifts will enable detailed tests of 3-dimensional hydrodynamic models of stellar atmospheres, such that are required for any precise determination of abundances or seismic properties. Such models can now be computed for widely different stars but have been feasible to test in detail only for the Sun with its resolved surface structure. Although very high quality spectra are required, already current data permit reconstructions of line profiles in the brightest transit host stars such as HD209458 (G0 V).

Dravins, Dainis; Dahlén, Erik; Pazira, Hiva

2014-01-01

91

Emulating JWST/NIRCam 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 a transit measurement with a radial velocity measurement gives information about a planet's radius and mass, respectively, leading to an estimate of the planet's density and therefore to its composition and evolutionary history. 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. These 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). In our controlled laboratory experiment, we use a H2RG detector, two lamps of variable intensity, along with spectral line and photometric simulation masks to emulate the signals from a star-only, from a planet-only and finally, from a combination of a planet + star. Two masks have been used to simulate spectra in monochromatic light. The masks are 1040 pixels in length with one mask having a 2-pixel width and the other a 10-pixel width. From many-hour long observing sequences we obtain time series photometry with deliberate offsets introduced to test sensitivity to pointing jitter and other effects. We can modify the star- planet brightness contrast by factors up to 104:1. With cross correlation techniques we calculate positional shifts which are then used to decorrelate the effects of vertical and lateral offsets due to turbulence and instrumental vibrations on the photometry. Using Principal Component Analysis (PCA), we reject correlated temporal noise to achieve a precision lower than 50 ppm (Clanton et al 2012). 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-Lebreton, D.; Vasisht, G.; Smith, R.; Krist, J.; Beichman, C.

2014-03-01

92

The Exoplanet Orbit Database  

CERN Document Server

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

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

2010-01-01

93

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

94

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

Science.gov (United States)

Gas-giant planets emit a large fraction of their light in the mid-infrared (gsim3 ?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 ?m), which are the longest wavelengths currently accessible to ground-based, high-contrast imagers. We present binocular LBT adaptive optics (AO) images of the HR 8799 planetary system in six narrow-band filters from 3 to 4 ?m, and a Magellan AO image of the 2M1207 planetary system in a broader 3.3 ?m band. These systems encompass the five known exoplanets with luminosities consistent with L ? 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 (spanned by the narrow-band filters and encompassed by the broader 3.3 ?m filter). For 2M1207 b, we find that thick clouds and non-equilibrium chemistry caused by vertical mixing can explain the object's appearance. For the HR 8799 planets, we present new models that suggest the atmospheres must have patchy clouds, along with non-equilibrium chemistry. Together, the presence of a heterogeneous surface and vertical mixing presents a picture of dynamic planetary atmospheres in which both horizontal and vertical motions influence the chemical and condensate profiles.

Skemer, Andrew J.; Marley, Mark S.; 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

2014-09-01

95

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.

96

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

CERN Document Server

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

Burrows, Adam; Spiegel, David; Menou, Kristen

2010-01-01

97

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

98

Wideband Infrared Spectrometer for Characterization of Transiting Exoplanets with Space Telescopes  

CERN Document Server

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. The baseline design consists of two detectors, two prisms with a dichroic coating and microstructured grating surfaces, and three mirrors. Moving parts are not adopted. The effect of defocusing is evaluated for the case of a simple shift of the detector, and anisotropic defocusing to maintain the spectral resolving power. Variations in the design and its application to planned missions are also discussed.

Enya, Keigo

2012-01-01

99

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

100

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

CERN Document Server

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

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

2013-01-01

 
 
 
 
101

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

102

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

103

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

104

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

105

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

106

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

Science.gov (United States)

Colour-magnitude diagrams form a traditional way of presenting luminous objects in the Universe and compare them to each other. 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 absorbent within the 4.5 ?m band would reconcile outlying hot Jupiters with ultra-cool dwarfs' atmospheres. Measuring the emission of gas giants cooler than 1000 K would disentangle whether planets' atmospheres behave more similarly to brown dwarfs' atmospheres than to blackbodies, whether they are akin to the young directly imaged planets, or if irradiated gas giants form their own sequence.

Triaud, Amaury H. M. J.; Lanotte, Audrey A.; Smalley, Barry; Gillon, Michaël

2014-10-01

107

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

108

On constraining a transiting exoplanet's rotation rate with its transit spectrum  

CERN Document Server

We investigate the effect of planetary rotation on the transit spectrum of an extrasolar giant planet. During ingress and egress, absorption features arising from the planet's atmosphere are Doppler shifted by of order the planet's rotational velocity (~1-2 km/s) relative to where they would be if the planet were not rotating. We show that, in the case of HD209458b, this shift should give rise to a small net centroid shift of ~60 cm/s on the stellar absorption lines. Using a detailed model of the transmission spectrum due to a rotating star transited by a rotating planet with an isothermal atmosphere, we simulate the effect of the planet's rotation on the shape of the spectral lines, and in particular on the magnitude of their width and centroid shift. We then use this simulation to determine the expected signal-to-noise ratio for distinguishing a rotating from a non-rotating planet, and asses how this S/N scales with various parameters of HD209458b. We find that with a 6 m telescope, an equatorial rotational...

Spiegel, David S; Gaudi, B Scott

2007-01-01

109

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

110

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

Science.gov (United States)

In the core-accretion model, the nominal runaway gas-accretion phase brings most planets to multiple Jupiter masses. However, known giant planets are predominantly Jupiter mass bodies. Obtaining longer timescales for gas accretion may require using realistic equations of states, or accounting for the dynamics of the circumplanetary disk (CPD) in the low-viscosity regime, or both. Here we explore the second way by using global, three-dimensional isothermal hydrodynamical simulations with eight levels of nested grids around the planet. In our simulations, the vertical inflow from the circumstellar disk (CSD) to the CPD determines the shape of the CPD and its accretion rate. Even without a prescribed viscosity, Jupiter's mass-doubling time is ~104 yr, assuming the planet at 5.2 AU and a Minimum Mass Solar Nebula. However, we show that this high accretion rate is due to resolution-dependent numerical viscosity. Furthermore, we consider the scenario of a layered CSD, viscous only in its surface layer, and an inviscid CPD. We identify two planet-accretion mechanisms that are independent of the viscosity in the CPD: (1) the polar inflow—defined as a part of the vertical inflow with a centrifugal radius smaller than two Jupiter radii and (2) the torque exerted by the star on the CPD. In the limit of zero effective viscosity, these two mechanisms would produce an accretion rate 40 times smaller than in the simulation.

Szulágyi, J.; Morbidelli, A.; Crida, A.; Masset, F.

2014-02-01

111

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

Science.gov (United States)

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

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

2014-01-01

112

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

113

The Transit Light Curve Project. VIII. Six Occultations of the Exoplanet TrES-3  

CERN Document Server

We present photometry of the exoplanet host star TrES-3 spanning six occultations (secondary eclipses) of its giant planet. No flux decrements were detected, leading to 99%-confidence upper limits on the planet-to-star flux ratio of 0.00024, 0.0005, and 0.00086 in the i, z, and R bands respectively. The corresponding upper limits on the planet's geometric albedo are 0.30, 0.62, and 1.07. The upper limit in the i band rules out the presence of highly reflective clouds, and is only a factor of 2-3 above the predicted level of thermal radiation from the planet.

Winn, Joshua N; Shporer, Avi; Fernandez, Jose; Mazeh, Tsevi; Latham, David W; Charbonneau, David; Everett, Mark E

2008-01-01

114

Heavy Element Enrichment of a Jupiter-mass Protoplanet as a Function of Orbital Location  

CERN Document Server

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 (sigma) functions sigma=sigma_0*a^(-alpha) with alpha < 2, the accretion timescale is significantly longer at larger radial distances. Efficient accretion is limited to the first ~ 1E5 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 alpha = 1/2, 1, and 3/2. We show that a Jupiter-mass protoplanet can accrete 1 to 110 M_earth of heavy elements, depending on the disk properties. Our results explain the large variation in heavy element enrichment found in extra-solar giant planets. Since higher disk surface density is found to lead to larger heavy element...

Helled, R

2009-01-01

115

Discovery of a probable 4-5 Jupiter-mass exoplanet to HD 95086 by direct-imaging  

CERN Document Server

Direct imaging has just started the inventory of 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. We report here the discovery in L' (3.8 microns) images of a probable companion orbiting at 56 AU the young (10-17 Myr), dusty, and early-type (A8) star HD 95086. This discovery is based on observations with more than a year-time-lapse. Our first epoch clearly revealed the source at 10 sigma while our second epoch lacked good observing conditions hence yielding a 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 the companion to be comoving with the star, with a 3 sigma confidence level. The planetary nature of the source is reinforced by a non-detection in Ks...

Rameau, J; Lagrange, A -M; Boccaletti, A; Quanz, S P; Bonnefoy, M; Girard, J H; Delorme, P; Desidera, S; Klahr, H; Mordasini, C; Dumas, C; Bonavita, M; Meshkat, T; Bailey, V; Kenworthy, M

2013-01-01

116

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

117

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

118

The SOPHIE search for northern extrasolar planets III. A Jupiter-mass companion around HD 109246  

CERN Document Server

We report the detection of a Jupiter-mass planet discovered with the SOPHIE spectrograph mounted on the 1.93-m telescope at the Haute-Provence Observatory. The new planet orbits HD109246, a G0V star slightly more metallic than the Sun. HD109246b has a minimum mass of 0.77 MJup, an orbital period of 68 days, and an eccentricity of 0.12. It is placed in a sparsely populated region of the period distribution of extrasolar planets. We also present a correction method for the so-called seeing effect that affects the SOPHIE radial velocities. We complement this discovery announcement with a description of some calibrations that are implemented in the SOPHIE automatic reduction pipeline. These calibrations allow the derivation of the photon-noise radial velocity uncertainty and some useful stellar properties (vsini, [Fe/H], logR'HK) directly from the SOPHIE data.

Boisse, I; Santos, N C; Lovis, C; Bouchy, F; Hébrard, G; Arnold, L; Bonfils, X; Delfosse, X; Desort, M; Dìaz, R F; Ehrenreich, D; Forveille, T; Gallenne, A; Lagrange, A M; Moutou, C; Udry, S; Pepe, F; Perrier, C; Perruchot, S; Pont, F; Queloz, D; Santerne, A; Ségransan, D; Vidal-Madjar, A

2010-01-01

119

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 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.

120

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

 
 
 
 
121

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

Science.gov (United States)

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 (10MJup) 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. (Nymeyer, S. et al. [2011]. Astrophys. J. 742, 35) 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 with the fact that such large day-side fluxes can be obtained only if there is no rotation of the atmosphere. Additionally, we infer light curves of the planet for a full orbit in the two Warm Spitzer bandpassses for the two cases of rotation and discuss the observational differences.

Iro, N.; Maxted, P. F. L.

2013-11-01

122

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

CERN Document Server

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

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

2008-01-01

123

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this work is a detailed analysis of transit light curves from TrES-1 and TrES-2, obtained over a period of three to four years, in order to search for variabilities in observed mid-transit times and to set limits for the presence of additional third bodies. Using the IAC 80cm telescope, we observed transits of TrES-1 and TrES-2 over several years. Based on these new data and previously published work, we studied the observed light curves and searched for variation...

Rabus, M.; Deeg, H. J.; Alonso, R.; Belmonte, J. A.; Almenara, J. M.

2009-01-01

124

The Effect of Conjunctions on the Transit Timing Variations of Exoplanets  

CERN Document Server

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

Nesvorny, David

2014-01-01

125

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

126

WASP-37b: A 1.8 MJ EXOPLANET TRANSITING A METAL-POOR STAR  

International Nuclear Information System (INIS)

We report on the discovery of WASP-37b, a transiting hot Jupiter orbiting an mv = 12.7 G2-type dwarf, with a period of 3.577469 ± 0.000011 d, transit epoch T0 = 2455338.6188 ± 0.0006 (HJD; dates throughout the paper are given in Coordinated Universal Time (UTC)), and a transit duration 0.1304+0.0018-0.0017 d. The planetary companion has a mass Mp = 1.80 ± 0.17 MJ and radius Rp = 1.16+0.07-0.06 RJ, yielding a mean density of 1.15+0.12-0.15 ?J. From a spectral analysis, we find that the host star has M* = 0.925 ± 0.120 Msun, R* = 1.003 ± 0.053 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.

127

NASA's Missions for Exoplanet Exploration  

Science.gov (United States)

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

Unwin, Stephen

2014-05-01

128

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

129

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

CERN Document Server

We report five new transit epochs of the extrasolar planet OGLE-TR-111b, observed in the v-HIGH and Bessell I bands with the FORS1 and FORS2 at the ESO Very Large Telescope, between April and May 2008. The new transits have been combined with all previously published transit data for this planet to provide a new Transit Timing Variations (TTVs) analysis of its orbit. We discard TTVs with amplitudes larger than 1.5 minutes over a 4-year observation time baseline, in agreement with the recent result by Adams et al.(2010a). Dynamical simulations fully exclude the presence of additional planets in the system with masses greater than 1.3, 0.4 and 0.5 M_earth at the 3:2, 1:2, 2:1 resonances, respectively. We also place an upper limit of about 30 M_earth on the mass of potential second planets in the region between the 3:2 and 1:2 mean-motion resonances.

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

2011-01-01

130

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

CERN Document Server

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

Vidotto, A A; Helling, Ch

2010-01-01

131

The SOPHIE search for northern extrasolar planets. III. A Jupiter-mass companion around HD 109246  

Science.gov (United States)

We report the detection of a Jupiter-mass planet discovered with the SOPHIE spectrograph mounted on the 1.93-m telescope at the Haute-Provence Observatory. The new planet orbits HD 109246, a G0V star slightly more metallic than the Sun. HD 109246b has a minimum mass of 0.77 MJup, an orbital period of 68 days, and an eccentricity of 0.12. It is placed in a sparsely populated region of the period distribution of extrasolar planets. We also present a correction method for the so-called seeing effect that affects the SOPHIE radial velocities. We complement this discovery announcement with a description of some calibrations that are implemented in the SOPHIE automatic reduction pipeline. These calibrations allow the derivation of the photon-noise radial velocity uncertainty and some useful stellar properties (v sin i, [Fe/H], log R’HK) directly from the SOPHIE data. Based on observations made with the SOPHIE spectrograph on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS/OAMP), France (program 07A.PNP.CONS).RV tables (Tables C.1 and C.2) are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/523/A88

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

2010-11-01

132

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

2014-11-01

133

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

134

Radial velocity follow-up of CoRoT transiting exoplanets  

Directory of Open Access Journals (Sweden)

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

Deleuil M.

2011-02-01

135

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

136

Search for Carbon Monoxide in the Atmosphere of the Transiting Exoplanet HD 189733b  

Science.gov (United States)

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 sstarf)3.6 ?m = 0.1545 ± 0.0003, (Rp /R sstarf)4.5 ?m = 0.1557 ± 0.0003, (Rp /R sstarf)5.8 ?m = 0.1547 ± 0.0005, and (Rp /R sstarf)8 ?m = 0.1544 ± 0.0004. The high accuracy of the planet radii measurement allows the search for atmospheric molecular absorbers. Contrary to a previous analysis of the same data set, our study is robust against systematics and reveals that water vapor absorption at 5.8 ?m is not detected in this photometric data set. Furthermore, in the band centered around 4.5 ?m we find a hint of excess absorption with an apparent planetary radius ?Rp /R * = 0.00128 ± 0.00056 larger (2.3?) than the one measured simultaneously at 8 ?m. This value is 4? above what would be expected for an atmosphere where water vapor is the only absorbing species in the near-IR. This shows that an additional species absorbing around 4.5 ?m could be present in the atmosphere. Carbon monoxide (CO) being a strong absorber at this wavelength is a possible candidate and this may suggest a large CO/H2O ratio between 5 and 60.

Désert, Jean-Michel; Lecavelier des Etangs, Alain; Hébrard, Guillaume; Sing, David K.; Ehrenreich, David; Ferlet, Roger; Vidal-Madjar, Alfred

2009-07-01

137

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

138

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

139

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

140

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

 
 
 
 
141

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

142

STEREO TRansiting Exoplanet and Stellar Survey (STRESS) - I. Introduction and data pipeline  

Science.gov (United States)

The Solar TErrestrial RElations Observatory (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 multibaffle systems, to perform 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 h for HI-2), high precision, wide magnitude range (R mag: 4-12) and broad sky coverage (nearly 20 per cent for HI-1A alone and 60 per cent of the sky in the zodiacal region for all instruments combined) of this instrument place it in a region left largely devoid by other current projects. In this paper, we describe the semi-automated pipeline devised for reduction of the data, some of the interesting characteristics of the data obtained and data-analysis methods used, along with some early results.

Sangaralingam, Vinothini; Stevens, Ian R.

2011-12-01

143

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

144

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

145

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

146

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

147

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-06-01

148

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.

149

Constraining High-speed Winds in Exoplanet Atmospheres through Observations of Anomalous Doppler Shifts during Transit  

Science.gov (United States)

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

Miller-Ricci Kempton, Eliza; Rauscher, Emily

2012-06-01

150

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.

151

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

152

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

CERN Document Server

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

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

2013-01-01

153

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

154

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

155

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

156

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

CERN Document Server

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

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

2011-01-01

157

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

International Nuclear Information System (INIS)

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

158

The Fabra-ROA Baker-Nunn Camera at Observatori Astron\\`omic del Montsec: a wide-field imaging facility for exoplanet transit detection  

CERN Document Server

A number of Baker-Nunn Camera (BNC) were manufactured by Smithsonian Institution during the 60s as optical tracking systems for artificial satellites with optimal optical and mechanical specifications. One of them was installed at the Real Instituto y Observatorio de la Armada (ROA). We have conducted a profound refurbishment project of the telescope to be installed at Observatori Astron\\`omic del Montsec (OAdM). As a result, the BNC offers the largest combination of a huge FOV (4.4$\\deg$x4.4$\\deg$) and aperture (leading to a limiting magnitude of V$\\sim$20). These specifications, together with their remote and robotic natures, allows this instrument to face an observational program of exoplanets detection by means of transit technique with high signal-to-noise ratio in the appropiate magnitude range.

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

2009-01-01

159

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

160

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

 
 
 
 
161

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

162

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

CERN Document Server

Exoplanet transit and Doppler surveys discover many binary stars during their operation that can be used to conduct a variety of ancillary science. Specifically, eclipsing binary stars can be used to study the stellar mass-radius relationship and to test predictions of theoretical stellar evolution models. By cross-referencing 24 binary stars found in the MARVELS Pilot Project with SuperWASP photometry, we find two new eclipsing binaries, TYC 0272-00458-1 and TYC 1422-01328-1, which we use as case studies to develop a general approach to eclipsing binaries in survey data. TYC 0272-00458-1 is a single-lined spectroscopic binary for which we calculate a mass of the secondary and radii for both components using reasonable constraints on the primary mass through several different techniques. For a primary mass of M_1 = 0.92 +/- 0.1 M_solar, we find M_2 = 0.610 +/- 0.036 M_solar, R_1 = 0.932 +/- 0.076 R_solar and R_2 = 0.559 +/- 0.102 R_solar, and find that both stars have masses and radii consistent with model pr...

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

2011-01-01

163

WARM SPITZER PHOTOMETRY OF THE TRANSITING EXOPLANETS CoRoT-1 AND CoRoT-2 AT SECONDARY ECLIPSE  

International Nuclear Information System (INIS)

We measure secondary eclipses of the hot giant exoplanets CoRoT-1 at 3.6 and 4.5 ?m, and CoRoT-2 at 3.6 ?m, both using Warm Spitzer. We find that the Warm Spitzer mission is working very well for exoplanet science. For consistency of our analysis we also re-analyze archival cryogenic Spitzer data for secondary eclipses of CoRoT-2 at 4.5 and 8 ?m. We compare the total data for both planets, including optical eclipse measurements by the CoRoT mission, and ground-based eclipse measurements at 2 ?m, to existing models. Both planets exhibit stronger eclipses at 4.5 than at 3.6 ?m, which is often indicative of an atmospheric temperature inversion. The spectrum of CoRoT-1 is best reproduced by a 2460 K blackbody, due either to a high altitude layer that strongly absorbs stellar irradiance, or an isothermal region in the planetary atmosphere. The spectrum of CoRoT-2 is unusual because the 8 ?m contrast is anomalously low. Non-inverted atmospheres could potentially produce the CoRoT-2 spectrum if the planet exhibits line emission from CO at 4.5 ?m, caused by tidal-induced mass loss. However, the viability of that hypothesis is questionable because the emitting region cannot be more than about 30% larger than the planet's transit radius, based on the ingress and egress times at eclipse. An alternative possibility to account for the spectrum of CoRoT-2 is an additional opacity source that acts strongly at wavelengths less than 5 ?m, heating the upper atmosphere while allowing the deeper atmosphere seen at 8 ?m to remain cooler. We obtain a similar result as Gillon et al. for the phase of the secondary eclipse of CoRoT-2, implying an eccentric orbit with e cos(?) = -0.0030 ± 0.0004.

164

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

165

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

166

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

167

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

Science.gov (United States)

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

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

2013-04-01

168

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

169

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

With the rapid developments in the exoplanet field, more and more terrestrial exoplanets are being detected. Characterising their atmospheres using transit observations will become a key datum in the quest for detecting an Earth-like exoplanet. The atmospheric transmission spectrum of our Earth will be an ideal template for comparison with future exo-Earth candidates. By observing a lunar eclipse, which offers a similar configuration to that of an exoplanet transit, we have ...

Yan, Fei; Fosbury, Robert A. E.; Petr-gotzens, Monika G.; Zhao, Gang; Wang, Wei; Wang, Liang; Liu, Yujuan; Palle?, Enric

2014-01-01

170

Transiting Exoplanet Survey Satellite (TESS) Community Observer Program including the Science Enhancement Option Box (SEO Box) - 12 TB On-board Flash Memory for Serendipitous Science  

Science.gov (United States)

The Transiting Exoplanet Survey Satellite (TESS) will perform an all-sky survey in a low-inclination, low-Earth orbit. TESS's 144 GB of raw data collected each orbit will be stacked, cleaned, cut, compressed and downloaded. The Community Observer Program is a Science Enhancement Option (SEO) that takes advantage of the low-radiation environment, technology advances in flash memory, and the vast amount of astronomical data collected by TESS. The Community Observer Program requires the addition of a 12 TB "SEO Box” inside the TESS Bus. The hardware can be built using low-cost Commercial Off-The-Shelf (COTS) components and fits within TESS's margins while accommodating GSFC gold rules. The SEO Box collects and stores a duplicate of the TESS camera data at a "raw” stage ( 4.3 GB/orbit, after stacking and cleaning) and makes them available for on-board processing. The sheer amount of onboard storage provided by the SEO Box allows the stacking and storing of several months of data, allowing the investigator to probe deeper in time prior to a given event. Additionally, with computation power and data in standard formats, investigators can utilize data-mining techniques to investigate serendipitous phenomenon, including pulsating stars, eclipsing binaries, supernovae or other transient phenomena. The Community Observer Program enables ad-hoc teams of citizen scientists to propose, test, refine and rank algorithms for on-board analysis to support serendipitous science. Combining "best practices” of online collaboration, with careful moderation and community management, enables this `crowd sourced’ participatory exploration with a minimal risk and impact on the core TESS Team. This system provides a powerful and independent tool opening a wide range of opportunity for science enhancement and secondary science. Support for this work has been provided by NASA, the Kavli Foundation, Google, and the Smithsonian Institution.

Schingler, Robert; Villasenor, J. N.; Ricker, G. R.; Latham, D. W.; Vanderspek, R. K.; Ennico, K. A.; Lewis, B. S.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L. D.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Seager, S.; Torres, G.; Udry, S.; Winn, J. N.; Worden, S. P.

2010-01-01

171

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

172

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.

173

Spitzer’s Past and Future Exoplanet Legacy  

Science.gov (United States)

Spitzer initiated and revolutionized the field exoplanet atmosphere studies from the first secondary eclipse measurements announced in 2005. Since that time Spitzer has accrued a long list of compelling exoplanet findings, including: thermal phase curves for atmospheric dynamics and heat transport constraints; inference of clouds; evidence for thermal inversions; and suggestions of high C/O atmospheric ratios. Cold Spitzer continued an exoplanet legacy by: discovery of transits of 55 Cnc e; unique atmosphere insights either alone or in tandem with visible wavelength telescopes; and validation of Kepler small planet candidates via primary eclipse measurements at Spitzer wavelengths to rule out astrophysical false positives. The future of Spitzer’s exoplanet program remains bright via continued observations of warm and hot exoplanet transits, secondary eclipses, and thermal phase curves, including small planets via long-duration campaigns.

Seager, Sara

2014-01-01

174

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

175

First Temperate Exoplanet Sized Up  

Science.gov (United States)

Combining observations from the CoRoT satellite and the ESO HARPS instrument, astronomers have discovered the first "normal" exoplanet that can be studied in great detail. Designated Corot-9b, the planet regularly passes in front of a star similar to the Sun located 1500 light-years away from Earth towards the constellation of Serpens (the Snake). "This is a normal, temperate exoplanet just like dozens we already know, but this is the first whose properties we can study in depth," says Claire Moutou, who is part of the international team of 60 astronomers that made the discovery. "It is bound to become a Rosetta stone in exoplanet research." "Corot-9b is the first exoplanet that really does resemble planets in our solar system," adds lead author Hans Deeg. "It has the size of Jupiter and an orbit similar to that of Mercury." "Like our own giant planets, Jupiter and Saturn, the planet is mostly made of hydrogen and helium," says team member Tristan Guillot, "and it may contain up to 20 Earth masses of other elements, including water and rock at high temperatures and pressures." Corot-9b passes in front of its host star every 95 days, as seen from Earth [1]. This "transit" lasts for about 8 hours, and provides astronomers with much additional information on the planet. This is fortunate as the gas giant shares many features with the majority of exoplanets discovered so far [2]. "Our analysis has provided more information on Corot-9b than for other exoplanets of the same type," says co-author Didier Queloz. "It may open up a new field of research to understand the atmospheres of moderate- and low-temperature planets, and in particular a completely new window in our understanding of low-temperature chemistry." More than 400 exoplanets have been discovered so far, 70 of them through the transit method. Corot-9b is special in that its distance from its host star is about ten times larger than that of any planet previously discovered by this method. And unlike all such exoplanets, the planet has a temperate climate. The temperature of its gaseous surface is expected to be between 160 degrees and minus twenty degrees Celsius, with minimal variations between day and night. The exact value depends on the possible presence of a layer of highly reflective clouds. The CoRoT satellite, operated by the French space agency CNES [3], identified the planet after 145 days of observations during the summer of 2008. Observations with the very successful ESO exoplanet hunter - the HARPS instrument attached to the 3.6-metre ESO telescope at La Silla in Chile - allowed the astronomers to measure its mass, confirming that Corot-9b is indeed an exoplanet, with a mass about 80% the mass of Jupiter. This finding is being published in this week's edition of the journal Nature. Notes [1] A planetary transit occurs when a celestial body passes in front of its host star and blocks some of the star's light. This type of eclipse causes changes in the apparent brightness of the star and enables the planet's diameter to be measured. Combined with radial velocity measurements made by the HARPS spectrograph, it is also possible to deduce the mass and, hence, the density of the planet. It is this combination that allows astronomers to study this object in great detail. The fact that it is transiting - but nevertheless not so close to its star to be a "hot Jupiter" - is what makes this object uniquely well suited for further studies. [2] Temperate gas giants are, so far, the largest known group of exoplanets discovered. [3] The CoRoT (Convection, Rotation and Transits) space telescope was constructed by CNES, with contributions from Austria, Germany, Spain, Belgium, Brazil and the European Space Agency (ESA). It was specifically designed to detect transiting exoplanets and carry out seismological studies of stars. Its results are supplemented by observations with several ground-based telescopes, among them the IAC-80 (Teide Observatory), the Canada Fra

2010-03-01

176

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

177

The NASA Exoplanet Archive: Data Inventory Service  

Science.gov (United States)

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

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

2014-06-01

178

The Exoplanet Characterisation Observatory (EChO) : an ESA mission to characterize exoplanets  

Science.gov (United States)

The EChO mission is proposed in the frame of the European Space Agency/M3 Cosmic Vision program. Its main goal is to provide a spectroscopic characterization for a significant sample of exoplanets by transit spectroscopy. The results of the existing ground-based and space surveys on exoplanets count for more than 900 objects, with radius/semi-major axis/temperature spanning a large amplitude in a parameter space. Even if biased by the detection techniques, the current sample shows clearly that Solar System planets are not representative of the exoplanets diversity, and the next step in exoplanets study will be to characterize this diversity. EChO is a mission dedicated to give a chemical survey over a diverse sample of exoplanets, with repeated observations on a more restricted sample. During the 5 years mission posted at the L2, a predetermined sample of ~120 exoplanets will be repeatedly observed, from a reference sample of over 200. The observational technique of EChO is to use temporal variations to separate planetary light from parent star in primary transits, secondary eclipses and planet phase variations. By recording simultaneously a spectrum from 0.55 to 11 micron (0.4-16 micron goal), at a spectral resolution between 30 and 300, molecular detection and abundance retrieval from the main constituents of exoplanetary atmospheres (CH4, H2O, CO, CO2, etc.) will be obtained. Planetary categories will include in size Jupiters, Neptunes and Superearths, and in temperature from hot (> 1000 K) to temperate 300 K). On a limited sample of exoplanets, spatial and temporal variability will be accessible, addressing questions on thermal and chemical transport or weather questions. The question of the formation of exoplanets will be addressed from measurements of bulk and atmospheric chemical composition.

Drossart, Pierre; Hartogh, P.; Isaak, K.; Lovis, C.; Micela, G.; Ollivier, M.; Ribas, I.; Snellen, I.; Swinyard, B.; Tinetti, G.; Puig, L.; Linder, M.; EChO ESA Science Team; EChO ESA Study Team

2013-10-01

179

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

180

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

 
 
 
 
181

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

CERN Document Server

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

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

2008-01-01

182

Spectra as Windows into Exoplanet Atmospheres  

CERN Document Server

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

Burrows, Adam

2013-01-01

183

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

184

Modeling Exoplanet Transmission Spectra with Solar System Objects  

Science.gov (United States)

Light transmitted through the atmosphere of an extrasolar planet during a transit becomes encoded with information about the composition and structure of the exoplanet’s atmosphere. Transit transmission spectroscopy aims to extract this information through observations of the exoplanet’s wavelength-dependent transit depth. However, this practice often yields results with degenerate interpretations. For instance, a featureless transmission curve could suggest an atmosphere with a large mean molecular weight, high-altitude clouds, or it could simply suggest that the instruments making the measurements are not sensitive enough to detect any subtle spectral features. As the number of known exoplanets continues to grow, so does the importance of our ability to accurately characterize these exoplanets using methods such as transit transmission spectroscopy. Fortunately, the bodies in our own solar system can serve as laboratories to understand extrasolar planetary systems. We present a model that can transform solar occultation data into transmission spectra of the atmospheres of various bodies within our solar system. Using this model, we can improve our current interpretations of exoplanetary transmission spectra through observations well-studied solar system objects, as if they were exoplanets. The transformation from occultation to transit presents several challenges including those due to refraction, viewing geometry, and limb darkening. However, we show that it is possible to extract a wavelength-dependent, star-planet radius ratio and therefore a transmission spectrum from occultation data. This model is originally intended for use on Saturn and Titan utilizing occultations observed by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Spacecraft. However, it has the potential to be applied to other planets and satellites, even those exhibiting thin atmospheres such as Mars. As future missions such as TESS and JWST continue to emphasize the importance of exoplanet characterization, it is critical that we understand the potential of transit transmission spectroscopy.

Dalba, Paul A.; Muirhead, Philip Steven; Hedman, Matthew M.; Fortney, Jonathan J.; Nicholson, Philip D.

2014-06-01

185

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

186

THESIS: the terrestrial habitable-zone exoplanet spectroscopy infrared spacecraft  

Science.gov (United States)

THESIS, the Transiting Habitable-zone Exoplanet Spectroscopy Infrared Spacecraft, is a concept for a medium/Probe class exoplanet mission. Building on the recent Spitzer successes in exoplanet characterization, THESIS would extend these types of measurements to super-Earth-like planets. A strength of the THESIS concept is simplicity, low technical risk, and modest cost. The mission concept has the potential to dramatically advance our understanding of conditions on extrasolar worlds and could serve as a stepping stone to more ambitious future missions. We envision this mission as a joint US-European effort with science objectives that resonate with both the traditional astronomy and planetary science communities.

Swain, Mark R.; Vasisht, Gautam; Henning, Thomas; Tinetti, Giovanna; Beaulieu, Jean-Phillippe

2010-07-01

187

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

188

Thesis: A Combined-light Mission For Exoplanet Molecular Spectroscopy  

Science.gov (United States)

THESIS, the Transiting Habitable-zone Exoplanet Spectroscopy Infrared Spacecraft, is a concept for a MIDEX/Discovery class exoplanet mission. Building on the recent Spitzer and Hubble successes in exoplanet characterization and molecular spectroscopy, THESIS would extend these types of measurements to a large population of planets including non-transiting planets and super-Earths. The ability to acquire high-stability, spectroscopic data from the near-visible to the mid-infrared is a unique aspect of THESIS. A strength of the THESIS concept is simplicity low technical risk, and modest cost. By enabling molecular spectroscopy of exoplanet atmospheres, THESIS mission has the potential to dramatically advance our understanding of conditions on extrasolar worlds while serving as a stepping stone to more ambitious future missions.

Deroo, Pieter; Swain, M. R.; Tinetti, G.; Griffith, C.; Vasisht, G.; Deming, D.; Henning, T.; Beaulieu, J.

2010-01-01

189

New Features of the Exoplanet Orbit Database at Exoplanets.org  

Science.gov (United States)

We report a series of updates and enhancements on the Exoplanet Orbit Database (EOD), which contains peer-reviewed orbital and transit parameters of exoplanets and stellar parameters of their host stars. Along with inputting new planets, we regularly check the Astrophysics Data System and arXiv.org for updates to the orbits of known planets. Since December 2010, the EOD expanded from 427 planets to 640 planets, as of September 2012. The EOD can be explored through the Exoplanet Data Explorer Plotter and Table, available at http://exoplanets.org. Additions to the reported fields include stellar radius, asymmetric uncertainties, references for almost all parameters, and more. We are preparing to merge the EOD with data from the Exoplanet Archive's Kepler candidate list, and so have added many Kepler fields to the EOD including Kepler magnitude. This will allow for the confirmed exoplanets to be merged with Kepler candidates in the Exoplanet Data Explorers (EDE). We also plan to add microlensing and imaged planets, so that the entire population of high-quality, peer-reviewed planet detections can be displayed in the Table and Plotter EDEs. To minimize data entry errors in stellar parameters, a new program we wrote automatically retrieves fields like magnitudes, right ascension and declination, and the SAO identifier from SIMBAD data. We have also cross-examined our data with a few other independent databases to screen for typos and errors. We are also show fits of orbits of new and known planets of almost two dozen stars. Using the latest Keck velocities, we update solutions for several long period planets.

Feng, Ying; Han, E.; Wright, J.; Fakhouri, O.; Ford, E. B.; Planet Survey, California

2013-01-01

190

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

191

Atmospheric Circulation of Terrestrial Exoplanets  

Science.gov (United States)

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 Hadley circulation, wave adjustment of the thermal structure, and the tendency toward equatorial superrotation in the slowly rotating regime (the "tropics"). We then survey key elements of the hydrological cycle, including the factors that control precipitation, humidity, and cloudiness. Next, we summarize key mechanisms by which the circulation affects the global-mean climate, and hence planetary habitability. In particular, we discuss the runaway greenhouse, transitions to snowball states, atmospheric collapse, and the links between atmospheric circulation and CO2 weathering rates. We finish by summarizing the key questions and challenges for this emerging field in the future.

Showman, A. P.; Wordsworth, R. D.; Merlis, T. M.; Kaspi, Y.

192

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

193

Direct Detection of Exoplanets with Polarimetry  

Science.gov (United States)

The detection of scattered light from exoplanets gives direct access to the structure and composition of their atmospheres. Currently, most scattered light experiments focus on nearly edge-on, transiting systems. The temporal changes that occur during planetary occultations are used to suppress systematic errors that would otherwise overwhelm the planetary signal. However, linear polarimetry also has the potential to detect scattered light from exoplanets. This is because the polarization state of light scattered by a planetary atmosphere distinguishes it from both the direct light from the host star and the Wien tail of thermal re-radiation from the planet. Scattered flux should be identifiable regardless of orbital inclination, because both degree and position angle of polarization are modulated continuously throughout the orbit. Orbital inclination, mean number of scattering events, and scattering particle size and index of refraction are potentially discernable with polarimetry. I will report on the search for scattered light from known exoplanets using the POLISH2 polarimeter on the Lick 3-m telescope. This instrument simultaneously measures all four Stokes parameters (I, Q, U, and V), and it achieves precision at 2.5 times the photon shot noise limit over an entire observing run. The POLISH2 polarimeter is therefore ideally suited for direct detection of spatially unresolved exoplanets. This work is supported by a NExScI Sagan Fellowship, UC Lab Fees Research Grant, and UCO/Lick Observatory.

Wiktorowicz, Sloane

2013-01-01

194

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

195

Exoplanet detection capability of the COROT space mission  

CERN Document Server

COROT will be the first high precision photometric satellite to be launched with the aim of detecting exoplanets by the transit method. In this paper, we present the simulations we have carried out in order to assess the detection capability of COROT. Using the model of stellar population synthesis of the Galaxy developed at Besancon Observatory (Robin & Creze 1986) and a simple cross-correlation technique (Borde et al. 2001), we find that COROT has the capacity to detect numerous exoplanets, not only Jupiter and Uranus-class ones, but also hot terrestrial planets, if they exist. We show that small exoplanets should be mainly gathered around 14-15th magnitude K2-M2 dwarfs and giant exoplanets around 15-16th magnitude F7-G2 dwarfs. We study the effect of crowding and the impact of a high stellar variability noise that both reduce the detection capability of the instrument.

Bordé, P J; Léger, A

2003-01-01

196

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

197

ExELS: an exoplanet legacy science proposal for the ESA Euclid mission. II. Hot exoplanets and sub-stellar systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Exoplanet Euclid Legacy Survey (ExELS) proposes to determine the frequency of cold exoplanets down to Earth mass from host separations of ~1 AU out to the free-floating regime by detecting microlensing events in Galactic Bulge. We show that ExELS can also detect large numbers of hot, transiting exoplanets in the same population. The combined microlensing+transit survey would allow the first self-consistent estimate of the relative frequencies of hot and cold sub-stellar ...

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

2014-01-01

198

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

199

TEST - The Tautenburg Exoplanet Search Telescope  

CERN Document Server

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

Eigmüller, Philipp

2008-01-01

200

TEST The Tautenburg Exoplanet Search Telescope  

Science.gov (United States)

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

Eigmüller, Philipp; Eislöffel, Jochen

2009-02-01

 
 
 
 
201

Mass-radius relationships of rocky exoplanets  

CERN Document Server

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

Sohl, F; Rauer, H

2012-01-01

202

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

203

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

Science.gov (United States)

We propose a novel approach to utilize low-cadence photometric surveys for exoplanetary transit search. Even if transits are undetectable in the survey database alone, it can still be useful for finding preferred times for directed follow-up observations that will maximize the chances to detect transits [2].

Dzigan, Y.; Zucker, S.

2011-10-01

204

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

205

Exopop: Exoplanet population inference  

Science.gov (United States)

Exopop is a general hierarchical probabilistic framework for making justified inferences about the population of exoplanets. Written in python, it requires that the occurrence rate density be a smooth function of period and radius (employing a Gaussian process) and takes survey completeness and observational uncertainties into account. Exopop produces more accurate estimates of the whole population than standard procedures based on weighting by inverse detection efficiency.

Foreman-Mackey, Daniel

2014-07-01

206

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

CERN Document Server

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

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

2012-01-01

207

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

208

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

CERN Document Server

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

Dzigan, Yifat

2011-01-01

209

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

Science.gov (United States)

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

Dzigan, Yifat; Zucker, Shay

2011-08-01

210

Spectroscopy for Hot Super-Earth Exoplanets  

Science.gov (United States)

Spectroscopic observations of exoplanets are now possible by transit methods and direct emission. Spectroscopic requirements for exoplanet atmospheres will be reviewed based on existing measurements and model predictions for hot Jupiters and super-Earths. Super-Earths are exoplanets with masses in the range of about 2 to 10 Earth masses (i.e., between the size of Earth and Neptune). Many of them have very short orbital periods like hot Jupiters and are also hot because of proximity to their parent star. For example, Kepler-10b has a mass of 4.54 times that of Earth, a density of 8.74 g cm^{-3} and a surface temperature of 1833 K. More than thirty super-Earths have been discovered and the most interesting objects are rocky planets such as Kepler-10b and CoRoT-7b. Schaefer et al. have calculated the chemical equilibrium composition of super-Earths with temperatures in the range 500-4000 K based on the vaporization of silicate rocks similar to those of the Earth's continental crust and bulk silicate Earth. In addition to H_2O, CO_2, CH_4, CO and H_2 found in hot Jupiters, additional species such as SO_2, O_2, HCl, HF, NaCl, KCl, KF, KOH and NaOH are expected to be present. Similar to our previous work on hot ammonia and hot methane, emission spectra of hot SO_2 will be presented. Continuing work on NaCl and KCl emission spectra will also be covered. Hargreaves, R. J., Li, G., and Bernath, P. F. 2011, Hot NH_3 Spectra for Astrophysical Applications, Astrophys. J. 735, 111. Hargreaves, R. J., et al. 2012, Hot Methane Line Lists for Exoplanet and Brown Dwarf Atmospheres, Astrophys. J. 757, 46.

Bernath, P. F.; Dulick, M.

2013-06-01

211

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

212

Un-Earth-Like Interiors of Earth-Like Exoplanets  

Science.gov (United States)

Plate tectonics has played key roles in forming/modifying the surface environment of the Earth. Geophysical studies have shown that plate tectonics is linked to deep processes in the Earth and likely driven by convection in the deep mantle. Recent astrophysical survey (Bond et al., 2010) has shown large variations in key elemental ratios (such as Mg/Si) for planetary host stars. As Earth-like exoplanets may have the rocky mantles, composed mainly of magnesium silicates similar to the Earth, Mg/Si is of particular interest to understand the structure and dynamics of the solid parts of these exoplanets. The astrophysical data suggest that Mg/Si can vary between ~0.8 and ~2. Rocky exoplanets with Mg/Si~2 will have the mantles made almost entirely of olivine (Mg2SiO4) and its high-pressure polymorphs, while the mantles of rocky exoplanets with Mg/Si~1 will be made mostly of pyroxene (MgSiO3) and its high pressure polymorphs. The variation in mineralogy is significant considering that Earth's upper mantle is made of ~60% olivine and ~40% pyroxene. While the variation in mineralogy would not change the densities of the Earth-like exoplanets more than ~3%, it has profound consequences for the structure and convection in the mantle. For example, some rocky exoplanets with high Mg/Si may develop much more extensive melting at shallower depths in the mantle, resulting in different compositions and structures for their crusts compared with the Earth. In the opposite, extensive melting in some rocky exoplanets with low Mg/Si may be limited to the deep mantle. In Earth's mantle, high-pressure polymorphs of olivine and pyroxene undergo phase transitions to dense magnesium silicates and oxides in the lower mantle (~70% perovskite, MgSiO3, and ~30% periclase, MgO) at 660-km depth (Shim et al., 2001). Due to the high viscosity of MgSiO3 perovskite, the viscosity of the lower mantle is two orders of magnitude higher than the upper mantle in the Earth, affecting convection and chemical mixing. Because the viscosity of periclase (MgO) is much lower than perovskite (Ammann et al., 2011), some rocky exoplanets with high Mg/Si will have rheology of their lower mantles dominated by periclase, leading to much more vigorous convection in their mantles. These few examples suggest that variations in elemental abundances in rocky exoplanets can lead to very different compositions and processes in the solid part of the exoplanets, even if their densities are very similar to that of the Earth.

Shim, S.-H. D.

2014-03-01

213

Is This Speck of Light an Exoplanet?  

Science.gov (United States)

VLT Images and Spectra of Intriguing Object near Young Brown Dwarf [1] Summary Is this newly discovered feeble point of light the long-sought bona-fide image of an exoplanet? A research paper by an international team of astronomers [2] provides sound arguments in favour, but the definitive answer is now awaiting further observations. On several occasions during the past years, astronomical images revealed faint objects, seen near much brighter stars. Some of these have been thought to be those of orbiting exoplanets, but after further study, none of them could stand up to the real test. Some turned out to be faint stellar companions, others were entirely unrelated background stars. This one may well be different. In April of this year, the team of European and American astronomers detected a faint and very red point of light very near (at 0.8 arcsec angular distance) a brown-dwarf object, designated 2MASSWJ1207334-393254. Also known as "2M1207", this is a "failed star", i.e. a body too small for major nuclear fusion processes to have ignited in its interior and now producing energy by contraction. It is a member of the TW Hydrae stellar association located at a distance of about 230 light-years. The discovery was made with the adaptive-optics supported NACO facility [3] at the 8.2-m VLT Yepun telescope at the ESO Paranal Observatory (Chile). The feeble object is more than 100 times fainter than 2M1207 and its near-infrared spectrum was obtained with great efforts in June 2004 by NACO, at the technical limit of the powerful facility. This spectrum shows the signatures of water molecules and confirms that the object must be comparatively small and light. None of the available observations contradict that it may be an exoplanet in orbit around 2M1207. Taking into account the infrared colours and the spectral data, evolutionary model calculations point to a 5 jupiter-mass planet in orbit around 2M1207. Still, they do not yet allow a clear-cut decision about the real nature of this intriguing object. Thus, the astronomers refer to it as a "Giant Planet Candidate Companion (GPCC)" [4]. Observations will now be made to ascertain whether the motion in the sky of GPCC is compatible with that of a planet orbiting 2M1207. This should become evident within 1-2 years at the most. PR Photo 26a/04: NACO image of the brown dwarf object 2M1207 and GPCC PR Photo 26b/04: Near-infrared spectrum of the brown dwarf object 2M1207 and GPCC PR Photo 26c/04: Comparison between the possible 2M1207 system and the solar system Just a speck of light ESO PR Photo 26a/04 ESO PR Photo 26a/04 The Brown Dwarf Object 2M1207 and GPCC [Preview - JPEG: 400 x 471 pix - 65k] [Normal - JPEG: 800 x 942 pix - 158k] Caption: ESO PR Photo 26a/04 is a composite image of the brown dwarf object 2M1207 (centre) and the fainter object seen near it, at an angular distance of 778 milliarcsec. Designated "Giant Planet Candidate Companion" by the discoverers, it may represent the first image of an exoplanet. Further observations, in particular of its motion in the sky relative to 2M1207 are needed to ascertain its true nature. The photo is based on three near-infrared exposures (in the H, K and L' wavebands) with the NACO adaptive-optics facility at the 8.2-m VLT Yepun telescope at the ESO Paranal Observatory. Since 1998, a team of European and American astronomers [2] is studying the environment of young, nearby "stellar associations", i.e., large conglomerates of mostly young stars and the dust and gas clouds from which they were recently formed. The stars in these associations are ideal targets for the direct imaging of sub-stellar companions (planets or brown dwarf objects). The leader of the team, ESO astronomer Gael Chauvin notes that "whatever their nature, sub-stellar objects are much hotter and brighter when young - tens of millions of years - and therefore can be more easily detected than older objects of similar mass". The team especially focused on the study of the TW Hydrae Association. It is located in

2004-09-01

214

WASP-37b: A 1.8 M J exoplanet transiting a metal-poor star  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report on the discovery of WASP-37b, a transiting hot Jupiter orbiting an m v = 12.7 G2-type dwarf, with a period of 3.577469 ± 0.000011 d, transit epoch T 0 = 2455338.6188 ± 0.0006 (HJD; dates throughout the paper are given in Coordinated Universal Time (UTC)), and a transit duration 0.1304+0.0018,sub>0.0017 d. The planetary companion has a mass M p = 1.80 ± 0.17 M J and radius R p = 1.1...

Simpson, E. K.; Faedi, F.; Barros, S. C. C.; Brown, D. J. A.; Cameron, A. Collier; Hebb, L.; Pollacco, D.; Smalley, B.; Todd, I.; Butters, O. W.; He?brard, G.; Mccormac, J.; Miller, G. R. M.; Santerne, A.; Street, R. A.

2011-01-01

215

Exoplanets and their atmospheres  

International Nuclear Information System (INIS)

Full text: A decade of exoplanet search has led to surprising discoveries, from hot giant planets orbiting their star within a few days, to planets orbiting two Suns, extremely hot worlds with potentially permanent lava on their surfaces due to the star's proximity all the way to the first potential rocky worlds in the Habitable Zone of their stars. Observation techniques have now reached the sensitivity to explore the chemical composition of the atmospheres as well as physical structure of some detected planets. Nearly a thousand planets have already been detected around other Suns. The spectral fingerprint of light of planets gives us the key to explore them over light years away. (author)

216

EChO's view on gas giant exoplanets atmospheres  

CERN Document Server

The last decade has seen the discovery of more than a thousand exoplanets but, more excitingly, probing their atmospheres has become possible. With current data we caught a glimpse of the diversity of exoplanet atmospheres that will be revealed in the next years. However, numerous questions concerning their chemical composition, thermal structure, and atmospheric dynamics remain to be answered. More observations of higher quality are needed. The Exoplanet Characterisation Observatory (EChO) is a space-based observatory dedicated to the characterization of exoplanets atmospheres proposed to the ESA cosmic vision program. With its large spectral coverage (4-16 {\\mu}m) and high spectral resolution (\\Delta{\\lambda}/{\\lambda}>300 below 5 {\\mu}m and \\Delta{\\lambda}/{\\lambda}>30 above 5 {\\mu}m) EChO will provide spectrally resolved transit lightcurves, secondary eclipses lightcurves, and full phase curves of numerous exoplanets with an unprecedented signal to noise ratio. In this technical note we review some of tod...

Parmentier, Vivien; de Wit, Julien

2014-01-01

217

M Dwarf Flares: Exoplanet Detection Implications  

Science.gov (United States)

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

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

2011-12-01

218

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

219

Undercover Stars Among Exoplanet Candidates  

Science.gov (United States)

Very Large Telescope Finds Planet-Sized Transiting Star Summary An international team of astronomers have accurately determined the radius and mass of the smallest core-burning star known until now. The observations were performed in March 2004 with the FLAMES multi-fibre spectrograph on the 8.2-m VLT Kueyen telescope at the ESO Paranal Observatory (Chile). They are part of a large programme aimed at measuring accurate radial velocities for sixty stars for which a temporary brightness "dip" has been detected during the OGLE survey. The astronomers find that the dip seen in the light curve of the star known as OGLE-TR-122 is caused by a very small stellar companion, eclipsing this solar-like star once every 7.3 days. This companion is 96 times heavier than planet Jupiter but only 16% larger. It is the first time that direct observations demonstrate that stars less massive than 1/10th of the solar mass are of nearly the same size as giant planets. This fact will obviously have to be taken into account during the current search for transiting exoplanets. In addition, the observations with the Very Large Telescope have led to the discovery of seven new eclipsing binaries, that harbour stars with masses below one-third the mass of the Sun, a real bonanza for the astronomers. PR Photo 06a/05: Brightness "Dip" and Velocity Variations of OGLE-TR-122. PR Photo 06b/05: Properties of Low-Mass Stars and Planets. PR Photo 06c/05: Comparison Between OGLE-TR-122b, Jupiter and the Sun. The OGLE Survey When a planet happens to pass in front of its parent star (as seen from the Earth), it blocks a small fraction of the star's light from our view [1]. These "planetary transits" are of great interest as they allow astronomers to measure in a unique way the mass and the radius of exoplanets. Several surveys are therefore underway which attempt to find these faint signatures of other worlds. One of these programmes is the OGLE survey which was originally devised to detect microlensing events by monitoring the brightness of a very large number of stars over extended time intervals. During the past years, it has also included a search for periodic, very shallow "dips" in the brightness of stars, caused by the regular transit of small orbiting objects (small stars, brown dwarfs [2] or Jupiter-size planets). The OGLE team has since announced 177 "planetary transit candidates" from their survey of several hundred thousand stars in three southern sky fields, one in the direction of the Galactic Centre, another within the Carina constellation and the third within the Centaurus/Musca constellations. The nature of the transiting object can however only be established by subsequent radial-velocity observations of the parent star. The size of the velocity variations (the amplitude) is directly related to the mass of the companion object and therefore allows discrimination between stars and planets as the cause of the observed brightness "dip". A Bonanza of Low-Mass Stars An international team of astronomers [3] has made use of the 8.2-m VLT Kueyen telescope for this work. Profiting from the multiplex capacity of the FLAMES/UVES facility that permits to obtain high-resolution spectra of up to 8 objects simultaneously, they have looked at 60 OGLE transit candidate stars, measuring their radial velocities with an accuracy of about 50 m/s [4]. This ambitious programme has so far resulted in the discovery of five new transiting exoplanets (see, e.g., ESO PR 11/04 for the announcement of two of those). Most of the other transit candidates identified by OGLE have turned out to be eclipsing binaries, that is, in most cases common, small and low-mass stars passing in front of a solar-like star. This additional wealth of data on small and light stars is a real bonanza for the astronomers. Constraining the Relation Between Mass and Radius Low-mass stars are exceptionally interesting objects, also because the physical conditions in their interiors have much in common with those of giant planets, like Jupit

2005-03-01

220

Exoplanet Detection: Radial Velocity Method  

Science.gov (United States)

The Exoplanet Detection: The Radial Velocity Method model simulates the detection of exoplanets by using the radial velocity method and the Doppler effect. In this simulation the exoplanet orbits the star (sun-sized) in circular motion via Kepler's third law.  The radial velocity of the star is determined from the velocity of the exoplanet.  This velocity is then used to calculate the Doppler shift of the Fraunhofer lines of the star.  In practice it is the Doppler shift of the Fraunhofer lines of the star that are detected and from this the radial velocity is inferred.  From this the mass and orbital period and average exoplanet-star separation are determined.  In the simulation the star-exoplanet system is shown as seen from Earth (edge on view) and from space (overhead view), and with the star and exoplanet sizes not shown to the scale of the orbit.  In addition, the Fraunhofer lines are shown.  The radial velocites of stars are such that the Doppler shifts are small, to compensate you may snap to the Na line and use the right-hand side slider to zoom in on that line to see wavelength shift.  The mass of the exoplanet (relative to the mass of Jupiter), the average star-exoplant separation (in AU), and the inclination of the system relative to Earth can be changed. The simulation uses Java 3D, if installed, to render the view the star and exoplanet. If Java 3D is not installed, the simulation will default to simple 3D using Java.

Belloni, Mario

2010-06-29

 
 
 
 
221

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

222

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

223

The NASA/IPAC/NExScI Star and Exoplanet Database  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The NASA/IPAC/NExScI Star and Exoplanet Database (NStED) is a general purpose stellar archive which supports NASA planet-finding and planet-characterization goals, stellar astrophysics, and the planning of NASA and other space missions. There are two principal components of NStED: a database of 140,000 nearby stars and exoplanet-hosting stars, and an archive dedicated to high precision photometric surveys for transiting exoplanets (NStED-ETSS). We present summaries of these ...

Berriman, G. B.; Ali, B.; Baker, R.; Von Braun, K.; Chiu, N-m; Ciardi, D. R.; Good, J.; Kane, S. R.; Kong, M.; Laity, A. C.; Mcelroy, D. L.; Monkewitz, S.; Payne, A. N.; Ramirez, S.; Schmitz, M.

2009-01-01

224

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

225

Exploring Exoplanet Populations with NASA's Kepler Mission  

CERN Document Server

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 three years of data, 100 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 wit...

Batalha, Natalie M

2014-01-01

226

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

227

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 three years of data, 100 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 1 AU of their host stars in support of NASA's long-term goal of finding habitable environments beyond the solar system.

Batalha, N. M.

2014-09-01

228

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

2014-09-01

229

Coreless Terrestrial Exoplanets  

CERN Document Server

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

Elkins-Tanton, L

2008-01-01

230

Results from the Exoplanet Search Programmes with BEST and TEST  

CERN Document Server

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

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

2006-01-01

231

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

232

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

233

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

234

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 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

235

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

236

Exoplanet Characterization With Spitzer Eclipses  

Science.gov (United States)

We will analyze our existing Spitzer eclipse data for 11 exoplanets (GJ 436b, WASP-8b, WASP-29b, WASP-11b, TrES-1, WASP-34b, WASP-43b, HD 209458b, HAT-P-30b, HAT-P-13b, and WASP-12b) along with all other Spitzer eclipse and transit data for these systems (723 hours of total data). In combination with transit results, these measurements reveal the surface fluxes emitted by the planets' atmospheres in the six Spitzer bandpasses (3.6, 4.5, 5.8, 8.0, 16, and 24 1-4m), as well as orbital eccentricity and in a few cases possibly even precession rate. The fluxes, in turn, can constrain atmospheric composition and thermal profiles. We propose here to analyze data for these planets using Monte Carlo-driven, radiative-transfer, model-fitting codes; to conduct aggregate analyses; and to develop and share statistical modeling tools. Secondary eclipses provide us with a unique way to characterize exoplanetary atmospheres. Since other techniques like spectroscopy divide the planetary signal into many channels, they require very high signal-to-noise ratio (S/N) and are only possible for a few planets. Broadband eclipse photometry is thus the only technique that can measure dozens of atmospheres and identify the mechanisms that cause planets at a given irradiation level to behave so differently from one another. Until JWST becomes available, the broad variety of Spitzer data that we already have in hand, along with observations from the Hubble Space Telescope and possibly SOFIA, are our best way to understand the wide diversity of exoplanetary atmospheres. Since 2010, the team has produced six papers from a new, highly modular pipeline that implements optimal methods for analysis of Spitzer photometric time series, and our efficiency is increasing. The sensitivity needed for these measurements is up to 100 times better than Spitzer's design criteria, so careful treatment of systematic error is critically important and first-order approximations rarely work. The new pipeline attempts about 50 different analyses per observation, permuting different photometry aperture sizes, centering methods, and systematic models to find the best according to the standard deviation of normalized residuals and the Akaike and Bayesian Information Criteria. As a demonstration of its ease of use, two undergraduates have recently led papers based on the pipeline. The team now seeks funds for graduate student Patricio Cubillos, who is already trained and working (e.g., Cubillos et al. 2011). He will lead 1-2 secondary eclipse papers per year, based on our recent output. Three undergraduates will handle routine tasks and produce between them about one paper per year. The PI and a programmer are also supported. Our long-term goal is to produce a statistical sample of exoplanet secondary eclipses at wavelengths inaccessible to facilities other than Spitzer. These measure properties of exoplanetary atmospheres and orbits. Each planet is of significant intrinsic interest. In addition, an aggregate plot of planetary brightness vs. equilibrium temperature shows a significant jump in brightness near 2000 K. We will explore this and other results of aggregation, such as why some hot planets do or do not have thermal inversions, and under what circumstances photochemistry is important. There will be three main products from this grant: 1. Secondary eclipse analyses for 11 planets, including assessment of inversions, abundances, and thermal profiles. 2. Aggregate data analyses related to the brightness jump, which planets have thermal inversions and disequilibrium chemistry, and whether stellar metallicity, surface gravity, etc., affect the emitted fluxes. 3. Statistical enhancements to our open-source code for retrieving atmospheric composition and thermal profiles from eclipse data, using the method of Madhusudhan and Seager.

Harrington, Joseph

237

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

238

ExELS: an exoplanet legacy science proposal for the ESA Euclid mission. II. Hot exoplanets and sub-stellar systems  

CERN Document Server

The Exoplanet Euclid Legacy Survey (ExELS) proposes to determine the frequency of cold exoplanets down to Earth mass from host separations of ~1 AU out to the free-floating regime by detecting microlensing events in Galactic Bulge. We show that ExELS can also detect large numbers of hot, transiting exoplanets in the same population. The combined microlensing+transit survey would allow the first self-consistent estimate of the relative frequencies of hot and cold sub-stellar companions, reducing biases in comparing "near-field" radial velocity and transiting exoplanets with "far-field" microlensing exoplanets. The age of the Bulge and its spread in metallicity further allows ExELS to better constrain both the variation of companion frequency with metallicity and statistically explore the strength of star-planet tides. We conservatively estimate that ExELS will detect ~4100 sub-stellar objects, with sensitivity typically reaching down to Neptune-mass planets. Of these, ~600 will be detectable in both Euclid's V...

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

2014-01-01

239

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

CERN Document Server

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 paper, we elaborate on, and calculate, probabilities of secondary eclipses for given orbital parameters, both in the presence and absence of detected primary transits, and tabulate these values for the forty planets with the highest primary transit probabilities.

von Braun, Kaspar

2009-01-01

240

Modelling exoplanet atmospheres  

Science.gov (United States)

While the number of known extrasolar planets is steadily increasing recent years have shown the beginning of a new phase of our understanding of exoplanets due to the spectroscopic determi-nation of their atmospheric composition. Atmospheres of hot extrasolar giant gas planets have already been investigated by UV, optical and IR spectroscopy today. In future, spectroscopy of large, terrestrial planets ("super-Earth"), in particular planets in the habitable zone of their parent star, will be a major goal of investigation. Planning future space satellite observations of super-Earths requires modelling of atmospheres of terrestrial planets in different environments, such as e.g. central star type, orbital distance, as well as different atmospheric compositions. Whether planets able to support life "as we know it" exist outside our solar system is one of the most profound questions today. It can be addressed by characterizing the atmospheres of ter-restrial extrasolar planets searching for spectroscopic absorption bands of biomarker molecules. An overview of expected planetary conditions in terms of their habitability will be presented for several model scenarios of terrestrial extrasolar planets.

Rauer, Heike

 
 
 
 
241

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

242

Broadband Eclipse Spectra of Exoplanets are Featureless  

CERN Document Server

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

Hansen, C J; Cowan, N B

2014-01-01

243

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

Directory of Open Access Journals (Sweden)

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

Rauer H.

2011-02-01

244

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

CERN Document Server

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

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

2011-01-01

245

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

246

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

247

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

CERN Document Server

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

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

2013-01-01

248

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

249

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 <10 hr for Jovian 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

250

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

251

VLT Detects First Superstorm on Exoplanet  

Science.gov (United States)

Astronomers have measured a superstorm for the first time in the atmosphere of an exoplanet, the well-studied "hot Jupiter" HD209458b. The very high-precision observations of carbon monoxide gas show that it is streaming at enormous speed from the extremely hot day side to the cooler night side of the planet. The observations also allow another exciting "first" - measuring the orbital speed of the exoplanet itself, providing a direct determination of its mass. The results appear this week in the journal Nature. "HD209458b is definitely not a place for the faint-hearted. By studying the poisonous carbon monoxide gas with great accuracy we found evidence for a super wind, blowing at a speed of 5000 to 10 000 km per hour" says Ignas Snellen, who led the team of astronomers. HD209458b is an exoplanet of about 60% the mass of Jupiter orbiting a solar-like star located 150 light-years from Earth towards the constellation of Pegasus (the Winged Horse). Circling at a distance of only one twentieth the Sun-Earth distance, the planet is heated intensely by its parent star, and has a surface temperature of about 1000 degrees Celsius on the hot side. But as the planet always has the same side to its star, one side is very hot, while the other is much cooler. "On Earth, big temperature differences inevitably lead to fierce winds, and as our new measurements reveal, the situation is no different on HD209458b," says team member Simon Albrecht. HD209458b was the first exoplanet to be found transiting: every 3.5 days the planet moves in front of its host star, blocking a small portion of the starlight during a three-hour period. During such an event a tiny fraction of the starlight filters through the planet's atmosphere, leaving an imprint. A team of astronomers from the Leiden University, the Netherlands Institute for Space Research (SRON), and MIT in the United States, have used ESO's Very Large Telescope and its powerful CRIRES spectrograph to detect and analyse these faint fingerprints, observing the planet for about five hours, as it passed in front of its star. "CRIRES is the only instrument in the world that can deliver spectra that are sharp enough to determine the position of the carbon monoxide lines at a precision of 1 part in 100 000," says another team member Remco de Kok. "This high precision allows us to measure the velocity of the carbon monoxide gas for the first time using the Doppler effect." The astronomers achieved several other firsts. They directly measured the velocity of the exoplanet as it orbits its home star. "In general, the mass of an exoplanet is determined by measuring the wobble of the star and assuming a mass for the star, according to theory. Here, we have been able to measure the motion of the planet as well, and thus determine both the mass of the star and of the planet," says co-author Ernst de Mooij. Also for the first time, the astronomers measured how much carbon is present in the atmosphere of this planet. "It seems that H209458b is actually as carbon-rich as Jupiter and Saturn. This could indicate that it was formed in the same way," says Snellen. "In the future, astronomers may be able to use this type of observation to study the atmospheres of Earth-like planets, to determine whether life also exists elsewhere in the Universe." More information This research was presented in a paper that appears this week in the journal Nature: "The orbital motion, absolute mass, and high-altitude winds of exoplanet HD209458b", by I. Snellen et al. The team is composed of Ignas A. G. Snellen and Ernst J. W. de Mooij, (Leiden Observatory, The Netherlands), Remco J. de Kok (SRON, Utrecht, The Netherlands), and Simon Albrecht (Massachusetts Institute of Technology, USA). ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, Fr

2010-06-01

252

Near-IR Spectroscopy of the Hottest Known Exoplanet, WASP-33b  

Science.gov (United States)

We propose to use the WFC3 G141 grism to measure the near-IR thermal spectrum {1.1-1.7 microns} of the transiting exoplanet WASP-33b. WASP-33b is the most strongly irradiated and hottest known exoplanet, and it is key to testing hypotheses on the origin of temperature inversions in the atmospheres of giant hot exoplanets. Moreover, it orbits an A-type star whose spectrum is quite different from most planet-hosting stars. Consequently, the existence or non-existence of a temperature inversion in this planet is key to understanding what are the principal wavelengths where stellar irradiance drives the inversion process. The observational signature of an inversion in WASP-33b will be the presence of the strong 1.4-micron water band in emission, rather than in absorption as for non-inverted exoplanets. That signature will be very clear and obvious in our high-precision spectroscopy of this scorching world, and there will be no degeneracies in the interpretation. Our observations will span the time of secondary eclipse for this transiting system. We will use a ratioing technique - proven by our ongoing Cycle-18 program - to cancel instrumental errors and achieve photon-limited precision for the spectroscopy. We propose utilizing the new WFC3 driftscan capability to collect vast numbers of stellar photons from this bright {V= 8.3} system with high observing efficiency. Our observations will thereby produce some of the most precise exoplanet spectroscopy ever achieved.

Deming, Drake

2011-10-01

253

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

Science.gov (United States)

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

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

2014-01-01

254

Signals of exomoons in averaged light curves of exoplanets  

CERN Document Server

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

Simon, A E; Kiss, L L; Szatmáry, K

2011-01-01

255

The Exoplanet Eccentricity Distribution from Kepler Planet Candidates  

CERN Document Server

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

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

2012-01-01

256

Design and performance of the Exo-planet Characterisation Observatory (EChO) integrated payload  

Science.gov (United States)

The Exoplanet Characterisation Observatory (EChO) mission was one of the proposed candidates for the European Space Agency's third medium mission within the Cosmic Vision Framework. EChO was designed to observe the spectra from transiting exoplanets in the 0.55-11 micron band with a goal of covering from 0.4 to 16 microns. The mission and its associated scientific instrument has now undergone a rigorous technical evaluation phase and we report here on the outcome of that study phase, update the design status and review the expected performance of the integrated payload and satellite.

Swinyard, Bruce; Tessenyi, Marcel; Tinetti, Giovanna; Waldmann, Ingo; Eccleston, Paul; Ferlet, Marc; Irshad, Ranah; Lim, Tanya; Middleton, Kevin; Bradshaw, Tom; Crook, Martin; Hunt, Tom; Winter, Berend; Bryson, Ian; Bezawada, Naidu; Taylor, William; Bowles, Neil; Pascale, Enzo; Morgante, Gianluca; Pace, Emanuele; Adriani, Alberto; Reess, Jean-Michel; Drossart, Pierre; Coudé du Foresto, Vincent; Ollivier, Marc; Ottensamer, Roland; Rataj, Mirek; Ramos Zapata, Gonzalo; Schrader, Jan-Rutger; Selig, Avri; Isaak, Kate; Linder, Martin; Puig, Ludovic; Hartogh, Paul; Lovis, Christophe; Micela, Giusi; Ribas, Ignasi; Snellen, Ignas; Beaulieu, Jean-Phillippe

2014-08-01

257

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

258

High-precision ground-based photometry of exoplanets  

Science.gov (United States)

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

de Mooij, Ernst J. W.; Jayawardhana, Ray

2013-04-01

259

Modelling the transmission spectrum of the Earth as an exoplanet .  

Science.gov (United States)

Modelling the transmission spectra of exoplanets can provide us some crucial information on the relative abundances of the most prominent elements in their atmospheres. We use a simple one-slab model to generate synthetic spectra to fit the observations of the Earth's atmosphere transmission spectrum obtained during the lunar eclipse of 2008. As input molecular line lists we use the HITRAN database with the last updates from 2012. The observational data reflect a picture of the whole atmosphere that is similar to the situation of an exoplanetary transit. In the present work we conclude that this technique can be used in investigations of exoplanetary atmospheres.

Polinovskyi, G.; Pavlenko, Ya. V.; Martin, E. L.

260

Resource Letter Exo-1: Exoplanets  

Science.gov (United States)

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

Perryman, Michael

2014-06-01

 
 
 
 
261

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

262

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

263

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.

Burrows, Adam S.

2014-09-01

264

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

265

Doppler Imaging of Exoplanets and Brown Dwarfs  

Science.gov (United States)

Doppler Imaging produces 2D global maps. When applied to cool planets or more massive brown dwarfs, it can map atmospheric features and track global weather patterns. The first substellar map, of the 2pc-distant brown dwarf Luhman 16B (Crossfeld et al. 2014), revealed patchy regions of thin & thick clouds. Here, I investigate the feasibility of future Doppler Imaging of additional objects. Searching the literature, I find that all 3 of P, v sin i, and variability are published for 22 brown dwarfs. At least one datum exists for 333 targets. The sample is very incomplete below ~L5; we need more surveys to find the best targets for Doppler Imaging! I estimate limiting magnitudes for Doppler Imaging with various hi-resolution near-infrared spectrographs. Only a handful of objects - at the M/L and L/T transitions - can be mapped with current tools. Large telescopes such as TMT and GMT will allow Doppler Imaging of many dozens of brown dwarfs and the brightest exoplanets. More targets beyond type L5 likely remain to be found. Future observations will let us probe the global atmospheric dynamics of many diverse objects.

Crossfield, I.; Biller, B.; Schlieder, J.; Deacon, N.; Bonnefoy, M.; Homeier, D.; Allard, F.; Buenzli, E.; Henning, T.; Brandner, W.; Goldman, Bertr; Kopytova, T.

2014-03-01

266

PlanetPack software tool for exoplanets detection: coming new features  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We briefly overview the new features of PlanetPack2, the forthcoming update of PlanetPack, which is a software tool for exoplanets detection and characterization from Doppler radial velocity data. Among other things, this major update brings parallelized computing, new advanced models of the Doppler noise, handling of the so-called Keplerian periodogram, and routines for transits fitting and transit timing variation analysis.

Baluev, Roman V.

2014-01-01

267

Theoretical Spectra of Terrestrial Exoplanet Surfaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigate spectra of airless rocky exoplanets with a theoretical framework that self-consistently treats reflection and thermal emission. We find that a silicate surface on an exoplanet is spectroscopically detectable via prominent Si-O features in the thermal emission bands of 7 - 13 \\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

268

Non-Keplerian Dynamics of Exoplanets  

Science.gov (United States)

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

Fabrycky, D. C.

269

The McDonald Observatory Exoplanet Program  

Science.gov (United States)

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

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

2012-01-01

270

Transits of Earth-Like Planets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

271

TrES-1: The Transiting Planet of a Bright K0V Star  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report the detection of a transiting Jupiter-sized planet orbiting a relatively bright (V=11.79) K0V star. We detected the transit light-curve signature in the course of the TrES multi-site transiting planet survey, and confirmed the planetary nature of the companion via multicolor photometry and precise radial velocity measurements. We designate the planet TrES-1; its inferred mass is 0.75 +/- 0.07 Jupiter masses, its radius is 1.08 (+0.18/-0.04) Jupiter radii, and its o...

Alonso, Roi; Brown, Timothy M.; Torres, Guillermo; Latham, David W.; Sozzetti, Alessandro; Mandushev, Georgi; Belmonte, Juan A.; Charbonneau, David; Deeg, Hans J.; Dunham, Edward W.; O Donovan, Francis T.; Stefanik, Robert P.

2004-01-01

272

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)

273

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

274

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.

275

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

276

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

277

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

278

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

Science.gov (United States)

We present the SPICA Coronagraphic Instrument (SCI), which has been designed for a concentrated study of extra-solar planets (exoplanets). SPICA mission provides us with a unique opportunity to make high contrast observations because of its large telescope aperture, the simple pupil shape, and the capability for making infrared observations from space. The primary objectives for the SCI are the direct coronagraphic detection and spectroscopy of Jovian exoplanets in infrared, while the monitoring of transiting planets is another important target. The specification and an overview of the design of the instrument are shown. In the SCI, coronagraphic and non-coronagraphic modes are aplicable for both an imaging and a spectroscopy. The core wavelength range and the goal contrast of the coronagraphic mode are 3.5-27 ?m, and 10 -6, respectively. Two complemental designs of binary shaped pupil mask coronagraph are presented. The SCI has capability of simultaneous observations of one target using two channels, a short channel with an InSb detector and a long wavelength channel with a Si:As detector. We also give a report on the current progress in the development of key technologies for the SCI.

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

2011-07-01

279

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

280

Testing the paradigm of X-ray driven exoplanet evaporation with XMM+HST  

Science.gov (United States)

HST observations show that two of the brightest transiting exoplanets are evaporating {HD209458b & HD189733b} and models suggest that the evolution of close-in planets may be dominated by this mass loss. It is believed that the evaporation is driven by X-ray irradiation of the planet by its parent star, but a lack of simultaneous measurements of irradiation and evaporation prevents a meaningful test of this model. We propose simultaneous XMM-Newton and HST observations of three transits of the brightest X-ray source, HD189733, in order to test the paradigm of X-ray driven evaporation and make a direct measurement of the efficiency of exoplanet evaporation.

Wheatley, Peter

2012-10-01

 
 
 
 
281

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

282

ESPRI - Exoplanet Search with PRIMA  

Science.gov (United States)

ESPRI will use the PRIMA facility of the Very Large Telescope Interferometer to determine astrometric orbits of planets already known from radial-velocity surveys, and to search for new planets around stars that are not suitable for precise radial-velocity measurements. The ESPRI consortium has built and delivered the differential delay lines of PRIMA. Commissioning of this facility is currently proceeding at Cerro Paranal in Chile. The ESPRI consortium is also responsible for the astrometric data reduction pipeline, and for the development of observing and calibration strategies. In return, the ESPRI team will get guaranteed observing time for an exoplanet search program, which is expected to begin taking data in 2010. In preparation of this astrometric program, an infrared imaging survey has been conducted with telescopes on La Silla and Calar Alto, to identify suitable pairs of tartgets and astrometric reference stars. A list of 100 targets for the ESPRI program is being generated from this survey. In this paper, the status of the PRIMA commissioning will be summarized, the compilation of the ESPRI target list will be described, and the expected performance of the astrometric mode of the VLTI will be discussed.

Quirrenbach, Andreas; Henning, T.; Queloz, D.; ESPRI Team

2009-05-01

283

Just the Photometry: Constraining exoplanet orbits by measuring stellar densities  

Science.gov (United States)

One unique trick in toolkit of astronomers studying transiting exoplanets, is that the mean stellar density may be determined using the shape of the light curve, under various idealized assumptions such as a circular orbit and the target star is unblended. “Asterodensity profiling” seeks to exploit this trick by comparing the light curve derived stellar density to that from some independent measurement. Any difference between the two measures indicates that one or more of the idealized assumptions are invalid. Therefore, the major challenge with single-planet systems (so-called “single-body asterodensity profiling” or SAP) is distinguishing whether the difference is due to a blend, orbital eccentricity or some combination. By careful consideration of the input priors, utilizing constraints from secondary eclipses and a Bayesian analysis of the system in question, the problem is tractable though, offering the chance to determine the underlying eccentricity distribution of exoplanets and even aid in validating planet candidates through blend analysis. In this talk, I will discuss single-body asterodensity profiling (SAP) for targets with asteroseismologically determined stellar densities, which is generally considered a gold-standard measure. We have investigated several targets with the largest apparent discrepancies between the transit-derived stellar density and that from asteroseismology. By independently detrending and fitting the transit light curves, we have calculated a revised value of this crucial ratio, with various priors tried. I will present the current results our work and discuss implications for the eccentricity and blend validation of these studied systems. I will finish by exploring the exciting potential of this technique in the TESS-era, where the fact our technique requires bright-star photometry alone, opens the door to constraints for hundreds/thousands of objects.

Sliski, David; Kipping, D. M.

2014-01-01

284

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

285

Detecting industrial pollution in the atmospheres of earth-like exoplanets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

286

Ground-based detection of sodium in the transmission spectrum of exoplanet HD209458b  

Digital Repository Infrastructure Vision for European Research (DRIVER)

[Context] The first detection of an atmosphere around an extrasolar planet was presented by Charbonneau and collaborators in 2002. In the optical transmission spectrum of the transiting exoplanet HD209458b, an absorption signal from sodium was measured at a level of 0.023+-0.006%, using the STIS spectrograph on the Hubble Space Telescope. Despite several attempts, so far only upper limits to the Na D absorption have been obtained using telescopes from the ground, and the HST...

Snellen, I. A. G.; Albrecht, S.; Mooij, E. J. W.; Poole, R. S. Le

2008-01-01

287

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

288

The PANOPTES project: discovering exoplanets with low-cost digital cameras  

Science.gov (United States)

The Panoptic Astronomical Networked OPtical observatory for Transiting Exoplanets Survey (PANOPTES, www.projectpanoptes.org) project is aimed at identifying transiting exoplanets using a wide network of low-cost imaging units. Each unit consists of two commercial digital single lens reflex (DSLR) cameras equipped with 85mm F1.4 lenses, mounted on a small equatorial mount. At a few $1000s per unit, the system offers a uniquely advantageous survey eficiency for the cost, and can easily be assembled by amateur astronomers or students. Three generations of prototype units have so far been tested, and the baseline unit design, which optimizes robustness, simplicity and cost, is now ready to be duplicated. We describe the hardware and software for the PANOPTES project, focusing on key challenging aspects of the project. We show that obtaining high precision photometric measurements with commercial DSLR color cameras is possible, using a PSF-matching algorithm we developed for this project. On-sky tests show that percent-level photometric precision is achieved in 1 min with a single camera. We also discuss hardware choices aimed at optimizing system robustness while maintaining adequate cost. PANOPTES is both an outreach project and a scientifically compelling survey for transiting exoplanets. In its current phase, experienced PANOPTES members are deploying a limited number of units, acquiring the experience necessary to run the network. A much wider community will then be able to participate to the project, with schools and citizen scientists integrating their units in the network.

Guyon, Olivier; Walawender, Josh; Jovanovic, Nemanja; Butterfield, Mike; Gee, Wilfred T.; Mery, Rawad

2014-07-01

289

Clouds and Atmospheric Dynamics in Ultracool Atmospheres: HST, Spitzer, and LBT Rotational Mapping of Exoplanets and Brown Dwarfs  

Science.gov (United States)

Condensate clouds have a fundamental impact on the physical and thermal structures of photospheres of directly imaged exoplanets, brown dwarfs, and hot transiting exoplanets, but the details of cloud formation and evolution are not well understood. Rotational phase mapping of ultracool atmospheres provides exciting new insights into the physical and chemical properties of condensate clouds. Here I will summarize results from ongoing HST, Spitzer, and LBT rotational mapping projects, which provide very high quality spectrally and temporally resolved data of rotating brown dwarfs, and time-resolved photometry on directly imaged exoplanets. The multi-wavelength observations simultaneously probe clouds at multiple atmospheric depths. Finally, I will show first results from our Spitzer Cycle-9 Exploration Science program Extrasolar Storms that uses multi-epoch observations of complete rotations to study the evolution of cloud coverage in brown dwarf photospheres, thus providing detailed views of atmospheric dynamics in these ultracool atmospheres.

Apai, Daniel

2014-11-01

290

PLANETESIMAL COMPOSITIONS IN EXOPLANET SYSTEMS  

Energy Technology Data Exchange (ETDEWEB)

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, C and O abundances (and particularly the C/O abundance ratio) strongly affect the amounts of volatile ices and refractory phases in icy planetesimals formed in these systems. This results from these elements' effects on the partitioning of O among gas, refractory solid and ice phases in the final condensate. 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 mass fractions (compared to the total condensate) of refractory phases and ices were calculated for a range of nebular temperature structures 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 mass fractions of refractories, in some cases having little or no water ice. C-bearing volatile ices and clathrates also become increasingly important with increasing C/O depending on the assumed nebular temperatures. These compositional variations in early condensates in the outer portions of the nebula will be significant for the equivalent of the Kuiper Belt in these systems, icy satellites of giant planets, and the enrichment (over stellar values) of volatiles and heavy elements in giant planet atmospheres.

Johnson, Torrence V. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Mousis, Olivier [Observatoire THETA, Institut UTINAM, UMR 6213 CNRS, Universite de Franche-Comte, BP 1615, F-25010 Besancon Cedex (France); Lunine, Jonathan I. [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Madhusudhan, Nikku, E-mail: torrence.v.johnson@jpl.nasa.gov [Yale Center for Astronomy and Astrophysics, Department of Physics, Yale University, New Haven, CT 06511 (United States)

2012-10-01

291

PLANETESIMAL COMPOSITIONS IN EXOPLANET SYSTEMS  

International Nuclear Information System (INIS)

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, C and O abundances (and particularly the C/O abundance ratio) strongly affect the amounts of volatile ices and refractory phases in icy planetesimals formed in these systems. This results from these elements' effects on the partitioning of O among gas, refractory solid and ice phases in the final condensate. 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 mass fractions (compared to the total condensate) of refractory phases and ices were calculated for a range of nebular temperature structures 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 mass fractions of refractories, in some cases having little or no water ice. C-bearing volatile ices and clathrates also become increasingly important with increasing C/O depending on the assumed nebular temperatures. These compositional variations in early condensates in the outer portions of the nebula will be significant for the equivalent of the Kuipeignificant for the equivalent of the Kuiper Belt in these systems, icy satellites of giant planets, and the enrichment (over stellar values) of volatiles and heavy elements in giant planet atmospheres.

292

Massive Satellites of Close-In Gas Giant Exoplanets  

CERN Document Server

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 gravity induces significant periodic eccentricity in the satellite's orbit. The resulting tidal heating rates, per unit mass, are far in excess of Io's and dominate radioactive heating out to planet orbital periods of months for reasonable satellite tidal $Q$. Inside planet orbital periods of about a week, tidal heating can completely melt the satellite. Lastly, we compute an upper limit to the satellite mass loss rate due to thermal evaporation from the surface, valid if the satellite's atmosphere is thin and vapor pressure is negligible. ...

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

2009-01-01

293

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

International Nuclear Information System (INIS)

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

294

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

CERN Document Server

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 to be substellar: HD 68988 c with 8 M_jup 8 y. We have also searched the velocity residuals of known exoplanet systems for prospective low-amplitude exoplanets and present some candidates. We discuss techniques for constraining the mass and period of exoplanets in such cases, and for quantifying the significance of weak RV signals. We also present two substellar companions with incomplete orbits and periods longer than 8 y: HD 24040 b and HD 154345 b with M sini < 20 M_jup and M sini < 10 M_jup, respectively.

Wright, J T; Fischer, D A; Bulter, 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

295

LkCa 15: A YOUNG EXOPLANET CAUGHT AT FORMATION?  

International Nuclear Information System (INIS)

Young and directly imaged exoplanets offer critical tests of planet-formation models that are not matched by radial velocity surveys of mature stars. These targets have been extremely elusive to date, with no exoplanets younger than 10-20 Myr and only a handful of direct-imaged exoplanets at all ages. We report the direct-imaging discovery of a likely (proto)planet around the young (?2 Myr) solar analog LkCa 15, located inside a known gap in the protoplanetary disk (a 'transitional disk'). Our observations use non-redundant aperture masking interferometry at three epochs to reveal a faint and relatively blue point source (MK'=9.1±0.2, K' – L' = 0.98 ± 0.22), flanked by approximately co-orbital emission that is red and resolved into at least two sources (ML'=7.5±0.2, K' – L' = 2.7 ± 0.3; ML'=7.4±0.2, K' – L' = 1.94 ± 0.16). We propose that the most likely geometry consists of a newly formed (proto)planet that is surrounded by dusty material. The nominal estimated mass is ?6 MJup according to the 1 Myr hot-start models. However, we argue based on its luminosity, color, and the presence of circumplanetary material that the planet has likely been caught at its epoch of assembly, and hence this mass is an upper limit due to its extreme youth and flux contributed by accretion. The projected separations (71.9 ± 1.6 mas, 100.7 ± 1.9 mas, and 88.2 ± 1.8 mas) and deprojected orbital radii (16, 21, and 19 AU) correspond to the center of the disk gap, but are too close to the primary star for a circular orbit to account for the observed inner edge of the outer disk, so an alternative explanation (i.e., additional planets or an eccentric orbit) is likely required. This discovery is the first direct evidence that at least some transitional disks do indeed host newly formed (or forming) exoplanetary systems, and the observed properties provide crucial insight into the gas giant formation process.

296

Identifying new opportunities for exoplanet characterisation at high spectral resolution  

Science.gov (United States)

Context. Recently, there have been a series of detections of molecules in the atmospheres of extrasolar planets using high spectral resolution (R ~ 100 000) observations, mostly using the CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) on the Very Large Telescope. These measurements are able to resolve molecular bands into individual absorption lines. Observing many lines simultaneously as their Doppler shift changes with time allows the detection of specific molecules in the atmosphere of the exoplanet. Aims: We aim to identify new ways of increasing the planet signal in these kinds of high-resolution observations. First of all, we wish to determine what wavelength settings can best be used to target certain molecules. Furthermore, we want to simulate exoplanet spectra of the day-side and night-side to see whether night-side observations are feasible at high spectral resolution. Methods: We performed simulations of high-resolution CRIRES observations of a planet's thermal emission and transit between 1 and 5 ?m and performed a cross-correlation analysis on these results to assess how well the planet signal can be extracted. These simulations take into account telluric absorption, sky emission, realistic noise levels, and planet-to-star contrasts. We also simulated day-side and night-side spectra at high spectral resolution for planets with and without a day-side temperature inversion, based on the cases of HD 189733b and HD 209458b. Results: Several small wavelength regions in the L-band promise to yield cross-correlation signals from the thermal emission of hot Jupiters of H2O, CH4, CO2, C2H2, and HCN that can exceed those of the current detections by up to a factor of 2-3 for the same integration time. For transit observations, the H-band is also attractive, with the H, K, and L-bands giving cross-correlation signals of similar strength. High-resolution night-side spectra of hot Jupiters can give cross-correlation signals as high as the day-side, or even higher. Conclusions: We show that there are many new possibilities for high-resolution observations of exoplanet atmospheres that have expected planet signals at least as high as those already detected. Hence, high-resolution observations at well-chosen wavelengths and at different phases can improve our knowledge about hot Jupiter atmospheres significantly, already with currently available instrumentation.

de Kok, R. J.; Birkby, J.; Brogi, M.; Schwarz, H.; Albrecht, S.; de Mooij, E. J. W.; Snellen, I. A. G.

2014-01-01

297

Detection and Exploration of Planets from the Trans-atlantic Exoplanet Survey  

Science.gov (United States)

The Trans-atlantic Exoplanet Survey (TrES) is a network of three small-aperture telescopes dedicated to searching the skies for new transiting extrasolar gas giants. The TrES team have discovered two of the 14 known transiting exoplanets. We discuss the detection and exploration of these nearby planets and present the latest observations of TrES-2. TrES-2 is the most massive of the nearby transiting planets, and the first transiting planet found within the field of view of the NASA Kepler transit-search mission. TrES was motivated by our incomplete understanding of the structure and composition of highly-insolated gas giants, and is one of several wide-field photometric campaigns to find new transiting planets. Astrophysical false positives, such as grazing eclipsing binaries, are the dominant source of transit-like periodic signals from these campaigns. Hence follow-up observations are required for all planet candidates. In particular, recent experience has highlighted the need for careful analysis to eliminate astronomical systems where light from a faint eclipsing binary is blended with that from a bright star. We present here examples of the procedure followed by the TrES network to identify false positive candidates. This material is based upon work supported by the National Aeronautics and Space Administration under grant NNG05GJ29G, issued through the Origins of Solar Systems Program.

O'Donovan, Francis T.; Charbonneau, D.; Hillenbrand, L.

2006-12-01

298

Deformable Mirrors Capture Exoplanet Data, Reflect Lasers  

Science.gov (United States)

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

2014-01-01

299

LEECH: LBTI Exozodi Exoplanet Common Hunt  

Science.gov (United States)

In Spring 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began its 100-night campaign from the Large Binocular Telescope (LBT) atop Mt Graham, Arizona. This survey benefits from the many technological achievements of the LBT, including two 8.4- meter mirrors on a single fixed mount, dual adaptive secondary mirrors for high Strehl performance, and a cold beam combiner to dramatically reducing the telescope's overall background emissivity. LEECH neatly complements other high-contrast planet imaging efforts by observing stars at L' (3.8 microns) with LMIRcam, as opposed to the shorter wavelength near-infrared bands (1-2.4 microns) of other similar surveys. This portion of the spectrum offers deeper mass sensitivity for intermediate age (several hundred Myr-old) systems, since their Jovian-mass planets radiate predominantly in the mid-infrared. The goals of LEECH are to (1) discover new exoplanets, (2) characterize the atmospheres of newly discovered exoplanets, (3) characterize the architectures of nearby planetary systems, and (4) establish meaningful constraints on the prevalence of wideseparation exoplanets.

Skemer, A.

2014-03-01

300

The Transit Monitoring in the South (TraMoS project  

Directory of Open Access Journals (Sweden)

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

López-Morales Mercedes

2013-04-01

 
 
 
 
301

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

CERN Document Server

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

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

2013-01-01

302

Miniature Exoplanet Radial Velocity Array (MINERVA) I. Design, Commissioning, and First Science Results  

CERN Document Server

The MINiature Exoplanet Radial Velocity Array (MINERVA) is a US-based observational facility dedicated to the discovery and characterization of exoplanets around a nearby sample of bright stars. MINERVA employs a robotic array of four 0.7 m telescopes outfitted for both high-resolution spectroscopy and photometry, and is designed for completely autonomous operation. The primary science program is a dedicated radial velocity survey and the secondary science objective is to obtain high precision transit light curves. The modular design of the facility and the flexibility of our hardware allows for both science programs to be pursued simultaneously, while the robotic control software provides a robust and efficient means to carry out nightly observations. In this article, we describe the design of MINERVA including major hardware components, software, and science goals. The telescopes and photometry cameras are characterized at our test facility on the Caltech campus in Pasadena, CA, and their on-sky performance...

Swift, Jonathan J; Johnson, John A; Wright, Jason T; McCrady, Nate; Wittenmyer, Robert A; Plavchan, Peter; Riddle, Reed; Muirhead, Philip S; Herzig, Erich; Myles, Justin; Blake, Cullen H; Eastman, Jason; Beatty, Thomas G; Lin, Brian; Zhao, Ming; Gardner, Paul; Falco, Emilio; Criswell, Stephen; Nava, Chantanelle; Robinson, Connor; Sliski, David H; Hedrick, Richard; Ivarsen, Kevin; Hjelstrom, Annie; de Vera, Jon; Szentgyorgyi, Andrew

2014-01-01

303

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

CERN Document Server

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

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

2008-01-01

304

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

CERN Document Server

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

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

2014-01-01

305

A TEMPERATURE AND ABUNDANCE RETRIEVAL METHOD FOR EXOPLANET ATMOSPHERES  

International Nuclear Information System (INIS)

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

306

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

Directory of Open Access Journals (Sweden)

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

Venot Olivia

2014-02-01

307

Characterizing the Coolest Atmospheres: Exoplanets to Brown Dwarfs  

Science.gov (United States)

We present the results of two complementary programs characterizing planetary temperature sub-stellar targets. The first project is a near-infrared surveys monitoring 74 L, T and Y brown dwarfs for variability. With the discovery of Y dwarfs by the WISE mission, the population of field brown dwarfs now extends to objects with temperatures comparable to those of Solar System planets. To investigate the atmospheres of these ultracool brown dwarfs with temperatures covering the range of transiting and directly imaged planets, we conducted a large near-infrared photometric monitoring campaign in the J-band using both the SOFI camera on the 3.5 NTT and the SWIRC camera on the 6.5-m MMT. Breakup of the iron and silicate clouds into a patchy cloud layer has been suggested as an explanation of several large variables identified at the L/T transition, and a similar process with sulfide and salt clouds may be manifest in T/Y transition objects. We detected a total of 16 variable targets in the sample with 11 of these being new previously unknown variables. The second project is designed to characterize the planetary system HR8799 in the near infrared water bands obscured by the Earths atmosphere with the Hubble Space Telescope. These dataset will provide invaluable in the generation of new atmospheric models of brown dwarfs and directly detected exoplanets.

Rajan, A.; Patience, J.; Barman, T.; Soummer, R.; Wilson, P. A.; Pueyo, L.; Pont, F.; Rosa, R. J. D.; Morley, C. V.; Fortney, J. J.; Marois, C.; Macintosh, B.

2014-03-01

308

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

CERN Document Server

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

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

2013-01-01

309

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

Science.gov (United States)

Transit observations of the hydrogen Lyman-? line allowed the detection of atmospheric escape from the exoplanet HD209458b (Vidal-Madjar et al. 2003). Using spectrally resolved Lyman-? transit observations of the exoplanet HD 189733b at two different epochs, Lecavelier des Etangs et al. (2012) detected for the first time temporal variations in the physical conditions of an evaporating planetary atmosphere. Here we summarized the results obtained with the HST/STIS observations as presented in June 2012 at the SF2A 2012 meeting. While atmospheric hydrogen cannot be detected in the STIS observations of April 2010, it is clearly detected in the September 2011 observations. The atomic hydrogen cloud surrounding the transiting planet produces a transit absorption depth of 14.4±3.6% between velocities of -230 to -140 km s^{-1}. These high velocities cannot arise from radiation pressure alone and, contrary to HD 209458b, this requires an additional acceleration mechanism, such as interactions with stellar wind protons. The spectral and temporal signature of the absorption is fitted by an atmospheric escape rate of neutral hydrogen atoms of about 10^9 g s^{-1}, a stellar wind with a velocity of 190 km s^{-1} and a temperature of ˜10^5 K. We also illustrate the power of multi-wavelengths approach with simultaneous observations in the X-rays obtained with Swift/XRT. We detected an X-ray flare about 8 hours before the transit of September 2011. This suggests that the observed changes within the upper part of the escaping atmosphere can be caused by variations in the stellar wind properties, or/and by variations in the stellar energy input to the planet's escaping gas. This multi-wavelengths approach allowed the simultaneous detection of temporal variations both in the stellar X-ray and in the planetary upper atmosphere, providing first observational constraints on the interaction between the exoplanet's atmosphere and the star.

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

2012-12-01

310

Instrumentation for the detection and characterization of exoplanets  

Science.gov (United States)

In no other field of astrophysics has the impact of new instrumentation been as substantial as in the domain of exoplanets. Before 1995 our knowledge of exoplanets was mainly based on philosophical and theoretical considerations. The years that followed have been marked, instead, by surprising discoveries made possible by high-precision instruments. Over the past decade, the availability of new techniques has moved the focus of research from the detection to the characterization of exoplanets. Next-generation facilities will produce even more complementary data that will lead to a comprehensive view of exoplanet characteristics and, by comparison with theoretical models, to a better understanding of planet formation.

Pepe, Francesco; Ehrenreich, David; Meyer, Michael R.

2014-09-01

311

Thermal architecture of the Exoplanet Characterisation Observatory payload  

Science.gov (United States)

The Exoplanet Characterisation Observatory (EChO) is a space project currently under study by ESA in the context of a medium class mission within the Cosmic Vision programme for launch post 2020. The EChO main scientific objectives are based on spectroscopy of transiting exoplanets over a wide range of wavelengths, from visible to mid-infrared. The high sensitivity requirements of the mission need an extremely stable thermo-mechanical platform. In this paper we describe the thermal architecture of the payload and discuss the main requirements that drive the design. The instrument is passively cooled to a temperature close to 45K, together with the telescope, to achieve the required sensitivity and photometric stability. Passive cooling is achieved by a V-Groove based design that exploits the L2 orbit favorable thermal conditions. The Visible and short-IR wavelength detectors are maintained at the operating temperature of 40K by a dedicated radiator coupled to cold space. The mid-IR channels require lower temperature references for both the detectors and part of the optical units. These colder stages are provided by an active cooling system based on a Neon Joule-Thomson cold end, fed by a mechanical compressor, able to reach temperatures active solutions needed to maintain the required stability at the detector stages level is described. We report here about the baseline thermal architecture at the end of the Study Phase, together with the main trade-offs needed to enable the EChO exciting science in a technically feasible payload design. Thermal modeling results and preliminary performance predictions in terms of steady state and transient behavior are also discussed. This paper is presented on behalf of the EChO Consortium.

Morgante, G.; Terenzi, L.; Eccleston, P.; Bradshaw, T.; Crook, M.; Focardi, M.; Hunt, T.; Winter, B.; Malaguti, G.; Micela, G.; Pace, E.; Tinetti, G.

2014-08-01

312

Understanding Young Exoplanet Analogs with WISE  

Science.gov (United States)

We propose to tackle outstanding questions about the fundamental properties of young brown dwarfs, which are atmospheric analogs to massive gas giant exoplanets, using public archive data from the Wide-field Infrared Survey Explorer (WISE) combined with our extensive dataset of optical and near-infrared observations, including spectra, proper motions, and parallaxes. Using WISE data we will construct color-color diagrams, color- magnitude diagrams, and spectral energy distributions for our sample of candidate young brown dwarfs. We will fully characterize the spectral properties of the candidates and evaluate their membership in nearby young moving groups in order to obtain independent age estimates. The practical outcomes of this project will allow the research community to use observed colors and spectra to reliably constrain the properties - including effective temperature, gravity, and dust/cloud properties - of both brown dwarfs and gas giant exoplanets. We will also search for new young brown dwarfs in the WISE archive using colors and proper motions. The expanded sample of young brown dwarfs will be used to create a self-contained feedback loop to identify and address the shortcomings of cool atmosphere models and low-mass evolutionary tracks, both of which are already being used to infer the properties of massive exoplanets. Disentangling the effects of physical parameters on the observed properties of young brown dwarfs is directly relevant to studies of exoplanets. Direct observations of exoplanets are currently very limited, and young brown dwarfs are the laboratories in which we can solve existing problems before the onslaught of new observations from instruments capable of directly imaging exoplanets, including the Gemini Planet Imager, Project 1640 at the Palomar Observatory, SPHERE on the VLT, and the James Webb Space Telescope. This project addresses the goal of the NASA Science Mission Directorate to discover how the universe works; in particular, the results of our work will improve our understanding of objects at the intersection of stars and planets and be directly applicable to understanding the atmospheres of directly-imaged exoplanets. The assembled investigators are the absolute best team to accomplish this work. They have extensive and diverse observational experience in astrometry, photometry, and spectroscopy from the optical through the mid-IR, spanning nearly the entire spectral energy distribution of young brown dwarfs and encompassing their most fundamental observational properties. They have considerable experience mining large photometric catalogs and identifying low-gravity very low mass objects. The team maintains collaborations with two groups actively modelling brown dwarf and exoplanet atmospheres and interior evolution. The proposed research organically combines several ongoing projects into a cohesive program that will efficiently incorporate WISE data to disentangle the ambiguous and interdependent physical properties of young brown dwarfs. As a result of the team's previous observational projects, we have assembled a dataset that positions us to best interpret WISE observations brown dwarfs and identify new young brown dwarfs in the WISE archive. A significant parallax program is ongoing, and all of the computing resources and many of the analysis tools are already in place, including several well-tested pipelines for data reduction and analysis and model comparisons. The team will incorporate undergraduate students in the project through an existing NSF-funded REU program.

Rice, Emily

313

Characterizing the Parents: Exoplanets Around Cool Stars  

CERN Document Server

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 volume with which to calibrate the methods. We show results from our CHARA survey that provides directly determined stellar parameters based on interferometric diameter measurements, trigonometric parallax, and spectral energy distribution fitting.

von Braun, Kaspar; van Belle, Gerard T; Mann, Andrew; Kane, Stephen R

2014-01-01

314

Exoplanet Characterization and the Search for Life  

CERN Document Server

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

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

2009-01-01

315

Transiting exoplanets from the CoRoT space mission : XXII. CoRoT-16b: a hot Jupiter with a hint of eccentricity around a faint solar-like star  

DEFF Research Database (Denmark)

Aims. We report the discovery of CoRoT-16b, a low density hot jupiter that orbits a faint G5V star (mV = 15.63) in 5.3523 ± 0.0002 days with slight eccentricity. A fit of the data with no a priori assumptions on the orbit leads to an eccentricity of 0.33 ± 0.1. We discuss this value and also derive the mass and radius of the planet. Methods. We analyse the photometric transit curve of CoRoT-16 given by the CoRoT satellite, and radial velocity data from the HARPS and HIRES spectrometers. A combined analysis using a Markov chain Monte Carlo algorithm is used to get the system parameters. Results. CoRoT-16b is a 0.535 ?0.083/+0.085 MJ, 1.17 ?0.14/+0.16 RJ hot Jupiter with a density of 0.44 ?0.14/+0.21 g?cm-3. Despite its short orbital distance (0.0618 ± 0.0015 AU) and the age of the parent star (6.73 ± 2.8 Gyr), the planet orbit exhibits significantly non-zero eccentricity. This is very uncommon for this type of objects as tidal effects tend to circularise the orbit. This value is discussed taking into account the characteristics of the star and the observation accuracy.

Ollivier, M.; Gillon, M.

2012-01-01

316

The far future of exoplanet direct characterization  

CERN Document Server

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

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

2009-01-01

317

Advances in exoplanet science from Kepler  

CERN Document Server

Numerous telescopes and techniques have been used to find and study extrasolar planets, but none has been more successful than NASA's Kepler Space Telescope. Kepler has discovered the majority of known exoplanets, the smallest planets to orbit normal stars, and the worlds most likely to be similar to our home planet. Most importantly, Kepler has provided our first look at typical characteristics of planets and planetary systems for planets with sizes as small as and orbits as large as those of the Earth.

Lissauer, Jack J; Tremaine, Scott

2014-01-01

318

THEORETICAL SPECTRA OF TERRESTRIAL EXOPLANET SURFACES  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-06-10

319

THEORETICAL SPECTRA OF TERRESTRIAL EXOPLANET SURFACES  

International Nuclear Information System (INIS)

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

320

Mass-Radius Relationships for Solid Exoplanets  

CERN Document Server

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

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

2007-01-01

 
 
 
 
321

Mass-radius relationships for exoplanets  

CERN Document Server

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

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

2010-01-01

322

The NASA/IPAC/NExScI Star and Exoplanet Database  

CERN Document Server

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

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

2009-01-01

323

Photometric stability analysis of 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, the Exoplanet Characterisation Observatory (EChO) has been considered as medium- sized M3 mission candidate for launch in the 2022 - 2024 timeframe [3]. The current 'Phase-A study' space-mission concept is a 1.2 metre class telescope, passively cooled to ?50 K and orbiting around the second Lagrangian Point (L2). The current baseline for the payload consists of four integrated spectrographs providing continuous spectral coverage from 0.5 - 16?m at resolution ranging from R ? 300 to 30.

Waldmann, I. P.; Pascale, E.; Tessenyi, M.; Spencer, L.; Amaral-Rogers, A.; Ollivier, M.; Coudé du Foresto, V.

2013-09-01

324

Circulation Models of Close-In Exoplanet Atmospheres  

Science.gov (United States)

Many exoplanets, including those best suited for characterization, are on close-in orbits and are likely tidally synchronized. Atmospheric circulation affects the temperature distribution and thus transit observations of these planets. In particular, hot spots shifted by broad, steady, superrotating jets have been emphasized in the literature. We present results from a general circulation model, solving the primitive equations with thermal relaxation. The mini-Neptune GJ1214b and hot Jupiter HD209458b are used as reference planets. We explore a variety of conditions for forcing and initialization which lead to different states. The resulting states have in common a low number of jets, but large-scale vortices also play a big role and often exhibit time variability (with corresponding variability in the position of relative hot and cold regions). In contrast to many studies, we find and explore cases where the equatorial jet can be westward as well as eastward (superrotating) for tidally locked forcing conditions. For a given forcing, varying initial conditions leads to different states, but a given run also exhibits transitions between distinguishable long-lasting (hundreds or thousands of planet rotations) states during its long term evolution.

Thrastarson, H. Th.; Cho, J. Y.-K.; Chen, P.

2013-09-01

325

Electron densities and alkali atoms in exoplanet atmospheres  

Science.gov (United States)

We describe a detailed study on the properties of alkali atoms in extrasolar giant planets, and specifically focus on their role in generating the atmospheric free electron densities, as well as their impact on the transit depth observations. We focus our study on the case of HD 209458 b, and we show that photoionization produces a large electron density in the middle atmosphere that is about two orders of magnitude larger than the density anticipated from thermal ionization. Our purely photochemical calculations though result in a much larger transit depth for K than observed for this planet. This result does not change even if the roles of molecular chemistry and excited state chemistry are considered for the alkali atoms. In contrast, the model results for the case of exoplanet XO-2 b are in good agreement with the available observations. Given these results we discuss other possible scenarios, such as changes in the elemental abundances, changes in the temperature profiles, and the possible presence of clouds, which could potentially explain the observed HD 209458 b alkali properties. We find that most of these scenarios can not explain the observations, with the exception of a heterogeneous source (i.e. clouds or aerosols) under specific conditions, but we also note the discrepancies among the available observations.

Lavvas, Panayotis; Koskinen, Tommi; Yelle, Roger

2014-11-01

326

Electron densities and alkali atoms in exoplanet atmospheres  

CERN Document Server

We describe a detailed study on the properties of alkali atoms in extrasolar giant planets, and specifically focus on their role in generating the atmospheric free electron densities, as well as their impact on the transit depth observations. We focus our study on the case of HD 209458 b, and we show that photoionization produces a large electron density in the middle atmosphere that is about two orders of magnitude larger than the density anticipated from thermal ionization. Our purely photochemical calculations though result in a much larger transit depth for K than observed for this planet. This result does not change even if the roles of molecular chemistry and excited state chemistry are considered for the alkali atoms. In contrast, the model results for the case of exoplanet XO-2 b are in good agreement with the available observations. Given these results we discuss other possible scenarios, such as changes in the elemental abundances, changes in the temperature profiles, and the possible presence of cl...

Lavvas, Panayotis; Yelle, Roger V

2014-01-01

327

Fractal analysis of noise buried time series signals with applications to exoplanet spectroscopy and bio-data  

Science.gov (United States)

The shape of an exoplanet lightcurve is usually obtained by averaging the noise over multiple datasets. Fractal analysis has been demonstrated to be an effective tool for the detection of exoplanet transits using lightcurves summed over all wavelengths sensitive to the detector (G. Tremberger, Jr et. al, 2006 Proc SPIE Vol 6265). The detection of spectral features would depend on the extent to which the signal was buried in the noise. Different noise sources would have different fractal characteristics. Also, the signal strength could be discontinuous in time depending on the exoplanet's local atmospheric environment. Such a discontinuity is unlikely to be detected with time integrated data. The lightcurve noise and shape information were characterized with fractal dimension analysis of a noise buried time series signal. Computer simulation revealed that when the noise is three times that of the signal, the fractal algorithm could detect the signal at about the 87% confidence level. Application to noise buried time series datasets (HD 209458b lightcurve, HD149026b lightcurve) detected discontinuities consistent with the results obtained by averaging datasets. Extension to individual wavelength lightcurves would establish a detection limit for the existence of spectral features at wavelengths important for exoplanet study. Other applications such as pre-implantation genetic screening spectroscopy and spatially varied aneuploidy bio-data could use the same analysis principle as well.

Tremberger, George, Jr.; Holden, T.; Cheung, E.; Flamholz, A.; Marchese, P.; Yao, H.; Schneider, P.; Lieberman, D. H.; Cheung, T. D.

2007-09-01

328

Search for a circum-planetary material and orbital period variations of short-period Kepler exoplanet candidates  

CERN Document Server

A unique short-period Mercury-size Kepler exoplanet candidate KIC012557548b has been discovered recently by Rappaport et al. (2012). This object is a transiting disintegrating exoplanet with a circum-planetary material - comet-like tail. Close-in exoplanets, like KIC012557548b, are subjected to the greatest planet-star interactions. This interaction may have various forms. In certain cases it may cause formation of the comet-like tail. Strong interaction with the host star, and/or presence of an additional planet may lead to variations in the orbital period of the planet. Our main aim is to search for comet-like tails similar to KIC012557548b and for long-term orbital period variations. We are curious about frequency of comet-like tail formation among short-period Kepler exoplanet candidates. We concentrate on a sample of 20 close-in candidates with a period similar to KIC012557548b from the Kepler mission.

Garai, Z; Budaj, J; Stellingwerf, R F

2014-01-01

329

Exoplanet atmospheres with EChO: spectral retrievals using EChOSim  

CERN Document Server

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

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

2014-01-01

330

THE ULTRAVIOLET RADIATION ENVIRONMENT AROUND M DWARF EXOPLANET HOST STARS  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-02-15

331

The Ultraviolet Radiation Environment around M Dwarf Exoplanet Host Stars  

Science.gov (United States)

The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. Ultraviolet photons influence the atmospheric temperature profiles and production of potential biomarkers on Earth-like planets around these stars. At present, little observational or theoretical basis exists for understanding the ultraviolet spectra of M dwarfs, despite their critical importance to predicting and interpreting the spectra of potentially habitable planets as they are obtained in the coming decades. Using observations from the Hubble Space Telescope, we present a study of the UV radiation fields around nearby M dwarf planet hosts that covers both far-UV (FUV) and near-UV (NUV) wavelengths. The combined FUV+NUV spectra are publicly available in machine-readable format. We find that all six exoplanet host stars in our sample (GJ 581, GJ 876, GJ 436, GJ 832, GJ 667C, and GJ 1214) exhibit some level of chromospheric and transition region UV emission. No "UV-quiet" M dwarfs are observed. The bright stellar Lyman-alpha emission lines are reconstructed, and we find that the Lyman-alpha line fluxes comprise approximately 37%-75% of the total 1150-3100 A flux from most M dwarfs; approximately greater than 10(exp3) times the solar value. We develop an empirical scaling relation between Lyman-alpha and Mg II emission, to be used when interstellar H I attenuation precludes the direct observation of Lyman-alpha. The intrinsic unreddened flux ratio is F(Lyman-alpha)/F(Mg II) = 10(exp3). The F(FUV)/F(NUV) flux ratio, a driver for abiotic production of the suggested biomarkers O2 and O3, is shown to be approximately 0.5-3 for all M dwarfs in our sample, greather than 10(exp3) times the solar ratio. For the four stars with moderate signal-to-noise Cosmic Origins Spectrograph time-resolved spectra, we find UV emission line variability with amplitudes of 50%.500% on 10(exp2)-10(exp3) s timescales. This effect should be taken into account in future UV transiting planet studies, including searches for O3 on Earth-like planets. Finally, we observe relatively bright H2 fluorescent emission from four of the M dwarf exoplanetary systems (GJ 581, GJ 876, GJ 436, and GJ 832). Additional modeling work is needed to differentiate between a stellar photospheric or possible exoplanetary origin for the hot (T(H2) approximately equal to 2000-4000 K) molecular gas observed in these objects.

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

2013-01-01

332

Towards Polarimetric Exoplanet Imaging with ELTs  

Science.gov (United States)

A prime science goal of Extremely Large Telescopes (ELTs) is the detection and characterization of exoplanets to answer the question: are we alone? ELTs will obtain the first direct images of rocky exoplanets in the habitable zone and search for atmospheric biomarkers. However, the required instrumental technologies are not yet at a level where an instrument could be built that would achieve this goal. Polarimetry will be an important ingredient in future high-contrast instruments as it will provide a major contrast improvement for planets located within the first two Airy rings and offers unique diagnostic capabilities for liquid water (ocean glint, water clouds and their rainbows), hazes and dust in exoplanetary atmospheres. We will describe novel instrumental approaches to improving subsystems, in particular polarimetry, wavefront sensing and adaptive optics control. To reach contrasts of 10-9 and beyond to image rocky exoplanets from the ground, a series of individually optimized subsystems cannot succeed; rather, entire combinations of subsystems must be optimized together. We will describe our efforts at measuring and controlling wavefronts with 40'000 degrees of freedom, reaching the photon-noise limit in high-contrast polarimetric imaging at telescopes and our plans to reach a contrast of at least 10-9 in broadband light under realistic, simulated ground-based conditions in the laboratory and to test new approaches at telescopes, in particular achromatic aperture and focal-plane coronagraphs, focal-plane wavefront-sensing and speckle suppression, integral-field polarimetry and high-contrast data reduction algorithms.

Keller, C. U.; Korkiakoski, V.; Rodenhuis, M.; Snik, F.

2014-03-01

333

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-09-20

334

Cyclic Transit Probabilities of Long-Period Eccentric Planets Due to Periastron Precession  

CERN Document Server

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

Kane, Stephen R; von Braun, Kaspar

2012-01-01

335

Terrestrial exoplanets: diversity, habitability and characterization  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-08-15

336

Young Brown Dwarfs as Giant Exoplanet Analogs  

CERN Document Server

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

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

2013-01-01

337

Brown Dwarfs at the Exoplanet Mass Boundary  

Science.gov (United States)

Young brown dwarfs and directly-imaged exoplanets have enticingly similar photometric and spectroscopic characteristics, indicating that their cool, low gravity atmospheres should be studied in concert. Similarities between the peculiar shaped H band, near and mid-IR photometry as well as location on color magnitude diagrams provide important clues about how to extract physical properties of planets from current brown dwarf observations. Our team has assigned >30 brown dwarfs to 10-150 Myr nearby moving groups. In so doing, we have discovered important diversity among this extremely low-mass (10 - 30 M_{Jup}) age-calibrated sample indicating that cloud properties play a critical role in their observables.

Faherty, J. K.; Cruz, K. L.; Rice, E. L.; Riedel, A.

2014-10-01

338

Exoplanets Bouncing Between Binary Stars  

CERN Document Server

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

Moeckel, Nickolas

2012-01-01

339

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

CERN Document Server

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

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

2012-01-01

340

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

International Nuclear Information System (INIS)

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

 
 
 
 
341

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-03-15

342

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

CERN Document Server

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

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

2012-01-01

343

Algol: An Early Candidate for a Transiting Exoplanet  

Science.gov (United States)

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

French, Linda M.; Stuart, I.

2008-09-01

344

Exoplanet Atmospheres in High Definition: 3D Eclipse Mapping of HD 209458b and HD 189733b  

Science.gov (United States)

Eclipse mapping is a newly developed technique in the arsenal of observational methods aimed at the characterization of exoplanet atmospheres. This technique was first applied to HD189733b using multiple 8 micron secondary eclipse observations to create a high-resolution snapshot of the dayside of the planet. The eclipse map of HD189733b at 8 microns was able to resolve the dayside brightness distribution of the planet both in latitude and longitude giving key insights into the atmospheric circulation of HD189733b. Here we propose to use this eclipse mapping technique to produce dayside brightness maps of the benchmark exoplanets HD189733b and HD209458b at both 3.6 and 4.5 microns. By combining brightness maps at multiple wavelengths, we will create the first three-dimensional maps of an exoplanet atmosphere (latitude, longitude, and pressure). HD209458 and HD189733 are among the brightest (Ks~6) planet harboring system and represent our best opportunity to achieve a high signal-to-noise eclipse maps. Comparisons between the brightness maps of these two planets will highlight key differences in the atmospheric circulation patterns of planets with (HD209458b) and without (HD189733b) thermal inversions in their dayside atmospheres. The atmospheres of HD189733b and HD209458b have been previously probed at wavelengths from the infrared to the ultraviolet through transit, eclipse, and phase-curve observations. With the addition of the three-dimensional eclipse maps proposed here, we will answer many of the outstanding questions about the basic radiative, chemical, and advective processes at work in these key planetary atmospheres. The observations proposed here will allow us to make the first direct comparisons of the observed thermal structure of an exoplanet with the plethora of three-dimensional atmospheric circulation models developed specifically for HD189733b and HD209458b, thus both informing the models and gaining new insights into the complex circulation patterns of exoplanet atmospheres.

Lewis, Nikole; Cowan, Nicolas; Knutson, Heather; de Wit, Julien; Seager, Sara; Demory, Brice-Olivier; Fortney, Jonathan; Showman, Adam

2013-10-01

345

Abundance Stratification of Exoplanet Host Stars  

CERN Document Server

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

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

2008-01-01

346

Exoplanet Searches by Future Deep Space Missions  

Directory of Open Access Journals (Sweden)

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

Maccone C.

2011-02-01

347

PynPoint Code for Exoplanet Imaging  

CERN Document Server

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

Amara, Adam; Akeret, Joel

2014-01-01

348

Exoplanets finding, exploring, and understanding alien worlds  

CERN Document Server

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

Kitchin, Chris

2012-01-01

349

ESPRESSO: The next European exoplanet hunter  

Science.gov (United States)

The acronym ESPRESSO stems for Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations; this instrument will be the next VLT high resolution spectrograph. The spectrograph will be installed at the Combined-Coudé Laboratory of the VLT and linked to the four 8.2 m Unit Telescopes (UT) through four optical Coudé trains. ESPRESSO will combine efficiency and extreme spectroscopic precision. ESPRESSO is foreseen to achieve a gain of two magnitudes with respect to its predecessor HARPS, and to improve the instrumental radial-velocity precision to reach the 10 cm s-1 level. It can be operated either with a single UT or with up to four UTs, enabling an additional gain in the latter mode. The incoherent combination of four telescopes and the extreme precision requirements called for many innovative design solutions while ensuring the technical heritage of the successful HARPS experience. ESPRESSO will allow to explore new frontiers in most domains of astrophysics that require precision and sensitivity. The main scientific drivers are the search and characterization of rocky exoplanets in the habitable zone of quiet, nearby G to M-dwarfs and the analysis of the variability of fundamental physical constants. The project passed the final design review in May 2013 and entered the manufacturing phase. ESPRESSO will be installed at the Paranal Observatory in 2016 and its operation is planned to start by the end of the same year.

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

2014-01-01

350

MODELS OF NEPTUNE-MASS EXOPLANETS: EMERGENT FLUXES AND ALBEDOS  

International Nuclear Information System (INIS)

There are now many known exoplanets with Msin i within a factor of 2 of Neptune's, including the transiting planets GJ 436b and HAT-P-11b. Planets in this mass range are different from their more massive cousins in several ways that are relevant to their radiative properties and thermal structures. By analogy with Neptune and Uranus, they are likely to have metal abundances that are an order of magnitude or more greater than those of larger, more massive planets. This increases their opacity, decreases Rayleigh scattering, and changes their equation of state. Furthermore, their smaller radii mean that fluxes from these planets are roughly an order of magnitude lower than those of otherwise identical gas giant planets. Here, we compute a range of plausible radiative equilibrium models of GJ 436b and HAT-P-11b. In addition, we explore the dependence of generic Neptune-mass planets on a range of physical properties, including their distance from their host stars, their metallicity, the spectral type of their stars, the redistribution of heat in their atmospheres, and the possible presence of additional optical opacity in their upper atmospheres.

351

MASSIVE SATELLITES OF CLOSE-IN GAS GIANT EXOPLANETS  

International Nuclear Information System (INIS)

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

352

VAPORIZATION OF THE EARTH: APPLICATION TO EXOPLANET ATMOSPHERES  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-08-10

353

VAPORIZATION OF THE EARTH: APPLICATION TO EXOPLANET ATMOSPHERES  

International Nuclear Information System (INIS)

Currently, there are about three dozen known super-Earths (M ?), of which eight are transiting planets suitable for atmospheric follow-up observations. Some of the planets are exposed to extreme temperatures as they orbit close to their host stars, e.g., CoRot-7b, and all of these planets have equilibrium temperatures significantly hotter than the Earth. Such planets can develop atmospheres through (partial) vaporization of their crustal and/or mantle silicates. We investigated the chemical equilibrium composition of such heated systems from 500 to 4000 K and total pressures from 10–6 to 10+2 bars. The major gases are H2O and CO2 over broad temperature and pressure ranges, and Na, K, O2, SiO, and O at high temperatures and low pressures. We discuss the differences in atmospheric composition arising from vaporization of SiO2-rich (i.e., felsic) silicates (like Earth's continental crust) and MgO-, FeO-rich (i.e., mafic) silicates (like the bulk silicate Earth). The computational results will be useful in planning spectroscopic studies of the atmospheres of Earth-like exoplanets.

354

Atmospheric circulation and climate of terrestrial exoplanets and super Earths  

Science.gov (United States)

The recent discovery of super Earths and terrestrial exoplanets extending over a broad region of orbital and physical parameter space suggests that these planets will span a wide range of climatic regimes. Characterization of the atmospheres of warm super Earths has already begun and will be extended to smaller and more distant planets over the coming decade. The habitability of these worlds may be strongly affected by their three-dimensional atmospheric circulation regimes, since the global climate feedbacks that control the inner and outer edges of the habitable zone--including transitions to Snowball-like states and runaway-greenhouse feedbacks--depend on the equator-to-pole temperature differences, pattern of relative humidity, and other aspects of the dynamics. Here, using an idealized moist atmospheric general circulation model (GCM) including a hydrological cycle, we study the dynamical principles governing the atmospheric dynamics on such planets. In this presentation we will review how the planetary rotation rate, planetary mass, heat flux from a parent star and atmospheric mass affect the atmospheric circulation and temperature distribution on such planets. We will elucidate the possible climatic regimes and diagnose the mechanisms controlling the formation of atmospheric jet streams, Hadley cells, and the equator-to-pole temperature differences. Finally, we will discuss the implications for understanding how the atmospheric circulation influences the global-scale climate feedbacks that control the width of the habitable zone.

Showman, A. P.; Kaspi, Y.

2014-03-01

355

Identifying new opportunities for exoplanet characterisation at high spectral resolution  

CERN Document Server

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

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

2013-01-01

356

Probing the extended atmosphere of the evaporating exoplanet HD189733b  

Science.gov (United States)

HST observations show that two of the brightest transiting exoplanets are evaporating (HD209458b & HD189733b) and models suggest that the evolution of close-in planets may be dominated by this mass loss. X-ray observations during the transits of evaporating planets have the potential to detect absorption by the inner low-velocity regions of the planetary winds that are hidden to HST by interstellar absorption and geocoronal emission. Detections of these dense inner regions are needed in order to determine the dynamics of the planetary outflow and measure the mass loss rates. We propose an intense campaign of XMM-Newton transit observations of the most favourable target, HD189733b, with the aim of detecting the extended atmosphere of the planet and measuring its mass loss rate.

Wheatley, Peter

2013-10-01

357

Galactic cosmic ray induced radiation dose on terrestrial exoplanets  

CERN Document Server

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

Atri, Dimitra; Griessmeier, Jean-Mathias

2013-01-01

358

The effects of stellar winds and magnetic fields on exoplanets  

CERN Document Server

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

Vidotto, A A

2013-01-01

359

MASS-RADIUS RELATIONSHIPS FOR EXOPLANETS  

Energy Technology Data Exchange (ETDEWEB)

For planets other than Earth, particularly exoplanets, interpretation of the composition and structure depends largely on comparing the mass and radius with the composition expected given their distance from the parent star. The composition implies a mass-radius relation which relies heavily on equations of state calculated from electronic structure theory and measured experimentally on Earth. We lay out a method for deriving and testing equations of state, and deduce mass-radius and mass-pressure relations for key, relevant materials whose equation of state (EOS) is reasonably well established, and for differentiated Fe/rock. We find that variations in the EOS, such as may arise when extrapolating from low-pressure data, can have significant effects on predicted mass-radius relations and on planetary pressure profiles. The relations are compared with the observed masses and radii of planets and exoplanets, broadly supporting recent inferences about exoplanet structures. Kepler-10b is apparently 'Earth-like', likely with a proportionately larger core than Earth's, nominally 2/3 of the mass of the planet. CoRoT-7b is consistent with a rocky mantle over an Fe-based core which is likely to be proportionately smaller than Earth's. GJ 1214b lies between the mass-radius curves for H{sub 2}O and CH{sub 4}, suggesting an 'icy' composition with a relatively large core or a relatively large proportion of H{sub 2}O. CoRoT-2b is less dense than the hydrogen relation, which could be explained by an anomalously high degree of heating or by higher than assumed atmospheric opacity. HAT-P-2b is slightly denser than the mass-radius relation for hydrogen, suggesting the presence of a significant amount of matter of higher atomic number. CoRoT-3b lies close to the hydrogen relation. The pressure at the center of Kepler-10b is 1.5{sup +1.2}{sub -1.0} TPa. The central pressure in CoRoT-7b is probably close to 0.8 TPa, though may be up to 2 TPa. These pressures are accessible by planar shock and ramp-loading experiments at large laser facilities. The center of HAT-P-2b is probably around 210 TPa, in the range of planned National Ignition Facility experiments, and that of CoRoT-3b around 1900 TPa.

Swift, D. C.; Eggert, J. H.; Hicks, D. G.; Hamel, S.; Caspersen, K.; Schwegler, E.; Collins, G. W. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California, CA 94550 (United States); Nettelmann, N. [Institut fuer Physik, Universitaet Rostock, D-18051 Rostock (Germany); Ackland, G. J. [Centre for Science at Extreme Conditions, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)

2012-01-01

360

Exoplanet Habitability: Effects of Planetesimal Carbon Chemistry  

Science.gov (United States)

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

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

2014-05-01

 
 
 
 
361

Exomol: Molecular Line Lists for Exoplanet and Other Atmospheres  

Science.gov (United States)

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

Tennyson, Jonathan

2013-06-01

362

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

CERN Document Server

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

Johnson, Robert E; Erwin, Justin T

2013-01-01

363

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

DEFF Research Database (Denmark)

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

NØrgaard-Nielsen, Hans Ulrik

2012-01-01

364

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

CERN Document Server

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

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

2012-01-01

365

Observing Exoplanets with the James Webb Space Telescope  

Science.gov (United States)

The search for exoplanets and characterization of their properties has seen increasing success over the last few years. In excess of 500 exoplanets are known and Kepler has approx. 1000 additional candidates. Recently, progress has been made in direct imaging planets, both from the ground and in space. This presentation will discuss the history and current state of technology used for such discoveries, and highlight the new capabilities that will be enabled by the James Webb Space Telescope.

Clampin Mark

2011-01-01

366

Fundamental Parameters of Exoplanets and Their Host Stars  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 t...

Coughlin, Jeffrey L.

2013-01-01

367

Clouds and Hazes in Exoplanet Atmospheres  

CERN Document Server

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

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

2013-01-01

368

COMPLETENESS OF IMAGING SURVEYS FOR ECCENTRIC EXOPLANETS  

Energy Technology Data Exchange (ETDEWEB)

The detection of exoplanets through direct imaging has produced numerous new positive identifications in recent years. The technique is biased toward planets at wide separations due to the difficulty in removing the stellar signature at small angular separations. Planets in eccentric orbits will thus move in and out of the detectable region around a star as a function of time. Here we use the known diversity of orbital eccentricities to determine the range of orbits that may lie beneath the detection threshold of current surveys. We quantify the percentage of the orbit that yields a detectable signature as a function of semimajor axis, eccentricity, and orbital inclination and estimate the fraction of planets which likely remain hidden by the flux of the host star.

Kane, Stephen R., E-mail: skane@ipac.caltech.edu [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)

2013-03-20

369

Doppler Imaging of Exoplanets and Brown Dwarfs  

CERN Document Server

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

Crossfield, Ian J M

2014-01-01

370

Investigating nearby exoplanets via interstellar radar  

Science.gov (United States)

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

Scheffer, Louis K.

2014-01-01

371

Spin states and climates of eccentric exoplanets  

Science.gov (United States)

The known extrasolar planets exhibit a wide range of orbital eccentricities e. This has a profound influence on their rotations and climates. Because of tides in their interiors, mostly solid exoplanets are expected eventually to despin to a state of spin-orbit resonance, where the orbital period is some integer or half-integer times the rotation period. The most important of these resonances is the synchronous state, where the planet's spin period exactly equals its orbital period (like Earth's Moon, and indeed most of the regular satellites in the Solar System). Such planets seem doomed to roast on one side and freeze on the other. However, synchronous planets rock back and forth by an angle of ˜2Arcsine with respect to the sub-stellar point. For e=0.055 (as for the Moon), this optical libration amounts to only ˜6°; but for a synchronous planet with e=0.50, for example, it would rise to ˜59°. This greatly expands the temperate "twilight zone" near the terminator and considerably improves the planet's prospects for habitability. For e?0.72389, the optical libration exceeds 90°; for such planets, the sector of permanent night vanishes, while the sunniest region splits in two. Furthermore, the synchronous state is not the only possible spin resonance. For example, Mercury (with e?0.206) has an orbital period exactly 1.5 times its rotation period. A terrestrial exoplanet with e=0.40, say, is liable to have an orbital period of 2.0, 2.5, or 3.0 times its spin period. The corresponding insolation patterns are generally complicated, and all different from the synchronous state. Yet these non-synchronous resonances also protect certain longitudes from the worst extremes of temperature and solar radiation, and improve the planet's habitability, compared to non-resonant rotation. These results also have implications for the direct detectability of extrasolar planets, and the interpretation of their thermal emissions.

Dobrovolskis, Anthony R.

2007-12-01

372

LEECH: LBTI Exozodi Exoplanet Common Hunt  

Science.gov (United States)

We propose to perform a direct exoplanet imaging survey around nearby (3?m), where old/cool planets are brightest, and adaptive optics performance is superb (>95% Strehl ratio for LBTAO). The proposed survey will leverage 60 nights already-allocated to the NASA LBTI exozodiacal dust survey, which will target nearby stars with nulling interferometry to search for faint, warm debris disks. LBTI has a 3-5?m imager/spectrograph (LMIRCam) and an 8-13?m imager/spectrograph/nuller (NOMIC), which can be operated simultaneously using a beamsplitter, meaning that LMIRCam can search for gas-giant planets while NOMIC measures exozodiacal emission. Executing these two surveys simultaneously will greatly increase the scientific productivity of 60 already-allocated NASA nights by 1) creating exoplanet discovery opportunities and 2) providing a synergetic data set for studying debris disks (exozodis) as signposts of giant planets. The exozodi survey sample is older than the samples of other planned direct imaging surveys, which look at younger stars (searches, Spitzer and Herschel debris disk observations, and the concurrent LBTI exozodiacal dust survey). The combination of all of these data will reveal the overall architectures of planetary systems by constraining the presence of inner giant planets with RV data, outer giant planets with LBTI direct imaging, hot debris disks with LBTI exozodi data, and cold debris disks with Spitzer and Herschel. Based on planet population models and on-sky estimates of the LBTAO/LBTI instrument performance, we expect to discover ~2-7 planets by observing 117 nearby stars over the next 4 years. These planets will be older and nearer to the Sun than planets found by other surveys, and will benefit from synergetic data from several other surveys that target the nearest stars. Using these new discoveries, we will constrain the atmospheric and evolutionary models for intermediate-aged planets, and determine the extent to which debris