A Population Study of Gaseous Exoplanets

We present here the analysis of 30 gaseous extrasolar planets, with temperatures between 600 and 2400 K and radii between 0.35 and 1.9 R Jup. The quality of the HST/WFC3 spatially scanned data combined with our specialized analysis tools allow us to study the largest and most self-consistent sample of exoplanetary transmission spectra to date and examine the collective behavior of warm and hot gaseous planets rather than isolated case studies. We define a new metric, the Atmospheric Detectability Index (ADI) to evaluate the statistical significance of an atmospheric detection and find statistically significant atmospheres in around 16 planets out of the 30 analyzed. For most of the Jupiters in our sample, we find the detectability of their atmospheres to be dependent on the planetary radius but not on the planetary mass. This indicates that planetary gravity plays a secondary role in the state of gaseous planetary atmospheres. We detect the presence of water vapour in all of the statistically detectable atmospheres, and we cannot rule out its presence in the atmospheres of the others. In addition, TiO and/or VO signatures are detected with 4σ confidence in WASP-76 b, and they are most likely present in WASP-121 b. We find no correlation between expected signal-to-noise and atmospheric detectability for most targets. This has important implications for future large-scale surveys.

[1]  A. Tsiaras,et al.  Wayne—A Simulator for HST WFC3 IR Grism Spectroscopy , 2015, 1511.09108.

[2]  N. Santos,et al.  Near-infrared transmission spectrum of the warm-uranus GJ 3470b with the Wide Field Camera-3 on the Hubble Space Telescope , 2014, 1405.1056.

[3]  Mark R. Swain,et al.  0.94–2.42 μm GROUND-BASED TRANSMISSION SPECTRA OF THE HOT JUPITER HD-189733b , 2013 .

[4]  Andreas Seifahrt,et al.  TRANSMISSION SPECTROSCOPY OF THE HOT JUPITER WASP-12b FROM 0.7 TO 5 μm , 2013, 1305.1670.

[5]  D. Queloz,et al.  A global analysis of Spitzer and new HARPS data confirms the loneliness and metal-richness of GJ 436 b , 2014, 1409.4038.

[6]  Jacob L. Bean,et al.  HUBBLE SPACE TELESCOPE NEAR-IR TRANSMISSION SPECTROSCOPY OF THE SUPER-EARTH HD 97658B , 2014, 1403.4602.

[7]  K. Heng,et al.  ATMOSPHERIC RETRIEVAL ANALYSIS OF THE DIRECTLY IMAGED EXOPLANET HR 8799b , 2013, 1307.1404.

[8]  A. Pine.  Self‐, N2, O2, H2, Ar, and He broadening in the ν3 band Q branch of CH4 , 1992 .

[9]  Jonathan Tennyson,et al.  HITEMP, the high-temperature molecular spectroscopic database , 2010 .

[10]  Vivien Parmentier,et al.  TRANSITIONS IN THE CLOUD COMPOSITION OF HOT JUPITERS , 2016, 1602.03088.

[11]  Gregory Laughlin,et al.  ON THE ANOMALOUS RADII OF THE TRANSITING EXTRASOLAR PLANETS , 2011, 1101.5827.

[12]  Sergei N. Yurchenko,et al.  ExoMol line lists IV: The rotation-vibration spectrum of methane up to 1500 K , 2014, 1401.4852.

[13]  Carnegie,et al.  HAT-P-1b: A Large-Radius, Low-Density Exoplanet Transiting One Member of a Stellar Binary* ** , 2007 .

[14]  Jacob L. Bean,et al.  A DETECTION OF WATER IN THE TRANSMISSION SPECTRUM OF THE HOT JUPITER WASP-12b AND IMPLICATIONS FOR ITS ATMOSPHERIC COMPOSITION , 2015, 1504.05586.

[15]  Drake Deming,et al.  EXOPLANET TRANSIT SPECTROSCOPY USING WFC3: WASP-12 b, WASP-17 b, AND WASP-19 b , 2013, 1310.2949.

[16]  R. G. West,et al.  WASP-52b, WASP-58b, WASP-59b, and WASP-60b: four new transiting close-in giant planets , 2012, 1211.0810.

[17]  Bernhard Brandl,et al.  The fast spin-rotation of a young extra-solar planet , 2014 .

[18]  M. Bonnefoy,et al.  HELIOS–RETRIEVAL: An Open-source, Nested Sampling Atmospheric Retrieval Code; Application to the HR 8799 Exoplanets and Inferred Constraints for Planet Formation , 2016, 1610.03216.

[19]  Drake Deming,et al.  A spectrum of an extrasolar planet , 2007, Nature.

[20]  Sara Seager,et al.  A PRECISE WATER ABUNDANCE MEASUREMENT FOR THE HOT JUPITER WASP-43b , 2014, 1410.2255.

[21]  J. Fortney,et al.  UNDERSTANDING THE MASS–RADIUS RELATION FOR SUB-NEPTUNES: RADIUS AS A PROXY FOR COMPOSITION , 2013, 1311.0329.

[22]  Bruce A. Macintosh,et al.  Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet Atmosphere , 2013, Science.

[23]  Gautam Vasisht,et al.  The presence of methane in the atmosphere of an extrasolar planet , 2008, Nature.

[24]  A. Santerne,et al.  WASP-121 b: a hot Jupiter close to tidal disruption transiting an active F star , 2015, 1506.02471.

[25]  R. G. West,et al.  Three irradiated and bloated hot Jupiters:. WASP-76b, WASP-82b, and WASP-90b , 2013, 1310.5607.

[26]  Z. Csubry,et al.  HAT-P-38b : A Saturn-Mass Planet Transiting a Late G Star , 2012, 1201.5075.

[27]  I. P. Waldmann,et al.  REVISITING SPITZER TRANSIT OBSERVATIONS WITH INDEPENDENT COMPONENT ANALYSIS: NEW RESULTS FOR THE GJ 436 SYSTEM , 2015, 1501.05866.

[28]  A. Erikson,et al.  The effect of stellar limb darkening values on the accuracy of the planet radii derived from photometric transit observations , 2012, 1212.2372.

[29]  Jonathan Tennyson,et al.  TAU-REX I: A NEXT GENERATION RETRIEVAL CODE FOR EXOPLANETARY ATMOSPHERES , 2014, 1409.2312.

[30]  S. Aigrain,et al.  Hst hot jupiter transmission spectral survey: Detection of water in HAT-P-1b from WFC3 near-IR spatial scan observations , 2013, 1308.2106.

[31]  C. Griffith,et al.  Disentangling degenerate solutions from primary transit and secondary eclipse spectroscopy of exoplanets , 2013, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[32]  Geza Kovacs,et al.  HAT-P-17b,c: A TRANSITING, ECCENTRIC, HOT SATURN AND A LONG-PERIOD, COLD JUPITER , 2010, The Astrophysical Journal.

[33]  I. P. Waldmann,et al.  EXPLORING BIASES OF ATMOSPHERIC RETRIEVALS IN SIMULATED JWST TRANSMISSION SPECTRA OF HOT JUPITERS , 2016, 1610.02848.

[34]  Ahmed F. Al-Refaie,et al.  The ExoMol database: Molecular line lists for exoplanet and other hot atmospheres , 2016, 1603.05890.

[35]  Bernhard R. Brandl,et al.  Fast spin of the young extrasolar planet β Pictoris b , 2014, Nature.

[36]  T. Barman,et al.  Warm ice giant GJ 3470b - II. Revised planetary and stellar parameters from optical to near-infrared transit photometry , 2014, 1406.6437.

[37]  R. G. West,et al.  THREE WASP-SOUTH TRANSITING EXOPLANETS: WASP-74b, WASP-83b, AND WASP-89b , 2014, 1410.6358.

[38]  J. Fortney,et al.  THE FLAT TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ1214b FROM WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE , 2011, 1111.5621.

[39]  J. Tennyson,et al.  A high-accuracy computed water line list , 2006, astro-ph/0601236.

[40]  HAT-P-26b: A LOW-DENSITY NEPTUNE-MASS PLANET TRANSITING A K STAR* , 2010, 1010.1008.

[41]  Jacob L. Bean,et al.  An Observational Diagnostic for Distinguishing between Clouds and Haze in Hot Exoplanet Atmospheres , 2017, 1705.05847.

[42]  K. Lodders,et al.  ATMOSPHERIC SULFUR PHOTOCHEMISTRY ON HOT JUPITERS , 2009, 0903.1663.

[43]  David Charbonneau,et al.  The 3.6-8.0 μm Broadband Emission Spectrum of HD 209458b: Evidence for an Atmospheric Temperature Inversion , 2007, 0709.3984.

[44]  Jason J. Wang,et al.  Discovery and spectroscopy of the young jovian planet 51 Eri b with the Gemini Planet Imager , 2015, Science.

[45]  Michael R. Line,et al.  THE INFLUENCE OF NONUNIFORM CLOUD COVER ON TRANSIT TRANSMISSION SPECTRA , 2015, 1511.09443.

[46]  Joanna K. Barstow,et al.  Constraining the atmosphere of GJ 1214b using an optimal estimation technique , 2013, 1306.6567.

[47]  Laura K. McKemmish,et al.  ExoMol line lists – XVIII. The high-temperature spectrum of VO , 2016, 1609.06120.

[48]  F. Allard,et al.  Models of very-low-mass stars, brown dwarfs and exoplanets , 2011, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[49]  Jonathan Tennyson,et al.  Water vapour in the atmosphere of a transiting extrasolar planet , 2007, Nature.

[50]  Mark Clampin,et al.  INFRARED TRANSMISSION SPECTROSCOPY OF THE EXOPLANETS HD 209458b AND XO-1b USING THE WIDE FIELD CAMERA-3 ON THE HUBBLE SPACE TELESCOPE , 2013, 1302.1141.

[51]  J. Tennyson,et al.  A variationally computed line list for hot NH3 , 2010, 1011.1569.

[52]  M. Barbieri,et al.  The GAPS Programme with HARPS-N at TNG. III: The retrograde orbit of HAT-P-18b , 2014, 1403.6728.

[53]  Sara Seager,et al.  Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy , 2014, Science.

[54]  Angelos Tsiaras,et al.  High-precision Stellar Limb-darkening in Exoplanetary Transits , 2017, 1704.08232.

[55]  R. G. West,et al.  Transiting hot Jupiters from WASP-South, Euler and TRAPPIST : WASP-95b to WASP-101b , 2013, 1310.5630.

[56]  Drake Deming,et al.  A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion , 2016, Nature.

[57]  Carl J. Grillmair,et al.  Strong water absorption in the dayside emission spectrum of the planet HD 189733b , 2008, Nature.

[58]  S. Aigrain,et al.  HST hot-Jupiter transmission spectral survey: detection of potassium in WASP-31b along with a cloud deck and Rayleigh scattering , 2014, 1410.7611.

[59]  I. P. Waldmann,et al.  A NEW APPROACH TO ANALYZING HST SPATIAL SCANS: THE TRANSMISSION SPECTRUM OF HD 209458 b , 2015, 1511.07796.

[60]  L. Koesterke,et al.  Sodium Absorption from the Exoplanetary Atmosphere of HD 189733b Detected in the Optical Transmission Spectrum , 2007, 0712.0761.

[61]  Models of Stars, Brown Dwarfs and Exoplanets , 2011 .

[62]  HighWire Press.  Philosophical Transactions of the Royal Society of London , 1781, The London Medical Journal.

[63]  UC Berkeley,et al.  HAT-P-12b: A LOW-DENSITY SUB-SATURN MASS PLANET TRANSITING A METAL-POOR K DWARF , 2009, 0904.4704.

[64]  F. Feroz,et al.  MultiNest: an efficient and robust Bayesian inference tool for cosmology and particle physics , 2008, 0809.3437.

[65]  J. Skilling.  Nested sampling for general Bayesian computation , 2006 .

[66]  G. Tinetti,et al.   ?> -REx. II. RETRIEVAL OF EMISSION SPECTRA , 2015, 1508.07591.

[67]  J. Tennyson,et al.  DETECTION OF AN ATMOSPHERE AROUND THE SUPER-EARTH 55 CANCRI E , 2015, 1511.08901.

[68]  J. Livingston,et al.  A CHARACTERISTIC TRANSMISSION SPECTRUM DOMINATED BY H2O APPLIES TO THE MAJORITY OF HST/WFC3 EXOPLANET OBSERVATIONS , 2015, 1512.00151.

[69]  U. Jørgensen,et al.  High-temperature (1000–7000 K) collision-induced absorption of H2 pairs computed from the first principles, with application to cool and dense stellar atmospheres , 2001 .

[70]  Nikku Madhusudhan,et al.  NO THERMAL INVERSION AND A SOLAR WATER ABUNDANCE FOR THE HOT JUPITER HD 209458B FROM HST/WFC3 SPECTROSCOPY , 2016, 1605.08810.

[71]  B. J. Fulton,et al.  HAT-P-39b–HAT-P-41b: THREE HIGHLY INFLATED TRANSITING HOT JUPITERS , 2012, 1207.3344.

[72]  T. Zingales,et al.  Near-IR Transmission Spectrum of HAT-P-32b using HST/WFC3 , 2017, 1802.10010.

[73]  J. Barstow,et al.  HST PanCET Program: A Cloudy Atmosphere for the Promising JWST Target WASP-101b , 2017, 1701.00843.

[74]  N. Crouzet,et al.  WATER VAPOR IN THE SPECTRUM OF THE EXTRASOLAR PLANET HD 189733b. I. THE TRANSIT , 2014, 1407.2462.

[75]  J. Fortney,et al.  THE ATMOSPHERIC CHEMISTRY OF GJ 1214b: PHOTOCHEMISTRY AND CLOUDS , 2011, 1104.5477.

[76]  Drake Deming,et al.  Water vapour absorption in the clear atmosphere of a Neptune-sized exoplanet , 2014, Nature.

[77]  Nikole K. Lewis,et al.  WARM SPITZER PHOTOMETRY OF THREE HOT JUPITERS: HAT-P-3b, HAT-P-4b AND HAT-P-12b , 2013, 1305.0833.

[78]  A. Mandell,et al.  MARGINALIZING INSTRUMENT SYSTEMATICS IN HST WFC3 TRANSIT LIGHT CURVES , 2016, 1601.02587.

[79]  Michitoshi Yoshida,et al.  OPTICAL-TO-NEAR-INFRARED SIMULTANEOUS OBSERVATIONS FOR THE HOT URANUS GJ3470b: A HINT OF A CLOUD-FREE ATMOSPHERE , 2013, 1302.7257.

[80]  Drake Deming,et al.  Clouds in the atmosphere of the super-Earth exoplanet GJ 1214b , 2013, Nature.

[81]  D. Ehrenreich,et al.  WASP-80b has a dayside within the T-dwarf range ? , 2015, 1503.08152.

[82]  Christoph Mordasini,et al.  A FRAMEWORK FOR CHARACTERIZING THE ATMOSPHERES OF LOW-MASS LOW-DENSITY TRANSITING PLANETS , 2013, 1306.4329.

[83]  Yifan Zhou,et al.  A Physical Model-based Correction for Charge Traps in the Hubble Space Telescope’s Wide Field Camera 3 Near-IR Detector and Its Applications to Transiting Exoplanets and Brown Dwarfs , 2017, 1703.01301.

[84]  L. Rogers.  MOST 1.6 EARTH-RADIUS PLANETS ARE NOT ROCKY , 2014, 1407.4457.

[85]  M. Holman,et al.  Accepted for publication in The Astrophysical Journal Preprint typeset using L ATEX style emulateapj v. 10/09/06 IMPROVED PARAMETERS FOR EXTRASOLAR TRANSITING PLANETS , 2008 .

[86]  R. J. de Kok,et al.  DETECTION OF MOLECULAR ABSORPTION IN THE DAYSIDE OF EXOPLANET 51 PEGASI b? , 2013, 1302.6242.

[87]  D. W. Latham,et al.  HAT-P-32b AND HAT-P-33b: TWO HIGHLY INFLATED HOT JUPITERS TRANSITING HIGH-JITTER STARS , 2011, 1106.1212.

[88]  I. Howarth,et al.  Rapid rotators revisited: absolute dimensions of KOI-13 , 2017, 1705.07302.

[89]  James F. Kasting,et al.  A PHOTOCHEMICAL MODEL FOR THE CARBON-RICH PLANET WASP-12b , 2011, 1110.2793.

[90]  I. Howarth.  New limb-darkening coefficients and synthetic photometry for model-atmosphere grids at Galactic, LMC and SMC abundances , 2010, 1011.2631.

[91]  Drake Deming,et al.  A featureless transmission spectrum for the Neptune-mass exoplanet GJ 436b , 2014, Nature.

[92]  Sara Seager,et al.  ATMOSPHERIC RETRIEVAL FOR SUPER-EARTHS: UNIQUELY CONSTRAINING THE ATMOSPHERIC COMPOSITION WITH TRANSMISSION SPECTROSCOPY , 2012, 1203.4018.

[93]  Simon Albrecht,et al.  Detection of carbon monoxide in the high-resolution day-side spectrum of the exoplanet HD 189733b , 2013, 1304.4014.

[94]  UC Berkeley,et al.  HAT-P-11b: A SUPER-NEPTUNE PLANET TRANSITING A BRIGHT K STAR IN THE KEPLER FIELD , 2009, 0901.0282.

[95]  M. Asplund,et al.  Limb darkening laws for two exoplanet host stars derived from 3D stellar model atmospheres Comparison with 1D models and HST light curve observations , 2012, 1202.0548.

[96]  F. Selsis,et al.  Inferring heat recirculation and albedo for exoplanetary atmospheres: Comparing optical phase curves and secondary eclipse data , 2015, 1512.04908.

[97]  Howard Isaacson,et al.  THE MASS OF KOI-94d AND A RELATION FOR PLANET RADIUS, MASS, AND INCIDENT FLUX , 2013, 1303.2150.

[98]  A. Borysow,et al.  Collision-induced absorption coefficients of H2 pairs at temperatures from 60 K to 1000 K , 2002 .

[99]  R. Gilliland,et al.  Detection of an Extrasolar Planet Atmosphere , 2001, astro-ph/0111544.

[100]  Robert T. Zellem,et al.  THE GROUND-BASED H-, K-, AND L-BAND ABSOLUTE EMISSION SPECTRA OF HD 209458b , 2014, 1409.8187.

[101]  T. Evans,et al.  DETECTION OF H2O AND EVIDENCE FOR TiO/VO IN AN ULTRA-HOT EXOPLANET ATMOSPHERE , 2016, 1604.02310.

[102]  R. G. West,et al.  Three newly discovered sub-Jupiter-mass planets: WASP-69b and WASP-84b transit active K dwarfs and WASP-70Ab transits the evolved primary of a G4+K3 binary † , 2013, 1310.5654.

[103]  R. G. West,et al.  WASP-39b: a highly inflated Saturn-mass planet orbiting a late G-type star , 2011, 1102.1375.

[104]  Keivan G. Stassun,et al.  TRANSIT TIMING VARIATION MEASUREMENTS OF WASP-12b AND QATAR-1b: NO EVIDENCE OF ADDITIONAL PLANETS , 2015, 1512.00464.

[105]  Björn Benneke,et al.  A map of the large day–night temperature gradient of a super-Earth exoplanet , 2016, Nature.

[106]  Drake Deming,et al.  Possible thermochemical disequilibrium in the atmosphere of the exoplanet GJ 436b , 2010, Nature.

[107]  R. MacDonald,et al.  HD 209458b in new light: evidence of nitrogen chemistry, patchy clouds and sub-solar water , 2017, 1701.01113.

[108]  Jacob L. Bean,et al.  A ground-based transmission spectrum of the super-Earth exoplanet GJ 1214b , 2010, Nature.

[109]  A. Burrows,et al.  THERMAL PROCESSES GOVERNING HOT-JUPITER RADII , 2013, 1303.0293.