Publications (19)
Thermal escape from extrasolar giant planets
T. T. Koskinen, P. Lavvas, M. J. Harris +1
The detection of hot atomic hydrogen and heavy atoms and ions at high altitudes around close-in extrasolar giant planets (EGPs) such as HD209458b imply that these planets have hot…
Pluto's atmosphere observations with ALMA: spatially-resolved maps of CO and HCN emission and first detection of HNC
E. Lellouch, B. Butler, R. Moreno +6
Following the detection of CO and HCN in Pluto's atmosphere, we report on new ALMA observations of Pluto with two main goals: (i) obtaining spatially-resolved measurements (~0.06''…
Titan's lakes chemical composition: sources of uncertainties and variability
D. Cordier, O. Mousis, J. I. Lunine +5
Between 2004 and 2007 the instruments of the CASSINI spacecraft discovered hydrocarbon lakes in the polar regions of Titan. We have developed a lake-atmosphere equilibrium model al…
Detection of CO and HCN in Pluto's atmosphere with ALMA
E. Lellouch, M. Gurwell, B. Butler +16
Observations of the Pluto-Charon system, acquired with the ALMA interferometer on June 12-13, 2015, have yielded a detection of the CO(3-2) and HCN(4-3) rotational transitions from…
Characterizing the thermosphere of HD209458b with UV transit observations
T. T. Koskinen, R. V. Yelle, P. Lavvas +1
Transmission spectroscopy at UV wavelengths is a rich and largely unexplored source of information about the upper atmospheres of extrasolar planets. So far, UV transit observation…
The escape of heavy atoms from the ionosphere of HD209458b. II. Interpretation of the observations
T. T. Koskinen, R. V. Yelle, M. J. Harris +1
Transits in the H I 1216 A (Lyman alpha), O I 1334 A, C II 1335 A, and Si III 1206.5 A lines constrain the properties of the upper atmosphere of HD209458b. In addition to probing t…
The escape of heavy atoms from the ionosphere of HD209458b. I. A photochemical-dynamical model of the thermosphere
T. T. Koskinen, M. J. Harris, R. V. Yelle +1
The detections of atomic hydrogen, heavy atoms and ions surrounding the extrasolar giant planet (EGP) HD209458b constrain the composition, temperature and density profiles in its u…
An estimate of the chemical composition of Titan's lakes
D. Cordier, O. Mousis, J. -I. Lunine +2
Hundreds of radar-dark patches interpreted as lakes have been discovered in the north and south polar regions of Titan. We have estimated the composition of these lakes by using th…
About the possible role of hydrocarbon lakes in the origin of Titan's noble gas atmospheric depletion
D. Cordier, O. Mousis, J. I. Lunine +4
An unexpected feature of Titan's atmosphere is the strong depletion in primordial noble gases revealed by the Gas Chromatograph Mass Spectrometer aboard the Huygens probe during it…
Hubble PanCET: An extended upper atmosphere of neutral hydrogen around the warm Neptune GJ 3470 b
V. Bourrier, A. Lecavelier des Etangs, D. Ehrenreich +16
GJ 3470b is a warm Neptune transiting an M-dwarf star at the edge of the evaporation desert. It offers the possibility of investigating how low-mass, close-in exoplanets evolve und…
Seasonal variation of Saturn's Lyman- brightness
P. Stephenson, T. T. Koskinen, Z. Brown +5
We examine Saturn's non-auroral (dayglow) emissions at Lyman- observed by the {Cassini/UVIS} instrument from 2004 until 2016, to constrain meridional and seasonal trends in the…
The Hubble PanCET program: Long-term chromospheric evolution and flaring activity of the M dwarf host GJ 3470
V. Bourrier, L. A. dos Santos, J. Sanz-Forcada +9
Neptune-size exoplanets seem particularly sensitive to atmospheric evaporation, making it essential to characterize the stellar high-energy radiation that drives this mechanism. Th…
Electrodynamics on extrasolar giant planets
T. T. Koskinen, R. V. Yelle, P. Lavvas +1
Strong ionization on close-in extrasolar giant planets suggests that their atmospheres may be affected by ion drag and resistive heating arising from wind-driven electrodynamics. R…
Energy deposition in Saturn's equatorial upper atmosphere
J. M. Chadney, T. T. Koskinen, X. Hu +6
We construct Saturn equatorial neutral temperature and density profiles of H, H, He, and CH, between 10 and 1 bar using measurements from Cassini's Ion Neutral Mass…
The Hubble PanCET program: An extensive search for metallic ions in the exosphere of GJ 436 b
L. A. dos Santos, D. Ehrenreich, V. Bourrier +15
(Abridged) The quiet M2.5 star GJ 436 hosts a warm Neptune that displays an extended atmosphere that dwarfs its own host star. Predictions of atmospheric escape in such planets sta…
An unidentified absorption feature at 5.11 m on the surface of Titan and Pluto from JWST spectroscopy
B. Bézard, E. Lellouch, M. Camarca +14
Titan possesses a thick N-CH atmosphere that makes it difficult to study its surface spectroscopically. The chemical composition of the solid surface of Titan thus remains…
HST PanCET program: A Cloudy Atmosphere for the promising JWST target WASP-101b
H. R. Wakeford, K. B. Stevenson, N. K. Lewis +19
We present results from the first observations of the Hubble Space Telescope (HST) Panchromatic Comparative Exoplanet Treasury (PanCET) program for WASP-101b, a highly inflated hot…
HST PanCET program: Non-detection of atmospheric escape in the warm Saturn-sized planet WASP-29 b
L. A. dos Santos, V. Bourrier, D. Ehrenreich +10
(Abridged) Short-period gas giant exoplanets are susceptible to intense atmospheric escape due to their large scale heights and strong high-energy irradiation. This process is thou…
The atmosphere of K2-18 b: The role of hazes, clouds and photoelectrons
P. Lavvas, R. Liu, G. Tinetti +3
The atmospheric characterisation of temperate exoplanets is becoming accessible with JWST, providing a critical connection between Solar System planets and the more commonly observ…