Search Publications
Unexpected increase of the deuterium to hydrogen ratio in the Venus mesosphere
Vandaele, Ann Carine; Robert, Séverine; Chamberlain, Sarah +14 more
Studying Venus's HDO and H2O sheds light on its water history. The HDO/H2O ratio in its bulk atmosphere, 120 times Earth's, suggests a significantly wetter past for Venus. Our study analyzes mesospheric (70 to 110 km) temperature, H2O, and HDO profiles taken in solar occultation by SOIR/Venus Express. We observe in…
The orbital eccentricity distribution of planets orbiting M dwarfs
Ballard, Sarah; Sagear, Sheila
The orbital eccentricities of exoplanets orbiting M dwarf stars may significantly affect their habitability but are unknown. We extract this eccentricity distribution using a sample of transiting planets orbiting M dwarfs detected by NASA's Kepler Mission with stellar density measurements. We find planets in apparently single-transiting systems ar…
The evolution of hot Jupiters revealed by the age distribution of their host stars
Huang, Yang; Dong, Subo; Luo, A. -Li +11 more
Hot Jupiters are the first exoplanet population discovered around main-sequence stars. However, their origin and evolution remain puzzled. Using a sample with kinematic properties derived from large surveys (e.g., Gaia, LAMOST), we characterize the kinematic ages of stars hosting hot and warm/cold Jupiters, confirming the result of the previous st…
Global-scale brittle plastic rheology at the cometesimals merging of comet 67P/Churyumov-Gerasimenko
Naletto, Giampiero; Francheschi, M.; Penasa, Luca +12 more
Growth model interpretation of planet size distribution
Vanderburg, Andrew; Cao, Hao; Berger, Travis A. +13 more
The radii and orbital periods of 4,000+ confirmed/candidate exoplanets have been precisely measured by the Kepler mission. The radii show a bimodal distribution, with two peaks corresponding to smaller planets (likely rocky) and larger intermediate-size planets, respectively. While only the masses of the planets orbiting the brightest stars can be…
Giant ripples on comet 67P/Churyumov-Gerasimenko sculpted by sunset thermal wind
Jia, Pan; Andreotti, Bruno; Claudin, Philippe
Explaining the unexpected presence of dune-like patterns at the surface of the comet 67P/Churyumov-Gerasimenko requires conceptual and quantitative advances in the understanding of surface and outgassing processes. We show here that vapor flow emitted by the comet around its perihelion spreads laterally in a surface layer, due to the strong pressu…
Titan solar occultation observations reveal transit spectra of a hazy world
Fortney, Jonathan J.; Maltagliati, Luca; Marley, Mark S. +1 more
High altitude clouds and hazes are integral to understanding exoplanet observations, and are proposed to explain observed featureless transit spectra. However, it is difficult to make inferences from these data because of the need to disentangle effects of gas absorption from haze extinction. Here, we turn to the quintessential hazy world -- Titan…
Orbital apocenter is not a sufficient condition for HST/STIS detection of Europa's water vapor aurora
Nimmo, Francis; Saur, Joachim; Roth, Lorenz +4 more
We report far-ultraviolet observations of Jupiter's moon Europa taken by Space Telescope Imaging Spectrograph (STIS) of the Hubble Space Telescope (HST) in January and February 2014 to test the hypothesis that the discovery of a water vapor aurora in December 2012 by local hydrogen (H) and oxygen (O) emissions with the STIS originated from plume a…
Seismic constraints on rotation of Sun-like star and mass of exoplanet
Auvergne, M.; Baudin, F.; Michel, E. +32 more
Rotation is thought to drive cyclic magnetic activity in the Sun and Sun-like stars. Stellar dynamos, however, are poorly understood owing to the scarcity of observations of rotation and magnetic fields in stars. Here, inferences are drawn on the internal rotation of a distant Sun-like star by studying its global modes of oscillation. We report as…
Ammonia clathrate hydrates as new solid phases for Titan, Enceladus, and other planetary systems
Kumar, R.; Shin, K.; Udachin, K. A. +2 more