Search Publications
The long egress of GJ 436b's giant exosphere
Heng, K.; Thomas, N.; Ehrenreich, D. +8 more
The M dwarf GJ 436 hosts a transiting warm Neptune known to experience atmospheric escape. Previous observations revealed the presence of a giant hydrogen exosphere transiting the star for more than 5 h, and absorbing up to 56% of the flux in the blue wing of the stellar Lyman-α line of neutral hydrogen (H I Lyα). The unexpected size of this comet…
DustPedia: A Definitive Study of Cosmic Dust in the Local Universe
Bianchi, S.; Smith, M.; Fritz, J. +20 more
The European Space Agency has invested heavily in two cornerstones missions: Herschel and Planck. The legacy data from these missions provides an unprecedented opportunity to study cosmic dust in galaxies so that we can, for example, answer fundamental questions about the origin of the chemical elements, physical processes in the interstellar medi…
The Galactic Center Molecular Cloud Survey. I. A steep linewidth-size relation and suppression of star formation
Lu, Xing; Menten, Karl M.; Zhang, Qizhou +4 more
The central molecular zone (CMZ; inner 200 pc) of the Milky Way is a star formation (SF) environment with very extreme physical properties. Exploration of SF in this region is important because (I) this region allows us to test models of star formation under exceptional conditions; and (II) the CMZ clouds might be suitable to serve as templates to…
Host galaxies of luminous z ∼ 0.6 quasars: major mergers are not prevalent at the highest AGN luminosities
Wuyts, S.; Fontana, A.; Trump, J. +10 more
Galaxy interactions are thought to be one of the main triggers of active galactic nuclei (AGN), especially at high luminosities, where the accreted gas mass during the AGN lifetime is substantial. Evidence for a connection between mergers and AGN, however, remains mixed. Possible triggering mechanisms remain particularly poorly understood for lumi…
Forward and Inverse Modeling of the Emission and Transmission Spectrum of GJ 436b: Investigating Metal Enrichment, Tidal Heating, and Clouds
Knutson, Heather; Fortney, Jonathan J.; Marley, Mark S. +5 more
The Neptune-mass GJ 436b is one of the most studied transiting exoplanets with repeated measurements of its thermal emission and transmission spectra. We build on previous studies to answer outstanding questions about this planet, including its potentially high metallicity and tidal heating of its interior. We present new observations of GJ 436b’s…
Revisiting the Tale of Hercules: How Stars Orbiting the Lagrange Points Visit the Sun
Gerhard, Ortwin; Pérez-Villegas, Angeles; Wegg, Christopher +1 more
We propose a novel explanation for the Hercules stream consistent with recent measurements of the extent and pattern speed of the Galactic bar. We have adapted a made-to-measure dynamical model tailored for the Milky Way to investigate the kinematics of the solar neighborhood (SNd). The model matches the 3D density of the red clump giant stars (RC…
A box full of chocolates: The rich structure of the nearby stellar halo revealed by Gaia and RAVE
Tian, Hao; Helmi, Amina; Sales, Laura V. +2 more
Context. The hierarchical structure formation model predicts that stellar halos should form, at least partly, via mergers. If this was a predominant formation channel for the Milky Way's halo, imprints of this merger history in the form of moving groups or streams should also exist in the vicinity of the Sun.
Aims: We study the kinematics of …
The State-of-the-art HST Astro-photometric Analysis of the Core of ω Centauri. I. The Catalog
Anderson, J.; Bedin, L. R.; King, I. R. +4 more
We have constructed the most comprehensive catalog of photometry and proper motions ever assembled for a globular cluster (GC). The core of ωCen has been imaged over 650 times through WFC3's UVIS and IR channels for the purpose of detector calibration. There exist from 4 to over 60 exposures through each of 26 filters stretching continuously from …
The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs at wide orbits. IV. Gravitational instability rarely forms wide, giant planets
Moutou, C.; Quanz, S. P.; Henning, T. +34 more
Understanding the formation and evolution of giant planets (≥1 MJup) at wide orbital separation (≥5 AU) is one of the goals of direct imaging. Over the past 15 yr, many surveys have placed strong constraints on the occurrence rate of wide-orbit giants, mostly based on non-detections, but very few have tried to make a direct link with pl…
The structure and variability of Mars dayside thermosphere from MAVEN NGIMS and IUVS measurements: Seasonal and solar activity trends in scale heights and temperatures
Stiepen, Arnaud; Schneider, Nicholas M.; Bougher, Stephen W. +10 more
Mars dayside thermospheric temperature and scale height trends were examined using measurements from the Neutral Gas Ion Mass Spectrometer (NGIMS) and the Imaging Ultraviolet Spectrograph (IUVS) on the Mars Atmosphere Volatile EvolutioN (MAVEN) spacecraft. Average scale heights (over 150-180 km for solar zenith angles ≤75°) from several different …