Search Publications
Radar evidence of subglacial liquid water on Mars
Pajola, M.; Lauro, S. E.; Pettinelli, E. +19 more
The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 20…
A Population Study of Gaseous Exoplanets
Tsiaras, A.; Waldmann, I. P.; Rocchetto, M. +8 more
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 t…
Revised Radii of Kepler Stars and Planets Using Gaia Data Release 2
van Saders, Jennifer L.; Huber, Daniel; Berger, Travis A. +1 more
One bottleneck for the exploitation of data from the Kepler mission for stellar astrophysics and exoplanet research has been the lack of precise radii and evolutionary states for most of the observed stars. We report revised radii of 177,911 Kepler stars derived by combining parallaxes from the Gaia Data Release 2 with the DR25 Kepler Stellar Prop…
The APOGEE-2 Survey of the Orion Star-forming Complex. II. Six-dimensional Structure
Da Rio, Nicola; Pan, Kaike; Kounkel, Marina +17 more
We present an analysis of spectroscopic and astrometric data from APOGEE-2 and Gaia DR2 to identify structures toward the Orion Complex. By applying a hierarchical clustering algorithm to the six-dimensional stellar data, we identify spatially and/or kinematically distinct groups of young stellar objects with ages ranging from 1 to 12 Myr. We also…
Beyond the Required LISA Free-Fall Performance: New LISA Pathfinder Results down to 20 µ Hz
Mendes, L.; Russano, G.; Lloro, I. +75 more
In the months since the publication of the first results, the noise performance of LISA Pathfinder has improved because of reduced Brownian noise due to the continued decrease in pressure around the test masses, from a better correction of noninertial effects, and from a better calibration of the electrostatic force actuation. In addition, the ava…
Evidence for a Systematic Offset of -80 µas in the Gaia DR2 Parallaxes
Torres, Guillermo; Stassun, Keivan G.
We reprise the analysis of Stassun & Torres, comparing the parallaxes of the eclipsing binaries reported in that paper to the parallaxes newly reported in the Gaia second data release (DR2). We find evidence for a systematic offset of -82 ± 33 µas, in the sense of the Gaia parallaxes being too small, for brightnesses (G ≲ 12) and for dis…
The nature of the TRAPPIST-1 exoplanets
Triaud, Amaury H. M. J.; Burgasser, Adam J.; Gillon, Michaël +23 more
Context. The TRAPPIST-1 system hosts seven Earth-sized, temperate exoplanets orbiting an ultra-cool dwarf star. As such, it represents a remarkable setting to study the formation and evolution of terrestrial planets that formed in the same protoplanetary disk. While the sizes of the TRAPPIST-1 planets are all known to better than 5% precision, the…
Kinematic Evidence for an Embedded Protoplanet in a Circumstellar Disk
Pinte, C.; Ménard, F.; Duchêne, G. +6 more
Disks of gas and dust surrounding young stars are the birthplace of planets. However, the direct detection of protoplanets forming within disks has proved elusive to date. We present the detection of a large, localized deviation from Keplerian velocity in the protoplanetary disk surrounding the young star HD 163296. The observed velocity pattern i…
A Kinematical Detection of Two Embedded Jupiter-mass Planets in HD 163296
Foreman-Mackey, Daniel; Bae, Jaehan; Bergin, Edwin A. +2 more
We present the first kinematical detection of embedded protoplanets within a protoplanetary disk. Using archival Atacama Large Millimetre Array (ALMA) observations of HD 163296, we demonstrate a new technique to measure the rotation curves of CO isotopologue emission to sub-percent precision relative to the Keplerian rotation. These rotation curve…
The outflow structure of GW170817 from late-time broad-band observations
Troja, E.; Piro, L.; van Eerten, H. +6 more
We present our broad-band study of GW170817 from radio to hard X-rays, including NuSTAR and Chandra observations up to 165 d after the merger, and a multimessenger analysis including LIGO constraints. The data are compared with predictions from a wide range of models, providing the first detailed comparison between non-trivial cocoon and jet model…