Search Publications
Stellar and substellar companions from Gaia EDR3. Proper-motion anomaly and resolved common proper-motion pairs
Thévenin, Frédéric; Kervella, Pierre; Arenou, Frédéric
Context. The multiplicity fraction of stars, down to the substellar regime, is a parameter of fundamental importance for stellar formation, evolution, and planetology. The census of multiple stars in the solar neighborhood is however incomplete.
Aims: Our study is aimed at detecting companions of HIPPARCOS catalog stars from the proper motion…
3D Selection of 167 Substellar Companions to Nearby Stars
Butler, R. Paul; Vogt, Steven S.; Oppenheimer, Rebecca +20 more
We analyze 5108 AFGKM stars with at least five high-precision radial velocity points, as well as Gaia and Hipparcos astrometric data, utilizing a novel pipeline developed in previous work. We find 914 radial velocity signals with periods longer than 1000 days. Around these signals, 167 cold giants and 68 other types of companions are identified, t…
Direct-imaging Discovery and Dynamical Mass of a Substellar Companion Orbiting an Accelerating Hyades Sun-like Star with SCExAO/CHARIS
Currie, Thayne; Kwon, Jungmi; Tamura, Motohide +33 more
We present the direct-imaging discovery of a substellar companion in orbit around a Sun-like star member of the Hyades open cluster. So far, no other substellar companions have been unambiguously confirmed via direct imaging around main-sequence stars in Hyades. The star HIP 21152 is an accelerating star as identified by the astrometry from the Ga…
Dynamical Mass of the Young Substellar Companion HD 984 B
Dupuy, Trent J.; Kraus, Adam L.; Tran, Quang H. +5 more
Model-independent masses of substellar companions are critical tools to validate models of planet and brown dwarf cooling, test their input physics, and determine the formation and evolution of these objects. In this work, we measure the dynamical mass and orbit of the young substellar companion HD 984 B. We obtained new high-contrast imaging of t…
Speckle Interferometry at SOAR in 2021
Tokovinin, Andrei; Mason, Brian D.; Mendez, Rene A. +1 more
The speckle interferometry program at the the 4.1 m Southern Astrophysical Research Telescope (SOAR), which started in 2008, now has accumulated over 30,300 individual observations of 12,700 distinct targets. Its main goal is to monitor orbital motion of close binaries, including members of high-order hierarchies and low-mass dwarfs in the solar n…
The Gaia EDR3 view of Johnson-Kron-Cousins standard stars: the curated Landolt and Stetson collections
Rainer, M.; Marinoni, S.; Marrese, P. M. +7 more
Context. In the era of large surveys and space missions, it is necessary to rely on large samples of well-characterized stars for inter-calibrating and comparing measurements from different surveys and catalogues. Among the most employed photometric systems, the Johnson-Kron-Cousins has been used for decades and for a large amount of important dat…
Limits on the mass and initial entropy of 51 Eri b from Gaia EDR3 astrometry
Dupuy, Trent J.; Brandt, Timothy D.; Brandt, G. Mirek
51 Eri b is one of the only young planets consistent with a wide range of possible initial entropy states, including the cold-start scenario associated with some models of planet formation by core accretion. The most direct way to constrain the initial entropy of a planet is by measuring its luminosity and mass at a sufficiently young age that the…
Precise Dynamical Masses of ɛ Indi Ba and Bb: Evidence of Slowed Cooling at the L/T Transition
Dupuy, Trent J.; Brandt, Timothy D.; Li, Yiting +3 more
We report individual dynamical masses of 66.92 ± 0.36 M Jup and 53.25 ± 0.29 M Jup for the binary brown dwarfs ɛ Indi Ba and Bb, measured from long-term (≈10 yr) relative orbit monitoring and absolute astrometry monitoring data on the Very Large Telescope (VLT). Relative astrometry with NACO fully constrains the Keplerian orb…
RR Lyrae-based Distances for 39 Nearby Dwarf Galaxies Calibrated to Gaia eDR3
El-Badry, Kareem; Weisz, Daniel R.; Nagarajan, Pranav
We provide uniform RR Lyrae-based distances to 39 dwarf galaxies in and around the Local Group. We determine distances based on a Bayesian hierarchical model that uses periods and magnitudes of published RR Lyrae in dwarf galaxies and is anchored to well-studied Milky Way (MW) RR Lyrae with spectroscopic metallicities and Gaia eDR3 parallaxes. Gai…
A Mini-Neptune from TESS and CHEOPS Around the 120 Myr Old AB Dor Member HIP 94235
Latham, David W.; Quinn, Samuel N.; Kane, Stephen R. +36 more
The Transiting Exoplanet Survey Satellite (TESS) mission has enabled discoveries of the brightest transiting planet systems around young stars. These systems are the benchmarks for testing theories of planetary evolution. We report the discovery of a mini-Neptune transiting a bright star in the AB Doradus moving group. HIP 94235 (TOI-4399, TIC 464…