Search Publications
Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly
Mignard, François; Thévenin, Frédéric; Kervella, Pierre +1 more
Context. The census of stellar and substellar companions of nearby stars is largely incomplete, in particular toward the low-mass brown dwarf and long-period exoplanets. It is, however, fundamentally important in the understanding of the stellar and planetary formation and evolution mechanisms. Nearby stars are particularly favorable targets for h…
Precise Dynamical Masses of Directly Imaged Companions from Relative Astrometry, Radial Velocities, and Hipparcos-Gaia DR2 Accelerations
Dupuy, Trent J.; Bowler, Brendan P.; Brandt, Timothy D.
We measure dynamical masses for five objects—three ultracool dwarfs, one low-mass star, and one white dwarf—by fitting orbits to a combination of the Hipparcos-Gaia Catalog of Accelerations, literature radial velocities, and relative astrometry. Our approach provides precise masses without any assumptions about the primary star, even though the ob…
Abundance to age ratios in the HARPS-GTO sample with Gaia DR2. Chemical clocks for a range of [Fe/H]
Chaplin, W. J.; Moya, A.; Davies, G. R. +8 more
Aims: The purpose of this work is to evaluate how several elements produced by different nucleosynthesis processes behave with stellar age and provide empirical relations to derive stellar ages from chemical abundances.
Methods: We derived different sets of ages using Padova and Yonsei-Yale isochrones and HIPPARCOS and Gaia parallaxes fo…
Gaia Data Release 2. Cross-match with external catalogues: algorithms and results
Marinoni, S.; Marrese, P. M.; Altavilla, G. +1 more
Context. Although the Gaia catalogue on its own is a very powerful tool, it is the combination of this high-accuracy archive with other archives that will truly open up amazing possibilities for astronomical research. The advanced interoperation of archives is based on cross-matching, leaving the user with the feeling of working with one single da…
Stellar population of Sco OB2 revealed by Gaia DR2 data
Micela, G.; Sciortino, S.; Pillitteri, I. +2 more
Context. The Sco OB2 association is the nearest OB association, extending over approximately 2000 square degrees on the sky. Only its brightest and most massive members are already known (from HIPPARCOS) across its entire size, while studies of its lower mass population refer only to small portions of its extent.
Aims: In this work we exploit…
The Asteroseismic Target List for Solar-like Oscillators Observed in 2 minute Cadence with the Transiting Exoplanet Survey Satellite
Chaplin, William J.; Davies, Guy R.; Latham, David W. +21 more
We present the target list of solar-type stars to be observed in short-cadence (2 minute) for asteroseismology by the NASA Transiting Exoplanet Survey Satellite (TESS) during its 2 year nominal survey mission. The solar-like Asteroseismic Target List (ATL) is comprised of bright, cool main-sequence and subgiant stars and forms part of the larger t…
A Model-independent Mass and Moderate Eccentricity for β Pic b
Kratter, Kaitlin M.; Dupuy, Trent J.; Bowler, Brendan P. +1 more
We use a cross-calibration of Hipparcos and Gaia second data release astrometry for β Pic to measure the mass of the giant planet β Pic b (13 ± 3 {M}Jup}) in a comprehensive joint orbit analysis that includes published relative astrometry and radial velocities. Our mass uncertainty is somewhat higher than previous work because our astro…
Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2. I. Binarity from proper motion anomaly
Mérand, Antoine; Gieren, Wolfgang; Gallenne, Alexandre +8 more
Context. Classical Cepheids (CCs) and RR Lyrae stars (RRLs) are important classes of variable stars used as standard candles to estimate galactic and extragalactic distances. Their multiplicity is imperfectly known, particularly for RRLs. Astoundingly, to date only one RRL has convincingly been demonstrated to be a binary, TU UMa, out of tens of t…
A volume-limited survey of mCP stars within 100 pc - I. Fundamental parameters and chemical abundances
Wade, G. A.; Neiner, C.; Sikora, J. +1 more
We present the first results of a volume-limited survey of main-sequence (MS) magnetic chemically peculiar (mCP) stars. The sample consists of all identified intermediate-mass MS stars (mCP and non-mCP) within a heliocentric distance of 100 pc as determined using Hipparcos parallaxes. The two populations are compared in order to determine the uniq…
Barium and related stars, and their white-dwarf companions. II. Main-sequence and subgiant starss
Jorissen, A.; Pourbaix, D.; Escorza, A. +12 more
Barium (Ba) dwarfs and CH subgiants are the less evolved analogues of Ba and CH giants. They are F- to G-type main-sequence stars polluted with heavy elements by their binary companions when the companion was on the asymptotic giant branch (AGB). This companion is now a white dwarf that in most cases cannot be directly detected. We present a large…