Stellar and substellar companions of nearby stars from Gaia DR2

  title={Stellar and substellar companions of nearby stars from Gaia DR2},
  author={Pierre Kervella and Fr{\'e}d{\'e}ric Arenou and Franccois Mignard and Fr'ed'eric Th'evenin},
  journal={Astronomy \& Astrophysics},
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 high precision astrometry. Aims. We aim to characterize the presence of physical companions of stellar and substellar mass in orbit around nearby stars… 
High-speed stars: Galactic hitchhikers
Context. The search for stars born in the very early stages of the Milky Way star formation history is of paramount importance in the study of the early Universe since their chemistry carries
Detection of a Low-mass Stellar Companion to the Accelerating A2IV Star HR 1645
The ∼500 Myr A2IV star HR 1645 has one of the most significant low-amplitude accelerations of nearby early-type stars measured from a comparison of the Hipparcos and Gaia astrometric catalogs. This
Unresolved stellar companions with Gaia DR2 astrometry
For stars with unresolved companions, motions of the centre of light and that of mass decouple, causing a single-source astrometric model to perform poorly. We show that such stars can be easily
Stellar clustering shapes the architecture of planetary systems
Old, co-moving stellar groups around exoplanet host stars in the astrometric data from the Gaia satellite are identified and it is demonstrated that the architecture of planetary systems exhibits a strong dependence on local stellar clustering in position-velocity phase space.
A Dearth of Close-in Stellar Companions to M-dwarf TESS Objects of Interest
TESS has proven to be a powerful resource for finding planets, including those that orbit the most prevalent stars in our galaxy: M dwarfs. Identification of stellar companions (both bound and
The Possible Astrometric Signature of a Planetary-mass Companion to the Nearby Young Star TW Piscis Austrini (Fomalhaut B): Constraints from Astrometry, Radial Velocities, and Direct Imaging
We present constraints on the presence of substellar companions to the nearby (d ∼ 7.6 pc) young (440 ± 40 Myr) K4Ve star TW Piscis Austrini, the wide (∼0.3 pc) companion to the A4V star Fomalhaut.
Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2
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
A surprise in the updated list of stellar perturbers of long-period comet motion
Context. The second Gaia data release (Gaia DR2) provided us with the precise five-parameter astrometry for 1.3 billion of sources. As stars passing close to the Solar System are thought to influence
Resolving the Multiplicity of Exoplanet Host Stars in Gemini/NIRI Data
The majority of stars have one or more stellar companions. As exoplanets continue to be discovered, it is crucial to examine planetary systems to identify their stellar companions. By observing a
Commotion in their Motions: Proper Motion Anomalies of Nearby AGB Stars
Proper motion anomalies (PMa) are often useful for identifying companions, but using this technique for large and luminous stars like Asymptotic Giant Branch (AGB) stars is problematic. We studied


The SOPHIE search for northern extrasolar planets - IX. Populating the brown dwarf desert
Radial velocity planet search surveys of nearby solar-type stars have shown a strong scarcity of brown dwarf companions within similar to 5 AU. There is presently no comprehensive explanation for
Stellar activity and rotation frustrate the detection of exoplanets through the radial velocity technique. This effect is particularly of concern for M dwarfs, which can remain magnetically active
Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2
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
Toward detection of terrestrial planets in the habitable zone of our closest neighbor: proxima Centauri
Context. The precision of radial velocity (RV) measurements to detect indirectly planetary companions of nearby stars has improved to enable the discovery of extrasolar planets in the Neptune and
Astrometric measurements are presented for seven nearby stars with previously detected planets: six M dwarfs (GJ 317, GJ 667C, GJ 581, GJ 849, GJ 876, and GJ 1214) and one K dwarf (BD-10 -3166).
A candidate super-Earth planet orbiting near the snow line of Barnard’s star
Analysis of 20 years of observations of Barnard’s star from seven facilities reveals a signal with a period of 233 days that is indicative of a companion planet, and a long-term modulation that could arise from a stellar magnetic-activity cycle or from a more distant planetary object is revealed.
Precise Dynamical Masses of Directly Imaged Companions from Relative Astrometry, Radial Velocities, and Hipparcos–Gaia DR2 Accelerations
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,
Two planets around Kapteyn's star: a cold and a temperate super-Earth orbiting the nearest halo red dwarf
Exoplanets of a few Earth masses can be now detected around nearby low-mass stars using Doppler spectroscopy. In this paper, we investigate the radial velocity variations of Kapteyn's star, which is
The Geneva–Copenhagen Survey of the Solar Neighbourhood
Abstract We report on a new survey of metallicities, ages, and Galactic orbits for a complete, magnitude-limited, and kinematically unbiased all-sky sample of 16 682 nearby F- and G-dwarfs. Our ∼ 63
Constraints on the substellar companions in wide orbits around the Barnard's Star from CanariCam mid-infrared imaging
We have performed mid-infrared imaging of Barnard's Star, one of the nearest stars to the Sun, using CanariCam on the 10.4 m Gran Telescopio Canarias. We aim to investigate an area within 1-10 arcsec