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Binarity and beyond in A stars - I. Survey description and first results of VLTI/GRAVITY observations of VAST targets with high Gaia-Hipparcos accelerations
Katz, Boaz; Waisberg, Idel; Klein, Ygal
The connection between the multiplicity of A stars and that of their white dwarf (WD) descendants is not known and the observational mappings of both multiplicities are far from complete. We are conducting an interferometric survey with VLTI/GRAVITY of 20 out of 108 southern A stars within the VAST sample which show large Gaia-Hipparcos proper mot…
Surveying nearby brown dwarfs with HGCA: direct imaging discovery of a faint, high-mass brown dwarf orbiting HD 176535 A
Jensen-Clem, Rebecca; Currie, Thayne; Lewis, Briley L. +17 more
Brown dwarfs with well-measured masses, ages, and luminosities provide direct benchmark tests of substellar formation and evolutionary models. We report the first results from a direct imaging survey aiming to find and characterize substellar companions to nearby accelerating stars with the assistance of the Hipparcos-Gaia Catalog of Accelerations…
Dynamical masses and ages of Sirius-like systems
Kiman, Rocio; Brandt, Timothy D.; Li, Yiting +4 more
We measure precise orbits and dynamical masses and derive age constraints for six confirmed and one candidate Sirius-like systems, including the Hyades member HD 27483. Our orbital analysis incorporates radial velocities, relative astrometry, and Hipparcos-Gaia astrometric accelerations. We constrain the main-sequence lifetime of a white dwarf's p…
New evidence about HW Vir's circumbinary planets from Hipparcos-Gaia astrometry and a reanalysis of the eclipse timing variations using nested sampling
Triaud, Amaury H. M. J.; Kervella, Pierre; Baycroft, Thomas A.
The post common-envelope eclipsing binary HW Virginis (HW Vir) has had many circumbinary companions proposed based on eclipse timing variations. Each proposed solution has lacked in predictability and orbital stability, leaving the origin of the eclipse timing variations an active area of research. Leveraging the catalogue of Hipparcos and Gaia pr…
Binarity and beyond in A stars II. Disentangling the four stars in the vicinity of the triple HIP 87813 within the quintuple system HJ2814
Katz, Boaz; Waisberg, Idel; Klein, Ygal
A-type stars are the progenitors of about half of the white dwarfs (WDs) that currently exist. The observational mappings of both multiplicities are far from complete and their connection is not known. We are in the process of obtaining tight constraints on a sample of 108 southern and nearby A-stars that are part of the VAST sample by conducting …
Identifying and characterizing ultracool dwarfs ejected from post-encounter disintegrating systems
Carballo-Bello, Julio A.; Gromadzki, Mariusz; Marocco, Federico +3 more
Disintegrating multiple systems have been previously discovered from kinematic studies of the Hipparcos catalogue. They are presumably the result of dynamical encounters taking place in the Galactic disc between single/multiple systems. In this paper, we aim to expand the search for such systems, to study their properties, as well as to characteri…
HIP 67506 C: MagAO-X confirmation of a new low-mass stellar companion to HIP 67506 A
Weinberger, Alycia J.; Guyon, Olivier; Close, Laird M. +17 more
We report the confirmation of HIP 67506 C, a new stellar companion to HIP 67506 A. We previously reported a candidate signal at 2λ/D (240 mas) in L' in MagAO/Clio imaging using the binary differential imaging technique. Several additional indirect signals showed that the candidate signal merited follow-up: significant astrometric accele…