Stellar Companion Astrometry

Identifying Dynamical Masses of Long Period Companions Using Orbit Fitting code with HGCA Astrometry

Background

The Hipparcos-Gaia Catalog of Accelerations contains a subset of stars that appeared to be accelerating during a cross calibration between the High Precision PARallax Collecting Satellite (HIPPARCOS) catalog and Gaia. ( Brandt 2021)

A proposed cause of these accelerations is the presence of a previously unknown stellar companion. We aimed to constrain the masses of these companions using sophisticated orbit fitting codes.

orvara

Orbits from Radial Velocity, Absolute and/or Relative Astrometry (orvara) measures precise masses and other orbital parameters from the HGCA catalog ( Brandt et al. 2021). Using the NASA Keck HIRES RV curves, we focused on companions within 10 - 100 Jupiter masses within 20 parsecs and were able to fit the orbit of 15 Sge b.

Results