Unresolved stellar companions with Gaia DR2 astrometry

  title={Unresolved stellar companions with Gaia DR2 astrometry},
  author={Vasily Belokurov and Zephyr Penoyre and Semyeong Oh and Giuliano Iorio and Simon T. Hodgkin and N. W. Evans and Andrew Everall and Sergey E. Koposov and Christopher A. Tout and Robert G Izzard and Cathie J. Clarke and Anthony G. A. Brown},
  journal={arXiv: Solar and Stellar Astrophysics},
  • Vasily Belokurov, Zephyr Penoyre, +9 authors Anthony G. A. Brown
  • Published 2020
  • Physics
  • arXiv: Solar and Stellar Astrophysics
  • 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 detected with the reduced chi2 statistic, or RUWE, provided as part of Gaia DR2. We convert RUWE into the amplitude of the image centroid wobble, which, if scaled by the source distance, is proportional to the physical separation between companions (for periods up to several years). We test this idea on… CONTINUE READING


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