English

Nearby quintuple systems Kappa Tucanae and Xi Scorpii

Solar and Stellar Astrophysics 2021-01-11 v2

Abstract

Architecture and parameters of two wide nearby hierarchical systems containing five solar-type stars each, κ\kappa Tuc and ξ\xi Sco, are studied. Using Gaia astrometry and photometry, masses are determined from visual orbits and isochrones, effective temperatures from spectra or colors. Both systems are ~2 Gyr old. Their spatial motion corresponds to young disk but does not match any known kinematic group. Internal proper motions relative to the center of mass and radial velocities show that wide ~8 kau outer pairs are bound. No correlation between orbit orientations in the inner subsystems is observed. All masses except one are confined to the narrow range from 0.8 to 1.5 solar. Strongly correlated masses and wide orbits can be explained if those systems formed by fragmentation in relative isolation and their components accreted gas from common source, as expected in a hierarchical collapse. Young moving groups could be formed in similar environments, and many of them contain high-order hierarchies.

Keywords

Cite

@article{arxiv.2005.04057,
  title  = {Nearby quintuple systems Kappa Tucanae and Xi Scorpii},
  author = {Andrei Tokovinin},
  journal= {arXiv preprint arXiv:2005.04057},
  year   = {2021}
}

Comments

Accepted by The Astronomical Journal; 9 pages, 8 figures, 5 tables