A Pre-Gaia Census of Nearby Stellar Groups

TL;DR

This paper reviews the status of nearby young stellar groups within 100 parsecs, assessing their usefulness for studying stellar evolution, exoplanets, and brown dwarfs, and discusses their ages and potential supernova influences.

Contribution

Provides a comprehensive assessment and grading of known and poorly characterized nearby stellar groups for age-dating and evolutionary studies.

Findings

Grades for stellar groups established for 2015.

Discussion of potential supernova impact from Tuc-Hor.

Identification of poorly characterized and non-group stellar populations.

Abstract

The nearest, youngest groups of stars to the Sun provide important samples of age-dated stars for studying circumstellar disk evolution, imaged exoplanets, and brown dwarfs. I briefly comment on the status of the known stellar groups within 100 pc: $\beta$ Pic, AB Dor, UMa, Car-Near, Tuc-Hor and $\beta$ Tuc nucleus, Hyades, Col, TW Hya, Car, Coma Ber, 32 Ori, $\eta$ Cha, and $\chi^1$ For. I also discuss some poorly characterized groups and "non-groups." Grades for 2015 of Pass, Satisfactory, or Fail are assigned to the groups for the purposes of age-dating stars and brown dwarfs. I speculate that Tuc-Hor could have provided a supernova ~60 pc away ~2.2 Myr ago which showered the Earth with traces of 60Fe-bearing dust.