A kinematically hot population of young stars in the solar neighbourhood

Binks, AS; Wright, Nicholas; Jeffries, Robin

Abstract

In the last three decades several hundred nearby members of young stellar moving groups (MGs) have been identified, but there has been less systematic effort to quantify or characterise young stars that do not belong to previously identified MGs. Using a kinematically unbiased sample of 225 lithium-rich stars within 100 pc, we find that only $50 \pm 10$ per cent of young ($\lesssim 125$ Myr), low-mass ($0.5<M/M_{\odot}<1.0$) stars, are kinematically associated with known MGs. Whilst we find some evidence that six of the non-MG stars may be connected with the Lower Centaurus-Crux association, the rest form a kinematically "hotter" population, much more broadly dispersed in velocity, and with no obvious concentrations in space. The mass distributions of the MG members and non-MG stars is similar, but the non-MG stars may be older on average. We briefly discuss several explanations for the origin of the non-MG population.

Citation

Binks, A., Wright, N., & Jeffries, R. (2020). A kinematically hot population of young stars in the solar neighbourhood. Monthly Notices of the Royal Astronomical Society, 494(2), 2429-2439. https://doi.org/10.1093/mnras/staa909

• Journal Article Type: Article
• Acceptance Date: Mar 28, 2020
• Online Publication Date: Apr 7, 2020
• Publication Date: 2020-05
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 494
• Issue: 2
• Pages: 2429-2439
• DOI: https://doi.org/10.1093/mnras/staa909
• Keywords: stars: kinematics and dynamics, stars: late-type, stars: pre-main-sequence, solar neighbourhood
• Publisher URL: https://doi.org/10.1093/mnras/staa909