4567512
doi
10.5281/zenodo.4567512
oai:zenodo.org:4567512
user-coolstars20half
Burgasser, Adam
University of California San Diego
Theissen, Christopher
University of California San Diego
Gelino, Christopher
Infrared Processing and Analysis Center, Caltech
Birky, Jessica
University of Washington
Diamant, Sharon
Leiden University
Aganze, Christian
University of California San Diego
Blake, Cullen
University of Pennsylvania
Radial Velocities and Kinematic Ages of Nearby T Dwarfs from Keck/NIRSPEC High-Resolution Spectroscopy
Hsu, Chih-Chun
University of California San Diego
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
Very low mass stars
<p>Precise measurements of radial (RV) and rotational (vsini) velocities of stars are essential for studying stellar kinematics (space velocities and dispersions), binary orbits (mass measurements and formation), and rotational dynamics (angular momentum evolution). The high-resolution spectroscopic observations necessary to make these measurements are challenging for the intrinsically faint and low-temperature ultracool dwarfs (UCDs), stellar and sub-stellar objects with masses below 0.1 M<sub>Sun</sub>. Previous local UCD kinematic studies indicated conflicting L dwarf kinematic ages, with little constraints on the T dwarf kinematic due to the small sample size. We present a radial and rotational velocity survey of 37 nearby (d ≤ 20 pc) T dwarfs based on forward-modeling analysis of nearly twenty years of high-resolution spectra obtained with Keck/NIRSPEC. We present the distributions of our RV and vsini measurements, and statistically analyze kinematic ages of the local ultracool dwarf population-based on RV and astrometric measurements of 173 late-M, L, and T dwarfs within 20 pc, and show that the L dwarfs as a population are significantly more dispersed and hence older than expected from population simulations. However, the local L dwarf sample has a higher fraction of thick disk sources, and removing them brings the L dwarf age into alignment, resolving a decade-old mystery. A kinematic dispersion break is found around the L4–L6 subtypes, which likely reflects the terminus of the stellar Main Sequence.</p>
Zenodo
2021-02-26
info:eu-repo/semantics/conferencePoster
4567511
user-coolstars20half
1614385635.939008
3144656
md5:8ad13ed907ea9a91cfe2d61380fdc2ad
https://zenodo.org/records/4567512/files/2021coolstars20half_CHsu.pdf
public
10.5281/zenodo.4567511
isVersionOf
doi