Planets Around Low-Mass Stars (PALMS). V. Age-Dating Low-Mass Companions to Members and Interlopers of Young Moving Groups
| Autor: | Benjamin T. Montet, Michael C. Kotson, Christoph Baranec, Brendan P. Bowler, John Asher Johnson, Zahed Wahhaj, Beth Biller, Evgenya L. Shkolnik, Katelyn N. Allers, Alycia J. Weinberger, Eric L. Nielsen, Nicholas M. Law, Kimberly M. Aller, Gregory J. Herczeg, William M. J. Best, Reed Riddle, Michael C. Liu, Andrew W. Howard, Andrew W. Mann, Laura Flagg, Trent J. Dupuy, Joshua E. Schlieder, Thomas L. Hayward, Sasha Hinkley, Justin R. Crepp |
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| Rok vydání: | 2015 |
| Předmět: |
Physics
Earth and Planetary Astrophysics (astro-ph.EP) Proper motion Brown dwarf FOS: Physical sciences Astronomy and Astrophysics Astrophysics Exoplanet Radial velocity Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science Binary star Pleiades Stellar evolution Solar and Stellar Astrophysics (astro-ph.SR) Astrophysics - Earth and Planetary Astrophysics |
| DOI: | 10.48550/arxiv.1505.01494 |
| Popis: | We present optical and near-infrared adaptive optics (AO) imaging and spectroscopy of 13 ultracool (>M6) companions to late-type stars (K7-M4.5), most of which have recently been identified as candidate members of nearby young moving groups (YMGs; 8-120 Myr) in the literature. The inferred masses of the companions (~10-100 Mjup) are highly sensitive to the ages of the primary stars so we critically examine the kinematic and spectroscopic properties of each system to distinguish bona fide YMG members from old field interlopers. 2MASS J02155892-0929121 C is a new M7 substellar companion (40-60 Mjup) with clear spectroscopic signs of low gravity and hence youth. The primary, possibly a member of the ~40 Myr Tuc-Hor moving group, is visually resolved into three components, making it a young low-mass quadruple system in a compact (1 Gyr) tidally-locked spectroscopic binaries without convincing kinematic associations with any known moving group. The high rate of false positives in the form of old active stars with YMG-like kinematics underscores the importance of radial velocity and parallax measurements to validate candidate young stars identified via proper motion and activity selection alone. Finally, we spectroscopically confirm the cool temperature and substellar nature of HD 23514 B, a recently discovered M8 benchmark brown dwarf orbiting the dustiest-known member of the Pleiades. [Abridged] Accepted to ApJ |
| Databáze: | OpenAIRE |
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