Pleiades or Not? Resolving the Status of the Lithium-rich M Dwarfs HHJ 339 and HHJ 430

Journal Article · Wed Jul 01 04:00:00 EDT 2020 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/AB93C9· OSTI ID:23013266

Stauffer, John ^[1]; Barrado, David ^[2]; David, Trevor ^[3]; Rebull, Luisa M. ^[4]; Hillenbrand, Lynne A. ^[5]; Mamajek, Eric E. ^[6]; Oppenheimer, Rebecca ^[7]; Aigrain, Suzanne ^[8]; Bouy, Herve ^[9]; Lillo-Box, Jorge ^[10]

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1. Spitzer Science Center (SSC), IPAC, California Institute of Technology, Pasadena, CA 91125 (United States)
2. Centro de Astrobiología, Dpto. de Astrofísica, INTA-CSIC, E-28692, ESAC Campus, Villanueva de la Cañada, Madrid (Spain)
3. Center for Computational Astrophysics, Flatiron Institute, New York, NY 10010 (United States)
4. Infrared Science Archive (IRSA), IPAC, California Institute of Technology, 1200 E. California Boulevard, MS 100-22, Pasadena, CA 91125 (United States)
5. Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States)
6. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)
7. American Museum of Natural History, New York, NY 12345 (United States)
8. Sub-department of Astrophysics, Department of Physics, University of Oxford, Oxford, OX1 3RH (United Kingdom)
9. Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, Allée Geoffroy Saint-Hillaire, F-33615 Pessac (France)
10. Depto. de Astrofísica, Centro de Astrobiología (CSIC-INTA), ESAC campus E-28692 Villanueva de la Canada (Madrid) (Spain)

Oppenheimer et al. discovered two M5 dwarfs in the Pleiades with nearly primordial lithium. These stars are not low enough in mass to represent the leading edge of the lithium depletion boundary at Pleiades age (∼125 Myr). A possible explanation for the enhanced lithium in these stars is that they are actually not members of the Pleiades but instead are members of a younger moving group seen in projection toward the Pleiades. We have used data from Gaia DR2 to confirm that these two stars, HHJ 339 and HHJ 430, are indeed not members of the Pleiades. Based on their space motions, parallaxes, and positions in a Gaia-based color–magnitude diagram, it is probable that these two stars are about 40 parsecs foreground to the Pleiades and have ages of ∼25 Myr. Kinematically they are best matched to the 32 Ori moving group.

• OSTI ID: 23013266
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 1 Vol. 160; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COLOR
DIAGRAMS
DWARF STARS
LITHIUM
MASS
SPACE