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arXiv · 1605.07927

Population Properties of Brown Dwarf Analogs to Exoplanets

Jacqueline K. Faherty·Adric R. Riedel·Kelle L. Cruz·Jonathan Gagne·Joseph C. Filippazzo·Erini Lambrides·Haley Fica·Alycia Weinberger·John R. Thorstensen·C. G. Tinney·Vivienne Baldassare·Emily Lemonier·Emily L. Rice
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Abstract

We present a kinematic analysis of 152 low surface gravity M7-L8 dwarfs by adding 8 parallaxes, 38 radial velocities, and 19 proper motions. We find 39 objects to be high-likelihood or bona fide members of nearby moving groups, 92 objects to be ambiguous members and 21 objects that are non-members. We find that gravity classification and photometric color separate 5-150 Myr sources from > 3 Gyr field objects, but they do not correlate one-to-one with the narrower 5 -150 Myr age range. The absolute magnitudes of low-gravity sources from J band through W3 show a flux redistribution when compared to equivalent field sources that is correlated with spectral subtype. Clouds, which are a far more dominant opacity source for L dwarfs, are the likely cause. On CMDs, the latest-type low-gravity L dwarfs drive the elbow of the L/T transition up to 1 mag redder and 1 mag fainter than field dwarfs at M_J but are consistent with or brighter than the elbow at M_W1 and M_W2. Furthermore, there is an indication on CMD's (such as M_J versus (J-W2) of increasingly redder sequences separated by gravity classification. Examining bolometric luminosities for planets and low-gravity objects, we confirm that young M dwarfs are overluminous while young L dwarfs are normal compared to the field. This translates into warmer M dwarf temperatures compared to the field sequence while lower temperatures for L dwarfs.

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Jacqueline K. Faherty, Adric R. Riedel, Kelle L. Cruz, Jonathan Gagne, Joseph C. Filippazzo, Erini Lambrides, Haley Fica, Alycia Weinberger, John R. Thorstensen, C. G. Tinney, Vivienne Baldassare, Emily Lemonier, Emily L. Rice. 2016-05-25. Population Properties of Brown Dwarf Analogs to Exoplanets. https://doi.org/10.3847/0067-0049%2F225%2F1%2F10

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