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arXiv · 2306.08450

Investigating Possible Binarity for GJ 229B

Alex R. Howe·Avi M. Mandell·Michael W. McElwain
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Abstract

GJ 229B, the first type-T brown dwarf to be discovered, has presented a tension between comparisons with evolutionary models and the larger-than-expected mass and radius values derived from spectroscopic and astrometric observations. We examine the hypothesis that GJ 229B is actually a binary sub-stellar object by using two grid-based fits using evolutionary models to explore the range of mass ratios of the possible binary components. We find that the best-fit component values are most consistent with a roughly 2:1 binary mass ratio and an age range of 2-6 Gyr. The observed temperatures, masses, and apparent radii match expected values from evolutionary models for a binary much better than a single-object model, but more detailed observations and modeling are needed to definitively confirm the binary hypothesis.

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Alex R. Howe, Avi M. Mandell, Michael W. McElwain. 2023-06-14. Investigating Possible Binarity for GJ 229B. https://doi.org/10.3847/2041-8213%2Facdd76

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