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arXiv · 2403.12311

BD-14 3065b (TOI-4987b): from giant planet to brown dwarf: evidence for deuterium burning in old age?

Ján Šubjak·David W. Latham·Samuel N. Quinn·Perry Berlind·Michael L. Calkins·Gilbert A. Esquerdo·Rafael Brahm·Eike Guenther·Jan Janík·Petr Kabáth·Leonardo Vanzi·José A. Caballero·Jon M. Jenkins·Ismael Mireles·Sara Seager·Avi Shporer·Stephanie Striegel·Joshua N. Winn
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Abstract

The present study reports the confirmation of BD-14 3065b, a transiting planet/brown dwarf in a triple-star system, with a mass near the deuterium burning boundary. BD-14 3065b has the largest radius observed within the sample of giant planets and brown dwarfs around post-main-sequence stars. Its orbital period is 4.3 days, and it transits a subgiant F-type star with a mass of $M_\star=1.41 \pm 0.05 M_{\odot}$, a radius of $R_\star=2.35 \pm 0.08 R_{\odot}$, an effective temperature of $T_{\rm eff}=6935\pm90$ K, and a metallicity of $-0.34\pm0.05$ dex. By combining TESS photometry with high-resolution spectra acquired with the TRES and Pucheros+ spectrographs, we measured a mass of $M_p=12.37\pm0.92 M_J$ and a radius of $R_p=1.926\pm0.094 R_J$. Our discussion of potential processes that could be responsible for the inflated radius led us to conclude that deuterium burning is a plausible explanation resulting from the heating of BD-14 3065b's interior. Detection of the secondary eclipse with TESS photometry enables a precise determination of the eccentricity $e_p=0.066\pm0.011$ and reveals BD-14 3065b has a brightness temperature of $3520 \pm 130$ K. With its unique characteristics, BD-14 3065b presents an excellent opportunity to study its atmosphere through thermal emission spectroscopy.

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Ján Šubjak, David W. Latham, Samuel N. Quinn, Perry Berlind, Michael L. Calkins, Gilbert A. Esquerdo, Rafael Brahm, Eike Guenther, Jan Janík, Petr Kabáth, Leonardo Vanzi, José A. Caballero, Jon M. Jenkins, Ismael Mireles, Sara Seager, Avi Shporer, Stephanie Striegel, Joshua N. Winn. 2024-06-03. BD-14 3065b (TOI-4987b): from giant planet to brown dwarf: evidence for deuterium burning in old age?. https://doi.org/10.1051/0004-6361%2F202349028

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