HATS-70b: A 13 MJ Brown Dwarf Transiting an A Star

Zhou, G. ORCID: https://orcid.org/0000-0002-4891-3517 and Bakos, G. A. and Bayliss, D. and Bento, J. and Bhatti, W. and Brahm, R. and Csubry, Z. and Espinoza, N. and Hartman, J. D. and Henning, T. and Jordan, A. and Mancini, L. and Penev, K. and Rabus, M. and Sarkis, P. and Suc, V. and de Val-Borro, M. and Rodriguez, J. E. and Osip, D. and Kedziora-Chudczer, L. and Bailey, J. and Tinney, C. G. and Durkan, S. and Lazar, J. and Papp, I. and Sari, P. (2019) HATS-70b: A 13 MJ Brown Dwarf Transiting an A Star. The Astronomical Journal, 157 (1):31. pp. 1-14. ISSN 0004-6256

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Abstract

We report the discovery of HATS-70b, a transiting brown dwarf at the deuterium burning limit. HATS-70b has a mass of Mp = 12.9+1.8-1.6 MJup and a radius of Rp 1.384+ 0.074 0.079 MJup, residing in a close-in orbit with a period of 1.89 days. The host star is a M∗= M 1.78 0.12 M A star rotating at = v sin I 40.61+ km s- 0.35 0.32 1, enabling us to characterize the spectroscopic transit of the brown dwarf via Doppler tomography. We find that HATS-70b, like other massive planets and brown dwarfs previously sampled, orbits in a low projected-obliquity orbit with l = 8.9+4.5 5.6. The low obliquities of these systems is surprising given all brown dwarf and massive planets with obliquities measured orbit stars hotter than the Kraft break. This trend is tentatively inconsistent with dynamically chaotic migration for systems with massive companions, though the stronger tidal influence of these companions makes it difficult to draw conclusions on the primordial obliquity distribution of this population. We also introduce a modeling scheme for planets around rapidly rotating stars, accounting for the influence of gravity darkening on the derived stellar and planetary parameters.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 09 Feb 2022 02:47
Last Modified: 14 Feb 2022 01:07
Uncontrolled Keywords: stars: individual (HATS-70); techniques: spectroscopic; techniques: photometric; Astrophysics - Earth and Planetary Astrophysics
Fields of Research (2008): 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Fields of Research (2020): 51 PHYSICAL SCIENCES > 5101 Astronomical sciences > 510109 Stellar astronomy and planetary systems
Socio-Economic Objectives (2008): E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Socio-Economic Objectives (2020): 28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280120 Expanding knowledge in the physical sciences
Identification Number or DOI: https://doi.org/10.3847/1538-3881/aaf1bb
URI: http://eprints.usq.edu.au/id/eprint/45040

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