HATS-8b: A low-density transiting super-Neptune

Bayliss, D. and Hartman, J. D. and Bakos, G. A. and Penev, K. and Zhou, G. ORCID: https://orcid.org/0000-0002-4891-3517 and Brahm, R. and Rabus, M. and Jordan, A. and Mancini, L. and de Val-Borro, M. and Bhatti, W. and Espinoza, N. and Csubry, Z. and Howard, A. W. and Fulton, B. J. and Buchhave, L. A. and Henning, T. and Schmidt, B. and Ciceri, S. and Noyes, R. W. and Isaacson, H. and Marcy, G. W. and Suc, V. and Lazar, J. and Papp, I. and Sari, P. (2015) HATS-8b: A low-density transiting super-Neptune. The Astronomical Journal, 150 (2):49. pp. 1-9. ISSN 0004-6256

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HATS-8b is a low density transiting super-Neptune discovered as part of the HATSouth project. The planet orbits its solar-like G-dwarf host (V = 14.03 +/- 0.10, T-eff = 5679 +/- 50 K) with a period of 3.5839 days. HATS-8b is the third lowest-mass transiting exoplanet to be discovered from a wide-field ground-based search, and with a mass of 0.138 +/- 0.019 M-J it is approximately halfway between the masses of Neptune and Saturn. However, HATS-8b has a radius of 0.873(-0.075)(+0.123) R-J, resulting in a bulk density of just 0.259 +/- 0.091 g cm(-3). The metallicity of the host star is super-solar ([Fe/H] = 0.210 +/- 0.080), providing evidence against the idea that low-density exoplanets form from metal-poor environments. The low density and large radius of HATS-8b results in an atmospheric scale height of almost 1000 km, and in addition to this there is an excellent reference star of nearly equal magnitude at just 19' separation in the sky. These factors make HATS-8b an exciting target for future atmospheric characterization studies, particularly for long-slit transmission spectroscopy.

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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: 30 Jan 2022 23:35
Last Modified: 30 Jan 2022 23:35
Uncontrolled Keywords: planetary systems; stars: individual: HATS-8; techniques:; photometric; techniques: spectroscopic; 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/10.1088/0004-6256/150/2/49
URI: http://eprints.usq.edu.au/id/eprint/44964

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