Exoplanets & Exomoons

TOI-908: A Planet At The Edge Of The Neptune Desert Transiting A G-type Star

By Keith Cowing
Status Report
June 19, 2023
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TOI-908: A Planet At The Edge Of The Neptune Desert Transiting A G-type Star
Target Pixel File (TPF) from TESS sector 1 with TOI-908 marked with a white cross. Other sources from Gaia DR2 are marked with red circles sized by scaled magnitudes relative to the target, ranked by distance. The aperture mask is indicated by the red outline. — astro-ph.EP

We present the discovery of an exoplanet transiting TOI-908 (TIC-350153977) using data from TESS sectors 1, 12, 13, 27, 28 and 39. TOI-908 is a T = 10.7 mag G-dwarf (Teff = 5626 ± 61 K) solar-like star with a mass of 0.950 ± 0.010 M⊙ and a radius of 1.028 ± 0.030 R⊙.

The planet, TOI-908 b, is a 3.18 ± 0.16 R⊕ planet in a 3.18 day orbit. Radial velocity measurements from HARPS reveal TOI-908 b has a mass of approximately 16.1 ± 4.1 M⊕ , resulting in a bulk planetary density of 2.7+0.2-0.4 g cm-3. TOI-908 b lies in a sparsely-populated region of parameter space known as the Neptune desert. The planet likely began its life as a sub-Saturn planet before it experienced significant photoevaporation due to X-rays and extreme ultraviolet radiation from its host star, and is likely to continue evaporating, losing a significant fraction of its residual envelope mass.

Faith Hawthorn, Daniel Bayliss, David J. Armstrong, Jorge Fernández Fernández, Ares Osborn, Sérgio G. Sousa, Vardan Adibekyan, Jeanne Davoult, Karen A. Collins, Yann Alibert, Susana C. C. Barros, François Bouchy, Matteo Brogi, David R. Ciardi, Tansu Daylan, Elisa Delgado Mena, Olivier D. S. Demangeon, Rodrigo F. Díaz, Tianjun Gan, Keith Horne, Sergio Hoyer, Alan M. Levine, Jorge Lillo-Box, Louise D. Nielsen, Hugh P. Osborn, George R. Ricker, José Rodrigues, Nuno C. Santos, Richard P. Schwarz, Sara Seager, Juan Serrano Bell, Avi Shporer, Chris Stockdale, Paul A. Strøm, Peter Tenenbaum, Stéphane Udry, Peter J. Wheatley, Joshua N. Winn, Carl Ziegler

Comments: 17 pages, 17 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2306.09758 [astro-ph.EP] (or arXiv:2306.09758v1 [astro-ph.EP] for this version)
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Submission history
From: Faith Hawthorn
[v1] Fri, 16 Jun 2023 10:42:34 UTC (10,053 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻