TOI-908: a planet at the edge of the Neptune desert transiting a G-type star

Hawthorn, F.; Bayliss, D.; Armstrong, D. J.; Fernandez Fernandez, J.; Osborn, A.; Sousa, S. G.; Adibekyan, V.; Davoult, J.; Collins, K. A.; Alibert, Y.; Barros, S. C. C.; Bouchy, F.; Brogi, M.; Ciardi, D. R.; Daylan, T.; Delgado Mena, E.; Demangeon, O. D. S.; Diaz, R. F.; Gan, T.; Horne, K.; Hoyer, S.; Jenkins, J. M.; Jensen, E. L. N.; Kielkopf, J. F.; Kostov, V.; Latham, D. W.; Levine, A. M.; Lillo-Box, J.; Nielsen, L. D.; Osborn, H. P.; Ricker, G. R.; Rodrigues, J.; Santos, N. C.; Schwarz, R. P.; Seager, S.; Serrano Bell, J.; Shporer, A.; Stockdale, C.; Strom, P. A.; Tenenbaum, P.; Udry, S.; Wheatley, P. J.; Winn, J. N.; Ziegler, C.

doi:10.1093/mnras/stad1840

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 (T-eff = 5626 +/- 61 K) solar-like star with a mass of 0.950 +/- 0.010 M (circle dot) and a radius of 1.028 +/- 0.030 R-circle dot. The planet, TOI-908 b, is a 3.18 +/- 0.16 R-circle plus planet in a 3.18 d orbit. Radial velocity measurements from HARPS reveal TOI-908 b has a mass of approximately 16.1 +/- 4.1 M-circle plus, resulting in a bulk planetary density of 2.7(-0.4)(+0.2) 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.