TOI-969: a late-K dwarf with a hot mini-Neptune in the desert and an eccentric cold Jupiter,

LILLO-BOX, J.; GANDOLFI, D.; ARMSTRONG, D.J.; COLLINS, K.A.; NIELSEN, L.D.; LUQUE, R.; KORTH, J.; SOUSA, S.G.; QUINN, S.N.; ACUÑA, L.; HOWELL, S.B.; MORELLO, G.; HELLIER, C.; GIACALONE, S.; HOYER, S.; STASSUN, K.; PALLE, E.; AGUICHINE, A.; MOUSIS, O.; ADIBEKYAN, V.; SILVA, T. AZEVEDO; BARRADO, D.; DELEUIL, M.; EASTMAN, J.D.; FUKUI, A.; HAWTHORN, F.; IRWIN, J.M.; JENKINS, J.M.; LATHAM, D.W.; MURESAN, A.; NARITA, N.; PERSSON, C.M.; SANTERNE, A.; SANTOS, N.C.; SAVEL, A.B.; OSBORN, H.P.; TESKE, J.; WHEATLEY, P.J.; WINN, J.N.; BARROS, S.C.C.; BUTLER, R.P.; CALDWELL, D.A.; CHARBONNEAU, D.; CLOUTIER, R.; CRANE, J.D.; DEMANGEON, O.D.S.; DÍAZ, R.F.; DUMUSQUE, X.; ESPOSITO, M.; FALK, B.; GILL, H.; HOJJATPANAH, S.; KREIDBERG, L.; MIRELES, I.; OSBORN, A.; RICKER, G.R.; RODRIGUEZ, J.E.; SCHWARZ, R.P.; SEAGER, S.; BELL, J. SERRANO; SHECTMAN, S.A.; SHPORER, A.; VEZIE, M.; WANG, S.X.; ZHOU, G.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Año: 2023 vol. 669

0004-6361

Context. The current architecture of a given multi-planetary system is a key fingerprint of its past formation and dynamical evolution history. Long-term follow-up observations are key to complete their picture. Aims. In this paper, we focus on the confirmation and characterization of the components of the TOI-969 planetary system, where TESS detected a Neptune-size planet candidate in a very close-in orbit around a late K-dwarf star. Methods. We use a set of precise radial velocity observations from HARPS, PFS, and CORALIE instruments covering more than two years in combination with the TESS photometric light curve and other ground-based follow-up observations to confirm and characterize the components of this planetary system. Results. We find that TOI-969 b is a transiting close-in (Pb ∼ 1.82 days) mini-Neptune planet (Formula Presented), placing it on the lower boundary of the hot-Neptune desert (Teq,b = 941 ± 31 K). The analysis of its internal structure shows that TOI-969 b is a volatile-rich planet, suggesting it underwent an inward migration. The radial velocity model also favors the presence of a second massive body in the system, TOI-969 c, with a long period of (Formula Presented) days, a minimum mass of (Formula Presented), and a highly eccentric orbit of (Formula Presented). Conclusions. The TOI-969 planetary system is one of the few around K-dwarfs known to have this extended configuration going from a very close-in planet to a wide-separation gaseous giant. TOI-969 b has a transmission spectroscopy metric of 93 and orbits a moderately bright (G = 11.3 mag) star, making it an excellent target for atmospheric studies. The architecture of this planetary system can also provide valuable information about migration and formation of planetary systems.