Data di Pubblicazione:
2024
Abstract:
We report the spectroscopic confirmation and fundamental properties of TOI−757 b, a mini−Neptune on a 17.5−d orbit transiting a bright star (V = 9.7 mag) discovered by the TESS mission. We acquired high−precision radial velocity measurements with the HARPS, ESPRESSO, and PFS spectrographs to confirm the planet detection and determine its mass. We also acquired space−borne transit photometry with the CHEOPS space telescope to place stronger constraints on the planet radius, supported with ground−based LCOGT photometry. WASP and KELT photometry were used to help constrain the stellar rotation period. We also determined the fundamental parameters of the host star. We find that TOI−757 b has a radius of Rp = 2.5 ± 0.1R. and a mass of Mp = 10.5+−2212M, implying a bulk density of ρp = 3.6 ± 0.8 g cm−3. Our internal composition modelling was unable to constrain the composition of TOI−757 b, highlighting the importance of atmospheric observations for the system. We also find the planet to be highly eccentric with e = 0.39+−000708, making it one of the very few highly eccentric planets among precisely characterized mini−Neptunes. Based on comparisons to other similar eccentric systems, we find a likely scenario for TOI−757 b’s formation to be high eccentricity migration due to a distant outer companion. We additionally propose the possibility of a more intrinsic explanation for the high eccentricity due to star−star interactions during the earlier epoch of the Galactic disc formation, given the low metallicity and older age of TOI−757.
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
planets and satellites: composition; planets and satellites: interiors; stars: individual: TOI-757 (TIC 130924120); techniques: photometric; techniques: radial velocities
Elenco autori:
Alqasim A.; Grieves N.; Rosario N.M.; Gandolfi D.; Livingston J.H.; Sousa S.; Collins K.A.; Teske J.K.; Fridlund M.; Egger J.A.; Cabrera J.; Hellier C.; Lanza A.F.; Van Eylen V.; Bouchy F.; Oelkers R.J.; Srdoc G.; Shectman S.; Gunther M.; Goffo E.; Wilson T.; Serrano L.M.; Brandeker A.; Wang S.X.; Heitzmann A.; Bonfanti A.; Fossati L.; Alibert Y.; Delrez L.; Sefako R.; Barros S.; Collins K.I.; Demangeon O.D.S.; Albrecht S.H.; Alonso R.; Asquier J.; Barczy T.; Barrado D.; Baumjohann W.; Beck T.; Benz W.; Billot N.; Borsato L.; Broeg C.; Bryant E.M.; Butler R.P.; Cochran W.D.; Cameron A.C.; Correia A.C.M.; Crane J.D.; Csizmadia Sz.; Cubillos P.E.; Davies M.B.; Daylan T.; Deleuil M.; Deline A.; Demory B.-O.; Derekas A.; Edwards B.; Ehrenreich D.; Erikson A.; Essack Z.; Fortier A.; Gazeas K.; Gillon M.; Gudel M.; Hasiba J.; Hatzes A.P.; Helling Ch.; Hirano T.; Howell S.B.; Hoyer S.; Isaak K.G.; Jenkins J.M.; Kanodia S.; Kiss L.L.; Korth J.; Lam K.W.F.; Laskar J.; des Etangs A.L.; Lendl M.; Lund M.B.; Luque R.; Mann A.W.; Magrin D.; Maxted P.F.L.; Mordasini C.; Narita N.; Nascimbeni V.; Nowak G.; Olofsson G.; Osborn H.P.; Osborne H.L.M.; Osip D.; Ottensamer R.; Pagano I.; Palle E.; Peter G.; Piotto G.; Pollacco D.; Queloz D.; Ragazzoni R.; Rando N.; Rauer H.; Redfield S.; Ribas I.; Rice M.; Ricker G.R.; Rieder M.; Salmon S.; Santos N.C.; Scandariato G.; Seager S.; Segransan D.; Shporer A.; Simon A.E.; Smith A.M.S.; Stalport M.; Szabo Gy.M.; Thompson I.; Twicken J.D.; Udry S.; Vanderspek R.; Van Grootel V.; Venturini J.; Villaver E.; Villasenor J.; Viotto V.; Walter I.; Walton N.A.; Winn J.N.; Yee S.W.
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