TOI-5108 and TOI 5786 radial velocities

We report the discovery and characterization of two sub-Saturns from the Transiting Exoplanet Survey Satellite (TESS) using high-resolution spectroscopic observations from the MaHPS spectrograph at the Wendelstein Observatory and the SOPHIE spectrograph at the Haute-Provence Observatory. Combining photometry from TESS, KeplerCam, LCOGT, and MuSCAT2 with the radial velocity measurements from MaHPS and SOPHIE we measure precise radii and masses for both planets. TOI-5108 b is a sub-Saturn with a radius of 6.6+/-0.1R_{Earth} and a mass of 32+/-5M{Earth} TOI-5786 b is similar to Saturn with a radius of 8.63+/-0.12R{Earth} and a mass of 72+/-8M{Earth}. Both planets are close to their host stars with periods of 6.75 days and 12.78 days respectively. This puts TOI-5108 b just inside the bounds of the Neptune desert while TOI-5786 b is right above the upper edge. We estimate hydrogen-helium envelope mass fractions of 38% for TOI-5108 b and 74% for TOI-5786 b. However, using a model for the interior structure that includes tidal effects the envelope fraction of TOI-5108 b could be much lower (~20$) depending on the obliquity. We estimate mass-loss rates between 1.0x10^9^g/s and 9.8x10^9^g/s for TOI-5108 b and between 3.6x10^8^g/s and 3.5x10^9^g/s for TOI-5786 b. Given their masses, this means that both planets are stable against photoevaporation. Furthermore, at these mass-loss rates, there is likely no detectable signal in the metastable helium triplet with the James Webb Space Telescope. We also detect a transit signal for a second planet candidate around TOI-5786 with a period of 6.998 days and a radius of 3.90+/-0.16R{Earth} Using our RV data and photodynamical modeling, we are able to provide a 3-{sigma} upper limit of 26.5M{Earth}_ for the mass of the potential inner companion to TOI-5786 b.

Identifier
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/A+A/694/A143
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/694/A143
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/694/A143
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/A+A/694/A143
Provenance
Creator Thomas L.; Hebrard G.; Kellermann H.; Korth J.; Heidari N.; Forveille T.,Sousa S.G.; Schoeller L.; Riffeser A.; Goessl C.; Serrano Bell J.,Kiefer F.; Hara N.; Grupp F.; Ehrhardt J.; Murgas F.; Collins K.A.,Bieryla A.; Parviainen H.; Belinski A.A.; Esparza-Borges E.; Ciardi D.R.,Clark C.A.; Fukui A.; Gilbert E.A.; Hopp U.; Ikuta K.; Jenkins J.M.,Latham D.W.; Narita N.; Nielsen L.D.; Quinn S.N.; Palle E.; Pippert J.-N.,Polanski A.S.; Ries C.; Schmidt M.; Schwarz R.P.; Seager S.; Strakhov I.A.,Striegel S.; van Eyken J.C.; Watanabe N.; Watkins C.N.; Winn J.N.,Ziegler C.; Zoeller R.
Publisher CDS
Publication Year 2025
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Exoplanet Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy