TESS-Keck survey. VI. HIP-97166 radial velocity

DOI

We report the discovery of HIP-97166b (TOI-1255b), a transiting sub-Neptune on a 10.3day orbit around a K0 dwarf 68pc from Earth. This planet was identified in a systematic search of TESS Objects of Interest for planets with eccentric orbits, based on a mismatch between the observed transit duration and the expected duration for a circular orbit. We confirmed the planetary nature of HIP-97166b with ground-based radial-velocity measurements and measured a mass of M_b_=20{+/-}2M{Earth} along with a radius of R_b_=2.7{+/-}0.1R{Earth} from photometry. We detected an additional nontransiting planetary companion with M_c_sini=10{+/-}2M{Earth} on a 16.8day orbit. While the short transit duration of the inner planet initially suggested a high eccentricity, a joint RV-photometry analysis revealed a high impact parameter b=0.84{+/-}0.03 and a moderate eccentricity. Modeling the dynamics with the condition that the system remain stable over >10^5^ orbits yielded eccentricity constraints e_b_=0.16{+/-}0.03 and e_c_<0.25. The eccentricity we find for planet b is above average for the small population of sub-Neptunes with well-measured eccentricities. We explored the plausible formation pathways of this system, proposing an early instability and merger event to explain the high density of the inner planet at 5.3{+/-}0.9g/cc as well as its moderate eccentricity and proximity to a 5:3 mean-motion resonance.

Identifier
DOI http://doi.org/10.26093/cds/vizier.51620265
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/AJ/162/265
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/162/265
Related Identifier https://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/162/265
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/AJ/162/265
Provenance
Creator Macdougall M.G.; Petigura E.A.; Angelo I.; Lubin J.; Batalha N.M.,Beard C.; Behmard A.; Blunt S.; Brinkman C.; Chontos A.; Crossfield I.J.M.,Dai F.; Dalba P.A.; Dressing C.; Fulton B.; Giacalone S.; Hill M.L.,Howard A.W.; Huber D.; Isaacson H.; Kane S.R.; Mayo A.; Mocnik T.,Murphy J.M.A.; Polanski A.; Rice M.; Robertson P.; Rosenthal L.J.; Roy A.,Rubenzahl R.A.; Scarsdale N.; Turtelboom E.; Van Zandt J.; Weiss L.M.,Matthews E.; Jenkins J.M.; Latham D.W.; Ricker G.R.; Seager S.,Vanderspek R.K.; Winn J.N.; Brasseur C.E.; Doty J.; Fausnaugh M.,Guerrero N.; Henze C.; Lund M.B.; Shporer A.
Publisher CDS
Publication Year 2022
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; Interdisciplinary Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy