J/AJ/167/255ivo://CDS.VizieR/J/AJ/167/255doi:10.26093/cds/vizier.51670255CDSSilverstein M.L.Barclay T.Schlieder J.E.Collins K.A.Schwarz R.P.,Hord B.J.Rowe J.F.Kruse E.Astudillo-Defru N.Bonfils X.,Caldwell D.A.Charbonneau D.Cloutier R.Collins K.I.Daylan T.,Fong W.Jenkins J.M.Kunimoto M.McDermott S.Murgas F.Palle E.,Ricker G.R.Seager S.Shporer A.Tey E.Vanderspek R.Winn J.N.2024-11-06T20:20:14Z2024-06-28T07:35:18ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frexoplanetsm-starsvisible-astronomyThe nearby LHS-1678 (TOI-696) system contains two confirmed planets and a wide-orbit, likely brown-dwarf companion, which orbit an M2 dwarf with a unique evolutionary history. The host star occupies a narrow "gap" in the Hertzsprung-Russell diagram lower main sequence, associated with the M-dwarf fully convective boundary and long-term luminosity fluctuations. This system is one of only about a dozen M-dwarf multiplanet systems to date that hosts an ultra-short-period planet (USP). Here we validate and characterize a third planet in the LHS-1678 system using TESS Cycle 1 and 3 data and a new ensemble of ground-based light curves. LHS-1678d is a 0.98{+/-}0.07R{Earth} planet in a 4.97day orbit, with an insolation flux of 9.1_-0.8_^+0.9^S{Earth}. These properties place it near 4:3 mean motion resonance with LHS-1678c and in company with LHS-1678c in the Venus zone. LHS 1678 c and d are also twins in size and predicted mass, making them a powerful duo for comparative exoplanet studies. LHS-1678d joins its siblings as another compelling candidate for atmospheric measurements with the JWST and mass measurements using high-precision radial velocity techniques. Additionally, USP LHS-1678b breaks the "peas-in-a-pod" trend in this system although additional planets could fill in the "pod" beyond its orbit. LHS-1678's unique combination of system properties and their relative rarity among the ubiquity of compact multiplanet systems around M-dwarfs makes the system a valuable benchmark for testing theories of planet formation and evolution.2024AJ....167..255Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/167/255CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJS/197/2 : Transit timing observations from Kepler. I. (Ford+, 2011)J/ApJS/208/9 : Intrinsic colors & temperatures of PMS stars (Pecaut+, 2013)J/ApJS/222/14 : Planetary candidates 1st yr K2 mission (Vanderburg+, 2016)J/ApJ/834/17 : Mass & radius of planets, moons, low mass star (Chen+, 2017)J/AJ/154/191 : Solar neighborhood. XLII. New nearby subdwarfs (Jao+, 2017)J/AJ/155/180 : Catalog of cool dwarf targets for the TESS (Muirhead+, 2018)J/AJ/156/102 : TESS Input Catalog & Candidate Target List (Stassun+, 2018)J/AJ/155/48 : California-Kepler Survey. V. Masses and radii (Weiss+, 2018)J/A+A/639/A77 : Proxima Cen RV, FWHM and fluxes (Suarez Mascareno+, 2020)J/AJ/161/24 : TRICERATOPS predictions for 384 TOIs (Giacalone+, 2021)J/ApJS/254/39 : Exoplanet candidates TESS first 2yr obs (Guerrero+, 2021)J/MNRAS/512/2062 : 10 exoplanet systems transit timing (Basturk+, 2022)J/other/Sci/377.1211 : RV and LC of 8 M dwarf stars with planets (Luque+, 2022)J/AJ/166/63 : Mind the Gap. I. Ha activity for M-Dwarfs (Jao+, 2023)J/AJ/165/265 : Properties of 363 M-dwarfs from TESS (Ment+, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/167/255https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/167/255http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/167/255https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/167/255https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/167/255http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/167/255GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/167/255/table4Exoplanet Transit TimesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPlanetPlanet identifiermeta.id;meta.maincharTransit[1411/2587] Transit time; BJD-2457000dtime.durationdoubleE_Transit[0.003/0.1] Upper 1-{sigma} uncertainty in Transitdstat.error;stat.maxdoublee_Transit[0.003/0.08] Lower 1-{sigma} uncertainty in Transitdstat.errordoubleIndex[1/1361] Transit index (1)meta.id;meta.numberintTelTelescope used; LCO, MEarth-S, or TESSinstr.telchar