J/AJ/167/282ivo://CDS.VizieR/J/AJ/167/282doi:10.26093/cds/vizier.51670282CDSLange S.Murphy J.M.A.Batalha N.M.Crossfield I.J.M.Dressing C.D.,Fulton B.Howard A.W.Huber D.Isaacson H.Kane S.R.Petigura E.A.,Robertson P.Weiss L.M.Behmard A.Beard C.Blunt S.Brinkman C.L.,Chontos A.Dai F.Dalba P.A.Fetherolf T.Giacalone S.Hill M.L.,Holcomb R.Lubin J.MacDougall M.G.Mayo A.W.Mocnik T.,Pidhorodetska D.Polanski A.S.Rice M.Rosenthal L.J.Rubenzahl R.A.,Scarsdale N.Turtelboom E.V.Van Zandt J.Ciardi D.R.Boyle A.W.2025-05-05T20:07:57Z2024-07-01T08:58:05ZCDS support team

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

cds-question@unistra.frexoplanetsvisible-astronomyspectroscopyradial-velocityWe confirm a massive sub-Neptune-sized planet on a P=22.8 days orbit around the star TOI-1824 (Teff=5200 K, V=9.7 mag). TESS first identified TOI-1824 b (formerly TOI-1824.01) as an object of interest in 2020 April after two transits in Sector 22 were matched with a single transit in Sector 21. TOI-1824 was subsequently targeted for ground-based Doppler monitoring with Keck-HIRES and APF-Levy. Using a joint model of the TESS photometry, radial velocities, and Ca ii H and K emission measurements as an activity indicator, we find that TOI-1824b is an unusually dense sub-Neptune. The planet has a radius Rp=2.63{+/-}0.15R{Earth} and mass Mp=18.5{+/-}3.2M{Earth}, implying a bulk density of 5.6{+/-}1.4g/cm^3^. TOI-1824 b's mass and radius situate it near a small group of "superdense sub-Neptunes" (Rp<~3R{Earth} and Mp>~20M{Earth}). While the formation mechanism of superdense sub-Neptunes is a mystery, one possible explanation is the constructive collision of primordial icy cores; such giant impacts would drive atmospheric escape and could help explain these planets' apparent lack of massive envelopes. We discuss TOI-1824b in the context of these overdense planets, whose unique location in the exoplanet mass-radius plane make them a potentially valuable tracer of planet formation.2024AJ....167..282Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/167/282CatalogResearchIsServedByTAP VizieR generic servicerelated-toIII/150 : Perkins Revised MK Types for the Cooler Stars (Keenan+ 1989)I/337 : Gaia DR1 (Gaia Collaboration, 2016)IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)I/345 : Gaia DR2 (Gaia Collaboration, 2018)I/350 : Gaia EDR3 (Gaia Collaboration, 2020)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)J/ApJ/764/3 : H{alpha} indices in M low-mass stars (Robertson+, 2013)J/ApJS/210/20 : Small Kepler planets radial velocities (Marcy+, 2014)J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014)J/ApJ/825/19 : Mass-radius relationship planets with Rp<4 (Wolfgang+, 2016)J/AJ/154/109 : California-Kepler Survey. III. Planet radii (Fulton+, 2017)J/AJ/153/71 : Kepler follow-up obs program. I. Imaging (Furlan+, 2017)J/AJ/154/5 : Transit timing variations 145 Kepler planets (Hadden+, 2017)J/ApJ/844/102 : KIC star plxes from asteroseismology vs Gaia (Huber+, 2017)J/AJ/153/257 : Comoving stars in Gaia DR1 (Oh+, 2017)J/AJ/154/107 : California-Kepler Survey. I. 1305 stars (Petigura+, 2017)J/ApJ/836/77 : Library of high-S/N optical spectra of FGKM stars (Yee+, 2017)J/AJ/155/203 : HARPS-N RVs & activity indicators Kepler-1655 (Haywood+, 2018)J/A+A/623/A114 : Light curve of K2-292 (HD 119130) (Luque+, 2019)J/AJ/159/280 : Gaia-Kepler star properties cat. I. KIC stars (Berger+, 2020)J/AJ/159/241 : TESS-Keck Survey. I. HD332231 Radial Velocities (Dalba+, 2020)J/ApJS/254/39 : Exoplanet candidates from TESS first 2yr obs (Guerrero+, 2021)J/AJ/162/265 : TESS-Keck survey. VI. HIP-97166 rvel (Macdougall+, 2021)J/AJ/161/70 : Rvel for WASP-107 with HIRES & CORALIE (Piaulet+, 2021)J/AJ/162/89 : HIRES radial velocity follow up for Kepler-129 (Zhang+, 2021)J/AJ/163/160 : Properties of 170 TOI hosts and companions (Behmard+, 2022)J/AJ/163/61 : TESS-Keck Survey VIII. TOI-2180 radial velocity (Dalba+, 2022)J/AJ/163/101 : TESS-Keck survey. IX. Rvel of HD1919139 (Lubin+, 2022)J/other/Sci/377.1211 : RV and LC of 8 M dwarf stars with planets (Luque+, 2022)J/MNRAS/511/1043 : Sub-Neptunes transiting TOI-1064 (Wilson+, 2022)J/AJ/166/62 : New HIRES radial velocity data for V1298 Tau (Blunt+, 2023)J/AJ/167/70 : TESS-Keck Survey. XVII. TOI-1136 rvel (Beard+, 2024)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/167/282https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/167/282http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/167/282https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/167/282https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/167/282http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/167/282GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/167/282/table2TOI-1824 radial velocities and SHK valuesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[2458967/2459978] Barycentric Julian Date at TDBdtime.epochdoubleRVel[-26.12/30.35] Radial velocity, m/s (1)m.s**-1spect.dopplerVelocfloate_RVel[1.12/6.78] Uncertainty in RVel (2)m.s**-1stat.error;spect.dopplerVelocfloatSHK[0.33/0.406]? Mt. Wilson CaII HK activity indexspect.indexfloatnullablee_SHK[0.002/0.002]? Uncertainty in SHKstat.errorfloatnullableTelTelescope used; APF or HIRESinstr.telchar