J/AJ/166/62ivo://CDS.VizieR/J/AJ/166/62doi:10.26093/cds/vizier.51660062CDSBlunt S.Carvalho A.David T.J.Beichman C.Zink J.K.Gaidos E.,Behmard A.Bouma L.G.Cody D.Dai F.Foreman-Mackey D.Grunblatt S.,Howard A.W.Kosiarek M.Knutson H.A.Rubenzahl R.A.Beard C.,Chontos A.Giacalone S.Hirano T.Johnson M.C.Lubin J.,Akana Murphy J.M.Petigura E.A.Van Zandt J.Weiss L.2024-11-06T20:18:53Z2024-02-23T09:30:15ZCDS support team

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

cds-question@unistra.frpre-main-sequence-starsexoplanetsvisible-astronomyspectroscopyradial-velocityMass, radius, and age measurements of young (<~100Myr) planets have the power to shape our understanding of planet formation. However, young stars tend to be extremely variable in both photometry and radial velocity (RV) measurements, which makes constraining these properties challenging. The V1298 Tau system of four ~0.5RJup planets transiting a pre-main-sequence star presents an important, if stress-inducing, opportunity to observe and measure directly the properties of infant planets. Suarez Mascareno et al. published radial-velocity-derived masses for two of the V1298-Tau planets using a state-of-the-art Gaussian process regression framework. The planetary densities computed from these masses were surprisingly high, implying extremely rapid contraction after formation in tension with most existing planet-formation theories. In an effort to constrain further the masses of the V1298-Tau planets, we obtained 36 RVs using Keck/HIRES, and analyzed them in concert with published RVs and photometry. Through performing a suite of cross-validation tests, we found evidence that the preferred model of Suarez Mascareno et al. suffers from overfitting, defined as the inability to predict unseen data, rendering the masses unreliable. We detail several potential causes of this overfitting, many of which may be important for other RV analyses of other active stars, and recommend that additional time and resources be allocated to understanding and mitigating activity in active young stars such as V1298-Tau.2023AJ....166...62Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/166/62CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/AJ/121/3160 : JHK photometry near the Trapezium region (Carpenter+, 2001)J/other/Sci/330.653 : Detected planets in the Eta-Earth Survey (Howard+, 2010)J/ApJ/790/146 : Planets in Kepler multi-transiting systems (Fabrycky+, 2014)J/ApJ/830/46 : Radial velocities 3 Neptunemass planet hosts (Fulton+, 2016)J/AJ/152/204 : HARPS-N radial velocities of HD179070 (Lopez-Morales+, 2016)J/AJ/154/226 : Photometry and radial velocities of K2-131 (Dai+, 2017)J/MNRAS/472/1618 : Kepler study of starspot lifetimes (Giles+, 2017)J/AJ/158/58 : Autoregressive planet search Kepler stars (Caceres+, 2019)J/ApJ/871/187 : Spot parameters on KIC solar-type stars (Namekata+, 2019)J/AJ/159/2 : K219b & c transit time & radial velocities (Petigura+, 2020)J/AJ/163/121 : Radial velocity & light curve of Kepler 1627A (Bouma+, 2022)J/AJ/163/247 : HIRES, PEPSI & TRES RVel of V1298 Tau (Johnson+, 2022)J/AJ/163/156 : THYME. VI. TOI-1227 radial velocity (Mann+, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/166/62https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/166/62http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/166/62https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/166/62https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/166/62http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/166/62GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/AJ/166/62/table1New HIRES radial velocity datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJD[1438/1886] Barycentric Julian Date at TDB; BDJ-2457000 (1)dtime.epochdoubleRVel[-260/388] Radial Velocitym/sspect.dopplerVelocfloate_RVel[7/20] Uncertainty in RVelm/sstat.error;spect.dopplerVelocfloat