J/ApJ/874/107ivo://CDS.VizieR/J/ApJ/874/107doi:10.26093/cds/vizier.18740107CDSMilbourne T.W.Haywood R.D.Phillips D.F.Saar S.H.Cegla H.M.,Cameron A.C.Costes J.Dumusque X.Langellier N.Latham D.W.,Maldonado J.Malavolta L.Mortier A.III M.L.P.Thompson S.,Watson C.A.Bouchy F.Buchschacher N.Cecconi M.Charbonneau D.,Cosentino R.Ghedina A.Glenday A.G.Gonzalez M.Li C.-H.Lodi M.,Lopez-Morales M.Lovis C.Mayor M.Micela G.Molinari E.Pepe F.,Piotto G.Rice K.Sasselov D.Segransan D.Sozzetti A.Szentgyorgyi A.,Udry S.Walsworth R.L.2021-09-08T06:48:26Z2020-09-24T16:58:59ZCDS support team

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

cds-question@unistra.frthe-sunradial-velocityState-of-the-art radial-velocity (RV) exoplanet searches are currently limited by RV signals arising from stellar magnetic activity. We analyze solar observations acquired over a 3yr period during the decline of Carrington Cycle 24 to test models of RV variation of Sun-like stars. A purpose-built solar telescope at the High Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) provides disk-integrated solar spectra, from which we extract RVs and logR'_HK_. The Solar Dynamics Observatory (SDO) provides disk-resolved images of magnetic activity. The Solar Radiation and Climate Experiment (SORCE) provides near-continuous solar photometry, analogous to a Kepler light curve. We verify that the SORCE photometry and HARPS-N logR'_HK_ correlate strongly with the SDO-derived magnetic filling factor, while the HARPS-N RV variations do not. To explain this discrepancy, we test existing models of RV variations. We estimate the contributions of the suppression of convective blueshift and the rotational imbalance due to brightness inhomogeneities to the observed HARPS-N RVs. We investigate the time variation of these contributions over several rotation periods, and how these contributions depend on the area of active regions. We find that magnetic active regions smaller than 60Mm^2^ do not significantly suppress convective blueshift. Our area-dependent model reduces the amplitude of activity-induced RV variations by a factor of two. The present study highlights the need to identify a proxy that correlates specifically with large, bright magnetic regions on the surfaces of exoplanet-hosting stars.2019ApJ...874..107Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/874/107CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/390/717 : Sun Solar Velocities in 1989-99 (IRIS++) (Salabert+, 2002)J/AJ/138/312 : Activity of bright solar analogs (Hall+, 2009)J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)J/A+A/544/A125 : Solar lines from Ceres spectra (Molaro+, 2012)J/A+A/622/A85 : Starspot rotation rates vs. activity cycles (Nielsen+, 2019)J/A+A/627/A118 : Optical activity indicators (Maldonado+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/874/107https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/874/107http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/874/107https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/874/107https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/874/107http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/874/107GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/874/107/table3The daily-averaged solar telescope and SDO/HMI data products used in our analysisrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[1.4/790.6] Julian Date; JD-2457222.5dtime.epochfloatRVel[98.4/113.2] Radial velocitym/sphys.veloc;pos.heliocentricfloate_RVel[0.39/0.6] Uncertainty in RVelm/sstat.error;spect.dopplerVelocfloatlogR'HK[-5.01/-4.95] Measured logR'_HK_ valuephot.flux;arith.ratiofloatfspot[0/2.31] Spot filling factor * 1000arith.factor;stat.fillingfloatfbright[15.38/59.11] Bright filling factor * 1000arith.factor;stat.fillingfloatDelvp[-1.3/0.8] HMI-derived photometric velocity shiftm/sphys.veloc;arith.difffloatDelvc[1.7/10.6] HMI-derived convective velocity shiftm/sphys.veloc;arith.difffloatDelvcs[0.02/6.8] Convective velocity shift (1)m/sphys.veloc;arith.difffloatDelvcl[1.7/4.1] Convective velocity shift (2)m/sphys.veloc;arith.difffloat