J/AJ/160/114ivo://CDS.VizieR/J/AJ/160/114doi:10.26093/cds/vizier.51600114CDSCarleo I.Gandolfi D.Barragan O.Livingston J.H.Persson C.M.,Lam K.W.F.Vidotto A.Lund M.B.D'Angelo C.V.Collins K.A.Fossati L.,Howard A.W.Kubyshkina D.Brahm R.Oklopcic A.Molliere P.Redfield S.,Serrano L.M.Dai F.Fridlund M.Borsa F.Korth J.Esposito M.,Diaz M.R.Nielsen L.D.Hellier C.Mathur S.Deeg H.J.Hatzes A.P.,Benatti S.Rodler F.Alarcon J.Spina L.Santos A.R.G.Georgieva I.,Garcia R.A.Gonzalez-Cuesta L.Ricker G.R.Vanderspek R.Latham D.W.,Seager S.Winn J.N.Jenkins J.M.Albrecht S.Batalha N.M.Beard C.,Boyd P.T.Bouchy F.Burt J.A.Butler R.P.Cabrera J.Chontos A.,Ciardi D.R.Cochran W.D.Collins K.I.Crane J.D.Crossfield I.,Csizmadia S.Dragomir D.Dressing C.Eigmuller P.Endl M.Erikson A.,Espinoza N.Fausnaugh M.Feng F.Flowers E.Fulton B.Gonzales E.J.,Grieves N.Grziwa S.Guenther E.W.Guerrero N.M.Henning T.Hidalgo D.,Hirano T.Hjorth M.Huber D.Isaacson H.Jones M.Jordan A.Kabath P.,Kane S.R.Knudstrup E.Lubin J.Luque R.Mireles I.Narita N.,Nespral D.Niraula P.Nowak G.Palle E.Patzold M.Petigura E.A.,Prieto-Arranz J.Rauer H.Robertson P.Rose M.E.Roy A.Sarkis P.,Schlieder J.E.Segransan D.Shectman S.Skarka M.Smith A.M.S.,Smith J.C.Stassun K.Teske J.Twicken J.D.Van Eylen V.Wang S.,Weiss L.M.Wyttenbach A.2021-07-05T07:35:57Z2021-01-06T09:44:23ZCDS support team

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

cds-question@unistra.frexoplanetsdwarf-starsvisible-astronomyspectroscopyinfrared-astronomyradial-velocityWe report the discovery of a warm Neptune and a hot sub-Neptune transiting TOI-421 (BD-141137, TIC94986319), a bright (V=9.9) G9 dwarf star in a visual binary system observed by the Transiting Exoplanet Survey Satellite (TESS) space mission in Sectors 5 and 6. We performed ground-based follow-up observations-comprised of Las Cumbres Observatory Global Telescope transit photometry, NIRC2 adaptive optics imaging, and FIbre-fed Echelle Spectrograph, CORALIE, High Accuracy Radial velocity Planet Searcher, High Resolution Echelle Spectrometer, and Planet Finder Spectrograph high-precision Doppler measurements-and confirmed the planetary nature of the 16 day transiting candidate announced by the TESS team. We discovered an additional radial velocity signal with a period of five days induced by the presence of a second planet in the system, which we also found to transit its host star. We found that the inner mini-Neptune, TOI-421b, has an orbital period of Pb=5.19672{+/-}0.00049days, a mass of Mb=7.17{+/-}0.66M{Earth}, and a radius of Rb=2.68_-0.18_^+0.19^R{Earth}, whereas the outer warm Neptune, TOI-421c, has a period of Pc=16.06819{+/-}0.00035days, a mass of Mc=16.42_-1.04_^+1.06^M{Earth}, a radius of Rc=5.09_-0.15_^+0.16^R{Earth}, and a density of {rho}c=0.685_-0.072_^+0.080^g/cm^3^. With its characteristics, the outer planet ({rho}c=0.685_-0.072_^+0.080^g/cm^3^) is placed in the intriguing class of the super-puffy mini-Neptunes. TOI-421b and TOI-421c are found to be well-suited for atmospheric characterization. Our atmospheric simulations predict significant Ly{alpha} transit absorption, due to strong hydrogen escape in both planets, as well as the presence of detectable CH4 in the atmosphere of TOI-421c if equilibrium chemistry is assumed.2020AJ....160..114Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/160/114CatalogResearchIsServedByTAP VizieR generic servicerelated-toI/337 : Gaia DR1 (Gaia Collaboration, 2016)I/345 : Gaia DR2 (Gaia Collaboration, 2018)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/A+A/397/147 : Activity-rotation relation. in stars (Pizzolato+,2003)J/A+A/468/1115 : Thorium and argon lines in the visible (Lovis+, 2007)J/ApJ/687/1264 : Age estimation for solar-type dwarfs (Mamajek+, 2008)J/other/A+ARV/17.251 : Stars observed with Doppler imaging (Strassmeier, 2009)J/ApJ/720/1118 : i-band photometry of HAT-P-16 (Buchhave+, 2010)J/A+A/529/A75 : Limb-darkening coefficients (Claret+, 2011)J/ApJS/197/8 : Kepler's candid. multiple planets (Lissauer+, 2011)J/ApJ/743/48 : Stars with rot. per. & X-ray luminosities (Wright+, 2011)J/ApJS/208/9 : Intrinsic colors & temper. of PMS stars (Pecaut+,2013)J/A+A/564/A125 : AGN Torus model comparison of AGN CDFS (Buchner+, 2014)J/A+A/572/A34 : Pulsating solar-like stars in Kepler (Garcia+, 2014)J/ApJ/784/45 : Kepler's multiple planet candidates. III. (Rowe+, 2014)J/ApJ/809/77 : Transiting Exoplanet Survey Satellite (Sullivan+, 2015)J/A+A/605/A111 : Surface rotation of Kepler red giant stars (Ceillier+, 2017)J/MNRAS/466/1868 : Neptune-like planets overabundance (Cubillos+, 2017)J/AJ/154/226 : Photometry and radial velocities of K2-131 (Dai+, 2017)J/AJ/153/71 : Kepler follow-up obs. program. I. Imaging (Furlan+, 2017)J/AJ/154/123 : RV follow-up of the HD3167 system (Gandolfi+, 2017)J/ApJ/836/77 : Library of high-S/N optical spectra FGKM stars (Yee+, 2017)J/ApJS/239/2 : Simulated exoplanets TESS list of targets (Barclay+, 2018)J/A+A/612/A95 : K2-141 b radial velocity and light curve (Barragan+, 2018)J/A+A/619/L10 : pi Men radial velocity curves (Gandolfi+, 2018)J/AJ/156/102 : TESS Input Catalog & Candidate Target List (Stassun+, 2018)J/AJ/158/45 : TESS light curve & RVs for HD 1397 (Brahm+, 2019)J/ApJ/876/L24 : HARPS radial velocities host star HD15337 (Gandolfi+, 2019)J/ApJ/874/107 : HARPS-N solar radial velocities & activity (Milbourne+,2019)J/A+A/628/A64 : EPIC 212036875b griz light curves (Persson+, 2019)J/AJ/158/177 : Near-resonance in system sub-Neptunes TESS (Quinn+, 2019)J/ApJS/244/21 : Surface rotation & activity Kepler stars I. (Santos+, 2019)J/ApJS/241/12 : Asteroseismic Target List (ATL) for TESS (Schofield+, 2019)J/A+A/638/A5 : HD 285507 & AD Leo light and velocity curves (Carleo+,2020)J/A+A/634/L4 : HST/STIS FUV spectra of K2-18 (dos Santos+, 2020)J/AJ/159/145 : RVs and opt. photom. of the host star TOI-677 (Jordan+,2020)J/AJ/159/57 : HST spectro. LCs of Kepler 51b & 51d (Libby-Roberts+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/160/114https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/160/114http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/160/114https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/160/114https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/160/114http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/160/114GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/AJ/160/114/rvCombined table from original tablesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTelTelescope usedmeta.id;instrcharBJDBarycentric Julian Date; BJD-2450000 (1)dtime.epochdoubleRVelRadial velocitykm/sphys.veloc;pos.heliocentricfloate_RVelError on RVel ({sigma}_RV_)km/sstat.error;spect.dopplerVelocfloatBIS? Bisector spankm/sstat.fit.residualfloatnullableFWHM? Full width at half maximumkm/sspect.line.widthfloatnullablelogRHK? CaII H and K lines activity indicatorspect.index;em.line.Halphafloatnullablee_logRHK? Error on logRHKstat.errorfloatnullableTexpExposurer timestime.epochintS/NSignal to noise ratio at 550nmpixel**-1stat.snrint