J/A+A/710/A311ivo://CDS.VizieR/J/A+A/710/A311CDSNagel E.Koehler J.Zechmeister M.Rains A.D.Seemann U.Hatzes A.,Reiners A.Piskunov N.Boldt-Christmas L.Bristow P.Chaturvedi P.,Cont D.Czesla S.Dorn R.J.Guenther E.Jung Y.Kochukhov O.,Lesjak F.Lucertini F.Marquart T.Nortmann L.Rengel M.Rodler F.,Smoker J.V.2026-06-25T07:48:23Z2026-06-25T08:47:24ZCDS support team

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

cds-question@unistra.frmultiple-starsexoplanetsradial-velocityWe present the first planet mass measurement obtained with CRIRES+ radial velocity (RV) observations using the K-band gas cell. Our target, LHS 3844 b (TOI-136), is a transiting super-Earth with radius R_b_=1.286R_{earth}_ and an orbital period of P_b_=0.462929709d, placing it in the class of ultra-short-period (USP) planets. The host star LHS 3844 is an old (7.8+-1.6Gyr), slowly rotating (P_rot_=130.0d) M5.0 dwarf with M=0.151M_{sun} at a distance of 15pc (V=15.2mag, K=9.2mag). Combining our CRIRES+ RVs with archival ESPRESSO spectra, and confirming the signal in each dataset independently, we detect periodic RV variations with a semi-amplitude K_b_=6.95m/s, implying a planetary mass of m_b_=2.37+/-0.25M_{earth}_ and a bulk density of rho_b_=6.15g/cm^3^, consistent with a predominantly rocky composition. We further find excess RV variability that may be attributed to stellar jitter or to an additional planetary signal, for which we identify a tentative super-Earth candidate with a period of ~6.88d. Owing to its proximity to its M-dwarf host, LHS 3844 b experiences intense irradiation and is unlikely to retain a substantial H/He envelope. Interior modeling places an upper limit on the iron-core mass fraction, which is consistent with an Earth-like rocky composition. With an emission spectroscopy metric (ESM) of 28, LHS 3844 b is a prime JWST target for atmospheric and surface characterization and the most promising surface-characterization target known. Phase-curve spectroscopy may reveal its surface mineralogy and enable the first robust detection of exoplanet surface spectral features. Our results demonstrate that near-infrared RVs obtained with CRIRES+ enable robust mass measurements of super-Earths orbiting late M dwarfs.2026A&A...710A.311Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/710/A311CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/710/A311https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/710/A311http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/710/A311https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/710/A311https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/710/A311http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/710/A311GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/710/A311/rvcriresCRIRES+ radial velocity time-series of LHS 3844 (table B1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Datedtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricfloate_RVRadial velocity uncertaintym/sstat.errorfloatJ/A+A/710/A311/rvespresESPRESSO radial velocity time-series of LHS 3844 (table B2)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Datedtime.epochdoubleRVRadial velocitym/sphys.veloc;pos.heliocentricfloate_RVRadial velocity uncertaintym/sstat.errorfloat