J/A+A/708/A232ivo://CDS.VizieR/J/A+A/708/A232CDSStoeva D.Stefanov A.K.Stefanov S.Y.Lafarga M.Bebekovska E.V.,Filomeno S.Gonzalez-Hernandez J.I.Suarez-Mascareno A.Rebolo R.,Nari N.Mestre J.M.Antonova D.Zaharieva E.Bozhilov V.Trifonov T.2026-04-09T17:33:06Z2026-04-09T17:29:38ZCDS support team

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

cds-question@unistra.frmultiple-starsk-starsexoplanetsradial-velocityspectroscopyvisible-astronomyDetection and characterisation of Jovian analogues in precision radial velocity (RV) measurements is gaining momentum due to the constantly increasing observational baseline of Doppler surveys. The occurrence rate of Jovian-mass exoplanets is crucial for understanding the architecture of planetary systems. However, long-period RV signals in Doppler surveys could also be induced by stellar magnetic cycles, leading to misinterpretations of planetary candidates. We investigate the long-term RV variability in the K-dwarf star GJ1137 (HD93083, HIP52521), a known Saturn-mass exoplanet host, and assess the role of stellar activity in shaping the observed signals. We analyse 13 years of archival high-precision spectroscopic observations obtained with the High Accuracy Radial velocity Planet Searcher spectrograph (HARPS). We performed an extensive spectroscopic analysis of the stellar activity indicators and applied an RV modelling approach, incorporating Keplerian fits, Gaussian process regression as a proxy for stellar activity, and other stellar activity diagnostics. Furthermore, we refined the orbital parameters and the minimum mass of the known exoplanet GJ 1137 b and searched for additional planetary candidates in the system. We detect a long-period RV signal that, if interpreted as planetary, would suggest the presence of a Jovian-analogue companion. However, our spectroscopic activity analysis provides strong evidence that this variability is induced by the star's long-term magnetic cycle P_cyc_=5870^+480^_-350_ days rather than by an orbiting planet. The signal is detected in both the full width at half maximum (FWHM) of the cross-correlation function and the chromospheric activity index logR'_HK. We measure the stellar rotation period to P_rot_=32.3^+1.2^_-1.3_ days and identify a significant short-period RV signal, which we attribute to a Super Earth with a period of 9.6412^+12^_-11_ days and a minimum mass of 5.12^+0.70^_-0.69_ Earth masses, making GJ 1137 a multiple-planet system.2026A&A...708A.232Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/708/A232CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/708/A232https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/708/A232http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/708/A232https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/708/A232https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/708/A232http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/708/A232GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/708/A232/tablea1HARPS Doppler measurements and activity index measurements of GJ 1137 evaluated using SERVAL and RACOON and their corresponding uncertaintiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintBJDBarycentric Julian Datedtime.epochdoubleRVservalNZPRadial Velocity (SERVAL)m/sphys.veloc;pos.heliocentricdoublee_RVservalNZPError in Radial Velocity (SERVAL)m/sstat.errordoubleRVracoonRadial Velocity (RACOON)km/sphys.veloc;pos.heliocentricdoublee_RVracoonError in Radial Velocity (RACOON)km/sstat.errordoubleHalphaH-alpha indexspect.indexdoublee_HalphaError in H-alpha indexstat.error;spect.linedoubleNaD1Sodium D1 indexspect.indexfloate_NaD1Error in Sodium D1 indexstat.errorfloatNaD2Sodium D2 indexspect.indexfloate_NaD2Error in Sodium D2 indexstat.errorfloatCRXChromatic indexspect.indexdoublee_CRXError in chromatic indexstat.errorfloatdLwLine width variationm/sspect.line.widthdoublee_dLwError in line width variationm/sstat.errordoubleRHKpR'HK chromospheric activity indicatorphot.flux;arith.ratiodoublee_RHKpError in chromospheric activity indicatorstat.errordoubleFWHMracoonFull width at half maximum (RACOON)km/sspect.line.widthdoublee_FWHMracoonError in FWHM (RACOON)km/sstat.errordoubleContracoonContrast (RACOON)%phot.flux;arith.ratiodoublee_ContracoonError in contrast (RACOON)%stat.errordoubleBISracoonBisector span (RACOON)km/sphys.velocdoublee_BISracoonError in bisector span (RACOON)km/sstat.errordoubleIDsetObservation set identifiermeta.id;obs.param;obsint