J/AJ/155/106ivo://CDS.VizieR/J/AJ/155/106doi:10.26093/cds/vizier.51550106CDSMillholland S.Laughlin G.Teske J.Butler R.P.Burt J.Holden B.,Vogt S.Crane J.Shectman S.Thompson I.2019-01-07T09:07:17Z2018-10-29T09:04:36ZCDS support team

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

cds-question@unistra.frvariable-starsradial-velocityexoplanetsGliese 876 harbors one of the most dynamically rich and well-studied exoplanetary systems. The nearby M4V dwarf hosts four known planets, the outer three of which are trapped in a Laplace mean-motion resonance. A thorough characterization of the complex resonant perturbations exhibited by the orbiting planets, and the chaotic dynamics therein, is key to a complete picture of the system's formation and evolutionary history. Here we present a reanalysis of the system using 6 yr of new radial velocity (RV) data from four instruments. These new data augment and more than double the size of the decades-long collection of existing velocity measurements. We provide updated estimates of the system parameters by employing a computationally efficient Wisdom-Holman N-body symplectic integrator, coupled with a Gaussian process (GP) regression model to account for correlated stellar noise. Experiments with synthetic RV data show that the dynamical characterization of the system can differ depending on whether a white-noise or correlated-noise model is adopted. Despite there being a region of stability for an additional planet in the resonant chain, we find no evidence for one. Our new parameter estimates place the system even deeper into resonance than previously thought and suggest that the system might be in a low-energy, quasi-regular double apsidal corotation resonance. This result and others will be used in a subsequent study on the primordial migration processes responsible for the formation of the resonant chain.2018AJ....155..106Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/155/106CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/634/625 : Radial velocities and photometry of GJ 876 (Rivera+, 2005)J/A+A/511/A21 : Radial velocities of GJ876 planetary system (Correia+, 2010)J/ApJ/719/890 : Keck radial velocities of GJ 876 (Rivera+, 2010)J/ApJS/200/15 : HARPS-TERRA project. I. (Anglada-Escude+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/155/106https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/155/106http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/155/106https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/155/106https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/155/106http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/155/106GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/AJ/155/106/table2New Doppler velocity measurements of the GJ 876 system from four instrumentsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSample[1/6] RV sample (1)src.sampleintf_Sample[0/1] Flag on Sample indicating new observations (1=New)meta.codeintBJDBarycentric Julian Date of observationdtime.epochdoubleRV[-333.2757062/423.62] Radial velocitym/sphys.veloc;pos.heliocentricdoublee_RV[0.399202018/8.01] Uncertainty in RVm/sstat.errordoubleS[0.3439/1.8697] Mount Wilson Ca HK activity indexmeta.code;spect.indexdouble