J/ApJ/764/3ivo://CDS.VizieR/J/ApJ/764/3doi:10.26093/cds/vizier.17640003CDSRobertson P.Endl M.Cochran W.D.Dodson-Robinson S.E.2018-01-05T08:56:14Z2014-11-06T13:40:58ZCDS support team

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

cds-question@unistra.frm-starsspectroscopyThrough the McDonald Observatory M Dwarf Planet Search, we have acquired nearly 3000 high-resolution spectra of 93 late-type (K5-M5) stars over more than a decade using the High Resolution Spectrograph on the Hobby-Eberly Telescope. This sample provides a unique opportunity to investigate the occurrence of long-term stellar activity cycles for low-mass stars. In this paper, we examine the stellar activity of our targets as reflected in the H{alpha} feature. We have identified periodic signals for six stars, with periods ranging from days to more than 10 years, and find long-term trends for seven others. Stellar cycles with P>=1 year are present for at least 5% of our targets. Additionally, we present an analysis of the time-averaged activity levels of our sample, and search for correlations with other stellar properties. In particular, we find that more massive, earlier type (M0-M2) stars tend to be more active than later type dwarfs. Furthermore, high-metallicity stars tend to be more active at a given stellar mass. We also evaluate H{alpha} variability as a tracer of activity-induced radial velocity (RV) variation. For the M dwarf GJ 1170, H{alpha} variation reveals stellar activity patterns matching those seen in the RVs, mimicking the signal of a giant planet, and we find evidence that the previously identified stellar activity cycle of GJ 581 may be responsible for the recently retracted planet f in that system. In general, though, we find that H{alpha} is not frequently correlated with RV at the precision (typically 6-7m/s) of our measurements.2013ApJ...764....3Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/764/3CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/541/A9 : M dwarfs activity & radial velocity (Gomes da Silva+, 2012)J/A+A/540/A82 : CaIIHK emission in stars with planets (Krejcova+, 2012)J/AJ/143/93 : Rotational velocities in early-M stars (Reiners+, 2012)J/ApJ/743/48 : Stellar rotation periods & X luminosities (Wright+, 2011)J/A+A/521/A12 : RVs of nearby late-type stars (Maldonado+, 2010)J/A+A/514/A97 : HR spectra of Late-type stars (Lopez-Santiago+ 2010)J/A+A/511/A54 : Magnetic cycles & RV for 8 stars (Santos+, 2010)J/ApJ/725/875 : Chromospheric activity for CPS stars (Isaacson+, 2010)J/ApJ/723/954 : HIRES radial velocities of GJ 581 (Vogt+, 2010)J/A+A/507/487 : GJ 581 radial velocity curve (Mayor+, 2009)J/A+A/505/859 : M dwarfs radial velocities (Zechmeister+, 2009)J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)J/A+A/469/309 : Late-type stars chromospheric activity (Cincunegui+, 2007)J/MNRAS/367/1329 : Elemental abundances for 176 stars (Reddy+, 2006)J/AJ/128/426 : Subdwarfs in the SDSS (West+, 2004)J/A+AS/135/319 : ROSAT data of Nearby Stars (Huensch+ 1999)J/A+A/327/1039 : Structure and evolution of low-mass stars (Chabrier+ 1997)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/764/3https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/764/3http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/764/3https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/764/3https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/764/3http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/764/3GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/764/3/stars (List of stars (from table 1))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/764/3/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/764/3/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/764/3/stars?GETtext/xml+votable180.050000true109.880355832.83009060.0055555555555555566/2515 6346 8733 9415 10448 10683 19559 20324 27734 30407 31630 32161 44921https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/764/3?format=asciiOpticaldefaultJ/ApJ/764/3/starsList of stars (from table 1)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNiNumber of H{alpha} and CaI indices (table 2)meta.numberintnullableNameStar namemeta.id;meta.maincharn_NameNotes on the fit (1)meta.notecharl_PerLimit flag on Permeta.code.errorcharPer[3/2687]? Period for periodic signalsdtime.periodfloatnullablee_Per? Per uncertaintydstat.errorfloatnullableVarSimbad column added by the CDSmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/ApJ/764/3/table2H{alpha} and Ca I indices shown in Figures 4 and 6recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharBJDBarycentric Julian Date; BJD-2450000dtime.epochdoubleHa[0.0495/0.087] H{alpha} indexspect.index;em.line.Halphadoublee_Ha[0.0002/0.002] Uncertainty in Ha indexstat.errordoubleCaI[0.0214/0.028] Ca I indexspect.indexdoublee_CaI[0.0001/0.002] Uncertainty in CaI indexstat.errordouble