J/ApJ/824/1ivo://CDS.VizieR/J/ApJ/824/1doi:10.26093/cds/vizier.18240001CDSNeilson H.R.Engle S.G.Guinan E.F.Bisol A.C.Butterworth N.2017-06-12T08:25:26Z2016-09-22T13:57:32ZCDS support team

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

cds-question@unistra.frvariable-starsphotometryThe classical Cepheid l Carinae is an essential calibrator of the Cepheid Leavitt Law as a rare long-period Galactic Cepheid. Understanding the properties of this star will also constrain the physics and evolution of massive (M>=8M_{sun}_) Cepheids. The challenge, however, is precisely measuring the star's pulsation period and its rate of period change. The former is important for calibrating the Leavitt Law and the latter for stellar evolution modeling. In this work, we combine previous time-series observations spanning more than a century with new observations to remeasure the pulsation period and compute the rate of period change. We compare our new rate of period change with stellar evolution models to measure the properties of l Car, but find models and observations are, at best, marginally consistent. The results imply that l Car does not have significantly enhanced mass-loss rates like that measured for {delta} Cephei. We find that the mass of l Car is about 8-10M_{sun}_. We present Hubble Space Telescope Cosmic Origins Spectrograph observations that also differ from measurements for {delta} Cep and {beta} Dor. These measurements further add to the challenge of understanding the physics of Cepheids, but do hint at the possible relation between enhanced mass-loss and ultraviolet emission, perhaps both due to the strength of shocks propagating in the atmospheres of Cepheids.2016ApJ...824....1Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/824/1CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)II/285 : Photoelectric observations of Cepheids in UBV(RI)c (Berdnikov, 2008)II/224 : Catalogue of Stellar Diameters (CADARS) (Pasinetti-Fracassini+ 2001)J/MNRAS/455/4231 : Coralie radial velocities for l Car (Anderson+, 2016)J/A+A/584/A80 : Pulsation model for delta Cep and eta Aql (Merand+, 2015)J/MNRAS/446/4008 : RT Aur and SZ tau UBV light curves (Evans+, 2015)J/AN/336/70 : Veloc. & proper motions of Galactic Cepheids (Mel'nik+, 2015)J/A+A/566/L10 : Cepheid radial velocity amplitude modulations (Anderson, 2014)J/A+A/566/A37 : Iron abundances for 42 Galactic Cepheids (Genovali+, 2014)J/A+A/550/A70 : Galactic & MC Cepheids distance (Groenewegen, 2013)J/ApJ/759/146 : Spitzer/IRAC photom. for 37 Galactic Cepheids (Monson+, 2012)J/MNRAS/420/1590 : Abundances of classical Cepheids (Acharova+, 2012)J/AJ/142/51 : Galactic Cepheids abundance variations (Luck+, 2011)J/MNRAS/410/190 : Young runaway stars within 3kpc (Tetzlaff+, 2011)J/ApJS/190/203 : 3.6 years of DIRBE NIR stellar light curves (Price+, 2010)J/A+A/504/959 : Amplitudes of single-mode Cepheids (Klagyivik+, 2009)J/A+A/502/951 : HARPS observations of nine galactic Cepheids (Nardetto+, 2009)J/AcA/58/313 : LMC Cepheids in OGLE and MACHO data (Poleski+, 2008)J/A+A/476/307 : Period variations in galactic RRab stars (Le Borgne+, 2007)J/A+A/453/309 : HARPS observations of nine galactic Cepheids (Nardetto+, 2006)J/MNRAS/362/1167 : Radial velocities of 14 southern Cepheids (Petterson+, 2005)J/A+A/428/587 : Cepheids BVRIJHK dereddened magnitudes (Kervella+, 2004)J/ApJS/154/673 : COBE DIRBE Point Source Catalog (Smith+, 2004)J/A+AS/143/211 : Galactic Cepheids BVRI photometry (Berdnikov+, 2000)http://www.aavso.org/ : American Association of Variable Star Observers pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/824/1https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/824/1http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/824/1https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/824/1https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/824/1http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/824/1GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/824/1/table1Published and new timing data for l CarrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian Date of maximumdtime.epochdoubleEpoch[-932/534] Epoch numbermeta.id;meta.mainint(O-C)[-8.7/8.3] Residualdstat.fit.residualfloatWeight[0.5/5] Weighting valuestat.weightfloatRefReference (Author and year) (1)meta.ref;pos.framecharBibCodeBibcode for Ref if availablemeta.bib.bibcodechar