J/AJ/159/121ivo://CDS.VizieR/J/AJ/159/121doi:10.26093/cds/vizier.51590121CDSEvans N.R.Pillitteri I.Molnar L.Szabados L.Plachy E.Szabo R.,Engle S.Guinan E.Wolk S.Gunther H.M.Neilson H.Marengo M.,Matthews L.D.Moschou S.Drake J.J.Kashyap V.Kervella P.Tordai T.,Somogyi P.Burki G.2021-06-10T07:19:36Z2020-05-20T07:50:46ZCDS support team

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

cds-question@unistra.frx-ray-sourcesvariable-starsvisible-astronomyWide-band photometryccd-photometryradial-velocityV473Lyr is a classical Cepheid that is unique in having substantial amplitude variations with a period of approximately 3.3yr, thought to be similar to the Blazhko variations in RR Lyrae stars. We obtained an X-ray Multi-Mirror Mission (XMM)-Newton observation of this star to follow up a previous detection in X-rays. Rather than the X-ray burst and rapid decline near maximum radius seen in {delta}Cephei itself, the X-ray flux in V473Lyr remained constant for a third of the pulsation cycle covered by the observation. Thus the X-rays are probably not produced by the changes around the pulsation cycle. The X-ray spectrum is soft (kT=0.6keV), with X-ray properties consistent with a young low-mass companion. Previously there was no evidence of a companion in radial velocities or in Gaia and Hipparcos proper motions. While this rules out companions that are very close or very distant, a binary companion at a separation between 30 and 300au is possible. This is an example of an X-ray observation revealing evidence of a low-mass companion, which is important in completing the mass ratio statistics of binary Cepheids. Furthermore, the detection of a young X-ray bright companion is a further indication that the Cepheid (primary) is a Population I star, even though its pulsation behavior differs from other classical Cepheids.2020AJ....159..121Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/159/121CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/xmm : XMM-Newton Observation Log (2002-2014)I/345 : Gaia DR2 (Gaia Collaboration, 2018)IX/55 : XMM-Newton Serendipitous Source Catalogue 3XMM-DR8 (XMM-SSC, 2018)J/MNRAS/362/1167 : Radial velocities of 14 southern Cepheids (Petterson+, 2005)J/AJ/136/1770 : VI light curves of NGC 247 Cepheids (Garcia-Varela+, 2008)J/AJ/137/4598 : VR light curve of ASAS-North Cepheids (Schmidt+, 2009)J/ApJ/694/1237 : BVRI light curves of NGC 247 Cepheids (Madore+, 2009)J/PAZh/35/44 : BV light curves of 33 ASAS-3 Cepheids (Berdnikov+, 2009)J/AcA/60/17 : VI light curves of SMC classical Cepheids (Soszynski+, 2010)J/A+A/534/A94 : Milky Way Cepheids radial velocities (Storm+, 2011)J/A+A/534/A95 : LMC Cepheids radial velocities (Storm+, 2011)J/AcA/61/285 : VI light curves of Galactic Bulge Cepheids (Soszynski+,2011)J/AJ/145/143 : XMM observations of {alpha} Per (Pillitteri+, 2013)J/MNRAS/434/870 : Radial velocity curves of 3 Cepheids (Szabados+, 2013)J/PAZh/40/147 : BVIc light curves of 57 Cepheids (Berdnikov+, 2014)J/AJ/150/13 : Cepheid Radial Velocities (CRaV) project (Evans+, 2015)J/ApJS/226/18 : 5yr radial velocity of 19 Cepheids (Anderson+, 2016)J/AcA/68/89 : VI light curves of SMC type II Cepheids (Soszynski+, 2018)J/A+A/622/A164 : Radial velocity curves of 11 Cepheids (Gallenne+, 2019)J/A+A/623/A72 : Binarity of Hipparcos stars Gaia pm anomaly (Kervella+,2019)J/A+A/631/A37 : Classical Cepheids consistent RVs (Borgniet+,2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/159/121https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/159/121http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/159/121https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/159/121https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/159/121http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/159/121GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapX-rayOpticaldefaultJ/AJ/159/121/table2Photometry of V473 LyrrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[58553/58565] Julian Date; JD-2400000dtime.epochdoubleVmag[6.039/6.253] Apparent V band magnitudemagphot.mag;em.opt.Vfloate_Vmag[0.001/0.002] Standard deviation in Vmagmagstat.error;phot.mag;em.opt.VfloatJ/AJ/159/121/table4CORrelation RADial VELocities (CORAVEL) velocities of V473Lyr discussed by Burki (2006JAVSO..35...19B)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[43286/51130] Julian Date; JD-2400000dtime.epochdoubleRV[-33.8/5.7] Radial velocitykm/sphys.veloc;pos.heliocentricfloate_RV[0.2/1.6] Standard deviation in RVkm/sstat.errorfloatJ/AJ/159/121/table3Radial Velocities of V473 Lyr in 2019recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJD[58559/58567] Julian Date; JD-2400000dtime.epochdoubleRV[-17.9/-13.1] Radial velocitykm/sphys.veloc;pos.heliocentricfloate_RV[0.4/0.9] Standard deviation in RVkm/sstat.errorfloat