J/A+A/402/745ivo://CDS.VizieR/J/A+A/402/745doi:10.26093/cds/vizier.34020745CDSDuemmler R.Doucet C.Formanek F.Ilyin I.Tuominen I.2017-06-26T11:50:47Z2003-06-28T22:52:33ZCDS support team

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

cds-question@unistra.frspectroscopic-binary-starsradial-velocityER Vul is an eclipsing binary consisting of two solar type stars in a very close orbit with a period of 0.7d. Accordingly, the two stars rotate very fast, leading to a blending of many spectral features at all phases. Therefore, measuring the radial velocity curve without systematic errors is not trivial. Here, we use a two-dimensional cross-correlation method applied to 137 high quality spectra, collected over 3 years, in order to obtain the radial velocity curve and determine the orbital and some physical parameters of the system from it. Primarily, we improve the binary period to 0.69809458d+/-0.00000014d, and find that the two amplitudes are slightly smaller than those measured by others, while the mass ratio is still similar. While at least the primary almost fills its Roche lobe, the system is still detached, i.e. not yet a fully fledged W UMa-system. The behaviour of the CaII IRT line at 8662{AA} confirms that the secondary is the more active component, and that the chromospheric emission is not symmetrically distributed over the surfaces of either star.2003A&A...402..745Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/402/745CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/AN/323/31 : UBVR light curves of ER Vul and RT And (Ekmekci+, 2002)J/A+A/415/289 : UBVRI light curves of ER Vul (Harmanec+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/402/745https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/402/745http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/402/745https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/402/745https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/402/745http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/402/745GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/402/745/table1The measured radial velocities and their errorsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian date of mid-exposuredtime.epochdoubleRV1Radial velocity of the primarykm/sphys.veloc;pos.heliocentricdoublee_RV1Standard deviation of RV1km/sstat.errordoubleRV2Radial velocity of the secondarykm/sphys.veloc;pos.heliocentricdoublee_RV2Standard deviation of RV2km/sstat.errordoubleRVCa1? Radial velocity of the Ca II line 8662{AA} for the primarykm/sphys.veloc;pos.heliocentricdoublenullablee_RVCa1? standard deviation of RVCa1km/sstat.errordoublenullableRVCa2? Radial velocity of the Ca II line 8662{AA} for the secondarykm/sphys.veloc;pos.heliocentricdoublenullablee_RVCa2? standard deviation of RVCa2km/sstat.errordoublenullable