J/A+A/622/A45ivo://CDS.VizieR/J/A+A/622/A45doi:10.26093/cds/vizier.36220045CDSIijima T.Naito H.Narusawa S.2020-01-17T10:56:37Z2019-01-24T12:39:05ZCDS support team

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

cds-question@unistra.freclipsing-binary-starsvisible-astronomyspectroscopyCH Cyg is one of the most studied symbiotic stars. Its properties, however, are still not well known. Two main periods, about 15 years and 750-days, are known in the photometric and spectroscopic variations, and two models are proposed for these origins. One is a binary system with an orbital period of 15 years consisting of a hot component and pulsating red giant with a 750-day period. The other is a triple system consisting of an inner symbiotic binary with an orbital period of about 750-days and third component with an orbital period of 15 years. Several active stages have been observed since the 1970s during which the object brightened up by {Delta}U=3-5mag and prominent emission lines appeared. Large mass outflows were observed at some active stages. The spectral variation of CH Cyg has been monitored at Asiago Observatories to understand the problems mentioned above. We have analysed spectra obtained in the time period from 1995 to 2004 which covers an active stage during the years 1998-2000. High- and low-resolution optical spectra obtained at the Asiago Observatories are used. Narrow absorption lines of FeI, CrI, TiI, and so on appeared in 1998 at an early phase of the active stage. These lines are clearly distinguished from those of the M-type giant and are typically found on the spectrum of early A-type dwarfs. They were redshifted by about 30km/s, with respect to the absorption lines of the M-type giant. Assuming that their radial velocities represent the orbital motion of the hot component, its semi-amplitude is estimated to be 37.0+/60.5km/s.2019A&A...622A..45Ihttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/622/A45CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/311/484 : CH Cyg 1991-1995 UBV-JHKLM photometry (Munari+, 1996)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/622/A45https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/622/A45http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/622/A45https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/622/A45https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/622/A45http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/622/A45GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/622/A45/list (*List of spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/622/A45/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/622/A45/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/622/A45/list?GETtext/xml+votable180.050000true291.137791750.24141670.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/622/A456/15135 25789https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/622/A45?format=asciiOpticaldefaultJ/A+A/622/A45/list*List of spectraExpTimeExposure timestime.duration;obs.exposureintInstInstrument (1)meta.id;instrcharObsObservation datestime.epoch;obsnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintNoSpectrum identification numbermeta.id;meta.mainintblambdaLower value of wavelength interval0.1nmem.wlfloatBlambdaUpper value of wavelength interval0.1nmem.wlfloatdlambdaSpectral resolution0.1nmspect.resolutiondoubleJDJulian date (JD-2450000)dtime.epochdoublesizeSize of FITS fileKibytephys.size;meta.fitscharspShow the spectrummeta.ref.urlcharFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS file and commentsmeta.title;meta.fitscharAssocDataAssociated Data web pagemeta.ref.urlchar