J/A+A/644/A49ivo://CDS.VizieR/J/A+A/644/A49doi:10.26093/cds/vizier.36440049CDSMerc J.Mikolajewska J.Gromadzki M.Galan C.Ilkiewicz K.Skowron J.,Wyrzykowski L.Hodgkin S.T.Rybicki K.A.Zielinski P.Kruszynska K.,Godunova V.Simon A.Reshetnyk V.Lewis F.Kolb U.Morrell M.,Norton A.J.Awiphan S.Poshyachinda S.Reichart D.E.Greet M.,Kolgjini J.2021-09-09T09:38:51Z2020-12-01T08:17:20ZCDS support team

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

cds-question@unistra.frcataclysmic-variable-starsphotometryvisible-astronomyradial-velocityspectroscopyBesides the astrometric mission of the Gaia satellite, its repeated and high-precision measurements also serve as an all-sky photometric transient survey. The sudden brightenings of the sources are published as Gaia Photometric Science Alerts and are made publicly available, allowing the community to photometrically and spectroscopically follow up on the object. The goal of this paper is to analyze the nature and derive the basic parameters of Gaia18aen, a transient detected at the beginning of 2018. This object coincides with the position of the emission-line star WRAY 15-136. The brightening was classified as a "nova?" on the basis of a subsequent spectroscopic observation. We analyzed two spectra of Gaia18aen and collected the available photometry of the object covering the brightenings in 2018 and also the preceding and following periods of quiescence. Based on this observational data, we derived the parameters of Gaia18aen and discussed the nature of the object. Gaia18aen is the first symbiotic star discovered by Gaia satellite. The system is an S-type symbiotic star and consists of an M giant of a slightly super-solar metallicity, where Teff~3500K, a radius of ~230R_{sun}_, and a high luminosity L~7400L_{sun}_. The hot component is a hot white dwarf. We tentatively determined the orbital period of the system 487d. The main outburst of Gaia18aen in 2018 was accompanied by a decrease in the temperature of the hot component. The first phase of the outburst was characterized by the high luminosity L~27000L_{sun}_, which remained constant for about three weeks after the optical maximum, later followed by the gradual decline of luminosity and increase of temperature. Several re-brightenings have been detected on the timescales of hundreds of days.2020A&A...644A..49Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/644/A49CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/644/A49https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/644/A49http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/644/A49https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/644/A49https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/644/A49http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/644/A49GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/644/A49/tablea1Photometrical observations of Gaia18aenrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDDate of observation (JD-240000)dtime.epochdoublemagMagnitude in Filtermagphot.magfloate_mag? Magnitude error in Filtermagstat.error;phot.magfloatnullableFilter[G BVI co gri] Filter, in which the particular observation was obtainedmeta.id;instr.filtercharSourceSource of the data (1)meta.id;instrcharJ/A+A/644/A49/table3Positions, radial velocities, and fluxes of identified emission lines in the VLT/X-Shooter spectrum of Gaia18aen obtained on March 22, 2018.recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaMeasured wavelength of line in the spectrum0.1nmem.wl;spect.linedoubleLineIdentification of the linemeta.id;spect.linecharlambdaRefReference wavelength of the line0.1nmmeta.ref;em.wl;spect.linecharFlux? Measured flux in the line (in 10^-14^erg/cm^2^/s) (1)1e-17W.m**-2phot.flux;spect.linefloatnullablen_Flux[s] s for saturatedmeta.notecharRVRadial velocity of the line, heliocentric velocity correctedkm/sspect.dopplerVeloc;spect.linefloat