J/A+A/625/L8ivo://CDS.VizieR/J/A+A/625/L8doi:10.26093/cds/vizier.36259008CDSPastorello A.Chen T.-W.Cai Y.-Z.Morales-Garoffolo A.Cano Z.,Mason E.Barsukova E.A.Benetti S.Berton M.Bose S.Bufano F.,Callis E.Cannizzaro G.Cartier R.Chen P.Dong S.Dyrbye S.,Elias-Rosa N.Floers A.Fraser M.Geier S.Goranskij V.P.Kann D.A.,Kuncarayakti H.Onori F.Reguitti A.Reynolds T.Losada I.R.,Sagues Carracedo A.Schweyer T.Smartt S.J.Tatarnikov A.M.,Valeev A.F.Vogl C.Wevers T.de Ugarte Postigo A.Izzo L.,Inserra C.Kankare E.Maguire K.Smith K.W.Stalder B.Tartaglia L.,Thoene C.C.Valerin G.Young D.R.2019-06-06T05:36:32Z2019-05-17T12:20:35ZCDS support team

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

cds-question@unistra.frnovaemultiple-starsccd-photometryWe present the results of our photometric and spectroscopic follow-up of the intermediate-luminosity optical transient AT 2017jfs. At peak, the object reaches an absolute magnitude of Mg=-15.46+/-0.15mag and a bolometric luminosity of 5.5x10^41^erg/s. Its light curve has the double-peak shape typical of luminous red novae (LRNe), with a narrow first peak bright in the blue bands, while the second peak is longer-lasting and more luminous in the red and near-infrared (NIR) bands. During the first peak, the spectrum shows a blue continuum with narrow emission lines of H and FeII. During the second peak, the spectrum becomes cooler, resembling that of a K-type star, and the emission lines are replaced by a forest of narrow lines in absorption. About 5 months later, while the optical light curves are characterized by a fast linear decline, the NIR ones show a moderate rebrightening, observed until the transient disappears in solar conjunction. At these late epochs, the spectrum becomes reminiscent of that of M-type stars, with prominent molecular absorption bands. The late-time properties suggest the formation of some dust in the expanding common envelope or an IR echo from foreground pre-existing dust. We propose that the object is a common-envelope transient, possibly the outcome of a merging event in a massive binary, similar to NGC4490-2011OT1.2019A&A...625L...8Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/625/L8CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/625/L8https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/625/L8http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/625/L8https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/625/L8https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/625/L8http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/625/L8GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap7.952274030004205e-20 5.046557045242342e-19defaultJ/A+A/625/L8/tablea1Broadband photometry of AT 2017jfsMJDModified Julian Datetime.epochdoublel_gmagDetection limit symbol on gmagmeta.code.errorcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of the observation (yyyymmdd)time.epochintl_BmagDetection limit symbol on Bmagmeta.code.errorcharBmag? Johnson-Bessell B-band magnitude (Vega)magphot.mag;em.opt.Bfloatnullablee_Bmag? B-band magnitude errormagstat.error;phot.mag;em.opt.Bfloatnullablel_VmagDetection limit symbol on Vmagmeta.code.errorcharVmag? Johnson-Bessell V-band magnitude (Vega)magphot.mag;em.opt.Vfloatnullablee_Vmag? V-band magnitude errormagstat.error;phot.mag;em.opt.Vfloatnullablel_umagDetection limit symbol on umagmeta.code.errorcharumag? Sloan u-band magnitude (AB)magphot.mag;em.opt.Ufloatnullablee_umag? u-band magnitude errormagstat.error;phot.mag;em.opt.Ufloatnullablegmag? Sloan g-band magnitude (AB)magphot.mag;em.opt.Bfloatnullablee_gmag? g-band magnitude errormagstat.error;phot.mag;em.opt.Bfloatnullablel_rmagDetection limit symbol on rmagmeta.code.errorcharrmag? Sloan r-band magnitude (AB)magphot.mag;em.opt.Rfloatnullablee_rmag? r-band magnitude errormagstat.error;phot.mag;em.opt.Rfloatnullablel_imagDetection limit symbol on imagmeta.code.errorcharimag? Sloan i-band magnitude (AB)magphot.mag;em.opt.Ifloatnullablee_imag? i-band magnitude errormagstat.error;phot.mag;em.opt.Ifloatnullablel_zmagDetection limit symbol on zmagmeta.code.errorcharzmag? Sloan z-band magnitude (AB)magphot.mag;em.opt.Ifloatnullablee_zmag? z-band magnitude errormagstat.error;phot.mag;em.opt.Ifloatnullablel_JmagDetection limit symbol on Jmagmeta.code.errorcharJmag? J-band magnitude (Vega)magphot.mag;em.IR.Jfloatnullablee_Jmag? J-band magnitude errormagstat.error;phot.mag;em.IR.Jfloatnullablel_HmagDetection limit symbol on Hmagmeta.code.errorcharHmag? H-band magnitude (Vega)magphot.mag;em.IR.Hfloatnullablee_Hmag? H-band magnitude errormagstat.error;phot.mag;em.IR.Hfloatnullablel_KmagDetection limit symbol on Kmagmeta.code.errorcharKmag? K-band magnitude (Vega)magphot.mag;em.IR.Kfloatnullablee_Kmag? K-band magnitude errormagstat.error;phot.mag;em.IR.KfloatnullableInstrInstrumental configuration code (1)meta.codeint