J/ApJ/889/148ivo://CDS.VizieR/J/ApJ/889/148doi:10.26093/cds/vizier.18890148CDSKospal A.Szabo Z.M.Abraham P.Kraus S.Takami M.Lucas P.W.,Contreras Pena C.Udalski A.2022-01-17T11:51:03Z2021-08-06T13:25:48ZCDS support team

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

cds-question@unistra.frvariable-starsinfrared-photometryinfrared-astronomyspectroscopyvisible-astronomyFU Orionis-type objects (FUors) are young low-mass stars undergoing powerful accretion outbursts. The increased accretion is often accompanied by collimated jets and energetic, large-scale molecular outflows. The extra heating during the outburst may also induce detectable geometrical, chemical, and mineralogical changes in the circumstellar material, affecting possible planet formation around these objects. V346 Nor is a southern FUor with peculiar spectral characteristics. Decades after the beginning of its outburst, it unexpectedly underwent a fading event around 2010 due to a decrease in the mass accretion rate onto the star by at least two orders of magnitude. Here we present optical and near-infrared photometry and spectroscopy obtained after the minimum. Our light curves show a gradual re-brightening of V346 Nor, with its Ks-band brightness only 1.5mag below the outburst brightness level. Our Very Large Telescope (VLT)/XSHOOTER spectroscopic observations display several strong forbidden emission lines toward the source from various metals and molecular hydrogen, suggesting the launch of a new jet. Our N-band spectrum obtained with VLT/VISIR outlines a deeper silicate absorption feature than before, indicating that the geometry of the circumstellar medium has changed in the post-outburst period compared to peak brightness.2020ApJ...889..148Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/889/148CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)B/eso : ESO Science Archive Catalog (ESO, 1991-2021)II/337 : VISTA Variables in the Via Lactea Survey DR1 (Saito+, 2012)II/328 : AllWISE Data Release (Cutri+ 2013)J/A+AS/125/149 : CHIANTI- An Atomic Database For Emission Lines I. (Dere+ 1997)J/A+A/474/891 : 13CO obs. of YSOs in South Gal. plane (Urquhart+, 2007)J/AJ/145/94 : Luminosities of protostars from Spitzer (Dunham+, 2013)J/ApJ/778/116 : V1647 Ori long-term optical & NIR observations (Ninan+, 2013)J/AJ/147/140 : SED of 24 class I & class II FU Orionis stars (Gramajo+, 2014)J/MNRAS/437/1791 : RMS survey: molecular observations (Urquhart+, 2014)J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)J/ApJ/815/4 : V899 Mon long-term monitoring (Ninan+, 2015)J/ApJS/225/15 : IR excess stars from Tycho-2 and AllWISE (Cotten+, 2016)J/A+A/594/A59 : Far-IR lines in YSOs Herschel-PACS (Riviere-Marichalar+, 2016)J/A+A/617/A83 : MIDI atlas of low- and intermediate-mass YSOs (Varga+, 2018)J/A+A/631/A30 : Emission line flux densities for 12 YSOs (Postel+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/889/148https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/889/148http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/889/148https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/889/148https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/889/148http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/889/148GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap7.952274030004205e-20 1.0188844282367877e-19OpticalInfrareddefaultJ/ApJ/889/148/table1Optical and near-infrared photometry of V346 Nore_Imag[0.03/0.55]? Uncertainty on the Imagmagstat.error;phot.magfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation (UT)time.epochnullableJD[6438.27/8734.06] Julian Date; JD-2450000.5dtime.epochfloatl_ImagLimit flag on Imagmeta.code.errorcharImag[17.94/20.94]? I band magnitudemagphot.mag;em.opt.IfloatnullableJmag[14.03/15.17]? J-band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag[0.01/0.05]? Uncertainty on the Jmagmagstat.error;phot.magfloatnullableHmag[11.41/12.87]? H-band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag[0.01/0.02]? Uncertainty on the Hmagmagstat.error;phot.magfloatnullableKsmag[8.47/10.79]? Ks-band magnitudemagphot.mag;em.IR.Kfloatnullablee_Ksmag[0.01/0.13]? Uncertainty on the Ksmagmagstat.error;phot.magfloatnullableInstInstrumentmeta.id;instrcharn_Inst[a] a=From Kospal+ 2017A&A...597L..10Kmeta.notecharJ/ApJ/889/148/fig4Average VLT/XSHOOTER spectrum of V346 Nor observed in 2015 June-JulyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintArmVLT/XSHOOTER arm identifier (1)meta.id;instrcharlambda[0.3/2.48] Wavelengthumem.wldoubleFlux[-1.93e-13/1.86e-13] Flux density; in erg/s/cm^2^/{AA} unitscW.m**-2.nm**-1phot.fluxdoubleJ/ApJ/889/148/fig5VLT/VISIR N-band spectrum of V346 Nor, obtained in the post-outburst phase on 2016 February 29lambda[6.7/14] Wavelengthumem.wldoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFlux[-1866/37] Flux densityJyphot.fluxdouble