J/ApJ/889/148 V346 Nor IJHKs photometry & IR spectra (Kospal+, 2020)
V346 Nor: the post-outburst life of a peculiar young eruptive star.
Kospal A., Szabo Z.M., Abraham P., Kraus S., Takami M., Lucas P.W.,
Contreras Pena C., Udalski A.
<Astrophys. J., 889, 148 (2020)>
=2020ApJ...889..148K 2020ApJ...889..148K
ADC_Keywords: Stars, variable; Photometry, infrared; Spectra, infrared; Optical
Keywords: Star formation ; Circumstellar matter ; Infrared astronomy
Abstract:
FU 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.
Description:
We monitored V346 Nor with the SMARTS 1.3m telescope using the ANDICAM
instrument at Cerro Tololo (Chile) between 2016 June 6 and 2019 July 9
with an approximately monthly cadence. On each observing night we
typically obtained five images in the I band, and 5-10 images in the
J, H, and Ks bands.
We could identify V346 Nor in the archive of the Optical Gravitational
Lensing Experiment (OGLE; Udalski+ 2015AcA....65....1U 2015AcA....65....1U) under the name
gd1112.05.9732. We collected all photometric observations obtained
since 2010 in the IC band with the 1.3m Warsaw Telescope at Las
Campanas Observatory in Chile.
V346 Nor was covered as part of two ESO public near-infrared surveys:
the VISTA Variables in the Via Lactea survey (VVV) and its extension
VVVx. Both surveys used the VISTA 4.1m telescope at Paranal
Observatory in Chile and the VIRCAM near-infrared camera. We
downloaded all VIRCAM images that included V346 Nor.
See Section 2.1.
We took spectra of V346 Nor on 2015 June 20, July 12, and July 16
using the XSHOOTER echelle spectrograph on ESO's Very Large Telescope
(VLT) (095.C-0765, PI: S. Kraus). We used the 1.0", 0.9", and 0.4"
wide slits, providing 5400, 8900, and 11600 spectral resolution in the
UVB (0.30-0.56um), VIS (0.53-1.02um), and near-infrared (0.99-2.48um)
arms, respectively. See Section 2.2.
We obtained an N-band spectrum of V346 Nor using VISIR on the VLT
(095.C-0765, PI: S. Kraus). The observations were performed on 2016
February 29 with an exposure time of 2300s, and a slit size of 0.4",
which provided a spectral resolution of R∼350. See Section 2.3.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
16 32 32.19 -44 55 30.7 V346 Nor = V* V346 Nor
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 75 164 Optical and near-infrared photometry of V346 Nor
fig4.dat 30 61563 Average VLT/XSHOOTER spectrum of V346 Nor
observed in 2015 June-July
fig5.dat 27 1006 VLT/VISIR N-band spectrum of V346 Nor, obtained
in the post-outburst phase on 2016 February 29
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See also:
B/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)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 "Y:M:D" Date Date of observation (UT)
13- 19 F7.2 d JD [6438.27/8734.06] Julian Date; JD-2450000.5
21 A1 --- l_Imag Limit flag on Imag
23- 27 F5.2 mag Imag [17.94/20.94]? I band magnitude
29- 32 F4.2 mag e_Imag [0.03/0.55]? Uncertainty on the Imag
34- 38 F5.2 mag Jmag [14.03/15.17]? J-band magnitude
40- 43 F4.2 mag e_Jmag [0.01/0.05]? Uncertainty on the Jmag
45- 49 F5.2 mag Hmag [11.41/12.87]? H-band magnitude
51- 54 F4.2 mag e_Hmag [0.01/0.02]? Uncertainty on the Hmag
56- 61 F6.3 mag Ksmag [8.47/10.79]? Ks-band magnitude
63- 66 F4.2 mag e_Ksmag [0.01/0.13]? Uncertainty on the Ksmag
68- 73 A6 --- Inst Instrument
75 A1 --- n_Inst [a] a=From Kospal+ 2017A&A...597L..10K 2017A&A...597L..10K
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Byte-by-byte Description of file: fig4.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- Arm VLT/XSHOOTER arm identifier (1)
5- 14 F10.8 um lambda [0.3/2.48] Wavelength
16- 30 E15.8 cW/m2/nm Flux [-1.93e-13/1.86e-13] Flux density;
in erg/s/cm2/Å units
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Note (1): Arm as follows:
UVB = 0.3-0.56um (12497 occurrences)
VIS = 0.53-1.02um (24317 occurrences)
NIR = 0.99-2.48um (24749 occurrences)
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Byte-by-byte Description of file: fig5.dat
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Bytes Format Units Label Explanations
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1- 11 F11.8 um lambda [6.7/14] Wavelength
13- 27 E15.8 Jy Flux [-1866/37] Flux density
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Jul-2021