J/A+A/511/A63 V1118 Ori UBVRIJHK outburst light curves (Audard+, 2010)
A multi-wavelength study of the young star V1118 Orionis in outburst.
Audard M., Stringfellow G.S., Guedel M., Skinner S.L., Walter F.M.,
Guinan E.F., Hamilton R.T., Briggs K.R., Baldovin-Saavedra C.
<Astron. Astrophys. 511, A63 (2010)>
=2010A&A...511A..63A 2010A&A...511A..63A
ADC_Keywords: Stars, variable ; Stars, late-type ; Stars, pre-main sequence ;
X-ray sources ; Photometry, UBVRIJKLMNH ; Accretion
Keywords: accretion, accretion disks - infrared: stars - circumstellar matter -
stars: coronae - stars: pre-main sequence - X-rays: stars
Abstract:
The accretion history of low-mass young stars is not smooth but shows
spikes of accretion that can last from months and years to decades and
centuries. Observations of young stars in outbursts can help us
understand the temporal evolution of accreting stars and the interplay
between the accretion disk and the stellar magnetosphere. The young
late-type star V1118 Orionis was in outburst from 2005 to 2006. We
followed the outburst with optical and near-infrared photometry. The
X-ray emission was further probed with observations taken with
XMM-Newton and Chandra during and after the outburst. In addition, we
obtained mid-infrared photometry and spectroscopy with Spitzer at the
peak of the outburst and in the post-outburst phase. The spectral
energy distribution of V1118 Ori varied significantly over the course
of the outburst. The optical flux showed the largest variations, most
likely caused by enhanced emission by a hot spot. The hot spot
dominated the optical and near-infrared emission at the peak of the
outburst, while the disk emission dominated in the mid-infrared. The
emission silicate feature in V1118 Ori is flat and does not vary in
shape, but was slightly brighter at the peak of the outburst compared
to the post-outburst spectrum. The X-ray flux correlated with the
optical and infrared fluxes, indicating that accretion affected the
magnetically active corona and the stellar magnetosphere. The thermal
structure of the corona was variable with some indication of a cooling
of the coronal temperature in the early phase of the outburst with a
gradual return to normal values.
Color-color diagrams in the optical and infrared showed variations
during the outburst, with no obvious signature of reddening caused by
circumstellar matter. Using Monte-Carlo realizations of
star+disk+hotspot models to fit the spectral energy distributions in
"quiescence" and at the peak of the outburst, we determined that the
mass accretion rate varied from about 2.5x10-7M☉/yr to
1.0x10-6M☉/yr; in addition, the fractional area of the hotspot
increased significantly. The multi-wavelength study of the V1118 Ori
outburst helped us to understand the variations in spectral energy
distributions and demonstrated the interplay between the disk and the
stellar magnetosphere in a young, strongly accreting star.
Description:
Optical and near-infrared photometry taken by the ANDICAM imager on
the SMARTS/CTIO 1.3m telescope, and by the Villanova telescope as part
of the multi-wavelength campaign to observe the young EXor star V1118
Ori in outburst. The catalogues give magnitudes as a function of the
modified Julian date.
Objects:
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RA (2000) DE Designation(s)
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05 34 44.7 -05 33 42 V1118 Ori = V* V1118 Ori
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea2.dat 93 155 SMARTS UBVRIJHK photometry
tablea3.dat 38 35 Villanova VRI photometry
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 5 I5 d MJD Modified Julian Date (JD-2400000.5)
7- 11 F5.2 mag Umag ? SMARTS Johnson U-band magnitude
13- 16 F4.2 mag e_Umag ? SMARTS Johnson U-band magnitude uncertainty
18- 22 F5.2 mag Bmag ? SMARTS Johnson B-band magnitude
24- 27 F4.2 mag e_Bmag ? SMARTS Johnson B-band magnitude uncertainty
29- 33 F5.2 mag Vmag ? SMARTS Johnson V-band magnitude
35- 38 F4.2 mag e_Vmag ? SMARTS Johnson V-band magnitude uncertainty
40- 44 F5.2 mag Rmag ? SMARTS Cousins R-band magnitude
46- 49 F4.2 mag e_Rmag ? SMARTS Cousins R-band magnitude uncertainty
51- 55 F5.2 mag Imag ? SMARTS Cousins I-band magnitude
57- 60 F4.2 mag e_Imag ? SMARTS Cousins I-band magnitude uncertainty
62- 66 F5.2 mag Jmag ? SMARTS J-band magnitude
68- 71 F4.2 mag e_Jmag ? SMARTS J-band magnitude uncertainty
73- 77 F5.2 mag Hmag ? SMARTS H-band magnitude
79- 82 F4.2 mag e_Hmag ? SMARTS H-band magnitude uncertainty
84- 88 F5.2 mag Kmag ? SMARTS K-band magnitude
90- 93 F4.2 mag e_Kmag ? SMARTS K-band magnitude uncertainty
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 5 I5 d MJD Modified Julian Date (JD-2400000.5)
7- 11 F5.2 mag Vmag Villanova Bessel V-band magnitude
13- 16 F4.2 mag e_Vmag Villanova Bessel V-band magnitude uncertainty
18- 22 F5.2 mag Rmag Villanova Bessel R-band magnitude
24- 27 F4.2 mag e_Rmag Villanova Bessel R-band magnitude uncertainty
29- 33 F5.2 mag Imag Villanova Bessel I-band magnitude
35- 38 F4.2 mag e_Imag Villanova Bessel I-band magnitude uncertainty
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Acknowledgements:
Marc Audard, Marc.Audard(at)unige.ch
(End) M. Audard [ISDC & Obs. Geneve, Switzerland], P. Vannier [CDS] 29-Dec-2009