J/A+A/646/A102 FU Ori multi-band interferometric observations (Labdon+, 2021)
Viscous heating in the disk of the outbursting star FU Orionis.
Labdon A., Kraus S., Davies C.L., Kreplin A., Monnier J.D.,
Le Bouquin J.-B., Anugu N., ten Brummelaar T., Setterholm B., Gardner T.,
Ennis J., Lanthermann C., Schaefer G., Laws A.
<Astron. Astrophys. 646, A102 (2021)>
=2021A&A...646A.102L 2021A&A...646A.102L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; YSOs ; Interferometry ; Infrared
Keywords: techniques: interferometric - accretion, accretion disks -
protoplanetary disks
Abstract:
FU Orionis is the archetypal FUor star, a subclass of young stellar
object (YSO) that undergo rapid brightening events, often gaining 4-6
magnitudes on timescales of days. This brightening is often associated
with a massive increase in accretion; one of the most ubiquitous
processes in astrophysics from planets and stars to super-massive
black holes. We present multi-band interferometric observations of the
FU Ori circumstellar environment, including the first J-band
interferometric observations of a YSO.
We investigate the morphology and temperature gradient of the
inner-most regions of the accretion disk around FU Orionis. We aim to
characterise the heating mechanisms of the disk and comment on
potential outburst triggering processes. Methods. Recent upgrades to
the MIRC-X instrument at the CHARA array allowed the first dual-band J
and H observations of YSOs. Using baselines up to 331m, we present
high angular resolution data of a YSO covering the near-infrared bands
J, H, and K. The unprecedented spectral range of the data allows us to
apply temperature gradient models to the innermost regions of FU Ori.
We spatially resolve the innermost astronomical unit of the disk and
determine the exponent of the temperature gradient of the inner disk
to T∝r-0.74±0.02. This agrees with theoretical work that
predicts T∝r-0.75 for actively accreting, steady state disks, a
value only obtainable through viscous heating within the disk. We find
a disk which extends down to the stellar surface at 0.015±0.007au
where the temperature is found to be 5800±700K indicating boundary
layer accretion. We find a disk inclined at 32±4° with a
minor-axis position angle of 34±11°.
Description:
MIRCX Data of FU Ori.
Objects:
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RA (2000) DE Designation(s)
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05 45 22.37 +09 04 12.3 FU Ori = BD+09 5427
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 103 14 List of OI-FITS files
fits/* . 14 Individual OI-FITS files
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Simbad right ascension (J2000)
4- 5 I2 min RAm Simbad right ascension (J2000)
7- 11 F5.2 s RAs Simbad right ascension (J2000)
12 A1 --- DE- Simbad declination sign (J2000)
13- 14 I2 deg DEd Simbad declination (J2000)
16- 17 I2 arcmin DEm Simbad declination (J2000)
19- 22 F4.1 arcsec DEs Simbad declination (J2000)
24- 33 A10 "date" Obs.date Observation date
35- 36 I2 Kibyte size Size of OI-FITS file
38- 64 A27 --- FileName Name of OI-FITS file, in subdirectory fits
66-103 A38 --- Title Title of the OI-FITS file
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Acknowledgements:
Aaron Labdon, al612(at)exeter.ac.uk
(End) Patricia Vannier [CDS] 10-Feb-2021