dc.contributor.author | Labdon, A | |
dc.contributor.author | Kraus, S | |
dc.contributor.author | Davies, CL | |
dc.contributor.author | Kreplin, A | |
dc.contributor.author | Monnier, JD | |
dc.contributor.author | Bouquin, J-BL | |
dc.contributor.author | Anugu, N | |
dc.contributor.author | Brummelaar, T | |
dc.contributor.author | Setterholm, B | |
dc.contributor.author | Gardener, T | |
dc.contributor.author | Ennis, J | |
dc.contributor.author | Lanthermann, C | |
dc.contributor.author | Schaefer, G | |
dc.contributor.author | Laws, A | |
dc.date.accessioned | 2020-11-25T13:57:11Z | |
dc.date.issued | 2021-02-15 | |
dc.description.abstract | Context. 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 Y SO.
Aims. 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 331 m, 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.
Results. 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 ± 0.007 au where the temperature is found to be 5800 ± 700 K indicating boundary layer accretion. We find a disk inclined at
32 ± 4
◦ with a minor-axis position angle of 34 ± 11◦
.
Conclusions. We demonstrate that J-band interferometric observations of YSOs are feasible with the MIRC-X instrument at CHARA.
The temperature gradient power-law derived for the inner disk is consistent with theoretical predictions for steady-state, optically
thick, viciously heated accretion disks. | en_GB |
dc.description.sponsorship | European Research Council (ERC) | en_GB |
dc.identifier.citation | Vol. 646, article A102 | en_GB |
dc.identifier.doi | 10.1051/0004-6361/202039370 | |
dc.identifier.grantnumber | 639889 | en_GB |
dc.identifier.uri | http://hdl.handle.net/10871/123775 | |
dc.language.iso | en | en_GB |
dc.publisher | EDP Sciences / European Southern Observatory | en_GB |
dc.rights | © ESO 2021 | |
dc.subject | Stars: individual: FU Orionis | en_GB |
dc.subject | Techniques: interferometric | en_GB |
dc.subject | Accretion disks | en_GB |
dc.title | Viscous heating and boundary layer accretion in the disk of outbursting star FU Orionis | en_GB |
dc.type | Article | en_GB |
dc.date.available | 2020-11-25T13:57:11Z | |
dc.identifier.issn | 0004-6361 | |
dc.description | This is the final version. Available from EDP Sciences via the DOI in this record | en_GB |
dc.identifier.eissn | 1432-0746 | |
dc.identifier.journal | Astronomy and Astrophysics | en_GB |
dc.rights.uri | http://www.rioxx.net/licenses/all-rights-reserved | en_GB |
dcterms.dateAccepted | 2020-11-14 | |
rioxxterms.version | VoR | en_GB |
rioxxterms.licenseref.startdate | 2020-11-14 | |
rioxxterms.type | Journal Article/Review | en_GB |
refterms.dateFCD | 2020-11-25T13:54:05Z | |
refterms.versionFCD | AM | |
refterms.dateFOA | 2021-03-12T10:16:56Z | |
refterms.panel | B | en_GB |