The inner disk of RY Tau: evidence of stellar occultation by the disk atmosphere at the sublimation rim from K-band continuum interferometry
Davies, CL; Kraus, S; Harries, TJ; et al.Monnier, JD; Kloppenborg, B; Aarnio, A; Baron, F; Lopez, RG; Millan-Gabet, R; Parks, R; Pedretti, E; Perraut, K; Sturmann, J; Sturmann, L; Brummelaar, TAT; Touhami, Y
Date: 30 June 2020
Journal
Astrophysical Journal
Publisher
IOP Publishing / American Astronomical Society
Publisher DOI
Abstract
We present models of the inner region of the circumstellar disk of RY Tau that aim to explain our near-infrared
(K-band: 2.1 μm) interferometric observations, while remaining consistent with the optical to near-infrared portions
of the spectral energy distribution. Our submilliarcsecond-resolution CHARA Array observations are
supplemented ...
We present models of the inner region of the circumstellar disk of RY Tau that aim to explain our near-infrared
(K-band: 2.1 μm) interferometric observations, while remaining consistent with the optical to near-infrared portions
of the spectral energy distribution. Our submilliarcsecond-resolution CHARA Array observations are
supplemented with shorter baseline, archival data from PTI, KI, and VLTI/GRAVITY and modeled using an
axisymmetric Monte Carlo radiative transfer code. The K-band visibilities are well fit by models incorporating a
central star illuminating a disk with an inner edge shaped by dust sublimation at 0.210 ± 0.005 au, assuming a
viewing geometry adopted from millimeter interferometry (65° inclined with a disk major axis position angle of
23°). This sublimation radius is consistent with that expected of silicate grains with a maximum size of
0.36–0.40 μm contributing to the opacity, and is an order of magnitude further from the star than the theoretical
magnetospheric truncation radius. The visibilities on the longest baselines probed by CHARA indicate that we lack
a clear line of sight to the stellar photosphere. Instead, our analysis shows that the central star is occulted by the
disk surface layers close to the sublimation rim. While we do not see direct evidence of temporal variability in our
multiepoch CHARA observations, we suggest the aperiodic photometric variability of RY Tau is likely related
temporal and/or azimuthal variations in the structure of the disk surface layers.
Physics and Astronomy
Faculty of Environment, Science and Economy
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