The inner disk of RY Tau: evidence of stellar occultation by the disk atmosphere at the sublimation rim from K-band continuum interferometry. (arXiv:2005.06932v1 [astro-ph.SR])

The inner disk of RY Tau: evidence of stellar occultation by the disk atmosphere at the sublimation rim from K-band continuum interferometry. (arXiv:2005.06932v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Davies_C/0/1/0/all/0/1">Claire L. Davies</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kraus_S/0/1/0/all/0/1">Stefan Kraus</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Harries_T/0/1/0/all/0/1">Tim J. Harries</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Monnier_J/0/1/0/all/0/1">John D. Monnier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kloppenborg_B/0/1/0/all/0/1">Brian Kloppenborg</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Aarnio_A/0/1/0/all/0/1">Alicia Aarnio</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baron_F/0/1/0/all/0/1">Fabien Baron</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lopez_R/0/1/0/all/0/1">Rebeca Garcia Lopez</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Millan_Gabet_R/0/1/0/all/0/1">Rafael Millan-Gabet</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parks_R/0/1/0/all/0/1">Robert Parks</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pedretti_E/0/1/0/all/0/1">Ettore Pedretti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Perraut_K/0/1/0/all/0/1">Karine Perraut</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sturmann_J/0/1/0/all/0/1">Judit Sturmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sturmann_L/0/1/0/all/0/1">Laszlo Sturmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Brummelaar_T/0/1/0/all/0/1">Theo A. ten Brummelaar</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Touhami_Y/0/1/0/all/0/1">Yamina Touhami</a>

We present models of the inner region of the circumstellar disk of RY Tau
which aim to explain our near-infrared ($K$-band: $2.1,mu$m) interferometric
observations while remaining consistent with the optical to near-infrared
portions of the spectral energy distribution. Our sub-milliarcsecond 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 $0.210pm0.005,$au, assuming a viewing geometry adopted
from millimeter interferometry ($65^{circ}$ inclined with a disk major axis
position angle of $23^{circ}$). This sublimation radius is consistent with
that expected of Silicate grains with a maximum size of $0.36-0.40,mu$m
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 multi-epoch 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.

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