The GRAVITY young stellar object survey III. The dusty disk of RY Lup
  We use PIONIER data from the ESO archive and GRAVITY data that were obtained
in June 2017 with the four 8m telescopes. We use a parametric disk model and
the 3D radiative transfer code MCFOST to reproduce the Spectral Energy
Distribution and match the interferometric observations. To match the SED , our
model requires a stellar luminosity of 2.5 Lsun, higher than any previously
determined values. Such a high value is needed to accommodate the circumstellar
extinction caused by the highly inclined disk, which has been neglected in
previous studies. While using an effective temperature of 4800 K determined
through high-resolution spectroscopy, we derive a stellar radius of 2.29 Rsun.
These revised fundamental parameters, when combined with the mass estimates
available , lead to an age of 0.5-2.0 Ma for RY Lup, in better agreement with
the age of the Lupus association than previous determinations. Our disk model
nicely reproduces the interferometric GRAVITY data and is in good agreement
with the PIONIER ones. We derive an inner rim location at 0.12~au from the
central star. This model corresponds to an inclination of the inner disk of
50deg, which is in mild tension with previous determinations of a more inclined
outer disk from SPHERE (70 deg in NIR) and ALMA(67 $\pm$5 deg) images, but
consistent with the inclination determination from the ALMA CO spectra
(55$\pm$5deg). Increasing the inclination of the inner disk to 70 deg leads to
a higher line-of-sight extinction and therefore requires a higher stellar
luminosity of 4.65 Lsun to match the observed flux levels. This luminosity
would translate to a stellar radius of 3.13~Rsun, leading to an age of 2-3~Ma,
and a stellar mass of about 2 Msun, in disagreement with the observed dynamical
mass estimate of 1.3-1.5 Msun. Critically, this high-inclination inner disk
model also fails to reproduce the visibilities observed with GRAVITY.
