Title: Thermophysical characteristics of the large main-belt asteroid (349) Dembowska,
Abstract: (349) Dembowska, a large, bright main-belt asteroid, has a fast rotation and
oblique spin axis. It may have experienced partial melting and differentiation.
We constrain Dembowska's thermophysical properties, e.g., thermal inertia,
roughness fraction, geometric albedo and effective diameter within 3$\sigma$
uncertainty of $\Gamma=20^{+12}_{-7}\rm~Jm^{-2}s^{-0.5}K^{-1}$, $f_{\rm
r}=0.25^{+0.60}_{-0.25}$, $p_{\rm v}=0.309^{+0.026}_{-0.038}$, and $D_{\rm
eff}=155.8^{+7.5}_{-6.2}\rm~km$, by utilizing the Advanced Thermophysical Model
(ATPM) to analyse four sets of thermal infrared data obtained by IRAS, AKARI,
WISE and Subaru/COMICS at different epochs. In addition, by modeling the
thermal lightcurve observed by WISE, we obtain the rotational phases of each
dataset. These rotationally resolved data do not reveal significant variations
of thermal inertia and roughness across the surface, indicating the surface of
Dembowska should be covered by a dusty regolith layer with few rocks or
boulders. Besides, the low thermal inertia of Dembowska show no significant
difference with other asteroids larger than 100 km, indicating the dynamical
lives of these large asteroids are long enough to make the surface to have
sufficiently low thermal inertia. Furthermore, based on the derived surface
thermophysical properties, as well as the known orbital and rotational
parameters, we can simulate Dembowska's surface and subsurface temperature
throughout its orbital period. The surface temperature varies from $\sim40$ K
to $\sim220$ K, showing significant seasonal variation, whereas the subsurface
temperature achieves equilibrium temperature about $120\sim160$ K below
$30\sim50$ cm depth.