  Themis family is one of the largest and oldest asteroid populations in the
main-belt. Water-ice may widely exist on the parent body (24) Themis. In this
work, we employ the Advanced Thermophysical Model as well as mid-infrared
measurements from NASA's Wide-Field Infrared Survey Explorer to explore thermal
parameters of 20 Themis family members. Here we show that the average thermal
inertia and geometric albedo are ~$39.5\pm26.0 ~\rm J m^{-2} s^{-1/2} K^{-1}$
and $0.067\pm0.018$, respectively. The family members have a relatively
moderate roughness fraction on their surfaces. We find that the relatively low
albedos of Themis members are consistent with the typical values of B-type and
C-type asteroids. As aforementioned, Themis family bears a very low thermal
inertia, which indicates a fine and mature regolith on their surfaces. The
resemblance of thermal inertia and geometric albedo of Themis members may
reveal their close connection in origin and evolution. In addition, we present
the compared results of thermal parameters for several prominent families.
