Thermophysical Modeling of 20 Themis Family Asteroids with WISE/NEOWISE Observations

• Published in: The Astronomical journal Vol. 162; no. 2; pp. 40 - 56
• Main Authors: Jiang, Haoxuan, Ji, Jianghui
• Format: Journal Article
• Language: English
• Published: Madison The American Astronomical Society 01.08.2021; IOP Publishing
• Subjects: ALBEDO; Asteroid belt; ASTEROIDS; Astronomy; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPUTERIZED SIMULATION; GEOMETRY; INFRARED SURVEYS; Main belt asteroids; Mathematical models; MOMENT OF INERTIA; Near-Earth Objects; Parameters; Regolith; Specific heat; SURFACES; Thermal inertia; Thermodynamic properties; Thermophysical models; Water ice
• ISSN: 0004-6256; 1538-3881; 1538-3881
• DOI: 10.3847/1538-3881/ac01c8

Abstract 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 midinfrared 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 ± 26.0 J m −2 s −1/2 K −1 and 0.067 ± 0.018, 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 mentioned, the 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.