Interpretation of (596) Scheila's Triple Dust Tails

Masateru Ishiguro (1) , Hidekazu Hanayama (2) , Sunao Hasegawa (3) , Yuki Sarugaku (3) , Jun-Ichi Watanabe (2, 4) , Hideaki Fujiwara (5) , Hiroshi Terada (5) , Henry H. Hsieh (6) , Jeremie Vaubaillon (7) , Nobuyuki Kawai (8) , Kenshi Yanagisawa (9) , Daisuke Kuroda (9) , Takeshi Miyaji (2, 4) , Hideo Fukushima (2, 4) , Kouji Ohta (10) , Hiromi Hamanowa (11) , Junhan Kim (12) , Jeonghyun Pyo (13) , Akiko M. Nakamura (14)

1 Department of Physics and Astronomy [Seoul]
2 Ishigakijima Astronomical Observatory
3 ISAS - Institute of Space and Astronautical Science
4 NAOJ - National Astronomical Observatory of Japan
5 Subaru Telescope
6 Institute for Astronomy [Honolulu]
7 IMCCE - Institut de Mécanique Céleste et de Calcul des Ephémérides
8 Department of Physics [Tokyo]
9 Okayama Astrophysical Observatory
10 Department of Astronomy
11 Hamanowa Astronomical Observatory
12 Yangcheon-gu
13 KASI - Korea Astronomy and Space Science Institute
14 Department of Earth and Planetary Sciences [Kobe]

Strange-looking dust cloud around asteroid (596) Scheila was discovered on 2010 December 11.44-11.47. Unlike normal cometary tails, it consisted of three tails and faded within two months. We constructed a model to reproduce the morphology of the dust cloud based on the laboratory measurement of high velocity impacts and the dust dynamics. As the result, we succeeded in the reproduction of peculiar dust cloud by an impact-driven ejecta plume consisting of an impact cone and downrange plume. Assuming an impact angle of 45 deg, our model suggests that a decameter-sized asteroid collided with (596) Scheila from the direction of (alpha, delta) = (60deg, -40deg) in J2000 coordinates on 2010 December 3. The maximum ejection velocity of the dust particles exceeded 100 m/s. Our results suggest that the surface of (596) Scheila consists of materials with low tensile strength.

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]; Planétologie et astrophysique de la terre [astro-ph.EP]

Masateru Ishiguro, Hidekazu Hanayama, Sunao Hasegawa, Yuki Sarugaku, Jun-Ichi Watanabe, et al.. Interpretation of (596) Scheila's Triple Dust Tails. The Astrophysical journal letters, 2011, 741 (1), pp.L24. ⟨10.1088/2041-8205/741/1/L24⟩. ⟨hal-00659832⟩