Detection of Remnant Dust Cloud Associated with the 2007 Outburst of 17P/Holmes

January 2016 • 2016ApJ...817...77I

Authors • Ishiguro, Masateru • Sarugaku, Yuki • Kuroda, Daisuke • Hanayama, Hidekazu • Kim, Yoonyoung • Kwon, Yuna G. • Maehara, Hiroyuki • Takahashi, Jun • Terai, Tsuyoshi • Usui, Fumihiko • Vaubaillon, Jeremie J. • Morokuma, Tomoki • Kobayashi, Naoto • Watanabe, Jun-ichi

Abstract • This article reports a new optical observation of 17P/Holmes one orbital period after the historical outburst event in 2007. We detected not only a common dust tail near the nucleus but also a long narrow structure that extended along the position angle 274.°6 ± 0.°1 beyond the field of view (FOV) of the Kiso Wide Field Camera, I.e., >0.°2 eastward and >2.°0 westward from the nuclear position. The width of the structure decreased westward with increasing distance from the nucleus. We obtained the total cross section of the long extended structure in the FOV, C_FOV = (2.3 ± 0.5) × 10¹⁰ m². From the position angle, morphology, and mass, we concluded that the long narrow structure consists of materials ejected during the 2007 outburst. On the basis of the dynamical behavior of dust grains in the solar radiation field, we estimated that the long narrow structure would be composed of 1 mm-1 cm grains having an ejection velocity of >50 m s^-1. The velocity was more than one order of magnitude faster than that of millimeter-centimeter grains from typical comets around a heliocentric distance r_h of 2.5 AU. We considered that sudden sublimation of a large amount of water-ice (≈10³⁰ mol s^-1) would be responsible for the high ejection velocity. We finally estimated a total mass of M_TOT = (4-8) × 10¹¹ kg and a total kinetic energy of E_TOT = (1-6) × 10¹⁵ J for the 2007 outburst ejecta, which are consistent with those of previous studies that were conducted soon after the outburst.

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Yuna Kwon

Postdoctoral Research Associate