Multiband Optical Observation of The P/2010 A2 Dust Tail

Kim Junhan

Ishiguro Masateru

Hanayama Hidekazu

Hasegawa Sunao

Usui Fumihiko

Yanagisawa Kenshi

Sarugaku Yuki

Watanabe Jun-ichi

Yoshida Michitoshi

Astrophysical Journal Letters

An inner main-belt asteroid, P/2010 A2, was discovered on 2010 January 6. Based on its orbital elements, it is considered that the asteroid belongs to the Flora collisional family, where S-type asteroids are common, while showing a comet-like dust tail. Although analysis of images taken by the Hubble Space Telescope and Rosetta spacecraft suggested that the dust tail resulted from a recent head-on collision between asteroids, an alternative idea of ice sublimation was suggested based on the morphological fitting of ground-based images. Here, we report a multiband observation of P/2010 A2 made on 2010 January with a 105 cm telescope at the Ishigakijima Astronomical Observatory. Three broadband filters, g', R-c, and I-c, were employed for the observation. The unique multiband data reveal that the reflectance spectrum of the P/2010 A2 dust tail resembles that of an Sq-type asteroid or that of ordinary chondrites rather than that of an S-type asteroid. Due to the large error of the measurement, the reflectance spectrum also resembles the spectra of C-type asteroids, even though C-type asteroids are uncommon in the Flora family. The reflectances relative to the g' band (470 nm) are 1.096 +/- 0.046 at the R-c band (650 nm) and 1.131 +/- 0.061 at the I-c band (800 nm). We hypothesize that the parent body of P/2010 A2 was originally S-type but was then shattered upon collision into scattering fresh chondritic particles from the interior, thus forming the dust tail.

comets: general

comets: individual (P/2010 A2)

minor planets, asteroids: general

天文学・宇宙科学 [ 440 ]

英語

IOP Publishing Ltd

(c) 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

[ISSN] 2041-8205

[DOI] 10.1088/2041-8205/746/1/L11

[NCID] AA00553264

[DOI] http://dx.doi.org/10.1088/2041-8205/746/1/L11