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The Subaru Seminar is usually held in Room 104 of the Hilo Base Facility, adjacent to the main lobby. Everyone is welcome to attend. If you are interested in giving a seminar, please contact Subaru seminar organizers (Tae-Soo Pyo, Sherry Yeh, Nagayoshi Ohashi) by email : (please change"_at" to @).

September 4, Thursday, at 11:00 am

" Time-series Photometry of Earth Flyby Asteroid 2012 DA14 "

Tsuyoshi Terai

(Subaru Telescope)

2012 DA14 is a near-Earth object in diameter of several ten meters, which passed closely to the Earth at a distance of about 27,700 km inside a geosynchronous orbit on February 15, 2013 UT. Around the closest approach, the asteroid lightened brighter than 7th magnitude in the optical and had a wide variation of solar phase angle. This event was a great opportunity to investigate the surface properties of small-sized asteroids, such as geometric albedo and regolith structure. We performed a time-series photometric observation for 2 hours around the closest approach of 2012 DA14 using the 0.55-m telescope at Saitama University. Although this observation was very difficult due to the extremely fast sky motion (50 arcmin/min in maximum!), we successfully acquired good photometric data all over the observation. We also performed an additional observation on the next night and determined the rotation period and lightcurve amplitude. Our data analysis shows that the phase curve is significantly shallower than that of L-type asteroids which 2012 DA14 has been classified as. 2012 DA14 is likely to be coated with a coarse surface that lacks fine regolith particles and/or a high albedo surface.

Seminars are also held at JAC, CFHT, and IfA.

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