Fast Rotation of a Sub-km-sized Near-Earth Object 2011 XA3
  We present lightcurve observations and their multiband photometry for near-Earth object (NEO) 2011 XA3. The lightcurve has shown a periodicity of 0.0304 +- 0.0003 day (= 43.8 +- 0.4 min). The fast rotation shows that 2011 XA3 is in a state of tension (i.e. a monolithic asteroid) and cannot be held together by self-gravitation. Moreover, the multiband photometric analysis indicates that the taxonomic class of 2011 XA3 is S-complex, or V-type. Its estimated effective diameter is 225 +- 97 m (S-complex) and 166 +- 63 m (V-type), respectively. Therefore, 2011 XA3 is a candidate for the second-largest fast-rotating monolithic asteroid. Moreover, the orbital parameters of 2011 XA3 are apparently similar to those of NEO (3200) Phaethon but F/B-type. We computed the orbital evolutions of 2011 XA3 and Phaethon. However, the results of the computation and distinct taxonomy indicate that neither of the asteroids is of common origin. 
S. Urakawa, K. Ohtsuka, S. Abe, T. Ito, T. Nakamura
astro-ph.EP