Rotation and cometary activity of KBO (29981) 1999 TD10

We describe observations of the scattered Kuiper Belt object (29981) 1999 TD10 performed during five observing runs at two observatories, over 370 days from 2000 September to 2001 September. They show significant brightness variations that fit a double-peaked lightcurve with period 15.448±0.012 h in V and R bands. The phase effect in V band, 0.09±0.01 mag deg−1, is smaller than that of Pluto but larger than that of several KBOs, while in R band it is 0.030±0.005 mag deg−1. We find color variation between the two bands, which implies a non-homogeneous albedo distribution on the surface. Evidence of surface activity near perihelion in the form of a coma/tail is presented using radial image profiles and a 2D contour map.