This time-lapse video was put together from Hubble Space Telescope photos. It shows two asteroids with comet-like features orbiting each other. The asteroid pair, called 2006 VW139/288P, was observed in 2016, just before its closest approach to the Sun. The photos reveal the binary system has a tail like a comet. The apparent movement of the tail is caused by changes in the relative alignment between the Sun, Earth, and 2006 VW139/288P between observations. The tail orientation is also affected by a change in the particle size. The pair was emitting relatively large particles (about 1 mm) in late July, and the tail was pointing in more or less the same direction as most of the particle emissions. However, after 20 September, 2016, the tail began to point in the opposite direction as pressure of sunlight pushed smaller (about 10 µm) dust particles away from the Sun.
Credits: NASA, ESA, and J. DePasquale and Z. Levay (STScI)