For the first time, astronomers catch asteroid in the act of changing color

Last December, scientists discovered an “active” asteroid within the asteroid belt, sandwiched between the orbits of Mars and Jupiter. The space rock, designated by astronomers as 6478 Gault, appeared to be leaving two trails of dust in its wake—active behavior that is associated with comets but rarely seen in asteroids.

Source:
https://phys.org/news/2019-08-astronomers-asteroid.html