Mystery Object Behaves Both Like a Comet and an Asteroid

Something awfully curious is happening 250 million miles away in the asteroid belt.
Nothing quite like it has ever been seen before.
There’s a newly discovered object that superficially looks like a comet but lives among the asteroids.
The distinction? Comets swoop along elliptical orbits close in to the sun and grow long gaseous and dusty tails as ices sublimate off their solid nucleus and release dust. But asteroids are mostly in more circular orbits and are not normally expected to be as volatile as comets.
The puzzling object was discovered on January 6 by the Lincoln Near-Earth Asteroid Research (LINEAR) sky survey.

Full article by Ray Villard on Discovery News