The NASA Science News website has a story on a discovery reported in
the Nov 7th issue of the Astrophysical Journal Letters.
Astronomers using the Hubble telescope have observed that asteroid P/2013 P5 has
been ejecting dust periodically for at least five months. More recently it was
observed with six comet-like tails making the asteroid appear like a "rotating
lawn sprinkler".
Story and photos here -
http://science.nasa.gov/science-news.../07nov_6tails/