For 12 years the Solar and Heliospheric Observatory — SOHO for short — has stared at the Sun at visible, ultraviolet, and X-ray wavelengths. This is not a particularly safe practice for human eyes, of course, but the spacecraft's sensors can handle all those high-energy photons just fine. A joint project of the European Space Agency and NASA, SOHO has been there to sound the alarm whenever our star erupts and spews huge blobs of magnetized, superheated plasma in Earth's general direction.
But all this time SOHO has been moonlighting as a comet catcher, netting astronomers some 1,350 discoveries. To date, they've all been kamikaze comets — "sungrazers" that race in close and vaporize themselves in a matter of days.
SOHO's latest find is different: it's a repeat visitor first seen in September 1999, and then again in September 2003. Two years ago a German graduate student named Sebastian Hönig realized that the two objects had nearly identical four-year orbits and thus were probably one and the same. He predicted that it would make an encore appearance on September 11th, and it did.
Although Hönig did the spade work, he doesn't get the naming rights. Neither do Terry Lovejoy, the Australian who first spotted the comet in SOHO imagery in 1999; Kazimieras Cernis (Lithuania, 2003); or Bo Zhou (China, 2007). Instead, this new periodic visitor will henceforth be known as Comet SOHO (P/2007 R5). Hey, don't blame me — take it up with the IAU.