At http://phys.org/print304851254.html … the December Geminids are a regular meteor shower emerging out of that part of the sky defined as the constellation of Gemini, and they always appear, year on year. However, their progenitor comet is unknown. There is no comet that matches their orbit – but there is an asteroid. This is Phaethon. It was discovered in 1983 by NASAs IRAS satellite. The problem is that Phaethon is a typical rocky body assigned to a non cometary status, yet swoops by the Sun every 1.4 years – much like a comet.
No evidence of a tail on Phaethon has been seen – until the NASA STEREO probe took a close look as it passed by the Sun. In 2010 the probe saw a brightening of the asteroid as it approached the Sun. IN 2012 s small tail was seen behind the rock. Not enought to account for the Geminids. That suggests Phaethon experienced a 'big event' in the recent past (according to David Jewitt of UCLA)