Image Credit: Caltech / Robert Quimby / Nature
Last week, a group of astronomers led by Caltech astronomer Robert Quimby announced that they had learned a few crucial pieces of information about these enigmatic sources. This new evidence suggests that we are seeing a new type of stellar explosion, though we still don't know exactly what we are seeing.
Two years ago, I attended a conference on supernovae (exploding stars), and I blogged about weird objects that we could not explain. In apparently blank parts of the sky, a couple of "new stars" had appeared and slowly faded away, just like supernovae. Only these new objects changed their brightness on much longer time scales than normal supernovae, they did not appear to be located inside another galaxy, and their spectra showed weird features that could not be identified with certitude. Many different explanations were proposed, from white dwarf stars in our own Milky Way Galaxy to carbon stars being shredded by black holes halfway across the Universe.
These new types of supernovae were discovered as part of the Palomar Transient Factory program. This program continuously searches several patches of the night sky, looking at these same patches over and over ...