The black hole behemoth is 17 billion times the mass of the sun. Astronomers have no clue why it's so big.
Astronomers have found a super-super-massive black hole comprising a whopping and unprecedented 59 percent of the mass of stars in the central bulge of its host galaxy, a discovery that adds a new twist to the mysterious relationship between a galaxy and its black hole.
The black hole inside the small, compact galaxy known as NGC 1277, located about 250 million light years away in the constellation Perseus, weighs in at 17 billion times the mass of the sun.
In comparison, the supermassive black hole at the heart of our Milky Way galaxy is equal to the mass of about 4 million suns.
Typically, black holes account for 0.1 percent of a galaxy's stellar bulge. Until now, the galaxy with the proportionally largest black hole was NCG 4486B, which has a black hole accounting for 11 percent of the combined mass of the central stars.
How 1277's black hole came to be so large is mystery.
"We didn't expect these systems to exist at all, but because the stars move so incredibly fast in the centers of these objects, we know these big black holes exist in these small galaxies," astronomer Remco van den Bosch, with the Max Planck Institute for Astronomy in Germany, wrote in an email to Discovery News.