in the constellation Ursa Major
100 million times the mass of the Sun
Diameter roughly the size of the orbit of Mars
NGC 4335 is a giant elliptical galaxy that appears near the intersection between the bowl and handle of the Big Dipper.
Like all elliptical galaxies, to the eye alone it is pretty boring. It looks like a fat, fuzzy rugby ball, with none of the beautiful and graceful structure of a spiral galaxy. The galaxy consists of mainly old, faint stars that zip around the galaxy's center in random orbits.
Detailed observations of the galaxy's core, however, reveal more structure, including a disk of dust that spans about 2,500 light-years, with a smaller disk of gas possibly embedded inside it.
Observations of the gas disk with an instrument aboard Hubble Space Telescope reveal that the gas near the center of the disk is orbiting much faster than gas near the edge of the disk. The different in orbital velocity suggests that the gas is orbiting a supermassive black hole at least 100 million times as massive as the Sun. (Various models of the black hole say it could be up to three billion times the Sun's mass, although those estimates are less solidly based than the smaller size.)
Hubble could not see the stars embedded within the disk, but the 4.2-meter (168-inch) William Herschel Telescope in the Canary Islands could. The stellar orbits confirm the presence of a large, heavy mass in the galaxy's core.
Did you find what you were looking for on this site? Take our site survey and let us know what you think.
This document was last modified: July 16, 2012.