Alternate Names

Mayall II

Type

Intermediate mass

Location

near the Andromeda galaxy (M31)

Finder Chart

Distance

2.3 million light-years (0.76 megaparsecs)

Mass

14,000 to 23,000 times the mass of the Sun

Size

52,000-86,000 miles (84,000-138,000 km), roughly equivalent to the diameter of Jupiter

Discovery Methods

• Measuring the motions of stars

G1

An artist's concept of a black hole at the heart of a globular star cluster.

This illustration shows the position of G1 relative to the Andromeda galaxy. M32 and NGC 205 are satellite galaxies of Andromeda, and both appear to contain supermassive black holes at their cores.

A Hubble Space Telescope view of the star cluster G1, which orbits the center of the Andromeda galaxy. The bright stars above the cluster are foreground stars inside the Milky Way galaxy.

Animation takes you into the heart of G1 to view its central black hole.

This document was last modified: November 8, 2011.