Messier 81

This stately spiral galaxy holds a black hole at its heart that is 70 million times the mass of the Sun.

Distance

11.6 million light-years

Apparent Magnitude

6.9

constellation

Ursa Major

object type

Spiral Galaxy

M81
This stunning Hubble image was assembled using observations in visible and infrared light. The galaxy’s spiral arms, which wind all the way down into its nucleus, are made up of young, bluish, hot stars formed in the past few million years.
NASA, ESA and the Hubble Heritage Team (STScI/AURA)

Discovered by the German astronomer Johann Elert Bode in 1774, M81 is one of the brightest galaxies in the night sky. It is located 11.6 million light-years from Earth in the constellation Ursa Major and has an apparent magnitude of 6.9. Through a pair of binoculars, the galaxy appears as a faint patch of light in the same field of view as M82. A small telescope will resolve M81’s core. The galaxy is best observed during April.

This stunning Hubble image was assembled using observations in visible and infrared light. The galaxy’s spiral arms, which wind all the way down into its nucleus, are made up of young, bluish, hot stars formed in the past few million years. They also host a population of stars formed in an episode of star formation that started about 600 million years ago. Ultraviolet light from hot, young stars is fluorescing the surrounding clouds of hydrogen gas. A number of sinuous dust lanes also wind all the way into the nucleus of M81.

The galaxy’s central bulge contains much older, redder stars. It is significantly larger than the Milky Way’s bulge. A black hole of 70 million solar masses resides at the center of M81 and is about 15 times the mass of the Milky Way’s central black hole. Previous Hubble research showed that the size of the black hole in a galaxy’s nucleus is proportional to the mass of the galaxy’s bulge.

For more information about Hubble’s observations of M81, see:

locator star chart for M81
This star chart for M81 represents the view from mid-northern latitudes for the given month and time.
Image courtesy of Stellarium

Explore Hubble's Messier Catalog

The following pages contain some of Hubble’s best images of Messier objects.

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