M 81

Bode's Galaxy (Messier 81 or M81) is one of the most noticeable galaxies in the sky, which can be seen even with the naked eye. It is located at a distance of about 12 million light-years from Earth in the constellation Coma Berenices. M81 is a typical spiral galaxy with a bright core and an elongated shape.

Characteristics

• Size: Diameter 96,000 light-years (29.44 kiloparsecs).
• Mass: Exceeds the mass of the Milky Way by 2 times.
• Brightness: M = +6.8, bright enough for observation through binoculars.
• Central black hole: Mass 70 million solar masses.

Features

Star Clusters

M81 is estimated to contain about 210±30 star clusters.

Supernovae

The galaxy hosted supernova SN 1993J, which was the second brightest Type II supernova of the 20th century. It was discovered in March 1993 and changed its spectral signature over time, leading to its classification as a Type IIb supernova.

Black Hole

M81 has an active supermassive black hole at its center, with a mass of about 70 million solar masses. It has an accretion disk and a unidirectional relativistic outflow, and is likely surrounded by a second supermassive black hole with a mass of 0.1 that of the primary.

Location

The galaxy is located in a group of galaxies called the M81 Group, which includes galaxies such as M82, NGC 2403, NGC 4236, and others. M81's interactions with neighboring galaxies such as M82 and NGC 3077 cause gravitational disturbances and the formation of gas filaments, which contributes to active star formation in these galaxies.

Discovery History

The galaxy was discovered by Johann Elert Bode on December 31, 1774, and was later included in the Messier catalog in 1779.

Observations

M81 is an ideal object for observing with binoculars and small telescopes. It can be seen with the naked eye under exceptional conditions, but a telescope with an aperture of at least 8 inches (20 cm) is required for detailed study.

Infrared observations

The galaxy is also actively studied in the infrared range using the Spitzer telescope, which recorded dust emission in the spiral arms of the galaxy associated with star formation processes.

Interesting facts

• FRB 20200120E: In 2022, M81 was associated with the source of a repeating fast radio burst (FRB).

• Gravitational interactions: Interaction with neighboring galaxies M82 and NGC 3077 leads to the formation of massive stellar streams.

Significance

The M81 galaxy is an important object for astronomical research, as it provides unique data on the structure of galaxies, star formation, and galaxy interactions. Due to its brightness and proximity to Earth, it is an excellent object for observations by both professional and amateur astronomers.