M 109

Spiral Galaxy M109 (NGC 3992), type SBc,

M108 when they detected and measured

M97, but M109, together with M108, were not

added to the catalog until 1953, by Owen

Gingerich.

this galaxy independently, and cataloged it as H IV.61.

Kenneth Glyn Jones has erroneously misclassified M109 in his General

Description chapter 1 as type Sb, while in the galaxy description, he

correctly gives its class as SBc.

M109 is about 7-by-4 arc minutes in angular extent, and of apparent visual

magnitude 9.5 or 9.6. Visually, only its bright central region together

with the bar can be seen, and appear pear-shaped in smaller telescopes,

“with a strong suspicion of a granular texture” (Mallas).

According to Brent Tully’s Nearby Galaxies Catalog, M109 is about

55 million light years distant, as it is receding at 1142 km/sec, and a

member of the Ursa Major Cloud, a giant but loose agglomeration of galaxies.

Tully took individual distances from the redshift in a model taking the

Virgo-centric flow into account. The distance of this galaxy, however, may

be a bit smaller, as the average recession in this cloud is lower, and some

part of the surplus may be peculiar velocity.

In a newer article, published in

AJ 112, p. 2471 (1996), Brent Tully and his coworkers establish

the existence of this Ursa Major Cluster, as they now call it, by

identifying 79 member galaxies (among them M109).

More images of M109
Amateur images of M109
The type I supernova 1956A occured in this galaxy on March 17, 1956, and

reached 12.8 mag (or up to 12.3, according to some sources) in its maximum.
NED data of M109

Hartmut Frommert

([email protected])

Christine Kronberg

([email protected])

Last Modification: 10 Jul 1999, 10:50 MET