M61

M61 or M-61 may refer to:

In transportation:

In science:

In firearms and military equipment:

M26 grenade

The M26 is a fragmentation hand grenade made by the United States.

Description

The M26 is a fragmentation grenade developed by the United States military. It entered service around 1952 and was used in combat during the Korean War. Its distinct lemon shape led it to being nicknamed the "lemon grenade" (compare Russian F1 grenade, and Mk 2 Pineapple grenade, with similar nicknames).

Fragmentation is enhanced by a special pre-notched fragmentation coil that lies along the inside of the grenade's body. This coil had a circular cross-section in the M26 grenade and an improved square cross-section in the M26A1 and later designs.

The grenades were stored inside two-part cylindrical fiberboard shipping tubes (Container M289) and were packed 25 or 30 to a crate.

History

The M26 was developed as a result of studies on the Mk 2. Unlike its previous counterpart, its M204A1 fuse creates no tell-tale smoke or sparks when ignited and its powder train is almost silent while it burns down. Its Composition B filler was considered safer than the flaked or granular TNT filling used in the Mk 2.

Messier 61

Messier 61 (also known as M61 or NGC 4303) is a barred spiral galaxy in the Virgo Cluster. It was discovered by Barnabus Oriani on May 5, 1779.

Properties

M61 is one of the largest members of Virgo, belonging to the subunit known as S Cloud

It has an Active galactic nucleus and it is classified as a starburst galaxy, with a candidate supermassive black hole with a mass around 5 million times that of our Sun on its center. This object is associated with a young, massive star cluster with a mass 100,000 times the one of the Sun, a radius of 3.1 parsecs and an age of 4 million years. Surrounding it, there's a nuclear spiral with a radius of 225 parsecs formed by several massive star-forming regions, that may be associated with a second bar much smaller than the main one of this galaxy.

Star formation is also high across M61's disk, perhaps due to interactions with her satellite galaxies NGC 4292 and NGC 4303B.

Unlike most late-type galaxies of the Virgo Cluster, M61 does not show a deficiency of neutral hydrogen