M96 is an intermediate spiral galaxy 35 million light-years distant in the constellation of Leo. At magnitude +9.6, it's the brightest member of the Leo I or M96 group of galaxies that also contains M95, M105 and at least another 21 fainter galaxies. The grouping is one of many that lie within the Virgo Supercluster. The three galaxies are amongst the fainter objects in Messiers catalogue but all are visible with large 15x70 or 20x80 binoculars from a dark site, appearing as faint smudges of light.
M96 is an unusual galaxy in the sense that it has asymmetric arms and a displaced core that were probably caused by gravitational pulling from other nearby galaxies. It was discovered, along with M95, by Pierre Méchain on March 20, 1781. Charles Messier including both items in his catalogue four days later. M105 was not included in the original Messier catalogue but added much later by Helen Sawyer Hogg in 1947.
The galaxies are located in the southern middle section of the relatively large and bright constellation of Leo the Lion, which lies east of Cancer and to the west of Virgo. Leo contains one first magnitude star, Regulus (α Leo - mag. +1.4), which happens to be the brightest star in the surrounding region of sky. About 24 degrees east and two degrees north of Regulus is the third brightest star in Leo, Denebola (β Leo - mag. +2.1). Imagine a line connecting Regulus with Denebola with M95, M96 and M105 located just less than half way along this line. The northernmost member of the trio is M105 with M96 located 50 arc minutes south of M105 and M95 positioned 40 arc minutes west of M96.
They are best seen during the months of March, April and May.
It's difficult to notice much detail in M96 through a small 80mm (3.1-inch) telescope but it's possible, on nights of good seeing, to make out the oval shaped core. Larger apertures of 200mm (8-inch) or greater bring out more, including the bright core surrounded by wispy nebulosity that hints at the true spiral nature of the galaxy. In total, M96 spans 7.8 x 5.2 arcminutes of apparent sky.
In the same field of view as M96 is M95 which displays an oval patch of diffuse light with a bright core. The third galaxy M105 is the least impressive of the three, appearing only as a small faint ball of fuzz. Since each galaxy is of a different type - barred spiral galaxy M95, intermediate spiral galaxy M96 and elliptical galaxy M105 - it's interesting to compare how they appear through the eyepiece.
M96 is 80,000 light-years in diameter while M95 and M105 measure 46,000 and 55,000 light-years in diameter respectively. On May 9, 1998 a type Ia supernova (SN 1998bu) was discovered in M96, peaking at magnitude +11.8.
M96 Data Table
|Object Type||Intermediate Spiral galaxy|
|RA (J2000)||10h 46m 46s|
|DEC (J2000)||11d 49m 25s|
|Apparent Size (arc mins)||7.8 x 5.2|
|Number of Stars||100 Billion|
|Notable Feature||M96 is a member of the Leo I or M96 group of galaxies|