M87 is a supergiant elliptical galaxy that's a prominent member of the Virgo cluster of galaxies. It's one of the largest and most luminous galaxies known and a strong source of radiation, particularly radio and X-ray emissions. At the centre of M87 is a supermassive black hole with a jet of extremely energetic plasma extending outwards for at least 5000 light-years. The galaxy is therefore an interesting object for both professional and amateur astronomers alike.
With an apparent magnitude of +8.6, M87 is the second brightest of the Virgo cluster galaxies; only M49 at mag. +8.4 is brighter. On dark moonless nights it's visible with 7x50 or 10x50 binoculars, appearing as a faint hazy patch of light. The galaxy was one of eight discovered by Charles Messier on March 18, 1781. On this day he also re-discovered fine globular cluster M92.
M87 lies at the heart of the Virgo cluster. It can be found by imagining a line connecting Denebola (β Leo - mag. +2.1) with Vindemiatrix (ε Vir - mag. +2.8). Just over half way along this line is M87. Faint elliptical galaxy M89 is positioned just over a degree east of M87 with galaxy pair M84/M86 located 1.5 degrees northwest of M87.
The Virgo galaxies are best seen during the months of March, April and May.
Through a 80mm (3.1-inch) scope M87 appears as a fuzzy elliptical ball of light that's brighter towards the centre. Even with larger scopes the galaxy remains essentially featureless although much easier to detect. It has no distinctive dust lanes and diminishes in luminosity with distance from the center. The jet is far too faint to be observed with most backyard scopes, although it has been reportedly observed with extremely large amateur scopes under excellent conditions. It is much easier to image or photograph. Within the same low-power field as M87 are two fainter elliptical galaxies, NGC 4476 and NGC 4378.
M87 spans 8.3 x 6.6 arc minutes of apparent sky. It's located 53.5 million light-years distant, which corresponds to a spatial diameter of 130,000 light-years and is estimated to contain a trillion stars. The only supernova recorded for in M87 occurred in February 1919, but was not detected until 1922 when photographic plates were examined. The maximum brightness was estimated at +11.5.
Orbiting M87 are an extremely large number of globular clusters of which at least 12,000 have been identified. For comparison our Milky Way galaxy contains only 200.
The galaxy is also referred to as Virgo A.
M87 Data Table
|Object Type||Elliptical galaxy|
|RA (J2000)||12h 30m 49.3s|
|DEC (J2000)||12d 23m 26s|
|Apparent Size (arc mins)||8.3 x 6.6|
|Number of Stars||1 Trillion|
|Notable Feature||Contains a spectacular jet of ejected matter|