Sombrero Galaxy
|
|
The Sombrero Galaxy, also known as Messier Object 104 (M104), Spiral Galaxy M104, or NGC 4594, is a spiral galaxy in the Virgo constellation, about 28 million light years away.
It has a large, bright core, an unusually large central bulge, and a prominent dust lane, or band of dust in the galactic disc. From Earth, it is seen edge-on, which gives it the appearance of a sombrero about one-fifth of the diameter of the full moon.
It is an 8th magnitude spiral galaxy of type Sa or Sb, just faint enough to be invisible to the naked eye but easily visible with small telescopes.
General information
The galaxy lies in the constellation Virgo, though it is not considered a member of the Virgo cluster.
The diameter of M104 is inconsistently cited as being from 50,000 to 140,000 light years. According to the Space Telescope Science Institute's HubbleSite (http://www.hubblesite.org/), M104's diameter is 50,000 light years and it has a mass of about 800 billion Suns.
M104 also has a well-populated system of globular clusters, with at least several hundred visible with large telescopes, and an estimated population of 2,000 or more, many more than orbit the Milky Way.
Recent photos reveal that the galaxy has a very extended galactic halo.
Discovery
It was discovered in the late 1700s, most likely by Pierre Méchain, who mentioned it as a discovery in a May 6, 1783 letter. It was the first Messier object added after the initial publication of the Messier catalog; Messier added it by hand to his personal copy on May 11, 1781, describing it as a "very faint nebula".
It was independently discovered by William Herschel on May 9, 1784.
In 1912, Vesto Slipher discovered that M104 has a large redshift. From this it was calculated that M104 is moving away from Earth at about 1,000 kilometers per second - a speed too high for any object residing in the Milky Way. This was one of the first solid clues that M104 was not a nebula, as was thought at the time, and that the universe is expanding in all directions.
External links
- Messier 104, SEDS Messier pages (http://www.seds.org/messier/m/m104.html)
- HubbleSite: Hubble mosaic of the majestic Sombrero Galaxy (http://hubblesite.org/newscenter/newsdesk/archive/releases/2003/28/image/a)de:Sombreronebel
fr:Galaxie du Sombrero it:M104 nl:Sombreronevel pt:Sombrero sk:Sombrérová galaxia