Horsehead Nebula

Dark nebula


name = Horsehead Nebula
type = dark nebula/diffuse nebulae
epoch = J2000.0
ra = 05^h 40^m 59.0^s
dec = −02° 27′ 30.0"
dist_ly = 1,500 ly
appmag_v = –
size_v = 8 × 6 arcmins
constellation = Orion
radius_ly = –
absmag_v = –
notes = –
names = IC 434, Barnard 33,
LDN 1630, M3T 31,
[OS98] 52

The Horsehead Nebula (also known as Barnard 33 in bright nebula IC 434) is a dark nebula in the Orion constellation. The nebula is located just below Alnitak, the star furthest left on Orion's Belt, and is part of the much larger Orion Molecular Cloud Complex. It is approximately 1500 light years from Earth. It is one of the most identifiable nebulae because of the shape of its swirling cloud of dark dust and gases, which is similar to that of a horse's head. The shape was first noticed in 1888 by Williamina Fleming on photographic plate B2312 taken at the Harvard College Observatory.

The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field. Bright spots in the Horsehead Nebula's base are young stars just in the process of forming.

ee also

* Horsehead Nebula in fiction

External links

* [http://www.glyphweb.com/esky/nebulae/ic434.html The Horsehead Nebula @ The Electronic Sky]
* [http://hubblesite.org/newscenter/newsdesk/archive/releases/2001/12/image/a Hubble Observes the Horsehead Nebula]
* [http://adsabs.harvard.edu/cgi-bin/bib_query?1990PASP..102.1337W The discovery of early photographs of the Horsehead nebula, by Waldee and Hazen]
* [http://home.earthlink.net/~astro-app/horsehead/B33-19thC_4.htm The Horsehead Nebula in the 19th Century, by Waldee]
* [http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1890AnHar..18..113P&db_key=AST&data_type=HTML&format=&high=44215828ae04166 Detection of new nebulae by photography, by Pickering]
* [http://www.journals.uchicago.edu/AJ/journal/issues/v125n4/202465/202465.html Looking into the Horsehead Nebula, by Pound, Reipurth, and Bally]
* [http://www.spacetelescope.org/bin/images.pl?searchtype=freesearch&string=Horsehead+Nebula Horsehead Nebula at ESA/Hubble]
* [http://ryutao.main.jp/english/stl_batou_l.html The Horsehead Nebula at the Astro-Photography site of Mr. T. Yoshida.]
* [http://wikisky.org/?img_source=IMG_all&zoom=8&img_borders=1&ra=5.68&de=-2.5 The Horsehead Nebula on interactive astro-photography survey at Wikisky.org]
* [http://www.stargazer-observatory.com/horse-n-flame.html The Horsehead-Nebula imaged with a semiprofessional amateur-telescope]