Astronomy Picture of the Day
Posted By admin On March 10, 2011 @ 7:55 pm In Photo Essays | Comments Disabled
[1]
NGC 1999: South of Orion
Image Credit & Copyright [2]: Adam Block [3], Mt. Lemmon SkyCenter [4], U. Arizona [5]
Explanation: South of the large star-forming region known as the Orion Nebula, lies bright blue reflection nebula NGC 1999 [6]. Also at the edge of the Orion molecular cloud [7] complex some 1,500 light-years distant, NGC 1999′s illumination is provided by the embedded variable star V380 Orionis. The nebula is marked with a dark sideways T-shape near center in this broad cosmic vista [8] that spans over 10 light-years. The dark shape was once assumed to be an obscuring dust cloud seen in silhouette against the bright reflection nebula. But recent infrared images [9] indicate the shape is likely a hole blown through the nebula itself by energetic young stars. In fact, this region abounds [10] with energetic young stars producing jets and outflows that create luminous shock waves. Cataloged as Herbig-Haro (HH) objects, named for astronomers George Herbig and Guillermo Haro, the shocks appear bright red in this view [11] that includes HH1 and HH2 just below NGC 1999. The stellar jets [12] and outflows push through the surrounding material at speeds of hundreds of kilometers per second.
Visit the NASA/JPL website to view more Astronomy Pictures of the Day [13]
Article printed from Recorder Online: http://www.berthoudrecorder.com
URL to article: http://www.berthoudrecorder.com/2011/03/10/astronomy-picture-of-the-day-30/
URLs in this post:
[1] Image: http://www.berthoudrecorder.com/wp-content/uploads/2011/03/n1999_block1.jpg
[2] Copyright: http://apod.nasa.gov/apod/lib/about_apod.html#srapply
[3] Adam Block: http://www.caelumobservatory.com/index.html
[4] Mt. Lemmon SkyCenter: http://skycenter.arizona.edu/
[5] U. Arizona: http://www.as.arizona.edu/
[6] NGC 1999: http://apod.nasa.gov/apod/ap000302.html
[7] Orion molecular cloud: http://www.seds.org/messier/more/oricloud.html
[8] broad cosmic vista: http://www.caelumobservatory.com/gallery/n1999.shtml
[9] But recent infrared images: http://www.esa.int/esaCP/SEMFEAKPO8G_index_0.html
[10] this region abounds: http://www.noao.edu/outreach/latest/ngc1999about.html
[11] this view: http://skycenter.arizona.edu/news/109
[12] stellar jets: http://hubblesite.org/newscenter/newsdesk/archive/releases/1995/24/astrofile/
[13] Astronomy Pictures of the Day: http://antwrp.gsfc.nasa.gov/apod/
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