Astronomy Picture of the Day
Posted By admin On December 6, 2011 @ 8:53 pm In Photo Essays | Comments Disabled
For reasons unknown, star V838 Mon’s outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy in January 2002. Then, just as suddenly, it faded. A stellar flash like this had never been seen before. It’s true that supernovae and novae expel matter out into space. But while the V838 Mon flash appears to expel material into space, what is seen here is actually an outwardly moving light echo of the bright flash.
[1]
Light Echoes from V838 Mon
Explanation: For reasons unknown [5], star V838 Mon [6]‘s outer surface suddenly greatly expanded with the result that it became the brightest star in the entire Milky Way Galaxy [7] in January 2002. Then, just as suddenly, it faded. A stellar flash [8] like this had never been seen before. It’s true that supernovae [9] and novae [10] expel matter out into space. But while the V838 Mon [11] flash appears to expel material into space, what is seen here [12] is actually an outwardly moving light echo [13] of the bright flash. In a light echo [14], light from the flash is reflected by successively more distant rings [15] in the ambient interstellar dust [16] that already surrounded the star. V838 Mon [17] lies about 20,000 light years [18] away toward the constellation [19] of Monoceros [20] the unicorn. In this Hubble Space Telescope image from February 2004 [17], the light echo is about six light years [21] in diameter.
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URL to article: http://www.berthoudrecorder.com/2011/12/06/astronomy-picture-of-the-day-95/
URLs in this post:
[1] Image: http://www.berthoudrecorder.com/wp-content/uploads/2011/12/v838mon_hst_big.jpg
[2] NASA: http://www.nasa.gov./
[3] ESA: http://spacetelescope.org/
[4] STScI: http://www.stsci.edu/portal/
[5] reasons unknown: http://adsabs.harvard.edu/abs/2009A%26A...503..899T
[6] V838 Mon: http://apod.nasa.gov/apod/ap030327.html
[7] Milky Way Galaxy: http://apod.nasa.gov/apod/ap050605.html
[8] stellar flash: http://en.wikipedia.org/wiki/V838_Mon
[9] supernovae: http://heasarc.gsfc.nasa.gov/docs/snr.html
[10] novae: http://csep10.phys.utk.edu/astr162/lect/novae/novae.html
[11] V838 Mon: http://hubblesite.org/newscenter/archive/2003/10/text
[12] seen here: http://hubblesite.org/newscenter/archive/releases/2003/10/image/d/
[13] light echo: http://apod.nasa.gov/apod/ap971023.html
[14] light echo: http://adsabs.harvard.edu/abs/2003Natur.422..405B
[15] more distant rings: http://www.youtube.com/watch?v=j2NvAPSwUc0
[16] interstellar dust: http://apod.nasa.gov/apod/ap990509.html
[17] V838 Mon: http://hubblesite.org/newscenter/archive/releases/2004/10/fastfacts/
[18] light years: http://chandra.harvard.edu/photo/cosmic_distance.html
[19] constellation: http://apod.nasa.gov/apod/ap030401.html
[20] Monoceros: http://en.wikipedia.org/wiki/Monoceros
[21] light years: http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html
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