Astronomy Picture of the Day
Astronomy Picture of the Day
Discover the cosmos! [1] Each day a different image or photograph of our
fascinating universe is featured, along with a brief explanation written by a
professional astronomer.
2019 February 13
[2]
The Helix Nebula in Hydrogen and Oxygen
Image Credit & Copyright: Andrew Campbell [3]
Explanation: Is the Helix Nebula looking at you? No, not in any biological
sense, but it does look quite like an eye. The Helix Nebula [4] is so named
because it also appears that you are looking down the axis of a helix [5] . In
actuality, it is now understood to have a surprisingly complex geometry [6] ,
including radial filaments and extended outer loops [7] . The Helix Nebula (
aka [8] NGC 7293) is one of brightest and closest examples of a planetary
nebula [9] , a gas cloud created [10] at the end of the life of a Sun-like
star. The remnant central stellar core, destined to become a white dwarf star
[11] , glows in light so energetic [12] it causes the previously expelled gas
to fluoresce [13] . The featured picture [14] , taken in the light emitted by
oxygen [15] (shown in blue) and hydrogen [16] (shown in red), was created
from 74 hours of exposure over three months from a small telescope in a
backyard of suburban Melbourne [17] , Australia [18] . A close-up [19] of the
inner edge [20] of the Helix Nebula shows complex gas knots of unknown origin
[21] .
Tomorrow's picture: open space
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Authors & editors: Robert Nemiroff [33] (MTU [34] ) & Jerry Bonnell [35]
(UMCP [36] )
NASA Official: Phillip Newman Specific rights apply [37] .
NASA Web Privacy Policy and Important Notices [38]
A service of: ASD [39] at NASA [40] / GSFC [41]
& Michigan Tech. U. [42]
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Site notes:
[1] archivepix.html
[2] image/1902/Helix_Campbell_1585.jpg
[3] https://www.facebook.com/AndysAstropix/
[4] https://en.wikipedia.org/wiki/Helix_Nebula
[5] http://mathworld.wolfram.com/Helix.html
[6] http://hubblesite.org/image/1605/news_release...
[7] ap180103.html
[8] https://grammarist.com/acronym/a-k-a-or-aka/
[9] https://en.wikipedia.org/wiki/Planetary_nebul...
[10] http://www.youtube.com/watch?v=KXNSYo8ZdoU
[11] https://imagine.gsfc.nasa.gov/science/objects...
[12] https://science.nasa.gov/ems/10_ultravioletwa...
[13] https://www.youtube.com/watch?v=YvN8zFhWn04
[14] https://www.astrobin.com/378608/C/
[15] https://periodic.lanl.gov/8.shtml
[16] http://www.astronomyknowhow.com/hydrogen-alph...
[17] https://www.youtube.com/watch?v=fxRa7czldw0
[18] https://en.wikipedia.org/wiki/Australia
[19] http://www.youtube.com/watch?v=UwAKNMC2PeM
[20] ap080413.html
[21] http://adsabs.harvard.edu/abs/2002ApJ...573L....
[22] ap190212.html
[23] archivepix.html
[24] lib/apsubmit2015.html
[25] lib/aptree.html
[26] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apo...
[27] calendar/allyears.html
[28] /apod.rss
[29] lib/edlinks.html
[30] lib/about_apod.html
[31] http://asterisk.apod.com/discuss_apod.php?dat...
[32] ap190214.html
[33] http://www.phy.mtu.edu/faculty/Nemiroff.html
[34] http://www.phy.mtu.edu/
[35] https://antwrp.gsfc.nasa.gov/htmltest/jbonnel...
[36] http://www.astro.umd.edu/
[37] lib/about_apod.html#srapply
[38] https://www.nasa.gov/about/highlights/HP_Priv...
[39] https://astrophysics.gsfc.nasa.gov/
[40] https://www.nasa.gov/
[41] https://www.nasa.gov/centers/goddard/
[42] http://www.mtu.edu/
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