by APOD Robot » Sun Jul 13, 2014 4:10 am
Planetary Nebula NGC 2818 from Hubble
Explanation: NGC 2818 is a beautiful
planetary nebula, the gaseous shroud of a
dying sun-like star. It could well offer a glimpse of the future that awaits our own Sun after spending another 5 billion years or so steadily using up hydrogen at its core, and then finally helium, as fuel for
nuclear fusion.
Curiously, NGC 2818 seems to lie within an open star cluster, NGC 2818A, that is some 10,000 light-years distant toward the southern constellation
Pyxis (the Compass). At the distance of the
star cluster, the nebula would be about 4 light-years across. But accurate velocity measurements show that the nebula's own velocity is very different from the cluster's member stars. The result is
strong evidence that
NGC 2818 is only by chance found along the line of sight to the star cluster and so
may not share the cluster's distance
or age. The
Hubble image is a composite of exposures through narrow-band filters, presenting emission from
nitrogen,
hydrogen, and
oxygen atoms in the nebula as red, green, and blue hues.
[/b]
[url=http://apod.nasa.gov/apod/ap140713.html][img]http://apod.nasa.gov/apod/calendar/S_140713.jpg[/img] [size=150]Planetary Nebula NGC 2818 from Hubble[/size][/url]
[b] Explanation: [/b] NGC 2818 is a beautiful [url=http://heritage.stsci.edu/2000/28/pne.html]planetary nebula[/url], the gaseous shroud of a [url=http://hubblesite.org/newscenter/archive/releases/1997/38/background/]dying sun-like star[/url]. It could well offer a glimpse of the future that awaits our own Sun after spending another 5 billion years or so steadily using up hydrogen at its core, and then finally helium, as fuel for [url=http://hyperphysics.phy-astr.gsu.edu/Hbase/astro/astfus.html]nuclear[/url] fusion. [url=http://adsabs.harvard.edu/abs/1984ApJ...287..341D]Curiously[/url], NGC 2818 seems to lie within an open star cluster, NGC 2818A, that is some 10,000 light-years distant toward the southern constellation [url=http://www.hawastsoc.org/deepsky/pyx/index.html]Pyxis[/url] (the Compass). At the distance of the [url=http://asterisk.apod.com/viewtopic.php?f=24&t=18009]star cluster[/url], the nebula would be about 4 light-years across. But accurate velocity measurements show that the nebula's own velocity is very different from the cluster's member stars. The result is [url=http://arxiv.org/abs/0710.2900]strong evidence[/url] that [url=http://adsabs.harvard.edu/abs/2012ApJ...751..116V]NGC 2818[/url] is only by chance found along the line of sight to the star cluster and so [url=http://amazinganimalstories.com/wp-content/uploads/2014/01/o-JERK-CAT-WANTS-ALL-THE-FOOD-facebook.jpg]may not share[/url] the cluster's distance [url=http://apod.nasa.gov/apod/ap990305.html]or age[/url]. The [url=http://heritage.stsci.edu/2009/05/]Hubble image is[/url] a composite of exposures through narrow-band filters, presenting emission from [url=http://periodic.lanl.gov/7.shtml]nitrogen[/url], [url=http://periodic.lanl.gov/1.shtml]hydrogen[/url], and [url=http://en.wikipedia.org/wiki/Oxygen]oxygen[/url] atoms in the nebula as red, green, and blue hues.
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