Image Credit & Copyright: European Southern Observatory (ESO) Very Large Telescope (VLT).
This beautiful catch is from the ESO’s Very Large Telescope (VLT) in the Atacama Desert of Chile and it shows a beautiful chance alignment in the southern constellation of Hydra. The beautifully spherical planetary nebula Abell 33 sits at a distant 2500 light years from Earth. Just overlapping ever so slightly is the star HD 83535 which is actually about 869 light years or about 240 parsecs away in the foreground and not making contact with the planetary at all.
The progenitor star that created this nebula can be seen near the center of the object as a white dwarf. Though, for all intents and purposes dead; this star still shines much brighter than our Sun. Its ultraviolet radiation from the now exposed inner layers ionizing the material for us to view.
As this object made its rounds through the media it has become known to some as the Diamond Ring nebula for obvious reasons. As both the foreground star and planetary are beyond naked eye visibility you will want to observe this with a medium to large telescope (the star is within binocular range) at low magnification and if you can, use an OIII or UHC filter to really bring the nebula out.
Chance alignments like this are fairly common as some star clusters are overlaid with planetary nebula as well as many of the double star systems that we see are actually line of sight doubles and not binary at all. Either way; when the stars, and in this case, stars and planetary nebulae align, the result is beautiful.
If you want more detail on what a planetary nebula is in a little more detail, check out this short post that I threw together: http://danspace77.com/what-are-planetary-nebulae/
NAME: Abell 33, PN A66 33 and foreground star HD 83535.
WHAT IS IT?: Planetary nebula in a chance alignment with a star in the foreground.
HOW FAR AWAY IS IT?: Nebula is aproximately 2500 light years distant while star HD 83535 is roughly 869 light years or 240 parsecs away.
HOW BIG IS IT?: 4.5’x4.5’ arcminutes on the night sky.
APPARENT MAGNITUDE?: Nebula is around mag 13 while the foreground star HD 83535 is an apparent magnitude 7.2.
WHERE IS IT? (General): Constellation Hydra (The Water Snake) and the largest constellation.
WHERE IS IT? (Exact RA/DEC J2000): RA 9h 39m 4.14s / DEC -2° 50′ 22.55″.
ESO information release for this image: http://www.eso.org/public/usa/news/eso1412/
ESO image release for this image: http://www.eso.org/public/usa/images/eso1412a/
Ashland Astronomy Studio page on Star HD 83535: http://www.astrostudio.org/xhip.php?hip=47369
SIMBAD data page on Star HD 83535: http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HIP+47369