This is Messier 57, better known as the Ring Nebula (or NGC 6720). Located 2300 light years from Earth, the Ring Nebula lies in the Lyra constellation. Discovered in 1779 by Antoine Darquier de Pellepoix (and then again by Messier), this was the second planetary nebula ever found. At the center of the nebula lies a planet-sized white dwarf star currently burning at over 100,000 Kelvin. Around the star, in what appears to be a ring-like structure, is ionized gas which was ejected from the star over time. Astronomers question whether or not this “ring” is actually a ring at all; indeed, there is some observational evidence suggesting that the ejected gas may actually form a cylinder, and we are simply seeing through it from one end.
In the above image of the Ring Nebula, we can see the ejected ring (or cylinder) of gas—colored red, yellow, and green. We can also faintly see the white dwarf star at the center of this apparent ring. Note the rings coloring. The wavelengths of the emitted light get progressively longer the farther they are from the center—the outer rim being almost red. The diameter of the Ring Nebula is roughly one light year, which we can determine based on the dimensions of the above image and the known distance of the Ring nebula from Earth.
Frommert, Hartmut, and Christine Kronberg. "Messier 57." Students for the Exploration and Development of Space. 30 Aug. 2007. Accessed 3 Dec. 2010. <http://seds.org/messier/m/m057.html>.
Nemiroff, Robert and Jerry Bonnell. "M57: The Ring Nebula." Astronomy Picture of the Day. 15 Nov. 2009. Accessed 3 Dec. 2010. <http://antwrp.gsfc.nasa.gov/apod/ap091115.html>
|Right Ascension (J2000)||18:53:36|
|Declination (J2000)||+ 33:02:00|
|Filters used||blue(B), green(V), red(R), and clear(C)|
|Exposure time per filter||300 seconds|
October 28, 2010