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Owl Nebula (NGC 3587)
Patrick J. Leugs

Owl Nebula

The Owl Nebula, also known as Messier Object M97, is a planetary nebula located in the Ursa Major constellation. A planetary nebula is a type of nebula created by the expanding glowing shell of a dying star. Once the gaseous shell has been knocked free, the core collapses and becomes extremely hot, giving off ultraviolet radiation that is caught by the shell, creating the luminous appearance. Although they are called "planetary" nebulas, the name is somewhat deceiving, as it was initially given to them in the 18th century due to their resemblance to giant planets when viewed through a small optical telescope. Formed approximately 6,000 years ago, the Owl Nebula is generally considered to be one of the more complex objects. The nebula gets its name from the two distinctive "eyes," a pair of similarly-sized darker areas that, together, create the illusion of an owl's face.

When viewed with red, blue, and green filters, the Owl Nebula takes on a predominantly dull green appearance, as seen above, due to the prominence of oxygen in the shell's composition. The edge of the nebula's shell, however, can be seen to have a slightly more reddish coloration, denoting the presence of hydrogen. The shell of the Owl Nebula seems to have a sort of "double edge" effect, appearing to be made of two separate shells or "bubbles." This is due to the fact that the Owl Nebula has a second bubble of lower ionization surrounding the first. Notably, a trio of bright stars can be seen within the nebula, the top one of the three being the core, while the other two may be closer to or farther from Earth than the nebula itself. The distance to the Owl Nebula is estimated to be and generally accepted as 2,600 light years, but its true distance is actually unknown. The estimated measurements have ranged greatly across the years, from 1,300 light years to as high as 12,000 light years (Messier Object 97). Having estimated a maximum angular size of approximately 3.4 arc minutes, I found that this corresponds to a linear size of approximately 2.5 light years.

References:

Owl Nebula - Wikipedia, the free encyclopedia. Wikimedia Foundation, Inc., 28 Feb. 2011. Web. 12 Apr. 2011. <http://en.wikipedia.org/wiki/Owl_Nebula>.

Plantary nebula - Wikipedia, the free encyclopedia. Wikimedia Foundation, Inc., 27 Mar. 2011. Web. 12 Apr. 2011. <http://en.wikipedia.org/wiki/Planetary_nebula>.

Frommert, Hartmut, and Christine Kronberg. Messier Object 97. N.p., 2 Sept. 2007. Web. 12 Apr. 2011. <http://seds.org/messier/m/m097.html>.

Right Ascension (J2000) 11:14:48
Declination (J2000) +55.01.00
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B, V, R, and C (60s x 5)
Date observed March 22, 2011 UT

 

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