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Wildrik Botjes Planetarium
Physics & Astronomy Department

Astr110 Photography Projects, Fall 2007

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Planetary Nebula M97 (NGC 3587), Kris Nivens

Owl Nebula

The Owl Nebula is a planetary nebula located in the constellation Ursa Major. It was discovered in 1781 by Pierre Mechain, but was not named the Owl until 1848. It is one of only four planetary nebulae which Charles Messier recorded in his catalog.

The nebula as represented in this image is greenish and faint, which is characteristic of M97; this indicates that it is primarily composed of oxygen. According to Frommert and Kronberg, it is "significantly brighter visually... than photographically." The Owl is described as a "cylindrical torus shell", which simply means that the two dark spots are less dense parts of the nebula. The distinct apple-core shape of the nebula could be due to rotations of the central star, which spin the gas into two dense ends. M97 is a very gaseous nebula and its distance is uncertain; therefore its linear size can only be approximated. According to Frommert and Kronberg, the Owl Nebula is about 2600 light years away. With that value, my estimate gives it a linear size of about 2.14 x 2.14 light years.

References:
Frommert, Hartmut and Kronberg, Christine. "Messier Object 97." Students for the Exploration and Development of Space. <http://www.seds.org/messier/m/m097.html>

Frommert, Hartmut and Kronberg, Christine. "Planetary Nebulae." Students for the Exploration and Development of Space. <http://www.seds.org/messier/planetar.html>

Right Ascension (J2000) 11:14:48
Declination (J2000) +55:01:00
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 3.0 sec in BVRC
Date observed

October 23 , 2007 (CBR)
November 2, 2007 (V)