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Astr111 Photography Projects, Fall 2009

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Little Dumbbell Nebula, Candace Price

Little Dumbbell Nebula

Most commonly recognized by the name Little Dumbbell Nebula, M 76 has also been called Cork Nebula, Butterfly Nebula, and Barbell Nebula. M76 was first discovered by Pierre Méchain on September 5, 1780, who reported it to Charles Messier. Charles Messier observed Little Dumbbell on October 21, 1780, determined its position and added it to his catalog. M76 is one of the faintest Messier Objects located in the eastern part of constellation Perseus, which is visible in the northern hemisphere during the winter months.  The little Dumbbell is one of only four planetary nebulae in Messier’s catalog. In 1918 Herber D. Curtis was the first to correctly classify M 76 as a planetary nebula; Mechain had found it to be a nebula without stars, Messier had thought it to be composed of small stars with some nebulosity. Messier had most likely been confused by the stars in the background and foreground of the nebula. Though there are only four planetary nebulae in Messier’s catalog, astronomers have since estimated that there are between, 20,000 to 50,000 planetary nebulae in our galaxy alone. A planetary nebula forms from a dying star that can no longer support itself and the gravity of the outer material condenses and heats up at the center, then the heat causes the outer half of the star away. The gas expands significantly more rapidly to form the lower surface brightness "wings" of the butterfly. This ring seems to expand at about 42 km/sec along the axis perpendicular to this plane.

The distance of the Little Dumbbell Nebula is poorly known to be between 1,700 and 15,000 light years. Since the distance to the object is somewhat uncertain the linear size of the M76 is also to estimate as well between .756 and .667 light years. Its appearance in many ways resembles the earlier found Dumbbell Nebula M27. The main body, also known as the cork is a bright and slightly elliptical ring that can be seen from only a few degrees off its equatorial plane. In the Little Dumbbell Nebula photo we see a glowing bright cork that yellow green color and red near the two ends on the top and the bottom. The sides of the object have elliptical rings that are green colored and expand out resembling elephant ears. In this image we see above of the Little Dumbbell Nebula the original star that caused the planetary nebula is still visible at the center of the object, most likely the material was blown away from the star in two stages causing the cork shape and then the ring shapes on the sides. The star in the remaining star in the center heats up and causes the fluorescent glow seen above, the glowing red and green color shows that object contains hydrogen, and helium gases.

References:

National Optical Astronomy Observatory."A Planetary Nebula Sampler" <http://www.noao.edu/jacoby/pn_gallery.html>

Frommert, Hartmut and Kronberg, Christine. "M 76."Little Dumbbell Nebula" <http://www.seds.org/messier/m/m076.html>

Right Ascension (J2000) 01:42:18
Declination (J2000) +51:34:00
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter 60 seconds in B,V,R, and C
Date observed

November 11, 2009 (BVRC)