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Astr110 Photography Projects, Summer, 2009

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Little Ghost Nebula Jason Colegrove

Little Ghost

The target I chose to photograph is a planetary nebula called the Little Ghost Nebula. It was initially discovered by William Herschel in the 18th century. Due to its ring and faintness the nebula received the name of Little Ghost. This planetary nebula is not related to the formation of planets as one might think. In fact this image shows a star much like our sun at the end of its life span. The outer layers have expanded while the core has shrunk into a white dwarf. The white dwarf which is clearly visible in the middle of the ring emits strongly at UV wavelengths greatly contributing to the nebula's luminescence. The nebula ring consists of dust and ionized gases such as oxygen, hydrogen, and nitrogen. Astronomers value this object because it gives us a picture of what our sun could possibly do in about 5 billion years. The Little Ghost Nebula is approximately 2000 light-years from earth located in the constellation, Ophiuchus.

Viewing the image above one can see the bright core of the star at the center of nebula. The faint yellow-green cloud at the outer edge of the nebula is ionized nitrogen, while the brighter more dense yellow ring is comprised of nitrogen and oxygen. This cloud is formed by the expansion of the star and then its collapse. Images from the Hubble Telescope let the observer do a better job at discerning the differences in these ionized gases. The angular size is approximately 1.03 arcminutes and the linear size is about .60 light years.

References:

Nemiroff, Robert and Jerry Bonnell.. "Astronomy Picture of The Day". http://apod.nasa.gov/apod/ap021108.html

Space.com Staff. "New Hubble Image of Little Ghost Nebula." http://www.space.com/scienceastronomy/little_ghost_021107.html

Right Ascension (J2000) 17:29:18.00
Declination (J2000) -23:46:00.0
Filters used blue(B), green(V), red(R) and clear(C)
Exposure time per filter 5x60 seconds in BVR and 5x60 seconds in C
Date observed

June 30, 2009