Daily Image
20-06-2007
A summer planetary nebula
| Submitter: | Albert van Duin |
| Description: | The Dumbbell Nebula (also known as Messier 27, M 27, or NGC 6853) is a planetary nebula (PN) in the Vulpecula constellation, at a distance of about 1360 light years. This object was the first planetary nebula to be discovered; by Charles Messier in 1764. At its brightness of visual magnitude 7.5 and its diameter of about 8 arcminutes (1/4 of the apparent Moon diameter), it is easily visible in binoculars, and a great observing target in amateur telescopes. This PN appears to be shaped like an prolate spheroid and is viewed from our perspective along the plane of its equator. In 1992, Moreno-Corral et al. computed that the rate of expansion in the plane of the sky of this PN was no more than 2.3 arcsecond per century. From this, an upper limit to the age of 14,600 yr may be determined. Is 1970, Bohuski, Smith, & Weedman found an expansion velocity of 31 km/s. Given the semi-minor axis radius of 1.11 (+0.13 -0.17)light years, this implies that the kinematic age of the PN is 10,700 (+1,300 -1,600) years old. The central star, a white dwarf, is estimated to have a radius which is 0.055 ± 0.02 Solar radius which gives it a size larger than any other known white dwarf.[2] The central star mass was estimated in 1999 by Napiwotzki to be 0.56 ± 0.01 Solar mass. Source: http://en.wikipedia.org/wiki/Messier_27 The image was made in Beilen on May 17, 2007, it is a 30 minute exposure at 1600 ISO with a modified Canon 350D and a 20cm ASA Astrograph. http://www.astropix.nl |
| Copyright: | Albert van Duin |
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