The Dumbbell Nebula (Messier 27) taken from Al Sadeem Observatory on the night of August 18-19, 2018 using GSO RC8 Telescope and ZWO1600MC-Cool CMOS Camera. Total exposure time is 51 minutes, Image stacking and processing were done in Pixinsight and Photoshop.
ABOUT THE NEBULA
The Dumbbell Nebula (also known as Messier 27, NGC 6853) is a well-known planetary nebula situated about 1200-1360 light-years away from Earth (approximate distance uncertain) in the constellation of Vulpecula (the fox).
It was the first planetary nebula observed and catalogue by French astronomer Charles Messier on July 12, 1764; described as an “oval nebula without stars”. As seen in visible spectrum, its colorful prolate spheroid shape resembles a dumbbell (as portrayed by English astronomer John Herschel), an apple core or an hourglass, giving its designated name.
Such planetary nebulae form when low-mass stars like our Sun (particularly stars with stellar mass of less than 8x solar mass) reaches the end of its red giant stage when nuclear fusion ceases, expelling its outer layers and creating a shell of ionized gases being illuminated with a remnant white dwarf about the size of Earth at the center. This will be somewhat the Sun’s ultimate fate after 5-6 billion years.
In this planetary nebula, the surrounding nebula glows through absorption and re-emission of the high energy radiation emitted by the central white dwarf star. The presence of doubly-ionized oxygen atoms gives the bluish-greenish color in the nebula’s center region. The central white dwarf star shines at magnitude 13.5, has a surface temperature of about 85,000 K, and with radius of about 0.055 ± 0.02 solar radii, the largest known of its kind.
With an apparent magnitude of +7.5 the faint grayish lobe-shaped figure might be seen using 10×50 binoculars and small telescopes, making it one popular target for amateur astronomers. The central white dwarf star may be resolved using bigger aperture telescopes (about 8” and above) and long-exposure color astrophotography.
Messier 27 can be found within the region of sky bounded along the Summer Triangle asterism, somewhere in between the two bright stars Deneb (in Cygnus) and Altair (in Aquila). Under clear, dark skies, it is located near the orange giant γ Sagittae, as shown in the figure below.
REFERENCES
Benningfield, D. 2014, July 12). Dumbbell Nebula. StarDate Online (Retrieved from https://stardate.org/radio/program/dumbbell-nebula-0
Dumbbell Nebula – Messier 27 (2014, July 6). Constellations: A Guide to the Night Sky. Retrieved from http://www.constellation-guide.com/dumbbell-nebula-messier-27/
Messier 27: Dumbbell Nebula (2015, April 21). Messier Objects: Guide to the Bright Galaxies, Nebulae and Clusters Listed in the Messier Catalogue. Retrieved from http://www.messier-objects.com/messier-27-dumbbell-nebula/
Plotner, T. (2016, November 21). Messier 27 – The Dumbbell Nebula. Retrieved from https://www.universetoday.com/33035/messier-27-dumbbell-nebula/