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NGC 247 & M77
Melissa Burgess & Breanna Smith

NGC 247 M77
NGC247- Melissa Burgess M77- Breanna Smith

Both M 77 and NGC 247 are considered spiral galaxies. Spiral galaxies appear as flat white disks that have a yellowish bulge at their center. Inside of the disks are cool gasses and dust as well as hotter ionized gas. Additionally, spiral galaxies have beautiful spiral arms. Within the category of “spiral galaxy” are subcategories. M 77 is in the subcategory of barred spiral galaxy, meaning the galaxy has a bar of stars that cut across the center of the galaxy. NGC 247, on the other hand, is an intermediate spiral galaxy, which means it is between a barred and an unbarred spiral galaxy.

Messier 77 (M 77) is a barred spiral galaxy approximately 60 million light-years away. When first discovered, M 77 was described as a nebula. As the field of astronomy expanded and new discoveries were made, however, it was discovered that M 77 was actually a barred spiral galaxy. M 77 is unique in that it is utilized to study suppermassive black holes inside of active galaxies. The reason for this is that at the heart of M 77 is an active black hole that is approximately 15 million times the mass of the Sun. Due to M 77 being utilized to study suppermassive black holes inside of active galaxies, M 77 became one of the most well-studied and famous galaxies in the sky.

NGC 247 is classified as an intermediate spiral galaxy. It is, however, sometimes classified as a dwarf spiral galaxy. An intermediate spiral galaxy is defined as between a barred spiral galaxy and an unbarred spiral galaxy classification. NGC 247 is in the constellation Cetus, about 11.1 million light-years away, and is one of the closest galaxies in relation to us of the southern sky. The galaxy appears to be warmer in color, almost a pinkish-orange. This is due to the large amounts of hydrogen glowing around the galaxy’s component stars. This means there is active star formation going on in regions of the galaxy. An interesting thing to note about this galaxy is that there is a specific large void on one side. It contains older stars, but no younger blue ones.

While each galaxy is unique, M 77 and NGC 247 have a handful of similarities to one another. For starters, both galaxies are spiral galaxies. Additionally, both spiral galaxies are in the constellation Cetus. Finally, both M 77 and NGC 247 have active star formation occurring in the galaxy. This is due to the large amounts of hydrogen and helium in the galaxies.

While the two galaxies hold some similarities, they also hold some differences. For example, the galaxy M 77, otherwise known as Messier 77, is classified as a barred galaxy. It has clear spirals extending from the bulge. The galaxy NGC 427, however, is classified as in between barred and unbarred. It does not have as defined spirals as M 77. M 77 is significantly farther away, being 47 million light-years as compared to NGC 247 being 11.1 million light-years away from us. The galaxy M 77 has an active galactic nucleus which makes the center of the galaxy have a significantly larger luminosity than other galaxies, such as NGC 247.

References:

Crawford, Ken. NASA, NASA, 7 Dec. 2006, http://apod.nasa.gov/apod/ap061207.html. Accessed 15 Nov. 2016.

Guttridge, Nicky. Hubble Space Telescope, ESO, 28 Mar. 2013, https://www.spacetelescope.org/news/heic1305/. Accessed 15 Nov. 2016.

Hook, Richard. "The Dusty Disc Of NGC 247." ESO, ESO, 11 Mar. 2011, https://www.eso.org/public/usa/news/eso1107/. Accessed 15 Nov. 2016.

Wikipedia, Wikipedia, https://en.wikipedia.org/wiki/Messier_77. Accessed 15 Nov. 2016.

Wikipedia, Wikipedia, 6 Nov. 2016, https://en.wikipedia.org/wiki/NGC_247. Accessed 15 Nov. 2016.

 

Object NCG247 M77
Right Ascension (J2000) 00:47:08.5 02:42:40.07
Declination (J2000) -20:45:37 -00:00:48
Filters used B (Blue), C (Clear), R (Red), V (Green) B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B (200s); V and R (100s); C (60s) B (180s); V and R (90s); C (60)
Image dimension 1092x736 pixels; 23.66x15.95 arcminutes 519x298 pixels; 11.25x6.46 arcminutes
Date/time observed October 4, 2016, 08:20 UT OCtober 8, 2016, 07:31 UT

 

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