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NGC 2336

NGC 2336 lies in Camelopardalis, a constellation next to Polaris. Unlike Polaris which is a single star, NGC 2336 is a galaxy, a collection of stars, dusts and other celestial objects bound together by gravity. It's 32.2 megaparsec away from us (Gusev 2003), which translates into a distance of 105 million light years, or 617 million trillion miles (6.17*10^20 miles), about 242,000 times farther away than Polaris. There are three common types of galaxies: spiral, elliptical and irregular galaxy. NGC 2336 is a barred spiral galaxy, characterized by its apparent, highly developed spiral arms and a bar-shaped structure at its center. Spiral galaxy in general has relatively large size and is rich in gas and dust, thus experiencing active star formation, whereas the size of elliptical galaxy can vary a lot and they are very poor in gas. Elliptical galaxy has very little star formation and their stellar populations are generally old. Irregular galaxy tends to be the smallest of the three, possessing both young and old stars. Among the three, both elliptical and irregular galaxy lack highly ordered structures. On appearance, elliptical galaxy looks mostly orange or yellow while irregular and spiral galaxy have blue stars and pink nebula, signaling active star formation.

In the picture taken, spiral arms of NGC 2336 have a purple tinge which possibly results from a mix of blue and pink. Pink regions are likely to be emission nebula whose hydrogen atoms have been ionized by newborn stars and emit at Balmer series. The blue light are most likely emitted by massive, young O stars. Both features indicate that the galaxy is rich in gas and has active star formation.

From the images obtained, the length of the major and minor axis of the galaxy were measured to be 269 and 133 respectively in pixel unit. Provided that the pixel scale of our CCD is 1.18 arcsecond per pixel, the major and minor axis of galaxy were converted into angular size of 317 and 157 arcsecond respectively. According to its distance cited above, its major axis has a linear size of 1.60*10^(5) l.y. and its minor axis 7.89*10^(4) l.y. Since the east side(the left side in the picture) of the galaxy inclines away from us (Keel 1993), the inclination angle can be calculated with arccosine, which turns out to be 60.4 degrees, which is close to the inclination angle found in literature, 57.25 degrees (Gusev 2003). Assuming NGC 2336 has a circular shape, it has a diameter of 1.60*10^(5) l.y., while the literature value is 2.12 * 10^(5) l.y. A detailed brightness profile was fitted for the bulge using Logger Pro. An Sersic profile curve fit was obtained, I(r)=Ie*exp[-b*((r/Re)^(1/n)-1)), in which Ie=77.38, b=6.223, Re=348 (in pixel units), n=3.987. With n very close to 4, the bulge seems to be well described by the de Vaucouleurs profile, which is generally a good description of elliptical galaxy. In this case, it indicates that the bulge of NGC 2336 is made up of old stellar population, similar to the stellar composition of elliptical galaxy. This is also supported by the yellow, orange glow of the bulge in the picture, indicating the presence of low-mass, long-lived stars. Below is the screen shot of the curve fit described above performed by Logger Pro.

Data Reduction: Images were calibrated against Bias, Dark and Flat images taken on the same day. All images from each individual filter were combined under "auto-star matching" alignment mode, "Sigma Clip" combine mode in 16-bit Int FITS format. For color combine, values RVB was set to 4.1:5:34, with luminance weight set to 15%. Color saturation is 235%.

References:

Gusev, A. S. "Structure and Stellar Population of Ringed Barred Galaxy NGC 2336." Structure and Stellar Population of Ringed Barred Galaxy NGC 2336. Astronomy and Astrophysics, Oct. 2003. Web. 04 May 2015. http://adsabs.harvard.edu/abs/2003A%26A...410..117G

Keel, William C. "Kinematic Regulation of Star Formation in Interacting Galaxies." Kinematic Regulation of Star Formation in Interacting Galaxies. Astronomical Journal, Nov. 1993. Web. 04 May 2015. http://adsabs.harvard.edu/abs/1993AJ....106.1771K

Right Ascension (J2000) 07:27:04
Declination (J2000) +80:10:40
Filters used B (Blue), C (Clear), R (Red), V (Green)
Exposure time per filter B (90s x 33), V (90s x 10), and R (90 x 12s ); C (90s x 26)
Image dimension 876x572 pixels; 17.2x11.2 arcminutes
Date/time observed March 16, 2015, 02:47:08 to 05:15:08 UT

 

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