- Omicron2 Cygni Group
The Omicron2 Cygni Group is an asterism located in the constellation Cygnus just to the east of the star Deneb (α Cygni). In my image, it is the group of 7 stars in the upper right corner making a somewhat crooked cross with the bright orange star ο2 (HD 192909) at the top end. This shape also looks like a crooked version of Cygnus itself, with ο2 in the place of Deneb. There appears to be no physical relationship among the stars in this group. ο2 lies at a distance of 1052 LY, while the second brightest star in the group (the blue-white HD 192802 opposite ο2 in the "cross") lies at a distance of 777 LY. While not a true cluster, long-exposure images show that ο2 is involved in nebulosity illuminated by reflected light from the star (this doesn't show up in my image). ο2 itself is an eclipsing binary (a large orange class K giant orbited by a small blue-ish class A star) with a period of 3.15 years.
In the opposite corner of my image is a beautiful optical triple star, the brightest component of which is ο1 Cygni. ο1 (HD 192577) is a bright (visual magnitude 3.8) orange class K giant. Lying to the lower right of ο1 is the magnitude 4.8 HD 192514 (30 Cygni), a blue-white class B main sequence star. The color difference in this pair of stars is visible in binoculars or a small telescope, which makes this pair a fine object for viewing. Just to the left of ο1 in my image is the smaller HD 192579, a blue-white class B subgiant with a visual magnitude of 7.01. The distances to ο1, 30 Cygni, and HD 192579 are, respectively, 882, 615 and 1359 LY. ο1 is itself an eclipsing binary system with a period of 10.42 years.
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