2 Cygni

2 Cygni (2 Cyg) is a star in the constellation Cygnus. Its apparent magnitude is 4.98, and it is located approximately 839 light years away from Earth.

References

Albireo

Albireo (β Cyg, β Cygni, Beta Cyg, Beta Cygni) is the fifth brightest star in the constellation Cygnus. Although it has the Bayer designation beta, it is fainter than Gamma Cygni, Delta Cygni, and Epsilon Cygni. Albireo appears to the naked eye to be a single star of magnitude 3 but through a telescope, even low magnification views resolve it into a double star. The brighter yellow star (actually itself a very close binary system) makes a striking colour contrast with its fainter blue companion star.

Double star

Albireo is about 430 light-years (130 pc) away from the Earth. When viewed with the naked eye, it appears to be a single star. However, in a telescope it readily resolves into a double star, consisting of Albireo A (amber, apparent magnitude 3.1), and Albireo B (blue-green, apparent magnitude 5.1). Separated by 35 seconds of arc, the two components provide one of the best contrasting double stars in the sky due to their different colors. It is not known whether the two components are orbiting around each other in a physical binary system. If they are, their orbital period is probably at least 100,000 years.

32 Cygni

32 Cygni (32 Cyg, Omicron² Cyg, ο² Cyg) is the Flamsteed designation for a binary star system in the Cygnus constellation. It is a 4th magnitude star, which can be seen with the naked eye under suitably dark skies. Parallax measurements give an estimated distance of 1,100 light-years (320 parsecs) from the Earth. However, Schröder et al. (2007) suggest the actual value, after correcting for Malmquist bias, may be closer to 1,174 light-years (360 parsecs).

The primary component in this system, 32 Cygni A, has a stellar classification of K4–5 Ib, indicating that it is a lower luminosity supergiant star. Its effective temperature of 3,840 K lies in the range for K-type stars, giving it an orange hue. This star has more four than times the mass of the Sun and the outer envelope has expanded to about 184 times the Sun's radius. It is radiating 6,600 times the luminosity of the Sun.

The companion star, 32 Cygni B, is smaller than the primary, with four times the Sun's mass and three times the Sun's radius. It has a much higher effective temperature of 16,200 K and is radiating over 300 times the Sun's luminosity. This star has the blue-white hue of a B-type star, with a stellar classification of B6–7 IV–V. The luminosity class 'IV–V' fits a star that has nearly exhausted the hydrogen at its core and begun to evolve off the main sequence to become a subgiant star.