30 Cygni is a class A5III (white giant)

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Cygnus. Its apparent magnitude is 4.83 and it is approximately 610 light years away based on parallax. The Bayer letter ο (omicron) has been variously applied to two or three of the stars 30, 31, and 32 Cygni. 30 Cygni has sometimes been designated as ο¹ Cygni with the other two stars being ο² and ο³ respectively. For clarity, it is preferred to use the

Flamsteed designation A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the modern constellations visible from southern England. They are named for John Flamsteed who first used them while co ...

30 Cygni rather than one of the Bayer designations. 30 Cygni is about six arc-minutes from 31 Cygni A and seven arc-minutes from 31 Cygni B. That pair is known as ο¹ Cygni, while ο² Cygni is a degree away. Both ο¹ and ο² are 4th magnitude stars.

References

{{Stars of Cygnus Cygnus (constellation) A-type giants Cygni, 30 Durchmusterung objects 099639 7730 192514