Deneb

Deneb, designated Alpha Cygni, is the brightest star in the constellation Cygnus (the Swan) and one of the most prominent stars in the night sky, with an apparent magnitude around 1.25. It is a blue-white supergiant of spectral type A2 Ia. Deneb lies at a great distance from the Sun, commonly estimated at about 2,600 light-years (roughly 800 parsecs). Despite this distance, its intrinsic luminosity is immense, estimated at about 200,000 times that of the Sun. Its radius is of the order of hundreds of solar radii, and its surface temperature is around 8,500 K, giving it a characteristic blue-white hue.

In the sky, Deneb forms part of the Summer Triangle asterism, along with Vega and Altair. It marks the tip of the Swan’s tail in Cygnus, and its name derives from the Arabic word for tail. Deneb is catalogued in multiple star catalogs, including the Bayer designation Alpha Cygni, with several identifiers such as HD, HIP, and HR numbers used by professional catalogs. Because of its high luminosity and distance, Deneb is a subject of studies on massive star evolution and stellar atmospheres, and it is expected to end its life in a core-collapse supernova on timescales of several million years.