Deneb

Deneb is a blue-white supergiant star in Cygnus and the brightest star in the Northern Cross. Its great luminosity makes it visible across an immense distance.

Stellar classification: A system that groups stars by spectral features and luminosity. Deneb’s spectral type and luminosity class describe its temperature and supergiant status.
Cygnus: A northern constellation whose brightest star is Deneb. Deneb marks the tail of this constellation’s swan figure.
Stellar evolution: The sequence of physical changes a star undergoes from formation to its endpoint. Deneb’s supergiant phase reflects the late evolution of a massive star.
Cygnus X-1: A binary system in Cygnus containing a black hole accreting matter from a massive companion star. This famous Cygnus system provides a nearby landmark in the constellation Deneb anchors.
Supergiant: A highly luminous star with an extended atmosphere and large radius. Deneb’s luminosity class identifies it as a supergiant nearing the end of its stellar life.
Northern Cross: An asterism of five bright stars forming a cross within Cygnus. Deneb forms the top of the cross and is its brightest star.
Alpha Cygni variable: A luminous supergiant whose brightness varies irregularly through pulsations and atmospheric changes. Deneb’s small, irregular brightness changes place it in this variable-star class.
Parallax: The apparent shift of a nearby object against distant background objects as the viewpoint changes. Parallax measurements help constrain Deneb’s distance, which remains difficult to determine precisely.
Blue-white star: A star whose surface temperature gives it a blue-white appearance. Deneb’s hot surface produces its blue-white color.
Summer Triangle: An asterism formed by the bright stars Deneb, Vega, and Altair. Deneb is one of the triangle’s three defining stars.

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Blue supergiantBroader topic: Deneb illustrates the enormous luminosity of a relatively distant supergiant.