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The Brightness or Luminosity of Deneb is 196,000 L. It is one of the most luminous stars in the Milky Way and ranks 19th out of 100 thousand million other stars.

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The Temperature of Deneb is 8,525 K, which is measured in Kelvin.

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Deneb or Alpha Cygni (Alp Cyg) is the brightest naked eye star in the constellation Cygnus. With an apparent magnitude of 1.25v, Deneb is the 19th brightest star in the entire sky (see: 50 Brightest Stars ). Its absolute magnitude is -8.73 and its distance is 3230 light years. The Equinox J2000 equatorial coordinates are RA = 20h 41m 25.9s, Dec = +45° 16' 49".

Deneb has a spectral type of A2Ia, a surface temperature of 8525° Kelvin and a luminosity 54,000 times the Sun. It has a mass of 20 solar masses and a diameter 110 times the Sun.

The image above shows the uncropped view of Deneb (North is up) through the Takahashi E-180 Astrograph.

Deneb along with Altair and Vega

form the vertices of the Summer Triangle. With andabsolute magnitude of -7.0, Deneb is among the most intrinsically bright stars known, with an estimated luminosity nearly 60,000 times that of the Sun. Its exact distance is uncertain, which makes determining many of Deneb's other properties similarly imprecise. However, the uncertainty was dramatically reduced upon analysis of the Hipparcos Data Reduction in 2007. One 2008 study puts the most likely distance at 1,550 light-years, with an uncertainty of approximately 10%. The reduced parallax uncertainties do not rule out a distance as close as 1,340 light-years or as far as 1,840 light-years. It is the farthest-known first-magnitude star from Earth.

Based on its temperature and luminosity, and also on direct measurements of its tiny angular diameter (a mere 0.002 arcseconds), Deneb appears to have a diameter of about 110 times that of the Sun; if placed at the center of our Solar System, Deneb would extend halfway out to the orbit of the Earth and would appear xxx ° in apparent diameter (the Sun's apparent diameter is 0.5°). Alpha Cygnii is one of the largest white stars known.

As a blue-white supergiant (spectral type A2Ia), Deneb's high mass (20 solar masses) and temperature (8,400° Kelvin) mean that the star will have a short lifespan and will probably go supernova within a few million years. It has already stopped fusing hydrogen in its core. The star was probably an O class star during its main sequence lifetime and is now probably expanding into a red supergiant like Mu Cephei. As it expands, it will go through the F, G, K and M spectral types.

Deneb's solar wind causes it to lose mass at a rate of 0.8 millionth of a solar mass per year, a hundred thousand times the flow rate from the Sun. It is the prototype of a class of variable stars known as Alpha Cygni variables. Its surface undergoes non-radial fluctuations which cause its brightness and spectral type to change slightly.

The description above is based on the Deneb entry in Wikipedia. For more information about Deneb, see Stars (Jim Kaler).

Technical Details

Object: Deneb

Other Names: Alpha Cygni, HR7924, HD197345, HIP102098

Object Type: bright star

Object Data: Apparent Magnitude = 1.25v, Absolute Magnitude = -8.73, distance = 3230 light years

Object Position (Equinox J2000): RA = 20h 41m 25.9s, Dec = +45° 16' 49", Constellation = Cygnus

Date/Time: 2011 Oct 21 at 03:50:28 UTC

Location: Bifrost Astronomical Observatory, Portal, AZ

Mount: Astro-Physics 1200GTO

Telescope: Takahashi Epsilon 180 Hyperbolic Astrograph

Camera: Canon EOS 550D (Rebel T2i) (modified with a Baader UV/IR filter)

Field of View: 1.70° x 2.56° at 1.7 arc-sec/pixel (web version: 10.0 arc-sec/pixel)

Exposure: 2 x 300s, f/2.8, ISO 800

File Name: Deneb-01w.jpg

Processing (Adobe Camera Raw): Graduated Filter, Vignetting Correction, Noise Reduction, White Balance, Curves

Processing (Photoshop CS5): Average Images, Curves, Noise Reduction

Original Image Size: 3454 × 5179 pixels (17.9 MP); 11.5" x 17.3" @ 300 dpi

Rights: Copyright 2011 by Fred Espenak. All Rights Reserved. See: Image Licensing.

AstroPixels Links

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Deneb or Alpha Cygni (Alp Cyg) is the brightest naked eye star in the constellation Cygnus. With an apparent magnitude of 1.25v, Deneb is the 19th brightest star in the entire sky (see: 50 Brightest Stars ). Its absolute magnitude is -8.73 and its distance is 3230 light years.

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Deneb is 2,616 Light Years away from Earth. Here is a video if you were to travel through the Milky Way to Deneb.

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Star Travel to Deneb through the Real Milky Way

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Estimated Age of  Deneb & Expected Life Left

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Estimated Age of  Deneb & Expected Life Left

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The Age of Deneb is about 10.01 million years old and is said to have 1 million years left to live.

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Deneb is located in the Supergiants section and in the Top-Left Corner in Spectral class A2 la.

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The Mass of Deneb is 20 solar masses. The diameter is 110 times the sun. This is Deneb compared to the Sun.

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Deneb is a Supergiant and is a white/blue color which means it is in the Massive Star life cycle.

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Deneb, Alpha Cygni, is the brightest star in Cygnus constellation and the most distant of all first magnitude stars.

Deneb is a luminous blue supergiant. It is one of the stars that form the Summer Triangle, along with Altair in Aquila constellation and Vega in Lyra.

Deneb is also the brightest star of the Northern Cross, another prominent summer asterism found in the northern skies.

Deneb has an apparent magnitude of 1.25 and is located at distance of 3,550 light years from Earth. It is the largest and most distant of the three bright stars that form the Summer Triangle, and also by far the most luminous, with an absolute magnitude of -8.38 and luminosity about 196,000 times that of the Sun. The star has a surface temperature of 8,500 K.

Deneb is the 19th brightest star in the sky and the easiest of the three vertices of the Summer Triangle to locate because it is part of the Northern Cross.

Cygnus constellation itself is sometimes referred to as the Northern Cross, much like Crux in the south is known as the Southern Cross, even though the constellations contain more stars than those forming the asterisms.

The Northern Cross is by far more distinctive and larger than its southern counterpart.

The name Deneb is derived from the Arabic dhaneb, which means "the tail." Alpha Cygni marks the tail of the Swan constellation, with the bright double star Albireo, Beta Cygni, marking the bird's beak. A notable deep sky object, the black hole Cygnus X-1, is located near the middle of the swan's neck.

Names similar to Deneb were given to a number of bright stars that mark the tail of the animal their constellations represent, from Deneb Kaitos in Cetus (the Whale) and Deneb Algiedi in Capricornus (the Goat) to Denebola, the second brightest star in Leo (the Lion) constellation.

FACTS

Deneb belongs to the spectral class A2 Ia. It is a blue-white supergiant, and one of the most luminous stars known. Among the 30 brightest stars in the sky, Deneb is by far the most distant, by a factor of almost 2. The star's estimated diameter is 100 to 200 times that of the Sun, which makes it one of the largest A-type stars known.

Deneb is the prototype of a class of stars known as Alpha Cygni variables. These stars exhibit non-radial fluctuations of the surface and as a result their spectral type and luminosity change slightly.

The star has a mass about 19 times that of the Sun. It will have a relatively short life and probably go out in a supernova explosion within the next few million years. In its current phase, Deneb is likely expanding into a red supergiant. It is losing mass at a rate of 0.8 millionth of a solar mass every year as a result of a strong stellar wind.

Cygnus constellation represents the Swan. In Greek mythology, the constellation represents Zeus, who turned himself into a swan to seduce Queen Leda of Sparta. In another version of the tale, Zeus turned himself into a swan to trick the goddess Nemesis into giving him shelter. The two had an affair and Nemesis produced an egg which was then given to Leda by Hermes. It was said that Leda's daughter Helen hatched out of the egg. She later became famous as Helen of Troy.

In the better known version of the myth, Zeus seduced Leda, who was married to King Tyndareus, and she gave birth to two sets of twins: Helen and Clytemnestra, and Castor and Polydeuces. Helen and Polydeuces were the immortal children of Zeus, and Clytemnestra and Castor were Tyndareus' children and therefore mortal. The twins Castor and Polydeuces are represented by Gemini constellation, where the two brightest stars are named after them. Polydeuces is usually better known by his Latin name, Pollux.

Deneb - Alpha Cygni
Constellation: Cygnus
Location: 20h 41m 25.9s (right ascension), +45°16'49" (declination)
Spectral class: A2 Ia
Visual magnitude: 1.25
Absolute magnitude: -8.38
Mass: 19 ± 4 solar masses
Radius: 203 ± 17 solar
Luminosity: 196,000 ± 32,000 solar
Temperature: 8,525 ± 75 K
Distance: 3,550 light years (802 parsecs) ???
Variable type: Alpha Cygni
Designations: Deneb, α Cygni, 50 Cygni, Arided, Aridif, Gallina, Arrioph, HR 7924, BD +44°3541, HD197345, SAO 49941, FK5: 777, HIP 102098

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Deneb, Alpha Cygni, is the brightest star in Cygnus constellation and the most distant of all first magnitude stars. Deneb is a luminous blue supergiant. It is one of the stars that form the Summer Triangle, along with Altair in Aquila constellation and Vega in Lyra.

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#1: Deneb is known as the head of the Northern Cross.

#2: A person named Claudius Ptolemy discovered Deneb in the 2nd century.

#3: Deneb is almost 200 times as big as the Sun and if it was placed where the sun is, it would reach the orbit of the Earth.

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Deneb is made out of the following elements, oxygen, carbon, hydrogen, helium, sulfur, calcium, yttrium, strontium, zirconium, barium, lanthanum, and europium.

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This is Claudius Ptolemy, the man who discovered Deneb.