Deneb
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Deneb (α Cyg / α Cygni / Alpha Cygni) is the brightest star in the constellation Cygnus and one of the brightest stars in the night sky, with apparent magnitude 1.25.
It is, or has been, known by a number of other traditional names, including Arided, Aridif, but today these are almost entirely forgotten.
Deneb's absolute magnitude is −7.2, placing it among the most luminous stars known.
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Distance and physical characteristics
Deneb's exact distance from the Earth is a matter of some dispute; most equally distant stars are not visible to the naked eye, and may be identified only by catalog numbers, if they are known at all. Figures from 1600 to 3200 light years appear on various online sources. It should be noted that determination of distances at this range is very difficult because stars with such distances have negligible parallax. Moreover, the uncertainty about distance makes determining its other properties similarly imprecise.
Estimates for Deneb's luminosity range from about 60,000 times the brightness of our Sun (if Deneb is 1600 light years away) to 250,000 times the Sun's brightness (if 3200 light years away). If Deneb were a point source of light at the Sun's distance from Earth, it would be far brighter than most industrial lasers; It generates more light in one day than the Sun does in 140 years.
The star appears to have a diameter about 200 to 300 times that of the Sun; if placed at the center of our Solar System, Deneb would extend to the orbit of the Earth. A star of spectral type A2Ia, Deneb has a surface temperature of 8,400 kelvin. Deneb's mass is estimated at 20 to 25 solar masses. As a blue giant, its high mass and temperature means the star will have a short lifespan and will probably become a supernova within a few million years.
Name
The name is from dheneb, the Arabic for "tail", from the phrase ذنب الدجاجة <eth>anab ad-dajājah, or "tail of the hen". Similar names were given to a at least seven different stars, most notably Deneb Kaitos, the brightest star in the constellation Cetus, and Denebola, the second brightest star in Leo.
Mythology
In the Chinese love story of Qi Xi, Deneb marks the magpie bridge across the Milky Way which allows the separated lovers Niu Lang (Altair) and Zhi Nü (Vega) to be reunited on one special night of the year in late summer. In other versions of the story Deneb is a fairy who acts as chaperone when the lovers meet across the bridge of magpies.
External links
- Info from Star of the Week (http://www.astro.uiuc.edu/~kaler/sow/deneb.html)
- Info from St. Cloud State University (http://domeofthesky.com/clicks/deneb.html)ca:Deneb
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