The third star of the Summer Triangle, and the Fifty-Third star of the Nautical Almanac, is the massive white supergiant Deneb.
"Deneb" (in Arabic "Dhanab") means "Tail" and refers to the position of this star at the tail of the constellation Cygnus The Swan. "Deneb" was once the name applied to any "tail" star (such as "Deneb Kaitos" The Tail of The Whale of the constellation Cetus). Most of the other Denebs have been given alternate names to reduce misidentifications in the scientific community.
Deneb is also named Alpha Cygni, because it is Cygnus' brightest star. And although it is only the 19th brightest star as seen from Earth, Deneb may in fact intrinsically be the brightest star that we can see. The absolute brightness of Deneb is an unanswered question in part because Deneb's distance is very uncertain. Deneb's distance from the Sun has been estimated to be anywhere from 1,600 light years to 7,400 light years away (equal to 44,400,000,000,000,000, or forty four quadrillion four hundred trillion miles!). 3,200 light years is the most commonly accepted figure. Even at its estimated closest, Deneb is still a vast distance from Earth, and yet it is still a First Magnitude star. And that is twice as true at twice that vast distance. Double that and more, and Deneb is brighter still.
Deneb is estimated to be 100,000 to 200,000 times as
luminous as the Sun, maybe more, easily matching or handily beating out
Rigel's 120,000 rating on the brightness scale. Rigel is only 864 light
years from Earth, a mere fraction of Deneb's distance, so Rigel appears
brighter to us, but put Rigel at Deneb's distance and their rankings as
First Magnitude stars would likely be reversed. Deneb's extraordinary
light can be seen in the photograph, where it illumines other stars.
Just for comparison, of the five brightest stars in our sky, Sirius, Canopus, Alpha Centauri, Arcturus and Vega, only Canopus lies more than 40 light years away (74). Alpha Centauri is just 4.3 light years away, and Sirius just eight.
Deneb is 20 times the mass and 220 times the radius of the Sun. Were it placed in the center of our Solar System, Deneb's surface would touch the Earth. It burns at 15,000 degrees F. Deneb's solar wind (the force with which it burns off mass) is 100,000 times that of our Sun. Deneb loses the mass of the Earth once every 500 years.
Deneb is just ten million years old, but with its prodigious energy output, Deneb may be leaving its Main Sequence. There is a possibility that, given its mass and size, Deneb may blow off enough stellar material to stabilize as a smaller, dimmer star, but there is an equal chance that Deneb could supernova. Astronomers are fascinated by either possibility, given Deneb's extraordinary properties. Deneb, of course, could have exploded on the day the Roman Empire fell and we wouldn't know about it for thousands of years yet. Remember that because light only travels at a set speed (even if it is the fastest thing we know) when we look at Deneb, because we are unsure of its distance, we may be looking back in time anywhere from the time of the Huns to the building of Solomon's Temple back to the first crossing of the Bering Strait by Asians. To study the stars is to time-travel.
Deneb is popular in science fiction, a favored location in Isaac Asimov's stories, the television show Babylon 5, and especially in Star Trek.
In "The Trouble With Tribbles", a Klingon compares Captain Kirk to a "Denebian Slime Devil," a greenish, multieyed creature of unpleasant provenance. In "I, Mudd", the space freebooter Harry Mudd has the following conversation with Mr. Spock:
Mudd : Do you know what the penalty for fraud is on Deneb 5?
Spock : Guilty party has his choice. Death by electrocution, death by gas, death by phaser, death by hanging, death by . . .
Mudd : The key word in your entire peroration, Mr. Spock, was . . . d-d-d-DEATH.
Scientists doubt that there really are any Denebians, but if they do exist, I want the Coppertone and Ray-Ban concession!
"Deneb" (in Arabic "Dhanab") means "Tail" and refers to the position of this star at the tail of the constellation Cygnus The Swan. "Deneb" was once the name applied to any "tail" star (such as "Deneb Kaitos" The Tail of The Whale of the constellation Cetus). Most of the other Denebs have been given alternate names to reduce misidentifications in the scientific community.
Deneb is also named Alpha Cygni, because it is Cygnus' brightest star. And although it is only the 19th brightest star as seen from Earth, Deneb may in fact intrinsically be the brightest star that we can see. The absolute brightness of Deneb is an unanswered question in part because Deneb's distance is very uncertain. Deneb's distance from the Sun has been estimated to be anywhere from 1,600 light years to 7,400 light years away (equal to 44,400,000,000,000,000, or forty four quadrillion four hundred trillion miles!). 3,200 light years is the most commonly accepted figure. Even at its estimated closest, Deneb is still a vast distance from Earth, and yet it is still a First Magnitude star. And that is twice as true at twice that vast distance. Double that and more, and Deneb is brighter still.
Just for comparison, of the five brightest stars in our sky, Sirius, Canopus, Alpha Centauri, Arcturus and Vega, only Canopus lies more than 40 light years away (74). Alpha Centauri is just 4.3 light years away, and Sirius just eight.
Deneb is 20 times the mass and 220 times the radius of the Sun. Were it placed in the center of our Solar System, Deneb's surface would touch the Earth. It burns at 15,000 degrees F. Deneb's solar wind (the force with which it burns off mass) is 100,000 times that of our Sun. Deneb loses the mass of the Earth once every 500 years.
Deneb is just ten million years old, but with its prodigious energy output, Deneb may be leaving its Main Sequence. There is a possibility that, given its mass and size, Deneb may blow off enough stellar material to stabilize as a smaller, dimmer star, but there is an equal chance that Deneb could supernova. Astronomers are fascinated by either possibility, given Deneb's extraordinary properties. Deneb, of course, could have exploded on the day the Roman Empire fell and we wouldn't know about it for thousands of years yet. Remember that because light only travels at a set speed (even if it is the fastest thing we know) when we look at Deneb, because we are unsure of its distance, we may be looking back in time anywhere from the time of the Huns to the building of Solomon's Temple back to the first crossing of the Bering Strait by Asians. To study the stars is to time-travel.
Deneb is popular in science fiction, a favored location in Isaac Asimov's stories, the television show Babylon 5, and especially in Star Trek.
In "The Trouble With Tribbles", a Klingon compares Captain Kirk to a "Denebian Slime Devil," a greenish, multieyed creature of unpleasant provenance. In "I, Mudd", the space freebooter Harry Mudd has the following conversation with Mr. Spock:
Mudd : Do you know what the penalty for fraud is on Deneb 5?
Spock : Guilty party has his choice. Death by electrocution, death by gas, death by phaser, death by hanging, death by . . .
Mudd : The key word in your entire peroration, Mr. Spock, was . . . d-d-d-DEATH.
Scientists doubt that there really are any Denebians, but if they do exist, I want the Coppertone and Ray-Ban concession!
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