Monday, August 20, 2007


Star type
g A7

Distance from Earth
g 16.72 ly

Star Service No.
g NA

g Few hundred million years old

Diameter/Mass/Temp (xSol)
g 170%; 180%; 8000 K

Brightness (xSol)
g 1070% (radiates higher than Sun in ultraviolet wavelengths)

g 200%

Comparison to Sol
g See illustration (Altair is slightly smaller than Sirius)

Picture of star
g See picture

Star system features
g Altair is 14 percent wider than it is tall (see video)
g Future: Will exhaust its core hydrogen around only a billion years and turn into a red giant or Cepheid variable before puffing away its outer layers to reveal a remnant core as a white dwarf

Known planets
g None, but dust has been detected around star; this dust disk may have developed after most of the surrounding nebulae of gas has been absorbed or expelled as a shell of gas from the developing star before it reached the main sequence

Habitable zone
g Distance where an Earth-type planet would be "comfortable" with liquid water is centered around 3.4 AUs, at the outer reaches of the Main Asteroid Belt's orbital distance in the Solar System. At that distance from the star, such a planet would have an orbital period of about 4.4 Earth years. If there is life on any Earth-type planet orbiting youthful Altair, it is likely to be primitive single-cell, anaerobic (non-oxygen producing) bacteria under constant bombardment by meteorites and comets as Earth was for the first billion years. Since there is unlikely to be free oxygen in the atmosphere of such a planet, it probably would not have an ozone layer (O3) although Altair puts out a lot more hard radiation (especially ultraviolet) than Sol.

Orbital map
g NA

View from star
g See sky map

Nearby stars
(Star systems with 10 light years)
g Ross 652 A/Van Biesbroeck's: 3.7 ly
g 70 Ophiuchi AB: 7.8 ly
g Hip 103039: 9.1 ly
g 61 Cygni AB: 9.8 ly
g V1581 Cygni AB: 9.8 ly
g AC+17 534-105: 10 ly

Map locating star system
g See stellar map

Location in Earth sky
g In the north central part of Constellation Aquila, the Eagle. It is also the lower left member of the "Summer Triangle" of first magnitude stars viewed from the northern hemisphere, formed with Vega (Alpha Lyrae) at the lower right, and Deneb (Alpha Cygni) at upper right. Altair is readily visible to the naked eye.

Other names
g Alpha Aquilae
g GJ 768
g HD 165341
g HIP 97649
g LHS 3490
g NSV 24910
g Alp or Alf Aql
g 53 Aql
g HR 7557
g BD+08 4236
g SAO 125122
g FK5 745
g LTT 15795
g LFT 1499
g ADS 13009 A

Sci-fi mentions
g In “The Hitchhikers Guide to the Galaxy,” the common currency is the Altairian Dollar.
g In the novel Sunstorm, a gas giant fifteen times the mass of Jupiter was launched by the Firstborn alien race from the Altair star system on a collision course with Earth's Sun in order to trigger a devastating solar flare that would completely sterilize the Earth.
g Altair is the home of Ahrian in Leigh Brackett's "The Woman from Altair".
g Altair VI is a planet in "The Winds of Altair" by Ben Bova, a novel about the colonization and terraforming of this planet, which is home to a race as intelligent as man.
g Angharad Gwyn is born and rescued from the planet Altair in "The Rowan" by Anne McCaffrey.
g In Stephen King's novel "The Tommyknockers", Altair IV is a desolate, nearly airless world where objects from all over the galaxy are stored. The name is most likely a reference to "Forbidden Planet" below.
g Edmund Cooper's "A Far Sunset" (Ace Books, 1967) has the starship Gloria Mundi meeting the Bayani race on Altair V in 2028
g Altair is the homeworld of Harlan, an artificial lifeform in "Stargate SG-1".
g The planet Altair IV is the main setting of the film "Forbidden Planet".
g Altair IV is the location of a prestigious hospital in the "Star Trek: Deep Space 9" episode "Prophet Motive", and a planet recovering from war with neighboring Altair VI in the "Star Trek: The Original Series" episode "Amok Time". Altair water is a commercially available beverage from the Altair system; in the movie "Star Trek III: The Search for Spock", McCoy drinks Altair water. The Altair sandwich is named after the star (DS9: "You Are Cordially Invited"), and "Setar of Altair" apparently is an important, well-known person (TOS: The Ultimate Computer").
g Altair V is the planet of origin for Rafael Argus in the '70s Buck Rogers episode "Plot to Kill A City"
g Altair III is mentioned in the play "Doctor Who - The Ultimate Adventure".
g In the Futurama episode "The Cyber House Rules", Adlai and Leela walk past an Altairean Bouquet Tree. Altair may simply be the name of the planetary system, and not the planet.
g In the game "Galactic Civilizations", there is a race known as the Altarians.
g Altair is the homeworld of the Ancients, an extinct civilization annihilated by the Shivans 8,000 years ago, in the space-combat simulation game, "FreeSpace 2".
g Altair is the homeworld of the Alkari, one of the alien races in the "Master of Orion" computer game series.
g The "Third Planet from Altair" (Choose Your Own Adventure #7, by Edward Packard, author, and Paul Granger, illustrator) describes in multiple scenarios an expedition to the planet of the namesake to investigate the source of transmitted signals received by Earth.
g In the "Frontier: Elite II" and "Frontier: First Encounters" games, Altair has a habitable world and a profitable tourism industry. It is also a Federation member.
g Altair Nine is an earth colony in Frederik Pohl's short story "The Day the Icicle Works Closed"

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