Altair

Altair.
Observation data Epoch J2000
Constellation	Aquila
Right ascension	19h 50m 47.0s
Declination	+08° 52' 06"
Apparent magnitude (V)	0.77
Spectral Characteristics
Spectral type	A7 IV-V
U-B color index	0.08
B-V color index	0.22
Variable type	None
Astrometry
Radial velocity (Rv)	−26.1 km/s
Proper motion (μ)	RA: 536.82 mas/yr Dec.: 385.54 mas/yr
Parallax (π)	194.97 ± 0.86 mas
Distance	16.73 ± 0.07 ly (5.13 ± 0.02 pc)
Absolute magnitude (MV)	2.22
Physical Characteristics
Mass	1.7 M☉
Radius	1.7 R☉
Luminosity	10.7 L☉
Temperature	8,000 K
Metallicity	200% Sun
Rotation	6.5–10.4 hours
Age	<109 years
Other designations
α Aquilae, 53 Aquilae, HD 187642, HR 7557, BD+08°4236, GCTP 4665.00, GJ 768, LHS 3490, and HIP 97649.

Altair (α Aql / α Aquilae / Alpha Aquilae / Atair ) is the brightest star in the constellation Aquila and the twelfth brightest star in the nighttime sky, at visual magnitude 0.77. Image File history File links PIA04204. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... This article or section does not cite its references or sources. ... Aquila (IPA: , Latin: ; sometimes named the Vulture), is one of the 48 constellations listed by Ptolemy, also mentioned by Eudoxus (4th cent. ... Equatorial Coordinates Right ascension (abbrev. ... In astronomy, declination (dec) is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... In astronomy, the color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. ... In astronomy, the color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. ... Most stars are of almost constant luminosity. ... This article does not cite its references or sources. ... Radial velocity is the velocity of an object in the direction of the line of sight. ... kilometre per second is an SI derived unit of both speed (scalar) and velocity (vector), signified by the symbol km/s or km s-1. ... The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... This does not cite its references or sources. ... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... Distance is a numerical description of how far apart things lie. ... A light-year or lightyear, symbol ly, is a unit of length. ... Stellar parallax motion The parsec (symbol pc) is a unit of length used in astronomy. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. ... Unsolved problems in physics: What causes anything to have mass? Mass is a property of a physical object that quantifies the amount of matter and energy it is equivalent to. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... Remote Authentication Dial In User Service (RADIUS) is an AAA (authentication, authorization and accounting) protocol for applications such as network access or IP mobility. ... In astronomy, the solar radius is a unit of length used to express the size of stars and larger objects such as galaxies. ... Luminosity has different meanings in several different fields of science. ... The solar luminosity, , is a unit of luminosity (power emitted in the form of photons) conventionally used by astronomers to give the luminosities of stars. ... Fig. ... The Kelvin scale is a thermodynamic (absolute) temperature scale where absolute zero—the lowest possible temperature where nothing could be colder and no heat energy remains in a substance—is defined as zero kelvin (0 K). ... In astronomy, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium. ... A sphere rotating around its axis. ... This article is about the astronomical object. ... A year is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... In astronomy, many stars are referred to simply by catalogue numbers. ... The Henry Draper Catalogue is an astronomy catalogue with astrometric and spectroscopic data about more than 225,000 stars. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... Alpha (uppercase Α, lowercase α) is the first letter of the Greek alphabet. ... This article is about the astronomical object. ... This article or section does not cite its references or sources. ... Aquila (IPA: , Latin: ; sometimes named the Vulture), is one of the 48 constellations listed by Ptolemy, also mentioned by Eudoxus (4th cent. ... Bright stars can be bright because they produce more light, because they are closer to us, or both. ... The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ...

Altair is a vertex of the Summer Triangle. It is an "A" type or white star located 17 light years away from Earth (about 99 trillion miles), one of the closest stars visible to the naked eye. In geometry, a vertex (Latin: whirl, whirlpool; plural vertices) is a corner of a polygon (where two sides meet) or of a polyhedron (where three or more faces and an equal number of edges meet). ... The Summer Triangle is an astronomical asterism involving an imaginary triangle drawn on the northern hemispheres celestial sphere, with its defining vertices at Altair, Deneb, and Vega. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... A light-year or lightyear, symbol ly, is a unit of length. ... The naked eye is a figure of speech referring to human visual perception that is unaided by enhancing equipment, such as a telescope or binoculars. ...

The name "Altair" is Arabic for "the Flying", from the phrase نسر الطائر an-nasr aţ-ţā?ir "the Flying Eagle". The spelling "Atair" is also used frequently. Arabic ( or just ), is the largest member of the family of Semitic branch of the Afro-Asiatic language family (classification: South Central Semitic) and is closely related to Hebrew, Amharic, and Aramaic. ...

It is officially known as 河鼓二 (Hégǔ'èr, the Second Star of the Drum at the River) in Chinese. However, it is more famous known as its other names: 牵牛星 or 牛郎星 (the Star of the Cowherd), after the Cowherd in the Chinese mythology: the Cowherd and the Weaver Girl. Qi Xi (七夕; Pinyin: qÄ« xÄ«; The Night of Sevens), sometimes called Chinese Valentines Day, falls on the seventh day of the seventh lunar month on the Chinese calendar; thus its name. ...

Altair is most notable for its extremely rapid rotation; by measuring the width of its spectral lines, it was determined that its equator does a complete rotation in about 6½ hours (various other sources give 9 hours, or 10.4 hours). In comparison, our star, the Sun, requires a little more than 25 days for a complete rotation. As a result of its rapid rotation, Altair is oblate: its equatorial diameter is at least 14 percent greater than its polar diameter. A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... World map showing the equator in red The Equator is an imaginary circle drawn around a planet (or other astronomical object) at a distance halfway between the poles. ... The Sun is the star at the centre of the Solar System[]. The Earth and other matter (including other planets, asteroids, meteoroids, comets and dust) orbit the Sun, which by itself accounts for more than 99% of the solar systems mass[]. Energy from the Sun—in the form of... An oblate spheroid is ellipsoid having a shorter axis and two equal longer axes. ...

Altair, along with Beta Aquilae and Gamma Aquilae, form the well-known line of stars sometimes referred to as the shaft of Aquila. The star Alshain (Scientific Name Beta Aquilae) is located at right ascension 19h 55. ... TARAZED (Gamma Aquilae). ...

References to the star

In Chinese mythology, there is a love story of Qi Xi in which Niu Lang (Altair) and his two children (Aquila -β and -γ) are separated forever from their mother Zhi Nü (Vega) who is on the far side of the river, the Milky Way. The Japanese Tanabata festival is also based on this legend. Chinese Mythology is a collection of cultural history, folktales, and religions that have been passed down in oral or written form. ... Qi Xi (七夕; Pinyin: qÄ« xÄ«; The Night of Sevens), sometimes called Chinese Valentines Day, falls on the seventh day of the seventh lunar month on the Chinese calendar; thus its name. ... Vega (α Lyr / α Lyrae / Alpha Lyrae) is a white main sequence star approximately 25. ... The Milky Way (a translation of the Latin Via Lactea, in turn derived from the Greek Γαλαξίας (Galaxias), sometimes referred to simply as the Galaxy), is a barred spiral galaxy of the Local Group. ... People dressed in yukata at Tanabata Tanabata ), meaning Seven Evenings) is a Japanese star festival, derived from Obon traditions and the Chinese star festival, Qi Xi. ...

In astrology, the star Altair was ill-omened, portending danger from reptiles. Hand-coloured version of the anonymous Flammarion woodcut. ... Subclasses Anapsida Diapsida Reptiles are tetrapods and amniotes, animals whose embryos are surrounded by an amniotic membrane. ...

In computing, an important early microcomputer, the Altair 8800, was named after the star because the daughter of the man responsible for coming up with a suitable name, when asked what she thought the computer should be called, was watching an episode of Star Trek where the Starship Enterprise had the star Altair as its destination. So Altair it was. Originally, the word computing was synonymous with counting and calculating, and a science and technology that deals with the original sense of computing mathematical calculations. ... Altair 8800 The MITS Altair 8800 was a microcomputer design from 1975, based on the Intel 8080A CPU. Sold as a kit through Popular Electronics magazine, the designers intended to sell only a few hundred to hobbyists, and were surprised when they sold over ten times that many in the...

In space travel, Altair is: Space exploration is the physical exploration of outer-Earth objects and generally anything that involves the technologies, science, and politics regarding space endeavors. ...

• The NASA Crew Exploration Vehicle (CEV) designed to travel to the Moon and International Space Station.

Altair is also the name of a Soviet-made analog synthesizer. [1] The National Aeronautics and Space Administration (NASA) is an agency of the United States Government, responsible for that nations public space program. ... CEV with lunar lander CEV during a landing on earth CEV rocket, the Crew Launch Vehicle (CLV) (right) along side the heavy-lift Cargo Launch Vehicle (CaLV) rocket. ...

See also

• Altair in fiction

Altair (Alpha Aquilae) is a bright white star in the constellation Aquila which is a frequent setting in science fiction: The planet Altair IV, the main setting of the book and film Forbidden Planet The homeworld of Harlan, an artificial lifeform in Stargate SG-1 In Star Trek, Altair IV...

Location

The star's location in the constellation of Aquila is shown in the following map:

This is a celestial map of the constellation Aquila the Eagle. ... This is a celestial map of the constellation Aquila the Eagle. ...

External links

• Report on ultra high-resolution photograph.
• SolStation