Albireo
Encyclopedia
Albireo is the fifth brightest star in the constellation
Cygnus
. Although it has the Bayer designation
beta, it is fainter than Gamma Cygni
, Delta Cygni
, and Epsilon Cygni
. Albireo appears to the naked eye to be a single star of magnitude 3 but through a telescope, even low magnification views resolve it into a double star
. The brighter yellow star (actually itself a very close binary system
) makes a striking colour contrast with its fainter blue companion star.
Albireo is 380 ly away from the Earth. When viewed with the naked eye, it appears to be a single star. However, in a telescope
it readily resolves into a double star
, consisting of Albireo A (amber, apparent magnitude
3.1), and Albireo B (blue-green, apparent magnitude 5.1.) Separated by 35 seconds of arc, the two components provide one of the best contrasting double stars in the sky due to their different colors. It is not known whether the two components are orbiting around each other in a physical binary system
. If they are, their orbital period is probably at least 100,000 years. Because of the respective colors of blue and yellow, the Albireo binary star system is unofficially known as the the University of California at Berkeley's "Cal Star."
, using speckle interferometry and the 2.1-meter telescope at the Kitt Peak National Observatory
. An orbit for the pair has since been computed using interferometric measurements, but as only approximately a quarter of the orbit has been observed, the orbital parameters must be regarded as preliminary. The current angular separation between the components of around 0.4 arcseconds, too close to be visually resolved except with instruments of at least 20" in size in exceptionally stable atmospheric conditions.
, with an equatorial rotational velocity of at least 250 kilometers per second. Its surface temperature has been spectroscopically
estimated to be about 13,200 K
.
, Gamma Cygni
, Delta Cygni
, and Epsilon Cygni
, it forms the asterism
called the Northern Cross
.
Medieval Arabic
-speaking astronomers called Albireo (English: the hen's beak). Its current name is a result of misunderstanding and mistranslation. It is thought that it originated in the Greek
name for the constellation of Cygnus, which became in Arabic. When translated into Latin, this name was thought to refer to the plant Erysimum officinale, and so was translated into a Latin name for this plant, . The phrase was later treated as a misprint of an Arabic term and transcribed as .
The term (منقار ألدجاجة) or Menchir al Dedjadjet appeared in the catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, which was translated into Latin
as Rostrum Gallinǣ, meaning the hen's beak.
was a United States Navy
Crater class cargo ship
named after the star.
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Cygnus
Cygnus (constellation)
Cygnus is a northern constellation lying on the plane of the Milky Way. Its name is the Latinized Hellenic word for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross...
. Although it has the Bayer designation
Bayer designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name...
beta, it is fainter than Gamma Cygni
Gamma Cygni
Gamma Cygni is a star in the constellation Cygnus. It has the traditional name Sadr ....
, Delta Cygni
Delta Cygni
Delta Cygni is the third-magnitude star in the constellation Cygnus. It has the traditional name Rukh. It will be the "North Star" for at least four centuries around 11,250....
, and Epsilon Cygni
Epsilon Cygni
Epsilon Cygni is a star in the constellation Cygnus . It is also called Gienah, a traditional name it shares with Gamma Corvi...
. Albireo appears to the naked eye to be a single star of magnitude 3 but through a telescope, even low magnification views resolve it into a double star
Double star
In observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope. This can happen either because the pair forms a binary star, i.e...
. The brighter yellow star (actually itself a very close binary system
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
) makes a striking colour contrast with its fainter blue companion star.
Double star
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
it readily resolves into a double star
Double star
In observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope. This can happen either because the pair forms a binary star, i.e...
, consisting of Albireo A (amber, apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
3.1), and Albireo B (blue-green, apparent magnitude 5.1.) Separated by 35 seconds of arc, the two components provide one of the best contrasting double stars in the sky due to their different colors. It is not known whether the two components are orbiting around each other in a physical binary system
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
. If they are, their orbital period is probably at least 100,000 years. Because of the respective colors of blue and yellow, the Albireo binary star system is unofficially known as the the University of California at Berkeley's "Cal Star."
Albireo A
In 1976, component A was itself discovered to be a binary starBinary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
, using speckle interferometry and the 2.1-meter telescope at the Kitt Peak National Observatory
Kitt Peak National Observatory
The Kitt Peak National Observatory is a United States astronomical observatory located on 2,096 m Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, southwest of Tucson...
. An orbit for the pair has since been computed using interferometric measurements, but as only approximately a quarter of the orbit has been observed, the orbital parameters must be regarded as preliminary. The current angular separation between the components of around 0.4 arcseconds, too close to be visually resolved except with instruments of at least 20" in size in exceptionally stable atmospheric conditions.
Albireo B
Albireo B is a fast-rotating Be starBe star
A Be star is a B-type star with prominent emission lines of hydrogen in its spectrum. The designation is combined by the spectral class, B, and the lowercase e denoting emission in the spectral classification system. Line emission from other atomic ions might be present as well, but is typically...
, with an equatorial rotational velocity of at least 250 kilometers per second. Its surface temperature has been spectroscopically
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
estimated to be about 13,200 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
.
Names and etymology
Since Cygnus is the swan, and Albireo is located at the head of the swan, Albireo is sometimes called the "beak star". With DenebDeneb
Deneb is the brightest star in the constellation Cygnus and one of the vertices of the Summer Triangle. It is the 19th brightest star in the night sky, with an apparent magnitude of 1.25. A blue-white supergiant, Deneb is also one of the most luminous nearby stars...
, Gamma Cygni
Gamma Cygni
Gamma Cygni is a star in the constellation Cygnus. It has the traditional name Sadr ....
, Delta Cygni
Delta Cygni
Delta Cygni is the third-magnitude star in the constellation Cygnus. It has the traditional name Rukh. It will be the "North Star" for at least four centuries around 11,250....
, and Epsilon Cygni
Epsilon Cygni
Epsilon Cygni is a star in the constellation Cygnus . It is also called Gienah, a traditional name it shares with Gamma Corvi...
, it forms the asterism
Asterism (astronomy)
In astronomy, an asterism is a pattern of stars recognized on Earth's night sky. It may form part of an official constellation, or be composed of stars from more than one. Like constellations, asterisms are in most cases composed of stars which, while they are visible in the same general direction,...
called the Northern Cross
Asterism (astronomy)
In astronomy, an asterism is a pattern of stars recognized on Earth's night sky. It may form part of an official constellation, or be composed of stars from more than one. Like constellations, asterisms are in most cases composed of stars which, while they are visible in the same general direction,...
.
Medieval Arabic
Arabic language
Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book...
-speaking astronomers called Albireo (English: the hen's beak). Its current name is a result of misunderstanding and mistranslation. It is thought that it originated in the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
name for the constellation of Cygnus, which became in Arabic. When translated into Latin, this name was thought to refer to the plant Erysimum officinale, and so was translated into a Latin name for this plant, . The phrase was later treated as a misprint of an Arabic term and transcribed as .
The term (منقار ألدجاجة) or Menchir al Dedjadjet appeared in the catalogue of stars in the Calendarium of Al Achsasi Al Mouakket, which was translated into Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
as Rostrum Gallinǣ, meaning the hen's beak.
Namesakes
USS Albireo (AK-90)USS Albireo (AK-90)
The USS Albireo was a Crater-class cargo ship in the service of the United States Navy in World War II. It was the only ship of the Navy to have borne this name. It is named after Albireo, a star in the constellation of Cygnus....
was a United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
Crater class cargo ship
Crater class cargo ship
Crater-class cargo ship is a category of freighter that was constructed for use by the United States Navy during World War II under Maritime Commission EC2-S-C1 type....
named after the star.
External links
- Albireo as a Triple Star
- Photo by Richard Yandrick; August 30, 2005
- A picture of Albireo by Stefan Seip
- NightSkyInfo.com - Albireo
- Albireo at Alcyone Software's Star Data Pages