Delta Cancri
Encyclopedia
Delta Cancri is an orange giant star
approximately 180 light-year
s away in the constellation
Cancer
. It has the traditional name Asellus Australis which in Latin means "southern donkey
colt". It also has the longest of all known star names, Arkushanangarushashutu, derived from ancient Babylonian which means "the southeast star in the Crab".
In Chinese
, , meaning Ghost
(asterism), refers to an asterism consisting of δ Cancri, θ Cancri
, η Cancri
and γ Cancri
. Consequently, δ Cancri itself is known as
Since it is near the ecliptic
, it can be occulted
by the Moon
and very rarely by planet
s.
Delta Cancri also marks the famous open star cluster Praesepe (or the Beehive Cluster
, also known as Messier 44). In ancient times M44 was used as a weather gauge as the following Greek rhyme from Aratos' Prognostica reveals:
The meaning of this verse is that if Asellus Borealis or Gamma Cancris is hidden by clouds, the wind will be from the south and that situation will be reversed if Arkushanangarushashutu is obscured. There is some doubt however as to the accuracy of this as Allen notes: "Our modern Weather Bureau would probably tell us that if one of these stars were thus concealed, the other also would be." (Allen, 1898)
Delta Cancri also marks the radiant of the Delta Cancrids
meteor shower.
In 1876, the possibility of Delta Cancri having a companion
star was proposed.
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
approximately 180 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s away in the constellation
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....
Cancer
Cancer (constellation)
Cancer is one of the twelve constellations of the zodiac. Its name is Latin for crab and it is commonly represented as such. Its symbol is . Cancer is small and its stars are faint...
. It has the traditional name Asellus Australis which in Latin means "southern donkey
Donkey
The donkey or ass, Equus africanus asinus, is a domesticated member of the Equidae or horse family. The wild ancestor of the donkey is the African Wild Ass, E...
colt". It also has the longest of all known star names, Arkushanangarushashutu, derived from ancient Babylonian which means "the southeast star in the Crab".
In Chinese
Chinese language
The Chinese language is a language or language family consisting of varieties which are mutually intelligible to varying degrees. Originally the indigenous languages spoken by the Han Chinese in China, it forms one of the branches of Sino-Tibetan family of languages...
, , meaning Ghost
Ghost (Chinese constellation)
The Ghost mansion is one of the Twenty-eight mansions of the Chinese constellations. It is one of the southern mansions of the Vermilion Bird.-Asterisms:...
(asterism), refers to an asterism consisting of δ Cancri, θ Cancri
Theta Cancri
Theta Cancri is a binary star in the constellation Cancer, 494 light years from Earth.θ Cancri is classified as an orange K-type giant with an apparent magnitude of +5.33. Since it is near the ecliptic, it can be occulted by the Moon and, very rarely, by planets...
, η Cancri
Eta Cancri
Eta Cancri is a star in the constellation Cancer.η Cancri is an orange K-type giant with an apparent magnitude of +5.33. It is approximately 312 light years from Earth....
and γ Cancri
Gamma Cancri
Gamma Cancri is a star system in the constellation Cancer. It has the traditional name Asellus Borealis ....
. Consequently, δ Cancri itself is known as
Since it is near the ecliptic
Ecliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...
, it can be occulted
Occultation
An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer. The word is used in astronomy . It can also refer to any situation wherein an object in the foreground blocks from view an object in the background...
by the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
and very rarely by planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s.
History
Delta Cancri was involved in the first recorded occultation by Jupiter:Delta Cancri also marks the famous open star cluster Praesepe (or the Beehive Cluster
Beehive Cluster
The Beehive Cluster, also known as Praesepe , M44, NGC 2632, or Cr 189, is an open cluster in the constellation Cancer. It is one of the nearest open clusters to the Solar System, and it contains a larger star population than most other nearby clusters...
, also known as Messier 44). In ancient times M44 was used as a weather gauge as the following Greek rhyme from Aratos' Prognostica reveals:
The meaning of this verse is that if Asellus Borealis or Gamma Cancris is hidden by clouds, the wind will be from the south and that situation will be reversed if Arkushanangarushashutu is obscured. There is some doubt however as to the accuracy of this as Allen notes: "Our modern Weather Bureau would probably tell us that if one of these stars were thus concealed, the other also would be." (Allen, 1898)
Other
But Delta Cancri also acts as more than just a dubious weather guide: it is a reliable signpost for finding the vividly red star X Cancri as Patrick Moore notes in his guidebook Stars of the Southern Skies:Delta Cancri also marks the radiant of the Delta Cancrids
Delta Cancrids
The Delta Cancrids is a medium strength meteor shower lasting from December 14 to February 14, the main shower from January 1 to January 24. The radiant is located in the constellation of Cancer, near Delta Cancri. It peaks on January 17 each year, with only four meteors per hour. It was first...
meteor shower.
In 1876, the possibility of Delta Cancri having a companion
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...
star was proposed.
See also
- Gamma CancriGamma CancriGamma Cancri is a star system in the constellation Cancer. It has the traditional name Asellus Borealis ....
(Asellus Borealis) - Beehive ClusterBeehive ClusterThe Beehive Cluster, also known as Praesepe , M44, NGC 2632, or Cr 189, is an open cluster in the constellation Cancer. It is one of the nearest open clusters to the Solar System, and it contains a larger star population than most other nearby clusters...
(Messier 44, Praesepe) - 55 Cancri55 Cancri55 Cancri , also cataloged Rho1 Cancri or abbreviated 55 Cnc, is a binary star approximately 41 light-years away from Earth in the constellation of Cancer...
- AldebaranAldebaranAldebaran is a red giant star located about 65 light years away in the zodiac constellation of Taurus. With an average apparent magnitude of 0.87 it is the brightest star in the constellation and is one of the brightest stars in the nighttime sky...
- Pollux (star)Pollux (star)Pollux is an orange giant star approximately 34 light-years from the Earth in the constellation of Gemini . Pollux is the brightest star in the constellation, brighter than Castor...
- Delta CancridsDelta CancridsThe Delta Cancrids is a medium strength meteor shower lasting from December 14 to February 14, the main shower from January 1 to January 24. The radiant is located in the constellation of Cancer, near Delta Cancri. It peaks on January 17 each year, with only four meteors per hour. It was first...
(meteor shower)
books
- Allen, Richard Hinckley, Star Names: Their Lore and MeaningStar Names: Their Lore and MeaningStar Names: Their Lore and Meaning is a book by Richard Hinckley Allen, published in 1899.It discusses the names of stars and constellations and their origin.-Author:...
, Dover, 1898. - Burnham, Robert Jnr., Burnham's Celestial Handbook, Dover publications, 1978.
- Beresford Tony, Personal Communication (Letter on d Cancris.) 1997.
- Guinness, The Guinness Book of Records, Guinness Publishing, 1991.
- Kaler, James, B, ‘The Cambridge Encyclopaedia of Stars’, Cambridge University Press, 2006.
- Motz, Lloyd & Nathanson, Carol, Constellations, Aurum Press, 1991.
- Moore, Patrick, Atlas of the Universe, Phillips, 1994.
- Moore, Patrick, Stars of the Southern Skies, Penguin books, 1994.
