Hyades (star cluster)
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| Observation data: J2000.0 epoch | |
|---|---|
| Class: | II,3,m |
| Constellation: | |
| Right ascension: | 04h 27m |
| Declination: | +15° 52′ |
| Distance: | 151 ly (46 Pc) |
| Apparent magnitude (V): | 0.5 |
| Apparent dimensions (V): | 330′ |
| Physical characteristics | |
| Mass: | ( M☉) |
| Radius: | 30 light years |
| VHB: | |
| Estimated age: | 625 million years |
| Notable features: | constellation = Taurus |
| Other designations: | Mel 25, Col 50, Cal 41 |
| See also: Open cluster, List of open clusters | |
The Hyades (ÆΥάδες also known as Melotte 25 or Collinder 50 or Caldwell 41) is an open star cluster located in the constellation Taurus. Its brightest stars form a "V" shape along with the red giant Aldebaran, the brightest star in the field of view, which is not part of the cluster. The Hyades, at 151 light years from Earth, form the nearest star cluster (disregarding the Ursa Major Stream).
The distance to the Hyades is known accurately because each star's radial velocity and proper motion are the same and well measured, making it easy to compute the precise distance. The Hipparcos satellite confirmed this distance to be 151 light years.
While the cluster is about 75 light years in diameter, the prominent central group is about 10 light years in diameter. Its Hertzsprung-Russel diagram shows it to be 625±50 million years old [1]. It was probably formed from the same cloud as Praesepe.[2]
[edit] History
Being a naked-eye cluster, the Hyades were known prehistorically. It was mentioned by Homer in 750 BC. The cluster was probably first cataloged by Giovanni Batista Hodierna in 1654. Lewis Boss, in 1908, first showed that the arrangement of stars was a cluster. Charles Messier used star charts that included and labeled the Hyades, but did not place the cluster in his famous catalog.[2]
The Hyades, in Greek mythology, were the five daughters of Atlas and half-sisters to the Pleiades. The word actually comes from Greek Huades, probably from Hys meaning pig.[3]
[edit] References
- ^ Perryman, M.A.C., et al. (1998). "The Hyades: distance, structure, dynamics, and age". Astronomy & Astrophysics 331: 81-120.
- ^ a b Information on the Hyades from SEDS
- ^ American Heritage Dictionary
[edit] External links
- Information on the Hyades from SEDS
- Astronomy Picture of the Day
- WEBDA open cluster database website for Hyades cluster - E. Paunzen (Univ. Vienna)
