Hyades (star cluster)

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Observation data (J2000.0 epoch)
Hyades Cluster

Constellation	Taurus
Right ascension	04^h 27^m
Declination	+15° 52′
Distance	151 ly (46 Pc)
Apparent magnitude (V)	0.5
Apparent dimensions (V)	330′
Other designations	Mel 25, Col 50, Cal 41
See also: Open cluster, List of open clusters

The Hyades (Ὑάδες 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. After the death of their brother, Hyas, the weeping sisters were transformed into a cluster of stars which was afterwards associated with rain. Hyades is a star cluster that makes up Taurus, the bull, second sign in the annual horoscope.