The Hyades (pronounced “high-uh-deez”), also known as the “Weeping Sisters,” or the “Rainy Ones,” is the name for an open cluster of stars located within the constellation Taurus, near their more famous sisters, the Pleiades.
What is the Hyades Star Cluster?
While the dazzling blue Pleiades get more attention, the Hyades are no slouches in the looks department. The cluster—which is the closest to our Solar System, at 151 light years away, and the most closely studied—contains hundreds of closely-related stars, 20 of which can be seen with the naked eye. Of those, the five brightest, Gamma Tauri, Delta 1 Tauri, Epsilon Tauri, Theta Tauri, and Zeta 1 Tauri, sit slightly apart from the rest of the group. The first four form a V shape that is known as the head of Taurus the Bull. Epsilon Tauri, also known as Ain, or the “Bull’s Eye,” is notable in that it has a planetary satellite, the first known planet in any open cluster.
An open star cluster is a group of stars all created by the explosion of one larger star. They are interesting because all component stars are the the same age, have the same chemical makeup, and move through space at the same speed. Open clusters differ from globular clusters, the other kind of star cluster, in their age and shape. Globular clusters are generally older and more tightly spaced, whereas open clusters are younger and more spread out. The Hyades are estimated to be about 625 million years old.
Aldebaran, The Eye of the Bull
From Earth, the bright red giant star Aldebaran looks to be a part of the cluster, but it is actually much closer to Earth than the Hyades, at 65 light years away. Its apparent proximity to the cluster is only an optical illusion.
Hyades of Greek Myth
The formation is named after the Hyades of Greek myth, water nymphs who were daughters of the titan Atlas. The sisters—most often numbered at five, though tellings vary from as few as three to as many as 15—got their lachrymose nickname due to their effusive grief after their brother, Hyas, was killed in a hunting accident.
Legend says the gods placed the sisters in the sky, where they would pour out their grief for all eternity. The ancient Greeks believed heavy rains would always accompany the Hyades’ first ascension above the horizon, as well as their eventual disappearance.
As a winter constellation, Taurus appears each fall and slips beneath the horizon each spring, bringing the Hyades with it. This is why, in England, the formation was once popularly known as the “April Rainers” to explain the “April showers” common for that time of year.
To locate: The Hyades can be located easily in the western sky in the spring, and in the south on winter evenings. An easy way to find them (binoculars help but are not necessary) is to locate Orion. An imaginary line drawn upward through the three stars of Orion’s Belt will lead you to the bright red star Aldebaran, the “fiery” eye of Taurus the Bull, and to the beautiful star clusters, the Hyades.