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The Pleiades, also called Open cluster M45, visible from both the northern and southern hemispheres, consists of many bright, hot stars that were all formed at the same time within a large cloud of interstellar dust and gas. The blue haze that accompanies them is due to very fine dust which still remains and preferentially reflects the blue light from the stars. The picture shows the cluster with south at the top, as seen in an astronomical telescope.
The Pleiades (also known as M45, or the Seven Sisters) is an open cluster in the constellation of Taurus. It is among the nearest to earth of all open clusters, probably the best known and certainly the most striking to the naked eye.
The Pleiades are about 450 Light years away from earth and were formed approximately 100 million years ago. There are approximately 500 stars in total in the cluster, but it is dominated by young hot blue stars, up to 14 of which can be seen with the naked eye, depending on local observing conditions. The arrangement of the brightest stars is somewhat similar to the Plough and Ursa Minor (the Little Dipper).
Under ideal observing conditions, some hint of nebulosity may be seen around the cluster, and this shows up in long exposure photographs. It is a reflection nebula, caused by dust left over from star formation reflecting the blue light of the hot young stars.
Like most open clusters, the Pleiades will not stay gravitationally bound forever, as the component stars are moving faster than the escape velocity of the cluster. Calculations suggest that the cluster will take about 250 million years to disperse.
The 9 brightest stars of the Pleiades are named for the Seven Sisters of Greek mythology ( Asterope, MeropeIn Greek mythology, several unrelated women went by the name Merope bee-mask later reinterpreted as honey-like or eloquent), which may, therefore, have denoted a position in the cult of the Great Mother rather than a mere individual's name. Merope, one of, ElectraThis article is about the Greek mythological personalities, for other meanings see Electra (disambiguation). In Greek mythology, several persons were named Electra (also spelled Elektra : # Daughter of Oceanus and Tethys, mother of Dardanus, Iasion and Ha, MaiaMaia can mean several things: Maia in Greek mythology, is the eldest of the Pleiades, the seven daughters of Atlas and Pleione. Maia was identified in Roman mythology with Maia Maiestas (also called Fauna, Bona Dea (the 'Good Goddess') and Ops), a goddess, TaygeteIn Greek mythology, Taygete ( Greek: , in Modern Greek Taygeti Taigeti was a nymph, one of the Pleiades according to Apollodorus (3. 1) and a companion of Artemis, in her archaic role as potnia theron "Mistress of the animals. Mount Taygetos in Laconia, d, CelaenoIn Greek mythology, Celaeno referred to several different beings. One of the harpies, Celaeno ("the dark") was also known as Podarge ("fleet-foot"). The harpies were vicious winged monsters that terrorized Phineas among others. See Phineas for more detail and AlcyoneAlcyone was a Greek demi-goddess, sometimes regarded as one of the Pleiades. More often she was thought of as the daughter of Aeolus and wife of Ceyx, son of Eosphorus and the king of Thessaly. They were very happy together, but, when Ceyx perished in a s) and their parents AtlasIn Greek mythology, Atlas ("he who dares or suffers") was the son of the Titan Iapetus and the nymph Clymene, and brother of Prometheus. He was the father of the Hesperides, Maera, the Hyades, Calypso and the Pleiades. Because Atlas fought on the side of and PleionePleione is in Greek mythology, an Oceanid, daughter of Oceanus and Tethys. With Atlas, she gave birth to the seven Pleiades. a genus of mainly ground orchids see Pleione .. The Hyades were sisters of the Pleiades. The following table gives details of these stars:
| Name | Designation | m | Type | Catalog |
|---|---|---|---|---|
| Alcyone | eta (25) Tauri | 2.86 | B7e III | vdB 23 |
| Atlas | 27 Tauri | 3.62 | B8 III | Ced 190 |
| Electra | 17 Tauri | 3.70 | B6e III | vdB 20 |
| Maia | 20 Tauri | 3.86 | B7 III | NGC 1432 |
| Merope | 23 Tauri | 4.17 | B6 IV | NGC 1435, IC 349 |
| Taygeta | 19 Tauri | 4.29 | B6 V | Ced 19e |
| Pleione | BU (28) Tauri | 5.09 (var.) | B8e p | Ced 19p |
| Celaeno | 16 Tauri | 5.44 | B7 IV | Ced 19c |
| Asterope | 21 and 22 Tauri | 5.64/6.41 | B8e V/B9 V |
The name of the cluster itself has uncertain etymology, with suggested origins being from plein, to sail, making the Pleiades the 'sailing ones'; from pleos, full or many; or from pelaiades, flock of doves (in the Greek legend, the sisters are transformed into birds).