Seven Sisters of the space- Part 1

 Pleiades- Part 1

The Pleiades also known as The Seven Sisters and Messier 45, is an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. It is among the star clusters nearest to Earth, it is the nearest Messier object to Earth, and is the cluster most obvious to the naked eye in the night sky.

The cluster is dominated by hot blue and luminous stars that have formed within the last 100 million years. Reflection nebulae around the brightest stars were once thought to be left over material from their formation, but are now considered likely to be an unrelated dust cloud in the interstellar medium through which the stars are currently passing.

Computer simulations have shown that the Pleiades were probably formed from a compact configuration that resembled the Orion Nebula. Astronomers estimate that the cluster will survive for about another 250 million years, after which it will disperse due to gravitational interactions with its galactic neighborhood.

Together with the open star cluster of the Hyades, the Pleiades form the Golden Gate of the Ecliptic.

Origin of Name

The name of the Pleiades comes from Ancient Greek,  it probably derives from plein ("to sail") because of the cluster's importance in delimiting the sailing season in the Mediterranean Sea: "the season of navigation began with their heliacal rising". However, in mythology the name was used for the Pleiades, seven divine sisters, the name supposedly deriving from that of their mother Pleione and effectively meaning "daughters of Pleione". In reality, the name of the star cluster almost certainly came first, and Pleione was invented to explain it.

Folklore and Mythology

1 dollar commemorative coin issued in 2020 by the Royal Australian Mint. On the reverse, the Seven Sisters (Pleiades) are represented, according to an ancient story of Australian Indigenous tradition.

The Nebra sky disk, dated circa 1600 BC. The cluster of dots in the upper right portion of the disk is believed to be the Pleiades.

The Pleiades are a prominent sight in winter in the Northern Hemisphere, and are easily visible out to mid-Southern latitudes. They have been known since antiquity to cultures all around the world, including the Celts ( who call them Tŵr Tewdws[Tur Toodus]), Hawaiians (who call them Makaliʻi), Māori (who call them Matariki), Aboriginal Australians (from several traditions), the Persians, whence in Hindi and Urdu (who called them پروین Parvīn or پروی Parvī), the Arabs (who called them الثريا al-Thurayya[19]), the Chinese (who called them 昴 mǎo), the Quechua, the Japanese (who call them 昴 / スバル Subaru), the Maya, the Aztec, the Sioux, the Kiowa, and the Cherokee. In Hinduism, the Pleiades are known as Krittika and are associated with the war-god Kartikeya. They are also mentioned three times in the Bible.

The earliest-known depiction of the Pleiades is likely a Northern German Bronze Age artifact known as the Nebra sky disk, dated to approximately 1600 BC. The Babylonian star catalogues name the Pleiades MULMUL , meaning "stars" (literally "star star"), and they head the list of stars along the ecliptic, reflecting the fact that they were close to the point of vernal equinox around the 23rd century BC. The Ancient Egyptians may have used the names "Followers" and "Ennead" in the prognosis texts of the Calendar of Lucky and Unlucky Days of papyrus Cairo 86637. Some Greek astronomers considered them to be a distinct constellation, and they are mentioned by Hesiod's Works and Days, Homer's Iliad and Odyssey, and the Geoponica. Some scholars of Islam suggested that the Pleiades (ath-thurayya) are the "star" mentioned in Sura An-Najm ("The Star") of the Quran.

Subaru

In Japan, the cluster is mentioned under the name Mutsuraboshi ("six stars") in the 8th-century Kojiki.The cluster is now known in Japan as Subaru.

It was chosen as the name of the Subaru Telescope which is the 8.2-meter (320 in) flagship telescope of the National Astronomical Observatory of Japan. It is located at the Mauna Kea Observatory on the island of Hawaii. It had the largest monolithic primary mirror in the world from its commissioning in 1998 until 2005.]

It was chosen as the brand name of Subaru automobiles to reflect the origins of the firm as the joining of five companies, and is depicted in the firm's six-star logo.

Observational history

Galileo's drawings of the Pleiades star cluster from Sidereus Nuncius

Galileo Galilei was the first astronomer to view the Pleiades through a telescope. He thereby discovered that the cluster contains many stars too dim to be seen with the naked eye. He published his observations, including a sketch of the Pleiades showing 36 stars, in his treatise Sidereus Nuncius in March 1610.

The Pleiades have long been known to be a physically related group of stars rather than any chance alignment. John Michell calculated in 1767 that the probability of a chance alignment of so many bright stars was only 1 in 500,000, and so surmised that the Pleiades and many other clusters of stars must be physically related. When studies were first made of the stars' proper motions, it was found that they are all moving in the same direction across the sky, at the same rate, further demonstrating that they were related.

Charles Messier measured the position of the cluster and included it as M45 in his catalogue of comet-like objects, published in 1771. Along with the Orion Nebula and the Praesepe cluster, Messier's inclusion of the Pleiades has been noted as curious, as most of Messier's objects were much fainter and more easily confused with comets—something that seems scarcely possible for the Pleiades. One possibility is that Messier simply wanted to have a larger catalogue than his scientific rival Lacaille, whose 1755 catalogue contained 42 objects, and so he added some bright, well-known objects to boost his list.

Edme-Sébastien Jeaurat then drew in 1782 a map of 64 stars of the Pleiades from his observations in 1779, which he published in 1786.

      

To Be Continued.......

Link for Part 2-https://antrikshknowledge12345.blogspot.com/2021/08/seven-sisters-of-space-part-2.html 

-Kritik Raj