Pleiades

Pleiades
Pleiades
	A color-composite image of the Pleiades from the Digitized Sky Survey
Observation data (J2000 epoch)
Right ascension	03h 47m 24s
Declination	+24° 07′ 00″
Distance	444 ly on average (136.2±1.2 pc)
Apparent magnitude (V)	1.6
Apparent dimensions (V)	2°
Physical characteristics
Mass	800 M☉
Radius	20.34 light-years
Estimated age	75 to 150 million years
Other designations	Seven Sisters, M45, Cr 42, Mel 22
Associations
Constellation	Taurus
	See also: Open cluster, List of open clusters

The Pleiades (/ˈpliː.ədiːz, ˈpleɪ-, ˈplaɪ-/),^[8]^[9] also known as the Seven Sisters, Messier 45, and other names by different cultures, is an asterism and an open star cluster containing middle-aged, hot B-type stars in the north-west of the constellation Taurus. At a distance of about 444 light-years, it is among the nearest star clusters to Earth. It is the nearest Messier object to Earth, and is the most obvious cluster to the naked eye in the night sky. It is also observed to house the reflection nebula NGC 1432, an HII region.^[10]

The cluster is dominated by hot blue luminous stars that have formed within the last 100 million years. Reflection nebulae around the brightest stars were once thought to be leftover 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.^[11] This dust cloud is estimated to be moving at a speed of approximately 18 km/s relative to the stars in the cluster.^[12]

Computer simulations have shown that the Pleiades were probably formed from a compact configuration that resembled the Orion Nebula.^[13] 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.^[14]

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

^ ^a ^b ^c ^d ^e ^f "Cl Melotte 22". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-04-20.
^ Cite error: The named reference vanleeuwen09 was invoked but never defined (see the help page).
^ Cite error: The named reference majaess11 was invoked but never defined (see the help page).
^ Cite error: The named reference Percival was invoked but never defined (see the help page).
^ Cite error: The named reference Zwahlen was invoked but never defined (see the help page).
^ ^a ^b Messier 45
^ Danilov, V. M.; Seleznev, A. F. (2020-10-01). "On the Motion of Stars in the Pleiades According to Gaia DR2 Data". Astrophysical Bulletin. 75: 407–424. doi:10.1134/S1990341320040045.
^ "Pleiades". Merriam-Webster.com Dictionary.
^ "Pleiades". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
^ "NGC 1432 (Maia Nebula) | TheSkyLive.com". theskylive.com. Retrieved 2022-12-10.
^ Gibson, S.J.; Nordsieck, K.H. (2003). "The Pleiades Reflection Nebula. II. Simple Model Constraints on Dust Properties and Scattering Geometry". The Astrophysical Journal. 589 (1): 362–377. Bibcode:2003ApJ...589..362G. doi:10.1086/374590.
^ White, Richard E.; Bally, John (May 1993). "Interstellar matter near the Pleiades. IV - The wake of the Pleiades through the interstellar medium in Taurus". The Astrophysical Journal. 409: 234. Bibcode:1993ApJ...409..234W. doi:10.1086/172658. eISSN 1538-4357. ISSN 0004-637X.
^ Kroupa, Pavel; Aarseth, Sverre; Hurley, Jarrod (2001). "The formation of a bound star cluster: From the Orion nebula cluster to the Pleiades". Monthly Notices of the Royal Astronomical Society. 321 (4): 699–712. arXiv:astro-ph/0009470. Bibcode:2001MNRAS.321..699K. doi:10.1046/j.1365-8711.2001.04050.x. S2CID 11660522.
^ Gendler, Robert (2006). A Year in the Life of the Universe: A Seasonal Guide to Viewing the Cosmos. Voyageur Press. p. 54. ISBN 978-1610603409.

[simbad-1] ^ ^a ^b ^c ^d ^e ^f "Cl Melotte 22". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-04-20.

[vanleeuwen09-2] Cite error: The named reference vanleeuwen09 was invoked but never defined (see the help page).

[majaess11-3] Cite error: The named reference majaess11 was invoked but never defined (see the help page).

[Percival-4] Cite error: The named reference Percival was invoked but never defined (see the help page).

[Zwahlen-5] Cite error: The named reference Zwahlen was invoked but never defined (see the help page).

[SEDS-6] Messier 45

[7] Danilov, V. M.; Seleznev, A. F. (2020-10-01). "On the Motion of Stars in the Pleiades According to Gaia DR2 Data". Astrophysical Bulletin. 75: 407–424. doi:10.1134/S1990341320040045.

[8] "Pleiades". Merriam-Webster.com Dictionary.

[9] "Pleiades". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)

[10] "NGC 1432 (Maia Nebula) | TheSkyLive.com". theskylive.com. Retrieved 2022-12-10.

[Gibson2003-11] Gibson, S.J.; Nordsieck, K.H. (2003). "The Pleiades Reflection Nebula. II. Simple Model Constraints on Dust Properties and Scattering Geometry". The Astrophysical Journal. 589 (1): 362–377. Bibcode:2003ApJ...589..362G. doi:10.1086/374590.

[12] White, Richard E.; Bally, John (May 1993). "Interstellar matter near the Pleiades. IV - The wake of the Pleiades through the interstellar medium in Taurus". The Astrophysical Journal. 409: 234. Bibcode:1993ApJ...409..234W. doi:10.1086/172658. eISSN 1538-4357. ISSN 0004-637X.

[Kroupa2001-13] Kroupa, Pavel; Aarseth, Sverre; Hurley, Jarrod (2001). "The formation of a bound star cluster: From the Orion nebula cluster to the Pleiades". Monthly Notices of the Royal Astronomical Society. 321 (4): 699–712. arXiv:astro-ph/0009470. Bibcode:2001MNRAS.321..699K. doi:10.1046/j.1365-8711.2001.04050.x. S2CID 11660522.

[Gendler2006-14] Gendler, Robert (2006). A Year in the Life of the Universe: A Seasonal Guide to Viewing the Cosmos. Voyageur Press. p. 54. ISBN 978-1610603409.

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