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Clusters of Young Stars in the North American Nebula Rolled Canvas Art Stocktrek Images 14 X 14

Written By الأربعاء، 27 أبريل 2022 Add Comment Edit

Emission nebula in the constellation Cygnus

North America Nebula
Emission nebula
H 2 region
North America and Pelican - Wesley Chang.jpg

Due north America and Pelican Nebulae
Observation data: J2000.0 epoch
Right ascension 20h 59m 17.anes [i]
Declination +44° 31′ 44″[i]
Altitude 2,590 ± 80 ly   (795 ± 25[2] pc)
Apparent magnitude (V) 4
Apparent dimensions (V) 120 × 100 arcmin[3]
Constellation Cygnus
Designations NGC 7000, Sharpless 117, Caldwell 20
See also: Lists of nebulae

The North America Nebula (NGC 7000 or Caldwell 20) is an emission nebula in the constellation Cygnus, shut to Deneb (the tail of the swan and its brightest star). The shape of the nebula resembles that of the continent of Due north America, consummate with a prominent Gulf of United mexican states.

History [edit]

On October 24, 1786, William Herschel observing from Slough, England, noted a "faint milky nebulosity scattered over this space, in some places pretty bright." [iv] The most prominent region was catalogued by his son John Herschel on August 21, 1829. It was listed in the New General Catalogue as NGC 7000, where it is described as a "faint, most extremely large, lengthened nebulosity." [five]

In 1890, the pioneering High german astrophotographer Max Wolf noticed this nebula's feature shape on a long-exposure photograph, and dubbed it the Northward America Nebula.[vi]

In his study of nebulae on the Palomar Sky Survey plates in 1959, American astronomer Stewart Sharpless realised that the North America Nebula is part of the same interstellar deject of ionized hydrogen (H II region) as the Pelican Nebula, separated past a dark band of grit, and listed the 2 nebulae together in his second listing of 313 brilliant nebulae as Sh2-117. American astronomer Beverly T. Lynds catalogued the obscuring grit cloud as L935 in her 1962 compilation of nighttime nebulae. Dutch radio astronomer Gart Westerhout detected the HII region Sh2-117 as a potent radio emitter, 3° across, and it appears as W80 in his 1958 catalogue of radio sources in the ring of the Milky way.[7]

General data [edit]

The North America Nebula covers a region more than ten times the area of the total moon, but its surface effulgence is low, so usually it cannot be seen with the unaided middle. Binoculars and telescopes with large fields of view (approximately three°) will show it every bit a foggy patch of light under sufficiently dark skies. Notwithstanding, using a UHC filter, which filters out some unwanted wavelengths of low-cal, it can be seen without magnification under nighttime skies. Its shape and reddish color (from the hydrogen Hα emission line) show up only in photographs of the area.[6]

The portion of the nebula resembling United mexican states and Central America is known every bit the Cygnus Wall. This region exhibits the most full-bodied star formation.[eight]

At optical wavelengths, the N America Nebula and the Pelican Nebula (IC 5070) announced singled-out as they are separated by the silhouette of the dark band of interstellar dust L935. The nighttime cloud is however transparent to radio waves and infrared radiation, and these wavelengths reveal the central regions of Sh2-117 that are not visible to an ordinary telescope, including many highly luminous stars.[ix]

Distance and size [edit]

The distances to the North America and Pelican nebulae were controversial, considering there are few precise methods for determining how far away an HII region lies. Until 2020, most astronomers accepted a value of 2,000 light years, though estimates ranged from 1,500 to three,000 light years.[ten]

But in 2020, the Gaia astrometry spacecraft measured the distances to 395 stars lying inside the HII region, giving the Due north America and Pelican nebulae a distance of ii,590 low-cal years (795±25 parsecs). The entire HII region Sh2-117 is estimated to be 140 lite years across, and the North America nebula stretches ninety light years n to s.[two]

Ionising star [edit]

HII regions shine because their hydrogen gas is ionised by the ultraviolet radiations from a hot star. In 1922, Edwin Hubble proposed that Deneb may be responsible for lighting upwards the Northward America Nebula, only it soon became apparent that it is not hot enough: Deneb has a surface temperature of 8,500 K, while the nebula's spectrum shows it is being heated by a star hotter than 30,000 K. In improver, Deneb is well away from the centre of the consummate North America/Pelican nebula complex (Sh2-117), and by 1958 George Herbig realised that the ionizing star had to lie backside the central dark cloud L935. In 2004, European astronomers Fernando Comerón and Anna Pasquali searched for the ionizing star behind L935 at infrared wavelengths, using data from the 2MASS survey, and so made detailed observations of likely suspects with the two.2 m telescope at the Calar Alto Observatory in Kingdom of spain. One star, catalogued J205551.3+435225, fulfilled all the criteria. Lying right in the heart of Sh2-117, with a temperature of over 40,000 1000, it is about certainly the ionising star for the N America and Pelican nebulae.[eleven]

Later observations have revealed J205551.3+435225 is a spectral type O3.5 star, with some other hot star (blazon O8) in orbit. J205551.3+435225 lies only off the "Florida coast" of the Northward America Nebula, so information technology has been more conveniently nicknamed the Bajamar Star ("Islas de Bajamar," significant "low-tide islands" in Spanish, was the original name of the Bahamas considering many of them are just easily seen from a ship during low tide).[12]

Although the light from the Bajamar Star is dimmed by 9.6 magnitudes (near 10,000 times) past the dark cloud L935, it is faintly visible at optical wavelengths, at magnitude thirteen.two. If we saw this star undimmed, information technology would shine at magnitude 3.6, near as bright every bit Albireo, the star marker the swan's caput.[11]

Gallery [edit]

  • North America and Pelican nebulae viewed in optical (top left) and successively longer infrared wavelengths, which penetrate the grit deject between them.

  • North America and Pelican nebulae with four" refractor

  • Due north America Nebula with Triad Quadband Filter

  • The Peachy Wall of the North America Nebula shot in colour with a dual narrowband filter.

Run into also [edit]

  • Pelican Nebula

References [edit]

  1. ^ a b "NASA/IPAC Extragalactic Database". Results for NGC 7000 . Retrieved 2006-10-17 .
  2. ^ a b Kuhn, Michael A.; Hillenbrand, Lynne A.; Carpenter, John M.; Menendez, Angel Rodrigo Avelar (2020). "The Formation of a Stellar Association in the NGC 7000/IC 5070 Complex: Results from Kinematic Analysis of Stars and Gas" (PDF). The Astrophysical Journal. 899 (ii): 128–167. doi:ten.3847/1538-4357/aba19a. Retrieved 2 September 2020.
  3. ^ Frommert, Hartmut; Kronberg, Christine (2020). "NGC 7000". SEDS . Retrieved 26 August 2020.
  4. ^ Latusseck, Arndt (2008). "William Herschel's 50-two fields of extensive diffused nebulosity – a revision". Retrieved 26 August 2020.
  5. ^ Seligman, Courtney (2020). "NGC 7000, The North America Nebula". Celestial Atlas . Retrieved 26 August 2020.
  6. ^ a b French, Sue (2004). "Navigating North America" (PDF). Sky & Telescope. Sky Publishing Corp. Retrieved 26 August 2020.
  7. ^ Jardine, Kevin. "Sh 2-117". Milky way Map . Retrieved 26 August 2020.
  8. ^ Wager, Sara (2016). "The Cygnus Wall of Star Formation". Astronomy Moving-picture show of the Day. NASA. Retrieved 2 September 2020.
  9. ^ Rebull, Luisa (2011). "Changing Face of the North America Nebula". Spitzer Space Telescope. NASA-JPL. Retrieved 26 August 2020.
  10. ^ Reipurth, Bo (2008). "Star Formation and Young Clusters in Cygnus" (PDF). Astronomical Society of the Pacific. Archived from the original (PDF) on 2019-03-08. Retrieved two September 2020.
  11. ^ a b Comerón, Fernando; Pasquali, Anna (2005). "Discovery of the star that ionizes the North America and Pelican nebulae". Centro Astronómico Hispano-Alemán Newsletter. Centro Astronómico Hispano-Alemán. Retrieved 26 August 2020.
  12. ^ Apellániz1, J. Maíz; Sota2, A. (2016). "The galactic O-star spectroscopic survey (GOSS). 3. 142 boosted O-type systems". The Astrophysical Periodical. IOP Publishing for the American Astronomical Society. Retrieved 26 Baronial 2020.

The Cygnus Wall area of the North America Nebula NGC 7000

Coordinates: Sky map 20h 59m eighteens, +44° 30′ lx″

External links [edit]

  • Media related to Northward America Nebula at Wikimedia Commons
  • The North America Nebula (NGC 7000) at the astro-photography site of Mr. T. Yoshida.
  • NASA APOD: The Due north America and Pelican Nebulae (June xxx, 2009)
  • NASA APOD: The North America Nebula (May ane, 2000)
  • starpointing.com – Central role of the N America Nebula: The Great Wall
  • Creative Eatables Due north America Nebula Data N America Nebula – Creative Commons data Download & editing guide
  • North America Nebula on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, Ten-Ray, Astrophoto, Heaven Map, Articles and images

dildygoisibew66.blogspot.com

Source: https://en.wikipedia.org/wiki/North_America_Nebula

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