Jump to content
Wikipedia The Free Encyclopedia

Messier 71

From Wikipedia, the free encyclopedia
Globular cluster in the constellation Sagitta
You can help expand this article with text translated from the corresponding article in French. Click [show] for important translation instructions.
  • Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia.
  • Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article.
  • You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing French Wikipedia article at [[:fr:M71 (amas globulaire)]]; see its history for attribution.
  • You may also add the template {{Translated|fr|M71 (amas globulaire)}} to the talk page.
  • For more guidance, see Wikipedia:Translation.
You can help expand this article with text translated from the corresponding article in Italian. Click [show] for important translation instructions.
  • Machine translation, like DeepL or Google Translate, is a useful starting point for translations, but translators must revise errors as necessary and confirm that the translation is accurate, rather than simply copy-pasting machine-translated text into the English Wikipedia.
  • Do not translate text that appears unreliable or low-quality. If possible, verify the text with references provided in the foreign-language article.
  • You must provide copyright attribution in the edit summary accompanying your translation by providing an interlanguage link to the source of your translation. A model attribution edit summary is Content in this edit is translated from the existing Italian Wikipedia article at [[:it:M71 (astronomia)]]; see its history for attribution.
  • You may also add the template {{Translated|it|M71 (astronomia)}} to the talk page.
  • For more guidance, see Wikipedia:Translation.
Messier 71
The globular cluster Messier 71 by the Hubble Space Telescope.
Observation data (J2000 epoch)
Class X-XI
Constellation Sagitta
Right ascension 19h 53m 46.49s[1]
Declination +18° 46′ 45.1″[1]
Distance 13.0 kly (4.0 kpc)[2]
Apparent magnitude (V)8.2[3]
Apparent dimensions (V)7.2'
Physical characteristics
Mass1.7×ばつ104[4]  M☉
Radius13 ly[5]
Metallicity [ Fe / H ] {\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}} {\displaystyle {\begin{smallmatrix}\left[{\ce {Fe}}/{\ce {H}}\right]\end{smallmatrix}}} = –0.78[6] dex
Estimated age9-10 Gyr
Other designationsM71, NGC 6838, Cr 409, GCl 115[7]
See also: Globular cluster, List of globular clusters

Messier 71 (also known as M71, NGC 6838, or the Angelfish Cluster) is a globular cluster in the small northern constellation Sagitta. It was discovered by Philippe Loys de Chéseaux in 1745 and included by Charles Messier in his catalog of non-comet-like objects in 1780. It was also noted by Koehler at Dresden around 1775.[8] Messier 71 is also known as NGC 6839 and The Bernardo Star, though this identification is very uncertain.[9]

This star cluster is about 13,000 light years away from Earth and spans 27 light-years (8 pc). The irregular variable star Z Sagittae is a member.[10]

M71 was for many decades thought (until the 1970s) to be a densely packed open cluster and was classified as such by leading astronomers in the field of star cluster research due to its lacking a dense central compression, and to its stars having more "metals" than is usual for an ancient globular cluster; furthermore, it lacks the RR Lyrae "cluster" variable stars that are common in most globulars. However, modern photometric photometry has detected a short "horizontal branch" in the H-R diagram (chart of temperature versus luminosity) which is characteristic of a globular cluster. The shortness of the branch explains the lack of RR Lyrae variables and is due to the globular's relatively young age of 9–10 billion years. Taking in many or only late series (Population I) stars explains relatively its stars. Hence today M71 is designated as a very loosely concentrated globular cluster, much like M68 in Hydra. M71 has a mass of about 53,000 M☉ and a luminosity of around 19,000 L☉.[11]

Map showing location of M71
Wikimedia Commons has media related to Messier 71 .

See also

[edit ]

References

[edit ]
  1. ^ a b Goldsbury, Ryan; et al. (December 2010), "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters", The Astronomical Journal, 140 (6): 1830–1837, arXiv:1008.2755 , Bibcode:2010AJ....140.1830G, doi:10.1088/0004-6256/140/6/1830, S2CID 119183070.
  2. ^ Hessels, J. W. T.; et al. (November 2007), "A 1.4 GHz Arecibo Survey for Pulsars in Globular Clusters", The Astrophysical Journal, 670 (1): 363–378, arXiv:0707.1602 , Bibcode:2007ApJ...670..363H, doi:10.1086/521780, S2CID 16914232.
  3. ^ "Messier 71". SEDS Messier Catalog. Retrieved 30 April 2022.
  4. ^ Marks, Michael; Kroupa, Pavel (August 2010), "Initial conditions for globular clusters and assembly of the old globular cluster population of the Milky Way", Monthly Notices of the Royal Astronomical Society , 406 (3): 2000–2012, arXiv:1004.2255 , Bibcode:2010MNRAS.406.2000M, doi:10.1111/j.1365-2966.2010.16813.x , S2CID 118652005. Mass is from MPD on Table 1.
  5. ^ distance ×ばつ sin( diameter_angle / 2 ) = 13 ly. radius
  6. ^ Boyles, J.; et al. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal, 742 (1): 51, arXiv:1108.4402 , Bibcode:2011ApJ...742...51B, doi:10.1088/0004-637X/742/1/51, S2CID 118649860.
  7. ^ "M 71". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2006年11月17日.
  8. ^ "New General Catalog Objects: NGC 6800 - 6849". cseligman.com. Retrieved 2021年03月11日.
  9. ^ "Your NED Search Results". ned.ipac.caltech.edu. Retrieved 2024年08月28日.
  10. ^ "Z Sge". The International Variable Star Index. AAVSO. Retrieved 1 March 2021.
  11. ^ Dalgleish, H.; Kamann, S.; Usher, C.; Baumgardt, H.; Bastian, N.; Veitch-Michaelis, J.; Bellini, A.; Martocchia, S.; Da Costa, G. S.; Mackey, D.; Bellstedt, S.; Pastorello, N.; Cerulo, P. (March 2020). "The WAGGS project-III. Discrepant mass-to-light ratios of Galactic globular clusters at high metallicity". Monthly Notices of the Royal Astronomical Society. 492 (3): 3859–3871. arXiv:2001.01810 . Bibcode:2020MNRAS.492.3859D. doi:10.1093/mnras/staa091 .
[edit ]
[edit ]

AltStyle によって変換されたページ (->オリジナル) /