مسييه 5

مسييه 5
Messier 5
مسييه 5 بواسطة تلسكوب الفضاء هبل. 2.85′ view
الفضل: ناسا/STScI/WikiSky
بيانات الرصد
ClassV[1]
كوكبةالحية
Right ascension15س 18د 33.22ث[2]
Declination+02° 04′ 51.7″[2]
المسافة24.5 kly (7.5 kpc)[3]
Apparent magnitude (V)+6.65[4]
Apparent dimensions (V)23′.0
السمات الطبيعية
Mass8.57×105[5] M☉
نصف القطر80 ly
Metallicity–1.12[6] dex
العمر المقدّر10.62 Gyr[6]
تسميات أخرىإن جي سي 5904[4]
See also: Globular cluster, List of globular clusters

مسييه 5 هي عبارة عن تجمع كروي يقع في كوكبة الثعبان . وهذا التجمع هو واحد من التجمعات الكروية القليلة التي تشاهد في شكل بيضوي أو اهليجي . وهذا التجمع يتعقد انه واحد من أقدم التجمعات الكروية حيث يبلغ عمرها حوالي 13 مليار سنه.

تقع على بعد 23.000 سنه ضوئية من الكرة الأرضية ويبلغ قطرها حوالي 130 سنه ضوئية ، ومقدار لمعانه 5.6 ماغ

الاكتشاف وإمكانية الرؤية

M5 is, under extremely good conditions, just visible to the naked eye as a faint "star" 0.37 of a degree (22' (arcmin)) north-west of star 5 Serpentis. Binoculars and/or small telescopes resolve the object as non-stellar; larger telescopes will show some individual stars, some of which are as bright as apparent magnitude 10.6.[7] M5 was discovered by German astronomer Gottfried Kirch in 1702 when he was observing a comet. Charles Messier noted it in 1764 and—a studier of comets—cast it as one of his nebulae. William Herschel was the first to resolve individual stars in the cluster in 1791, counting roughly 200.[8] Messier 5 is receding from the Solar System at a speed over 50 km/s.[9]

سمات ملحوظة

M5 wide angle by Robert J. Vanderbei
M5 photographed with a DSLR camera.

Within M5, there are 105 known variable stars, 97 of them belonging to the RR Lyrae type.[10] RR Lyrae stars, sometimes referred to as "Cluster Variables", are somewhat similar to Cepheid type variables and as such can be used as a tool to measure distances in outer space since the relation between their luminosities and periods are well known. The brightest and most easily observed variable in M5 varies from magnitude 10.6 to 12.1 in a period of just under 26.5 days.[7]

The cluster contains two millisecond pulsars, one of which is in a binary, allowing the proper motion of the cluster to be measured. The binary could help our understanding of neutron degenerate matter; the current median mass, if confirmed, would exclude any "soft" equation of state for such matter.[11] The cluster has been used to test for magnetic dipole moments in neutrinos, which could shed light on some hypothetical particles such as the axion.[12]

A dwarf nova has also been observed in this cluster.[13]

المصادر

  1. ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), "A Classification of Globular Clusters", Harvard College Observatory Bulletin (849): 11–14, Bibcode: 1927BHarO.849...11S. 
  2. ^ أ ب Goldsbury, Ryan; Richer, Harvey B.; Anderson, Jay; Dotter, Aaron; Sarajedini, Ata; Woodley, Kristin (December 2010), "The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters", The Astronomical Journal 140 (6): 1830–1837, doi:10.1088/0004-6256/140/6/1830, Bibcode: 2010AJ....140.1830G. 
  3. ^ Paust, Nathaniel E. Q.; Reid, I. Neill; Piotto, Giampaolo; Aparicio, Antonio; Anderson, Jay; Sarajedini, Ata; Bedin, Luigi R.; Chaboyer, Brian; et al. (February 2010), "The ACS Survey of Galactic Globular Clusters. VIII. Effects of Environment on Globular Cluster Global Mass Functions", The Astronomical Journal 139 (2): 476–491, doi:10.1088/0004-6256/139/2/476, Bibcode: 2010AJ....139..476P. 
  4. ^ أ ب "Messier 5". SIMBAD Astronomical Database. Retrieved 2006-11-15.
  5. ^ Boyles, J.; Lorimer, D. R.; Turk, P. J.; Mnatsakanov, R.; Lynch, R. S.; Ransom, S. M.; Freire, P. C.; Belczynski, K. (November 2011), "Young Radio Pulsars in Galactic Globular Clusters", The Astrophysical Journal 742 (1): 51, doi:10.1088/0004-637X/742/1/51, Bibcode: 2011ApJ...742...51B. 
  6. ^ أ ب Forbes, Duncan A.; Bridges, Terry (May 2010), "Accreted versus in situ Milky Way globular clusters", Monthly Notices of the Royal Astronomical Society 404 (3): 1203–1214, doi:10.1111/j.1365-2966.2010.16373.x, Bibcode: 2010MNRAS.404.1203F. 
  7. ^ أ ب خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة CouttsClement
  8. ^ خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة Herschel
  9. ^ Harris, William E. (1996). "A Catalog of Parameters for Globular Clusters in the Milky Way". The Astronomical Journal. 112: 1487. Bibcode:1996AJ....112.1487H. doi:10.1086/118116.
  10. ^ Szeidl, B.; Hurta, Zs.; Jurcsik, J.; Clement, C.; Lovas, M. (2011). "Long-term photometric monitoring of Messier 5 variables – I. Period changes of RR Lyrae stars". Monthly Notices of the Royal Astronomical Society. 411 (3): 1744–1762. arXiv:1010.1115. Bibcode:2011MNRAS.411.1744S. doi:10.1111/j.1365-2966.2010.17815.x. S2CID 118519067.
  11. ^ Freire, P. C. C.; Wolszczan, A.; van den Berg, M.; Hessels, J. W. T. (2008). "A Massive Neutron Star in the Globular Cluster M5". The Astrophysical Journal. 679 (2): 1433–1442. arXiv:0712.3826. Bibcode:2008ApJ...679.1433F. doi:10.1086/587832. S2CID 118743395.
  12. ^ Viaux, N.; Catelan, M.; Stetson, P. B.; Raffelt, G. G.; Redondo, J.; Valcarce, A. A. R.; Weiss, A. (2013). "Particle-physics constraints from the globular cluster M5: Neutrino dipole moments". Astronomy & Astrophysics. 558: A12. arXiv:1308.4627. Bibcode:2013A&A...558A..12V. doi:10.1051/0004-6361/201322004. S2CID 59056210.
  13. ^ خطأ استشهاد: وسم <ref> غير صحيح؛ لا نص تم توفيره للمراجع المسماة Neill

وصلات خارجية

 هذه بذرة مقالة عن الفضاء الخارجي تحتاج للنمو والتحسين، ساهم في إثرائها بالمشاركة في تحريرها.

الإحداثيات: خريطة السماء 15س 18ق 33.75ث, +02° 04′ 57.7″

تمّ الاسترجاع من "https://www.marefa.org/w/index.php?title=مسييه_5&oldid=4307021"