Astronomy:Messier 25
| Messier 25 | |
|---|---|
 Open cluster Messier 25 in Sagittarius | |
| Observation data (J2000.0 epoch) | |
| Right ascension | 18h 31m 47.0s[1] |
| Declination | −19° 07′ 00″[1] |
| Distance | 2,000 ly (620 pc)[2] |
| Apparent magnitude (V) | 4.6[3] |
| Apparent dimensions (V) | 36′[2] |
| Physical characteristics | |
| Mass | 1,937 M☉[4] M☉ |
| Radius | 6.5 light-years[4] |
| Estimated age | 67.6 million years[2] |
| Other designations | Messier 25,[5] IC 4725, Cr 382, C 1828–192, Mel 204 |
Messier 25, also known as IC 4725, is an open cluster of stars in the southern constellation of Sagittarius. The first recorded observation of this cluster was made by Philippe Loys de Chéseaux in 1745 and it was included in Charles Messier's list of nebulous objects in 1764.[6] The cluster is located near some obscuring features, with a dark lane passing near the center.[7]
M25 is at a distance of about 2,000 light-years away from Earth and is 67.6 million years old.[2] The spatial dimension of this cluster is about 13 light-years across. It has an estimated mass of 1,937 M☉, of which about 24% is interstellar matter.[4] A Delta Cephei type variable star designated U Sagittarii is a member of this cluster,[8] as are two red giants, one of which is a binary system.[9]
See also
References
- ↑ 1.0 1.1 Wu, Zhen-Yu et al. (November 2009), "The orbits of open clusters in the Galaxy", Monthly Notices of the Royal Astronomical Society 399 (4): 2146–2164, doi:10.1111/j.1365-2966.2009.15416.x, Bibcode: 2009MNRAS.399.2146W.
- ↑ 2.0 2.1 2.2 2.3 Kharchenko, N. V. et al. (2005), "Astrophysical parameters of Galactic open clusters", Astronomy and Astrophysics 438 (3): 1163–1173, doi:10.1051/0004-6361:20042523, Bibcode: 2005A&A...438.1163K.
- ↑ "Messier 25". https://messier.seds.org/m/m025.html.
- ↑ 4.0 4.1 4.2 Tadross, A. L.; Marie, M. A.; Osman, A. I.; Hassan, S. M. (2002), "Astrometry of the Open Cluster M25", Astrophysics and Space Science 282 (4): 607–623, doi:10.1023/A:1021137115870, Bibcode: 2002Ap&SS.282..607T.
- ↑ "IC 4725". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=IC+4725.
- ↑ Thompson, Robert; Thompson, Barbara (2007), Illustrated Guide to Astronomical Wonders: From Novice to Master Observer, DIY science, O'Reilly Media, Inc., p. 408, ISBN 978-0596526856, https://books.google.com/books?id=ymt9nj_uPhwC&pg=PA408.
- ↑ Landolt, Arlo U. (February 1964), "The Galactic Cluster M25", Astrophysical Journal Supplement 8: 352, doi:10.1086/190093, Bibcode: 1964ApJS....8..352L.
- ↑ Wampler, J. et al. (May 1961), "Cepheids in Galactic Clusters. VIII. a Reinvestigation of U SGR in M25 (= IC 4725)", Astrophysical Journal 133: 895, doi:10.1086/147092, Bibcode: 1961ApJ...133..895W.
- ↑ Mermilliod, J. C. et al. (September 1987), "Membership of cepheids and red giants in 8 open clusters : NGC 129, 6067, 6087, 6649, 6664, IC 4725, LY 6, RU 79", Astronomy and Astrophysics Supplement Series 70: 389–407, Bibcode: 1987A&AS...70..389M.
External links
- Messier 25, The Messier Catalog. Students for the Exploration and Development of Space (SEDS)
- Messier 25 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
- Open Cluster M25. Astronomy Picture of the Day 2009 August 31
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Coordinates: 
18h 31.6m 00s, −19° 15′ 00″
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