NGC 2539

NGC 2539 is an open cluster in the constellation Puppis, located at the north edge of the constellation. It was discovered by William Herschel on January 31, 1785. It is a moderately rich cluster and with little central concentration, with Trumpler class II1m.

NGC 2539
NGC 2539
Observation data (J2000 epoch)
ConstellationPuppis
Right ascension 08h 10m 37s[1]
Declination−12° 49′ 06″[1]
Distance4,440 ly (1,363 pc[2])
Apparent magnitude (V)6.5 [1]
Apparent dimensions (V)15'
Physical characteristics
Mass5,480[3] M☉
Estimated age370 million years[2]
Other designationsCr 176, Mel 83

Characteristics

The diameter of the cluster based on the location of possible members is estimated to be 7.4 parsecs (24 light years).[4] The core radius of the cluster is 1.98 parsecs (6.5 light years), while the tidal radius is 15.2 parsecs (50 light years) and represents the average outer limit of NGC 2539, beyond which a star is unlikely to remain gravitationally bound to the cluster core.[5] 151 stars, probable members of the cluster, are located within the central part of the cluster and 455 probable members are located within the angular radius of the cluster.[5] 19 Puppis, visible near the edge of the cluster is a foreground star.[6] The turn-off mass of the cluster is at 3.1 M☉. The metallicity of the cluster is 0.14, higher than the solar one.[7] The age of the cluster has been estimated to be as high as 630 myrs.[8][4]

Mermilliod and Mayor studied 11 red giants within the cluster, the brightest of which was mag 9.509 and of spectral type K5I-II, and two non-members. Three of this stars were found to be spectrographic binaries, while further studies indicated that one of them is a triple system. Two more are suspected double stars.[9][10] Further studies revealed seven variable stars, 5 eclipsing binaries, one delta Scuti variable and one gamma Doradus variable, with the gamma Doratus variable star membership being questionable. From the eclipsing binaries, one is field star[11] and in a further study one more eclipsing binary (specifically a W Ursae Majoris variable) was found to lie at the background.[12]

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References
  1. "NGC 2539". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2015-06-19.
  2. WEBDA: NGC 2539
  3. Piskunov, A. E.; Schilbach, E.; Kharchenko, N. V.; Röser, S.; Scholz, R.-D. (6 November 2007). "Tidal radii and masses of open clusters". Astronomy & Astrophysics. 477 (1): 165–172. Bibcode:2008A&A...477..165P. doi:10.1051/0004-6361:20078525.
  4. Lapasset, E.; Clariá, J. J.; Mermilliod, J.-C. (September 2000). "UBV photometric study and basic parameters of the southern open cluster NGC 2539". Astronomy and Astrophysics. 361: 945–951. Bibcode:2000A&A...361..945L.
  5. Kharchenko, N. V.; Piskunov, A. E.; Schilbach, E.; Röser, S.; Scholz, R.-D. (3 October 2013). "Global survey of star clusters in the Milky Way". Astronomy & Astrophysics. 558: A53. arXiv:1308.5822. Bibcode:2013A&A...558A..53K. doi:10.1051/0004-6361/201322302.
  6. "NGC 2539 in Puppis". jthommes.com.
  7. Reddy, A. B. S.; Giridhar, S.; Lambert, D. L. (11 April 2013). "Comprehensive abundance analysis of red giants in the open clusters NGC 2527, 2682, 2482, 2539, 2335, 2251 and 2266". Monthly Notices of the Royal Astronomical Society. 431 (4): 3338–3348. arXiv:1303.1104. Bibcode:2013MNRAS.431.3338R. doi:10.1093/mnras/stt412.
  8. Choo, K. J.; Kim, S.-L.; Yoon, T. S.; Chun, M.-Y.; Sung, H.; Park, B.-G.; Ann, H. B.; Lee, M. G.; Jeon, Y.-B.; Yuk, I.-S. (5 February 2003). "Search for variable stars in the open cluster NGC 2539". Astronomy & Astrophysics. 399 (1): 99–104. Bibcode:2003A&A...399...99C. doi:10.1051/0004-6361:20021704.
  9. Mermilliod, J.-C.; Andersen, J.; Latham, D. W.; Mayor, M. (23 July 2007). "Red giants in open clusters". Astronomy & Astrophysics. 473 (3): 829–845. Bibcode:2007A&A...473..829M. doi:10.1051/0004-6361:20078007.
  10. Mermilliod, J. C.; Mayor, M. (July 1989). "Red giants in open clusters. I. Binarity and stellar evolution in five Hyades-generation clusters : NGC 2447, 2539, 2632, 6633 and 6940". Astronomy and Astrophysics. 219: 125–141. Bibcode:1989A&A...219..125M.
  11. Choo, K. J.; Kim, S.-L.; Yoon, T. S.; Chun, M.-Y.; Sung, H.; Park, B.-G.; Ann, H. B.; Lee, M. G.; Jeon, Y.-B.; Yuk, I.-S. (5 February 2003). "Search for variable stars in the open cluster NGC 2539". Astronomy & Astrophysics. 399 (1): 99–104. Bibcode:2003A&A...399...99C. doi:10.1051/0004-6361:20021704.
  12. Kiron, Y. Ravi; Sriram, K.; Vivekananda Rao, P. (March 2012). "A photometric study of contact binaries V3 and V4 in NGC 2539". Bulletin of the Astronomical Society of India. 40: 51. Bibcode:2012BASI...40...51K.


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