NGC 6242 is an open cluster of stars in the southern constellation Scorpius. It can be viewed with binoculars or a telescope at about 1.5° to the south-southeast of the double star Mu Scorpii.[3] This cluster was discovered by French astronomer Nicolas-Louis de Lacaille in 1752 from South Africa.[5] It is located at a distance of approximately 4,350 ly (1,335 pc) from the Sun,[2] just to the north of the Sco OB 1 association.[6] The cluster has an estimated age of 77.6 million years.[2]

NGC 6242
NGC 6242
Credit: DECaPS
Observation data (J2000 epoch)
Right ascension16h 55m 30.7s[1]
Declination−39° 28′ 26″[1]
Distance4.35 ± 0.53 kly (1.335 ± 0.163 kpc)[2]
Apparent magnitude (V)6.4[3]
Apparent dimensions (V)9[3]
Physical characteristics
Estimated age77.6[2] Myr
Other designationsNGC 6242, Cr 317[4]
Associations
ConstellationScorpius
See also: Open cluster, List of open clusters
Map showing the location of NGC 6242

A microquasar with the designation GRO J1655-40 is located in the vicinity of NGC 6242 and is moving away from the cluster with a runaway space velocity of 112±18 km/s. It may have originated in the cluster during a supernova explosion ~2.2×105 year ago.[7]

References

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  1. ^ a b Tarricq, Y.; et al. (March 2021). "3D kinematics and age distribution of the open cluster population". Astronomy & Astrophysics. 647. id. A19. arXiv:2012.04017. Bibcode:2021A&A...647A..19T. doi:10.1051/0004-6361/202039388.
  2. ^ a b c d Spina, L.; et al. (2021). "The GALAH survey: Tracing the Galactic disc with open clusters". Monthly Notices of the Royal Astronomical Society. 503 (3): 3279. arXiv:2011.02533. Bibcode:2021MNRAS.503.3279S. doi:10.1093/mnras/stab471.
  3. ^ a b c Crossen, Craig; Rhemann, Gerald (2012). Sky Vistas, Astronomy for Binoculars and Richest-Field Telescopes. Springer Vienna. p. 52. ISBN 9783709106266.
  4. ^ "NGC 6242". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2007-04-24.
  5. ^ Jones, K. G. (March 1969). "The search for the nebulae - VI". Journal of the British Astronomical Association. 79: 213–222. Bibcode:1969JBAA...79..213J.
  6. ^ Sana, H.; et al. (August 2006). "An XMM-Newton view of the young open cluster NGC 6231. I. The catalogue". Astronomy and Astrophysics. 454 (3): 1047–1063. arXiv:astro-ph/0603783. Bibcode:2006A&A...454.1047S. doi:10.1051/0004-6361:20053224.
  7. ^ Combi, J. A.; et al. (May 2007). "New evidence on the origin of the microquasar GRO J1655-40". Astronomy and Astrophysics. 467 (2): 597–602. arXiv:astro-ph/0703674. Bibcode:2007A&A...467..597C. doi:10.1051/0004-6361:20077156.
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