NGC 6242 | |
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Observation data ( J2000 epoch) | |
Right ascension | 16h 55m 30.7s [1] |
Declination | −39° 28′ 26″ [1] |
Distance | 4.35 ± 0.53 kly (1.335 ± 0.163 kpc) [2] |
Apparent magnitude (V) | 6.4 [3] |
Apparent dimensions (V) | 9 ′ [3] |
Physical characteristics | |
Estimated age | 77.6 [2] Myr |
Other designations | NGC 6242, Cr 317 [4] |
Associations | |
Constellation | Scorpius |
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]
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]