NGC 6242

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 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
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]