Butterfly Cluster (M6, NGC 6405)
The Butterfly Cluster. Credit: AURA, NOAO, NSF.
The Butterfly Cluster (M6, NGC 6405) is an open cluster in the constellation Scorpius, 4° northwest of M7 (Ptolemy's Cluter), that contains about 80 stars roughly in the shape of a butterfly. Visible to the naked eye, it was first noted by Giovanni Hodierna before 1654. Its most conspicuous star is an orange giant K star of magnitude 6.2.
| visual magnitude | 5.3 |
| angular size | 25' |
| diameter | 20 light-years |
| age | about 50 million years |
| distance | 2,000 light-years |
| position | RA 17h 40.1m, Dec -32° 13' |
