HM 1
| HM 1 (Havlen-Moffat 1) | |
|---|---|
Approximate location of HM 1 (circled) | |
| Observation data (J2000 epoch) | |
| Right ascension | 17h 18m 54s |
| Declination | −38° 49′ 01″ |
| Distance | 9,500–12,700 ly (2,900–3,900 pc) |
| Apparent dimensions (V) | 5′ |
| Physical characteristics | |
| Estimated age | 1–2 Myr 2–4 Myr |
| Star cluster rich in massive stars | |
| Other designations | C 1715-387 |
| Associations | |
| Constellation | Scorpius |
HM 1, also known as Havlen-Moffat 1, is an open cluster located in the constellation of Scorpius, close to the galactic plane. It was first observed by R. J. Havlen and A. F. J. Moffat in 1976. HM 1 is thought to be 9,500 to 12,700 light-years (2,900 to 3,900 parsecs) away from the Earth, beyond the Carina–Sagittarius Arm. It is heavily reddened by interstellar extinction, so although it comprises mostly blue-colored stars, it appears brighter for longer-wavelength passbands. It is projected against the H II region known as RCW 121, and appears to be the source of ionization for the nearby regions RCW 122 and RCW 123.