Star cluster
Alessi 9
Open star cluster · 355 million years
An open cluster of stars born together from the same gas cloud in the Milky Way’s disc; the Galaxy’s tidal forces will disperse it within a few hundred million years. Position, distance, age and member count come from the MWSC catalogue; the total brightness is roughly estimated from the member count.
| Type | Star cluster |
|---|---|
| Constellation | Ara |
| Distance | 218 pc (711.0 ly) |
| Age | 355 million years |
| Member stars (MWSC) | 359 |
| Reddening E(B−V) | 0.10 |
| Metallicity [Fe/H] | -0.58 |
| Source | MWSC (Kharchenko et al. 2013) |
| Right ascension (J2000) | 17h 45m 10.8s |
| Declination (J2000) | −47° 11′ 06″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 43° N. South of latitude 43° S it never sets. It stands highest at midnight in June, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1315. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 13 million years.