Nebula
RCW 121
H II region
A cloud of ionised hydrogen (H II region): a stellar nursery glowing in the ultraviolet light of the young, hot O and B stars inside it. The distance follows from the gas’s radial velocity and the Galaxy’s rotation curve (kinematic method).
| Type | Nebula |
|---|---|
| Constellation | Scorpius |
| Distance | 13,800 pc (45.0 thousand ly) · estimated |
| Diameter | 126.6 ly |
| WISE name | G348.249-00.971 |
| Catalogue status | Known H II region |
| Source | WISE H II Catalog v3.0 |
| Right ascension (J2000) | 17h 18m 24.8s |
| Declination (J2000) | −39° 18′ 20″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 51° N. South of latitude 51° 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 45 thousand years ago. At that time Homo sapiens was spreading out of Africa; there was no farming yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 798 million years.