Supernova
SNR G9.9-0.8
Supernova remnant
The shock wave of a supernova expanding at thousands of kilometres per second: it sweeps up and heats the interstellar gas and shines in radio waves. The distance is estimated from the radio surface-brightness–diameter (Σ–D) relation and may be off by a factor of two.
| Type | Supernova |
|---|---|
| Constellation | Sagittarius |
| Distance | 8,230 pc (26.8 thousand ly) · estimated |
| Diameter | 93.9 ly |
| Type | Shell type |
| Radio flux (1 GHz) | 6.7 Jy |
| Source | Green's SNR Catalogue |
| Right ascension (J2000) | 18h 10m 41.0s |
| Declination (J2000) | −20° 43′ 00″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 69° N. South of latitude 69° 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 27 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 476 million years.