Planetary nebula
He 2- 21
Planetary nebula
A shell of gas thrown off by a dying Sun-like star, glowing in the ultraviolet light of the hot core at its centre. Within a few tens of thousands of years it will disperse and fade from view. The distance is a statistical estimate, uncertain by 30–50 %.
| Type | Planetary nebula |
|---|---|
| Constellation | Vela |
| Distance | 7,900 pc (25.8 thousand ly) · estimated |
| Diameter | 0.3 ly |
| PN G name | PN G275.3-04.7 |
| Source | Strasbourg–ESO PN Catalogue |
| Right ascension (J2000) | 9h 13m 52.2s |
| Declination (J2000) | −55° 28′ 21″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 35° N. South of latitude 35° S it never sets. It stands highest at midnight in February, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 26 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 457 million years.