Planetary nebula
A 51
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 | Sagittarius |
| Distance | 1,990 pc (6.5 thousand ly) · estimated |
| Diameter | 2.1 ly |
| Central star | V 15.4 · sd O8k |
| Expansion speed | 42 km/s |
| PN G name | PN G017.6-10.2 |
| Source | Strasbourg–ESO PN Catalogue |
| Right ascension (J2000) | 19h 01m 01.1s |
| Declination (J2000) | −18° 12′ 15″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 72° N. South of latitude 72° S it never sets. It stands highest at midnight in July, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 6,491 years ago. At that time the first farming villages were being founded; there was no writing yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 115 million years.