Planetary nebula
A 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 | Gemini |
| Distance | 240 pc (782.8 ly) · estimated |
| Diameter | 2.3 ly |
| Central star | V 16.0 |
| Expansion speed | 64 km/s |
| PN G name | PN G205.1+14.2 |
| Source | Strasbourg–ESO PN Catalogue |
| Right ascension (J2000) | 7h 29m 02.9s |
| Declination (J2000) | +13° 14′ 30″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 77° S. North of latitude 77° N it never sets. It stands highest at midnight in January, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around the year 1243. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 14 million years.