Planetary nebula
NGC 7139
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.
| Type | Planetary nebula |
|---|---|
| Constellation | Cepheus |
| Distance | 800 pc (2.6 thousand ly) |
| Diameter | 1.0 ly |
| Central star | V 18.7 |
| Expansion speed | 20 km/s |
| PN G name | PN G104.1+07.9 |
| Source | Strasbourg–ESO PN Catalogue |
| Right ascension (J2000) | 21h 46m 10.2s |
| Declination (J2000) | +63° 47′ 15″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 26° S. North of latitude 26° N it never sets. It stands highest at midnight in August, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out around 584 BC. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 46 million years.