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- Thu Dec 05, 2013 9:17 am
- Forum: The Bridge: Discuss an Astronomy Picture of the Day
- Topic: APOD: Planetary Nebula Abell 7 (2013 Dec 05)
- Replies: 62
- Views: 7156
Re: APOD: Planetary Nebula Abell 7 (2013 Dec 05)
When the explanation says the central star is a 10 billion year old white dwarf, does it mean that it has been a white dwarf that long, or was that when it entered the main sequence? (The nebula being only 20.000 years old suggest the latter...)