Astronomy crossword

2. newly visible star or nebula
6. when stars convert hydrogen to helium
7. region of cosmic gas and dust formed from the cast off outer layers of dying stars
8. stars become this after they exhausted their nuclear fuel
9. when neutrons cant be packed any close together
10. neutron star with a much stronger magnetic field than ordinary neutron stars
12. 2 stars orbit around a common mass
13. star with mass less than 2 solar masses

1. physical property of a spinning system
3. white dwarfs, neutron stars and black holes
4. pulses of radiation at very regular intervals
5. density of matter so is so high that electrons cant be
6. maximum mass of a stable white dwarf
11. mass flows into the core by the continued formation of iron from nuclear fusion