Match the following definitions to the correct key term. 1. a variable radio source of small physical size that emits very rapid radio pulses in very regular periods that range from fractions of a second to several seconds; 2. a compact object of extremely high density composed almost entirely of neutrons 3. a stellar explosion produced at the endpoint of the evolution of stars whose mass exceeds roughly 10 times the mass of the Sun 4. the upper limit to the mass of a white dwarf 5. a gas that resists further compression because no two electrons can be in the same place at the same time doing the same thing 6. the cataclysmic explosion produced in a binary system, temporarily increasing its luminosity by hundreds to thousands of times 7. a pulsar that rotates so quickly that it can give off hundreds of pulses per second Terms: neutron star Pulsar black hole millisecond pulsar Chandrasekhar limit nova type II supernova hydrogen gas type Ia Supernova