a very large star of high luminosity and low surface temperature, thought to be in a late stage of evolution when no hydrogen remains in the core to fuel nuclear fusion.

the largest stars in the universe in terms of volume, although they are not the most massive or luminous.

a star that suddenly increases greatly in brightness because of a catastrophic explosion that ejects most of its mass.

a celestial object of very small radius and very high density, composed predominantly of closely packed neutrons

a region of space having a gravitational field so intense that no matter or radiation can escape.

quantity of matter in a physical body.

the intrinsic brightness of a celestial object.

the force that attracts a body toward the center of the earth, or toward any other physical body having mass.

the implosion of a star or other celestial body as a result of its own gravity, resulting in a body that is many times smaller and denser than the original body.

stars with masses greater than three times the mass of the Sun-- are the largest, hottest and brightest Main Sequence stars and blue, blue-white or white in colour.

stars with masses less than half the mass of the Sun-- are the smallest, coolest and dimmest Main Sequence stars and orange, red or brown in colour.

metal with high densities, high atomic weights, and high atomic numbers.

a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.