White dwarf A white dwarf is the immensely hot dense core into which a star collapses after it has exhausted its nuclear fuel. The presence of Sirius B was deduced by German astronomer Friedrich Besselis in 1844 and observed in 1862 by American telescope-maker and astronomer Alvan Graham Clark; Sirius B was the first white dwarf discovered.
What is the name for the gaseous region of a star which emits light and which extends into a star's surface until the gas becomes opaque?
What is a highly magnetized, rotating, neutron star emitting a beam of electromagnetic radiation that can only be observed when the beam of emission is pointing towards the Earth (known as the lighthouse effect)?
