ASTR 1102 Lecture : Lecture25
Document Summary
The energy of a pulsar comes from the neutron star"s rotation. This is what excites the inner crab nebula. Neutron star slows down, magnetic field decays. But only slows down gradually - appears old. Each star has a zone dominated by its gravity. Inner lagrangian point is point at which both stars pull equally. If one star expands to fill its roche lobe, gas can overflow onto the other star. The gas is rotating, so forms an accretion disk. This gas is eventually accreted by the small star. Black hole accreting from an f-type sub-giant. More massive star evolves and loses envelope as planetary nebula. Leaves binary of normal star and white dwarf. If it does, can leave x-ray binary - normal star accreting onto black hole or neutron star. Some pulsars are undetected in radio, but emit pulsed x-rays. Gas tries to accrete onto neutron star. Neutron star magnetic field can control flow of ionized gas.
