Lecture 10 - Neutron Stars and Pulsars Flashcards
(20 cards)
what balances the life of a star?
the push from fusion energy against the pull of gravity
what occurs when a star runs out of fuel?
gravity wins, leading to the star losing its outer envelope via explosion and leaving behind a collapsed core.
what determines the type of compact object formed from a star’s collapse?
the mass of the collapsed core Mc
what forms when MC is less than 1.4 solar masses?
white dwarf, made mostly of electron-degenerate matter
what forms between 1.4 and 3 Mc?
neutron star, gravity strong enough that it crushes protons and electrons in neutrons
what happens when Mc is greater than 3?
collapses into a black hole
what is the Pauli Exclusion principle?
no two fermions can occupy the same quantum state in the same region of space
what is electron capture in neutron star?
the interaction where protons and electrons combine to produce neutrons and neutrinos
what is the Chandrasekhar Mass limit?
theoretical limit of 1.4 solar masses
how are neutron stars typically measured?
observing neutron stars in binary systems and using Kepler’s Laws to estimate mass from orbital periods
what are the properties of neutron stars?
compact objects held up by neutron degeneracy, 20 km in diameter, mass of about 4.5 suns, very dense
what is the escape speed of neutron stars?
half the speed of light
what characterises the magentic fields of neutron stars?
billiion times strong than earth’s magentic field and are not aligned with the rotation axis
what is a pulsar?
pulsating radio star that emits beams of radiation from its magentic poles
what is a millisecond pulsar?
a pulsar that roates hundreds of times per second, often found in binary systems
how do millisecond pulsars maintain their roation speed?
gain angular momentum from material transferred from a companion star
what effect do gravitational waves have on milisecond pulsars?
change the timing period of the pulsar by a few nanoseconds, allowing detection of the waves
what is the significance of stable emission from milisecond pulsars?
it provides accurate timing on a nansecond scale, aiding the understanding of gravity
what happens to pulsars dur to energy loss from diple radiation?
slow down over time
what role do neutrinos play in supernova explosions?
produced in vast quantities during electron capture and can be detected befere light from the explosion reaches us
