Physics

X-rays must be observed from above atmosphere

Sun-like stars don't emit many X-rays

[Slides on the balloons used to get above the atmosphere]

X-ray binaries: matter goes from donor to neutron star, falling

at high velocity -> heats up star, so spectrum is primarily X-ray

Rotating; when x-ray beam hits earth, we see pulse

They now use satellites instead of balloons

X-ray bursts from thermonuclear fusion explosions on surfaces of neutron

stars. Also causes visible flashes because x-rays heat surrounding gas. Delay

between X-ray and optical flash allows measurement of gas disk.