What is a star in astrophysics?

First off, a decent enough astrophysical definition of a star is: any object that is sufficiently massive that it can ignite the fusion of elements in its core due to the gravitational pressures inside the object itself. The smallest object that we know of today that is capable of such feats is around 10% the mass of our sun.

What is the longest phase of a star's life?

Astronomers call stars that are stably undergoing nuclear fusion of hydrogen into helium main sequence stars. This is the longest phase of a star’s life. The star’s luminosity, size, and temperature will slowly change over millions or billions of years during this phase. Our Sun is roughly midway through its main sequence stage.

What is a heartbeat star?

These systems are known as heartbeat stars because of the characteristic shape of the lightcurves. Because solar oscillations are driven by near-surface convection, any stellar oscillations caused similarly are known as solar-like oscillations and the stars themselves as solar-like oscillators.

What is the main sequence of a star?

Instead there is a stripe running diagonally that the vast majority of stars live on. This stripe runs from the dim, red end to the bright, blue end. This stripe is known as the main sequence, and stars that burn hydrogen in their cores (the primary fuel source for the vast majority of a star's life) will live somewhere on this stripe.