Question

What causes a red giant star's luminosity?

Answer 1

Hey mate

The increasing of temperature in core results in a giant star's luminosity .

Hope it helps..................................!

Answer 2

Answer:

A red giant is a star that has exhausted the supply of hydrogen in its core and has begun thermonuclear fusion of hydrogen in a shell surrounding the core. They have radii tens to hundreds of times larger than that of the Sun. However, their outer envelope is lower in temperature, giving them a reddish-orange hue..