This is a massive ball of plasma that shines because of thermonuclear fusion in its core.

A star is an astronomical object that consists of a luminous spheroid of plasma held together by its own gravity.

A star is also a massive ball of plasma that shines because of thermonuclear fusion in its core. A portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses through the interior and eventually radiates to the outer space.