What physical process generates a force inside a pre-main-sequence star to offset the force of gravity and stop the star from slowly condensing and shrinking, thus producing a stable, non shrinking main-sequence star?

The type of star does not affect how far away it is.

The strong, and also the weak, nuclear forces only act over very short distances. The strong force hold the nucleons together in a nucleus. They don't have long reaching effect....

First difference is a main sequence star is made of carbon, while a neutron star is made of neutrons. Another difference is a main sequence star still has hydrogen to...

In the core of a main sequence Star temperature and pressure is high enough to undergo hydrogen fusion but it is still not enough to fuse the helium that is...

Stars larger than about 8 solar masses are able to fuse increasingly heavy elements. When its core is mainly iron, then fusion can no longer take place as it requires...

When a star's core fuses all of its hydrogen into helium, the core contracts. The temperature and intense pressure caused by the contractions causes helium to begin fusion in the...

So heat is radiated by large surface area and so the temperature drops..When most of fuel is finished star expands as pull of gravity inwards is reduced,.less temperature means red...

When a star less than 8 solar masses runs out of Hydrogen in its core, the balance between outward pressure and gravity is lost. The core then starts to collapse....

The relationship between a star's distance and its parallax angle is given by $d = 1/p$, where the distance $d$ is measured in parsecs (equal to $3.26$ light years) and...

Ionic bonds occur between anions and cations. And cations may be metallic, i.e., $M^(2+)$, or they may be non-metallic, i.e. ammonium salts, $NH_4^+$. And anions, while typically non-metallic, i.e. $X^-$...