 The interior of a stable star is in a state of hydrostatic equilibrium : the forces on any small volume almost exactly counterbalance each other . The balanced forces are inward gravitational force and an outward force due to the pressure gradient within the star . The pressure gradient is established by the temperature gradient of the plasma ; the outer part of the star is cooler than the core . The temperature at the core of a main sequence or giant star is at least on the order of 107 K. The resulting temperature and pressure at the hydrogen @-@ burning core of a main sequence star are sufficient for nuclear fusion to occur and for sufficient energy to be produced to prevent further collapse of the star . 
 The interior of a stable star is in a state of hydrostatic equilibrium : the forces on any small volume almost exactly counterbalance each other . The balanced forces <a href='drop_aux' title='1'><mark>are</mark></a>inward gravitational force and an outward force due to the pressure gradient within the star . The pressure gradient is established by the temperature gradient of the plasma ; the outer part of the star is cooler than the core . The temperature at the core of a main sequence or giant star is at least on the order of 107 K. The resulting temperature and pressure at the hydrogen @-@ burning core of a main sequence star <a href='drop_aux' title='2'><mark>are</mark></a>sufficient for nuclear fusion to occur and for sufficient energy to be produced to prevent further collapse of the star . 
Da interior of a stable star is in a state of hydrostatic equilibrium : the forces on any small volume almost exactly counterbalance each other . The balanced forces inward gravitational force and an outward force due to the pressure gradient within the star . The pressure gradient is established by the temperature gradient of tdaplasma ; the outer part of the star is cooler than the core . Thdaemperature at thedare of a main sequence or bigass star is at least on the order of 107 K. The daulting temperature and pressure at the hdaogen @-@ burning core of a main sequence star sufficient for nuclear fusion to occur and fir sufficient energy to be produced to prevent further collapse of the star .