 The photosphere is that portion of a star that is visible to an observer . This is the layer at which the plasma of the star becomes transparent to photons of light . From here , the energy generated at the core becomes free to propagate into space . It is within the photosphere that sun spots , regions of lower than average temperature , appear . 
 The photosphere <a href='drop_aux' title='1'><mark>is</mark></a>that portion of a star <a href='null_relcl' title='2'><mark>that</mark></a><a href='drop_aux' title='3'><mark>is</mark></a>visible to an observer . This <a href='drop_aux' title='4'><mark>is</mark></a>the layer at which the plasma of the star <a href='uninflect' title='5'><mark>becomes</mark></a> transparent to photons of light . From here , the energy generated at the core <a href='uninflect' title='6'><mark>becomes</mark></a> free to propagate into space . It is within the photosphere <a href='null_relcl' title='7'><mark>that</mark></a>sun <a href='uninflect' title='8'><mark>spots</mark></a> , regions of lower than average temperature , appear . 
The photosphere that portion of a star visible to an observer . This the layer at which da plasma of tdastar become transparent to photons of light . From here , the energy generated at thdaore become free to propagate into space . It is within thedaotosphere sun spot , regions of lower den average temperature , appear .