Answer:
the interstellar dust attracting heat away from the protosun.
Step-by-step explanation:
Condensation Theory of the Solar system states that the solar system was formed at about 4.6 billon years ago after nebula reduced in size and flattened out in order to form a circular or oval shape in the form of a disk using interstellar dust particles which consisted of 90% of hydrogen and 9. % of helium particles which attracted heat from the protosun.
The protosun became denser and hotter and experienced gravitational collapse resulting in the formation of the Sun and the Stars. The swirling mass left combined together to form the Planets.