Well when we google it this is what comes up:
A cloud collapses to form a star and disk. Planets form from this disk. According to our current understanding, a star and its planets form out of a collapsing cloud of dust and gas within a larger cloud called a nebula.
In stellar metamorphosis here is what it actually should look like:
A cloud is ionized forming a young star. This young star cools and collapses into what is called a planet. According to our current understanding, a star is a young planet and a planet is an ancient star, thus they are the same objects.
As we can see the problem was that they needed a unifying concept to combine both stars and planets. Little do they know the star is the new planet and the planet is the ancient star. The disk was never needed.
I have outlined these assumptions: