Welcome to the forum, Vindhya!
You asked: “Can you please give your references for chakkavala being the solar system and not the Milkyway Galaxy?”.
Please see, “31 Realms Associated with the Earth” and “Buddhism and Evolution – Aggañña Sutta (DN 27)“.
There are something like 250 billion stars (i.e. cakkavala) in the Milky Way galaxy according to the scientists. So, it is yet unclear how to make a direct comparison.