What does Aarush mean?
From Sanskrit arusha (आरुष), 'reddish, red of dawn', commonly glossed as 'the first ray of the sun'. The 'red/dawn' sense is the attested one; 'first ray of sun' is the popular reading.
What does Vivaan mean?
Commonly glossed as 'the first rays of the morning sun' and associated with Surya (the sun). It is a modern Sanskrit-derived name; the popular claim that it is an epithet of Krishna rests on weak sources, so treat that association cautiously.