On wild ones I have noticed colored stars and grey stars can someone tell me what do the stars mean? Thank you

I think the color is the rarity of the wild sylesti.
Grey- no traits common
Green- uncommon 1 hidden trait
Blue- rare 1-2 traits
Purple- very rare 2-3 traits

The number of stars is the difficulty. More stars = harder to beat.

Cool thank you

To clarify further:
In the first two Regions, green and blue star pets (can you find epics in those regions?) have +1 trait points (this will change once the site is updated from Beta)
In Astryl's Vale and Fesitval Zones (which run on the updated system)
grey=0tp
green=1 (1 carry)
blue=2 (1vis or 2carry)
purple=4 (2vis / 1vis, 2 carry / 4 carry)
yellow=6
red=8

And yes, it does indicate the rarity of a pet, with yellow- Legendary- being intensely rare, and red- Mystical- feel near enough like once-in-a-lifetime rare (it is really something when you find one)

The number of stars actually is more of an indicator of Mana alongside difficulty
In non-fabled sylesti:
1= 60 mana
2= 80 mana
3= 100 mana
4= 120 mana
5-star opponents cannot be caught, as it's reserved for denoting bosses (120 is the Maximum amount of Mana)
Fabled Sylesti have 20 more base mana than common pets

Thank you