
Prerequisite: Must be at least 8th level
The Aasimar can harness their inner divinity to unleash a surge of radiant energy that envelops everything within a 60' ft radius around the Aasimar. All beings, structures or objects must save vs a DC of 15 or take 6d6 radiant damage , or half that is the save is made.
Note: If the damage dealt out is over 30 points, the Aasimir must make a constitution save or fall unconscious for 1d8 turns.
- Must be at least 8th level
- Can be used once in a 48 hour time frame.

Generally, you include restrictions (such as the two long rest limitation you seem to be providing) in the actual feat. Also, this seems like something of a class feature or spell, rather than a feat.