Compel Star

6th Level Coactimancy
Casting Time: 1 action
Range: Self
Components: V S M (a piece of meteorite worth at least 50 gp)
Duration: Instantaneous 
Classes: Sorcerer
You compel the forces of space, and evoke a small, localized solar flare from the nearest star. This spell has no effect if the caster is within a space that has a ceiling or other cover. Pick up to three creatures within 10 feet of the caster. Each of them must make a Constitution Saving throw, as heat surrounds them from above. On a failed save, they take 8d6 Fire Damage, or half on a success. 
Afterwards, each of those targets must make a Dexterity Saving throw, as the solar flare arrives and attempts to burn them. On a failed save, they take an additional 8d6 fire damage, and are knocked prone. On a success, the targets take half as much damage and are not knocked prone.