yeah, It's not so visible on the image here. I'm pretty new to corona myself, but the antialiasing issues you might be experiencing there are most definitely due to overbright pixels. You could try and clamp max intensity... there was a setting for that. Also, letting it render for a longer time should add more AA samples.
If all else fails, you could try to mask the jagged edges by adding bloom to you render, that's available either corona render settings, or you could do it during post-process.