The Sun were twice its actual diameter but still had the same surface temperature? At what wavelength would that new Sun emit its radiation most intensely? How many times brighter would the new Sun be...

The Sun were twice its actual diameter but still had the same surface temperature? At what wavelength would that new Sun emit its radiation most intensely? How many times brighter would the new Sun be than the present Sun? How might things on Earth be different under the bigger Sun?