Thanks for the topic and graphics. "a radius about 1.38 times Jupiter's but contains only half Jupiter's mass" means that somethin's up with HAT-P-1 and/or its discoverers. ;')
A planet this close to a star shouldn't have any ices or gases left; a planet this massive should be a molten ball of iron and silicates with a density greater than 5 g/cc. I would hate to jump to any conclusions...