Janssen has a thick blue atmosphere, covering his red lava ocean surface. Janssen has a mouthpiece, with white quadrilateral eyes and a blue outline, and a cyan sclera. His left arm is blue while his right arm is black, with both hands covered in cracks of lava. Janssen's surface rains diamonds on its surface similar to Neptune, which rains diamonds below its cloud surface, and is thus an analogue of Neptune. Janssen is most likely a carbon planet.