Planet Provokes a Star’s Pulse

Discovery of a pulsating star that hosts a giant planet

‘Hot Jupiters’ are not thought to be capable of supporting life, but studying them provides information on the multitude of unique planetary systems that exist. Such studies also help improve techniques for spotting and analyzing extrasolar planets. Image Credit: ESA/C Carreau


WASP-33 (also known as HD15082) is hotter, more massive than the Sun (1.5 Msun) and is located at a distance of 378 light years away, in the constellation of Andromeda. It has the peculiarity of being a star that pulsates radially, like a balloon that inflates and deflates continuously, and non-radially, like the tides in Earth‘s oceans caused by the presence of the Moon, which deforms the bodies of water between the poles and the equator.

This star hosts a giant planet, WASP-33b, that was detected in 2006 through the transiting method. The planet’s mass is four times the mass of Jupiter and it orbits the star at such a high speed that it only takes 1.2 days to complete its orbit. This very short orbital period indicates its extreme proximity to the star, 0.02 astronomical units (AU) when Mercury, the closest planet to the Sun, is at 0.39 AU. This planet is quite particular because it has a retrograde orbit and, evenmore, its orbit is quite inclined in angle respect to the star’s equator.

WASP-33 is thought to be even hotter and more massive than the Sun. Image Credit: NASA Goddard Space Flight Center



Therefore, the WASP-33 system represents a landmark in the world of exoplanets since it may provide vital information on pulsations modes that occur in stars, the effects of tides between stars and planets and the dynamical evolution of planetary systems. Information about the types of planetary systems that exist in the Universe is valuable for astrobiologists who are trying to determine where best to search for habitable, extrasolar worlds.