The Hubble Space Telescope (HST) has produced a highly-detailed weather map for an alien world, circling another star. This new study produced the most advanced map ever created of the atmosphere of an exoplanet. Astronomers were also able to trace water in the alien atmosphere.
The exoplanet WASP-43b is roughly the size of Jupiter, but contains twice the mass of our solar system's largest member. This massive alien world orbits much closer to its sun than Mercury does in our own family of stars. In fact, WASP-43b orbits so close to its stellar companion that a year on the world lasts a mere 19 hours, one of the shortest periods ever recorded for a massive world.
Because WASP-43b is so close to its sun, it is tidally locked to its companion star, causing one face of the world to eternally point toward its partner. This is similar to the way one face of the Moon is always facing our home world.
Astronomers carried out a pair of studies, designed to uncover secrets of the alien atmosphere. The first of these recorded temperatures in various layers of the atmosphere on WASP-43b. The second measured concentrations of water vapor within the gaseous mixture.
"Our observations are the first of their kind in terms of providing a two- dimensional map of the planet's thermal structure. These maps can be used to constrain circulation models that predict how heat is transported from an exoplanet's hot day side to its cool night side," Kevin Stevenson from University of Chicago, and lead author of the thermal map study, said.
Temperatures on the daytime and nighttime sides of the alien world to vary by hundreds of degrees. On the side of the planet facing the star, temperatures can rise to a scorching 2,700 degrees Fahrenheit, while the dark side of the world cools to a mere 930 degrees. This difference in temperature creates extreme winds that blow from the hot side of the world to the colder hemisphere.
The Hubble Space Telescope instruments were used to eliminate 99.95 percent of the light coming from the companion star to WASP-43b. This allowed astronomers to study electromagnetic radiation produced by the planet, producing a map of the atmosphere across different latitudes. The other study examined light passing through the atmosphere of the planet to study the concentration of water vapor between the two sides of the planet.
A time-lapse video showing how data from WASP-43b changes over the course of a single planetary rotation is available on the University of Chicago Web site.
Study of the abundance of water in the atmosphere of WASP-43b was detailed in The Astrophysical Journal Letters.
