NASA has used two of their space telescopes, Kepler and Spitzer, to construct the first cloud map on an exotic Jupiter-like world, beyond our solar system. The planet in question is Kepler-7b, which was first announced whilst astronomers from the American Astronomical Society were attending a meeting in early 2010.
The findings were published in the Astrophysical Journal Letters, entitled Inference of Inhomogeneous Clouds In An Exoplanet Atmosphere.
Kepler-7b was one of the Kepler spacecraft’s first discoveries. The planet is defined as a hot Jupiter, with a much lower mass than Jupiter, but demonstrating one and a half
times its size. Kepler-7b orbits a star that is significantly larger than our Sun, and completes its orbit every five days at an estimated distance of 0.06 astronomical units.
NASA has previously described the planet as puffy; if it could be placed into a tub of water, they maintain that it would float.
The planet appears to manifest clear skies in the east and high clouds in the west. In the past temperature maps of Kepler-7b have been generated, but this is the very first occasion that cloud structures have been observed and mapped on a distant planet.
Lead author on the paper Brice-Olivier Demory, based at Massachusetts Institute of Technology, Cambridge, talked about his team’s remarkable discovery in a recent press release. Demory claims, by investigating the planet with NASA’s Spitzer and Kepler telescopes, they were able to generate map of the gaseous planet. His research efforts managed to identify a “reflective signature,” which they eventually established to be clouds; using this information, they generated a very low-resolution picture of the cloud formations of Kepler-7b.
Kepler Telescope Observations
The Kepler space telescope was first deployed in 2009 to hunt down Earth-like planets, orbiting their host stars, and was named after the Renaissance astronomer and mathematician Johannes Kepler. Kepler’s sole instrument is a photometer, designed to constantly monitor the
brightness of over 145,000 main sequence stars.
Alas, Kepler’s reaction wheels no longer function appropriately, preventing new observations. However, NASA scientists are still sorting through and analyzing vast amounts of data that had been previously collected by the craft, spanning over four years.
Kepler was used to conduct surveillance of Kepler-7b’s “moon-like phases,” which highlighted an area of brightness in Kepler’s western hemisphere. The bright spot was posited to be one of two likely candidates – a heat source, or cloud formations.
Spitzer Confirms Nature of Bright Spot
With this in mind, NASA began looking towards Spitzer for answers. The Spitzer Space Telescope (SST) was launched in 2003 as an infrared space observatory. As with Kepler, Spitzer is able to observe distant planets, as they orbit around their host stars, providing clues about its atmosphere.
Due to Spitzer’s ability to detect infrared light sources, the spacecraft was able to monitor its temperature, which is approximated to lie between 1,500 and 1,800 degrees Fahrenheit. However, considering Kepler-7b orbits so close to its host star, this temperature range is relatively cool. Once more, NASA scientists believe it is too cool to explain the spot of brightness that Kepler observed.
Noticing this discrepancy, NASA theorizes that Kepler-7b’s bright spot was the host star’s light bouncing off cloud tops in the western hemisphere. These thoughts were echoed by Thomas Barclay, a Kepler scientist at NASA’s Ames Research Center, situated in California. Barclay claims the planet has a “remarkably stable climate,” with cloud patterns remaining fairly static – a feature completely different to that of Earth.
Meanwhile, Paul Hertz, director of the Astrophysics Division, Washington, claimed Spitzer and Kepler represented a “multi-wavelength tool” for more thorough observation of distant planets:
“We’re at a point now in exoplanet science where we are moving beyond just detecting exoplanets, and into the exciting science of understanding them.”
It’s thought that combining the results, collected from NASA’s Kepler and Spitzer telescopes, could aid in the discovery of the atmospheric compositions of other exotic worlds, reaching beyond our solar system.
By: James Fenner
Astrophysical Journal Letters Source