NASA Maps Climate Patterns on a Super-Earth

The varying brightness of an exoplanet called 55 Cancri e is shown in this plot of infrared data captured by NASA’s Spitzer Space Telescope.

Credits: NASA/JPL-Caltech/University of Cambridge

Spitzer stared at the planet with its infrared vision for a total of 80 hours, watching it orbit all the way around its star multiple times. These data allowed scientists to map temperature changes across the entire planet. To their surprise, they found a dramatic temperature difference of 2,340 degrees Fahrenheit (1,300 Kelvin) from one side of the planet to the other. The hottest side is nearly 4,400 degrees Fahrenheit (2,700 Kelvin), and the coolest is 2,060 degrees Fahrenheit (1,400 Kelvin).

The fact Spitzer found the night side to be significantly colder than the day side means heat is not being distributed around the planet very well. The data argues against the notion that a thick atmosphere and winds are moving heat around the planet as previously thought. Instead, the findings suggest a planet devoid of a massive atmosphere, and possibly hint at a lava world where the lava would become hardened on the night side and unable to transport heat.

“The day side could possibly have rivers of lava and big pools of extremely hot magma, but we think the night side would have solidified lava flows like those found in Hawaii,” said Michael Gillon, University of Liège, Belgium.

The Spitzer data also revealed the hottest spot on the planet has shifted over a bit from where it was expected to be: directly under the blazing star. This shift either indicates some degree of heat recirculation confined to the day side, or points to surface features with extremely high temperatures, such as lava flows.

Additional observations, including from NASA’s upcoming James Webb Space Telescope, will help to confirm the true nature of 55 Cancri e.

The new Spitzer observations of 55 Cancri are more detailed thanks to the telescope’s increased sensitivity to exoplanets. Over the past several years, scientists and engineers have figured out new ways to enhance Spitzer’s ability to measure changes in the brightness of exoplanet systems. One method involves precisely characterizing Spitzer’s detectors, specifically measuring “the sweet spot” — a single pixel on the detector — which was determined to be optimal for exoplanet studies.

“By understanding the characteristics of the instrument — and using novel calibration techniques of a small region of a single pixel — we are attempting to eke out every bit of science possible from a detector that was not designed for this type of high-precision observation,” said Jessica Krick of NASA’s Spitzer Space Science Center, at the California Institute of Technology in Pasadena.

NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

 

 

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