Free Astronomy Magazine July-August 2024

JULY-AUGUST 2024 ing that none of the obser- vations we’ve been getting have robustly solved these mys- teries. I am thrilled that we’re finally get- ting some answers!” Un- like the atmospheres of gas giant planets, which are relatively easy to spot (the first was detected by NASA’s Hubble Space Telescope more than two decades ago), thinner and denser at- mospheres surrounding rocky plan- ets have remained elusive. Previous studies of 55 Cancri e us- ing data from NASA’s now-retired Spitzer Space Telescope suggested the presence of a substantial atmos- phere rich in volatiles (molecules that occur in gas form on Earth) like oxygen, nitrogen, and carbon diox- ide. But researchers could not rule out another possibility: that the planet is bare, save for a tenuous shroud of vaporized rock, rich in elements like silicon, iron, alu- minum, and calcium. “The planet is so hot that some of the molten rock should evaporate,” explained Hu. To distinguish between the two possibilities, the team used Webb’s N I R C am (Near-Infrared Camera) and MIRI (Mid-In- frared Instrument) to measure 4- to 12-micron infrared light coming from the planet. Although Webb cannot capture a direct image of 55 Cancri e, it can measure subtle changes in light from the system as the planet orbits the star. T his artist’s concept shows what the exoplanet 55 Cancri e could look like. [NASA, ESA, CSA, Ralf Crawford (STScI)]