2024-05-14 03:47:12
55 Cancri e is a very fiery world to say the least. Classified as a rocky ‘super-Earth‘, this exoplanet is twice the diameter of Earth and orbits its star at just 4% distance. the distance between Mercury and the Sun. 55 Cancri e’s surface is probably covered by a sea of molten magma, and the ambient temperature is hot enough to melt iron.
Since 2004 was this planet, scientists are interested in various aspects of its existence: orbital period, density, and most of all, its atmosphere. At first, researchers weren’t sure if this exoplanet could even have an atmosphere: some thought it was simply too hot and too close to its star. But new data from JWST suggests that 55 Cancri e is indeed covered by a layer of gas—albeit an unusual one.
The first hint that this extremely hot super-Earth has an atmosphere came from an unusual temperature measurement. Using JWST’s Mid-Infrared Instrument (MIRI), the researchers measured the thermal radiation of the dayside of 55 Cancri e. If the planet had no atmosphere, its daily temperature would rise to about 2,200 degrees Celsius. But that’s not what MIRI found.
“Instead, the MIRI data showed a relatively low temperature of around 1,500 °C,” – says the study’s lead author, NASA Jet Propulsion Laboratory astronomer Renyu Hu. These data suggest that something – most likely an atmospheric current – is transporting heat from the dayside to the nightside of the planet.
Next, Hu’s team used the Near Infrared Spectroscopy Camera (NIRCam) instrument to determine what elements might be present in this suspected atmosphere. They found evidence of carbon dioxide or carbon monoxide gas swirling around the planet’s molten rock surface.
However, scientists suspect that this gaseous layer has not been present since the planet formed, an atmosphere that would have been quickly and violently disrupted by the solar wind from a nearby star. They believe that the carbon-rich “secondary atmosphere” rather erupted from the interior of the planet. This would allow the atmosphere to continually renew itself, even as the gas dissipates.
Study co-author Diana Dragomir, an exoplanet researcher at the University of New Mexico who has been studying 55 Cancri e for more than 10 years, is particularly impressed with the results. “It was very disappointing that none of the observations we received firmly resolved these mysteries,” she says. “I’m glad we finally got some answers!”
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2024-05-14 03:47:12