Explanation:
A mere 280 light-years from Earth,
tidally locked, Jupiter-sized exoplanet WASP-43b
orbits its parent star once every 0.8 Earth days.
That puts it about 2 million kilometers
(less than 1/25th the orbital distance of Mercury)
from a small, cool sun.
Still, on a dayside always facing its parent star, temperatures
approach a torrid 2,500 degrees F as measured at
infrared wavelengths by the MIRI
instrument on board the James Webb Space Telescope.
In this illustration
of the hot exoplanet’s orbit, Webb
measurements also show nightside temperatures remain above 1,000 degrees F.
That suggests that strong equatorial
winds circulate the dayside
atmospheric gases to the nightside before they can completely cool off.
Exoplanet WASP-43b is now
formally known as
Astrolábos, and its K-type parent star has been christened Gnomon.
Webb’s infrared spectra
indicate water vapor is present on the nightside as well as
the dayside of the planet, providing information about
cloud cover on Astrolábos.
Source: https://apod.nasa.gov/apod/ap240503.html
