An international team of astronomers has studied the ultra-hot Jupiter HAT-P-70 b and measured the wind speed in its atmosphere. It is 18,000 kilometers per hour.
Hot Jupiters are gas giants whose orbits pass at a very short distance from their parent stars. The atmospheres of such worlds are heated to extreme temperatures. In doing so, they are in a tidal grip, being always turned to their star on the same side.
HAT-P-70 b represents one of the most extreme hot Jupiters known to us. The exoplanet orbits around a luminary of spectral class A. It is so close to the star that it has an orbital period of 2.7 Earth days and a temperature of about 2,300°C. HAT-P-70 b is also a very “chubby” exoplanet: its radius is almost twice that of Jupiter.
To peer into the atmosphere of HAT-P-70 b, the researchers used the new GHOST spectrograph on the Gemini South telescope. It was able to detect signatures of ionized calcium, a gaseous and high-energy form of calcium that can only exist under incredibly intense heating conditions. Astronomers have found that the calcium signal propagates tens of thousands of kilometers into the upper atmosphere. But more importantly, GHOST’s incredible sensitivity allowed them to track how calcium uptake changes from the morning to the evening side of the planet.
Based on these observations, the team determined that HAT-P-70 b has powerful winds blowing from the scorching day side to the cooler night side at speeds of up to 18,000 kilometers per hour. In addition, the GHOST data helped refine the exoplanet’s mass, showing that it is likely much lighter than previously thought. This is an important parameter for future comparisons of the atmospheres of super-hot Jupiters.
Earlier we reported on the fact that astronomers questioned the detection of signs of life on the planet K2-18b.
According to NOIRLab
