系外行星WASP-43b的温度分布

2024年5月3日

Temperatures on Exoplanet WASP-43b
Illustration Credit: NASA, ESA, CSA, Ralf Crawford (STScI)
Science: Taylor Bell (BAERI), Joanna Barstow (The Open University), Michael Roman (University of Leicester)

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.

Tomorrow’s picture: a new hope

系外行星WASP-43b的温度分布
图示提供: NASA, ESA, CSA, Ralf Crawford (STScI)
科学: Taylor Bell (BAERI), Joanna Barstow (The Open University), Michael Roman (University of Leicester)

说明: 距离地球仅280光年、受到潮汐锁定的木星级系外行星WASP-43b，每0.8个地球日绕行母星一圈。换算下来，它和娇小低温母星的间距大约只有200万公里，不到水星轨道半径的1/25。也因此，韦伯太空望远镜的中红外仪指出，它面朝母星的永昼面之温度将近有摄氏1400度。而如同这颗热系外行星的轨道图所示，韦伯望远镜的量测也指出，永夜面的温度保持在摄氏500度以上。这显示强劲的环赤道风，不断把白昼面的大气带到夜面，让该处的大气难以冷却下来。系外行星WASP-43b现在的正式命名为”星盘”，而其K型母星则名为”圭表”。韦伯的红外光谱侦测到星盘的白昼面和夜面有水气，因此提供了此系外行星有云层覆盖的讯息。（Astrolábos 星盘； Gnomon 圭表）

明日的图片: a new hope