James Webb Unveils Secrets of «Silicate» Exoplanet LTT 9779 b: Bright Clouds Light Up Its West
Scientists have peered into the strange world of LTT 9779 b, dubbed an ultra-hot Neptune, using the «James Webb» Space Telescope. Observing it across a light range of 0.6 to 2.8 micrometers, they explored how this distant planet reflects light and sheds heat across its surface.
Their findings paint a vivid picture: the western half of the planet’s dayside dazzles with brilliant white clouds, boasting an albedo—or light reflectivity—of 0.79. In contrast, the eastern side dims with an albedo of just 0.41. On average, the dayside bounces back half the light it receives.
Temperature readings tell another tale. The dayside sizzles at around 1,727°C, while the nightside cools sharply, never topping 1,057°C. This steep drop hints at heat racing from day to night with remarkable speed.
Researchers chalk it up to a fierce equatorial jet—a powerful air current sweeping heat westward to eastward. As the western side cools, silicate clouds form, lending it a striking brightness and reflectivity that sets it apart.
