All posts tagged: exoplanet atmosphere

JWST finds rare planet with different atmospheric conditions at dawn and dusk

JWST finds rare planet with different atmospheric conditions at dawn and dusk

Published by Jenni Sidey

WASP-121 b is split between extremes. One side faces its star nonstop and burns at about 2,770 Kelvin. The other stays in darkness and cools to roughly 1,000 Kelvin. Now astronomers have found that even the narrow boundary zones between those halves are not alike. Using the James Webb Space Telescope, a team led by Cyril Gapp of the Max Planck Institute for Astronomy detected clear differences between the planet’s morning and evening terminators, the regions where day turns to night. The result gives researchers one of their sharpest looks yet at how temperature and chemistry shift across an exoplanet’s atmosphere. The signal appeared during transit, when WASP-121 b crossed in front of its host star. As starlight passed through the planet’s atmosphere, the gases there filtered specific infrared wavelengths. By tracking how that filtering changed over the course of the transit, the team could watch different longitudes rotate into view. “With its unprecedented observational quality, JWST gives us the most detailed glimpses into distant planets to date: By measuring how star light absorption changes …

JWST finds methane in the atmosphere of a rare temperate Saturn-sized planet

JWST finds methane in the atmosphere of a rare temperate Saturn-sized planet

Published by Jenni Sidey

TOI-199 b, a rare temperate giant planet, sits between scorching hot Jupiters and frozen gas giants, and JWST has found methane in its atmosphere. That first close look begins to fill a major gap in planetary chemistry, while raising questions. Methane is common on the cold giants of our solar system, but it has been missing from one important middle ground: giant planets warm enough to be temperate, yet not roasted by their stars. That gap has now narrowed with a close look at TOI-199 b, a Saturn-sized world more than 330 light-years away. The planet circles its star every 105 days and has an estimated temperature of about 175 degrees Fahrenheit. That is still hot by everyday standards, but far milder than the blistering “hot Jupiters” that dominate many exoplanet atmosphere studies and far warmer than Jupiter and Saturn, which sit in deep cold far from the sun. Using NASA’s James Webb Space Telescope, researchers analyzed the atmosphere of TOI-199 b and found strong evidence for methane. The result makes the planet one of …

Astronomers find thick water-ice clouds on Jupiter-like exoplanet Epsilon Indi Ab

Astronomers find thick water-ice clouds on Jupiter-like exoplanet Epsilon Indi Ab

Published by Jenni Sidey

A giant planet circling a nearby star has given astronomers a rare look at what a colder, more Jupiter-like world can be like, and the picture is already messier than many models expected. The planet, called Epsilon Indi Ab, sits far enough from its star to avoid the blistering heat seen on many giant exoplanets studied so far. That alone makes it unusual. Most worlds whose atmospheres have been examined in detail orbit much closer to their stars, which makes them easier to detect but also much hotter than Jupiter. Epsilon Indi Ab is different: cold, massive, and dim, with a temperature estimated at roughly 200 to 300 Kelvin, or about minus 70 to plus 20 degrees Celsius. That places it much closer to the kind of giant planet astronomers have long wanted to study. It is not a twin of Jupiter, but it is one of the nearest things yet to a true analogue. The new observations suggest that its atmosphere may contain thick, patchy water-ice clouds, a finding that helps explain why the …

New class of planet with a permanent magma ocean found 35 light-years away

New class of planet with a permanent magma ocean found 35 light-years away

Published by Jenni Sidey

In a distant part of our cosmos, an intriguing new world exists. This newly discovered exoplanet, identified as L 98-59 d, seems to play host to a rare type of planetary environment. While many small planets orbiting distant stars are categorized as either gas dwarfs or ocean worlds, this one has been classified as something different. L 98-59 d is roughly 1.5 times larger than Earth’s diameter. Unlike most planets of this size discovered by astronomers to date, L 98-59 d appears to be a very active and dynamic body. It likely sits atop an extremely extensive molten lava ocean, estimated to be hundreds of miles deep. The lava ocean continually supplies and removes sulfur from the atmosphere of L 98-59 d and ultimately contributes to a sulfur-rich atmosphere. Astronomers studying exoplanets typically consider two scenarios when examining small planets. The first is a gas dwarf with a hydrogen atmosphere surrounding a rocky core. The second is a water world made primarily of liquid water and ice. However, the existence of an active molten lava …