Topic: Space

Astronomers used James Webb Space Telescope to study an exoplanet called WASP-121 b. They found that the planet's dawn and dusk regions have different temperatures and atmospheres.

The James Webb Space Telescope (JWST) has helped scientists uncover secrets about a distant alien world, known as WASP-121 b. This exoplanet is an ultra-hot gas giant that orbits its star very closely. As it rotates, the planet's day side faces the star while the night side remains in perpetual darkness.

The JWST team discovered striking differences between the dawn and dusk regions of WASP-121 b. These areas are called terminators, marking the transition from the permanent day side to the permanent night side. The findings confirm predictions that had previously existed only in theoretical models.

By analyzing how infrared starlight passes through the planet's atmosphere as it crosses in front of its host star, researchers found an uneven pattern of absorption. This asymmetry is best explained by differences in temperature and chemistry between the morning and evening sides of the planet.

The observations show that the evening terminator absorbs more light than the morning terminator. This matches current ideas about powerful atmospheric winds that transport heat from the intensely hot day side toward the cooler night side. The data collected with JWST's NIRSpec instrument also revealed a stronger carbon monoxide (CO) signal towards the end of the transit.

Researchers believe this change is caused by temperature effects rather than an actual increase in carbon monoxide abundance. Water (H2O) told a different story, suggesting that water molecules become less abundant in the hotter atmospheric regions.

The findings provide additional evidence that hot winds are warming the evening terminator.

Why It Matters

This discovery helps us better understand how planets outside our solar system work. It also shows how powerful telescopes like JWST can help us learn more about these distant worlds, which might one day be home to life.

Key Facts

• The James Webb Space Telescope (JWST) was used to study the exoplanet WASP-121 b.
• WASP-121 b is an ultra-hot gas giant that orbits its star very closely.
• The planet's dawn and dusk regions have different temperatures and atmospheres.
• The evening terminator absorbs more light than the morning terminator due to atmospheric winds.
• Carbon monoxide (CO) signals were stronger towards the end of the transit.

Key Terms

Terminators

Boundary zones marking the transition from a planet's day side to its night side.

Implications

This discovery helps us better understand how planets outside our solar system work. It also shows how powerful telescopes like JWST can help us learn more about these distant worlds, which might one day be home to life.