Atmospheric composition of the temperate super-Jupiter Epsilon Indi Ab revealed

Epsilon Indi Ab is a temperate super-Jupiter orbiting the star Epsilon Indi A. As one of the closest and coldest directly imaged exoplanets, it serves as a bridge for comparing the atmospheric properties of hot gas giants found around other stars with the cooler giants of our own solar system. Infrared observations have now successfully mapped the chemical makeup of its atmosphere despite the challenging light interference from its host star.

The findings reveal a distinct chemical signature within the atmosphere of Epsilon Indi Ab. By analyzing light across infrared wavelengths, researchers identified several key molecules present in the planet's gaseous envelope. These chemical markers provide insight into the atmospheric conditions of this cold, massive world.

To isolate the weak planetary signal from the intense glare of the host star, advanced data processing was required. By applying high-pass filtering and cross-correlation techniques using specialized atmospheric models, the planetary light was successfully extracted, allowing for the precise identification of various chemical components.

The research demonstrates that even when a bright host star severely contaminates direct observations, infrared spectroscopy can effectively determine the composition of distant planetary atmospheres. This success paves the way for deeper investigations into the diversity of gas giants across the galaxy.

Key findings
- Robust detection of ammonia in the atmosphere of Epsilon Indi Ab.
- Presence of water and methane confirmed through infrared data.
- Marginal detection of carbon dioxide recorded.
- High-pass filtering and cross-correlation proved effective for isolating planetary signals near bright stars.

Scientific study

Molecular mapping of an exoplanet with JWST: NH3 detection in the temperate super-Jupiter Epsilon Indi Ab (external link)