Atmospheric analysis of giant planet TOI-3235 b reveals challenges with red dwarf stars

Star system: TOI 3235 | Distance from the Sun: 237 light years

The giant planet TOI-3235 b, which has a mass about two-thirds that of Jupiter and a temperature of 604 Kelvin, orbits a small Red dwarf star. Studying the atmospheres of such massive planets around small, cool stars is important for understanding how they formed, as current theories suggest they should be rare. However, light from the host star often interferes with these observations, creating signals that can be mistaken for atmospheric features.

Researchers analyzed transmission spectra—the light filtered through a planet's atmosphere as it passes in front of its star—collected by the James Webb Space Telescope. They tested various mathematical models to separate the planet's actual atmospheric signal from the noise created by the star itself.

When the star's interference was modeled strictly, the results suggested unusual levels of methane, carbon monoxide, and carbon dioxide. However, further analysis showed that these findings were highly dependent on the specific model used, as residual star-related noise remained in the data, preventing a definitive conclusion about the planet's chemical composition.

Future observations of the planet passing behind its star, known as an eclipse, may resolve these ambiguities. If scientists can measure heat emissions directly from the planet, it would provide a clear way to verify its composition and confirm whether the observed signals were truly from the atmosphere or just stellar interference.

Key findings
- TOI-3235 b is a giant planet with 0.665 times the mass of Jupiter orbiting a Red dwarf.
- Analyzing the planet's atmosphere is currently hindered by significant interference from the host star's light.
- Previous estimates of methane and carbon dioxide levels are model-dependent and not yet definitive.
- Using additional statistical methods to account for stellar noise broadens the range of possible atmospheric outcomes.
- Future eclipse observations could provide an empirical way to separate planetary signals from stellar contamination.

Scientific study

JWST Transmission Spectroscopy of TOI-3235 b: Challenges in Constraining Giant Planet Atmospheres Around M Dwarfs Amid Stellar Contamination (external link)