Sulfur-rich atmosphere of planet AF Lep b reveals history of solid accretion

Star system: AF Leporis | Distance from the Sun: 87.5 light years

AF Lep b is a young gas giant planet with a mass roughly three to four times that of Jupiter, orbiting its host star at a distance of approximately 9 astronomical units. Recent observations using the James Webb Space Telescope have allowed for a detailed look at the chemical composition of its atmosphere, providing new insights into how this massive planet formed and grew during the early stages of its solar system.

The research team analyzed high-contrast spectroscopy, which is a method of isolating the light from a planet to study its chemical signatures. By examining infrared light, they identified the presence of carbon dioxide, hydrogen sulfide, methane, carbon monoxide, and water vapor. These findings allowed them to calculate the abundances of carbon, oxygen, and sulfur, which are all significantly enriched compared to the levels found in the host star.

The high levels of sulfur detected in the atmosphere provide strong evidence that the planet underwent significant accretion of solid material while it was still forming within its disk of dust and gas. Based on these chemical signatures, researchers estimate that the planet contains approximately 56 Earth-masses of solid material. This level of metal enrichment is comparable to Jupiter and other known gas giants, suggesting a common growth pattern for massive planets regardless of their specific location.

Key findings
- Carbon, oxygen, and sulfur abundances in the atmosphere of AF Lep b are several times higher than those of its host star.
- The planet contains an estimated 56 Earth-masses of solid material.
- Chemical signatures suggest the planet formed near its current location rather than further out in the system.
- The enrichment levels of AF Lep b match those seen in other gas giants, indicating similar formation processes.

Scientific study

A Sulfur-Rich Atmosphere for the Young Jupiter Analog AF Lep b Reveals Significant Solid Accretion (external link)