Exoplanet Diversity: Atmosphere

Exoplanet Diversity: Atmosphere

Researchers have detected thousands of planets orbiting stars other than the Sun. The data show that these planets are even more varied than the planets and moons in our solar system. They range from small rocky planets a fraction of the size of Earth to large gas giants several times the size of Jupiter. Some orbit cool dwarf stars while others circle stars much hotter and more massive than the Sun. And like the objects in our solar system, they have a wide variety of compositions and structures.

Although no exoplanet is close enough to visit with a space probe, we can—under the right conditions—study an exoplanet’s atmosphere. When a planet passes in front of its star, some of the starlight is filtered through the planet’s atmosphere. We can analyze the pattern of the filtered light (a transmission spectrum) to figure out what the atmosphere is made of. The peaks in the graph above represent the amount of light blocked by the exoplanet’s atmosphere – the largest peaks represent more light being filtered out.

The transmission spectra shown here are models based on assumptions about the composition, temperature, and structure of the exoplanet’s atmosphere. As observatories like the James Webb Space Telescope continue to operate, scientists will compare their data to the models to figure out which assumptions are correct and which are not.

Quick Facts: Atmosphere