Hubble spectroscopy of AU Mic b hampered by stellar activity

Astronomers using the Hubble Space Telescope obtained a transmission spectrum of the young exoplanet AU Mic b, but unstable scanning and strong stellar activity limited the analysis of its atmosphere. The observations were made with Hubble’s Wide Field Camera 3 covering wavelengths from 0. 8 to 1. 6 micrometres.

AU Mic b, a sub-Neptune orbiting a 20-million-year-old star, was the target of the study. Scientists found that the planet’s transmission spectrum showed only weak atmospheric signatures because stellar contamination and instrumental systematics dominated the signal. Sciencecast reported that the unstable scanning mode of the instrument further hampered the data quality. As a result, the team could place only limited constraints on the composition of the planet’s atmosphere.