Observations of auroras on exoplanets would provide numerous insights into
planet-star systems, including potential detections of the planetary magnetic
fields, constraints on host-star wind properties, and information on the
thermal structures of planets. Tuttavia, there have not yet been any discoveries
of auroras on exoplanets. In this paper, we focus on the search for infrared
auroral emission from the molecular ion H$_3^+$, which is common in the
atmospheres of solar system planets Jupiter, Saturn, and Uranus. Using
Keck/NIRSPEC high-resolution spectroscopy, we search for H$_3^+$ emission from
two hot Jupiters, WASP-80b and WASP-69b. We do not see any evidence of emission
in the observed spectra when cross-correlating with an H$_3^+$ spectral model
or when using an auto-correlation approach to search for any significant
features. We therefore place upper limits on the total emission of $5.32 \times
10^{18}$ W for WASP-80b and $1.64 \times 10^{19}$ W for WASP-69b. These upper
limits represent the most stringent limits to date and approach the regime of
emission suspected from theoretical models.

Questo articolo esplora i giri e le loro implicazioni.

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