Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets

摘要: Extrasolar satellites are generally too small to be detected by nominal searches. By analogy the most active body in Solar System, Io, we describe how sodium (Na I) and potassium (K $\textit{gas}$ could a signature of geological activity venting from an otherwise hidden exo-Io. Analyzing $\sim$ dozen close-in gas giants hosting robust alkaline detections, show that Io-sized satellite can stable against orbital decay below planetary tidal $\mathcal{Q}_p \lesssim 10^{11}$. This energy is focused into driving $\sim 10^{5 \pm 2}$ higher mass loss rate than Io's supply Jupiter's Na exosphere, based on simple atmospheric estimates. The remarkable consequence several exo-Io column densities average $\textit{more sufficient}$ provide 10$^{10 1}$ cm$^{-2}$ required equivalent width exoplanet transmission spectra. Furthermore, benchmark observations both extended ($\sim 1000$ R$_J$) exosphere atmosphere spectroscopy yield similar purely exogenic nature. As proof concept, fit "high-altitude" at WASP 49-b with ionization-limited cloud observed profile about Io. Moving forward, strongly encourage time-dependent ingress egress monitoring along spectroscopic searches for other volcanic volatiles.