[PPS01-P07] Detectability of water plumes on icy moons with Earth-orbiting UV telescope
The EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) spectrometer onboard the Hisaki satellite has conducted long term monitoring of ultraviolet emissions (52.0-148.0 nm) from the Io plasma torus and Jupiter’s aurora since 2013. We also observed OI 130.4 nm around Jupiter moon Io’s orbit, and analyzed spatial distribution and temporal variations of oxygen atoms in Io torus. However, the spatial resolution of Hisaki/EXCEED is too rough (~17”) to resolve Io and Icy moon’s disk (for example, Europa’s diameter is ~1.0”). One of the main goal of post Hisaki UV satellite is to observe icy moon’s atmosphere continuously with high resolution and confine conditions under which plume eruptions occur.
We calculated the OI 130.4 nm and HI 121.6 nm counts of Europa plume (signal) and atmosphere, solar reflection, geocorona and interplanetary medium (noise), and estimated the mirror diameters, which can meet the demand that the signal to noise ratio is over 3 with integration time of 10 hours and spatial resolution of ~0.2 arcsec. Requested mirror diameters are ~140 cm when the altitude of the satellite is 1000 km, and ~100 cm when the altitude is 30,000 km.