Cometary science with CUBES

Abstract

The proposed CUBES spectrograph for ESO's Very Large Telescope will be an exceptionally powerful instrument for the study of comets. The gas coma of a comet contains a large number of emission features in the near-UV range covered by CUBES (305-400 nm), which are diagnostic of the composition of the ices in its nucleus and the chemistry in the coma. Production rates and relative ratios between different species reveal how much ice is present and inform models of the conditions in the early solar system. In particular, CUBES will lead to advances in detection of water from very faint comets, revealing how much ice may be hidden in the main asteroid belt, and in measuring isotopic and molecular composition ratios in a much wider range of comets than currently possible, provide constraints on their formation temperatures. CUBES will also be sensitive to emissions from gaseous metals (e.g., FeI and NiI), which have recently been identified in comets and offer an entirely new area of investigation to understand these enigmatic objects.The datasets analysed during the current study are available from the corresponding author on reasonable request.

Design of the VLT-CUBES image slicers:

“…The percentage of vignetting per slitlet was evaluated in Zemax using Geometric Image Analysis and considering the contribution of the telescope, foreoptics and image slicer. The smallest vignetting is expected for the central configurations (1,6) in both resolution cases and the largest values for the external configurations (3,4) and particularly for HR mode in which the slitlets are thinner. This is what is observed in the results.…”

“…The extra-galactic science cases include measurements of the primordial deuterium abundance, the study of missing baryonic mass in the high-redshift and the origins of the cosmic UV background. The proposed solar system and planetary science cases focus on the search for water in the asteroid belt and measurements of the N2/CO ratio in comets [6]. The extra-galactic science cases cover the study of missing baryonic mass in the high-redshift circumgalactic medium and the cosmic UV background (e.g.…”