# Near-UV and optical spectroscopy of comets using the ISIS spectrograph on the WHT

## TL;DR

This study uses the ISIS spectrograph on the WHT to analyze the spectral composition of eleven comets, detecting multiple molecular emissions and estimating their production rates, contributing to understanding cometary compositions.

## Contribution

First long-slit cometary spectroscopy analysis with ISIS on WHT, detecting multiple species and applying Haser modeling for production rates.

## Key findings

- Detected OH, NH, CN, C3, C2, NH2, [OI] emissions in comet spectra.
- Derived molecular production rates consistent with previous studies.
- Provided new spectral data for eleven comets observed in 2016.

## Abstract

We present an analysis of long-slit cometary spectroscopy using the dual-arm ISIS spectrograph on the 4.2 m WHT. Eleven comets were observed over two nights in 2016 March and we detected the OH (0-0) emission band at 3085 {\AA} in the spectra of five of these comets. Emission bands of the species NH, CN, C$_{3}$, C$_{2}$, NH$_{2}$ and [OI] were also detected. We used Haser modelling to determine molecular production rates and abundance ratios for the observed species. We found that our average abundances relative to OH and CN were generally consistent with those measured in previous studies.