Comets and asteroids are the remnants of the planet formation process within our planetary system. The recent discoveries from the ESA Rosetta mission, together with the NASA OSIRIS-REx & JAXA Hayabusa-2 asteroid sample-return missions to primitive asteroids, provide detailed information on individual objects. But it is important to combine these results with the thousands of small icy objects known to exist and put together a picture of the compositional variation in the outer Solar system, and how these objects evolve. Over 3000 comets have been identified orbiting the Sun to date, recognised by their mass-loss due to the sublimation of near-surface ices. Our aim is to better understand comets, either by accurate measurement of their compositions, and by monitoring their mass-loss rates as they approach and recede from the Sun.
The project will involve measuring the activity, mass-loss rates and compositions of active comets in our Solar system. It will involve the analysis of one of the following datasets:
Cometary Spectrophotometry. We obtained large amounts of optical spectroscopy of the Jupiter-Family Comet 46P/ Wirtanen during its close approach to Earth in 2018/2019, plus snapshots of a set of Oort-Cloud Comets in 2019. These data will be analysed by the student to derive gas sublimation rates and atmospheric compositions of these comets, to compare with previous results and search for compositional trends with distance and age. In 2022/23 we will begin obtaining data with the new SOXS instrument at ESO, extending these analyses into the near-infrared.
Cometary Photometry. We are partners in the ATLAS project, which every month obtains large amounts of data on visible comets at a cadence of up to once per 2 days. Indeed, ATLAS has discovered over 50 new comets over the past 4 years of operations. Data for a selection of Jupiter-Family and Oort-Cloud Comets will be remeasured and analysed to obtain the mass-loss rates as a function of heliocentric distance, giving better estimates for the lifetimes of comets and allowing a search for cometary outbursts. This study will inform future cometary studies using the Vera C. Rubin Observatory LSST from 2023.
For additional information or questions please contact Prof. Alan Fitzsimmons (firstname.lastname@example.org). This project will have scientific connections to other members in the Solar System group, including Dr. Meg Schwamb.