The thermo-chemical state of circumstellar disks determines the composition of planets that form in them, and is hence the key to understand exoplanet diversity. Yet, the temperature and chemical composition of the gas in these disks is not known, in particular the properties of the gas in the midplane inside of ∼10 au (Woitke et al. 2018, A&A 618, 57), where most of the planets form. In this project, we want to study grain charging processes in protoplanetary disks and their feedback on gas ionisation and observation of line emission by molecular ions. Based on a moment method developed in Thi et al. (2018, arXiv 1811.08663), we want to compute the size-dependent charge distribution function of grains f(a,Z) in the disk, where a is the grain radius and Z its charge, based on our state-of-the-art disk modelling software ProDiMo (Woitke et al. 2016, A&A 586, 103). In particular, we want to include the so-called tribo-electric effect, where grains undergo frictional charging when they collide with each other in a turbulent environment. In combination with dust settling, this effect is known to cause electrification of volcano plumes and, more general, lightning in the Earth atmosphere (Helling et al. 2016, Survey in Geophysics 37, 705). It is hence the aim of this project to find out in how far this mechanism also applies to protoplanetary disks, and could change the chemical composition and ionisation in disks.

This project is part of the Marie Sklodowska-Curie Innovative Training Network (ITN) CHAMELEON “Virtual Laboratories for Exoplanets and Planet Forming Disks”. The ITN combines the expertise of eight European research institutes (Universities of St Andrews, Groningen, Copenhagen, Edinburgh, Leuven and Antwerp, the Max-Planck Institute in Heidelberg and the Netherlands Institute for Space Research) to cover all relevant aspects for this complex modelling task, joining the expertise in planetary atmospheres and protoplanetary disks, including observation and interpretation. For a complete list of all open PhD positions within this training network please visit http://chameleon.wp.st-andrews.ac.uk/

The selected PhD students will be offered a fully funded PhD place at the University of St Andrews’ Centre for Exoplanet Science with training secondment for this position foreseen at the University of Copenhagen, with additional short training at the University of Groningen. The PhD student will receive a double degree from St Andrews and from Copenhagen. The funding will be commensurate to the standard scale for PhD students in according to the Marie-Curie funding rules. The successful PhD applicants will have to register at, and comply with, the regulations of the St Leonard’s Postgraduate College at the University of St Andrews and the rules from the University of Copenhagen. The successful PhD applicants will follow a doctoral programme including personal training in management, science communication, and teaching.

We seek an excellent student with a strong background in physics or astrophysics. Successful candidates must hold a Masters degree or equivalent by the starting date of the position. Previous research experience on planet forming disks and/or astrochemistry, and a track record of team work/mobility will be important criteria for the selection. This is a computational project: some prior knowledge of coding would be useful (e.g., Python and Fortran). Note that the general eligibility and mobility rules of Marie Sklodowka-Curie Actions apply.

Eligibility: CHAMELEON PhD studentships are open to people of any nationality. However, the Marie S. Curie Actions have two strict eligibility criteria for applicants to these positions:

1. EARLY STAGE: The applicant must be within the first four years (full-time equivalent research experience) of her/his research career (starting from the moment you obtain a degree that makes you eligible to study for a PhD) and not have a doctoral degree. Adjustments can be made for career breaks.

2. MOBILITY: The applicant must not have resided or carried out her/his main activity (e.g. work, studies) in the country where she/he has been recruited for more than 12 months in the three years immediately before the recruitment date (this is the day on which you start your PhD).

Further information about eligibility criteria, the application process and the online application form are available at: http://chameleon.wp.st-andrews.ac.uk/recruitment.

Deadline: 3 February 2020

Submit applications to: https://www.st andrews.ac.uk/physics/prosp_pg/index.php

For the first 3 years of employment, as Marie Sklodowska-Curie Fellows, you will receive generous benefits, including a fixed salary/living allowance and mobility/ family allowance HYPERLINK "https://ec.europa.eu/research/participants/data/ref/h2020/wp/2018-

School of Physics & Astromomy

Fixed Term: 3.5 years, fully funded

Start Date: Autumn 2020 PhD Entry