The Sweet-Spot for Star Formation

About the Project

CONTEXT.

Star formation is one of the most fundamental processes regulating the evolution and appearance of the Universe, with implications for many diverse areas of astronomy. Two of the key observations that any theory of star formation must explain are (i) the Initial Mass Function, i.e. the distribution of stellar masses, and in particular the fact that the most common mass is of order 0.3 MSun; and (ii) the multiplicity statistics of stars, i.e. the fact that the more massive a star is the more likely it is to have a companion, possibly even more than one companion, and also the very broad distribution of separations between the components of multiple systems. An important clue to why this is the case is the observation that the efficiency of star formation appears to increase rapidly in regions where the surface-density exceeds ~ 200 MSun pc-2.

PROJECT.

This project will use numerical magneto-hydrodynamic simulations to explore the collapse and fragmentation of prestellar cores, with masses, sizes, levels of turbulence and magnetic fields derived from observation. We will use the PHANTOM Smoothed Particle Magneto-Hydrodynamics code, with additional modules to treat the thermal and chemical processes that regulate the dynamics. In particular we will explore the consequences of the shift from molecular-line cooling to dust cooling, which occurs at the critical surface-density identified above (~ 200 MSun pc-2). We will also explore the key chemical processes that influence the collapse, in particular the basic carbon chemistry and the degree of ionisation. We will extract the statistical properties of the resulting stars (masses, binary statistics, etc.), and we will post-process the results using UCLChem, LIME and RadMC to produce line profiles, line maps and dust-continuum maps.

SKILLS.

The student will become expert in interstellar gas dynamics and magneto-hydrodynamics, modelling the associated chemical and radiative processes, and converting the results into observables. Once acquired, these skills can be applied to a range of other problems in astrophysics, and many can also be applied in other fields like meteorology.

For more information, or if there are any questions, please contact Professor Anthony Whitworth WhitworthAP@cardiff.ac.uk

The typical academic requirement is a minimum of a 2:1 physics and astronomy or a relevant discipline.

Applicants whose first language is not English are normally expected to meet the minimum University requirements (e.g. IELTS 6.5 Overall with 5.5 minimum in sub-scores) (https://www.cardiff.ac.uk/study/international/english-language-requirements)

How to apply

Applicants should apply to the Doctor of Philosophy in Physics and Astronomy.

Applicants should submit an application for postgraduate study via the Cardiff University webpages (https://www.cardiff.ac.uk/study/postgraduate/research/programmes/programme/physics-and-astronomy) including:

• your academic CV
• Your degree certificates and transcripts to date including certified translations if these are not in English
• a personal statement/covering letter
• two references, at least one of which should be academic. Your references can be emailed by the referee to physics-admissions@cardiff.ac.uk

Please note: We are do not contact referees directly for references for each applicant due to the volume of applications we receive.

In the "Research Proposal" section of your application, please specify the project title and supervisors of this project.

In the funding section, please select that you will be self-funded or include your own sponsorship or scholarship details.

Once your application is submitted, we will review it and advise you within a few weeks if you have been shortlisted for an interview.