Supervisory team: Professor Diego Altamirano

This project investigates thermonuclear (Type I) X-ray bursts on neutron stars through numerical simulations of flame spreading and ignition. You'll model burst dynamics, compare results with observations, and explore broader applications of the code to stellar flame propagation and exoplanetary atmospheres, developing strong computational and programming expertise.

Type I X-ray bursts, also known as thermonuclear bursts, occur on the surfaces of neutron stars in low-mass X-ray binary systems. Gas from a companion star accretes onto the neutron star, spreading across its surface to form a fresh layer of material. Under extreme gravity, this layer becomes compressed and heated until it reaches the critical temperature and density for thermonuclear ignition.

Nuclear fusion of hydrogen then begins, rapidly converting hydrogen into helium and then heavier elements. The resulting runaway burning releases enormous energy in X-rays—an outburst lasting seconds to minutes yet radiating more energy than the Sun emits in a week. These bursts provide a unique window into the extreme physical conditions on neutron star surfaces.

In this project, you'll develop and run simulations to model how the burning front spreads once ignition occurs. The results will be compared with observational data and theoretical predictions to improve our understanding of thermonuclear processes in compact stars. Beyond neutron stars, you'll explore how the computational methods developed here can be applied to other research areas, such as flame propagation in other stellar environments and atmospheric dynamics on exoplanets. You'll join the High-Energy Astrophysics Group and collaborate with leading researchers worldwide.

Entry requirements: You must have a UK 2:1 honours degree, or its international equivalent.

You must enjoy coding, have strong programming skills, and enthusiasm for applying computational methods to complex astrophysical problems.

Fees and Funding: Full scholarships include tuition fees, a tax-free stipend at the UKRI rate for up to 3.5 years (totalling £20,780 for 2025/26, rising annually). UK, EU and Horizon Europe students are eligible for scholarships. Chinese Scholarship Council funded students are eligible for fee waivers. Funding for other international applicants is very limited and highly competitive. Overseas students who have secured or are seeking external funding are welcome to apply.

For more information, please visit our postgraduate research funding pages.

How to apply:

Apply now

You need to:

choose programme type (Research), 2026/27, Faculty of Engineering and Physical Sciences
select Full time or Part time
search for programme PhD Physics (7089)
add name of the supervisor in section 2 of the application

Applications should include:

your CV (resumé)
2 academic references
degree transcripts and certificates to date
English language qualification (if applicable)

The School of Physics and Astronomy is committed to promoting equality, diversity inclusivity as demonstrated by our Athena SWAN award. We welcome all applicants regardless of their gender, ethnicity, disability, sexual orientation or age, and will give full consideration to applicants seeking flexible working patterns and those who have taken a career break.

The University has a generous maternity policy, onsite childcare facilities, and offers a range of benefits to help ensure employees’ well-being and work-life balance. The University of Southampton is committed to sustainability and has been awarded the Platinum EcoAward.

University of Southampton

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