Discovering exoplanets around compositionally-diverse stars across the Milky Way by mitigating stellar signals

We invite applications from outstanding and highly motivated students for the Warwick Prize Scholarships in Astrophysics. The successful applicant will work with Dr Thomas Wilson within the Astronomy and Astrophysics group in the Department of Physics at the University of Warwick.

This project will investigate stellar activity in exoplanet observations to discover and study the atmospheres and interiors of Earth-like exoplanets orbiting compositionally-diverse stars

Terrestrial exoplanets are formed out of pebbles within the protoplanetary disk. These building blocks are mainly iron and silicates, with heavier components sinking to form metallic cores and lighter ones rising to produce planet mantles. As protoplanetary disks and stars are built from the same material, any planets are therefore also predicted to be compositionally linked to the host star. This means that exoplanets orbiting compositionally-diverse stars, i.e. iron-poor or silicate-rich, should have different interiors that would affect everything from volcanism to magnetic fields to atmospheres, and change the habitability of Earth-like planets. Using the TESS and CHEOPS space telescopes and the HARPS-N instrument we can discover and study the interiors of exoplanets orbiting compositionally-diverse stars by determining their radii and masses.

Exoplanet radial velocity (RV) instruments have routinely measured planetary masses over the last few decades with a main goal to discover and study an Earth-mass planet. However, in recent years progress towards lower-mass planets has slowed due to stellar processes mimicking planet signals making orbiting bodies harder to detect. These processes affect both exoplanet RV and transit photometry data, however these have mainly being studied in HARPS-N, Kepler, TESS, and CHEOPS observations separately limiting the ability to find low-mass exoplanets. Recently, a ground-breaking technique has been developed to combine exoplanet data from different RV and transit sources to remove stellar activity and discover smaller exoplanets. This promising method will likely become crucial when measuring the radii and masses of Earth-twins discovered by the PLATO space-telescope set to be launched in 2026. Use this new tool and other methods on observational exoplanet data from the TESS, CHEOPS, and HARPS-N facilities we can measure and mitigate stellar signals and confidently discover orbiting terrestrial exoplanets.

The student will have the flexibility to pursue the above research areas during their PhD. This project will discover exoplanets around iron-poor stars with the TESS spacecraft and by analysing exoplanet transit photometry and radial velocity data from the CHEOPS and HARPS-N instruments understand the interior structures and atmospheric escape results of these planets. This project will develop new techniques and frameworks using Gaussian Process methods to fit exoplanet radial velocity and transit photometry data and confidently detect and measure the masses of exoplanets.

Warwick is an internationally recognised centre of research excellence. Our group takes leading roles in many major ground and space-based projects, including the Gravitational-wave Optical Transient Observer (GOTO), Next Generation Transit Survey (NGTS), PLAnetary Transits and Oscillations of stars (PLATO) telescope, Sloan Digital Sky Survey (SDSS), WHT Enhanced Area Velocity Explorer (WEAVE) spectrograph, 4-metre Multi-Object Spectrograph Telescope (4MOST), Dark Energy Spectroscopic Instrument (DESI), and CHaracterising ExOPlanet Satellite (CHEOPS).

The Astronomy & Astrophysics group is part of the Physics Department at Warwick; both the department and the university hold Athena SWAN Silver awards, a national initiative to promote gender equality for all staff and students. The Physics Department is also a Juno Champion, which is an award from the Institute of Physics to recognise our efforts to address the under-representation of women in university physics and to encourage better practice for all. The Astronomy & Astrophysics group also hosts monthly equitea forums to break down barriers faced by all under-represented groups in science.

More details on PhD positions with the Astronomy and Astrophysics group at Warwick are available here.

Start Date: October 2024

Funding Duration: 3.5-4.0 years

Applications due by: 9 January 2024

Eligibility

You must have or expect a First or Upper second class MSci, MPhys or equivalent degree in Physics or a closely related discipline. Holders of BSc honours degrees are eligible but successful BSc applicants typically have substantial additional research experience. International equivalents are detailed here.

For students whose first language is not English, we normally require a score of 6.5 in IELTS or equivalent. If your previous degree was taught in an English-speaking country this requirement may be waived. See this page.

The award is available to home and international applicants.

How To Apply

You must apply through the University’s online application system and follow the instructions. Use course code P-F3P0, and see our Frequently Asked Questions. Make sure to state an interest in the Astronomy and Astrophysics group. Please state ‘Warwick Prize Scholarships’ as the funding option. We encourage applicants to express interest in more than one available PhD project.

 Funding Notes

The project will provide a full UK-standard annual tax-free stipend of £19,237 rising with inflation, plus allocations for travel and computing.