News Release

New Durham University study reveals mystery of decaying exoplanet orbits

EMBARGOED UNTIL 00.01 BST on Monday 29 April 2024

Peer-Reviewed Publication

Durham University

-With images-

A new study led by researchers at Durham University has uncovered a novel mechanism that could solve a long-standing mystery about decaying planetary orbits around stars like our Sun.

The study, published in The Astrophysical Journal Letters, proposes that stellar magnetic fields play a crucial role in dissipating the gravitational tides responsible for the orbital decay of ‘hot Jupiter’ exoplanets.

Hot Jupiters are massive, gaseous planets similar to Jupiter that orbit extraordinarily close to their parent stars, taking only a few days to complete one orbit.

This close proximity subjects both the planet and star to powerful gravitational tides that transfer orbital energy, causing the planets to slowly spiral inwards over billions of years until they are eventually consumed.

Current tidal theories cannot fully explain the observation of orbital decay in the system WASP-12b, a hot Jupiter whose decaying orbit will send it into its host star WASP-12 in a few million years.

According to the research team, which included scientists from University of Leeds and Northwestern University alongside Durham, strong magnetic fields within certain sun-like stars can dissipate the gravitational tides from hot Jupiter planets very efficiently.

The tides create inward waves inside the stars. When these waves encounter the magnetic fields, they get converted into different types of magnetic waves that travel outwards and eventually disappear.

Reflecting on the research findings, lead author of the study Dr Craig Duguid of Durham University, said: “This new mechanism has wide reaching implications for the survival of short period planets and particularly hot Jupiters.

“It opens a new avenue of tidal research and will help guide observational astronomers in finding promising targets to observe orbital decay.

“It is also quite exciting that this new mechanism could be observationally tested within our lifetime.”

The study findings suggest certain nearby stars may be good targets to search for additional hot Jupiter planets on decaying orbits.

If found, they could provide more evidence about how magnetic fields impact the tides from these alien worlds.

The research could also reveal where the dissipated tidal energy goes within the star's interior.


Media Information

Dr Craig Duguid from Durham University is available for interview and can be contacted on

Alternatively, please contact Durham University Communications Office for interview requests on or +44 (0)191 334 8623.


‘An efficient tidal dissipation mechanism via stellar magnetic fields’, (2024), C Duguid, N De Vries, D Lecoanet and A Barker, The Astrophysical Journal Letters.  

An embargoed copy of the paper is available from Durham University Communications Office. Please email to request a copy.


Associated images are available via the following link:

Caption: Artist’s concept of the exoplanet WASP-12b.

Credit: NASA/ESA/G. Bacon

About University of Leeds 

The University of Leeds is one of the largest higher education institutions in the UK, with more than 39,000 students from about 140 different countries. We are renowned globally for the quality of our teaching and research.

We are a values-driven university, and we harness our expertise in research and education to help shape a better future for humanity, working through collaboration to tackle inequalities, achieve societal impact and drive change.  

The University is a member of the Russell Group of research-intensive universities, and is a major partner in the Alan Turing, Rosalind Franklin and Royce Institutes    

About Durham University

Durham University is a globally outstanding centre of teaching and research based in historic Durham City in the UK.

We are a collegiate university committed to inspiring our people to do outstanding things at Durham and in the world.

We conduct research that improves lives globally and we are ranked as a world top 100 university with an international reputation in research and education (QS World University Rankings 2024).

We are a member of the Russell Group of leading research-intensive UK universities and we are consistently ranked as a top 10 university in national league tables (Times and Sunday Times Good University Guide, Guardian University Guide and The Complete University Guide).

For more information about Durham University visit:

END OF MEDIA RELEASE – issued by Durham University Communications Office.

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