Dr Philip J Carter

University of Bristol


My research focuses on numerical simulations of planet formation. I am interested in collisions of planetesimals, giant impacts between protoplanets, the effects collisions can have on the compositions of growing planets, and the remnants of the early solar system found in meteorites.
I am also interested in the final fates of planetary systems, long after their host star has died and left behind a white dwarf.

Find out more here.
Image: Gemini Observatory/AURA/Lynette Cook.

About Me

I am a computational planetary scientist and astrophysicist. I carry out research related to planetary collisions and planet growth. I am a Senior Research Associate in the School of Physics at the University of Bristol.
Previously, I was a Postdoc, and then Project Scientist, in the Department of Earth and Planetary Sciences at the University of California, Davis. My scientific background is in astrophysics, having obtained my PhD in 2014 from the University of Warwick, where I carried out observational studies of ultra-compact accreting binaries.

See my CV for more details.


March 2024: Formation of super-Mercuries via giant impacts – Dou et al. (2024)
In this paper, published in MNRAS, we modelled mantle-stripping in giant impacts between rocky planets. We derived new scaling relations that predict the mass and core mass resulting from impacts and discuss the collisions needed to form Mercury-like planets with high iron core masses.

Masses and radii expected for planets that have undergone 
	              collisional stripping

August 2023: A super-massive Neptune-sized planet – Naponiello et al. (2023)
In this paper by Naponiello et al., published in Nature, we present the discovery of the ultra-dense Neptune-sized planet TOI-1853b. With a mass of 73 Earth masses and a density of 9.7 grams per cubic centimetre, TOI-1853b presents a challenge for conventional theories planet formation. Our simulations show that the initial planetary body would likely have needed to be water-rich and suffer an extreme giant impact at a speed of greater than 75 km/s in order to produce TOI-1853b as it is observed.
See also coverage from: Space.com, Phys.org.

Simulation of a giant impact that could produce TOI-1853b

April 2022: Did Earth eat its leftovers? – Carter & Stewart (2022)
In this paper, published in The Planetary Science Journal, we investigate the provenances of planetesimals 'leftover' in the inner disk in the late stages of accretion simulations.
An executable version of the paper is available on GitHub.

Provenance correlation of bodies to three most massive embryos

April 2022: Denman et al. (2022) – Atmosphere loss in oblique Super-Earth collisions
In this work by Denman et al. we modelled the loss of atmosphere in oblique collisions between super-Earth sized planets. We show that oblique collisions are less efficient at atmosphere removal than head-on collisions. We found that a single collision cannot remove all the atmosphere without also removing a significant fraction of the mantle.
Read the paper in MNRAS.

Oblique Super-Earth collisions

January 2022: Congratulations Dr Denman!
Dr Thomas Denman passed his viva in November and has now been awarded his PhD!

You can read about Dr Denman's work on collisions of Super-Earths at Explore Bristol Research.

News archive

Movie of the week

Rocky protoplanet accretion in a calm disc

Studying the moon
Image: STS.