Dr Philip J Carter

University of Bristol


January 2022: Gadget2-planetary
The planetary version of the SPH code Gadget2 is now available on GitHub!


August 2020: Colliding in the shadows of giants – Carter & Stewart (2020)
In this paper, available on arXiv and published in The Planetary Science Journal, we investigate planetesimal–planetesimal collisions during the growth and migration of giant planets. Gas giant migration induces large numbers of high velocity collisions between planetesimals, many of which can cause shock-vaporization of planetesimal materials.

More animations from this paper can be found here.

June 2020: Denman et al. (2020) – Atmosphere loss in planet–planet collisions
Thomas Denman, a grad student at the University of Bristol I co-advise, had his first first-author paper published! In this work we modeled the loss of atmosphere in collisions between mini-Neptune and super-Earth sized planets. 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 or download from arXiv.

More animations can be found here.

February 2020: JGR Planets cover
Our paper was chosen for the cover of the latest issue of JGR Planets!

January 2020: Are exoplanetesimals differentiated? – Bonsor et al. (2020)
Short answer: yes. In this paper by Bonsor et al., available on arXiv and published in MNRAS, we compare calcium and iron abundances from a large sample of polluted white dwarfs with expected distributions from collisionally processed, differentiated planetesimals. We find that the data are best explained by 66–100% of white dwarfs having accreted the remains of differentiated bodies.

December 2019: The energy budgets of giant impacts – Carter et al. (2020)
In this paper, available on arXiv and soon to be published in JGR Planets, we explore the exchange of energy during giant impacts, the vaporization of the impactors' mantles, and the state of the resulting body immediately after the impact.

Animations from this paper can be found here.

April 2019: UC Davis Postdoctoral Research Symposium
I discussed giant impacts and moon formation at the UC Davis Postdoctoral Research Symposium.

December 2017: Collisional stripping of planetary crusts – Carter et al. (2018)
In this paper, published in EPSL, we explore the effects of collisions on the outer crust of planetesimals and planetary embryos. We find that crust is preferentially lost during collisions, and show that this can lead to changes in bulk composition of lithophile elements if reaccretion is inefficient.

Animations from this paper can be found here.

September 2017: Magnesium isotope evidence that accretional vapour loss shapes planetary compositions
In this paper by Hin et al., published in Nature, new measurements are presented that show Earth and other large planetary bodies have isotpically heavier magnesium compositions than primitive meteorites. We examine vapour loss from planetesimals as a consequence of collisions during accretion. Loss of significant mass of vapour from growing planetary embryos could explain the Earth's isotopically heavy Magnesium signature.
See also coverage from: The Washington Post, Space.com, The Independent.

October 2015: Compositional evolution during rocky protoplanet accretion
In this paper, published in ApJ, we explore the effects of collisional evolution on the compositions of planetesimals and embryos during the intermediate stages of planet formation. ADS link.

Animations from this paper can be found here.