Intro

profile I'm a third year PhD student at the University of St Andrews in the Schools of Physics and Astronomy and Earth and Environmental Sciences. My research is focusing on the effect of lighting on the atmospheric chemistry of Earth and other planets and investigating its impact on the origin of life. This includes Miller-Urey like sparking experiments and simulations of chemical processes in planetary atmospheres.

High-energy radiation in planetary atmospheres

solarwind We investigate the effect of stellar X-ray and UV (XUV) radiation, cosmic rays (CR), and stellar energetic particles (SEP, mainly protons) on the atmospheric chemistry of the hot Jupiter HD 189733b and identify key signatures of these interactions. We choose this planet because it is one of the best studied and observed exoplanets today, allowing us to optimize the model before later applications to habitable worlds. We use 3D simulations of HD 189733b’s atmosphere for the pressure-temperature profiles and XUV spectra of the host star from the MOVES collaboration. To model the chemical reactions, we use the STAND2019 network, which includes ion-neutral C/H/N/O chemistry. We study in detail the formation of the amino acid glycine and its precursors. Our results suggest that the CR and SEP influx enhances the formation of glycine, while XUV radiation leads to a depletion of glycine in the upper atmosphere. We identify ammonium (NH4+) as an important signature of CR and SEP influx, even though the degree of ionization of the atmosphere remains low. XUV radiation strongly ionizes the upper atmosphere, mainly producing H+ and He+. Ultimately, we show that high energy processes increase glycine and precursor production and thus may potentially play an important role in prebiotic chemistry. For more information please check out our paper (DOI, Arxiv).

Magma ocean evolution of the TRAPPIST-1 planets

magma Recent observations of the potentially habitable planets TRAPPIST-1 e, f, and g suggest that they possess large water mass fractions of possibly several tens of weight percent of water, even though the host star's activity should drive rapid atmospheric escape. These processes can photolyze water, generating free oxygen and possibly desiccating the planet. After the planets formed, their mantles were likely completely molten with volatiles dissolving and exsolving from the melt. To understand these planets and prepare for future observations, the magma ocean phase of these worlds must be understood. To simulate these planets, we have combined existing models of stellar evolution, atmospheric escape, tidal heating, radiogenic heating, magma-ocean cooling, planetary radiation, and water-oxygen-iron geochemistry. We present MagmOc, a versatile magma-ocean evolution model, validated against the rocky super-Earth GJ 1132b and early Earth. This model is part of the VPLanet code. We simulate the coupled magma-ocean atmospheric evolution of TRAPPIST-1 e, f, and g for a range of tidal and radiogenic heating rates, as well as initial water contents between 1 and 100 Earth oceans. We also reanalyze the structures of these planets and find they have water mass fractions of 0–0.23, 0.01–0.21, and 0.11–0.24 for planets e, f, and g, respectively. Our model does not make a strong prediction about the water and oxygen content of the atmosphere of TRAPPIST-1 e at the time of mantle solidification. In contrast, the model predicts that TRAPPIST-1 f and g would have a thick steam atmosphere with a small amount of oxygen at that stage. For all planets that we investigated, we find that only 3–5% of the initial water will be locked in the mantle after the magma ocean solidified. For more information please check out our paper (DOI, Arxiv) and our GitHub repository.

Publications

  • Raymond, S. N., et al., incl. Barth, P., 2021, An upper limit on late accretion and water delivery in the TRAPPIST-1 exoplanet system, Nature Astronomy, in press.
  • Barth, P., et al., Magma Ocean Evolution of the TRAPPIST-1 planets, Astrobiology 21, 11. DOI, Arxiv
  • Barth, P., et al. 2021, MOVES IV. Modelling the influence of stellar XUV-flux, cosmic rays, and stellar energetic particles on the atmospheric composition of the hot Jupiter HD 189733b, MNRAS, 502, 6201. DOI, Arxiv.
  • Woitke, P., et al., incl. Barth, P., 2021, Coexistence of CH4, CO2 and H2O in exoplanet atmospheres, A&A 646, A43. DOI, Arxiv.
  • Barnes, R., et al., incl. Barth, P., 2020, VPLanet: The Virtual Planet Simulator, PASP 132 024502. DOI, Arxiv.
  • Carone, L., Baeyens, R., Mollière, P., Barth, P., et al., Equatorial retrograde flow in WASP-43b elicited by deep wind jets?, MNRAS, 496, 3582. DOI, Arxiv.

You can find a full list of my publications here.

Talks

  • September 2021: AbGradCon 2021, Tokyo, Japan (online)
  • July 2021: Goldschmidt 2021, Lyon, France (online)
  • May 2021: NASA 'Quantifying Habitability' Science Working Group (online)
  • April 2021: vEGU21 (online)
  • March 2021: NoR-CEL meeting, St Andrews, UK (online)
  • November 2020: CHAMELEON Kick-off meeting, St Andrews, UK (online)
  • November 2020: Out Thinkers (LGBT+ STEM Week), St Andrews, UK (online)
  • October 2020: Scottish Exoplanet and Brown Dwarf Meeting, Edinburgh, UK (online)
  • July 2020: NOVO Nordisk Meeting, Niels Bohr Institute, Copenhagen, Denmark (online)
  • June 2020: StA-CES Summer Meeting, St Andrews, UK (online)
  • December 2019: PSF-Coffee, MPIA, Heidelberg, Germany
  • October 2019: VPL Meeting, University of Washington, Seattle, US
  • August 2019: StA-CES Summer Meeting, St Andrews, UK
  • March 2019: General Meeting SPP 1833 Habitable Earth, DFG, Cologne, Germany
  • April 2017: (G)Astro-Seminar, jDPG, Bad Kreuznach, Germany
  • January 2017: PSF-Coffee, MPIA, Heidelberg, Germany

Poster

  • September 2020: RAS Early Career Poster Exhibition 2020. Poster
  • August 2020: STEM Village Virtual Symposium 2020
  • July 2020: Exoplanet 3, Heidelberg, Germany
  • April 2020: UKEXOM, Birmingham, Germany (postponed due to COVID-19)
  • March 2020: Cloud Academy 2, Les Houches, France (postponed due to COVID-19)
  • September 2019: EPSC-DPS Joint Meeting, Geneva, Switzerland (presented by Ludmila Carone)
  • June 2019: AbSciCon, Seattle, US (presented by Rory Barnes)
  • June 2019: Star-planet interaction workshop, Ringberg, Germany (presented by Ludmila Carone)

Curriculum vitae

  • 2019 - now: PhD in Astronomy at the University of St Andrews, UK
  • 2017 - 2019: M.Sc. in Physics at the University of Heidelberg, Germany
    Thesis: Open Source and Versatile Magma Ocean Evolution Model for Terrestrial Exoplanets and its Application to the TRAPPIST-1 Planets. Max Planck Institute for Astronomy, Heidelberg
  • 2017 - 2018: Study abroad at the University of Washington, Seattle, WA, US
  • 2013 - 2017: B.Sc. in Physics at the University of Heidelberg, Germany
    Thesis: Large-Scale Circulation with Cloud Formation in Planetary Atmospheres. Max Planck Institute for Astronomy, Heidelberg

You can find my full CV here.

Contact

Patrick Barth (he/him)
Post graduate researcher
School of Physics and Astronomy
University of St Andrews
North Haugh
KY16 9SS St Andrews, UK
Email: pb94@st-andrews.ac.uk

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