58³Ô¹Ï

Dr Ryan MacDonald

Lecturer in Extrasolar Planets

Phone

+44 (0)1334 46 3175

Email

Ryan.MacDonald@st-andrews.ac.uk

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Biography

Dr Ryan MacDonald is an expert in the atmospheres of planets orbiting other stars (exoplanets). He joined the School in 2025, after completing a NASA Sagan Fellowship at the University of Michigan and serving as a Research Associate at Cornell University's Carl Sagan Institute. Dr MacDonald completed his PhD in 2019 at the University of Cambridge, where he developed new Bayesian techniques to characterise exoplanet atmospheres.

Research areas

Exoplanet science raises some of the most profound questions in modern astronomy. What is the nature of worlds around other stars? Do the rocky planets in our galaxy resemble Earth, or is our blue marble an anomaly? Are we alone in the Universe?

Dr MacDonald's research at 58³Ô¹Ï combines cutting-edge telescope observations—such as the James Webb Space Telescope—with state-of-the-art theoretical modelling to decode exoplanet atmospheres. He is the lead developer of the POSEIDON atmospheric retrieval code, which has enabled numerous breakthroughs in exoplanet science, including:

• The first detection of titanium oxide in an exoplanet atmosphere ()—.
• The first detection of mineral clouds in a transiting exoplanet atmospheres ()—.
• The first discovery of a 'steam world' ()—.

Dr MacDonald leads several observing programs using JWST to characterise exoplanet atmospheres, whilst also being a core member of many international collaborations with access to ground- and space-based exoplanet spectra.

Students at 58³Ô¹Ï working with Dr MacDonald will therefore be directly involved with research at the frontier of exoplanetary science.

PhD supervision

• StenÌýVermeiren

Selected publications

• Open access
  MacDonald, R. J. & Lewis, N. K., 10 Apr 2022, In: The Astrophysical Journal. 929, 1, 32 p., 20.

  Research output: Contribution to journal › Article › peer-review

• Kaltenegger, L., MacDonald, R. J., Kozakis, T., Lewis, N. K., Mamajek, E. E., McDowell, J. C. & Vanderburg, A., 20 Sept 2020, In: The Astrophysical Journal Letters. 901, 1, 9 p., L1.

  Research output: Contribution to journal › Article › peer-review

• Open access
  Grant, D., Lewis, N. K., Wakeford, H. R., Batalha, N. E., Glidden, A., Goyal, J., Mullens, E., MacDonald, R. J., May, E. M., Seager, S., Stevenson, K. B., Valenti, J. A., Visscher, C., Alderson, L., Allen, N. H., Cañas, C. I., Colón, K., Clampin, M., Espinoza, N. & Gressier, A. & 22 others, Huang, J., Lin, Z., Long, D., Louie, D. R., Peña-Guerrero, M., Ranjan, S., Sotzen, K. S., Valentine, D., Anderson, J., Balmer, W. O., Bellini, A., Hoch, K. K. W., Kammerer, J., Libralato, M., Mountain, C. M., Perrin, M. D., Pueyo, L., Rickman, E., Rebollido, I., Sohn, S. T., van der Marel, R. P. & Watkins, L. L., 20 Oct 2023, In: Astrophysical Journal Letters. 956, 2, 15 p., L32.

  Research output: Contribution to journal › Letter › peer-review

• Sedaghati, E., Boffin, H. M. J., MacDonald, R. J., Gandhi, S., Madhusudhan, N., Gibson, N. P., Oshagh, M., Claret, A. & Rauer, H., 14 Sept 2017, In: Nature. 549, p. 238-241 18 p.

  Research output: Contribution to journal › Article › peer-review

• Open access
  May, E. M., MacDonald, R. J., Bennett, K. A., Moran, S. E., Wakeford, H. R., Peacock, S., Lustig-Yaeger, J., Highland, A. N., Stevenson, K. B., Sing, D. K., Mayorga, L. C., Batalha, N. E., Kirk, J., Lopez-Morales, M., Valenti, J. A., Alam, M. K., Alderson, L., Fu, G., Gonzalez-Quiles, J. & Lothringer, J. D. & 2 others, Rustamkulov, Z. & Sotzen, K. S., 11 Dec 2023, In: Astrophysical Journal Letters. 959, 1, 17 p., L9.

  Research output: Contribution to journal › Letter › peer-review

• MacDonald, R. J. & Madhusudhan, N., 24 May 2017, In: Monthly Notices of the Royal Astronomical Society. 469, 2, p. 1979-1996 18 p.

  Research output: Contribution to journal › Article › peer-review

• Open access
  MacDonald, R. J., 13 Jan 2023, In: Journal of Open Source Software. 8, 81, 6 p., 4873.

  Research output: Contribution to journal › Article › peer-review

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