Using a simple model to explore the energy balance of Proxima Centauri b Supervisor: Paul Palmer ([email protected]) 40 credit project.

Description New observations have identified an Earth-size planet orbiting in the habitable zone of the red dwarf Proxima Centauri [1], which (at a distance of only 1.3 parsecs) is Sun’s nearest stellar neighbour. The star has a radius that is 14% of the Sun with an effective temperature of 3050K. The orbiting exoplanet, Proxima b, has a mass at least 1.3 times that of Earth. It has an 11.2-day orbit and receives 65% of the energy from its star as Earth does from the Sun. Consequently, Proxima b is in the habitable zone of the star so that the planet’s equilibrium temperature can potentially sustain liquid water on its surface.

A number of numerical studies were published simultaneously to support these new observations, ranging in complexity from a simple energy balance model [2] to a global 3-D general circulation model [3]. Here, we will develop a simple energy balance model to determine the basic physical climate of the exoplanet given the stellar flux, building on [1], and to explore a range of scenarios assuming different atmospheric and surface environments.

Artist’s impression of the surface of Proxima Centauri b. The Alpha Centauri binary system can be seen in the background, to the upper right of Proxima. Taken from https://en.wikipedia.org/wiki/Proxima_Centauri_b

Required skills The energy balance model will be written in Python and shared using Jupyter. All subsequent model analysis will be completed in Python and Matplotlib. Knowledge of Python is essential.

References [1] Anglada-Escudé et al, A terrestrial planet candidate in a temperate orbit around Proxima Centauri, Nature 536, 437–440, 2016, doi:10.1038/nature19106.

[2] https://arxiv.org/abs/1608.07263.

[3] http://arxiv.org/abs/1608.06827.