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Determine the actual mass of Proxima Centauri b

Determine the actual mass of Proxima Centauri b, which remains unknown because the planet is non-transiting and only a lower limit Mp sin(i) has been measured via radial velocity observations.

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Background

Proxima Centauri b is a non-transiting exoplanet, so its orbital inclination is not directly measured. As a result, radial velocity observations provide only Mp sin(i), a lower limit on the planet’s mass. In this paper, the authors assume an actual mass of 1.4 Earth masses to maintain consistency with prior GCM work, acknowledging that the true mass is not currently known.

The actual mass is a fundamental parameter that influences derived quantities such as surface gravity and can affect simulated atmospheric circulation and climate dynamics. Constraining the true mass would refine model inputs and improve assessments of climate, habitability, and observational predictions for Earth-like exoplanets around M-dwarf stars.

References

Since Proxima Centauri b is non-transiting, we only have a lower limit on its mass from the detection by the radial velocity method of Mp sin(i) =1.07 ± 0.06. Me (Anglada-Escudé et al., 2016; Faria et al., 2022), where i is the orbital inclination. Given the unknown actual mass of Proxima Centauri b and to ensure consistency with previous GCM simulations, we follow Turbet et al. (2016) and assume an actual planet mass of 1.4. Me.

— The impact of Ozone on Earth-like exoplanet climate dynamics: the case of Proxima Centauri b (2404.17972 - Luca et al., 27 Apr 2024) in Section 2.1 (Methods: Coupled climate-chemistry model)