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I took a look at Wikipedia's page for Proxima Centauri b, the exoplanet that orbits Proxima Centauri, where it is said it is expected to receive 2000 times of stellar wind pressures than on Earth.

It does not say anything about Proxima b having a magnetic field, but I found this paper where a magnetic field for the planet is predicted:

In our simulations, most Proxima b analogues develop intrinsic dynamos that last for 4 Gyr (the estimated age of the host star). If alive, the dynamo of Proxima b have a dipole moment . These results are not restricted to Proxima b but they also apply to earth-like planets having similar observed properties.

My question is if an Earth-like magnetic field, if Proxima b has one, could protect life as it does on Earth, or, conversely, habitability could not be possible due to stellar wind.

Jorge I.Zuluaga, Sebastian Bustamante (2018): "Magnetic properties of Proxima Centauri b analogues". Planetary and Space Science. Volume 152, March 2018, Pages 55-67

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    $\begingroup$ The problem here is "define life". We've only one planet to go by and there's no reason to assume differently based life cannot develop in quite different conditions. We can't even say that an atmosphere is a requirement for life. $\endgroup$
    – StephenG - Help Ukraine
    Commented May 21, 2019 at 14:02
  • $\begingroup$ Would this work better on the Worldbuilding Stack Exchange? $\endgroup$
    – Cloudy7
    Commented May 21, 2019 at 21:58

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According to Garcia-Sage et al. (2017) "On the Magnetic Protection of the Atmosphere of Proxima Centauri b", who assume that Proxima b has a magnetic field strength identical to the Earth, the situation does not look promising:

With an O+ and H+ escape at 1600 km altitude of 4.2×109 cm−2 s−1 as found for thermospheric densities of 3×T, the total mass-loss rate is 4.3×105 g s−1 over the dayside hemisphere. Using a total atmospheric mass of 5×1018 kg (Trenberth & Smith 2005) results in a loss of the entire mass of the atmosphere over 365 million years.

(T is the thermosphere temperature of the Earth)

They go on to note that Proxima would have had higher EUV and X-ray emission in the past, which would have made things worse. Ongoing outgassing of volatiles might be possible to create habitable conditions but the resultant situation would be very different from the Earth.

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