Let us assume that Betelgeuse is about to go supernova in the next years. To what extent will this affect the dose rate of ionising radiation on ground level on Earth (in orders of magnitude)? How would it affect the dose rate if the gamma-ray burst was directed in the direction of Earth?
Thank you for this anwer. However, there is a difference of several orders of magnitude between harmful and detectable. Therefore I wonder if it will be detectable and if so, to what extent. Additionally the direction of the gamma-ray burst, which is emitted in the direction of the rotation axis of the star according to scientific articles, matters.
Hi, Oliver,
I assume you're thinking of "cosmic radiation" as in "cosmic rays", ie. accelerated protons (and other nuclei). In that case, there should be an increase in the general background flux, but it would be quite a long time in the future (like ~ 1000 years), due to how the charged particles travel through the galactic medium.
An increase in CR flux does increase the ground-level ionizing radiation flux, mostly in muons, but the change depends on the primary CR particle energy.
Davide is correct that we would expect no significant effect on life here due to a Betelgeuse supernova.
If Betelgeuse had its rotation axis pointed at us then in principle it could produce a gamma-ray burst, which would be a much more threatening event. In that case the main threat would be in the form of atmospheric chemistry changes leading to severe ozone depletion, along with a short-lived (seconds) increase in surface radiation during the burst. As far as I know Betelgeuse is not oriented to produce a GRB from our perspective.
Here are some relevant papers:
Article Astrophysical Ionizing Radiation and Earth: A Brief Review a...
Article Superluminous supernovae: No threat from Eta Carinae
Article Terrestrial Effects Of Nearby Supernovae In The Early Pleistocene
Article Gamma-ray bursts as a threat to life on Earth
Do I understand correctly that the amount of high-energy/ionising electromagnetic radiation that is emitted by the supernova into other directions that that of the gamma-ray burst is negligible?
Yes, the gamma-ray and X-ray emission from a non-GRB supernova would be too small at ~600 ly to have a significant effect here.
It will become visible after it bursts and can be seen day and night. However, scattered gamma rays do not affect the ozone layer of the Earth. It is not harmful to us unless 100 light years are near. If it been 25 light years away, it would have destroyed about half the ozone layer and possibly the end of the world. Fortunately it's 725 light years away.