<p>I try to follow the discussion of axions since Peccei, Quinn, Wilzcek and Weinberg. What I still don't understand is how much the speculated stellar production of axions could add to the galactic dark matter budget and how much of the axions must be primordial to fit the bill. If the energy of the DM halo of the Milky Way is ≈2×10^59 kgm^2 s^(-2), about five times its baryonic matter content in terms of energy, how much can stellar axions have contributed to building up this halo without having radiated away the stars long ago?</p>

CC BY-SA 4.0
2023-02-04T16:12:48.193Z
This is funny - and a bit embarrassing. This above question was answered in detail on November 19, 2021, by Ethan Siegel with explicit reference to my name on his blog 'Starts with a Bang', see https://bigthink.com/starts-with-a-bang/axions-dark-matter/. But I only learned about this today! So, Ethan taught me therein that there is a third and only relevant way to produce enough axions out of the quantum vacuum that could make up to 100% of dark matter, authoring the suppression of CP-violation in the strong force at the moment of confinement of quarks and gluons in protons and neutrons.
Reggie Grünenberg
CC BY-SA 4.0
2023-02-04T16:14:33.247Z
The axions produced in the cores of massive enough stars could only amount to 1% of the dark matter content of the Universe. So, no danger of stars cannibalizing themselves to fill the dark matter bill.
Reggie Grünenberg
<star><dark-matter><axion>
What is the contribution of star-produced axions to the dark matter budget of the Milky Way?
Reggie Grünenberg
# What is the contribution of star-produced axions to the dark matter budget of the Milky Way?

(Asked by: username_0 on 2022-12-30)

I try to follow the discussion of axions since Peccei, Quinn, Wilzcek and Weinberg. What I still don't understand is how much the speculated stellar production of axions could add to the galactic dark matter budget and how much of the axions must be primordial to fit the bill. If the energy of the DM halo of the Milky Way is ≈2×10^59 kgm^2 s^(-2), about five times its baryonic matter content in terms of energy, how much can stellar axions have contributed to building up this halo without having radiated away the stars long ago?

**Tags:** star, dark-matter, axion
> **Comments:**
> **username_0**: This is funny - and a bit embarrassing. This above question was answered in detail on November 19, 2021, by Ethan Siegel with explicit reference to my name on his blog 'Starts with a Bang', see https://bigthink.com/starts-with-a-bang/axions-dark-matter/. But I only learned about this today! So, Ethan taught me therein that there is a third and only relevant way to produce enough axions out of the quantum vacuum that could make up to 100% of dark matter, authoring the suppression of CP-violation in the strong force at the moment of confinement of quarks and gluons in protons and neutrons.  
> **username_0**: The axions produced in the cores of massive enough stars could only amount to 1% of the dark matter content of the Universe. So, no danger of stars cannibalizing themselves to fill the dark matter bill.  

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## 0 answers

