Are strongly magnetized degenerate stars cooling by axion emission?

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We considered recently as a new axion production mechanism the process e- → e- +a in a strong magnetic field B. Requiring that for a strongly magnetized neutron star the axion luminosity is smaller than the neutrino luminosity we obtained the bound gae 10⁻¹⁰ for the axion electron coupling constant. This limit is considerably weaker than the bound derived earlier by Borisov and Grishina using the same method. Applying a similar argument to magnetic white dwarf stars we obtained gae 9 · 10⁻¹³ (T/10⁷)⁵/⁴ (B/10¹⁰)⁻², where T is the internal temperature of the white dwarf. Here we note that the observed lack of magnetized white dwarfs with low-temperature in the galactic disc could also be interpreted as a signature of axion emission. Moreover, we speculate that axion emission could explain why the putative galactic halo population of white dwarfs is so dim.