  The search for dark matter (DM) is one of the most active and challenging
areas of current research. Possible DM candidates are ultralight fields such as
axions and weak interacting massive particles (WIMPs). Axions piled up in the
center of stars are supposed to generate matter/DM configurations with
oscillating geometries at a very rapid frequency, which is a multiple of the
axion mass $m_B$ [1,2]. Borra and Trottier recently found peculiar ultrafast
periodic spectral modulations in $236$ main sequence stars in the sample of
$2.5$ million spectra of galactic halo stars of the Sloan Digital Sky Survey
that were interpreted as optical signals from extraterrestrial civilizations,
possible candidates for the search for extraterrestrial intelligence (SETI)
program [3]. We argue, instead, that this could be the first indirect evidence
of bosonic axion-like DM fields inside main sequence stars, with a stable
radiative nucleus, where a stable DM core can be hosted. These oscillations
were not observed in earlier stellar spectral classes probably because of the
impossibility of starting a stable oscillatory regime due to the presence of
chaotic motions in their convective nuclei. The axion mass values, $(50 < m_B <
2.4 \times 10^{3})~ \mathrm{\mu eV}$, obtained from the frequency range
observed by Borra and Trottier, $(0.6077< f <0.6070$) THz, agree with the
recent theoretical results from high-temperature lattice quantum chromodynamics
[4,5].
