  High-Reynolds-number turbulence driven by stellar convection in main-sequence
stars generates stochastic gravitational radiation. We calculate the
wave-strain power spectral density as a function of the zero-age main-sequence
mass for an individual star and for an isotropic, universal stellar population
described by the Salpeter initial mass function and redshift-dependent
Hopkins-Beacom star formation rate. The spectrum is a broken power law, which
peaks near the turnover frequency of the largest turbulent eddies. The signal
from the Sun dominates the universal background. For the Sun, the far-zone
power spectral density peaks at $S(f_\mathrm{peak}) = 5.2 \times 10^{-52}$
Hz$^{-1}$ at frequency $f_\mathrm{peak} = 2.3 \times 10^{-7}$ Hz. However, at
low observing frequencies $f < 3 \times 10^{-4}$ Hz, the Earth lies inside the
Sun's near zone and the signal is amplified to
$S_\mathrm{near}(f_\mathrm{peak}) = 4.1 \times 10^{-27}$ Hz$^{-1}$ because the
wave strain scales more steeply with distance ($\propto d^{-5}$) in the near
zone than in the far zone ($\propto d^{-1}$). Hence the Solar signal may prove
relevant for pulsar timing arrays. Other individual sources and the universal
background fall well below the projected sensitivities of the Laser
Interferometer Space Antenna and next-generation pulsar timing arrays. Stellar
convection sets a fundamental noise floor for more sensitive stochastic
gravitational-wave experiments in the more distant future.
