  Multiple parametric limb-darkening laws have been presented, and there are
many available sources of theoretical limb-darkening coefficients (LDCs)
calculated using stellar model atmospheres. The power-2 limb-darkening law
allows a very good representation of theoretically predicted intensity
profiles, but few LDCs are available for this law from spherically symmetric
model atmospheres. We therefore present such coefficients in this work. We
computed LDCs for the space missions \textit{Gaia}, \textit{Kepler}, TESS, and
CHEOPS and for the passbands $uvby$, $UBVRIJHK$, and SDSS $ugriz$, using the
\textsc{phoenix-cond} spherical models. We adopted two methods to characterise
the truncation point, which sets the limb of the star: the first (M1) uses the
point where the derivative d$I(r)$/d$r$ is at its maximum where I(r) is the
specific intensity as a function of the normalised radius r corresponding to
$\mu_{\rm cri}$, and the second (M2) uses the midpoint between the point
$\mu_{\rm cri}$ and the point located at $\mu_{\rm cri-1}$. The LDCs were
computed adopting the Levenberg-Marquardt least-squares minimisation method,
with a resolution of 900 equally spaced $\mu$ points, and covering 823 model
atmospheres for a solar metallicity, effective temperatures of 2300 to
12000\,K, $\log g$ values from 0.0 to 6.0, and microturbulent velocities of
2\,km\,s$^{-1}$. As our previous calculations of LDCs using spherical models
included only 100 $\mu$ points, we also updated the calculations for the
four-parameter law for the passbands listed above, and compared them with those
from the power-2 law. Comparisons between the quality of the fits provided by
the power-2 and four-parameter laws show that the latter presents a lower merit
function, $\chi^2$, than the former for both cases (M1 and M2). This is
important when choosing the best approach for a particular science goal.
