  We describe the discovery of a solar neighborhood (d=468 pc) binary system
with a main-sequence sunlike star and a massive non-interacting black hole
candidate. The spectral energy distribution (SED) of the visible star is
described by a single stellar model. We derive stellar parameters from a high
signal-to-noise Magellan/MIKE spectrum, classifying the star as a main-sequence
star with $T_{\rm eff} = 5972 \rm K$, $\log{g} = 4.54$, and $M = 0.91$ \msun.
The spectrum shows no indication of a second luminous component. To determine
the spectroscopic orbit of the binary, we measured radial velocities of this
system with the Automated Planet Finder, Magellan, and Keck over four months.
We show that the velocity data are consistent with the \textit{Gaia}
astrometric orbit and provide independent evidence for a massive dark
companion. From a combined fit of our spectroscopic data and the astrometry, we
derive a companion mass of $11.39^{+1.51}_{-1.31}$\msun. We conclude that this
binary system harbors a massive black hole on an eccentric $(e =0.46 \pm
0.02)$, $185.4 \pm 0.1$ d orbit. These conclusions are independent of
\cite{ElBadry2022Disc}, who recently reported the discovery of the same system.
A joint fit to all available data (including \cite{ElBadry2022Disc}'s) yields a
comparable period solution, but a lower companion mass of $9.32^{+0.22}_{-0.21}
M_{\odot}$. Radial velocity fits to all available data produce a unimodal
solution for the period that is not possible with either data set alone. The
combination of both data sets yields the most accurate orbit currently
available.
