  We conducted a benchmarking analysis of the semi-regular pulsator and red
supergiant $\alpha$ Ori. In its dimming episode last 2020, our observational
results include the binned measurements from the space-based telescope SMEI
collated. We report a long secondary period of $P_{\text{LSP}}$ = 2350 $\pm$ 10
d and a fundamental pulse of $P_0$ = 415 d $\pm$ 30 d for the interest.
Meanwhile, we also detected the first overtone component of $P_1$ = 185 d which
supports the current literature's standing for this newly acquired pulse. At
$~$2.20 $\pm$ 0.10 $\mu$m, we acquired Near-Infrared $K$-band photometric
measurements from several catalogues and surveys in accordance of the
calibration. Our assigned inherent color plays at the middle of the extremes
from the existing literature. Likewise, we attained a weighted excess color
index of $E_{(B-V)}$ = 0.340 and using a $K$-extinction factor of $R_K$ = 0.382
yields an extinction of $A_K$ = 0.130. By subtracting extinction to all
$K$-band photometry, using the linearity, and newly derived distance from
previous literatures, our effort results to a $\log(L/L_\odot) = 5.00 \pm
0.15_{(-0.45)}^{(+0.48)}$ for $\alpha$ Ori. In turn, this allowed us to conduct
the benchmarking scheme alongside the data from existing reports that are
stitched together using Period-Luminosity Relationship. This results to a
best-fit of $\log(L/L_\odot) = 7.26 \pm 0.10 \times \log P + (-14.10 \pm 0.25)$
and reveals that $\alpha$ Ori can be situated in the lower bound 18 $M_\odot$
regime caused by current pulsation trends.
