  Asteroids that are targets of spacecraft missions are interesting because
they present us with an opportunity to validate ground-based spectral
observations. One such object is near-Earth asteroid (NEA) (162173) Ryugu,
which is the target of the Japanese Space Agency's (JAXA) Hayabusa2 sample
return mission. We observed Ryugu using the 3-m NASA Infrared Telescope
Facility (IRTF) on Mauna Kea, Hawaii, on July 13, 2016 to constrain the
object's surface composition, meteorite analogs, and link to other asteroids in
the main belt and NEA populations. We also modeled its photometric properties
using archival data. Using the Lommel-Seeliger model we computed the predicted
flux for Ryugu at a wide range of viewing geometries as well as albedo
quantities such as geometric albedo, phase integral, and spherical Bond albedo.
Our computed albedo quantities are consistent with results from Ishiguro et al.
(2014). Our spectral analysis has found a near-perfect match between our
spectrum of Ryugu and those of NEA (85275) 1994 LY and Mars-crossing asteroid
(316720) 1998 BE7, suggesting that their surface regoliths have similar
composition. We compared Ryugu's spectrum with that of main belt asteroid (302)
Clarissa, the largest asteroid in the Clarissa asteroid family, suggested as a
possible source of Ryugu by Campins et al. (2013). We found that the spectrum
of Clarissa shows significant differences with our spectrum of Ryugu, but it is
similar to the spectrum obtained by Moskovitz et al. (2013). The best possible
meteorite analogs for our spectrum of Ryugu are two CM2 carbonaceous
chondrites, Mighei and ALH83100.
