Multiplicity Statistics of Stars in the Sagittarius Dwarf Spheroidal
  Galaxy: Comparison to the Milky Way
  We use time-resolved spectra from the Apache Point Observatory Galactic
Evolution Experiment (APOGEE) to examine the distribution of radial velocity
(RV) variations in 249 stars identified as members of the Sagittarius (Sgr)
dwarf spheroidal (dSph) galaxy by Hayes et al (2020). We select Milky Way (MW)
stars that have stellar parameters ($log(g)$, $T_{eff}$, and $[Fe/H]$) similar
to those of the Sagittarius members by means of a k-d tree of dimension 3. We
find that the shape of the distribution of RV shifts in Sgr dSph stars is
similar to that measured in their MW analogs, but the total fraction of RV
variable stars in the Sgr dSph is larger by a factor of $\sim 2$. After ruling
out other explanations for this difference, we conclude that the fraction of
close binaries in the Sgr dSph is intrinsically higher than in the MW. We
discuss the implications of this result for the physical processes leading to
the formation of close binaries in dwarf spheroidal and spiral galaxies.
