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Tracking the spectral evolution of transiently accreting neutron starsbetween outburst and quiescence probes relatively poorly understood accretionregimes. Such studies are challenging because they require frequent monitoringof sources with luminosities below the thresholds of current all-sky X-raymonitors. We present the analysis of over 30 observations of the neutron starlow-mass X-ray binary SAX J1750.8-2900 taken across four years with the X-raytelescope aboard Swift. We find spectral softening with decreasing luminosityboth on long ($\sim$1 year) and short ($\sim$days to week) timescales. As theluminosity decreases from $4\times10^{36}$ erg s$^{-1}$ to $ \sim1\times10^{35}$ erg s$^{-1}$ (0.5-10 keV), the power law photon index increases from from 1.4to 2.9. Although not statistically required, our spectral fits allow anadditional soft component that displays a decreasing temperature as theluminosity decreases from $4 \times 10^{36} $ to $6 \times 10^{34}$ ergs$^{-1}$. Spectral softening exhibited by SAX J1750.8-2900 is consistent bothwith accretion emission whose spectral shape steepens with decreasingluminosity and also with being dominated by a changing soft component, possiblyassociated with accretion onto the neutron star surface, as the luminositydeclines.

Spectral Softening Between Outburst and Quiescence In The Neutron Star Low-Mass X-Ray Binary SAX J1750.8-2900