The transient X-ray source SAX J1810.8-2609 was discovered on 1998 , March 10 with the Wide Field Cameras on board the BeppoSAX satellite , while observing the Galactic Bulge in the 2-28 keV energy range .
On March 11 , a strong type-I X-ray burst was detected with evidence of photospheric radius expansion .
A follow-up target of opportunity observation with the Narrow-Field Instruments ( NFI ) was performed on March 11 and 12 , for a total elapsed time of 8.51 \times 10 ^ { 4 } s. The wide band spectral data ( 0.1-200 keV ) obtained with the NFI show a remarkable hard X-ray spectrum detected up to \sim 200 keV , which can be described by a power law with photon spectral index \Gamma =1.96 \pm 0.04 , plus a soft component which is compatible with blackbody radiation of temperature kT \sim 0.5 keV .

The detection of the type-I X-ray burst is a strong indication that the compact object is a neutron star in a low mass X-ray binary system .
Assuming standard burst parameters and attributing the photospheric radius expansion to near Eddington luminosity , we estimate a distance of \sim 5 kpc .
The inferred 2-10 keV X-ray luminosity is \sim 9 \times 10 ^ { 35 } erg s ^ { -1 } at the time of the discovery .