SIMBAD references

We have obtained spectroscopic measurements of the P_s = 1.8 ms, P_B = 6.5 hr black-widow (BW) pulsar PSR J1301+0833 as part of a program to investigate optical companions of wind-shrouded pulsars. The derived radial-velocity amplitude (259±4 km s^–1) and inclination (i~52^○) imply a neutron star mass M_p=1.74_–0.17^+0.20 \textM_☉, smaller (for similar fit assumptions) than that of the well-studied original BW pulsar PSR J1959+2048, which shares similar values of P_s and P_B. This fit, which assumes d~1 kpc, indicates a small heated region on the (anomalously faint) companion. With a free distance and full surface heating the best fit is statistically acceptable, but the large inferred d=4.7±0.3 kpc is inconsistent with the observed pulsar proper motion. Improved photometry and heating models will be needed to refine these measurements.