A moderate spin for the black hole in X-ray binary MAXI J1348-630 revealed by Insight-HXMT

MAXI J1348-630 is a low-mass X-ray black hole binary located in the Galaxy and undergone the X-ray outburst in 2019. We analysed the observation data in very soft state during the outburst between MJD 58588 and MJD 58596 based on the Insight-HXMT observations from 2 to 20 keV via the continuum fitting method to measure the spin of the stellar-mass black hole in MAXI J1348-630. The inner disc temperature and the apparent inner disc radius were found to be 0 . 47 +/- 0.01 keV and 5.33 +/- 0.10 R-g from the observation data modeled by the multicolour disc blackbody model. Assuming the distance of the source D similar to 3.4 kpc , the mass of the black hole M similar to 11 M-circle dot, and the inclination of the system i similar to 29.2 degrees, the spin is determined to be a(*) = 0.41 +/- 0.03 for fixing hardening factor at 1.6 and n(H) = 8.6 x 10(21)cm(-2) . Besides, considering the uncertainty of the parameters D , M , i of this system, with the Monte Carlo analysis, we still confirm the moderate spin of the black hole as a(*) = 0.42(-0.50)(+0.13). Some spectral parameters (e.g. column density and hardening factor) which could affect the measurements of the BH spin are also briefly discussed.