We present an in-depth spectral and timing analysis of the Black Hole binary 4U 1630-472 during 2016 and 2018 outbursts as observed by AstroSat and MAXI .
The extensive coverage of the outbursts with MAXI is used to obtain the Hardness Intensity Diagram ( HID ) .
The source follows a ‘ c ’ -shaped profile in agreement with earlier findings .
Based on the HIDs of previous outbursts , we attempt to track the evolution of the source during a ‘ super ’ -outburst and ‘ mini ’ -outbursts .
We model the broadband energy spectra ( 0.7 - 20.0 keV ) of AstroSat observations of both outbursts using phenomenological and physical models .
No Keplerian disc signature is observed at the beginning of 2016 outburst .
However , the disc appears within a few hours after which it remains prominent with temperature ( T _ { in } ) \sim 1.3 keV and increase in photon index ( \Gamma ) from 1.8 to 2.0 , whereas the source was at a disc dominant state throughout the AstroSat campaign of 2018 outburst .
Based on the HIDs and spectral properties , we classify the outbursts into three different states - the ‘ canonical ’ hard and soft states along with an intermediate state .
Evolution of rms along different states is seen although no Quasi-periodic Oscillations ( QPOs ) are detected .
We fit the observed spectra using a dynamical accretion model and estimate the accretion parameters .
Mass of the black hole is estimated using inner disc radius , bolometric luminosity and two component flow model to be 3 - 9 M _ { \odot } .
Finally , we discuss the possible implications of our findings .