Does the Geometry of Keperian Disk Vary during the Outbursts of a Transient LMXB?

The central object in a low-mass X-ray binary (LMXB) accretes matter from its companion star mainly via Roche lobe overflow; the Keplerian disk, having high angular momentum and high viscosity becomes instrumental in overall accretion. In the same transient LMXB, the accumulation radius, from where matter rushes towards the black hole due to thermal-viscous instability, may be different in different outbursts. Using RXTE/ASM long-term data and employing a simple timing analysis, we examine more than a dozen outbursts in transient LMXBs, exhibiting either multiple outbursts (GX 339-4 and H 1743-322) or sporadic outbursts (e.g. 4U 1543-47, etc.). It is found that the Keplerian disk indeed varies in its size from an outburst to another; this, in turn, dictates the brightness of outbursts. Both canonical and anomalous/failed outbursts can be distinguished from our results. Outbursts, in general, are shown to fall into two types, based on four features observed by us.