Challenging the disk instability model: long outbursts from neutron star low-mass X-ray binaries

Some neutron star low-mass X-ray binaries with short orbital periods (~hours) show outbursts lasting far longer than expected. A notable example is EXO 0748-676, which remained in outburst for 23 years before entering a long quiescence and re-emerging recently, 16 years later. This study explores why such systems can sustain extended outbursts despite having smaller accretion disks and challenges the currently accepted disk instability model. [Bhattacharya, S. and Bhattacharyya, S., 2024, in preparation].