The Nature of Classical Be Star Outbursts: A Multi-Epoch Study of the Be system EPIC 202060631

Through cross-matching the ASASSN photometric light curves and LAMOST spectroscopic observations, we serendipitously captured a rare major outburst event from the Be star EPIC 202060631, lasting over 1000 days. Fortuitously, the LAMOST ow-resolution spectra densely covered the flux rising stage with 20 epochs, while an additional 7 low-resolution and 11 medium esolution spectra monitored the subsequent decay phase. Moreover, this target was observed by Kepler telescope in its K2 mission when before the outburst and by TESS telescope while after returning to quiescence. Analyses of these datasets reveal pulsation behavior and mode amplitudes, indications of radial and tangential motions in the photosphere, and clear evidence of mass ejection and circumstellar disk formation. We modeled the central star using the BRUCE04 code and analyzed the disk structure using HDUST. Our results suggest episodic mass injection events from the central star triggered the disk buildup and carried imprints of the changing stellar pulsations. This study offers unique insights into the connections between photospheric activities, disk evolution, and stellar rotation during Be star outbursts.