MR. JOE PHILIP NINAN

Outflows driven by accretion from protoplanetary discs in the young protostars are expected to have a tight correlation with the accretion rate. The origin of repeated knots seen in outflows from young stellar objects has been hypothesized to be fossil evidence of the past episodic accretion events. These rare events of heavy accretion which last only a few years (in case of EXors) to decades (in case of FUors) could also potentially solve many open puzzles in low-mass star formation, namely "Luminosity Problem", CAIs and Chondrule formation seen in comets etc. The short time variations in the FUors and EXors make them the perfect laboratory to test various low-mass disc outflow models. In this second talk on FUors and EXors, The speaker shall discuss some of the recent observational results that we have obtained from our long-term monitoring of V899 Mon, a peculiar eruptive YSO. He shall mainly discuss the detection of episodic outflows from this source and an attempt to understand which physical outflow mechanisms might be driving these outflows in this eruptive YSO. The short time variations in V899 Mon make it the perfect laboratory to test various low-mass disc outflow models as well as magnetospheric accretion simulations. He shall also present the results from our multi-epoch SALT-HRS spectra, where we have detected changes in the outflow winds at velocities which have never been seen in YSOs. These results are possibly the first detections of magnetic-driven winds similar to weak propeller regime outflows predicted by some simulations. Estimation of the rate at which these episodic outbursts occur is the most crucial parameter to quantify their effect on star and planet formation. In the second half of his talk, he shall present hierarchical Bayesian model he developed for tackling this problem. This model is powerful enough to predict the periods by incorporating long-term multi-epoch, multi-wavelength photometric data available from the data archives of the last century.