The Pre-Main-Sequence stellar evolution is shaped by the mass accretion process, which is known for its highly unstable nature. In fact, most of the stellar mass is gathered during "episodic accretion" bursts, which solved the luminosity spread of young clusters. As a consequence of the accretion bursts, eruptive behaviours have been observed on Young Stellar Objects (YSO), such as the decades-long and high-amplitude FUor-type events. Many numerical models are proposed to reconstruct these rarely-seen events, although more observational evidence is truly desired. In this talk, I will present our latest search results for these outbursts using long-lasting photometric surveys (e.g. VVV/VVVx, Gaia, NEOWISE, etc). Specifically, we confirmed 15 new FUors using the recent near-infrared VVV data, which enlarged the total known sample of FUors by ~30%. We found that compared to other types of outbursts on YSOs, FUors have distinct characteristics such as fast-rising, high-amplitude and long-lasting.
Dr Zhen Guo (郭震) obtained his PhD from Peking University under the supervision of Prof. Greg Herczeg, working on the topic of variable young stars. After his PhD, he worked as a Postdoctoral researcher at the University of Hertfordshire (UK) as a team member of the ESO VVV survey. Currently, he is a Fondecyt Research Fellow in Chile, working at the Universidad de Valparaiso. He is also a young researcher in NPF at Universidad Tecnica Federico Santa Maria (Chile). Zhen's research interests focus on the Galactic variable stars, specifically on variable young stellar objects.
Host: Sharon Xuesong Wang
