Accretion in protostars: From FUor outbursts to massive star formation

by Dr Jyotirmoy Dey (DAA, TIFR)

Tuesday 18 Aug 2026, 16:00 → 17:00 Asia/Kolkata

AG-66

Accretion is the fundamental process driving protostellar evolution, yet its mechanisms differ dramatically across the stellar mass spectrum. In this talk, I present multiwavelength observational evidence for accretion-related phenomena in both low- and high-mass star-forming environments, and introduce our ongoing campaign targeting episodic accretion in high-mass protostars. I begin with a low-mass FU Orionis system that underwent a dramatic outburst almost a decade ago, where ALMA Band 6 observations reveal spiral arms and molecular line kinematics consistent with a large-scale accretion streamer channeling material from over thousands of AU. This suggests that episodic accretion in low-mass protostars may be regulated by externally driven infall rather than internal disk instabilities alone. I then present a study of the high-mass star-forming region G28.288−0.364, where uGMRT, GLOSTAR, and ALMA observations resolve a population of H ii regions and dust cores at distinct evolutionary stages, including a rare transitional object between the hypercompact and ultracompact H ii region phases, a critical, short-lived epoch in massive star growth. Finally, I introduce our coordinated monitoring campaign using the 2-m Himalayan Chandra Telescope and 3.6-m Devasthal Optical Telescope in the near-infrared, complemented by maser monitoring with the Irbene radio telescope, aimed at detecting accretion-driven variability in massive young stellar objects and connecting it to the FUor phenomenon seen in their low-mass counterparts.