Events

Thoughts on 50 years of eruptive phenomena in early stellar evolution

NOIRLab South Colloquia

Lee Hartmann (University of Michigan)

We now recognize that protoplanetary disks can undergo outbursts of rapid

accretion, in some cases resulting in mass flows of 10^-4 solar masses

per year lasting for decades or a century. The largest such bursts might result

from heating by gravitational instability leading to thermal ionization sufficient

to activate the magnetorotational instability, but what triggers the MRI in small

outbursts is not clear. I will briefly review how we came to understand that these events

are disk accretion outbursts, and then move to current puzzles, including

new constraints on how protostars accrete from their disks.