#author("2023-04-18T04:43:50+00:00","default:wwwadm","wwwadm")
[[IoA_Seminar]]
#contents
* 講演リスト [#g8648f7a]
** No. 400: 6 th Apr. 2023 (Thu) 15:30-16:30 [#n2f92204]
*** Speaker: Doug Johnstone (Principal Research Officer, Herzberg Astronomy and Astrophysics Research Centre and President’s Science Advisor, National Research Council Canada) [#qba3fbc6]
*** Title: What the Variability of Embedded Protostars Tells Us about Accretion: Past, Present, and Future [#l6afbc71]
Language: English
Abstract: The James Clerk Maxwell Telescope (JCMT) has been monitoring eight nearby
low-mass star-forming regions in the Gould Belt at submillimetre
wavelengths for over six years to search for and quantify the time
dependent brightness variability of the resident deeply embedded
protostars. Secular variability is common among these protostars; greater
than 25% of the sample show measurable long-term brightness changes and 10%
show burst behaviour lasting months to years. We interpret this secular
variability as reflecting changes in the mass accretion rate from the disk
to the protostar, as predicted by theoretical models of (proto)stellar
assembly. For a subset of our sample we have contemporaneous mid-IR
light-curves which allow additional constraints on the conditions
responsible for the brightness variations, confirming that the
submillimetre variability is driven by changes in the dust temperature
profile of the envelope. Furthermore, we have combined, for one source,
single dish and interferometric sub-mm monitoring, which has allowed us to
unambiguously recover a time lag in the variability at larger angular
scales and use the results to confirm the envelope structure surrounding
the embedded protostar. More recently, we have added somewhat more distant
intermediate mass regions to our JCMT monitoring and collaborated with the
Maser Monitoring Organization (M2O) in follow-up of more massive protostar
candidate variables.
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