IAA Severo Ochoa Colloquium this Thursday
Seminarios IAA
IAA Severo Ochoa Colloquium
Date: Thursday, 21 May, 12:30 CEST
Place: Salón de Actos
Origin and impact of protostellar outflows: the ALMA and JWST revolution
The birth of stars, and of planets around them, is universally associated with a spectacular bipolar ejection phenomenon that extends from stellar to parsec scales. Its manifestations include a narrow and fast axial jet, surrounded by a broader and slower molecular outflow carrying a large amount of mass. The exact origin of these dual phenomena, their role in the removal of excess angular momentum, and their impact on star and planet formation, have all been a subject of fierce debate and active research over four decades. In this talk, I will review major progress on these topics obtained from new observational facilities (from the optical to the millimeter range) and from enhanced modeling capabilities. In particular, I will highlight recent results from ALMA and JWST and how they could revolutionize our understanding of the origin and impact of protostellar outflows.
Seminarios IAA
IAA Severo Ochoa Colloquium
Date: Thursday, 28 May, 12:30 CEST
What the Variability of Embedded Protostars Tells Us about Accretion: Past, Present, and Future
The James Clerk Maxwell Telescope (JCMT) has been monitoring eight nearby low-mass star-forming regions in the Gould Belt at submillimetre wavelengths for more than eight 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.