Massive-binary EvoluTion Across the metallicity Ladder

Descripción del proyecto

Comprender las estrellas masivas y los agujeros negros mediante los niveles de metalicidad

¿Las estrellas masivas explotan en supernovas al colapsar en agujeros negros? Todavía existen importantes lagunas en nuestra comprensión de estas estrellas. Ello se debe a la rareza de las binarias masivas y a la falta de datos de seguimiento. El proyecto METAL, financiado por el Consejo Europeo de Investigación, utilizará amplios datos espectroscópicos e interferométricos del Telescopio Muy Grande y del telescopio espacial Hubble para estudiar miles de estrellas masivas de nuestra Galaxia y de las Nubes de Magallanes. El proyecto mejorará nuestra comprensión de las estrellas masivas y los agujeros negros en diferentes niveles de metalicidad, ofrecerá mejores estadísticas sobre estrellas masivas, aumentará la muestra de binarias de agujeros negros inactivos y perfeccionará los modelos de evolución de estrellas masivas y supernovas de colapso del núcleo.

Objetivo

Do massive stars undergo supernova explosions when collapsing into black holes? What mechanisms drove the Cosmos into an epoch of reionization? How was dust produced in the Early Universe? Scarcely any field of astronomy remains unaffected by massive stars: stars born with more than eight solar masses. Yet, studies in the Local Universe reveal substantial gaps in our understanding of massive stars related to mass loss, internal mixing, core-collapse, and stellar interactions. Uncertainties worsen at the low-metallicity conditions of the Early Universe. The primary reason for this: a severe lack of empirical constraints on massive binaries across the metallicity axis, driven by the rarity of massive stars and the shortage of adequate monitoring campaigns to study them.
METAL leverages hundreds of hours worth of novel spectroscopic and interferometric data collected as PI using observatories such as the Very Large Telescope (VLT) and the Hubble Space Telescope, including a VLT Large Programme (116hr; 2023 - 2025). These campaigns monitor thousands of massive stars in our Galaxy and the Magellanic Clouds. Targeting unevolved OB-type stars, evolved Wolf-Rayet and Oe/Be stars, and elusive black holes, METAL will elucidate the initial conditions, evolution, and ultimate fates of massive stars at three metallicity anchors. Groundbreaking outcomes include (1) unprecedented statistics on the multiplicity, initial mass function, and structure of massive stars at low metallicity, (2) a tenfold increase in the sample of dormant black-hole binaries and the first such sample at low metallicity, and (3) a revised mass-loss prescription and a comprehensive binary characterisation of evolved massive stars at two metallicity anchors. The deliverables will be the defining calibrators for next-generation evolution models of massive stars, ushering in advancements in models of not only stellar evolution, but galaxy evolution, unresolved stellar populations, and core-collapse supernova.