Scialog: Collaborative Teams - 2017
The Stellar MRI
We still have much to learn about the life and death of stars. For example, we’ve known since the time of Galileo that stars rotate around their axis. However, we do not know how the rotation of a star and its various layers, which can rotate at different rates, affect its evolution and final death.
Astrophysicists Matteo Cantiello, Flatiron Institute, NYC, and Jeffrey Oishi, Bates College, recently formed a team and won a funding competition that will allow them to study some of the physics affecting rotating stellar interiors. They are particularly interested in a process called magnetorotational instability (MRI), which can arise in the presence of differently rotating layers in the interior of a star, and play a fundamental role in shaping the evolution of its rotational properties.
Since as it evolves a star burns its fuel from the inside out, heavier ashes can be found in the interiors while lighter unburned material is stored in the outer regions. Thus a star can be compared to an onion-like structure composed of multiple concentric layers, or “shells,” of slightly different composition surrounding a very hot core. Each shell can also rotate at a different rate based on a number of physical processes that can “connect” these different layers. As the star evolves (a star can live from a few millions to many billions of years) these processes slowly shape and determine the evolution of its interior rotation.
One of these processes is the MRI. Cantiello and Oishi will investigate the role of the MRI in stars using simulations that account for the important physical ingredients that distinguish rotating stellar shells, including their different rotation rates and composition.
“This project could lead to the solution to a long-standing problem in stellar astrophysics,” the researchers said, including the ability to make predictions about the conditions of a star’s core before it collapses. This is particularly important to determine which type of (explosive) death the star will undergo.
The two scientists formed their collaboration at an RCSA-sponsored conference, Scialog: Time Domain Astrophysics, held late last year in Tucson, Arizona. There, 50 leading young astronomers and astrophysicists, joined by 10 distinguished senior scientists, engaged in intensive discussions designed to produce creative ideas for innovative research. (Scialog is a combination of “science” and “dialog.”)
“Scialog aims to encourage collaborations among theorists, experimentalists and computational scientists,” said RCSA Program Director Richard Wiener. “We want to catalyze the development of a community in which theory and observation work together to achieve understanding of fundamental phenomena.”