[Mesa-users] UVic Star Talk April 12: Earl Bellinger - What can asteroseismology do for astrophysics?

[Falk Herwig]

I think there were some folks from this list attending at the last seminar, and I did not hear objections, so here is our next talk of potential interest to the MESA users:

Monday, May 3rd, 2021, 2PM PST

Join Zoom Meeting
https://uvic.zoom.us/j/82203756592

Trevor Dorn-Wallerstein
Astronomy Department
University of Washington

Title: New Phenomena in Evolved Supergiants Revealed by TESS

Abstract: Massive stars drive the radiative, chemical, and kinematic evolution of their host galaxies. Despite the importance of these stars, the physical factors that govern their progression through the exotic evolved states that we observe them in are poorly understood. Thanks to TESS, high-quality light curves of massive stars in their evolved stages are revealing never-before-seen phenomena that may help answer our most urgent questions. In this talk, I will discuss the two “flavors” of variability revealed by TESS in cool supergiants and how they impact our understanding of massive stellar evolution: Stochastic low frequency variability (SLFV) previously known to exist in O and B stars appears to be ubiquitous across the upper HR-diagram. Simultaneously, we have found a new class of variable yellow supergiants that pulsate with frequencies above ~1 d^-1. Both of these discoveries open the intriguing possibility of probing the interiors of massive stars in their final phases before core collapse. Finally, I will highlight our ongoing work coupling TESS data with high resolution spectroscopy to determine the nature of SLFV in cool supergiants.


http://csa.phys.uvic.ca/star-talks/new-phenomena-in-evolved-supergiants-revealed-by-tess


On Apr 10, 2021, at 7:56 PM, Falk Herwig <fherwig at uvic.ca<mailto:fherwig at uvic.ca>> wrote:

Dear Mesa community - we are running an online Zoom stellar physics seminar at UVic and as an experiment I thought I announce our next talk here, in case there is interest.

Do people think the mesa list is an appropriate place to share such information?

The next UVic Star Talk is Monday 04/12  2pm PDT

Earl Bellinger, Stellar Astrophysics Center, Aarhus, Denmark

Title: What can asteroseismology do for astrophysics?

Abstract: Asteroseismology, the study of stellar oscillations, has emerged as the best way to characterize the global properties of stars, such as their mass, radius and age. Beyond being interesting in their own right, these measurements are essential for a variety of endeavours throughout astrophysics, such as exoplanetology and galactic archaeology. For the very best-observed stars, it is possible to additionally measure some aspects of the internal stellar structure, such as the density and sound speed profile throughout the stellar core. These measurements provide the exciting opportunity to test the physics of stellar evolution, as different physics assumed in stellar evolution simulations may result in the same global properties of stars but a different internal stellar structure. These asteroseismic tests can range from assessing proposed mixing mechanisms in stellar interiors, to measuring cosmological effects such as a time-variable gravitational constant. In this seminar, I will give an accessible review of asteroseismology, and highlight the progress that is being made toward mapping out the interior structures of stars.

Zoom: https://uvic.zoom.us/j/82203756592

Meeting ID: 822 0375 6592




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