[phas-dept] Oct. 12 (Thursday) 4 PM - Physics and Astronomy Colloquium

[Heungman Park]

Fall 2017 Colloquium

Department of Physics & Astronomy, TAMU-Commerce

Oct 12, Thursday, 4-5 PM in Science Building 127

(coffee and cookies will be served at 3:50 PM)

Astronomy

Calibrating white dwarf asteroseismic fitting techniques
Dr. Barbara Castanheira Endl

Baylor University and University of Texas at Austin

[https://urldefense.proofpoint.com/v2/url?u=https-3A__lh6.googleusercontent.com_HhC7-5FBTfxF5URJUa2fwq83rnkpMWuikgQ7RP0-5FNEhWF3CxKwxa2PszvuejKYItDxU0TeKLtrhXuZxN6lTKZNI4N4PpL4J8OqnFmoohV57X7-5F5rwOeJE6C7E1XXypbOGNZ1MSLN1M&d=DwIFAw&c=oqyuZuih6ykib6aKiBq22_bich4AVfYGoLertJN0bEc&r=hjwEO_XYlnwAQWUGeaCrW47w4mK-Al28-BKyRvaivBs&m=kTHICdmylEP1gixzy7vAldhqLChFcz_qPU4f9B7aoio&s=OOLeaYkji2-CiY2ePNFKUnYvCsxRihulgMuyrdlY0lo&e= ]

Dr. Endl earned her BS (2002), MS (2003), and PhD (2007) from Federal University of Rio Grande do Sul (UFRGS) in Brazil. She studied on white dwarf and pulsating stars on her PhD thesis. She was a postdoctoral researcher at the University of Vienna, Austria and the University of Texas at Austin, USA. She did research on pulsating stars and spectroscopy of white dwarf stars during her postdoctoral period. Currently she is a lecturer at Baylor University. She has published more than 60 journal papers.



Abstract

The main goal of looking for intrinsic variability in stars is the unique opportunity to study their internal structure. Once we have extracted independent modes from the data, it appears to be a simple matter of comparing the period spectrum with those from theoretical model grids to learn the inner structure of that star. However, asteroseismology is much more complicated than this simple description. We must account not only for observational uncertainties in period determination, but most importantly for the limitations of the model grids, coming from the uncertainties in the constitutive physics, and of the fitting techniques. In this presentation, we will discuss results of numerical experiments where we used different independently calculated model grids (white dwarf cooling models WDEC and fully evolutionary LPCODE-PUL) and fitting techniques to fit synthetic stars. The advantage of using synthetic stars is that we know the details of their interior structure so we can assess how well our models and fitting techniques are able to  the recover the interior structure, as well as the stellar parameters.


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