Meredith Rawls » Graduate Students

Meredith Rawls

Graduate Student NMSUAstronomy
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Education
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Biographical Info

Research

My main research interest is using binary and variable stars as tools to better understand how all stars live and evolve. Beyond this, I am passionate about quality science education and public outreach for all, enjoy writing, and love getting people excited about astronomy. Visit AstronoMerrdiff to learn more.

Red Giants in Eclipsing Binaries as a Benchmark for Asteroseismology
My Ph.D. thesis explores how observations of eclipsing binaries containing a red giant star can be used as a benchmark for asteroseismic studies. I work with Kepler light curves, echelle spectra, and multiband photometry to create well-constrained photodynamical models and investigate why some of the red giants don’t oscillate when we think they should.

I began working with Jason Jackiewicz and Patrick Gaulme in the Solar, Stellar, and Exoplanet Research Group in 2012. Their expertise is asteroseismology, or more colloquially, starquakes. These oscillations are a window to the interiors of stars, which are otherwise invisible to observers. We are using light curves of eclipsing giant stars from the Kepler mission and ground-based spectra from Apache Point and Kitt Peak Observatories.

I spent the summer of 2011 in Bangalore, India as a participent in the IRES program at the Indian Institute for Astrophysics. While abroad, I became familiar with the binary modeling program PHOEBE and analyzed archival light curves of eclipsing binary stars in the Large Magellanic Cloud with advisor M. S. Rao. I also had the opportunity to visit observatories near Bangalore and eat lots of delicious food!

Refined Neutron Star Mass Determinations for Six Eclipsing X-Ray Pulsar Binaries
The topic of my M.S. thesis at San Diego State was determining neutron star masses in eclipsing X-ray binaries, with advisor Jerry Orosz. We used the Eclipsing Light Curve (ELC; see Orosz & Hauschildt 2000) numerical code to model six systems. Our technique allows an arbitrary number of input parameters to be included in an orbital solution. ELC also employs a key improvement over analytic methods: it uses Roche geometry with equipotential surfaces to more accurately model optical light curves and the X-ray eclipse duration. Our results show a clear distribution of neutron star masses that range from ~0.9–2 solar masses.

My senior thesis at Harvey Mudd was titled Ups and Downs in the Life of a Cataclysmic Variable: The Long-Term Behavior of CM Phoenicis, completed with advisor Don Hoard. I combined optical and near-infrared photometry of an unusual cataclysmic variable star with optical spectroscopy to explore the secular evolution of an interacting binary star. Our analysis showed transitions between bright and faint states, and we classified CM Phe as a VY Scl-type system. This work was complemented by a summer project at the Carnegie Observatories spent deriving photospheric chemical composition for metal-poor globular cluster stars from high resolution spectra. I traveled twice with Inese Ivans to Las Campanas Observatory in Chile, and took control of the Clay Magellan 6.5-meter telescope for two nights to obtain high-resolution optical spectroscopy.

I also assisted in the analysis of supernova light curves during a semester abroad at Moscow State University in Moscow, Russia. I have a basic understanding of the Russian language.

 

Publications

Testing Asteroseismic Scalings for Red Giants With Eclipsing Binaries Observed by Kepler
P. Gaulme, J. McKeever, J. Jackiewicz, M. L. Rawls, E. Corsaro, J. Southworth, S. Mahadevan, C. Bender, & R. Deshpande
2016, The Astrophysical Journal, Submitted (as of July 2016)

KIC 9246715: The Double Red Giant Eclipsing Binary With Odd Oscillations
Meredith L. Rawls, P. Gaulme, J. McKeever, J. Jackiewicz, J. A. Orosz, E. Corsaro, P. G. Beck, B. Mosser, D. W. Latham, & C. Latham
2016, The Astrophysical Journal, 818, 108

Red Giants in Eclipsing Binaries and Multiple-star Systems: Modeling and Asteroseismic Analysis of 70 Candidates from Kepler Data
Patrick Gaulme, J. McKeever, M. L. Rawls, J. Jackiewicz, B. Mosser, & J. A. Guziik
2013, The Astrophysical Journal, 767, 82

Refined Neutron Star Mass Determinations for Six Eclipsing X-Ray Pulsar Binaries
Meredith L. Rawls, J. A. Orosz, J. E. McClintock, M. A. P. Torres, C. D. Bailyn, & M. M. Buxton
2011, The Astrophysical Journal, 730, 25

 

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