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Research

I study a few different types of variable stars, primarily novae and Type Ia supernovae. I'm interested in their behavior before and after their eruptions/explosions, and I use a combination of different telescopes and archival data sources to better understand their life cycles. To see what I've been working on most recently, check out the Publications tab.

Research Students

Current Students at CofC

  • None at the moment--I'm on sabbatical

(If you are a CofC undergrad interested in working with me, please reach out and we will discuss the possibilities.)

Former Students

  • Undergads at CofC: Katherine Bruce, Bridget Ierace, Lucy Williamson, Ashley Dowd, Rebecca Houck, Jaime Wright, Seth Zoppelt, Eliza Frankel, Cameron Fish, Thomas Guy, Lucas Moyon
  • Master's Students/Future High School Teachers, through the AMNH Masters of Arts in Teaching Program: Chris Cubelo, Victoria Jones, Bart Piscitello, Melissa Shumer, Eugene Viderman, Katie Warner (2013); Kenneth Egri, Ariel Goerl, Noah Kaminsky, Tamara Machac (2014); Rebecca Eidelman, David-anthony Murray, Meg Stewart, and Kathleen Wilcox (2015)
  • High School Students, through the AMNH Student Research Mentoring Program: Dong Yi Chen, Lucien Christie-Dervaux, Julia Kruk, Zachary Murray (2013-2014); Jonah Gilbert, Wilson Hernandez, Rocco Rinaldi-Rose, Emre Yorgancioglu, (2014-2015); James Garland (2015-2017)
  • REU Students: Zachary I. Edwards (LSU REU)

(Bolded names indicate students who are co-authors on published research papers.)

Thesis Research

My thesis title was "Recurrent Novae and Type Ia Supernova Progenitors" and it is freely available on the LSU Electronic Theses and Dissertations website. (All of the chapters have been published in various refereed journals; be sure to use the numbers from the most recent publication.) My thesis brings together four projects I worked on as a graduate student and combines them with other new research to take a fresh look at the Type Ia supernova progenitor problem. Although we've empirically calibrated SN Ia lightcurves, turning them into the most useful standard(izable) candles and using them to discover the acceleration of the expansion of our universe, we still don't know exactly where they come from. There must be at least one carbon-oxygen white dwarf, and it must be near the Chandrasekhar mass limit, but the identity of the companion star that donates the material needed to push the WD over the limit, causing the Ia explosion, has been a mystery for decades.

Recurrent novae have been promising progenitor candidates for many years, but our research shows that they can account for at most ~50% of the observed Ia explosions. Our headline result, published in Nature, shows that a Ia explosion that occurred in the Large Magellanic Cloud ~400 years ago must have had a double-WD progenitor.

At this point, we know that at least one system had a double-WD (double-degenerate) progenitor, but we cannot at this point extend that to all SNe Ia. What is looking to be ever more likely is that there are two types of systems that provide the SNe Ia (the dual-channel hypothesis): half coming from single-degenerate systems (such as RNe) and half from double-degenerate systems.

Most recent update to this particular page: 5 October 2023