Student: Kristie Nault, graduate student in Astrophysics, University of Iowa
Faculty Advisor: Dr. Casey DeRoo
A Spectroscopic Study of the Symbiotic Star AG Draconis
My research focuses on the symbiotic star system AG Draconis (AG Dra), which consists of a red giant star and white dwarf. Most stars are low-mass and will go through each of these evolutionary phases at the ends of their lives, and stars are also commonly born in binaries. However, despite supposedly being common, high-quality observations of these stars in the high energy part of the electromagnetic spectrum remain a rarity, since soft X-ray spectra are easily absorbed by interstellar material. With the lack of observations and data, fundamental questions regarding these stars remain unanswered, including the origin and variation of the soft X-rays and the final outcome for these systems. Better knowledge of symbiotic stars may be the key to understanding the progenitors of Type Ia supernovae and the last stage in evolution for the majority of binary star systems. Under the guidance of Dr. Casey DeRoo, my research seeks to directly address these major open questions. I am analyzing high-resolution spectral data for AG Dra by the Chandra X-ray Observatory and Hubble Space Telescope, utilizing two of NASA’s great observatories in tandem for a deeper understanding of these types of stars. This research relates to the mission of NASA’s Astrophysics Division of the Science Mission Directorate because my work seeks to understand this common stellar system and the progenitor systems for Type Ia supernovae, which are an important cosmological distance marker.