Astronomy Seminar: Stellar Evolution at the Crossroads
Background Image Credit:
Two stars orbit each other within an enormous dusty disk in the U Monocerotis system, illustrated here. When the stars are farthest from each other, they funnel material from the disk’s inner edge. At this time, the primary star is slightly obscured by the disk from our perspective. The primary star, a yellow supergiant, expands and contracts. The smaller secondary star is thought to maintain its own disk of material, which likely powers an outflow of gas that emits X-rays.
Credits: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR)
Download high-resolution video and images from NASA’s Scientific Visualization Studio
Two stars orbit each other within an enormous dusty disk in the U Monocerotis system, illustrated here. When the stars are farthest from each other, they funnel material from the disk’s inner edge. At this time, the primary star is slightly obscured by the disk from our perspective. The primary star, a yellow supergiant, expands and contracts. The smaller secondary star is thought to maintain its own disk of material, which likely powers an outflow of gas that emits X-rays.
Credits: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR)
Download high-resolution video and images from NASA’s Scientific Visualization Studio
Abstract:
RV Tauri variables are luminous pulsating supergiant stars with temperatures ranging between 4000 – 6000 K. They extend the brightest part of the Type II Cepheid period-luminosity relationship, which may be used as standard candles. Binarity plays a key role in the dynamics and evolution of these objects as they transition into planetary nebulae. I will present multiwavelength observations of two archetypical RV Tauri systems and discuss our findings. We used Kepler observations of DF Cygni, the only RV Tauri system in Kepler's original field-of-view, and its spectral energy distribution to provide evidence for disk obscuration. I will also discuss how our XMM-Newton data makes U Monocerotis (U Mon) the first RV Tauri system detected in X-rays. Combining historic Harvard photographic plates (DASCH) data and observations from American Association of Variable Star Observers (AAVSO), we extended U Mon’s photometric time-series baseline back to the late 1880s.
Speaker:
Laura D. Vega, Postdoctoral Researcher at NASA Goddard Space Flight Center and the University of Maryland, College Park
Speaker bio >>
Astronomy Seminars
Astronomy/Astrophysics seminars are held (roughly) weekly on Fridays at 2 pm (ET) on campus in Washington DC.
The seminar is fairly casual, and the audience is mostly astronomers, with some cosmochemists or geophysicists occasionally. The seminar will be hosted in a Hybrid format for Spring 2023.
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