Astrophysical Sciences and Technology Colloquium: Giants Transiting Giants

Astrophysical Sciences and Technology Colloquium
Giants Transiting Giants: Revealing planet demographics of post-main sequence systems

Dr. Samuel Grunblatt
Johns Hopkins University

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Abstract:
Despite the thousands of planets discovered orbiting stars on the main sequence, the planetary systems of more evolved stars remain poorly understood. Studying planetary systems around subgiant and red giant stars can reveal how main sequence planetary systems respond to stellar evolution over time. Over the last 5 years, the 'Giants Transiting Giants' survey has increased the number of planets known transiting evolved stars by a factor of three. These planetary systems provide testbeds for understanding planet inflation, orbital alignment, decay, and chaotic disruption, planet engulfment and related chemical enhancement of host stars. Recent studies have revealed that the orbital configurations of these systems differ from those of main sequence systems-- planets around evolved stars seem to follow unique period-eccentricity and orbital alignment trends that are not seen in main sequence systems. Furthermore, the discovery of a low-density hot Neptune around a red giant star suggests that these planets are more resilient to atmospheric erosion than previously thought. Currently proposed studies of these and similar systems with JWST and new ground-based facilities will reveal how planet atmospheres respond to the evolution of their host stars in the next few years, and future missions like Roman will identify thousands of these systems and revolutionize evolved system demographics in the upcoming decade.

Speaker Bio:
Originally hailing from Kingston, NY, Dr. Sam Grunblatt is a Research Scientist in the Department of Physics and Astronomy at Johns Hopkins University, where he has worked since 2022. Prior to joining Johns Hopkins, Sam was a Kalbfleisch postdoctoral fellow at the American Museum of Natural History and the Center for Computational Astrophysics in New York City, returning to the city after receiving his Bachelor's degree in Astrophysics from Columbia University in 2013, and his Ph.D. in Astronomy from the University of Hawaii in 2019. Sam's research spans stellar and exoplanet physics and demographics, and he has been leading the 'Giants Transiting Giants' survey using the space-based NASA TESS telescope since 2018, discovering and confirming over 15 planets transiting the unique population of subgiant and low-luminosity red giant stars, as well as conducting asteroseismology on thousands of these stars to determine masses, radii, and ages, and thus the history of these systems to place our understanding of star and planet populations in a Galactic context.

Intended Audience:
Those with interest in the topic. Open to RIT and UofR Physics and Astronomy communities.

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