On Thursday, February 9, CIERA Postdoc Anna Childs was invited onto SETI Live (weekly live-streamed discussions about ongoing research, education projects, and science news) to talk about the research she started as a graduate student at the University of Nevada, Las Vegas with Dr. Rebecca Martin and Dr. Mario Livio. The SETI Institute‘s mission is “to lead humanity’s quest to understand the origins and prevalence of life and intelligence in the universe and share that knowledge with the world”.
“We were interested in evaluating the likelihood that terrestrial planets around M-dwarfs would experience asteroid impacts, similar to what the Earth experienced during the late heavy bombardment period, and the implications this has for life around M-dwarfs,” said Anna. “It is thought that in the solar system, Jupiter and Saturn are responsible for our asteroid belt and for the asteroid impacts that Earth experienced shortly after its formation and that these asteroid impacts are what brought Earth its water and also helped contribute to Earth’s habitability in other ways. So, if asteroid impacts are necessary for life, then it’s important to understand if planets around M-dwarfs are likely to experience asteroid impacts since planets around M-dwarfs are the main targets in the search for life. To begin to answer this question, we looked at the planetary architectures around M-dwarfs using data from the Exoplanet Archive. We were specifically looking for systems that had giant planets exterior to the system’s snow line and terrestrial planets interior to the snow line. A system with this planetary architecture would indicate that the system also had/has an asteroid belt, the mechanisms to deliver asteroids to the inner regions, and inner terrestrial planets to experience asteroid bombardment. We found no systems around M-dwarfs, or K-dwarfs, that met this criterion. However, we found five such systems around G and F-type stars. This dichotomy in planetary architecture around smaller and larger stars may indicate a difference in planet formation pathways and also that if life does require asteroid impacts (which is a big if!) then it is unlikely that planets around M-dwarfs will harbor life.”
“When I first started graduate school, I had the opportunity to intern at NASA Ames in Mountainview, CA which is also where SETI is located. My mentors, Elisa Quintana and Tom Barclay, would take me to the monthly SETI talks. This is what first sparked my interest in both SETI and the search for extraterrestrial intelligence! Being able to contribute to the institute that helped shaped my career pathway was a very special experience for me. I met the Director of Communications, Rebecca McDonald, at the SETI booth at the January 2023 American Astronomical Society meeting and told her about my work and she thought it would be a good fit for SETI live!”
For her future work, Childs would like to focus on planet formation around low-mass stars to help better understand why system architectures around low mass stars are different from our solar system.