Shanghai Astronomical Observatory Astrophysics Colloquium

Title：A possible planet formation imprint: chemically depleted stars are magnetically more active

Speaker：Jie Yu（Australian National University）

Time：3:00 pm July 31th (Wednesday)

Tencent Meeting：548-125-411 password: 6360

Location: Lecture Hall, 3rd floor

Abstract：

Stellar chemical anomalies have long been considered a tell-tale sign of the interaction between stars and planets. Exoplanet formation may induce chemical depletion in host stars compared to those without planets, while exoplanet engulfment can result in chemical enrichment. Both processes could create rather similar differential signals. In this study, aiming to observationally disentangle these two planetary processes, we explore the magnetic activity of 125 pairs of co-moving stars from the C3PO program using exquisite spectra from the Magellan, Keck, and VLT telescopes. We find that for systems exhibiting significant differential chemistry, their elemental abundance differences are inversely correlated with differential magnetic activity. The significance of this inverse correlation increases with condensation temperature. Additionally, the correlation between elemental abundance difference and condensation temperature is stronger for younger stars. These observations indicate that the chemical anomaly signature is likely caused by planet formation. Our findings offer new clues into the origin of chemical anomalies present in stellar twins.

CV：Jie Yu is a research fellow at the Australian National University, working on asteroseismology, magnetic activity, exoplanets, and interstellar reddening. He obtained his PhD from the University of Sydney in 2019. Following his doctoral studies, he worked as a postdoctoral research scientist at the Max Planck Institute for Solar System Research and the Heidelberg Institute for Theoretical Studies. He was also an active member of the ESA PLATO space mission. Currently, he leads an asteroseismology group for the Chinese Earth 2.0 space mission.