Probing the Atmosphere of the Sun-As-A-Star Using Seismic Waves

At the turn of the 21st century, helioseismology was extended to other stars as asteroseismology, emerging as a powerful tool to study the physical processes in stellar interiors. This field gained further momentum with the advent of space missions such as CoRoT and Kepler. These missions have enabled us to probe internal properties of stars, such as density, composition, rotation, and convective mixing, which are challenging to acquire using spectroscopy and photometry. However, while current asteroseismic analyses provide insights into stellar interiors, the atmospheres of stars have remained largely unexplored. Here we present a groundbreaking approach to probe stellar atmospheres. By analyzing Doppler velocity data from two spectral lines with different formation heights in the atmosphere, we can model the propagation of acoustic waves between these heights. This method, extensively utilized on the Sun's surface to estimate atmospheric properties, is adapted here to simulate solar data as if it were from a distant star. Our analysis sets the stage for seismic probing of stellar atmospheres beyond the Sun. Preliminary results reveal promising avenues for studying the sound speed (temperature), radiative cooling times (energy transport), and magnetic cycles (stellar dynamos), all of which are crucial for stellar modeling efforts. This research opens new doors for probing stellar atmospheres in ways never before possible.