The history of C, N, and O in the Galaxy
DAINA3 research grant of the Polish National Science Center and the Research Council of Lithuania.
Project Reg. Nr.: 2024/52/L/ST9/00220
Principal investigators
dr hab. Rodolfo Smiljanic (Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Poland)
doc. dr Šarūnas Mikolaitis (Institute of Theoretical Physics and Astronomy, Vilnius University, Lithuania)
Team members
SAGA Team
VU ITPA: Dr. Arnas Drazdauskas, Dr. Markus Ambrosch, Dr. Carlos Viscasillas-Vázquez, PhD Student Barkha Bale, PhD Student Bruno Ćurjurić, PhD Student Vilius Bagdonas
The aim of this project is to conduct a comprehensive, homogeneous, and precise analysis of the abundances of carbon, nitrogen, and oxygen (CNO) in a large set of stars belonging to all main Galactic stellar populations. We will use the results to investigate the chemical enrichment history of these elements and explore the effects of evolutionary mixing processes on their abundances in stellar atmospheres.
Apart from hydrogen and helium, both of which are produced in primordial nucleosynthesis a few minutes after the Big Bang, carbon, nitrogen, and oxygen are the three most abundant elements in the Universe. These three elements are essential for life as we know it. They are part of all the main molecules that are currently considered biomarkers in exoplanetary atmospheres (e.g. CO2, H2O, CH4, and N2O). Therefore, understanding the origin and history of CNO also has implications for the quest to find life in the Universe.
To achieve our goal, we propose an ambitious analysis strategy based on our previous experience and recent methodological developments. Our sample consists of a combination of spectra from new observations with publicly available data from several stellar surveys. We will use a set of reference stars with accurate stellar parameters, to ensure the accuracy of the results obtained from the new spectra. Moreover, the same set of reference stars will be used to improve the accuracy of the stellar parameters and the precision of the abundances available from large surveys, following calibration methods that we developed in previous work.
Furthermore, accurate parameters will also allow for the determination of stellar ages with a precision of 10% using isochrones.
Combining abundances, ages, and stellar orbits, we will perform a stellar population and radial migration analysis to pinpoint the Galactic region of origin of the stars in the sample. In this way, we can investigate for the first time the local details of the CNO enrichment as a function of the Galactic radius in a large volume of the Milky Way. Moreover, on the stellar evolution side, precise abundances and ages, together with the measurement of activity indicators, will be key to providing a better understanding of the effects of magnetic activity in stellar mixing processes, something still missing.
Together, these efforts will help to clarify with unprecedented detail the intricacies of the history of C, N, and O in the Galaxy, providing important input to improve models of Galactic and stellar evolution.