Atmospheric parameters and chemical abundances of young stars with APOGEE – I. Orion star-forming region
Journal article, 2025
We derive atmospheric parameters and chemical abundances in young G-, K-, and M-type stars (temperatures between 6500 and 3100 K) using infrared APOGEE-2 spectra. Atmospheric parameters were determined for 548 young stars in the Orion complex (Orion A, B, OB1, and λ Ori) using the TONALLI code. For 340 slow rotators (υ sin i ≤ 30 km s-1), we derived C, Mg, Si, K, Ti, and Fe abundances using 19 atomic lines, MARCS model atmospheres, and BACCHUS. To mitigate the impact of circumstellar material, we excluded stars with infrared excess identified via 2MASS and WISE photometry. We find subsolar [X/H] abundance ratios, consistent across elements and among all four groups, suggesting a chemically homogeneous Orion complex. We computed [α/Fe] from [Mg/Fe], [Si/Fe], and [Ti/Fe], obtaining a median of -0.14 ± 0.04$, about 0.10 dex lower than the value for nearby main-sequence stars (-0.04 ± 0.04) at similar [Fe/H]. This result aligns with predictions from Galactic chemical evolution models. Furthermore, the median [C/H] abundance we derived for Orion agrees with previous estimations based on the analysis of the ionized gas of the Orion nebula. This work sets the stage for extending the analysis to stars with circumstellar material and higher rotational velocities, which will not only improve our understanding of Orion, but also provide critical insight into the formation and evolution of young stars, as well as the chemical evolution of the Milky Way.
stars: pre-main-sequence
stars: abundances
infrared: stars
stars: fundamental parameters
Author
Ricardo López-Valdivia
Universidad Nacional Autónoma de México
Lucía Adame
Universidad Nacional Autónoma de México
Carlos G. Román-Zúñiga
Universidad Nacional Autónoma de México
Jesús Hernández
Universidad Nacional Autónoma de México
Edilberto Sánchez
Universidad Nacional Autónoma de México
Itzarel Herrnández-Aburto
Universidad Nacional Autónoma de México
José G. Fernández-Trincado
Universidad Catolica del Norte
Eduardo Zagala Lagunas
Universidad Autonoma de Baja California
Leticia Carigi
Universidad Nacional Autónoma de México
J. E. Méndez-Delgado
Universidad Nacional Autónoma de México
Marina Kounkel
University of North Florida
Javier Serna
University of Oklahoma
Richard R. Lane
Universidad Bernardo O'Higgins
Keivan G. Stassun
Vanderbilt University
Sandro Villanova
Universidad Andrés Bello
Jinyoung Serena Kim
University of Arizona
S. J. Wolk
Harvard-Smithsonian Center for Astrophysics
Guy S. Stringfellow
University of Colorado
Jonathan Tan
Chalmers, Space, Earth and Environment
University of Virginia
A. Roman-Lopes
University of La Serena
Bárbara Rojas-Ayala
Universidad de Tarapacá
Rakesh Pandey
Universidad Nacional Autónoma de México
Monthly Notices of the Royal Astronomical Society
00358711 (ISSN) 13652966 (eISSN)
Vol. 543 1 420-434Subject Categories (SSIF 2025)
Astronomy, Astrophysics, and Cosmology
DOI
10.1093/mnras/staf1445