The APOGEE-2 Survey of the Orion Star-forming Complex. II. Six-dimensional Structure

Kounkel, M.; Covey, Kevin; Suárez, Genaro; Román-Zúñiga, Carlos; Hernandez, Jesus; Stassun, Keivan; Jaehnig, Karl O.; Feigelson, Eric D.; Peña Ramírez, Karla; Roman-Lopes, Alexandre et al.
Bibliographical reference

The Astronomical Journal, Volume 156, Issue 3, article id. 84, 22 pp. (2018).

Advertised on:
9
2018
Description
We present an analysis of spectroscopic and astrometric data from APOGEE-2 and Gaia DR2 to identify structures toward the Orion Complex. By applying a hierarchical clustering algorithm to the six-dimensional stellar data, we identify spatially and/or kinematically distinct groups of young stellar objects with ages ranging from 1 to 12 Myr. We also investigate the star-forming history within the Orion Complex and identify peculiar subclusters. With this method we reconstruct the older populations in the regions that are currently largely devoid of molecular gas, such as Orion C (which includes the σ Ori cluster) and Orion D (the population that traces Ori OB1a, OB1b, and Orion X). We report on the distances, kinematics, and ages of the groups within the Complex. The Orion D group is in the process of expanding. On the other hand, Orion B is still in the process of contraction. In λ Ori the proper motions are consistent with a radial expansion due to an explosion from a supernova; the traceback age from the expansion exceeds the age of the youngest stars formed near the outer edges of the region, and their formation would have been triggered when they were halfway from the cluster center to their current positions. We also present a comparison between the parallax and proper-motion solutions obtained by Gaia DR2 and those obtained toward star-forming regions by the Very Long Baseline Array.
Related projects
Project Image
Nucleosynthesis and molecular processes in the late stages of Stellar Evolution

Low- to intermediate-mass (M < 8 solar masses, Ms) stars represent the majority of stars in the Cosmos. They finish their lives on the Asymptotic Giant Branch (AGB) - just before they form planetary nebulae (PNe) - where they experience complex nucleosynthetic and molecular processes. AGB stars are important contributors to the enrichment of the

Domingo Aníbal
García Hernández
Type