Bibcode
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; Da Rio, Nicola; Stringfellow, Guy S.; Kim, J. Serena; Borissova, Jura; Fernández-Trincado, José G.; Burgasser, Adam; García-Hernández, D. A.; Zamora, O.; Pan, Kaike; Nitschelm, Christian
Bibliographical reference
The Astronomical Journal, Volume 156, Issue 3, article id. 84, 22 pp. (2018).
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9
2018
Citations
261
Refereed citations
237
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.
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García Hernández