| Full text | |
| Author(s): |
Miret-Roig, N.
;
Galli, P. A. B.
;
Olivares, J.
;
Bouy, H.
;
Alves, J.
;
Barrado, D.
Total Authors: 6
|
| Document type: | Journal article |
| Source: | Astronomy & Astrophysics; v. 667, p. 13-pg., 2022-11-23. |
| Abstract | |
Context. Understanding how star formation begins and propagates through molecular clouds is a fundamental but still open question. One major difficulty in addressing this question is the lack of precise 3D kinematics and age information for young stellar populations. Thanks to astrometry provided by Gaia, large spectroscopic surveys, and improved age-dating methods, this picture is changing. Aims. We aim to study spatial and kinematic substructures of the region encompassed by the Upper Scorpius and Ophiuchus star forming regions. We want to determine dynamical traceback ages and study the star formation history (SFH) of the complex. Methods. We combined our spectroscopic observations with spectra in public archives and large radial velocity surveys to obtain a precise radial velocity sample to complement the Gaia astrometry. We used a Gaussian Mixture Model to identify different kinematic structures in the 6D space of positions and velocities. We applied an orbital traceback analysis to estimate a dynamical traceback age for each group and determine the place where it was born. Results. We identified seven different groups in this region. Four groups (nu Sco, beta Sco, sigma Sco and delta Sco) are part of Upper Scorpius, two groups (rho Oph and alpha Sco) are in Ophiuchus, and another group (pi Sco) is a nearby young population. We found an age gradient from the rho Oph group (the youngest) to the delta Sco group (less than or similar to 5 Myr), showing that star formation has been a sequential process for the past 5 Myr. Our traceback analysis shows that Upper Scorpius and rho Oph groups share a common origin. The closer group of pi Sco is probably older, and the traceback analysis suggests that this group and the alpha Sco group have different origins, likely related to other associations in the Sco-Cen complex. Conclusions. Our study shows that this region has a complex SFH that goes beyond the current formation scenario, and is likely a result of stellar feedback from massive stars, supernova explosions, and dynamic interactions between stellar groups and the molecular gas. In particular, we speculate that photoionisation from the massive delta Sco star could have triggered star formation first in the beta Sco group and then in the nu Sco group. The perturbations of stellar orbits due to stellar feedback and dynamical interactions could also be responsible for the 1-3 Myr difference that we found between dynamical traceback ages and isochronal ages. (AU) | |
| FAPESP's process: | 20/12518-8 - Dynamics and evolution of Young Stellar Clusters (DYSC) |
| Grantee: | Phillip Andreas Brenner Galli |
| Support Opportunities: | Research Grants - Young Investigators Grants |
| FAPESP's process: | 21/11778-9 - Dynamics and evolution of young stellar clusters (DYSC) |
| Grantee: | Phillip Andreas Brenner Galli |
| Support Opportunities: | Scholarships in Brazil - Young Researchers |