The spin evolution of stars born in clusters
Abstract
While most spin evolution models consider stars that form and evolve in isolation, the vast majority of observed young stars are located in clustered environments. Towards reducing this discrepancy, in this talk, we will show the results of a spin evolution model that considers the influence of open clusters' early environments on the spin evolution of low mass stars. In particular, we looked at how stellar density and the presence of massive stars shape the local far-ultraviolet radiation fields of clusters, influencing the dissipation timescales of circumstellar disks due to external photoevaporation. Environmentally dependent disk-dissipation timescales directly impact the duration of the star-disk-interaction phase, during which stars are expected to exchange angular momentum with their disk. By modelling the spin evolution of the low mass population of entire clusters with diverse environments, we will illustrate how these environments can contribute to shaping clusters' rotational distributions, with the feedback from massive stars playing a crucial role in explaining the mass dependence of rotation observed in the period-mass distributions of young regions like NGC 2264 and Upper Sco. By inducing an earlier start of the pre-main-sequence spin-up phase in stars evolving under high far-ultraviolet environments, the presence of high-mass stars can skew the spin-rate distribution of surrounding stars towards fast-rotation, explaining the excess of fast-rotating stars in the open cluster h Per. Environmental fingerprints on cluster's period-mass distributions should be observable at ages as early as 3 Myrs and remain visible until the stars' spin starts following the Skumanich spin-down. This suggests that the rotation of stars prior to the Skumanich spin-down phase could be used to trace their primordial ultraviolet irradiation, offering a potential method to connect planetary systems around stars with early-MS ages to their birth environment.
- Publication:
-
The 21st Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun
- Pub Date:
- December 2022
- DOI:
- 10.5281/zenodo.7590777
- Bibcode:
- 2022csss.confE.189R
- Keywords:
-
- Spin Evolution;
- Low Mass Stars;
- Star-disk systems;
- disk-locking;
- star clusters;
- Zenodo community cs21