Modeling the rotation history of solar-type stars is an outstanding problem in modern astrophysics. One of the main challenges is to explain the dispersion in the distribution of stellar rotation rate for young stars. Previous works have advocated diverse mechanisms to explain the presence of fast rotators (FRs) and also of slow rotators (SRs). For instance, dynamo saturation can limit the stellar spin-down and explain the presence of FRs but does not produce enough SRs. Here, we present a new model that can account for the presence of both types of rotators by incorporating fluctuations in the angular momentum loss. This renders the spin-down problem probabilistic in nature, some stars experiencing more braking on average than others. We show that random fluctuations in the loss of angular momentum enhance the population of both FR and SR compared to the deterministic cases (with a linear dynamo prescription or with dynamo saturation). The stochastic angular momentum loss thus provides an alternative physical mechanism to that of a saturated dynamo, with an even better agreement with observations.
Bibliographical noteCopyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders.
- Stars: Evolution
- Stars: Interiors
- Stars: Rotation
ASJC Scopus subject areas
- Space and Planetary Science
- Astronomy and Astrophysics
- Nuclear and High Energy Physics