Rotational evolution of solar-type protostars during the star-disk interaction phase
Journal
Date Issued
2019
Author(s)
Abstract
The early pre-main sequence phase during which they are still likely
surrounded by an accretion disk represents a puzzling stage of the rotational
evolution of solar-mass stars. While they are still accreting and contracting
they do not seem to spin-up substantially. It is usually assumed that the
magnetospheric star-disk interaction tends to maintain the stellar rotation
period constant (disklocking), but this hypothesis has never been thoroughly
verified. Our aim is to investigate the impact of the star-disk interaction
mechanism on the stellar spin evolution during the accreting pre-main sequence
phases. We devise a model for the torques acting onto the stellar envelope
based on studies of stellar winds and develop a new prescription for the
star-disk coupling grounded on numerical simulations of star-disk interaction
and magnetospheric ejections. We then use this torque model to follow the
long-term evolution of the stellar rotation. Magnetospheric ejections and
accretion powered stellar winds play an important role in the spin evolution of
solar-type stars. However, kG dipolar magnetic fields are not uncommon but not
ubiquitous. Besides, it is unclear how massive stellar winds can be powered,
while numerical models of the propeller regime display a strong variability
that has no observational confirmation. Better observational statistics and
more realistic models could contribute to soften our calculations'
requirements.
Volume
632
Start page
A6
Issn Identifier
0004-6361
Ads BibCode
2019A&A...632A...6G
Rights
open.access
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