Astronomy and Astrophysics – Astronomy
Scientific paper
Jun 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005mnras.360..272l&link_type=abstract
Monthly Notices of the Royal Astronomical Society, Volume 360, Issue 1, pp. 272-281.
Astronomy and Astrophysics
Astronomy
23
Stars: Activity, Binaries: Close, Stars: Evolution, Stars: Rotation
Scientific paper
In a previous paper, using Eggleton's stellar evolution code, we have discussed the structure and evolution of low-mass W Ursae Majoris (W UMa) type contact binaries with angular momentum loss owing to gravitational radiation or magnetic braking. We find that gravitational radiation is almost insignificant for cyclic evolution of low-mass W UMa type systems, and it is possible for angular momentum to be lost from W UMa systems in a magnetic stellar wind. The weaker magnetic activity shown by observations in W UMa systems is likely caused by the lower mass of the convective envelopes in these systems than in similar but non-contact binaries. The spin angular momentum cannot be neglected at any time for W UMa type systems, especially for those with extreme mass ratios. The spin angular momenta of both components are included in this paper and they are found to have a significant influence on the cyclic evolution of W UMa systems. We investigate the influence of the energy transfer on the common convective envelopes of both components in detail. We find that the mass of the convective envelope of the primary in contact evolution is slightly more than that in poor thermal contact evolution, and that the mass of the convective envelope of the secondary in contact evolution is much less than that in poor thermal contact evolution. Meanwhile, the rate of angular momentum loss of W UMa type systems is much lower than that of poor thermal contact systems. This is indeed caused by the lower masses of the convective envelopes of the components in W UMa type systems. Although the models with angular momentum loss for W UMa systems exhibit cyclic evolution, they seem to show that a W UMa system cannot continue this type of cyclic evolution indefinitely, and it might coalesce into a fast-rotating star after about 1200 cycles of evolution (about 7.0 × 109 yr).
Han Zhanwen
Li Lifang
Zhang Fenghui
No associations
LandOfFree
Structure and evolution of low-mass W Ursae Majoris type systems - III. The effects of the spins of the stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Structure and evolution of low-mass W Ursae Majoris type systems - III. The effects of the spins of the stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structure and evolution of low-mass W Ursae Majoris type systems - III. The effects of the spins of the stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1409387