Antisolar differential rotation of slowly rotating cool stars
- Rotating stellar convection transports angular momentum towards the equator, generating the characteristic equatorial acceleration of the solar rotation while the radial flux of angular momentum is always inwards. New numerical box simulations for the meridional cross-correlation < u(theta)u(phi)>, however, reveal the angular momentum transport towards the poles for slow rotation and towards the equator for fast rotation. The explanation is that for slow rotation a negative radial gradient of the angular velocity always appears, which in combination with a so-far neglected rotation-induced off-diagonal eddy viscosity term nu(perpendicular to) provides "antisolar rotation" laws with a decelerated equator Similarly, the simulations provided positive values for the rotation-induced correlation < u(r)u(theta)>, which is relevant for the resulting latitudinal temperature profiles (cool or warm poles) for slow rotation and negative values for fast rotation. Observations of the differential rotation of slowly rotating stars will thereforeRotating stellar convection transports angular momentum towards the equator, generating the characteristic equatorial acceleration of the solar rotation while the radial flux of angular momentum is always inwards. New numerical box simulations for the meridional cross-correlation < u(theta)u(phi)>, however, reveal the angular momentum transport towards the poles for slow rotation and towards the equator for fast rotation. The explanation is that for slow rotation a negative radial gradient of the angular velocity always appears, which in combination with a so-far neglected rotation-induced off-diagonal eddy viscosity term nu(perpendicular to) provides "antisolar rotation" laws with a decelerated equator Similarly, the simulations provided positive values for the rotation-induced correlation < u(r)u(theta)>, which is relevant for the resulting latitudinal temperature profiles (cool or warm poles) for slow rotation and negative values for fast rotation. Observations of the differential rotation of slowly rotating stars will therefore lead to a better understanding of the actual stress-strain relation, the heat transport, and the underlying model of the rotating convection.…
| Author details: | Günther RüdigerORCiDGND, Manfred KükerORCiD, P. J. Kapyla, Klaus G. StrassmeierORCiDGND |
|---|---|
| DOI: | https://doi.org/10.1051/0004-6361/201935280 |
| ISSN: | 1432-0746 |
| Title of parent work (English): | Astronomy and astrophysics : an international weekly journal |
| Publisher: | EDP Sciences |
| Place of publishing: | Les Ulis |
| Publication type: | Article |
| Language: | English |
| Date of first publication: | 2019/07/23 |
| Publication year: | 2019 |
| Release date: | 2020/11/04 |
| Tag: | convection; stars: rotation; stars: solar-type; turbulence |
| Volume: | 630 |
| Number of pages: | 9 |
| Funding institution: | Deutsche Forschungsgemeinschaft Heisenberg programme [KA 4825/1-1]; Academy of Finland ReSoLVE Centre of Excellence [307411] |
| Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
| DDC classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
| Peer review: | Referiert |
| Publishing method: | Open Access |
| Open Access / Bronze Open-Access |
