MAGNETIC BRAKING FORMULATION FOR SUN-LIKE STARS: DEPENDENCE ON DIPOLE FIELD STRENGTH AND ROTATION RATE

By S. Matt, K. Macgregor, M. Pinsonneault, T. Greene. 2012

144 citations recorded by the source corpus.

We use two-dimensional axisymmetric magnetohydrodynamic simulations to compute steady-state solutions for solar-like stellar winds from rotating stars with dipolar magnetic fields. Our parameter study includes 50 simulations covering a wide range of relative magnetic field strengths and rotation rates, extending from the slow- and approaching the fast-magnetic-rotator regimes. Using the simulations to compute the angular momentum loss, we derive a semi-analytic formulation for the external torque on the star that fits all of the simulations to a precision of a few percent. This formula provides a simple method for computing the magnetic braking of Sun-like stars due to magnetized stellar winds, which properly includes the dependence on the strength of the magnetic field, mass loss rate, stellar radius, surface gravity, and spin rate, and which is valid for both slow and fast rotators.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/10ebc3cb25b000886f35c604c0f9129fe2dd36f6

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

1. M. Gudel
2. F. Gallet
3. Colin P. Johnstone
4. Suzanne Aigrain
5. J. Bouvier
6. A. McQuillan
7. H. Lammer
8. T. Mazeh

Citations in the corpus

• Stellar winds on the main-sequence - II. The evolution of rotation and winds (2015, methodology): “At a given stellar mass and radius, the torque formula derived by Matt et al. (2012) approximately reduces to τw ∝ B0.”
• ROTATION PERIODS OF 34,030 KEPLER MAIN-SEQUENCE STARS: THE FULL AUTOCORRELATION SAMPLE (2014, background): “In recent years there has also been considerable work towards understanding and modeling the underlying physics behind gyrochronology (Reiners & Mohanty 2012; Matt et al. 2012; Gallet & Bouvier 2013, and references therein).”
• Improved angular momentum evolution model for solar-like stars (2013, methodology): “…not recent (see, Edwards et al. 1993; Bouvier et al. 1993; Rebull et al. 2004), many theoretical advances have been made in the last years highlighting the impact of the accretion/ejection phenomenon on the angular momentum evolution of young suns (e.g., Matt et al. 2012b; Zanni & Ferreira 2013).”
• Improved angular momentum evolution model for solar-like stars II. Exploring the mass dependence (2015, unknown): “The latter is obtained from Matt et al. (2012a) as where B p is the surface strength of the dipole magnetic field at the stellar equator, v esc = √ 2 GM ∗ / R ∗ is the escape velocity, and m = 0 .”
• THE MASS-DEPENDENCE OF ANGULAR MOMENTUM EVOLUTION IN SUN-LIKE STARS (2014, background): “…theoretical developments of how magnetized stellar winds remove angular momentum (Schatzman 1962; Mestel 1968; Weber & Davis 1967; Kawaler 1988; Matt et al. 2012); models for the evolution of stellar spin rate in time (e.g., MacGregor & Brenner 1991; Denissenkov et al. 2010; Scholz et al.…”
• The Extreme Ultraviolet and X-Ray Sun in Time: High-Energy Evolutionary Tracks of a Solar-Like Star (2015, methodology): “For the wind torque, we use the formula derived by Matt et al. (2012) which relates the wind torque to stellar parameters, the star’s dipole field strength,Bdip, and the wind mass loss rate,̇M⋆.”