Accretion-powered Stellar Winds as a Solution to the Stellar Angular Momentum Problem

By S. Matt, R. Pudritz. 2005

259 citations recorded by the source corpus.

We compare the angular momentum extracted by a wind from a pre-main-sequence star to the torques arising from the interaction between the star and its Keplerian accretion disk. We find that the wind alone can counteract the spin-up torque from mass accretion, solving the mystery of why accreting pre-main-sequence stars are observed to spin at less than 10% of breakup speed, provided that the mass outflow rate in the stellar winds is ~10% of the accretion rate. We suggest that such massive winds will be driven by some fraction ϵ of the accretion power. For observationally constrained typical parameters of classical T Tauri stars, ϵ needs to be between a few and a few tens of percent. In this scenario, efficient braking of the star will terminate simultaneously with accretion, as is usually assumed to explain the rotation velocities of stars in young clusters.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/edd3f6c8299c064dec8368e216a2c6bf9411a958

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In Astronomy and Astrophysics

1. G. Herczeg
2. L. Hillenbrand
3. K. Luhman
4. D. Charbonneau
5. J. Bouvier
6. F. Gallet
7. N. Calvet
8. M. Romanova

Citations in the corpus

• The Magnetic Fields of Classical T Tauri Stars (2007, background): “It should be noted, however, that Matt & Pudritz (2004, 2005a) have recently asserted that the spindown torque produced on the star in magnetospheric accretion models may be up to an order of magnitude lower than most pre- vious investigators have calculated.”
• Accretion onto Pre-Main-Sequence Stars (2016, background): “A potentially attractive aspect of such a wind is that it would be magnetically coupled directly to the stellar surface, and thus might help spin down the star (Matt & Pudritz 2005, Matt et al. 2012); but whether this mechanism really can drive sufficiently large outflows is not clear.”
• Accretion-powered Stellar Winds. II. Numerical Solutions for Stellar Wind Torques (2008, methodology): “The Fiducial Case We start by presenting the results of our stellar wind simulation for parameters with values that represent a “typical” T Tauri star and follow the fiducial values of Paper I and Matt & Pudritz (2005b).”
• Which jet launching mechanism(s) in T Tauri stars (2006, background): “This would be expected to produce a correlation between accretion and ejection signatures, leading to ”accretion-powered stellar winds” (Matt & Pudritz 2005).”
• Improved angular momentum evolution model for solar-like stars (2013, background): “More recently, accretionpowered stellar winds have been proposed as a way to remove from the central star the excess of angular momentum gained from disk accretion (Matt & Pudritz 2005, 2008a,b).”
• Episodic accretion on to strongly magnetic stars (2010, background): “The open field lines at larger radii could launch a disc wind which would provide an additional sink for angular momentum and somewhat change the structure of the disc (e.g. Matt & Pudritz 2005).”
• Launching of conical winds and axial jets from the disc–magnetosphere boundary: axisymmetric and 3D simulations (2009, background): “The existence of powerful stellar winds was suggested by Matt & Pudritz (2005, 2008) in order to explain the loss of angular momentum by young stars.”
• Lithium depletion and the rotational history of exoplanet host stars (2008, result): “This ”disk-locking” assumption is supported by both observational evidence (Rebull et al. 2006; Cieza & Baliber 2007) and MHD models of the star-disk interaction (e.g. Matt & Pudritz 2005; Romanova et al. 2007).”
• On the formation of Hα line emission around classical T Tauri stars (2006, methodology): “In reality, however, the two types of winds may be present in the same object, in a similar fashion to that seen in the models of Drew, Proga & Stone (1998) and Matt & Pudritz (2005).”
• Magnetic Fields of Nondegenerate Stars (2009, background): “…and simulations fail to confirm that the magnetic torque from the accretion disc is strong enough to spin the star down as observations suggest (e.g., Bessolaz et al. 2008); a braking contribution from an accretion-powered magnetised stellar wind may help solving the problem (Matt & Pudritz 2005).”
• EVIDENCE OF POSSIBLE SPIN–ORBIT MISALIGNMENT ALONG THE LINE OF SIGHT IN TRANSITING EXOPLANET SYSTEMS (2010, background): “Two classes of physical models have been proposed to explain this early-time behavior: magnetic breaking by protostellar disks (e.g. Koenigl 1991; Shu et al. 1994; Collier Cameron et al. 1995) and accretion-driven stellar winds (e.g. Matt & Pudritz 2005).”
• ON THE ANGULAR MOMENTUM EVOLUTION OF FULLY CONVECTIVE STARS: ROTATION PERIODS FOR FIELD M-DWARFS FROM THE MEarth TRANSIT SURVEY (2010, background): “…is counteracted by angular momentum losses, which are thought to be related to the star-disc interaction at early times (e.g. accretiondriven winds; Matt & Pudritz 2005, or “disc locking”; Königl 1991; Collier Cameron, Campbell & Quaintrell 1995), and stellar winds at late times, particularly…”
• Magnetospheric accretion-ejection processes in the classical T Tauri star AA Tauri (2006, background): “Note that this simple geometric interpretation favors inner disk winds (e.g. Alencar et al. 2005) over accretion driven stellar winds (e.g. Matt & Pudritz 2005).”
• Improved angular momentum evolution model for solar-like stars II. Exploring the mass dependence (2015, unknown): “…Matt et al. 2010), the loss of angular momentum through powerful stellar winds on the early main sequence (MS; Weber & Davis 1967; Kawaler 1988; Matt & Pudritz 2005a; Vidotto et al. 2011, 2014b; Zanni & Ferreira 2011; Cranmer & Saar 2011; Matt et al. 2012a,b; Reiners & Mohanty 2012; Réville et…”
• MHD simulations of accretion onto a dipolar magnetosphere - II. Magnetospheric ejections and stellar spin-down (2012, methodology): “…has been shown that the efficiency of the Ghosh & Lamb mechanism is drastically reduced because of the limited size of the connected magnetosphere (Matt & Pudritz 2005a) and the dilution of the poloidal field beyond the corotation radius (Agapitou & Papaloizou 2000; Zanni & Ferreira 2009,…”
• Probing T Tauri Accretion and Outflow with 1 Micron Spectroscopy (2006, background): “This allows for the possibility that magnetized stellar winds rather than magnetospheric disk locking may be the means by which accreting stars spin down to rotational velocities well below break-up (Matt & Pudritz 2005; von Rekowski & Brandenburg 2006; Romanova et al. 2005).”
• The Habitability of Planets Orbiting M-dwarf Stars (2016, background): “…the rotation rates observed in young clusters: Kelvin-Helmholtz contraction and late-stage accretion spin the star up, while angular momentum is lost from interaction with the disk (Hartmann & Stauffer, 1989; Bouvier et al., 1997; Koenigl, 1991; Collier Cameron et al., 1995; Matt & Pudritz, 2005).”
• MAGNETIC BRAKING FORMULATION FOR SUN-LIKE STARS: DEPENDENCE ON DIPOLE FIELD STRENGTH AND ROTATION RATE (2012, background): “For example, during the premain-sequence phase, there is not yet a comprehensive picture that explains the observed wide range of rotation rates, nor the fact that a large fraction of stars rotate relatively slowly (e.g., Herbst et al. 2007; Irwin & Bouvier 2009; Matt & Pudritz 2005b,a).”