The dependence of differential rotation on temperature and rotation
By J. Barnes, A. Cameron, J. Donati, David J. James, S. Marsden, P. Petit. 2004
205 citations recorded by the source corpus.
We use Doppler imaging techniques to determine the dependence of starspot rotation rates on latitude in an homogeneous sample of young, rapidly-rotating solar analogues. A solar-like differential rotation law is used, where the rot ation depends on sin 2 (θ), where θ is the stellar latitude. By including this term in the image rec onstruction process, using starspots as tracers, we are able to determine the magnitude of the shear over more than one rotation cycle. We also consider results from matched filter starspot tracking techniques, where individual starspot rotation rates are determined. In addition we have re-analysed published results and present a new measurement for the K3 dwarf, Speedy Mic. A total of 10 stars of spectral type G2 - M2 are considered. We fi nd a trend towards decreasing surface differential rotation with decreasing effective temperature. The implied approach to solid body rotation with increasing relative co nvection zone depth implies that the dynamo mechanism operating in low-mass stars may be substantially different from that in the Sun.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/80369d8f9c21ef64d18255c5be8b225aa07fafa1
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In Astronomy and Astrophysics
Citations in the corpus
- Magnetic activity in the photosphere of CoRoT-Exo-2a. Active longitudes and short-term spot cycle in (2008, background): “2 of Barnes et al. (2005) is about one order of magnitude greater, suggesting that the spots observed on CoRoT-Exo-2a are localized in a quite narrow latitude band or that our star has been observed in a state with a low degree of differential rotation (cf. Donati et al. 2003; Lanza 2006).”
- Large-scale magnetic topologies of late M dwarfs⋆ (2008, background): “Among cool stars, those with masses lower than about 0.35 M⊙ are fully-convective (e.g., Chabrier & Baraffe 1997), and therefore do not possess a tachocline; some observations further suggest that they rotate almost as rigid bodies (Barnes et al. 2005).”
- Rotation, differential rotation, and gyrochronology of active Kepler stars (2015, background): “We find good agreement with measurements from Barnes et al. (2005) claiming dΩ ∝ 〈Ω〉0.15±0.10, confirming the weak dependence of the absolute shear on the rotation rate.”
- From solar-like to antisolar differential rotation in cool stars (2013, background): “For main and pre-main sequence stars, observations of absolutesurface shear show some dependence on rotation period and effective temperature (Barnes et al. 2005; Ammler-von Eiff & Reiners 2012; Reinhold et al. 2013).”
- Starspots: A Key to the Stellar Dynamo (2005, methodology): “It was applied to a small sample of active G2–M2 dwarfs, all showing a solar type differential rotation (Petit et al., 2004; Barnes et al., 2005).”
- Can Superflares Occur on Our Sun (2012, background): “It should be noted that actual observations of differential rotation in late-type stars (Barnes et al. 2005; Reiners 2006) have revealed behavior different from that assumed here, i.e., the differential rotation decreases with decreasing surface temperature, and has a weaker dependence on the…”
- Toroidal versus poloidal magnetic fields in Sun-like stars: a rotation threshold (2008, background): “With a level of rotational shear about 2.3 times that of the Sun, HD 190771 is following nicely the mass-trend derived observationally by Barnes et al. (2005) for other rapidly rotating stars (note that, probably because of this observational bias towards high rotation rates, the solar differential…”
- Magnetic Field Generation in Fully Convective Rotating Spheres (2004, result): “This is consistent both with theory (Kitchatinov & Rüdiger 1999) and with observations showing only a weak dependence of surface differential rotation on stellar rotation for late type stars (Barnes et al. 2005), which are however not fully convective.”
- Large-scale magnetic topologies of early M dwarfs (2008, background): “Previous Doppler imaging studies of early-M dwarfs with very fast rotation (Ro ≃ 0.01) report that differential rotation is very small (Barnes et al. 2005); our study suggests that the situation may significantly differ in moderate rotators like those we considered.”