Stellar magnetism: empirical trends with age and rotation

By A. Vidotto, S. G. Gregory, M. Jardine, J. Donati, P. Petit, J. Morin, C. Folsom, J. Bouvier, A. Cameron, G. Hussain and 5 more. 2014

311 citations recorded by the source corpus.

We investigate how the observed large-scale surface magnetic fields of low-mass stars (∼0.1– 2M� ), reconstructed through Zeeman–Doppler imaging, vary with age t, rotation and Xray emission. Our sample consists of 104 magnetic maps of 73 stars, from accreting premain sequence to main-sequence objects (1Myr t 10 Gyr). For non-accreting dwarfs we empirically find that the unsigned average large-scale surface field is related to age as t −0.655 ± 0.045 . This relation has a similar dependence to that identified by Skumanich, used as the basis for gyrochronology. Likewise, our relation could be used as an age-dating method (‘magnetochronology’). The trends with rotation we find for the large-scale stellar magnetism are consistent with the trends found from Zeeman broadening measurements (sensitive to large- and small-scale fields). These similarities indicate that the fields recovered from both techniques are coupled to each other, suggesting that small- and large-scale fields could share the same dynamo field generation processes. For the accreting objects, fewer statistically significant relations are found, with one being a correlation between the unsigned magnetic flux and rotation period. We attribute this to a signature of star–disc interaction, rather than being driven by the dynamo.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/a23410bc79762331c8354f254933aee9195226a9

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In Astronomy and Astrophysics

1. M. Gudel
2. J. Bouvier
3. Colin P. Johnstone
4. H. Lammer
5. J. Owen
6. T. Lüftinger
7. I. Brott
8. Lin Tu

Citations in the corpus

• THE MASS-DEPENDENCE OF ANGULAR MOMENTUM EVOLUTION IN SUN-LIKE STARS (2014, background): “…indicators of magnetic activity (Noyes et al. 1984a; Reiners et al. 2009; Pizzolato et al. 2003; Mamajek & Hillenbrand 2008; Wright et al. 2011; Vidotto et al. 2014), as well as theoretical models for magnetic field generation (Durney & Latour 1978; Noyes et al. 1984b; Baliunas et al. 1996;…”
• Improved angular momentum evolution model for solar-like stars II. Exploring the mass dependence (2015, unknown): “This has obvious consequences on stellar evolution (Charbonnel et al. 2013), the depletion of light elements such as Lithium (Bouvier 2008; Eggenberger et al. 2012a), and the type of magnetic dynamos that may be instrumental in young solar-type stars (Vidotto et al. 2014a).”
• Stellar winds on the main-sequence - II. The evolution of rotation and winds (2015, methodology): “, in excellent agreement with the results of Vidotto et al. (2014b) (the apparent perfect agreement is of course coincidental).”
• The Extreme Ultraviolet and X-Ray Sun in Time: High-Energy Evolutionary Tracks of a Solar-Like Star (2015, methodology): “For Bdip, we use the scaling law derived by Vidotto et al. (2014) of Bdip ∝ Ro−1.32.”
• Rotation, differential rotation, and gyrochronology of active Kepler stars (2015, methodology): “Furthermore, Vidotto et al. (2014) found a correlation between the average large-scale magnetic field strength and the stellar age according to 〈|BV |〉 ∝ t−0.655 similar to Skumanich’s law, calling this method magnetochronology.”