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| Paper: |
Stellar Rotation in the Hyades and Praesepe: Gyrochronology and Braking Timescale |
| Volume: |
448, 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun |
| Page: |
841 |
| Authors: |
Delorme, P.; Cameron, A. C.; Hebb, L.; Rostron, J.; Lister, T. A.; Norton, A. J.; Pollacco, D.; West, R. G. |
| Abstract: |
We present the results of photometric surveys for stellar rotation
in the Hyades and in Praesepe, using data obtained as part of the
SuperWASP exoplanetary transit-search programme. We determined
accurate rotation periods for more than 120 sources whose cluster
membership was confirmed by common proper motion and
colour-magnitude fits to the clusters' isochrones. This allowed us to
determine the effect of magnetic braking on a wide range of
spectral types for expected ages of ∼600 Myr for the Hyades and
Praesepe. Both clusters show a tight and nearly linear relation
between J–Ks colour and rotation period in the F, G and K spectral
range. This confirms that loss of angular momentum was significant
enough that stars with strongly different initial rotation rates have
converged to the same rotation period for a given mass, by
the age of Hyades and Praesepe. In the case of the Hyades our
colour-period sequence extends well into the M dwarf regime and
shows a steep increase in the scatter of the colour-period relation, with
identification of numerous rapid rotators from
∼0.5M☉ down to the lowest masses probed by our survey
(∼0.25M☉).
This provides crucial constraints on the rotational braking timescales
and further clears the way to use gyrochronology as an accurate age
measurement tool for main-sequence stars. |
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