SIMBAD references

2011MNRAS.411.2099J - Mon. Not. R. Astron. Soc., 411, 2099-2112 (2011/March-1)

Investigating coronal saturation and supersaturation in fast-rotating M-dwarf stars.


Abstract (from CDS):

At fast rotation rates, the coronal activity of G- and K-type stars has been observed to `saturate' and then decline again at even faster rotation rates - a phenomenon dubbed `supersaturation'. In this paper, we investigate coronal activity in fast-rotating M-dwarfs using deep XMM-Newton observations of 97 low-mass stars of known rotation period in the young open cluster NGC 2547 and combine these with published X-ray surveys of low-mass field and cluster stars of known rotation period. Like G- and K-dwarfs, we find that M-dwarfs exhibit increasing coronal activity with decreasing Rossby number NR, the ratio of period to convective turnover time, and that activity saturates at LX/Lbol≃ 10–3 for log NR< -0.8. However, supersaturation is not convincingly displayed by M-dwarfs, despite the presence of many objects in our sample with log NR< -1.8, where supersaturation is observed to occur in higher mass stars. Instead, it appears that a short rotation period is the primary predictor of supersaturation; P ≤ 0.3 d for K-dwarfs and perhaps P ≤ 0.2 d for M-dwarfs. These observations favour the `centrifugal stripping' model for supersaturation, where coronal structures are forced open or become radiatively unstable as the Keplerian corotation radius moves inside the X-ray-emitting coronal volume.

Abstract Copyright: 2010 The Authors Monthly Notices of the Royal Astronomical Society2010 RAS

Journal keyword(s): stars: activity - stars: coronae - stars: rotation - open clusters and associations: individual: NGC 2547 - X-rays: stars

VizieR on-line data: <Available at CDS (J/MNRAS/411/2099): table1.dat table2.dat>

Simbad objects: 106

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