Prominence formation and ejection in cool stars
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The observational signatures of prominences have been detected in single and binary G and K type stars for many years now, but recently this has been extended to the M dwarf regime. Prominences carry away both mass and angular momentum when they are ejected and the impact of this mass on any orbiting planets may be important for the evolution of exoplanetary atmospheres. By means of the classification used in the massive star community, that involves knowledge of two parameters (the co-rotation and Alfvén radii, rK and rA), we have determined which cool stars could support prominences. From a model of mechanical support, we have determined that the prominence mass mp/M*=(EM/EG)(r*/rK)2F where EMB2⋆r3⋆ and EG=GM2⋆/r⋆ are magnetic and gravitational energies and F is a geometric factor. Our calculated masses and ejection frequencies (typically 1016−1017g and 0.4 d, respectively) are consistent with observations and are sufficient to ensure that an exoplanet orbiting in the habitable zone of an M dwarf could suffer frequent impacts.
Villarreal D'Angelo , C S , Jardine , M M & See , W C V 2018 , ' Prominence formation and ejection in cool stars ' Monthly Notices of the Royal Astronomical Society: Letters , vol 475 , no. 1 , pp. 25-29 . DOI: 10.1093/mnrasl/slx206
Monthly Notices of the Royal Astronomical Society: Letters
© 2017, the Author(s). This work has been made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at https://doi.org/10.1093/mnrasl/slx206
DescriptionWe acknowledge STFC (ST/M001296/1) and H2020 (682393).
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