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Persistent Transition Region Emission in Very Low Mass Stars

Published online by Cambridge University Press:  26 May 2016

Suzanne L. Hawley  and
Christopher M. Johns-Krull
Suzanne L. Hawley
Affiliation:
University of Washington, Department of Astronomy, Box 351580, Seattle, WA 98195, USA
Christopher M. Johns-Krull
Affiliation:
Department of Physics & Astronomy, 6100 Main St., Rice University, Houston, Texas, 77005, USA

Abstract

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We have obtained HST/STIS time series observations of active, very low mass stars of spectral types M7-M9. The observations comprise 15 consecutive exposures on each of the stars VB 8, VB 10, and LHS 2065. Emission is present in several transition region lines including Si IV, C IV and He II. The emission appears to be variable between exposures, but is always observed. A strong flare was observed in one exposure on VB 10. Our results suggest that active, very low-mass stars maintain a persistent quiescent chromosphere and transition region that is similar to those observed in active, earlier type M dwarfs. This contradicts the currently popular idea that very low mass stars exhibit only relatively strong flares and no quiescent emission.

Type
Part 6: Low Mass Stellar Magnetic Activity and Evolution
Information
Symposium - International Astronomical Union , Volume 219: Stars as Suns : Activity, Evolution and Planets , 2004 , pp. 306 - 310
Copyright
Copyright © Astronomical Society of the Pacific 2004 

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