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Flares on T Tauri stars

Published online by Cambridge University Press:  23 September 2016

G. F. Gahm
G. F. Gahm*
Affiliation:
Stockholm Observatory S-133 36 Saltsjöbaden Sweden

Abstract

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An overview of the characteristics of short-term light variability on T Tauri stars is given. The evidence of the occurrence of flares comes from observations mainly at X-ray energies and from patrole observations in the ultraviolet spectral region. From such observations some limits on the peak fluxes and total energies of the largest flare-like events can be set. In addition, the frequency of such events can be deduced for a number of stars. It is demonstrated that there appears to be a qualitative difference between powerful flare-like events on the weak-line T Tauri stars (NTTs) and those on strong-line stars (CTTs). While it appears that the concept of surface flares occurring on NTTs may be correct there is the evidence that the disk-stars in addition produce flare-like events of a different nature. These events could be related to processes occurring not on the stars but in their circumstellar environment, for instance in a circumstellar disk. We also point at observations that could be of importance in clarifying the cause of flare-like activity on T Tauri stars and also comment on how this activity changes with stellar age.

Type
II Flare Stars and Related Objects T Tauri Stars
Information
Symposium - International Astronomical Union , Volume 137: Flare Stars in Star Clusters, Association and Solar Vicinity , 1990 , pp. 193 - 207
Copyright
Copyright © Kluwer 1990 

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