The Search for Super-saturation in Chromospheric Emission

D.J. Christian, Michail Mathioudakis, T. Arias, M. Jardine, David Jess

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4 Citations (Scopus)


We investigate if the super-saturation phenomenon observed at X-ray wavelengths for the corona exists in the chromosphere for rapidly rotating late-type stars. Moderate resolution optical spectra of fast-rotating EUV- and X-ray-selected late-type stars were obtained. Stars in a Per were observed in the northern hemisphere with the Isaac Newton 2.5 m telescope and Intermediate Dispersion Spectrograph. Selected objects from IC 2391 and IC 2602 were observed in the southern hemisphere with the Blanco 4 m telescope and R-C spectrograph at CTIO. Ca II H and K fluxes were measured for all stars in our sample. We find the saturation level for Ca II K at log (L CaK/L bol) = -4.08. The Ca II K flux does not show a decrease as a function of increased rotational velocity or smaller Rossby number as observed in the X-ray. This lack of "super-saturation" supports the idea of coronal stripping as the cause of saturation and super-saturation in stellar chromospheres and coronae, but the detailed underlying mechanism is still under investigation.
Original languageEnglish
Article number164
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 10 Sep 2011

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics


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