X-ray spectroscopy of the active giant βCeti: the SAX LECS view

We present an X-ray observation of the active giant β Cet, performedwith the LowEnergy Concentrator Spectrometer (LECS) on-board the SAX satellite. The resulting X-ray spectrum is well fit by an optically-thin plasma model with two discrete temperatures, and the inferred coronal metallicity is compatible both with the abundances derived from a re-analysis of the ASCA SIS spectrum of the same object, adopting the same plasma emission code (mekal), and with accurate photospheric abundances recently reported in the literature. The remarkable similarity between the X-ray spectrum of β Cet and the one of the active binary Capella, also observed by SAX, rises again the issue of how some putative He-burning clump giants, like β Cet, manage to retain (or regain) a relatively high X-ray activity level. Some implications of the new Hipparcos parallaxes, relevant for the coronal properties of β Cet and the Hyades giants, are also discussed.