\beta Cet , 31 Com and \mu Vel represent the main stages through which late-type giants evolve during their lifetime ( the Hertzsprung gap ( 31 Com ) , the rapid braking zone ( \mu Vel ) and the core helium burning “ clump ” phase ( \beta Cet ) ) .
An analysis of their high resolution Chandra X-ray spectra reveals similar coronal characteristics in terms of both temperature structure and element abundances for the more evolved stars ( \mu Vel and \beta Cet ) with slight differences for the ‘ younger ’ giant ( 31 Com ) .
The coronal temperature structure of 31 Com is significantly hotter showing a clear peak while \beta Cet and \mu Vel show a plateau . \beta Cet and \mu Vel show evidence for a FIP effect in which coronae are depleted in high FIP elements relative to their photospheres by a factor of \sim 2 .
In contrast , 31 Com is characterized by a lack of FIP effect .
In other words , neither depletion nor enhancement relative to stellar photospheric values is found .
We conclude that the structural changes during the evolution of late-type giants could be responsible for the observed differences in coronal abundances and temperature structure .
In particular , the size of the convection zone coupled with the rotation rate seem obvious choices for playing a key role in determining coronal characteristics .