\journalname
Astronomy&AstrophysicsReview
The mass-radius diagram.
Fig. \ref{logRlogM} shows the mass-radius diagram for the stars in Table \ref{tableMR}; note that the error bars are smaller than the plotted symbols. Relative to A91, the mass range has been expanded both at the higher (V3903 Sgr) and the lower end (CM Dra), and the diagram is, of course, much better populated than before. For the first time it includes an extragalactic binary, the two-giant system OGLE-051019.64-685812.3 in the Large Magellanic Cloud (here called OGLE 051019 for short). It is noteworthy, however, that the two stars in OGLE 051019 are the only new bona fide red giants since the two in A91 (TZ For A and AI Phe A). The large range in radius for a given mass clearly shows the effect of stellar evolution up through the main-sequence band, which in this diagram moves a star up along a vertical line as it evolves, if no significant mass loss occurs.