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The mass (M) of a star can be evaluated from its spectroscopically determinedeffective temperature (T _eff) and metallicity ([Fe/H]) along with theluminosity (L; derived from parallax), while comparing them with grids oftheoretical evolutionary tracks. It has been argued, however, that such atrack-based mass (M_trk) may tend to be overestimated for the case of redgiants. Meanwhile, there is an alternative approach of evaluating mass (M_gLT)directly from surface gravity (g), L, and T_eff. The practical reliability ofM_gLT was examined for ~100 benchmark giants in the Kepler field, for whichatmospheric parameters are already determined and the reliable mass (M_seis)along with the evolutionary status are known from asteroseismology. Inaddition, similar check was also made for the accuracy of M_trk for comparison.It turned out that, while a reasonable correlation is seen between M_gLT andM_seis almost irrespective of the stellar property, its precision is ratherinsufficient because log(M_gLT/M_seis) distributes rather widely within~+/-0.2--0.3dex. In contrast, the reliability of M_trk was found to depend onthe evolutionary status. Although M_trk and M_seis are satisfactorilyconsistent with each other (typical dispersion of log(M_trk}/M_seis) is within~+/-0.1dex) for H-burning red giants as well as He-burning 2nd clump giants ofhigher mass, M_trk tends to be considerably overestimated as compared to M_seisby up to ~<0.4~dex for He-burning 1st clump giants of lower mass. Accordingly,M_gLT and M_trk are complementary with each other in terms of theircharacteristic merit and demerit.

Mass evaluation for red giant stars based on the spectroscopically determined atmospheric parameters