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| Paper: |
CA II K-line metallicity indicator for field RR Lyrae stars |
| Volume: |
13, The Formation and Evolution of Star Clusters |
| Page: |
556 |
| Authors: |
Clementini, Gisella; Tosi, Monica; Merighi, Roberto |
| Abstract: |
In order to check and, possibly, improve the Preston's Delta S calibration scale, CCD spectra have been obtained for 25 field RR Lyrae variables. Eleven of the program stars have values of (Fe/H) derived by Butler and Deming (1979) from the Fe II lines' strength. For them we find that the equivalent width of the Ca II K line is extremely well correlated to the (Fe/H) values, the best fit relation being: (Fe/H) = 0.43W(K) - 2.75 where W(K) is the equivalent width of the K line. We conclude that the use of the K line equivalent width is at present the best method to derive the (Fe/H) abundance of the RR Lyrae stars. |
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