On the possibility of using metal unblanketed model atmospheres for analysis of population II stars |
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| Authors: | M Moretti L Rossi |
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| Institution: | (1) Laboratorio Astrofisica Spaziale, CNR, Frascati, Roma, Italy |
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| Abstract: | A comparison between model atmosphere grids with and without metal blanketing has been performed in the low-temperature range (T
eff=6000 K to 10000 K) and for different metal contents (logA=0, –1, –2;A=scaled solar abundance). ForA 10–1 andT
eff 7000 K, the Johnson colour indicesU-B andB-V, together with the Strömgrenu-b, b-y and the bolometric correction (BC) are little affected by metal blanketing ( mag<0
.
m
04). On the other hand, the trend of the physical quantities and them
1 andc
1 colour indices reflect the inadequateness of the models even withA=10–2 andT
eff=9500 K, where hydrogen line blanketing is expected to dominate. This fact discourages once and for all the use of metal unblanketed atmospheres other than for comparison of colour indices or the calculation of bolometric corrections for Population II A-F spectral types. |
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| Keywords: | |
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