CDROM/AJ/V114/P0341 Type II Cepheids (Gonzalez & Lambert 1997) ================================================================================ Abundance Analyses of Type II Cepheids in Globular Clusters Guillermo Gonzalez and David L. Lambert <1997, AJ, 114, 341> =1997AJ....114..341G ================================================================================ Abstract: We have determined the photospheric compositions of five luminous F-G variables in globular clusters: V11 in M2, V42 in M5, V84 in M5, V2 in M10, and V17 in M28, three of which are classified as RV Tau variable stars. Unlike the recent findings that the photospheres of field RV Tau variables have been altered by a gas-dust separation process, none of these stars, except possibly V2 in M10, show such signs. We suggest that either a smaller carbon abundance in the photosphere of a globular cluster RV Tau star (compared to its field analogues) might be a factor in the gas-dust separation process due to the lack of sufficient carbon grain formation, or the stellar winds and their efficacy as dust-grain separators is influenced by the metallicity of the stellar envelope which, unlike the photosphere, is never subject to alteration by a dust-gas separation. Our analysis is most complete for V84, for which we have estimated the abundances of 19 chemical elements. Compared to the other giants in M5, this star displays a very large excess of Na and a deficit of O. This finding is consistent with a recently proposed mechanism of Na production in the ON-cycling region of metal-poor RGB stars. The value of [Al/Fe] for V84 is also high (also consistent with ON-cycling), but a comparison with the other cluster giants cannot be performed until Al is measured in their spectra. The s-process elements are not significantly enhanced in the atmosphere of V84 relative to the other cluster members. (c) 1997 American Astronomical Society. File Summary: -------------------------------------------------------------------------------- File Name Lrecl Records Explanations -------------------------------------------------------------------------------- table3.dat 46 53 Individual abundance results for V11 in M2 using the model atmospheres in Table 1 table4.dat 46 35 Individual abundance results for V42 in M5 using the model atmospheres in Table 1 table5.dat 56 100 Individual abundance results for V84 in M5 using the model atmospheres in Table 1 table6.dat 36 26 Individual abundance results for the 1992 June 17 spectrum of V2 in M10 using the model atmospheres listed in Table 1 table7.dat 36 51 Individual abundance results for the 1995 June 10 & 12 spectra of V17 in M28 using the model atmospheres listed in Table 1 table3.tex 74 81 AASTeX version of table3.dat table4.tex 72 66 AASTeX version of table4.dat table5.tex 72 145 AASTeX version of table5.dat table6.tex 75 52 AASTeX version of table6.dat table7.tex 77 83 AASTeX version of table7.dat -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Species Ion species 6-14 F9.2 0.1nm Lambda Wavelength 15-19 F5.2 eV EP Low E.P. 20-26 F7.2 --- gf Log gf 27-31 I5 10-4nm W_1 []? Equivalent width, 1992 Jun 17 32-36 F5.2 --- E_1 []? log epsilon, 1992 Jun 17 37-41 I5 10-4nm W_2 []? Equivalent width, 1993 Dec 6 42-46 F5.2 --- E_2 []? log epsilon, 1993 Dec 6 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Species Ion species 6-14 F9.2 0.1nm Lambda Wavelength 15-19 F5.2 eV EP Low E.P. 20-26 F7.2 --- gf Log gf 27-31 I5 10-4nm W_1 []? Equivalent width, 1994 Apr 29 32-36 F5.2 --- E_1 []? log epsilon, 1994 Apr 29 37-41 I5 10-4nm W_2 []? Equivalent width, 1995 May 15 42-46 F5.2 --- E_2 []? log epsilon, 1995 May 15 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Species Ion species 6-14 F9.2 0.1nm Lambda Wavelength 15-19 F5.2 eV EP Low E.P. 20-26 F7.2 --- gf Log gf 27-31 I5 10-4nm W_1 []? Equivalent width, 1994 Jun 24&25 32-36 F5.2 --- E_1 []? log epsilon, 1994 Jun 24&25 37 1X --- --- Blank 38 A1 --- l_W_2 [<] limiting character for W_2 39-41 I3 10-4nm W_2 []? Equivalent width, 1994 Jun 26&27 42 A1 --- l_E_2 [<] limiting character for E_2 43-46 F4.2 --- E_2 []? log epsilon, 1994 Jun 26&27 47-51 I5 10-4nm W_3 []? Equivalent width, 1996 Apr 9&10 52-56 F5.2 --- E_3 []? log epsilon, 1996 Apr 9&10 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table6.dat table7.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 A5 --- Species Ion species 6-14 F9.2 0.1nm Lambda Wavelength 15-19 F5.2 eV EP Low E.P. 20-26 F7.2 --- gf Log gf 27-31 I5 10-4nm W_1 Equivalent width 32-36 F5.2 --- E_1 log epsilon -------------------------------------------------------------------------------- ================================================================================ (End) Lee Brotzman [ADS] 26-Sep-1997