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HORIZONTAL BRANCH EVOLUTION

• Yong, Demarque, & Yi 2000, ApJ, 539, 928: "Mass Loss on the Horizontal Branch: an Application to NGC6791"
• Demarque, Zinn, Lee, & Yi 2000, AJ, 119, 1398: "The Metallicity Dependence of RR Lyrae Absolute Magnitudes from Synthetic Horizontal-Branch Models"
• Yi, Demarque, & Kim 1997, ApJ, 482, 677: "On the UV Bright Phase of Metal-Rich HB Stars"
• Yi, Lee, & Demarque 1993, ApJ, 411, L25: "The Effect of Livermore OPAL Opacities on the Evolutionary Masses of RR Lyrae Stars"

• Please read this first!



• HB TRACKS




Z(metallicity)	Y(MS)	Y(MS)
0.0001	0.2356
0.0004	0.2370
0.001	0.2409
0.004	0.2416
0.01	0.25	0.26
0.02	0.27	0.29
0.04	0.31	0.35
0.06	0.35	0.41
0.1	0.43	0.53




• HB TRACKS with FINE GRIDS




Z(metallicity)	Y(MS)	Y(MS)
0.0001	0.2356
0.0004	0.2370
0.001	0.2409
0.004	0.2416
0.01	0.25	0.26
0.02	0.27	0.29
0.04	0.31	0.35
0.06	0.35	0.41
0.1	0.43	0.53