Table 2
Percentage of stars with initial helium mass fractions higher than 0.3, 0.35, and 0.4 that are present in the cluster at different evolution phases at 3 ages (0, i.e., initial values, 9, and 13 Gyr).
| Gyr | Phase | Yini | Yini | Yini | Yini,max |
| ≥ 0.3 | ≥ 0.35 | ≥ 0.4 | |||
|
|
|||||
| 0 | − | 49 | 33 | 21 | 0.800 |
|
|
|||||
| All | 41 | 24 | 12 | 0.763 | |
| MS | 42 | 25 | 12 | 0.752 | |
| 9 | Lower RGB | 43 | 25 | 12 | 0.763 |
| Upper RGB | 42 | 26 | 12 | 0.763 | |
| HB | 45 | 27 | 12 | 0.512 | |
| AGB | 33 | 13 | 0 | 0.382 | |
|
|
|||||
| All | 39 | 22 | 10 | 0.729 | |
| MS | 39 | 22 | 11 | 0.724 | |
| 13 | Lower RGB | 46 | 25 | 13 | 0.729 |
| Upper RGB | 38 | 22 | 10 | 0.729 | |
| HB | 37 | 12 | 0.4 | 0.407 | |
| AGB | 10 | 0 | 0 | 0.305 | |
Notes. “All” corresponds to all the cluster stars with log
above −0.5 (71 187 and 53 194 stars at 9 and 13 Gyr, respectively). “MS” corresponds to main sequence stars with log between −0.5 and 0.3. “Lower and upper RGB” corresponds to red giant branch stars with luminosities between 0.8 and 1.2 on one hand and to brighter stars up to the RGB tip on the other hand. “HB” includes all the central He-burning stars and “AGB” all the stars that are climbing the asymptotic giant branch. In the last column we give the highest value for the initial helium abundance of the stars in the different evolution phases.
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