The evolution of 19 stars from 0.8 to

is followed from the zero age main sequence (ZAMS) up to either the He-flash for low-mass stars (

), to the early asymptotic giant branch (E-AGB, 1.5

), or to the end of core C-burning for massive stars (M> 9

The tracks in the Hertzsprung-Russell (HR) and in the

versus

diagrams are given in Figs. 1 (click here) to 3 (click here), while the lifetimes (as defined in Paper I) in the different nuclear burning phases and the ratio

of the lifetimes in the He- and H-burning phases are summarized in Table 1 (click here).

Figure 1: Evolutionary tracks in the HR diagram for the models at Z=0.1, Y=0.48 with mass loss and moderate overshooting. For clarity, only the main sequence has been drawn for

, the full tracks of which are represented in Fig. 2 (click here). Thick parts of the tracks correspond to core H or He burning phases

Figure 2: Same as Fig. 1 (click here), but for the 20, 25 and

stars. Triangles, squares and circles locate the position of the stars on each track when they become WNL, WNE and WC, respectively. Open symbols refer to the

model star

Figure 3: Evolutionary tracks in the

diagram, where

and

are the central density and temperature, respectively, for the models at Z=0.1, Y=0.48 with mass loss and moderate overshooting. Thick parts of the tracks correspond to the main sequence (MS) and core He burning (CHeB) phases. The labels on each track indicate the stellar initial masses

Initial	H-burning	He-burning	C-burning
mass	phase ()	phase ()	phase ()
	2.31(6)	1.19(6)	6.12(4)	0.515
40	2.17(6)	0.52(6)	1.62(4)	0.240
25	2.94(6)	0.54(6)	1.35(4)	0.184
20	3.57(6)	0.64(6)	1.33(4)	0.179
15	4.84(6)	0.79(6)	1.67(4)	0.163
12	6.44(6)	1.03(6)	2.79(4)	0.160
9	1.01(7)	1.67(6)	6.18(4)	0.165
7	1.63(7)	2.82(6)		0.173
5	3.58(7)	6.75(6)		0.189
4	6.43(7)	1.20(7)		0.187
3	1.47(8)	2.84(7)		0.193
2.5	2.53(8)	4.90(7)		0.194
2	4.97(8)	9.49(7)		0.191
1.7	8.23(8)	1.24(8)		0.151
1.5	1.22(9)
1.25	2.17(9)
1	3.84(9)
0.9	5.69(9)
0.8	8.84(9)

Table 1: Core nuclear burning lifetimes at Z=0.1, Y=0.48 (in 10ⁿ yr, n being given in parenthesis)

Figure 4: Evolutionary tracks in the HR diagram for

star models at different metallicities as labeled on each track

Interesting properties of the high metallicity models emerge when compared to lower metallicity ones. A detailed analysis is presented in a separate paper (Mowlavi et al. 1997). Let us just mention here that:

- the tracks at Z=0.10 are hotter and more luminous than the ones at Z=0.04 or 0.02 presented in Papers II and III. This is illustrated in Fig. 4 (click here) for a

track;

- as a consequence of the lower initial hydrogen content and higher luminosities, both the MS and the core helium burning (CHeB) phases are much shorter than the corresponding lifetimes of the previous calculations at

(a factor 2 to 3 as compared to the Z=0.04 models);

- the maximum initial mass leading to the helium flash at the onset of CHeB is

- the

star enters the WNL phase very early during core hydrogen burning, and looses

during the MS. This rapid decrease in the total mass translates to a drop in the surface luminosity by

1.5 orders of magnitudes. The subsequent phase of rapid, as compared to mass-loss time-scale, core contraction enables the star to enter the CHeB phase without further appreciable mass loss, and the star evolves towards a WNE Wolf-Rayet star. As for stars more massive than

, the adopted mass loss prescription leads to the ejection of their entire mass during the MS. They never reach the He-burning phase, and are likely to end their life as helium white dwarfs.

Initial mass	WNL	WNE	WC
	1.392	1.216	-
40	0.169	0.041	0.440
25	0.017	0.144	0.203
20	0.015	0.134	0.135

Table 2: Times spent by the massive models with Z=0.1, Y=0.48 as WNL, WNE and WC Wolf-Rayet stars (in 10⁶ yr)

- the lower initial mass leading to WR stars is

. Both the 20 and

models reach successively the WNL, WNE and WC Wolf-Rayet stages during their CHeB phases. The

model becomes a WNL during its MS, and WNE and WC during its CHeB phase. The

model also becomes a WNL during its MS and a WNE during its CHeB phase, but does not become a WC star, at least before the end of its core C burning phase. The times spent by the models as WNL, WNE or WC Wolf-Rayet stars are summarized in Table 2 (click here).

3. Results