For the first time , the interior and spectroscopic evolution of a massive star is analyzed from the zero-age main sequence ( ZAMS ) to the pre-supernova ( SN ) stage .
For this purpose , we combined stellar evolution models using the Geneva code and stellar atmospheric/wind models using CMFGEN .
With our approach , we were able to produce observables , such as a synthetic high-resolution spectrum and photometry , thereby aiding the comparison between evolution models and observed data .
Here we analyze the evolution of a non-rotating 60 \mathit { M } _ { \odot } star and its spectrum throughout its lifetime .
Interestingly , the star has a supergiant appearance ( luminosity class I ) even at the ZAMS .
We find the following evolutionary sequence of spectral types : O3 I ( at the ZAMS ) , O4 I ( middle of the H-core burning phase ) , B supergiant ( BSG ) , B hypergiant ( BHG ) , hot luminous blue variable ( LBV ; end of H-core burning ) , cool LBV ( H-shell burning through the beginning of the He-core burning phase ) , rapid evolution through late WN and early WN , early WC ( middle of He-core burning ) , and WO ( end of He-core burning until core collapse ) .
We find the following spectroscopic phase lifetimes : 3.22 \times 10 ^ { 6 } yr for the O-type , 0.34 \times 10 ^ { 5 } yr ( BSG ) , 0.79 \times 10 ^ { 5 } yr ( BHG ) , 2.35 \times 10 ^ { 5 } yr ( LBV ) , 1.05 \times 10 ^ { 5 } yr ( WN ) , 2.57 \times 10 ^ { 5 } yr ( WC ) , and 3.80 \times 10 ^ { 4 } yr ( WO ) .
Compared to previous studies , we find a much longer ( shorter ) duration for the early WN ( late WN ) phase , as well as a long-lived LBV phase .
We show that LBVs arise naturally in single-star evolution models at the end of the MS when the mass-loss rate increases as a consequence of crossing the bistability limit .
We discuss the evolution of the spectra , magnitudes , colors , and ionizing flux across the star ’ s lifetime , and the way they are related to the evolution of the interior .
We find that the absolute magnitude of the star typically changes by \sim 6 mag in optical filters across the evolution , with the star becoming significantly fainter in optical filters at the end of the evolution , when it becomes a WO just a few 10 ^ { 4 } years before the SN explosion .
We also discuss the origin of the different spectroscopic phases ( i.e. , O-type , LBV , WR ) and how they are related to evolutionary phases ( H-core burning , H-shell burning , He-core burning ) .