Issue |
A&A
Volume 399, Number 2, February IV 2003
|
|
---|---|---|
Page(s) | 617 - 630 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20021756 | |
Published online | 07 February 2003 |
Zero-metallicity stars
II. Evolution of very massive objects with mass loss
1
Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 2, 35122 Padova, Italy
2
Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, HI 96822, Honolulu, USA
Corresponding author: P. Marigo, marigo@pd.astro.it
Received:
19
September
2002
Accepted:
26
November
2002
We present evolutionary models of zero-metallicity very massive
objects, with initial masses in the range 120 –1000
,
covering their quiescent evolution up to central carbon ignition.
In the attempt of exploring the possible occurrence of
mass loss by stellar winds, calculations are carried out with
recently-developed formalisms for the mass-loss rates driven
by radiation pressure (Kudritzki 2002) and stellar rotation
(Maeder & Meynet 2000).
The study completes the previous analysis
by Marigo et al. (2001) on the constant-mass evolution of primordial stars.
Our results indicate that
radiation pressure
(assuming a minimum metallicity
)
is not an efficient driving force of mass loss,
except for very massive stars with
.
On the other hand, stellar
rotation might play a crucial role in triggering powerful stellar winds,
once the
-limit is approached.
However, this critical condition of intense mass loss can be
maintained just for short, as the loss of angular momentum
due to mass ejection quickly leads to the spinning down of the star.
As by-product to the present work, the wind chemical yields from
massive zero-metallicity stars are presented. The
helium and metal enrichments, and the resulting
ratio
are briefly discussed.
Key words: stars: evolution / stars: interiors / stars: Hertz sprung–Russell (HR) diagram / stars: mass loss / cosmology: early Universe
© ESO, 2003
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