CDROM/APJS/V92/P125
Post-AGB Evolution (Vassiliadis & Wood 1994)
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Post-Asymptotic Giant Branch Evolution of Low- to Intermediate-Mass Stars
E. Vassiliadis & P.R. Wood
<1994, ApJS, 92, 125>
=1994ApJS...92..125V
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Abstract:
In this paper, we present the results for the post-AGB phases of
stellar evolutionary sequences, complete from the main-sequence phase,
through the AGB phase, and on into the planetary nebula and white
dwarf regimes. Mass loss has been included using an empirical
formalism derived from observed mass-loss rates of planetary nebula
nuclei available in the literature and from radiation-pressure-driven
stellar wind theory. Models are calculated for initial masses 0.89,
0.95, 1.0, 1.5, 2.0, 2.5, 3.5, and 5.0 Msun, and metallicities 0.016,
0.008, 0.004, and 0.001. These abundance and mass values were chosen
to allow comparison with Galactic, and Magellanic Cloud planetary
nebulae and their nuclei. The post-AGB evolutionary sequences fall
into two distinct groups depending on when the planetary nebula nuclei
leave the AGB: one group where helium-shell burning is dominant, and
the other group where hydrogen-shell burning is dominant. Of the 27
computed sequences: 17 are hydrogen-burners, and 10 are heliumburners. In only five cases was any effort made to control the phase
of departure from the AGB. Lower mass models are more likely to leave
the AGB burning helium, as the preceding AGB evolution has a mass-loss
rate which is greatest immediately prior to a helium-shell flash. The
calculations are compared with the large observational database that
has developed over recent years for the Large Magellanic Cloud. These
calculations will be useful for determining the planetary nebula
luminosity function, and for the study of the ultraviolet excess
observed in elliptical galaxies.
Keywords:
Magellanic Clouds -- planetary nebulae: general -stars: evolution -- stars: interiors
Description:
The evolutionary tracks in Tables 3, 4, and 5 all follow the same basic
format. Each track is preceded by an indication of its initial,
main-sequence mass, M, and its metallicity, Z, for example:
(M,Y,Z)=(1.0,0.25,0.016)
(The index Y is 0.25 for every track.) The time, log Teff, and log
L/Lsun
then follows in a series of records. The end of the track is indicated
by a
blank line, and then the next track begins.
Note that this format is incompatible with the Flexible Image Transport
System ASCII table standard, and as such, these data can not be used
to generate valid FITS tables.
File Summary:
------------------------------------------------------------------------------File Name
Lrecl
Records
Explanations
------------------------------------------------------------------------------table3.dat
25
754
H-Burning PNN Evolutionary Models
table4.dat
25
419
He-Burning PNN Evolutionary Models
table5.dat
25
46
H-Like He-Burning PNN Evolutionary Model
table.tex
87
1014
LaTeX version of tables 3, 4, and 5
------------------------------------------------------------------------------Byte-by-byte Description of file: table3.dat, table4.dat, and table5.dat
Header record for each track
------------------------------------------------------------------------------Bytes Format Units
Label
Explanations
------------------------------------------------------------------------------1- 9
9X
----'(M,Y,Z)=('
10-13
F4.2
Msun
M
Initial, main-sequence mass
14-19
6X
----',0.25,' Y index is always 0.25
20-24
F5.3
--Z
Metallicity
25
1X
----')'
------------------------------------------------------------------------------Byte-by-byte Description of file: table3.dat, table4.dat, and table5.dat
Data records for each track (a blank line indicates the end of the
track)
------------------------------------------------------------------------------Bytes Format Units
Label
Explanations
------------------------------------------------------------------------------1-10
F10.1 yr
Time
Time. Taken to be zero at log Teff = 4.
11-17
F7.3
--Teff
log Teff
18-25
F8.3
--L
log L/Lsun
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(End)
Lee Brotzman [ADS] 12May-94