J/A+A/650/A203 Effects of IMG on Galactic chemical enrichment (Goswami+, 2021)
The effects of the initial mass function on Galactic chemical enrichment.
Goswami S., Slemer A., Marigo P., Bressan A., Silva L., Spera M., Boco L.,
Grisoni V., Pantoni L., Lapi A.
<Astron. Astrophys. 650, A203 (2021)>
=2021A&A...650A.203G 2021A&A...650A.203G (SIMBAD/NED BibCode)
ADC_Keywords: Models, evolutionary ; Milky Way ; Abundances
Keywords: stars: abundances - stars: massive - Galaxy: abundances -
Galaxy: disc - Galaxy: solar neighborhood - Galaxy: evolution
Abstract:
We have been seeing mounting evidence that the stellar initial mass
function (IMF) might extend far beyond the canonical Mi∼100M☉
limit, but the impact of such a hypothesis on the chemical enrichment
of galaxies is yet to be clarified.
We aim to address this question by analysing the observed abundances
of thin- and thick-disc stars in the Milky Way with chemical evolution
models that account for the contribution of very massive stars dying
as pair instability supernovae.
We built new sets of chemical yields from massive and very massive
stars up to Mi∼350M☉ by combining the wind ejecta extracted from
our hydrostatic stellar evolution models with explosion ejecta from
the literature. Using a simple chemical evolution code, we analysed
the effects of adopting different yield tables by comparing
predictions against observations of stars in the solar vicinity.
After several tests, we set our focus on the [O/Fe] ratio that best
separates the chemical patterns of the two Milky Way components. We nd
that with a standard IMF, truncated at Mi∼100M☉, we can
reproduce various observational constraints for thin-disc stars;
however, the same IMF fails to account for the [O/Fe] ratios of
thick-disc stars. The best results are obtained by extending the IMF
up to Mi=350M☉; while including the chemical ejecta of very
massive stars in the form of winds and pair instability supernova
(PISN) explosions.
Our study indicates that PISN may have played a significant role in
shaping the chemical evolution of the thick disc of the Milky Way.
Including their chemical yields makes it easier to reproduce not only
the level of the a-enhancement, but also the observed slope of
thick-disc stars in the [O/Fe] versus [Fe/H] diagram. The bottom line
is that the contribution of very massive stars to the chemical
enrichment of galaxies is potentially quite important and should not
be neglected in models of chemical evolution.
Description:
We present the ejecta tables (set TW) for massive and very massive
stars used in this work that will be available on-line, for 4 values
of the initial metallicity (Zi=0.0001,0.001,0.006,0.02) and 30 values
of the initial mass (8≤Mi/M☉≤350). Each table corresponds to
one selected value of Zi.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
abundini.dat 491 4 Initial stellar abundance for the 4 tables
z0p0001.dat 765 27 Explosive Total (not newly formed) ejecta
for Z=0.0001
z0p001.dat 765 27 Explosive Total (not newly formed) ejecta
for Z=0.001
z0p006.dat 765 27 Explosive Total (not newly formed) ejecta
for Z=0.0006
z0p02.dat 765 27 Explosive Total (not newly formed) ejecta
for Z=0.02
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Byte-by-byte Description of file: abundini.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Table Table name
13- 23 E11.5 --- H Initial H stellar abundance
25- 35 E11.5 --- He3 Initial 3He stellar abundance
37- 47 E11.5 --- He4 Initial 4He stellar abundance
49- 59 E11.5 --- Li7 Initial 7Li stellar abundance
61- 71 E11.5 --- Be7 Initial 7Be stellar abundance
73- 83 E11.5 --- C12 Initial 12C stellar abundance
85- 95 E11.5 --- C13 Initial 13C stellar abundance
97-107 E11.5 --- N14 Initial 14N stellar abundance
109-119 E11.5 --- N15 Initial 15N stellar abundance
121-131 E11.5 --- O16 Initial 16O stellar abundance
133-143 E11.5 --- O17 Initial 17O stellar abundance
145-155 E11.5 --- O18 Initial 18O stellar abundance
157-167 E11.5 --- F19 Initial 19F stellar abundance
169-179 E11.5 --- Ne20 Initial 20Ne stellar abundance
181-191 E11.5 --- Ne21 Initial 21Ne stellar abundance
193-203 E11.5 --- Ne22 Initial 22Ne stellar abundance
205-215 E11.5 --- Na23 Initial 23Na stellar abundance
217-227 E11.5 --- Mg24 Initial 24Mg stellar abundance
229-239 E11.5 --- Mg25 Initial 25Mg stellar abundance
241-251 E11.5 --- Mg26 Initial 26Mg stellar abundance
253-263 E11.5 --- Al26 Initial 26Al stellar abundance
265-275 E11.5 --- Al27 Initial 27Al stellar abundance
277-287 E11.5 --- Si28 Initial 28Si stellar abundance
289-299 E11.5 --- Si29 Initial 20Si stellar abundance
301-311 E11.5 --- P Initial P stellar abundance
313-323 E11.5 --- S Initial S stellar abundance
325-335 E11.5 --- Cl Initial Cl stellar abundance
337-347 E11.5 --- Ar Initial Ar stellar abundance
349-359 E11.5 --- K Initial K stellar abundance
361-371 E11.5 --- Ca Initial Ca stellar abundance
373-383 E11.5 --- Sc Initial Sc stellar abundance
385-395 E11.5 --- Ti Initial Ti stellar abundance
397-407 E11.5 --- V Initial V stellar abundance
409-419 E11.5 --- Cr Initial Cr stellar abundance
421-431 E11.5 --- Mn Initial Mn stellar abundance
433-443 E11.5 --- Fe Initial Fe stellar abundance
445-455 E11.5 --- Co Initial Co stellar abundance
457-467 E11.5 --- Ni Initial Ni stellar abundance
469-479 E11.5 --- Cu Initial Cu stellar abundance
481-491 E11.5 --- Zn Initial Zn stellar abundance
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Byte-by-byte Description of file (#): z*
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Bytes Format Units Label Explanations
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9- 15 F7.5 --- Zi Initial metallicity
24- 30 F7.5 --- Yi Initial Y abundance
37- 45 F9.5 Msun Mini Mass of the star at the zero-age main sequence
(Mini2 for z0p0001.dat)
52- 60 F9.5 Msun Mfin Mass of the star at the beginning of central
carbon burning (almost equivalent to the
pre-SN mass)
67- 75 F9.5 Msun MHe Mass of the He-core at the beginning of
central carbon burning
82- 90 F9.5 Msun MCO Mass of CO-core at the beginning of central
carbon burning
97-105 F9.5 Msun Mcut Mass-cut, in a pre-supernova model, enclosing
the entire mass that will collapse and form
the compact remnant
118-122 A5 --- PreSNPhase Pre SN phase (1)
129-138 A10 --- SNType SN type (2)
142-150 F9.5 Msun Mtot Total mass
155-165 E11.6 --- Mini-Mtot Difference between the initial mass and
total mass
170-180 E11.6 --- H 1H yield (3)
185-195 E11.6 --- He3 3He yield (3)
200-210 E11.6 --- He4 4He yield (3)
215-225 E11.6 --- Li7 7Li yield (3)
230-240 E11.6 --- Be7 7Be yield (3)
245-255 E11.6 --- C12 12CO yield (3)
260-270 E11.6 --- C13 13CO yield (3)
275-285 E11.6 --- N14 14N yield (3)
290-300 E11.6 --- N15 15N yield (3)
305-315 E11.6 --- O16 16O yield (3)
320-330 E11.6 --- O17 17O yield (3)
335-345 E11.6 --- O18 18O yield (3)
350-360 E11.6 --- F19 19F yield (3)
365-375 E11.6 --- Ne20 20Ne yield (3)
380-390 E11.6 --- Ne21 21Ne yield (3)
395-405 E11.6 --- Ne22 22Ne yield (3)
410-420 E11.6 --- Na23 23Na yield (3)
425-435 E11.6 --- Mg24 24Mg yield (3)
440-450 E11.6 --- Mg25 25Mg yield (3)
455-465 E11.6 --- Mg26 26Mg yield (3)
470-480 E11.6 --- Al26 26Al yield (3)
485-495 E11.6 --- Al27 27Al yield (3)
500-510 E11.6 --- Si28 28Si yield (3)
515-525 E11.6 --- Si29 29Si yield (3)
530-540 E11.6 --- P P yield (3)
545-555 E11.6 --- S S yield (3)
560-570 E11.6 --- Cl Cl yield (3)
575-585 E11.6 --- Ar Ar yield (3)
590-600 E11.6 --- K K yield (3)
605-615 E11.6 --- Ca Ca yield (3)
620-630 E11.6 --- Sc Sc yield (3)
635-645 E11.6 --- TI Ti yield (3)
650-660 E11.6 --- V V yield (3)
665-675 E11.6 --- Cr Cr yield (3)
680-690 E11.6 --- Mn Mn yield (3)
695-705 E11.6 --- Fe Fe yield (3)
710-720 E11.6 --- Co Co yield (3)
725-735 E11.6 --- Ni Ni yield (3)
740-750 E11.6 --- Cu Cu yield (3)
755-765 E11.6 --- Zn Zn yield (3)
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Note (1): pre-SN phase as follows:
RSG = red supergiant
BSG = blue supergiant
WC = Wolf-Rayet stars enriched in carbon
WN = Wolf-Rayet stars enriched in nitrogen
WO = Wolf-Rayet stars enriched in oxygen
LBV = luminous blue variables
Note (2): SN type as follows:
fCCSN_0 = failed core collapse supernova
sCCSN_0 = successful core collapse supernova
PISN_0 = Pair instability supernova
PPISN_0 = Pulsation pair instability supernova
DBH_0 = Direct collapse to black hole
Note (3): initial stellar abundances n abundini.dat table.
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Acknowledgements:
Sabyasachi Goswami, sgoswami(at)sissa.it
(End) Patricia Vannier [CDS] 21-Jun-2021