A new model of the creation of D and 3He in supernova of the first generation was considered. It is based on the idea that a supernova event leads simultaneously to acceleration of particles in the shock wave front and to their interactions with supernova atmosphere matter. The D, 3He, Li, Be, B and bypassed isotopes are created in these interactions. The cosmic abundances of the bypassed isotopes with A  or = 113 allowed to determine the integral proton flux I sub p (E sub p  25 MeV) = 5 x 10 to the 21/sq cm the spectral index - gamma = 3. The calculations of the D and 3He yields in various nuclear reactions at these irradiation conditions show that only the 4He(p,d)3He reaction leads to cosmic abundances of these isotopes on the assumption that all matter has been exposed

Kuznetsova, R. I.

Lavrukhina, A. K.

English

NASA Technical Reports Server

199 8.2-18
THE NUCLEOSYNTHESIS OF DEUTERILq_ AND _fELIUI,I-3
L avrukhina A.K., and Kuznetsova R.I.
V.I.Vernadsky Institute of Geochemistry and
Analytical Chemistry_ USSR Academy cf Scien-
ces, Noscow, USSR
We have suo_osed a new model of the cre-
_._-
ation of D and 3He in supernova of .,_e first
generation. It is based on the idea that a
supernova event leads simultaneously to acce-
leration of particles in the shock wave front
and to their interactions with supernova at-
mosphere matter. The D, 3He, Li, Be, B and by-
oassed isotopes are created in these interac-
tions. The cosmic abundances of the by-passed
isotopes .with A_ 113 allowed to determine the
integral croton flux - l o(Eo_ 25 MeV)=5xl021
cm-2, the soectral index-_ :3. The calcula-7. v . • °
tions of the D and _He y-,elds in varlous nuc-
lear reactions at these irradiation conditions
show that only the 4He(p,d)3He reaction leads
to cosmic abundances of these isotopes on the
ass_unption that all matter has been exposed.
I. Introduction
The nucleosynbhesis of D and 3He is possible: (I)
during expansion of the hot and dense Universe, (2)in
spallation reactions of interstella- _ matter with ga-
lactic cosmic rays, (3)in high-energy ion reacbioHs in
shock wave front during explosions of supermassive
'_ I Iobjects and supernovae of '_ype ., (4)during momentary
processes in active galactic nuclei, and (5)in reacti-
ons of interaction of neutrino from collapsing nucleo-
us of supernova. The theoretical models of the expan-
ding Universe explain the main observations of cosmo-
logical sitnificance: (1)the red-shifts of distant ga-
laxies, (2)the isotropic distribution of galaxies (3)
the homogeneous distribution of nearby ,,galaxies, _4)
the distribution of distant galaxies and radio sources,
(5)the microwave background, (6)the X-ray background,
and (7)the chemical and isotonic compositions of the
initial matter. The D, 3He, 4_le, and 7Li cosmological
abundances and the microwave background properties are
the most informative characteristics for investigation
of the physical conditions in the early Universe. The
observated tendency of the decreasing of the initial
component parts of Y o(4Hel_ 0.22-0.2_5, D/H<: (2 + 0.5)x
I0_, 3He/H=(1-2)x10-D_and _Li/H=Ix10-9 /I/ leads _o se-
rious difficulties of the cosmological models. Even
the standard isotropic and homogeneous models with the
zero lepton number /I_2/ _o not allow to obtain the
cosmic abundances of *He and deuterium at anyone ent-
https://ntrs.nasa.gov/search.jsp?R=19850026601 2020-03-20T16:48:12+00:00Z
2oo OC-8.2-I8
ropy value. Therefore the investlgation of a possibi
lity of the galactic nucleosynthesis of deuterium is
important for the problem of an initial nucleosynthe-
sis in the early Universe.
A few possible classes of objects may be respon-
sible for most of the galactic nucleosynthesis of deu--
teri_m. These are: (1)the explosion of supermassive
objects, (2)supernovae of Type I! (3)the active ga-
lactic nuclei and quasars, and (4_interstellar gas.Two
main processes have led to the formation of deuterium.
One of them is the spallation in supernova shocks /3,
4/. The propagation cf the supernova explosion shock
wave in the density gradient of the stellar envelope
results in a shock of increasing strength. The acce-
leration of matter by the shock wave has previously
been associated with the formation of cosmic rays. In
the peculiar very low density conditions of a presumed
red-giant envelope, a strong shock wave, _10 MeV per
nucleon in 10-5 to 10-4 stellar mass fraction, can re-
sult in the nearly complete spallation of He plus hea-
viers to free neutrons and protons. The neutron captu-
re on the protons has led to creation of deuterium.The
other group of processes includes the spallation reac-
tions with galactic cosmic rays in the interstellar
gas /5 ,6/.
We have examined a possibility of the creation of
deuterium and helium-3 in a massive supernova of the
first generation. Our model is based on the idea that
a supernova event leads simultaneously to explosive
nuclei burning, to acceleration of particles in the
front of a shock wave and their interactions with the
atoms in supernova atmosphere /7,8/.
2. Nuclear reactions of the synthesis of deuteri-
um and helium-_
W e haze examined the following nuclear reactions:
H(p;_*)D, 4He(p,d)JHe, 4He(p,2p)_H, 4.He(,o,lon)3He,
4He[p,pd)D, and 4He(p,2pn)D wi%h the threshold energi-
es of_30C, 18.32, 19.81, 20.55, 23.75, and 25.97 I_eV,
respectively. The second re<_ctlcn is the most probable.
Its function dependence of d_/ds_ from e has been only
determined at the proton energies of 31.5 NeV /10/, 55
_'[eV /11/, and 93 1_eV /12/. Using the method of graphic
interpolation on the energy regions of _ 30 _eV and
1lg
>100 _eV we have obtained the excitation function for
the He(p,d))He xeaction (see Figure, curve I). The
excitation function of the H(p,_V)D reaction has been
obtained in accordance with the experimental data /12,
13/ (see Figure, curve II).
The experimental daba for the cross sectioDs of
the break up reactions of 4He(p,2p)3H,4He(o on_)He
4ne(p,pd)D, and 4He(p,2pn)D are absent. However, it
was possible to make a comparlson of the total cross
section of the break up reactions at Ep=55 _eV with
201
0O 8.2-T8
2i_:)_ure. The excitation fun-
,,,,,,,,,...,.,, _ti_ns_ I -the 4,He(p,d)3LIe
5Q reaction from /10-12/_ II -
• the H(:_,[_)D - reaction
from /'12,13/. 1-from /10/,
2-from /11/, and 5-from
_,o /1 2/.
b'5 correspcndins value for the
I 4He(p,D)3i{e reaction /11/.
They are equal to 50-$0 mb
T- I4 and 40 mb res]?ectivel_,r.len-
_o _oo 4000 ce, the contribution from
Ep,MeV the bres_ u_ reactions do-
ubles the yields of deute-
rium and helium-3. [L_he ob-
served and calou!sted abundances of deuteriq.m and he-
!ium--3 - "'_ _" The c_/[culations .._vea J. . iven in the Table '_'_O •
been mad_ at the followin_ oarameters: (1)the cosmic
abundances of the seed nuclei /9/, (2)!_( _ 25_eV)=
=5xi021 era-,.,,(3)the spectral index of _U=z.5. i.he
cross-section of each reaction was averazed accord ins
to the energetic spectrua_ of galactic cosn_.ic rays, as
well as averaL:ed according to the isotopic elemental
compositions of the irradiated matter.
TABLE. The calculated and observed abundances
----of deuterium and he!ium-3(atoms/106atoms [_i'
i _ cm -2 N calculated N observe0Target iIsotope
4He i 3He ' 38"5xi0-27 4"2x105 3"7xi05
4He D i 38-.5x10 -27 4.2x105 5.2x105
i
H D 1.4x10 -30 2 .....___102
These data show tizat the created in i.he %He(p,D)
3He reaction _iounts of deuteri'um and helium-3 are
comparable with the cosmic abundances of these isoto-
, pes on the assumption that all matter has been exposed.
l_owever, if we ta/ce into consideration the contributi--
on of the break up reactions then the amount of irra-
diated matter will decrease up to _50 per cent.
3 .C onclus ions
The nucleosynthesis oT D and 3He in su*oernova of
the first generation l)u-bs a hard limitation in tempe-
lq
rature and c!lemic_Jl composition of t_.e envelopes where
mlit had taken place. J.ne temDera_dures of the C and 0
.envelopes are high (T:_I071[> rand -the D, 311e _ Li, .,De,.t_
isotopes, created by si_a!lation reactions with the CNO
nuclei, are destroied. Therefore, the D and 31-1e crea-
tion had taken place only in the atmosphere[_ of the
202 OG 8.2-18
first ge_:leration supernova and in interstellar _as
which have cosmological com?osition (h_dro6en and he-
lium). The nncleosynthesis of the Li, Be and B isoto-
pes had taken place in nuclear reactions during su-
pernova events of the second generation stars /14/.
These data lead to the conclusion that the matter,
thrown of the supernova of the first generation, are
not exposed to s_ intensive irradiation in interstellar
space. This puts a limitation on models of the galac-
tic structure formation and their evolution.
The D nucleosynthesis in the first generation su-
pernovae not agree with the model of the GsRaxy forma-
tion in a process of protogalaxy collapse. This model
leads to a_overproducticn of Li, Be and B. To avoid
the excess of these elements we exsmine a model of a
homogeneous matter fragmentation with the formation of
fragments of _ (I06-I0_)Me. The collapse of latter
led to formation of massive stars (M _ 100Me) of the
first generation which have simultaneously eve!red.Ho-
wever, these stars have large mass-loss rates and ex-
pose the products of nuclear burning at the surface
relatively early in their life. This material ejected
in the stellar wind can mix with a nearby interstellar
gas (and dust) prior to the supernova event. It also
leads to an overproduction of Li, Be snd B. This prob-
lem requites a detailed study.
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6. Audouze, J. et al., (1978). In: Spallation nuclear
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7. Lavrukhina, A.K. and Kuznetsova, R.I. (1979). In:
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8. Lavrukhina, A.K. and Kuznetsova, R.I. (1980), Geo-
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The nucleosynthesis of deterium and helium-3

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