Superdense stars containing strange quark matterYu.L.Vartanyan, A. R. Harutyunyan
Yerevan State University
Strange quark matterIn pioneer work of V.A.Ambartsumian and G.S. Sahakian [1] it has been
shown that degenerated nuclear plasma may contain, besides neutrons, protons and electrons, also strange baryons – hyperons. In [2] G.S. Sahakian and Yu.L.Vartanian for the first time have shown that taking into account the interaction between baryons makes possible the existence of hyperons in the central regions of stable neutron stars.
A new interest towards strange nuclear plasma has arisen when Witten [3] supposed, that quark-electron plasma with a strangeness -1 per baryon may be absolutely stable state of cold superdense matter.
V.A.Ambartsumian, G.S. Sahakian, Sov.Astron.Zh., 37, 193,1960.G.S.Sahakian, Yu.L.Vartanian, Nuovo Cimento, 30, 82, 1963; Sov.Astron.Zh., 41, 193, 1964.E.Witten, Phys.Rev. D30, 272, 1984.
Strange Stars
Yu.L.Vartanyan, A.R.Arutyunyan, A.K.Grigoryan, Astrofizika, 37, 499,1994
(Astrophysics, 37, 271, 1994);
Yu.L.Vartanyan, A.R.Arutyunyan, A.K.Grigoryan,
Astronomy Letters, 21, 122, 1995.
EoS for Strange Stars
n (fm-3)
E (MeV)
-50
-30
-10
10
30
50
70
90
0 0.2 0.4 0.6 0.8
1.4
1.1
Radius-central density (SS)
0
5
10
15
0 2 4 6 8 10
1.1
7
R (km)
0/c
Mass-radius relationship (SS)
0
0.5
1
1.5
2
2.5
0 5 10 15
R (km)
M / MŸ
1.1
7
Total energy density-distance from star center: 1. M=0.5Msun, 2. M=1.44Msun, 3. M=1.86Msun
MM 5.0
0
2
4
6
8
10
0 3 6 9 12
r (km)
0/
EoS for Neutron Stars with a Strange Quark Core
2 4 6 8 10 12 14
950
975
1000
QM
NM
1/nQ 1/nN
E, Ì
ýÂ
1 / n , Ôì 3
Neutron Stars with a Strange Quark Core
Yu.L.Vartanian, A.R.Harutyunian, G.B.Alaverdyan, in the Plenary Lectures and Contributed Papers, GR 15, Pune, India, December 16-21, 1997, p.159; G.B.Alaverdyan, A.R.Harutyunyan, Yu.L.Vartanyan, Spacetime and Substance, 2, 3(8), 129, 2000; G.B.Alaverdyan, A.R.Harutyunyan, Yu.L.Vartanyan, Astrophysics, 44, 265, 2001;G.B.Alaverdyan, A.R.Arutyunyan, Yu.L.Vartanyan, Astronomy Letters, 28,24, 2002; A.R.Harutyunyan, Astrophysics, 45, 248, 2002; G.B.Alaverdyan, A.R.Harutyunyan, Yu.L.Vartanyan, Astrofizika, 46, 445, 2003.
First-order phase transition
0 2 4 6 8 10
940
960
980
1000
1020
1040
3
2
1
h
gf e
d cb
a
,
МэВ
1/n, Фм3
EoS for NS with a quark core
1014 10150.1
1
10
100
P
, М
эВ/Ф
м3
, г/см3
3a 3b 3c 3d
1 10 1000.0
0.5
1.0
1.5
2.0
2.5
f
Mp
M0
M
M /
M o
Pc , МэВ / Фм3
0.5 1.0 1.5 2.0 2.50.070
0.075
0.080
e
d
c
ba
0.7 0.8 0.9 1.0 1.1 1.2
0.0795
0.080
c
b
a
100
101
102
103
104
106
108
1010
1012
1014
Aen Ae
Конфигурация d
Rnd
=13.24 км
nd=4.3 1011
г / см3
Q
Rcore=1.73 км
,
г
/ см3
r , км
10 100 1000
0.1
1
a
f
e dc
b
M /
M
R , км
0 200 400 600 800 1000 1200 14000.06
0.07
0.08
0.09
0.10
a
e
d
c
b
M /
M
R , êì
1 10 100
10-2
10-1
100
101
102
103
104
Rnd
RNS
Rcore
R, R
nd,
R
core , km
Pc , MeV/fm3
1 10 10010-2
10-1
100
101
102
103
104
105
êì2
I , M
Pc , Ì ýÂ/Ôì
3
1,44
G
F
E
D
C
B
A
M/M
Pc