1. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 1 NUCLEAR MATTER EQUATIONS OF STATE AND THE NEUTRON STARS M. Urbanec 1, E. Běták 1,2, Z. Stuchlík 1 1 Fac. of Philos. & Sci., Silesian Univ., Opava, Czech Rep. 2 Inst. of Physics, Slovak Acad. Sci., Bratislava, Slovakia (betak@savba.sk http://www.fu.sav.sk/~betak) betak@savba.sk

2. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 2 Parametrized description of asymmetric nuclear matter corresponding to the relativistic mean field theory – fitting of results of Dirac-Brueckner-Hartree-Fok. nucleons (n, p), iso-scalar mesons (σ, ω), iso-vector mesons (ρ, δ) vector cross-interactions included Lagrangian

3. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 3 Parameters (fitted by Gmuca & Bunta to DBHF calculations of Huber et al.) withwithoutvector cross interaction g σ 2 90.532 86.432 g ω 2 108.95106.89 g ρ 2 36.681 28.795 g δ 2 28.739 25.170 b σ 0.0043852 0.0033779 c σ -0.0052045-0.0037762 c ω -0.0001421-0.001050 Λ V 0.10647-

4. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 4 Contruction of static configuration Space-time interval given by Schwarzschild metric (c=G=1) where Hydrostatic equilibrium is given by Tolman-Oppenheimer-Volkov eq. and is the mass inside the sphere of radius r

5. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 5 Neutron star radii: Our calculations: 11.5 to 13 km Neutron star masses: Compilation of experimental data (Lattimer & Prakash 2007): Typically very close to 1.4 M Sun, but two most massive objects reported with (2.44±0.27) M Sun and (2.1±0.2) M Sun. Our calculations: not more than 2.46 M Sun fo pure neutron matter (or 2.41 M Sun for proton fraction 0.1) Causality limit Not reached with inclusion of the vector cross interaction and not narrowing permissible ranges of masses.

6. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 6

7. 7

8. 8

9. 9

10. 10

11. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 11

12. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 12

13. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 13CONCLUSIONS INPUTS: INPUTS: - Relativistic man-field Brueckner-Hartree-Fock in parametrized form with vector cross interaction for set of proton fractions from 0 (pure neutron matter) up to 0.18 - σ, ω, ρ and δ mesons - Tolman-Oppenheimer-Volkov eq. OUTPUT: OUTPUT: radius and mass of the neutron star CHECK for possible causality violation CHECK for possible causality violation RESULTS: RESULTS: possible masses and radii of neutron stars - upper mass limit: 2.46 M Sun - radii: 11.5 to 13 km (in good agreement with both other calculations and masses obtained from observed data) Masses and radii somewhat smaller with than without vector cross interaction; more sensitivity to the proton fraction.

14. FINUSTAR-II - Aghios Nikolaos, Sept. 2007 14 Thank you for your attention