Fridolin Weber San Diego State University San Diego, California USA

Transcription

1 Fridolin Weber San Diego State University San Diego, California USA IAU Symposium 291 Neutron Stars and Pulsars: Challenges and OpportuniEes afer 80 years IAU General Assembly XXVIII August 2012, Beijing, China

2 Ø Strange Quark Stars versus Neutron Stars Ø Explore Testable Predic<ons q Rapid rotaeon q Ultra- high electric fields q OscillaEons of electron sea q Meissner effect (vortex expulsion) q Pycnonuclear reaceons Ø Summary

3 Strange Quark Star Neutron Star Surface Hydrogen/Helium plasma Iron nuclei Surface Outer Crust Ions Electron gas Outer Crust Inner Crust Heavy ions Relativistic electron gas Superfluid neutrons Outer Core Neutrons, protons Electrons, muons Core Electrons u,d,s quarks (color-superconducting) F. Weber (SDSU, 2012) I Radii < 10 km Masses ~1 to 2 M sun Radii > 10 km Inner Core Neutrons Superconducting protons Electrons, muons Hyperons (Σ, Λ, Ξ) Deltas (Δ) Boson (π, K) condensates Deconfined (u,d,s) quarks / colorsuperconducting quark matter

4 Quark Stars* vs Neutron Stars Ø Made enerely of deconfined quarks and leptons Ø Self- bound (M ~ R 3 ) Ø Baryon number O(1) < B < Ø Electron sea at surface (super- high electric fields) Ø May posses outer crusts Ø No inner crusts Ø Two- parameter stellar sequences Ø May contain deconfined quark maaer only in stellar core Ø Bound by gravity Ø to Ø Absent Ø Outer crusts Ø Inner crusts Ø One- parameter stellar sequence *E. Wiaen, Phys. Rev. D 30 (1984) 272; Alcock, Farhi, Olinto, ApJ 310 (1986) 261; Alcock & Olinto, Ann. Rev. Nucl. Part. Sci. 38 (1988) 161; Madsen, Lecture Notes Phys. 516 (1999) 162.

5 M/M sun Mass- radius relaeonship of neutron stars Black holes 1 Neutron stars void of compact stars 2 unstable equilibrium 3 configurations White dwarfs Planets R (km)

6 Mass- radius relaeonship of neutron stars and strange quark stars d bc b a d b a b a

7 RotaEon at Sub- Millisecond Periods Kepler Period (msec) Observed masses and rotaeonal periods Neutron stars Strange quark stars

8 Electrically Charged Quark Stars Energy density of electric field is of same order as energy density of quark maaer! µ F kl F kl T µ =(P + )u u µ + P µ ideal fluid F µl F l GravitaEonal mass Increases by up to 15%. Radius increases by up to 5%. R. Negreiros, FW, M. Malheiro, V. Usov, PRD 80 (2009)

9 Electrically Charged Quark Stars (cont.) Electron sphere may be differeneally rotaeng! I = ( + ) B = const E ( + )R Could explain observed magneec fields of CCOs R. Negreiros, I. Mishustin, S. Schramm, FW, PRD 82 (2010)

10 Electron sea may perform global (hydrodynamical cyclotron) oscillaeons Frequency spectrum calculated by R. X. Xu et al.* *R. X. Xu, Bastrukov, FW, Yu, Molodtsova, PRD 85 (2012)

11 AbsorpEon features in spectrum of 1E at 0.7, 1.4 and 2.1 kev* 0.7 kev 1.4 kev 2.1 kev *G. F. Bignami, P. A. Caraveo, A. De Luca, & S. Mereghen, Nature 423 (2003) 725

12 Meissner Effect in Quark Stars made of CFL Quark Maaer Vortex expulsion reheats the quark star

13 Cooling of CFL Quark Stars via Vortex Expulsion SGRs/AXPs Negreiros, Niebergal, Ouyed, FW, PRD 81 (2010)

14 SGRs/AXPs Neutron stars Negreiros, Niebergal, Ouyed, FW, PRD 81 (2010)

15 Pycnonuclear Reactions in the Crusts of Neutron Stars White dwarf Neutron star Neutron star crust Pycnonuclear reactions

16 Pycnonuclear Reactions in the Crusts of Neutron Stars White dwarf Neutron star Strange quark matter nuggets embedded in the nuclear crust

17 Strange Quark Matter Nuggets l N u ~ N d ~ N s l A > A min (~10 to 100) l Charge-to-baryon number ratio depends on whether SQM is made of Ø ordinary quark matter, Z 0.1 (m 150 ) 2 A, or Ø color superconducting quark matter, Z 0.3 m 150 A 2/3 Farhi & Jaffe, PRD 30 (1984) 2379; Berger & Jaffe, PRC 35 (1987) 213; Alcock, Farhi, Olinto, ApJ 310 (1986) 261; Madsen, PRL 87 (2001) Madsen, PRL 87 (2001) ; Rajagopal & Wilczek, PRL 86 (2001) 3492; Oertel & Urban PRD 77 (2008)

18 R = (lattice pairs) x T Coulomb barrier x S x E -1 ) " #!! "#$% " &% '( & # * $ * * & $ * % $ &% & +'' ' (*#("(')& ( (& # & # # *!"#!$%&'()* +"#,-,'(*.'#'/&*0, 1"#2&33#4526,* 7"#2&33#8,43.(9 :"#.4;,*3,#-,40(/#<&*&2,(,* Gasques et al. PRC 72 (2005) ! Yakovlev et al. PRC 74 (2006) ! 6)89#',4(,*,8#'56.'#=6''>#-&((.',

19 Impact of quark maaer nuggets on pycnonuclear reaceon rates B. Golf, J. Hellmers, F. Weber, PRC 80 (2009)

20 q True ground state of the strong interaceon is not known q Key differences between neutron stars and quark stars emerge from the fact that quark stars are self- bound and possess electron seas at their surfaces. q Peculiar stellar properees/phenomena to watch out for: superfast rotaeon, unusually small objects (CCOs), unusually hot objects (SGRs, AGRs), absorpeon features (XDIN, CCOs), superbursts, drifing sub- pulses (R. X. Xu), quark novae (R. Ouyed),...? q Need more observed data (e.g. SkA, FAST)