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The 6.67 hour period CCO in RCW 103: a descendant of Thorne-Zytkow object?

The 6.67 hour period CCO in RCW 103: a descendant of Thorne-Zytkow object?. X. W. Liu, R. X. Xu, G. J. Qiao, J. L. Han, Z. W. Han, and X. D. Li, submitted to ApJ arXiv:1207.4687v1 [astro-ph.HE]. XiongWei Liu (Peking University) 刘雄伟 16 Aug. 2012, Urumchi. Background

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The 6.67 hour period CCO in RCW 103: a descendant of Thorne-Zytkow object?

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  1. The 6.67 hour period CCO in RCW 103: a descendant of Thorne-Zytkow object? X. W. Liu, R. X. Xu, G. J. Qiao, J. L. Han, Z. W. Han, and X. D. Li, submitted to ApJ arXiv:1207.4687v1 [astro-ph.HE] XiongWei Liu (Peking University) 刘雄伟 16 Aug. 2012, Urumchi

  2. Background The 6.67h period X-ray source in RCW 103 • From TZO to extremely long period CCO What is a TZO? How to spin down? Why looks like a CCO? • Discussion

  3. BackgroundThe 6.67h period X-ray source in RCW 103

  4. The 6.67h period X-ray source in RCW 103 1E161348-5055 (Tuohy, 1980) soft x-ray ~1033 – 1035 erg s-1, no radio or optical counterpart SNR RCW 103 ~2 kyr (Carter, 1997) ~3.3 kpc

  5. The 6.67h period X-ray source in RCW 103 6.67-hour periodicity modulation (2006, De Luca) any other periodicities with P >12 ms are excluded with high confidence

  6. The 6.67h period X-ray source in RCW 103 Long-term flux variability (2006, De Luca)

  7. The 6.67h period X-ray source in RCW 103 Period derivative(2011, Esposito)

  8. The 6.67h period X-ray source in RCW 103 Candidate 1: Orbit period of a binary? Neutron star + low mass MS star (2006, De Luca) MNS=1.4 M⊙, Porbit=6.67h black line: Mcom = 0.4 M⊙, e = 0.2; red line: Mcom = 0.2 M⊙, e = 0.5. wind velocity: 300 km s-1. Problems: How could the company star survive from the supernova explosion and escape the observations? Why didn’t find the spin period?

  9. The 6.67h period X-ray source in RCW 103 Candidate 2: Magnetar with a fallback disk? (2006, De Luca) magnetic field: 5×1015 G disc mass: 3×10-5 M⊙ birth period: 0.3 s Problems: Why doesn’t like other “magnetars”? (P: 2~12s) AXP 0142, Disk (Wang 2006) SGR 0418+5729, Disk spin-down (Alpar 2011)

  10. From TZO to extremely long period CCOWhat is a TZO?How to spin down?Why looks like a CCO? Candidate 3:

  11. What is a TZO? Thorne-Zytkow Object (TZO) (Thorne & Zytkow, 1977): A massive star with a degenerate neutron core Structure of a TZO 20-200 TZOs existing in the Galaxy (Podsiadlowski et al. 1995), But identified none.

  12. How to spin down? Philipp et al. 1995, MNRAS In the steady-burning phase Slowly spin-down In the neutrino runaway phase Spin-up to ~10ms But they ignored the interaction between envelope and magnetosphere, and did not consider the out-flow

  13. How to spin down? Qualitatively: When the envelope particals go in to the core (inflow), they are accelerated by the magnetosphere; When some of them go out (ourflow), they take away angular momentum from the core. Notes: it is radiation press dominanted it is not disk accretion there is no Alphen radius

  14. How to spin down? Quantitatively: Structure of the convection envelope Mass conservation: Boundary conditions: Hypothesis: (flow structure)

  15. How to spin down? Quantitatively: Interaction between magnetosphere and particals, rotational velocity:

  16. How to spin down? Quantitatively: Conservation of angular momentum:

  17. How to spin down? Quantitatively: Main results: • The spin evolution of the compact core in a TZ˙O with different core parameters and same model parameters

  18. How to spin down? Quantitatively: Main results: • The spin evolution of the compact core in a TZ˙O with different model parameters and same core parameters

  19. Why looks like a CCO? • Case a: About 2000 years ago, the more massive star of a binary collapsed in a supernova explosion, which produced RCW 103 and a compact star. The compact star embedded in the companion MSS and formed a TZO. The core spun-down to the co-rotational period (6.67 hr) with the envelop within 2000 years, when a burst destroyed the envelope (e.g., due to a phase transition of its crust, or other processes such as thermal nuclear explosion). As a result, the envelope mixed together with the supernova remnant RCW 103, and the core (1E1613) became a CCO. • Case b: More than 2000 years ago, a neutron star embedded in or swallowed by its companion star and formed a TZO. About 2000 years ago, a powerful burst (the whole neutron star occurred a phase transition or a quark-nova) took place , when it has spun-down to 6.67 hr and the previous supernova remnant has faded away. The burst destroyed the TZO envelope and formed an analogous supernova remnant, i.e. RCW 103. The young quark star (1E1613) became a CCO.

  20. Summary and discussion • The core of a TZO would spin down quickly to the corotate period with envelope braked by the interaction between the envelope and magnetosphere; • The core could manifest as a long period isolated compact star if a energetic burst destroy the envelope; • The CCO in RCW 103, 1E1613, might be a descendant of a disrupted TZO. • It also could be one of the possible origin of the extremely long period objects in X-ray binaries. Such as the ~2.7 hour period X-ray source in 2S 0114+65 and the ~1.5 hour period X-ray source in 4U 2206+54. Thanks!

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