西华师范大学 China West Normal University FAST Pulsar Symposium 3 From TZO to CCO? X. W. Liu, R. X. Xu, G. J. Qiao, J. L. Han, Z. W. Han, X. D. Li, and E. P. J. van den Heuvel. arXiv1207.4687 [astro-ph.HE], submitted to ApJ 刘雄伟 Xiongwei Liu 西华师范大学 China West Normal University

Background Discussion From TZO to CCO 1. A very strange CCO 2. The TZO 1. How to brake-down quickly? 2. How to become visible? 3. Theory VS Observation Discussion

Background

1. A very strange CCO The extremely long period CCO: 1E1613 Central Compact Object in supernova remnant (CCO) 6.67 hour period. Periodicities with P > 12 ms are excluded at the 99% confidence level (De Luca et al. 2006, Nature) SNR RCW 103 Age: 2000 yr (Carter 1997) 1E1613 (Tuohy 1980) No IR or optic counterpart Origin still unknown!

1. A very strange CCO Origin from a TZO? What is the origin？ Orbital period? Spin period? Magnetar + disk B: 5×1015 G, Porigin: 0.3 s, Disk mass: 3×10-5 M⊙ (De Luca et al. 2006) Not agree with the magnetar theory and observation Other possibility： Origin from a TZO?

2. The TZO Thorne-Zytkow Object (TZO) (Thorne & Zytkow, 1977): ——A Red Giant with a NS core Common envelope Huge, Slowly spin, Convective, NS core Origin from the merger of a NS with its companion Appearance: Giant : < 9 solar mass Supergiant: > 11 solar mass

2. The TZO Thorne-Zytkow Object (TZO) (Thorne & Zytkow, 1977): Prediction: about 20-200 TZOs in the Milky Way Observation: Found nothing in the Galaxy A candidate in the Small Magellanic Cloud (Podsiadlowski et al. 1995) (Levesque et al. 2014)

From TZO to CCO

Core of a TZO: Original spins fast Invisible CCO (1E1613): Spins very slowly visible 1. How to quickly brake-down to very slowly? 2. How to become visible?

1. How to quickly brake-down to very slowly? Coupling between the magnetic field of the NS core and the ionized envelope. Brake-down timescale: T < 2000 yr with normal parameters. Very quickly. Convection of the envelope takes away the angular momentum from inner region to outer region. The NS core can be braked-down to very slowly.

2. How to become visible? The core could be visible only if the envelope was destroyed. (The envelope has a small gravitational binding energy, -1047-48ergs, which is easy to be destroyed) Both the stellar wind and the instable nuclear burning can destroy the envelope within 2000 years; (Ouyed 2002) (Cheng et al. 1998) Quark nova or the phase thansition of a baryon crust can destroy the envelope immediately.

3. Theory VS Observations The destroyed envelope could become a SNR like shell, or mix with the previous SNR. (RCW 103?) Naturally form the other observational features (the remnant, age, proper motion, X-ray radiation) Self-consistent!

Discussion

Discussion One test: The abundances of the characteristic elements created in TZO phase are different from that in normal SNRs Two advantages: strong torque, brake-down very quickly envelope spins very slowly, brake-down to very slowly Three significances: Can solve the riddle of origin of the long period CCO Verify the existence of TZOs (also the non-detection of CCO in the galaxy) Provide limitation to the theory of the evolution of common envelope

西华师范大学 西华师范大学天文台（青海德令哈） Thanks!