... XDINs

Table 1 is only available in electronic form at http://www.aanda.org

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... crust

The words "suspended crust'' has been used in a different context already with respect to quark stars; i.e. the electro-magnetically suspended crust at hundreds of Fermi's above the quark star surface (e.g. Alcock et al. 1986) instead of a few quark star radii as in our case.

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... decelerate

The damping term is by far the dominant term in the equations of motion of the shell due to the high conductivity of the shell, estimated by $\sigma = n_{\rm e,th}e^2\lambda/\left(m_{\rm e}c_{\rm s}\right)$. Here $n_{\rm e,th}$ is the number density of thermal electrons, $c_{\rm s}$ is the sound speed, the mean free path is given by $\lambda = 1/\left(n_{\rm e,th}\sigma_{\rm T}\right)$, and $\sigma_{\rm T}$ is the Thompson scattering cross section.

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... bursts

If $R_{\rm in} \le R_{\rm QS}$ then areas of the shell are in contact with the star. In this case, it is easy to imagine that the shell will experience a major disruption as inner sections are converted to CFL matter during contact probably destroying the entire shell; this could have applications to other explosive phenomena and is beyond the self-similar picture presented here.

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... be

Equation (31) is a direct measure of the star's radius once $T_{\rm BB}$ (or $L_{\rm X}$) and $\dot{P}$ are measured. This could become crucial for deriving the Mass-Radius relationship for these objects. The mass (more precisely M/R) could be derived from photon redshifts.

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... chunks)

In the cases where the shell moves in and out without pieces breaking off, there would be associated $\dot{P}$ variations without SGR bursts.

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... redshift

If the line is from ionized iron, the rest energy can increase up to 6.7 keV thus a redshift up to 5% is allowed, reducing the lower limit on the distance of the iron emitting gas from the star to $\sim 30$ km.

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... thickness

The heat penetration depth is given as $\Delta R = c_{\rm s} t_{\rm ff}$ where $c_{\rm s}\sim c/\sqrt{3}$ is the CFL sound speed and $t_{\rm ff}$ is the free fall timescale given by Eq. (49). We get $\Delta R \simeq 10^{4}\ {\rm cm}\ B_{15}\times (\eta_{0.1}f(\alpha)/E_{\rm b, 47})^{1/4}$.

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... radius

It was suggested that the minimum radius of RXJ1856 might exceed 14 km thus favoring stiff equations of state (Trümper 2005). We argue that the inferred radius is in fact the location of the iron shell. Indeed, the temperature of the cool component was measured to be <33 eV at the $3\sigma$level (Burwitz et al. 2003). In our model, it implies $T_{\rm sh,eff} < 33$ eV or $R_{\rm m} > (T_{\rm BB}/T_{\rm sh, eff})^{2} R_{\rm QS}\simeq (60./33.)^{2} R_{\rm QS}$. That is, $R_{\rm m} > 40$ km assuming $R_{\rm QS}\sim 10$ km.

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