The striking case of RX J1856.5-3754
Optical excess
of ~6 over the Rayleigh-Jeans tail of the X-ray best fitting bb (Walter & Lattimer, 2002)
No X-ray
pulsations: upper
limit on the pulsed fraction £1% (Burwitz et al., 2003)
previous d ~120-140 pc (Kaplan et al, 2001; Walter & Lattimer, 2002)
Þ revised d
~175 pc (Kaplan et al., 2003, Korea meeting)
Þ radiation radius of only 7-8 km!
€ Two-T model: x-ray = caps; optical = star
surface (Pons et al. 2002; Walter & Lattimer, 2002)
€
€ Is it the first quark/strange
star
discovered? (Drake et al, 2002; Xu, 2002)
€
€ Phase transition to a solid
surface (B>few x1013 G) (Turolla et al.
2003)
(Pons et al, 2002; Walter &
Lattimer, 2002 )