8 NGC1360

  NGC1360 is an elliptical PN (Fig.8) which was discovered by Minkowski (1946). It has an asymmetrical intensity distribution in the inner part with a maximum at the North (Fig.8).

  

Figure 8: NGC1360. The PN appears larger in [O III] $\lambda$ 5007Å (right). Note that probably so-called "FLIERs'' are found in the NE and the SW

NGC1360 has an apparent angular size of about $450\hbox{$^{\prime\prime}$}\times 360\hbox{$^{\prime\prime}$}$in H$\alpha$ and about $540\hbox{$^{\prime\prime}$}\times 430\hbox{$^{\prime\prime}$}$ in [O III] $\lambda$ 5007Å. At a HIPPARCOS distance of 350pc (Acker et al. 1998) its linear size is about $0.46\times 0.36$pc. Given an [O III] expansion velocity of $v_{\rm exp} = 28\,{\rm km~s^{-1}}$ (Sabbadin 1984), the expansion time of the PN can be estimated from its largest extension to be about 16000 years.

A close look onto the PN images shows some features which look like turbulences towards the SE. Moreover, FLIERs (cf. Dwarkadas & Balick 1998) are visible outside the main nebula along its axis (Fig.8).

As interesting as PN NGC1360 is its exciting star: It is one out of four extremely hot "H-normal'' CSPN (the others are the CSPNe NGC6853, NGC4361, and NGC3587). All have been detected by EUVE, the CSPNe NGC1360 and NGC6853, were detected by ROSAT, too. Since the CSPN NGC1360 is the brightest of this group, it is of considerable interest for testing NLTE models. NLTE model atmosphere analyses (Hoare et al. 1996) revealed $\mbox{$T_\mathrm{eff}$}\hspace{-0.5mm} =\hspace{-0.5mm} 110~\mathrm{kK}$ and $\log g\hspace{-0.5mm} =\hspace{-0.5mm} 6$.