IC 1454 is one of the most northerner PN in the sky and is located in north sector of Cefeus constellation. Its superficial magnitude is very low, so observation is a bit difficult. Besides, it's close to 7th magnitude star BD+79750 and this could give even more problems. With filter's help, indispensable in this case, the observer can see an slightly elliptical anular structure, confirmed in photography.
There are not so many studies actually on this subject, in exception to some statistical studies on nebular expansion speed.
High resolution images reveal a double shell structure, very similar to other young PNs; the main ring (visible in telescopes) is the inner shell, probably the hot-bubble, surrounded by another ring, dimmer and more homogeneous. Professional images reveal the presence of another little halo, very faint and circular, emitted during AGB phase of the progenitor star.
This nebula shows only a little stratification of ionization. If we add this to the low brightness of the central star, we can deduce the present phase of IC 1454: the core overpassed its in-shell-hydrogen combustion-phase, and this PN has now entered in its last evolutive phase. Deeper observation of its spectre could give more certainties on its evolution.
Interesting level: **** |
