X-Nico

2 unusual facts about Planetary nebula


Planetary nebula

He later found that many nebulous objects such as the Andromeda Nebula (as it was then known) had spectra that were quite similar.

Physicists showed in the 1920s that in gas at extremely low densities, electrons can populate excited metastable energy levels in atoms and ions which at higher densities are rapidly de-excited by collisions.


Collisional excitation

In astronomy, collisional excitation gives rise to spectral lines in the spectra of astronomical objects such as planetary nebulae and H II regions.

Soyuz 13

The first satellite UV spectrogram of a planetary nebula (IC 2149 in Auriga) was obtained, revealing lines of aluminium and titanium - elements not previously observed in objects of that type.


see also

C59

Caldwell 59 (NGC 3242, the Ghost of Jupiter), a planetary nebula in the constellation Hydra