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Nächste Seite: Coordinates and finding charts Aufwärts: Elementary Statistics Vorherige Seite: Elementary Statistics

Distribution of planetary nebulae

The distribution of PNe in galactic coordinates is typical for objects of the disk population: high concentration towards the galactic centre and towards the galactic equator (Figs.1-4).

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Fig.1  The distribution of PNe in galactic coordinates.

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Fig.2  The distribution of PNe in equatorial coordinates.

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Fig.3a  Frequency of PNe in galactic longitude.


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Fig.3b  Frequency of PNe in galactic longitude in the central region.

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Fig.4  Frequency of PNe in galactic latitude.

The distribution in galactic longitudes is more or less symmetrical (Fig.3a). But the more detailed histogram shows a somewhat lower frequency of objects between l 345$ {^\circ}$ and 355$ {^\circ}$ (Fig.3b). The concentration towards the galactic equator is very high (Fig.4) and 1275 PNe (84%) are in the region b $ \pm$ 10$ {^\circ}$.

The distribution on the celestial sphere shows again the presence of the galactic centre and the galactic equator (Fig.2). The appearance of PNe outside the centre is again not wholly symmetrical, objects between AR 12h-17h seem to be underpopulated compared with the region 19h-21h, which fact might be an observational effect.


next up previous
Nächste Seite: Coordinates and finding charts Aufwärts: Elementary Statistics Vorherige Seite: Elementary Statistics
Lubos Kohoutek
2001-04-02