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Поисковые слова: arp 220
Galactic distribution and absolute magnitudes next up previous
Next: Numbers and distances Up: BASIC PROPERTIES Previous: Spectrum

Galactic distribution and absolute magnitudes

The distribution of galactic RCB stars is controversial. Several authors have argued that they belong to a thick galactic disk, and are thus old Population I stars. The evidence is their scale height in the Galaxy (400pc, [Iben & Tutukov 1985]). However, their distribution and space velocities suggest they may alternatively belong to the even older galactic bulge (Population II, [Drilling 1986]). The controversy may simply be a result of the different ways in which surveys for RCB stars and related objects have been carried out. In either case, the populations are sufficiently old that RCB stars must have relatively low masses ( $ \leq{\rm 1 M_{\odot}}$).

A growing number of RCBs has been discovered in the Large Magellanic Cloud (LMC), most recently as a result of wide field surveys ([Alcock et al. 1996]). These are the only RCB stars for which a distance is known and hence for which an absolute magnitude can be deduced. With $ M_{\rm V}\sim-4$ to -5, the LMC RCBs are 3000 - 10000 times more luminous than the Sun ([Feast 1979])



Simon Jeffery
2002-01-25