SBS 1150+599A: An extremely oxygen-poor planetary nebula in the Galactic halo?

Tovmassian, G. H.; Stasińska, G.; Chavushyan, V. H.; Zharikov, S. V.; Gutierrez, C.; Prada, F.
Bibliographical reference

Astronomy and Astrophysics, v.370, p.456-467 (2001)

Advertised on:
5
2001
Number of authors
6
IAC number of authors
1
Citations
21
Refereed citations
12
Description
We report results of a spectrophotometric study of SBS 1150+599A and discuss the nature of this object based upon our data. Our study shows that SBS 1150+599A is most probably a planetary nebula located in the Galactic halo and not a cataclysmic variable as originally proposed by the authors of the Second Byurakan Survey from low resolution spectroscopy. We have further elaborated on the properties of SBS 1150+599A (now becoming PN G135.9+55.9) with tools used for planetary nebula analysis. Our photoionization models show that, in order to match the observational constraints, the oxygen abundance in the nebula is probably extremely low, around 1/500 solar, which is one order of magnitude lower than the most oxygen-poor planetary nebulae known so far. This finding has strong implications on our understanding of the formation of planetary nebulae and of the evolution of the Galactic halo.