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PHL 932: When Is a Planetary Nebula Not a Planetary Nebula?
被引:36
|作者:
Frew, David J.
[1
,2
]
Madsen, Greg J.
[3
]
O'Toole, Simon J.
[4
]
Parker, Quentin A.
[1
,4
]
机构:
[1] Macquarie Univ, Dept Phys, N Ryde, NSW 2109, Australia
[2] Perth Observ, Bickley, WA 6076, Australia
[3] Univ Sydney, Sch Phys, Sydney Inst Astron, Sydney, NSW 2006, Australia
[4] Anglo Australian Observ, Epping, NSW 1710, Australia
来源:
基金:
美国国家科学基金会;
美国国家航空航天局;
关键词:
HII regions;
ISM: clouds;
planetary nebulae: general;
stars: horizontal-branch;
stars: individual (PHL 932);
subdwarfs;
HIGH GALACTIC LATITUDES;
HOT HORIZONTAL-BRANCH;
PALOMAR-GREEN SURVEY;
SUBDWARF-B-STARS;
H-ALPHA;
SDB STARS;
INTERSTELLAR-MEDIUM;
WHITE-DWARFS;
SKY SURVEY;
STROMGREN PHOTOMETRY;
D O I:
10.1071/AS09043
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
The emission nebula around the subdwarf B (sdB) star PHL 932 is currently classified as a planetary nebula (PN) in the literature. Based on a large body of multi-wavelength data, both new and previously published, we show here that this low-excitation nebula is in fact a small Stromgren sphere (HII region) in the interstellar medium around this star. We summarise the properties of the nebula and its ionizing star, and discuss its evolutionary status. We find no compelling evidence for close binarity, arguing that PHL 932 is an ordinary sdB star. We also find that the emission nebulae around the hot DO stars PG 0108 + 101 and PG 0109 + 111 are also Stromgren spheres in the ISM, and along with PHL 932, are probably associated with the same extensive region of high-latitude molecular gas in Pisces-Pegasus.
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页码:203 / 209
页数:7
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