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Titolo:
Visual binaries among high-mass stars - An adaptive optics survey of OB stars in the NGC6611 cluster
Autore:
Duchene, G; Simon, T; Eisloffel, J; Bouvier, J;
Indirizzi:
Observ Grenoble, Astrophys Lab, F-38041 Grenoble 9, France Observ Grenoble Grenoble France 9 rophys Lab, F-38041 Grenoble 9, France Univ Calif Los Angeles, Div Astron & Astrophys, Los Angeles, CA 90095 USA Univ Calif Los Angeles Los Angeles CA USA 90095 Los Angeles, CA 90095 USA Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA Univ Hawaii Honolulu HI USA 96822 ii, Inst Astron, Honolulu, HI 96822 USA Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany Thuringer Landessternwarte Tautenburg Tautenburg Germany D-07778 Germany
Titolo Testata:
ASTRONOMY & ASTROPHYSICS
fascicolo: 1, volume: 379, anno: 2001,
pagine: 147 - 161
SICI:
1432-0746(200111)379:1<147:VBAHS->2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
ORION NEBULA CLUSTER; ICCD SPECKLE OBSERVATIONS; FRANCE-HAWAII TELESCOPE; TRAPEZIUM CLUSTER; FORMING REGIONS; EXTINCTION LAW; IMAGING SURVEY; HR DIAGRAM; EVOLUTION; NGC-6611;
Keywords:
stars : binaries : visual; stars : formation; stars : early-type; Galaxy : open clusters and associations : individual : NGC 6611;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
55
Recensione:
Indirizzi per estratti:
Indirizzo: Duchene, G Observ Grenoble, Astrophys Lab, BP 53, F-38041 Grenoble 9, France Observ Grenoble BP 53 Grenoble France 9 041 Grenoble 9, France
Citazione:
G. Duchene et al., "Visual binaries among high-mass stars - An adaptive optics survey of OB stars in the NGC6611 cluster", ASTRON ASTR, 379(1), 2001, pp. 147-161

Abstract

We have searched for visual binaries with projected separations in the range 200-3000 AU (0."1-1."5) among a sample of 96 stars in the massive young NGC6611 cluster, 60 of them being subsequently identified as high probability cluster members of mainly OB spectral type. This is the first visual binary survey among such a large and homogeneous sample of high-mass stars. Wefind an uncorrected binary frequency of 18 +/- 6% over the surveyed separation range. Considering only binaries with mass ratios q greater than or equal to 0.1, we find that OB stars in NGC6611 host more companions than solar-type field stars. We derive mass ratios for the detected binaries from their near-infrared flux ratios and conclude that about half of the detected binaries have q less than or similar to 0.2, which does not contradict the assumption that companion masses are randomly drawn from the initial mass function. There is no evidence in our sample that wide-binary properties depend upon the mass of the primary star. The high frequency of massive binaries in a cluster as rich as NGC6611 and the lack of a strong mass dependenceof their properties are difficult to reconcile with the scenario whereby massive stars form as the result of mergers of smaller stars. The canonical protostellar accretion scenario together with cloud fragmentation, on the other hand, can naturally explain most of the observed binary properties, although the very high stellar density in the protocluster is likely to require significant modification to that picture as well.

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Documento generato il 23/09/20 alle ore 00:10:27