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Table · dataset · 1999

Sh 138 BVRIJHK photometry

Listed in IVOA Registry (Virtual Observatory)

We present a photometric and spectroscopic study of the compact HII region Sh 138 and its associated stellar cluster.

Description

The positions and BVRIJHK magnitudes are obtained for more than 400 stars over a field of about 4' square centred on the HII region. Sh 138 is excited by a cluster of young massive stars.

At the cluster's very centre are at least four O-B2 stars separated by less than 4". The brightest of these, both in the visible and the near infrared, exhibits a spectrum similar to those of the more massive Herbig Ae/Be stars. This star, our No. 183, is overluminous by a factor of 2.5 in the visible and four in the near IR with respect to the O9.5V star required to account for the ionization level of the HII region.

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However star 183's position in the J-H versus H-K diagram does not indicate a near-IR excess. We suggest that this star is a young massive object belonging to a binary or multiple system. The stellar cluster associated with Sh 138 is very reminiscent of the Orion Trapezium cluster: it is centrally peaked around several massive stars, and is dense - more than 550stars/pc^2^ at its centre.

The visual extinction in the cluster varies between 5mag and more than 35mag; large variations are observed over very small scales (for example, more than 20mag over less than 4" among the central massive stars).

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Catalogue records · 2

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Stated by source
Infrared · Optical
Inferred from text
Astronomical sciences 72%
Provenance · 1 source records, 10 field assertions
SourceKeyLast seenRaw
IVOA Registry (Virtual Observatory)ivo://cds.vizier/j/a+a/344/94315 d agoJSON v1
FieldAssertionExtractorEvidence
access_levelsource · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[field].anzsrc:group:5101enrichment · IVOA Registrytaxonomy-embedding@1.1.0title+keywords+description (72%)
concepts[field].local:field:astronomymapping · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[modality].ivoa_waveband:infraredsource · IVOA Registryconnector:ivoa_registry@1.0.0
concepts[modality].ivoa_waveband:opticalsource · IVOA Registryconnector:ivoa_registry@1.0.0
descriptionsource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_description
license_textsource · IVOA Registryconnector:ivoa_registry@1.0.0
publication_datesource · IVOA Registryconnector:ivoa_registry@1.0.0
titlesource · IVOA Registryconnector:ivoa_registry@1.0.0rr.resource.res_title
updated_datesource · IVOA Registryconnector:ivoa_registry@1.0.0