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J/A+A/344/943       Sh 138 BVRIJHK photometry                (Deharveng+ 1999)

Sh 138: a compact HII region excited by a very young cluster Deharveng L., Zavagno A., Nadeau D., Caplan J., Petit M. <Astron. Astrophys. 344, 943 (1999)> =1999A&A...344..943D (SIMBAD/NED BibCode)
ADC_Keywords: H II regions ; Photometry, UBVRIJKLMNH ; Clusters, open Keywords: pre-main sequence - ISM:: HII regions - ISM: individual objects: Sh 138 - Galaxy: open clusters and associations: individual: Sh 138 - infrared: stars Abstract: We present a photometric and spectroscopic study of the compact HII region Sh 138 and its associated stellar cluster. 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. 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/pc2 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). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 96 424 Coordinates and photometry of all the stars
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Running number of the star 5- 10 F6.3 arcmin Xpos tangential coordinate (1) 12- 17 F6.3 arcmin Ypos tangential coordinate (1) 19- 20 I2 h RAh [22] Right ascension (J2000.0) 22- 23 I2 min RAm Right ascension (J2000.0) 25- 29 F5.2 s RAs Right ascension (J2000.0) 31 A1 --- DE- Declination sign (J2000.0) 32- 33 I2 deg DEd Declination (J2000.0) 35- 36 I2 arcmin DEm Declination (J2000.0) 38- 41 F4.1 arcsec DEs Declination (J2000.0) 43- 47 F5.2 mag Vmag ? V magnitude 49- 53 F5.2 mag B-V ? B-V colour index 55- 59 F5.2 mag V-R ? V-R colour index 61- 65 F5.2 mag R-I ? R-I colour index 67- 71 F5.2 mag V-I ? V-I colour index 73- 77 F5.2 mag Kmag ? K magnitude 79- 83 F5.2 mag J-K ? J-K colour index 85- 89 F5.2 mag J-H ? J-H colour index 91- 95 F5.2 mag H-K ? H-K colour index
Note (1): Xpos and Ypos are with respect to RA=22h32m45.6s, Dec=58°28'16.8"
Acknowledgements: James Caplan
(End) Patricia Bauer [CDS] 01-Feb-1999
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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