J/PASP/98/1133      The open cluster NGC 346                    (Niemela+, 1986)

The young open cluster NGC 346 in the Small Magellanic Cloud NIEMELA V.S., MARRACO H.G, CABANNE M.L. <Publ. Astron. Soc. Pac. 98, 1133 (1986)> =1986PASP...98.1133N 1986PASP...98.1133N (SIMBAD/NED Reference)
ADC_Keywords: Magellanic Clouds; Clusters, open; Photometry, CCD Keywords: open cluster - CCD photometry - radial velocities - O-type stars Abstract: We present CCD photometry and spectrographic observations for stars in the open cluster NGC 346, which excites the largest H II region in the Small Magellanic Cloud. These observations show that NGC 346 is an extremely young cluster, containing more than 20 hot O-type stars. A radial-velocity study of the brightest stars, and also of the nearby supergiant Of star Sk 80, discloses atmospheric expansion due to strong stellar winds, but no large-amplitude radial-velocity variations due to short-period binary motion. However, two stars are probably longer period binaries. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1 31 58 NGC 346 VRI (Kron-Cousins) CCD photometry -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1 -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- Id Star number 9- 13 F5.2 mag Vmag V magnitude 16- 20 F5.2 mag V-R V-R colour index 23- 27 F5.2 mag V-I V-I colour index 31 I1 --- Rem [1-6]? Remarks (1) -------------------------------------------------------------------------------- Note (1): 1: integrated magnitude of a double star, not in Figure 3 and 4. 2: data correspond only to the brightest member of the group. 3: V observation affected by a cosmic ray, not in Figures 3 and 4. 4: red star, not in Figure 4. 5: integrated magnitude of a double star. 6: probably non-member, far from cluster center, not in Figure 4. -------------------------------------------------------------------------------- Table2 : Spectral classification and absolute magnitudes of the brightest stars in NGC 346 ----------------------------------------------------------------------------- Star Spectral Source Mv Remarks Type ----------------------------------------------------------------------------- 25 O8.5 III a,c -6.6 No. 2 in a 26 O4 III(f) a -7.1 No. 1 in a 28 O5-6: V: c -5.4 Only 1 weak spectrum 29 O3 III(f) b,c -6.1 No. 3 in b 30 O5-6 V b,c -5.9 No. 4 in b 32 O4-5 V c -5.5 ----------------------------------------------------------------------------- a: Walborn N.R., 1978, Ap.J. (Letters), 224, L133 b: Walborn N. R. and Blades J.C., 1986, Ap.J. (Letters), 304, L17 c: This study. ----------------------------------------------------------------------------- Historical Notes: Keupunched at CDS
(End) Marie-Jose Wagner, Patricia Bauer [CDS] 02-Mar-1995
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