J/A+A/440/121 K magnitudes of OB stars in UCHIIs (Bik+, 2005)
VLT K-band spectroscopy of massive stars deeply embedded in IRAS sources with
UCHII colours.
Bik A., Kaper L., Hanson M.M., Smits M.
<Astron. Astrophys., 440, 121-137 (2005)>
=2005A&A...440..121B 2005A&A...440..121B
ADC_Keywords: H II regions ; Stars, early-type ; Photometry, infrared
Keywords: stars: early-type - stars: formation - stars: distances -
ISM: HII regions - infrared: stars
Abstract:
We have obtained high resolution (R=10000) K-band spectra of
candidate young massive stars deeply embedded in (ultra-) compact HII
regions (UCHIIs). These objects were selected from a near-infrared
survey of 44 fields centered on IRAS sources with UCHII colours.
Often, the near-infrared counterpart of the IRAS source is a young
embedded cluster hosting massive stars. In these clusters, three types
of objects are identified. The first type (38 objects) consists of
"naked" OB stars whose K-band spectra are dominated by photospheric
emission. We classify the K-band spectra of the OB-type cluster
members using near-infrared classification criteria. A few of them
have a very early (O3-O4 V) spectral type, consistent with a young age
of the embedded clusters. The spectral classification provides an
important constraint on the distance to the embedded cluster.
Description:
K-band spectra were taken of point sources in 31 regions from the
sample of 44 IRAS sources with UCHII colours presented in Kaper et al.
(2005, A&A, submitted). The point sources were selected based on their
position in the colour-magnitude diagram. The brightest and most
reddened sources were selected for follow-up spectroscopy.
Medium-resolution, long-slit (120") K-band spectra were obtained with
ISAAC mounted on Antu (UT1) of ESO's Very Large Telescope (VLT),
Paranal, Chile.
The observations were carried out during a visitor mode run (by LK and
MMH) on March 18-20, 2000, and a service mode run in the period
between May 18 and July 16, 2000.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 70 102 Identification of the OB stars and observing log
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See also:
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS Associated IRAS point-source (HHMMm+DDMM)
12- 15 I4 --- Source [43/6909]? Source number
<[BKH2005] HHMMmnrNNNNA> in Simbad
16 A1 --- m_Source [A] Multiplicity index on Source
17 A1 --- n_Source [+] +: source slightly extended, no point
source photometry was possible
19- 21 A3 --- Class Object classification (1)
23- 26 I4 s Texp Total integration time
28- 30 I3 --- S/N Obtained signal-to-noise ratio
32- 46 A15 --- Std Observed standard star used to remove the
telluric lines
48- 52 F5.2 mag Kmag ? K-band magnitude (2)
54- 57 F4.2 mag e_Kmag ? rms uncertainty on Kmag
59- 60 A2 --- l_J-K [≥ ] Limit flag on J-K
61- 65 F5.2 mag J-K ? J-K colour index (2)
67- 70 F4.2 mag e_J-K ? rms uncertainty on J-K
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Note (1): Class of object as follows:
OB = OB stars
YSO = candidate massive Young Stellar Object (YSO)
NEB = nebular Ultra-Compact HII region (UCHII) radio source counterpart
LT = late-type stars
Note (2): values taken from Kaper et al. (2005, A&A, submitted)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 03-May-2013