J/A+A/466/277 VLT-FLAMES survey of massive stars (Hunter+, 2007)
The VLT-FLAMES survey of massive stars: surface chemical compositions of
B-type stars in the Magellanic Clouds.
Hunter I., Dufton P.L., Smartt S.J., Ryans R.S.I., Evans C.J., Lennon D.J.,
Trundle C., Hubeny I., Lanz T.
<Astron. Astrophys., 466, 277-300 (2007)>
=2007A&A...466..277H 2007A&A...466..277H
ADC_Keywords: Equivalent widths ; Stars, B-type ; Abundances
Keywords: stars: early-type - stars: atmospheres - stars: abundances -
Magellanic Clouds - Galaxies: abundances -
open clusters and associations: individual: NGC 6611, N11 and NGC 346
Abstract:
We present an analysis of high-resolution FLAMES spectra of
approximately 50 early B-type stars in three young clusters at
different metallicities, NGC 6611 in the Galaxy, N 11 in the Large
Magellanic Cloud (LMC) and NGC 346 in the Small Magellanic Cloud
(SMC). Using the TLUSTY non-LTE model atmospheres code, atmospheric
parameters and photospheric abundances (C, N, O, Mg and Si) of each
star have been determined. These results represent a significant
improvement on the number of Magellanic Cloud B-type stars with
detailed and homogeneous estimates of their atmospheric parameters and
chemical compositions. The relationships between effective temperature
and spectral type are discussed for all three metallicity regimes,
with the effective temperature for a given spectral type increasing as
one moves to a lower metallicity regime. Additionally the difficulties
in estimating the microturbulent velocity and the anomalous values
obtained, particularly in the lowest metallicity regime, are
discussed. Our chemical composition estimates are compared with
previous studies, both stellar and interstellar with, in general,
encouraging agreement being found.
Description:
Files table3.dat, table4.dat and table5.dat contain the
equivalent widths and abundances estimates of the observed metal lines
for B-type stars in NGC 6611, N11 and NGC 346 respectively. The
equivalent widths of the spectral lines have been measured using the
line fitting program ELF in the spectral analysis package DIPSO
(Howarth et al., 1994, Starlink User Note, No. 50.15). The nitrogen
equivalent widths and abundances are upper limits for objects N11-037,
N11-047, N11-101, NGC 346-029, NGC 346-039, NGC 346-040, NGC 346-043,
NGC 346-044 and NGC 346-075.
table6.dat contains details of the adopted atomic data for the
absorption lines considered in this analysis. Model atoms are
discussed in Lanz & Hubeny (2003ApJS..146..417L 2003ApJS..146..417L) and Allende Prieto et
al. (2003ApJS..147..363A 2003ApJS..147..363A), see Dufton et al. (2005, Cat.
J/A+A/434/1125) for further details. Note, the loggf values of the
Si II lines at 4128 and 4131 angstroms have been updated to include
improved atomic data (A. Korn, private communication).
Objects:
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RA (2000) DE Designation(s) (files)
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18 18 48. -13 49 00 NGC 6611 = M 16 (table3)
04 57 16.2 -66 23 18 IC 2116 = LHA 120-N 11A (table4)
00 59 18.0 -72 10 48 NGC 346 = LHA 115-N 66A (table5)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 37 49 Star positions
table3.dat 37 285 Equivalent Width Measurements and line-by-line
abundances for NGC6611 stars
table4.dat 37 1710 Equivalent Width Measurements and line-by-line
abundances for N11 stars
table5.dat 37 798 Equivalent Width Measurements and line-by-line
abundances for NGC346 stars
table6.dat 32 70 Adopted atomic data for the absorption lines
considered in this analysis
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See also:
J/A+A/437/467 : VLT-FLAMES survey of massive stars (Evans+, 2005)
J/A+A/457/265 : VLT-FLAMES Survey of massive Stars (Dufton+, 2006)
J/A+A/456/623 : VLT-FLAMES survey of massive stars (Evans+, 2006)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- VName Variable name
14- 15 I2 h RAh Right ascension (J2000)
17- 18 I2 min RAm Right ascension (J2000)
20- 24 F5.2 s RAs Right ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 37 F5.2 arcsec DEs Declination (J2000)
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Byte-by-byte Description of file: table[345].dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- VName Variable name (1)
14- 19 A6 --- Species Species of the element
21 A1 --- n_Species [B] B indicates a blend of lines
23- 28 F6.1 0.1nm lambda Rest wavelength of the spectral line
30- 32 I3 0.1pm EW ?=- Equivalent width
34- 37 F4.2 [Sun] Abund ?=- Abundance of species, in [X/H]
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Note (1): Corresponding Simbad designations are:
NGC 6611-NNN = Cl* NGC 6611 ESL NNN
N11-NNN = [ELS2006] N11 ESL NNN
NGC 346-NNN = Cl* NGC 346 ESL NNN
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Species Species of the element
8- 14 F7.2 0.1nm lambda Rest wavelength of the spectral line
16- 21 F6.3 [-] loggf Oscillator strength value
23- 32 A10 --- Blends Details of lines considered as blends
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Acknowledgements:
Ian Hunter, i.hunter(at)qub.ac.uk
(End) Ian Hunter [QUB, United Kingdom], Patricia Vannier [CDS] 10-May-2007