J/MNRAS/400/1479 RV catalogue of O-type stars in NGC 6611 (Sana+, 2009)
The massive star binary fraction in young open clusters.
II. NGC 6611 (Eagle Nebula).
Sana H., Gosset E., Evans C.J.
<Mon. Not. R. Astron. Soc. 400, 1479 (2009)>
=2009MNRAS.400.1479S 2009MNRAS.400.1479S
ADC_Keywords: Clusters, open ; Binaries, spectroscopic ; Stars, O ;
Radial velocities
Keywords: binaries: close - binaries: spectroscopic - stars: early-type -
open clusters and associations: individual: NGC 6611
Abstract:
Based on a set of over 100 medium- to high-resolution optical spectra
collected from 2003 to 2009, we investigate the properties of the
O-type star population in NGC 6611 in the core of the Eagle Nebula
(M16). Using a much more extended data set than previously available,
we revise the spectral classification and multiplicity status of the
nine O-type stars in our sample. We confirm two suspected binaries and
derive the first SB2 orbital solutions for two systems. We further
report that two other objects are displaying a composite spectrum,
suggesting possible long- period binaries. Our analysis is supported
by a set of Monte-Carlo simulations, allowing us to estimate the
detection biases of our campaign and showing that the latter do not
affect our conclusions. The absolute minimal binary fraction in our
sample is fmin=0.44 but could be as high as 0.67 if all the binary
candidates are confirmed. As in NGC 6231 (see Paper I, Sana et al.,
Cat. J/MNRAS/386/447), up to 75% of the O star population in NGC 6611
are found in an O+OB system, thus implicitly excluding random pairing
from a classical IMF as a process to describe the companion
association in massive binaries. No statistical difference could be
further identified in the binary fraction, mass-ratio and period
distributions between NGC 6231 and NGC 6611, despite the difference
in age and environment of the two clusters.
Description:
Journal of the spectroscopic observations of the NGC6611 O-type stars
studied in the present paper. The two header lines indicate the
considered spectral lines and the adopted rest wavelength (in
Angstroms). The first column indicates the object considered. The
second and third ones gives the heliocentric Julian dates at
mid-exposure and the code of the instrumental setup. The following
columns provide the heliocentric RVs (expressed in km/s) using various
spectral lines.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 49 12 Star list
table3.dat 123 117 RV data for O stars in NGC 6611
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See also:
J/MNRAS/386/447 : RV catalogue of O-type stars in NGC 6231 (Sana+, 2008)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Star name
11 A1 --- m_Name [psc] Component (primary/secondary/composite)
16- 17 I2 h RAh Simbad right ascension (J2000) of the system
19- 20 I2 min RAm Simbad right ascension (J2000) of the system
22- 25 F4.1 s RAs Simbad right ascension (J2000) of the system
27 A1 --- DE- Simbad declination sign (J2000) of the system
28- 29 I2 deg DEd Simbad declination sign (J2000) of the system
31- 32 I2 arcmin DEm Simbad declination sign (J2000) of the system
34- 35 I2 arcsec DEs Simbad declination sign (J2000) of the system
39- 49 A11 --- SpType Spectral type from table4 of the paper
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Star name
11 A1 --- m_Name [psc] Component (primary/secondary/composite)
13- 25 F13.5 d HJD Heliocentric Julian Date
27 A1 --- Inst [a-e] Instrument Setup Code (1)
30- 35 F6.1 km/s 4026 ?=- RV measured on HeI4026 (r.w. 4026.072)(2)
38- 43 F6.1 km/s 4089 ?=- RV measured on SiIV4089 (r.w. 4088.863)(2)
46- 51 F6.1 km/s 4144 ?=- RV measured on HeI4144 (r.w. 4143.759)(2)
54- 59 F6.1 km/s 4388 ?=- RV measured on HeI4388 (r.w. 4387.928)(2)
62- 67 F6.1 km/s 4471 ?=- RV measured on HeI4471 (r.w. 4471.512)(2)
70- 75 F6.1 km/s 4481 ?=- RV measured on MgII4481 (r.w. 4481.228)(2)
78- 83 F6.1 km/s 4542 ?=- RV measured on HeII4542 (r.w. 4541.590)(2)
86- 91 F6.1 km/s 4686 ?=- RV measured on HeII5686 (r.w. 4685.682)(2)
94- 99 F6.1 km/s 4921 ?=- RV measured on HeI4921 (r.w. 4921.929)(2)
102-107 F6.1 km/s 5412 ?=- RV measured on HeII5412 (r.w. 5411.620)(2)
110-115 F6.1 km/s 5876 ?=- RV measured on HeI5876 (r.w. 5875.620)(2)
118-123 F6.1 km/s 7065 ?=- RV measured on HeI7065 (r.w. 7065.190)(2)
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Note (1): Instrument Setup Code as follows:
a = ESO2.2m + FEROS
b = VLT + UVES
c = VLT + FLAMES-UVES
d = VLT + FLAMES-GIRAFFE
e = WHT + ISIS
Note (2): r.w.: rest wavelength (in Angstroms) adopted to compute the RVs
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Acknowledgements:
Hugues Sana, H.Sana(at)uva.nl
References:
Sana et al., 2001A&A...370..121S 2001A&A...370..121S (HD 152248)
Sana et al., 2003A&A...405.1063S 2003A&A...405.1063S (CPD-41 7742)
Sana et al., 2006MNRAS.371...67S 2006MNRAS.371...67S (HD152219)
Sana et al., 2007ApJ...659.1582S 2007ApJ...659.1582S (CPD -41 7733)
Sana et al., 2008NewA...13..202S 2008NewA...13..202S (HD 152218)
(End) Hugues Sana [ESO, Chile], Patricia Vannier [CDS] 19-Nov-2009