J/A+A/607/A86 NGC 6334 and NGC 6357 OB stars spectra (Russeil+, 2017)
NGC 6334 and NGC 6357: Insights from spectroscopy of their OB star populations.
Russeil D., Adami C., Bouret J.C., Herve A., Parker Q.A., Zavagno A.,
Motte F.
<Astron. Astrophys. 607, A86 (2017)>
=2017A&A...607A..86R 2017A&A...607A..86R (SIMBAD/NED BibCode)
ADC_Keywords: H II regions ; Spectral types ; Stars, ages ; Stars, distances ;
Stars, OB
Keywords: stars: distances - HII regions - ISM: individual objects: NGC 6334 -
ISM: individual objects: NGC 6357
Abstract:
The formation of high mass stars is still debated. For this reason,
several projects, as the Herschel-HOBYS are focussed on the study of
the earliest phases of massive star formation. As a result, massive
star-forming complexes such as NGC 6334 and NGC 6357 have been
observed in the far-infrared to study their massive dense cores where
massive stars are expected to form. However, to better characterise
the environment of these cores we need to understand the previous
massive star formation history. To better characterize the environment
of these massive dense cores we propose to study the previous high
mass star formation and how these stars act on their environment. This
study is based on spectral classification of the OB stars identified
towards NGC 6334 and NGC 6357 with spectra taken with the AAOmega
spectrograph on the Anglo-Australian Telescope (AAT). From the
subsequent spectral classification of 109 stars across these regions
we have been able to evaluate the following: distance, age, mass,
global star-forming efficiency (SFE) and star-formation rate (SFR) of
the regions. The physical conditions of the ionised gas for both
complexes was also derived. We confirm that NGC 6334 and NGC 6357
belong to the Saggitarius-Carina arm which, in this direction, extends
from 1kpc to 2.2kpc. From the location of the stars in
Hertzprung-Russell diagram we show that stars older than ∼10Myr are
broadly spread across these complexes while younger stars are mainly
located in the H ii regions and stellar clusters. Our data also
suggests that some of the young stars can be considered as runaway
stars. We evaluate a SFE of 0.019 and 0.021 and a SFR of
1.1x103M_☉/Myr^ and 1.7x103M☉/Myr for NGC 6334 and NGC
6357 respectively. We note that 25 OB stars have X-ray counterparts,
most of them belonging to NGC 6357. This suggests that molecular
clouds in NGC 6357 is more impacted by X-ray flux and stellar winds
than for NGC 6334. Finally, from analysis of nebular lines (Hα,
[NII] and [SII]) from spectra from several regions of ionised gas, we
confirm that the filaments in NGC 6357 are shock heated.
Description:
Stellar parameters, observed properties and spectra for the O-B3 star
sample.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 123 109 Properties of the 109 O-B3 stars
tablea1.dat 93 109 Additional information for the star sample
list.dat 41 99 Spectra (3800-5000Å) of the O-B3 stars
sp/* . 99 Individual fits spectra
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See also:
J/A+A/538/A142 : OB stars in NGC 6334 and NGC 6357 (Russeil+, 2012)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Star identification number
4 A1 --- XFlag [*] Asterisk if X-Ray counterpart (1)
6- 7 I2 h RAh Right ascension (J2000.0)
9- 10 I2 min RAm Right ascension (J2000.0)
12- 15 F4.1 s RAs Right ascension (J2000.0)
17 A1 --- DE- Declination sign (J2000.0)
18- 19 I2 deg DEd Declination (J2000.0)
21- 22 I2 arcmin DEm Declination (J2000.0)
24- 27 F4.1 arcsec DEs Declination (J2000.0)
29- 36 A8 --- SpType Spectral type (2)
38- 43 F6.3 mag Vmag Band V magnitude (3)
45- 49 F5.3 mag e_Vmag Band V magnitude uncertainty
51- 56 F6.3 mag Bmag Band B magnitude (3)
58- 62 F5.3 mag e_Bmag Band B magnitude uncertainty
64- 69 F6.3 mag Umag Band U magnitude (3)
71- 75 F5.3 mag e_Umag Band U magnitude uncertainty
77- 81 F5.2 mag AV Extinction
83- 86 F4.2 mag e_AV Extinction uncertainty
88- 92 F5.2 kpc d Distance
94- 97 F4.2 kpc e_d Distance uncertainty
99-102 F4.1 Msun Mass Evaluated stellar Mass
104-106 F3.1 [yr] logAge Evaluated stellar age
108-123 A16 --- 2MASS 2MASS designation
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Note (1): Stars marked with a "*" indicate they have an X-Ray counterpart.
Note (2): Stars with no luminosity class are classified from the red part of
their spectrum (we assume they are dwarf stars).
Note (3): The UBV photometry is from Russeil et al. (2012, Cat. J/A+A/538/A142).
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Star identification number
5- 23 I19 --- GAIA ? GAIA designation
25 I1 --- fl-GAIA [0/1]? GAIA duplicate flag
27- 32 F6.3 mag Gmag ? GAIA mean g-band magnitude
34- 49 A16 --- 2MASS 2MASS designation
51- 54 F4.1 arcsec fl-prox ? 2MASS prox. flag
56- 69 A14 --- Region Region name
71- 93 A23 --- Ident Other stellar name
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Star identification number
5- 11 F7.3 deg RAdeg Right ascension (J2000)
13- 19 F7.3 deg DEdeg Declination (J2000)
21- 41 A21 --- FileName Name of the FITS file in subdirectory sp
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Acknowledgements:
Delphine Russeil, delphine.ruseil(at)lam.fr
(End) Patricia Vannier [CDS] 17-Aug-2017