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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 (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:
FileName Lrecl Records Explanations
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/* 0 99 Individual fits spectra
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
Bytes Format Units Label Explanations
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
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).
Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Star identification number 5- 23 A19 --- 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
Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
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
Acknowledgements: Delphine Russeil, delphine.ruseil(at)lam.fr
(End) Patricia Vannier [CDS] 17-Aug-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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