J/MNRAS/372/661 XMM view of NGC 6231: OB stars (Sana+, 2006)
An XMM-Newton view of the young open cluster NGC 6231.
II. The OB star population.
Sana H., Rauw G., Naze N., Gosset E., Vreux J.-M.
<Mon. Not. R. Astron. Soc. 372, 661 (2006)>
=2006MNRAS.372..661S 2006MNRAS.372..661S
ADC_Keywords: Clusters, open ; Cross identifications ; Photometry, UBVRI ;
Stars, OB ; Stars, pre-main sequence ; X-ray sources
Keywords: stars: fundamental parameters - stars: early-type -
X-rays: individual: NGC 6231 - X-rays: stars -
open clusters and associations: individual: NGC 6231
Abstract:
In this second paper of the series, we focus on the X-ray properties
of the OB star population of NGC 6231. As a tool for our analysis, we
performed a literature-based census of the OB stars in the field of
view. More than one hundred objects are found, among which 30% can be
associated with an X-ray source. All the O-type stars are detected in
the X-ray domain as soft and reasonably strong emitters. [...] Among
B-type stars, the detection rate is only about 25% in the sub-type
range B0-B4 and remains mostly uniform throughout the different
sub-populations while it drops significantly at later sub-types. The
associated X-ray spectra are harder than those of O-type stars. Our
analysis points towards the emission being rather associated with a
physical (in a multiple system) PMS companion. However, we still
observe a correlation between the bolometric luminosity of the B stars
and the measured X-ray luminosity. [...]
Description:
The present catalogue makes a census of the OB stars in the XMM-Newton
field of view (∼15' radius centered on HD 152248) and summaries the
main properties of these objects. The first seven columns
cross-correlate various identifiers. Col. 6 indicates the associated
X-ray source, if any, using the numbering scheme of Paper I. Col. 8
provides the adopted positions while Cols. 9 and 10 list the V
magnitudes and B-V colours obtained from the SSB06 catalogue. The
adopted visual (Mv) and bolometric (Mbol) absolute magnitudes are
provided in Cols. 11 and 12. The adopted spectral types and the
corresponding references are given in Cols. 13 and 14 while the last
column provides miscellaneous notes about the objects, together with
the related references. The meaning of the abbreviations used is given
at the bottom of the table.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
obcensus.dat 160 106 Census of OB stars in the XMM-Newton FOV
refs.dat 115 30 References
xatlas/* . 37 *Individual PostScripts plots of the EPIC spectra
of the detected OB X-ray source
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Note on xatlas/* : The files are named according to the HD/CPD/Se68 identifier
of the X-ray source. Different colours indicate the spectra from the
different EPIC instruments: MOS1 (black), MOS2 (red), pn (blue).
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See also:
J/A+AS/137/233 : UBVI imaging photometry of NGC 6231 (Baume+, 1999)
J/AJ/115/734 : NGC 6231 UBVRI and Halpha photometry (Sung+ 1998)
J/A+A/454/1047 : XMM view of NGC 6231 open cluster (Sana+, 2006)
Byte-by-byte Description of file: obcensus.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD ?=- HD number
8- 11 I4 --- CPD-41d ?=- CPD-41 number (CPD-41 NNNN in Simbad)
12 A1 --- m_CPD-41d [ABps] Multiplicity index on CPD-41
14- 16 I3 --- Segg ?=- Seggewiss, 1968VeBon..79....1S 1968VeBon..79....1S, number
(NGC 6231 NNN in Simbad)
17 A1 --- u_Segg [?b] Uncertainty flag or multiplicity index
for Segg
19- 21 I3 --- SBL98 ?=- Sung et al., 1998, J/AJ/115/734 number
(Cl* NGC 6231 SBL NNN in Simbad)
22 A1 --- n_SBL98 [+?] Source resolved in SBL98 (1)
24- 26 I3 --- BVF99 ?=- Baume et al., 1999, J/A+AS/137/233
number (Cl* NGC 6231 BVF NNN in Simbad)
27 A1 --- n_BVF99 [+] Note on BVF99
29- 31 I3 --- XSeq ? Internal X-ray ID from PaperI
32 A1 --- f_XSeq [r+?] problem with the X-ray determination (2)
34- 37 I4 --- SSB06 ?=- SSB06 number (Sung et al., 2006, in prep.)
39- 40 I2 h RAh Right Ascension (J2000)
42- 43 I2 min RAm Right Ascension (J2000)
45- 49 F5.2 s RAs Right Ascension (J2000)
51 A1 --- DE- Declination sign (J2000)
52- 53 I2 deg DEd Declination (J2000)
55- 56 I2 arcmin DEm Declination (J2000)
58- 61 F4.1 arcsec DEs Declination (J2000)
63- 68 F6.3 mag Vmag V magnitude
70- 74 F5.3 mag B-V B-V colour index
76- 80 F5.2 mag VMAG Absolute V magnitude
82- 87 F6.2 mag Mbol Bolometric magnitude
89-107 A19 --- SpType Spectral classification
109-119 A11 --- r_SpType Reference for the spectral classification
121-160 A40 --- Notes Individual notes and references (3)
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Note (1): Sartoretti et al., 1998A&A...334..592S 1998A&A...334..592S (SBL98) have resolved
two sources quoted as single by Se68 into several components. In these
cases, we only give the brightest counterpart with a `+' appended to
its SBL98 number
Note (2): the symbols mean:
r = large residuals were observed in the EPIC image at the position
of the early-type star.
+ = symbol appended to the X-ray source number indicates that the
X-ray source position is probably corrupted
(see Sect. 3 of Paper II).
Note (3): Abbreviations as follows:
BCep = beta Cephei
CWB = colliding wind binary
EB = eclipsing binary
nm = non member
SB(O) = spectroscopic binary (with computed orbit)
RVvar = radial velocity variable
SPB = slowly pulsating B-star
Vvar = photometric variable
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Ref Reference code
10- 28 A19 --- BibCode BibCode
30- 50 A21 --- Aut Author's name
55-115 A61 --- Com Comments
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Acknowledgements: Hugues Sana,
References:
Sana et al., Paper I 2006A&A...454.1047S 2006A&A...454.1047S, Cat. J/A+A/454/1047
(End) Hugues Sana [ESO, Chile], Patricia Vannier [CDS] 05-Sep-2006