J/AJ/151/49 M6 open cluster: star members properties (Kilicoglu+, 2016)
Chemical composition of intermediate-mass star members of the M6 (NGC 6405)
open cluster.
Kilicoglu T., Monier R., Richer J., Fossati L., Albayrak B.
<Astron. J., 151, 49 (2016)>
=2016AJ....151...49K 2016AJ....151...49K (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, UBV ; Radial velocities ;
Effective temperatures ; Stars, masses ; Abundances
Keywords: open clusters and associations: M6 - stars: abundances -
stars: individual: HD 318101
Abstract:
We present here the first abundance analysis of 44 late B-, A-, and
F-type members of the young open cluster M6 (NGC 6405, age about 75 Myr).
Low- and medium-resolution spectra, covering the 4500-5840 Å
wavelength range, were obtained using the FLAMES/GIRAFFE spectrograph
attached to the ESO Very Large Telescopes. We determined the
atmospheric parameters using calibrations of the Geneva photometry and
by adjusting the Hβ profiles to synthetic ones. The abundances
of up to 20 chemical elements, from helium to mercury, were derived
for 19 late B, 16 A, and 9 F stars by iteratively adjusting synthetic
spectra to the observations. We also derived a mean cluster metallicity
of [Fe/H]=0.07±0.03 dex from the iron abundances of the F-type stars.
We find that for most chemical elements, the normal late B- and A-type
stars exhibit larger star-to-star abundance variations than the F-type
stars probably because of the faster rotation of the B and A stars.
The abundances of C, O, Mg, Si, and Sc appear to be anticorrelated
with that of Fe, while the opposite holds for the abundances of Ca,
Ti, Cr, Mn, Ni, Y, and Ba as expected if radiative diffusion is efficient
in the envelopes of these stars. In the course of this analysis, we
discovered five new peculiar stars: one mild Am, one Am, and one Fm star
(HD 318091, CD-32 13109, GSC 07380-01211, CP1), one HgMn star (HD 318126,
CP3), and one He-weak P-rich (HD 318101, CP4) star. We also discovered
a new spectroscopic binary, most likely a SB2. We performed a detailed
modeling of HD 318101, the new He-weak P-rich CP star, using the
Montreal stellar evolution code XEVOL which self-consistently treats
all particle transport processes. Although the overall abundance
pattern of this star is properly reproduced, we find that detailed
abundances (in particular the high P excess) resisted modeling
attempts even when a range of turbulence profiles and mass-loss rates
were considered. Solutions are proposed which are still under
investigation.
Description:
The spectra of 104 objects in the region of M6 were obtained using the
Fibre Large Array Multi Element Spectrograph (FLAMES) instrument with
the GIRAFFE spectrograph attached to the Unit 2 Kueyen of the Very
Large Telescopes at the European Southern Observatory (ESO) by one of
us (L.F.). The instrument settings and target selection were carried
out in the same way as described by Fossati et al. (2011MNRAS.413.1132F 2011MNRAS.413.1132F).
We primarily considered 56 targets with Teff>6100 K and spectra
with S/N∼100, and selected 44 targets to perform a more thorough spectral
analysis considering the membership from 3 criteria: (i) proper
motions, (ii) radial velocity, and (iii) position of the stars in the
Hertzsprung-Russell (HR) diagram (Table 3).
Objects:
--------------------------------------------
RA (ICRS) DE Designation(s)
--------------------------------------------
17 40 20 -32 15.2 M6 = NGC 6405
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 76 44 List of Selected Targets
table4.dat 48 43 Log L/L☉, log Teff , M/M☉, and
Fractional Age (τ) for the Members
table5.dat 72 44 Fundamental Parameters for the Program Stars
table7.dat 136 44 Log(X/H) Absolute Abundances for the M6 Dwarfs
table8.dat 53 44 *Abundances for the M6 Dwarfs
table14.dat 41 31 Radial Velocity Variations
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Note on table8.dat:
Abundances are expressed with respect to the cosmic abundances derived for
young early B stars by Nieva & Przybilla (2012, J/A+A/539/A143).
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See also:
J/A+A/446/949 : Open clusters proper motions based on UCAC2 (Dias+, 2006)
J/A+A/454/171 : CCD Δa-photometry of 8 open clusters (Paunzen+, 2006)
J/AJ/136/118 : Open clusters as galactic disk tracers. I. (Frinchaboy+, 2008)
J/A+A/539/A143 : Nearby B-stars stellar parameters and abundances
(Nieva+, 2012)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Star Star designation
15- 17 A3 --- n_Star [SB2 var] Note on Star (1)
19- 21 I3 --- Num [5/130]? Star identification number from
Rohlfs et al. (1959ZA.....47...15R 1959ZA.....47...15R)
23- 27 F5.2 mag Vmag [8.26/12.69] V-band magnitude
29- 30 I2 % PMemb-D [0/63]? Membership probability from
Dias et al. 2006 (J/A+A/446/949)
32- 35 F4.1 % PMemb-FM [1.1/97.1]? Membership probability from
Frinchaboy & Majewski 2008 (J/AJ/136/118)
37- 42 F6.2 km/s RV-FM [-71.71/55.26]? Radial velocity from
Frinchaboy & Majewski 2008 (J/AJ/136/118)
44- 47 F4.2 km/s e_RV-FM [2.58/7.76]? Uncertainty in RV-FM
49- 54 F6.2 km/s RV [-14.38/6.76]? Radial velocity from this study
56- 60 F5.2 km/s e_RV [0.23/18.18]? Uncertainty in RV
62- 64 A3 --- HR [Yes --- No] HR diagram membership?
66- 68 I3 --- S/N1 [34/653] Signal-to-noise ratio of first
observation
70- 72 I3 --- S/N2 [78/686] Signal-to-noise ratio of second
observation
74- 76 I3 --- S/N3 [51/539] Signal-to-noise ratio of third
observation
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Note (1): Note as follows:
SB2 = The spectra of the star No. 33 reveals that this star is a double-lined
spectroscopic binary (SB2) with components of similar spectral type,
because of the similar intensity of the lines of the two stars. The
effective temperature derived from Geneva photometry indicated an early
F spectral type. We determined the projected rotational velocities of
the two stars using unblended well separated iron lines, obtaining
30±10 km/s and 35±10 km/s. The maximum Vr difference between the
two stars was 170±10 km/s.
var = The star No. 99 presents the largest radial velocity variation
(∼38 km/s) and is therefore likely to be a binary.
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Star Star designation
15- 17 I3 --- Num [5/130]? Star identification number from
Rohlfs et al. (1959ZA.....47...15R 1959ZA.....47...15R)
19- 22 F4.2 [Lsun] logL [0.21/2.49] Log luminosity relative to solar
24- 28 F5.3 [K] logTeff [3.813/4.188] Log effective temperature
30- 33 F4.2 Msun Mass [1.24/4.33] Stellar mass relative to solar
35- 38 F4.2 Msun e_Mass [0.04/0.43] Uncertainty in Mass
40- 43 F4.2 --- tau [0.02/0.65] Fractional stellar age τ
45- 48 F4.2 --- e_tau [0.01/0.17] Uncertainty in tau
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Star Star designation
15 A1 --- n_Star [s] Note on Star (1)
17- 19 I3 --- Num [5/130]? Star identification number from
Rohlfs et al. (1959ZA.....47...15R 1959ZA.....47...15R)
21- 25 I5 K Teff [6045/15864]? Photometric effective temperature
derived from Geneva seven-color photometry
26 A1 --- n_Teff [)] Note on Teff (2)
28- 31 F4.2 [cm/s2] logg [3.22/4.76]? Surface gravity derived from
Geneva seven-color photometry (dex)
33- 37 I5 K TeffF [6500/15400] Final adopted effective
temperature
39- 41 I3 K e_TeffF [100/500] Uncertainty in TeffF
43- 46 F4.2 [cm/s2] loggF [3.50/4.80]? Final adopted surface gravity
(dex)
48- 51 F4.2 [cm/s2] e_loggF [0.10/0.50]? Uncertainty in loggF
52 A1 --- n_loggF [)] Note on loggF (2)
54- 56 F3.1 km/s Vturb [0/2.7]? Derived microturbulent velocity
58- 62 F5.1 km/s vsini [5.1/310]? Projected rotational velocity
64- 67 F4.1 km/s e_vsini [0.5/25]? Uncertainty in vsini
69- 72 A4 --- SpType Spectral type
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Note (1): Note as follows:
s = Spectroscopic binary.
Note (2): Note as follows:
) = Value estimated from Johnson photometry.
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Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Star Star designation
15- 17 I3 --- Num [5/130]? Star identification number from
Rohlfs et al. (1959ZA.....47...15R 1959ZA.....47...15R)
19- 23 F5.2 [-] [He/H] [-1.55/0]? Absolute He abundance
25- 29 F5.2 [-] [C/H] [-3.82/0]? Absolute C abundance
31- 35 F5.2 [-] [O/H] [-3.4/0]? Absolute O abundance
37- 41 F5.2 [-] [Mg/H] [-4.65/0]? Absolute Mg abundance
43- 47 F5.2 [-] [Si/H] [-5.02/0]? Absolute Si abundance
49- 53 F5.2 [-] [P/H] [-4.88/0]? Absolute P abundance
55- 59 F5.2 [-] [S/H] [-5.32/0]? Absolute S abundance
61- 65 F5.2 [-] [Ar/H] [-5.13/0]? Absolute Ar abundance
66- 70 F5.2 [-] [Ca/H] [-6.27/0]? Absolute Ca abundance
72- 76 F5.2 [-] [Sc/H] [-9.41/0]? Absolute Sc abundance
78- 82 F5.2 [-] [Ti/H] [-7.2/0]? Absolute Ti abundance
84- 88 F5.2 [-] [Cr/H] [-6.38/0]? Absolute Cr abundance
90- 94 F5.2 [-] [Mn/H] [-6.7/0]? Absolute Mn abundance
96-100 F5.2 [-] [Fe/H] [-4.84/0]? Absolute Fe abundance
102-106 F5.2 [-] [Ni/H] [-5.84/0]? Absolute Ni abundance
108-112 F5.2 [-] [Y/H] [-9.78/0]? Absolute Y abundance
114-118 F5.2 [-] [Zr/H] [-6.1/0]? Absolute Zr abundance
120-124 F5.2 [-] [Xe/H] [-5.98/0]? Absolute Xe abundance
126-130 F5.2 [-] [Ba/H] [-9.97/0]? Absolute Ba abundance
132-136 F5.2 [-] [Hg/H] [-5.69/0]? Absolute Hg abundance
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Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Star Star designation
15- 17 I3 --- Num [5/130]? Star identification number from
Rohlfs et al. (1959ZA.....47...15R 1959ZA.....47...15R)
19- 23 F5.2 [-] [He/H] [-0.54/0.07]? He abundance
25- 29 F5.2 [-] [C/H] [-0.15/0.6]? C abundance
31- 35 F5.2 [-] [O/H] [-0.16/0.15]? O abundance
37- 41 F5.2 [-] [Mg/H] [-0.21/0.95]? Mg abundance
43- 47 F5.2 [-] [Si/H] [-0.52/0.31]? Si abundance
49- 53 F5.2 [-] [Fe/H] [-0.36/0.32]? Fe abundance
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Byte-by-byte Description of file: table14.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Star Star designation
15- 17 I3 --- Num [5/130]? Star identification number from
Rohlfs et al. (1959ZA.....47...15R 1959ZA.....47...15R)
19- 24 F6.2 km/s RV1 [-11.89/18.31] Radial velocity at MJD 54250.3494
26- 31 F6.2 km/s RV2 [-20.1/-0.37] Radial velocity at MJD 54256.1309
33- 37 F5.2 km/s DRV [0.07/38.41] Radial velocity difference
39- 41 A3 --- Var [Yes No] Radially variable?
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 14-Mar-2018