J/AJ/146/70 Spectroscopy of W UMa-type binary stars (Rucinski+, 2013)
Spectroscopic metallicity determinations for W UMa-type binary stars.
Rucinski S.M., Pribulla T., Budaj J.
<Astron. J., 146, 70 (2013)>
=2013AJ....146...70R 2013AJ....146...70R
ADC_Keywords: Binaries, eclipsing ; Space velocities ; Reddening ; Abundances ;
Radial velocities ; Proper motions
Keywords: methods: observational - stars: abundances - techniques: spectroscopic
Abstract:
This study is the first attempt to determine the metallicities of
W UMa-type binary stars using spectroscopy. We analyzed about 4500
spectra collected at the David Dunlap Observatory. To circumvent
problems caused by the extreme spectral line broadening and blending
and by the relatively low quality of the data, all spectra were
subject to the same broadening function (BF) processing to determine
the combined line strength in the spectral window centered on the Mg I
triplet between 5080Å and 5285Å. All individual integrated BFs
were subsequently orbital-phase averaged to derive a single
line-strength indicator for each star. The star sample was limited to
90 W UMa-type (EW) binaries with the strict phase-constancy of colors
and without spectral contamination by spectroscopic companions. The
best defined results were obtained for an F-type sub-sample
(0.32<(B-V)0<0.62) of 52 binaries for which integrated BF strengths
could be interpolated in the model atmosphere predictions. The
logarithmic relative metallicities, [M/H], for the F-type sub-sample
indicate metal abundances roughly similar to the solar metallicity,
but with a large scatter which is partly due to combined random and
systematic errors. Because of the occurrence of a systematic color
trend resulting from inherent limitations in our approach, we were
forced to set the absolute scale of metallicities to correspond to
that derived from the m1index of the Stromgren uvby photometry for
24 binaries of the F-type sub-sample. The trend-adjusted metallicities
[M/H]1 are distributed within -0.65<[M/H]1<+0.50, with the spread
reflecting genuine metallicity differences between stars. One half of
the F-sub-sample binaries have [M/H]1within -0.37<[M/H]1<+0.10, a
median of -0.04 and a mean of -0.10, with a tail toward low
metallicities, and a possible bias against very high metallicities. A
parallel study of kinematic data, utilizing the most reliable and
recently obtained proper motion and radial velocity data for 78
binaries of the full sample, shows that the F-type sub-sample binaries
(44 stars with both velocities and metallicity determinations) have
similar kinematic properties to solar-neighborhood, thin-disk dwarfs
with space velocity component dispersions: σU=33km/s,
σV=23km/s and σW=14km/s. FU Dra with a large spatial
velocity, Vtot=197km/s and [M/H]1=-0.6±0.2, appears to be the
only thick-disk object in the F-type sub-sample. The kinematic data
indicate that the F-type EW binaries are typical, thin-disk population
stars with ages about 3-5.5Gyr. The F-type binaries that appear to be
older than the rest tend to have systematically smaller mass ratios
than most of the EW binaries of the same period.
Description:
The main data source for the present investigation is the
spectroscopic radial velocity survey of close binaries conducted
during the last decade of the David Dunlap Observatory (DDO)'s
existence, in the years 1998-2008. The spectral window used during the
DDO RV program was centered on the 5184Å line of the neutral
magnesium triplet "b" at 5167.32, 5172.68, and 5183.60Å. The
spectral resolving power of the spectra varied within R=10000-17000.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 221 22 The David Dunlap Observatory (DDO) spectroscopic survey
table3.dat 52 90 Basic assumed parameters for the analyzed EW binaries
table5.dat 83 90 Measured combined line strengths and metallicities
table7.dat 60 65 Kinematic input data
table8.dat 52 78 Space velocity components
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See also:
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
J/AJ/137/3655 : Radial velocities of 8 close binaries (Pribulla+, 2009)
J/AJ/137/3646 : Radial velocities of 10 close binaries (Pribulla+, 2009)
J/AJ/136/586 : Radial velocities of 10 close binaries (Rucinski+, 2008)
J/AJ/133/1977 : Radial velocities of 10 close binaries (Pribulla+, 2007)
J/AJ/132/769 : Radial velocities of 10 close binaries (Pribulla+, 2006)
J/MNRAS/357/497 : Kinematics of W UMa-type binaries (Bilir+, 2005)
J/AJ/130/767 : Radial velocities of close binary stars (Rucinski+, 2005)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- D1 Paper number in the DDO series
4- 22 A19 --- BibCode Bibliographic code
24- 43 A20 --- Aut Author's name
45- 62 A18 --- Cat VizieR catalog
64-221 A158 --- System Binary systems
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- D1 [1/18] Paper number in the DDO series (table1)
3 A1 --- --- [:]
4- 5 I2 --- D2 [1/20] Successive star number within the paper
7- 15 A9 --- Name Star name
17- 22 F6.4 d Per [0.2207/1.0559] Period
24- 28 F5.2 mag Vmag V band magnitude at maximum
30- 33 F4.2 mag B-V The (B-V) color index
35- 38 F4.2 mag e_B-V Uncertainty in B-V
39 A1 --- f_B-V [T] Color from the Tycho-2 Catalog (cat. I/259)
41- 44 F4.2 mag E(B-V) Color excess
46- 48 I3 pc Dist Distance
50- 52 I3 pc e_Dist Uncertainty in Dist
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- D1 [1/18] Paper number in the DDO series (table1)
3 A1 --- --- [:]
4- 5 I2 --- D2 [1/20] Successive number within the DDO paper
7- 15 A9 --- Name Star name
17 A1 --- Gr [BFR] Group to which binary belongs (1)
19- 21 I3 --- Np [4/131] Number of phase points (2)
23- 28 F6.3 [-] logS Log of mean Broadening Function strength
(see section 3)
30- 34 F5.3 [-] e_logS Uncertainty in logS
(evaluated from the phase scatter)
36- 40 F5.3 [-] s_logS Assumed, combined error of logS (Appendix A3)
42- 47 F6.2 10-3 delta Measured shift in BF baseline (δ) (3)
49- 52 F4.2 10-3 e_delta Uncertainty in delta (3)
54- 58 F5.2 [Sun] [M/H]r Raw determination of the metallicity
59 A1 --- f_[M/H]r [e] extrapolated metallicity (4)
61- 67 F7.2 [Sun] [M/H]m ?=-999 Metallicity from Stromgren m1 index
69- 75 F7.2 [Sun] [M/H] ?=-999 Trend-corrected metallicity
76 A1 --- f_[M/H] [e] extrapolated metallicity (4)
78- 82 F5.2 [Sun] e_[M/H] Assumed final error in the metallicity
83 A1 --- n_[M/H] [e] extrapolated metallicity error
(repetition of f_[M/H])
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Note (1): Groups are as follows:
B = Blue ((B-V)0≤0.32);
F = F-type (0.32<(B-V)0≤0.62);
R = Red ((B-V)0>0.62).
Note (2): Used for averaging of independent orbital points.
Note (3): Multiplied by 103 for more convenient formatting. Such shift
represents missing information on the real continuum level.
Note (4): e = Metallicity determined through extrapolation beyond the model
grid and thus entirely unreliable (see Section 5.3 for more details).
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- D1 [1/18] Paper number in the DDO series (table1)
3 A1 --- --- [:]
4- 5 I2 --- D2 [1/10] Successive number within the DDO paper
7- 15 A9 --- Name Star name
17- 22 I6 --- HIP Hipparcos mission number
24- 29 F6.2 km/s RV Center-of-mass radial velocity (1)
31- 34 F4.2 km/s e_RV Uncertainty in RV
36- 42 F7.2 mas/yr pmRA Proper motion along Right Ascension (2)
44- 47 F4.2 mas/yr e_pmRA Uncertainty in pmRA
49- 55 F7.2 mas/yr pmDE Proper motion along Declination (2)
57- 60 F4.2 mas/yr e_pmDE Uncertainty in pmDE
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Note (1): From the David Dunlap Observatory (DDO) survey.
Note (2): From the new reductions of the Hipparcos data by van Leeuwen (2007,
cat. I/311).
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Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- D1 [1/18] Paper number in the DDO series (table1)
3 A1 --- --- [:]
4- 5 I2 --- D2 [1/10] Successive number within the DDO paper
7- 15 A9 --- Name Star name
17- 21 F5.1 km/s Uvel New U component space velocity
23- 26 F4.1 km/s e_Uvel Uncertainty in Uvel
27 A1 --- f_Uvel [B] Origin of Uvel (1)
29- 34 F6.1 km/s Vvel New V component space velocity
36- 39 F4.1 km/s e_Vvel Uncertainty in Vvel
40 A1 --- f_Vvel [B] Origin of Vvel (1)
42- 46 F5.1 km/s Wvel New W component space velocity
48- 51 F4.1 km/s e_Wvel Uncertainty in Wvel
52 A1 --- f_Wvel [B] Origin of Wvel (1)
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Note (1): Space velocity from Bilir et al. 2005 (J/MNRAS/357/497).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 08-Jul-2014