J/MNRAS/485/1067 Composition of eclipsing close binary systems (Takeda+, 2019)
Compositional differences between the component stars of eclipsing close binary
systems showing chemical peculiarities.
Takeda Y., Han I., Kang D.-I., Lee B.-C., Kim K.-M.
<Mon. Not. R. Astron. Soc., 485, 1067-1084 (2019)>
=2019MNRAS.485.1067T 2019MNRAS.485.1067T (SIMBAD/NED BibCode)
ADC_Keywords: Abundances ; Stars, atmospheres ; Binaries, eclipsing ;
Stars, early-type ; Spectra, optical
Keywords: stars: abundances - stars: atmospheres - binaries: eclipsing -
stars: chemically peculiar - stars: early-type
Abstract:
A spectroscopic study was carried out on the surface chemical
abundances of CNO and several heavier elements in the primary and
secondary components of five eclipsing close binaries around A type
(AR Aur, β Aur, YZ Cas, WW Aur, and RR Lyn) in order to
investigate the nature of chemical differences between both components
(being comparatively slow rotators alike due to tidal
synchronization). Regarding the systems comprising similar components,
β Aur and WW Aur were confirmed to exhibit no compositional
difference between the primary and secondary both showing almost the
same Am anomaly, though the chemical peculiarities in the component
stars of AR Aur show distinct differences (HgMn star and Am star). In
contrast, as to the systems (YZ Cas and RR Lyn) consisting of
considerably different (A and early F) components, the surface
abundances are markedly different between the primary (Am) and
secondary (normal). These observational results may indicate
Teff-dependent characteristics regarding the chemical anomalies of
non-magnetic stars on the upper main sequence: (1) In the effective
temperature range of 10000K≳Teff≳7000K, rotational velocity is the
most important factor for determining the extent of Am peculiarity.
(2) However, the emergence of the Am phenomenon seems to have a lower
Teff limit at ∼7000K, below which no abundance anomaly is observed
regardless of stellar rotation. (3) The transition from Am anomaly
(mild deficiency in CNO) to HgMn anomaly (unusually large N depletion)
is likely to take place as Teff increases from ∼10000K to ∼11000K.
Description:
The observations of our five programme stars (AR Aur, β Aur, YZ
Cas, WW Aur, and RR Lyn) were carried out on 2010 December 14, 15, 16,
18, and 20 by using BOES (the Bohyunsan Observatory Echelle
Spectrograph) attached to the 1.8m reflector at Bohyunsan Optical
Astronomy Observatory. Using 2kx4k CCD (pixel size of
15µmx15µm), this Echelle spectrograph enabled us to obtain
spectra of wide wavelength coverage (from ∼3800Å to ∼9200Å). We
used 200µm fibre corresponding to the resolving power of R∼45000.
The total integration time for one observation (consisting of two to
three successive frames to be co-added) was chosen to be ∼10-60min
depending on the brightness of a target. Each of the programme stars
was observed one to three times in a night with an interval of a few
hours, though the actual frequency differed from star to star. Thus,
as a result of the five-night observations, we could obtain 53 spectra
for these five targets, which consist of 9-11 spectra per star
corresponding to different observational times.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
abund.dat 184 10 Elemental abundances derived in this study
suppl.dat 61 101 Supplementary abundance results of 100 A-type
stars
spec1.dat 25 10000 Spectra in 5347-5402Å range
spec2.dat 25 9990 Spectra in 6127-6182Å range
spec3.dat 25 11990 Spectra in 7436-7503Å range
spec4.dat 25 9990 Spectra in 7746-7803Å range
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Byte-by-byte Description of file: abund.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Star name (1 primary, 2 secondary)
9 A1 --- f_Name [*] Flag on Name (1)
11- 15 I5 K Teff Effective temperature
17- 20 F4.2 [cm/s2] logg Surface gravity
22- 24 F3.1 km/s vt Microturbulence
26- 29 F4.1 km/s vsini Projected rotational velocity (from
7765-7785Å fitting)
31- 34 F4.1 10-4nm EWC53 Equivalent width of C I 5380
36- 40 F5.2 --- DC53 non-LTE correction for C I 5380
42- 46 F5.2 --- [C/H]53 non-LTE C abundance from C I 5380 (2)
48- 51 F4.2 --- e_[C/H]53 Error on [C/H]53 (3)
53- 56 F4.1 10-4nm EWN74 Equivalent width of N I 7468
58- 62 F5.2 --- DN74 non-LTE correction for N I 7468
64- 68 F5.2 --- [N/H]74 non-LTE N abundance from N I 7468 (2)
70- 73 F4.2 --- e_[N/H]74 Error on [N/H]74 (3)
75- 79 F5.1 10-4nm EWO61 Equivalent width of O I 6156-8
81- 85 F5.2 --- DO61 non-LTE correction for O I 6156-8
87- 91 F5.2 --- [O/H]61 non-LTE O abundance from O I 6156-8 (2)
93- 96 F4.2 --- e_[O/H]61 Error on [O/H]61 (3)
98-102 F5.1 10-4nm EWO77 Equivalent width of O I 7771-5
104-108 F5.2 --- DO77 non-LTE correction for O I 7771-5
110-114 F5.2 --- [O/H]77 non-LTE O abundance from O I 7771-5 (2)
116-119 F4.2 --- e_[O/H]77 Error on [O/H]77 (3)
121-125 F5.2 --- [Na/H]61 LTE Na abundance from 6140-6168Å
fitting (2)
127-131 F5.2 --- [Si/H]61 LTE Si abundance from 6140-6168Å
fitting (2)
133-137 F5.2 --- [Ca/H]61 LTE Ca abundance from 6140-6168Å
fitting (2)
139-143 F5.2 --- [Ti/H]53 LTE Ti abundance from 5375-5390Å
fitting (2)
145-149 F5.2 --- [Fe/H]53 LTE Fe abundance from 5375-5390Å
fitting (2)
151-155 F5.2 --- [Fe/H]61 LTE Fe abundance from 6140-6168Å
fitting (2)
157-161 F5.2 --- [Fe/H]74 LTE Fe abundance from 7457-7472Å
fitting (2)
163-167 F5.2 --- [Fe/H]77 LTE Fe abundance from 7765-7785Å
fitting (2)
169-173 F5.2 --- [Fe/H] Average of [Fe/H]53, [Fe/H]61, [Fe/H]74,
and [Fe/H]77
175-178 F4.2 --- e_[Fe/H] Standard deviation of [Fe/H]
180-184 F5.2 --- [Ba/H]61 LTE Ba abundance from 6140-6168Å
fitting (2)
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Note (1): Flag as follows:
* = Regarding the primary star of AR Aur (araur1), the results for EW74 and
[N/H]74 are only the upper limits, because the N I 7468 line could
not be detected at all.
Similarly, the C abundance for this star suffers a considerable
uncertainty because the C I 5380 line is too weak and barely measurable.
Note (2): [X/H] values are the differential abundances relative to the standard
star Procyon (=HD 61421); [X/H] = A(X)star-A(X)procyon, with:
A(C)53_Procyon = 8.694 (for [C/H]53)
A(N)74_Procyon = 8.079 (for [N/H]74)
A(O)61_Procyon = 8.836 (for [O/H]61)
A(O)77_Procyon = 8.881 (for [O/H]77)
A(Na)61_Procyon = 6.369 (for [Na/H]61)
A(Si)61_Procyon = 7.111 (for [Si/H]61)
A(Ca)61_Procyon = 6.182 (for [Ca/H]61)
A(Ti)53_Procyon = 5.105 (for [Ti/H]53)
A(Fe)53_Procyon = 7.500 (for [Fe/H]53)
A(Fe)61_Procyon = 7.480 (for [Fe/H]61)
A(Fe)74_Procyon = 7.691 (for [Fe/H]74)
A(Fe)77_Procyon = 7.376 (for [Fe/H]77)
A(Ba)61_Procyon = 2.266 (for [Ba/H]61)
These abundances (relative to H) are expressed in the usual
normalization of A(H) = 12.00.
Note (3): These abundance uncertainties are the total errors derived by
combining those due to uncertainties in Teff, logg, vt and those due
to photometric uncertainties in EW, as described in Sect. 4.3 of
Takeda et al. (2018PASJ...70...91T 2018PASJ...70...91T).
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Byte-by-byte Description of file: suppl.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Star name (HD NNNNNN)
11- 15 I5 K Teff Effective temperature
17- 20 F4.2 [cm/s2] logg Surface gravity
22- 24 F3.1 km/s vt Microturbulence
26- 29 F4.1 km/s vsini Projected rotational velocity
31- 35 F5.2 --- [Na/H]61 LTE Na abundance from 6146-6168Å fitting
37- 41 F5.2 --- [Si/H]61 LTE Si abundance from 6146-6168Å fitting
43- 47 F5.2 --- [Ca/H]61 LTE Ca abundance from 6146-6168Å fitting
49- 53 F5.2 --- [Ti/H]53 LTE Ti abundance from 5375-5390Å fitting
55- 59 F5.2 --- [Fe/H]61 LTE Fe abundance from 6146-6168Å fitting
61 A1 --- Hyades [H] Indicates if the star is a Hyades star
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Byte-by-byte Description of file: spec1.dat spec2.dat spec3.dat spec4.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Name Star name
9- 17 F9.4 0.1nm lambda Wavelength
19- 25 F7.5 --- Flux Continuum-normalized residual flux
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History:
From electronic version of the journal
References:
Takeda et al., Paper I 2018PASJ...70...91T 2018PASJ...70...91T
(End) Ana Fiallos [CDS] 14-Sep-2022