J/ApJ/782/59 Abundances of 8 RR Lyrae subclass C variable stars (Govea+, 2014)
The chemical compositions of RR Lyrae type C variable stars.
Govea J., Gomez T., Preston G.W., Sneden C.
<Astrophys. J., 782, 59 (2014)>
=2014ApJ...782...59G 2014ApJ...782...59G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, variable ; Radial velocities ; Abundances
Keywords: astrochemistry - stars: abundances - stars: atmospheres -
stars: horizontal-branch - stars: variables: general -
stars: variables: RR Lyrae
Abstract:
We present a detailed chemical abundance study of eight RR Lyrae
variable stars of subclass c (RRc). The target RRc stars chosen for
study exhibit "Blazhko-effect" period and amplitude modulations to
their pulsational cycles. Data for this study were gathered with the
echelle spectrograph of the 100 inch du Pont telescope at Las Campanas
Observatory. Spectra were obtained throughout each star's pulsation
cycle. Atmospheric parameters--effective temperature, surface gravity,
microturbulent velocity, and metallicity--were derived at multiple
phase points. We found metallicities and element abundance ratios to
be constant within observational uncertainties over the pulsational
cycles of all stars. Moreover, the α-element and Fe-group
abundance ratios with respect to iron are consistent with other
horizontal-branch members (RRab, blue and red non-variables). Finally,
we have used the [Fe/H] values of these eight RRc stars to anchor the
metallicity estimates of a large-sample RRc snapshot spectroscopic
study being conducted with the same telescope and instrument
combination employed here.
Description:
We chose 10 candidate RR Lyrae variable stars of subclass c (RRc)
stars for spectroscopic observation. Many of these stars were first
identified as RRc variables by the All Sky Automated Survey (ASAS) of
Pojmanski 2003 (cat. II/264). The target star list included ASAS
144154-0324.7 and ASAS 204440-2402.7. But our spectroscopic study
suggest that these two stars are probably W UMa binaries instead of RR
Lyrae stars
Our spectra were obtained with the echelle spectrograph of the du Pont
2.5m telescope at the Las Campanas Observatory. Four observing runs
during 2009-2010 were partly devoted to this project. The spectrograph
was used with the 1.5*4'' entrance slit, which translates to a
resolving power of R=λ/Δλ∼27000 at the MgI b lines
near 5180Å. The total continuous wavelength coverage of the spectra
was 3500-9000Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 77 8 Photometric data for the program stars
table2.dat 55 147 Spectroscopic data
table4.dat 63 47 Model atmosphere parameters and Fe abundances
table5.dat 122 47 Abundance ratios [X/Fe] for elements Na through Ti
table6.dat 91 47 Abundance ratios [X/Fe] for elements Cr through Ba
table7.dat 114 8 Average abundances
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See also:
II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-2005)
J/ApJS/197/29 : Chemical compositions of 11 RR Lyrae (For+, 2011)
J/MNRAS/377/1263 : Multiperiodic RR Lyrae in ASAS catalog (Szczygiel+, 2007)
J/AJ/110/2319 : Abundances in RR Lyr variables (Clementini+ 1995)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- ASAS ASAS identifier of the star (HHMMSS+DDMM.m)
15- 22 A8 --- Name Variable name
24- 28 F5.2 mag Vmin [10.5/12.7] Minimum V band magnitude (1)
30- 34 F5.2 mag Vmax [10.7/13.1] Maximum V band magnitude (1)
36- 39 F4.2 mag V-K [0.5/0.8] (V-K) color index from ASAS database
41- 49 F9.7 d Per [0.25/0.33] Period from Szczygiel & Fabrycky
2007 (cat. J/MNRAS/377/1263)
51 A1 --- f_Per [g] Star not included in Szczygiel & Fabrycky
2007 (cat. J/MNRAS/377/1263) (2)
53- 58 F6.2 d Pbl [-11.8/10.9]? Blazhko period from Szczygiel &
Fabrycky 2007 (cat. J/MNRAS/377/1263) (3)
60- 66 F7.2 d T0 [1869.7/2174.7] Epoch of light minimum (from
our study)
68- 77 A10 --- Class ASAS suggested stellar classification (4)
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Note (1): Estimated from the ASAS database.
Note (2): Its pulsational period was determined from our radial velocity data.
Note (3): A negative value of the Blazhko period means that the additional
frequency is smaller than the main pulsation frequency.
Note (4): Classification based on light curve appearance and defined as follows:
RRC = RR Lyrae type C;
EC = Eclipsing binary;
ESD = Eclipsing subdwarf.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Star identifier (abbreviated ASAS name)
10 A1 --- f_Star [a] Phase excluded from analysis
12- 20 F9.4 d HJD [4903/5462] Heliocentric Julian Date
(HJD-2450000.0)
22- 26 F5.3 --- Phase [0/1] Phase Φ (1)
28- 34 F7.2 km/s RV [-177/366] Radial velocity
36- 39 F4.2 --- <Phase> [0/1]? Mean phase <Φ>
41- 46 F6.1 km/s [-173/366]? Mean radial velocity
48 I1 --- Bin [2/6]? Bin size
50- 51 I2 --- S/N1 [14/94]? Signal-to-Noise in 4020-4040Å
region (2)
53- 55 I3 --- S/N2 [52/173]? Signal-to-Noise in 5560-5580Å
region (2)
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Note (1): Determined from the period given by Szczygiel & Fabrycky 2007
(cat. J/MNRAS/377/1263) (see our Table1).
Note (2): S/N ratio presented is obtained from coadded spectrum.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Star Star identifier (abbreviated ASAS name)
10- 14 F5.3 --- Phase [0/1] Mean phase of co-added spectrum
Φ (G1)
16- 19 I4 K Teff [6800/7500] Effective temperature
21- 24 F4.2 [cm/s2] logg [1.8/2.7] Log surface gravity
26- 29 F4.2 km/s Vt [1.5/2.7] Microturbulent velocity
31- 35 F5.2 [Sun] [M/H] [-3/-1.5] Assumed model metallicity
37- 41 F5.2 [Sun] [FeI/H] [-3.1/-1.4] Derived log [FeI/H] abundance
43- 44 I2 --- o_[FeI/H] [4/97] Number of lines for [FeI/H]
46- 49 F4.2 [Sun] e_[FeI/H] [0.09/0.33] Standard deviation of [FeI/H]
51- 55 F5.2 [Sun] [FeII/H] [-3.1/-1.4] Derived log [FeII/H] abundance
57- 58 I2 --- o_[FeII/H] [4/43] Number of lines for [FeII/H]
60- 63 F4.2 [Sun] e_[FeII/H] [0.08/0.39] Standard deviation of [FeII/H]
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Star Star identifier (abbreviated ASAS name)
10- 14 F5.3 --- Phase [0/1] Mean phase of co-added spectrum
Φ (G1)
16- 20 F5.2 [Sun] [Na/Fe] [-0.31/0.83]? Relative abundance ratio [Na/Fe]
22 I1 --- o_[Na/Fe] [1/3]? Number of lines for [Na/Fe]
24- 27 F4.2 [Sun] e_[Na/Fe] [0/0.63]? Sample standard deviation of [Na/Fe]
29- 33 F5.2 [Sun] [Mg/Fe] [-0.1/0.9] Relative abundance ratio [Mg/Fe]
35 I1 --- o_[Mg/Fe] [2/6] Number of lines for [Mg/Fe]
37- 40 F4.2 [Sun] e_[Mg/Fe] [0/0.8] Sample standard deviation of [Mg/Fe]
42- 46 F5.2 [Sun] [Al/Fe] [-1/0.1]? Relative abundance ratio [Al/Fe]
48 I1 --- o_[Al/Fe] [1/2]? Number of lines for [Al/Fe]
50- 53 F4.2 [Sun] e_[Al/Fe] [0/0.6]? Sample standard deviation of [Al/Fe]
55- 59 F5.2 [Sun] [SiI/Fe] [-0.8/1.4]? Relative abundance ratio [SiI/Fe]
61 I1 --- o_[SiI/Fe] [1/2]? Number of lines for [SiI/Fe]
63- 66 F4.2 [Sun] e_[SiI/Fe] [0/1.4]? Sample standard deviation of [SiI/Fe]
68- 72 F5.2 [Sun] [SiII/Fe] [-0.5/1.6]? Relative abundance ratio [SiII/Fe]
74 I1 --- o_[SiII/Fe] [1/5]? Number of lines for [SiII/Fe]
76- 79 F4.2 [Sun] e_[SiII/Fe] [0/0.9]? [SiII/Fe] sample standard deviation
81- 85 F5.2 [Sun] [CaI/Fe] [-0.2/0.7] Relative abundance ratio [CaI/Fe]
87- 88 I2 --- o_[CaI/Fe] [1/14] Number of lines for [CaI/Fe]
90- 93 F4.2 [Sun] e_[CaI/Fe] [0/0.5] Sample standard deviation of [CaI/Fe]
95- 99 F5.2 [Sun] [ScII/Fe] [-0.4/0.4]? Relative abundance ratio [ScII/Fe]
101-104 F4.2 --- o_[ScII/Fe] [1/6]? Number of lines for [ScII/Fe]
106-109 F4.2 [Sun] e_[ScII/Fe] [0/0.8]? [ScII/Fe] sample standard deviation
111-114 F4.2 [Sun] [TiII/Fe] [0.09/0.6] Relative abundance ratio [TiII/Fe]
116-117 I2 --- o_[TiII/Fe] [10/35] Number of lines for [TiII/Fe]
119-122 F4.2 [Sun] e_[TiII/Fe] [0.1/0.5] [TiII/Fe] sample standard deviation
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Star identifier (abbreviated ASAS name)
10- 14 F5.3 --- Phase [0/1] Mean phase of co-added spectrum
Φ (G1)
16- 20 F5.2 [Sun] [CrI/Fe] [-0.6/0.8]? Relative abundance ratio [CrI/Fe]
22 I1 --- o_[CrI/Fe] [1/6]? Number of lines for [CrI/Fe]
24- 27 F4.2 [Sun] e_[CrI/Fe] [0/0.6]? Sample standard deviation of [CrI/Fe]
29- 33 F5.2 [Sun] [CrII/Fe] [-0.2/0.4]? Relative abundance ratio [CrII/Fe]
35 I1 --- o_[CrII/Fe] [1/8]? Number of lines for [CrII/Fe]
37- 40 F4.2 [Sun] e_[CrII/Fe] [0/0.4]? [CrII/Fe] sample standard deviation
42- 45 F4.2 [Sun] [NiI/Fe] [0.44/0.45]? Relative abundance ratio [NiI/Fe]
47 I1 --- o_[NiI/Fe] [1/1]? Number of lines for [NiI/Fe]
49- 52 F4.2 [Sun] e_[NiI/Fe] [0/0]? Sample standard deviation of [NiI/Fe]
54- 58 F5.2 [Sun] [SrII/Fe] [-0.5/1.5]? Relative abundance ratio [SrII/Fe]
60 I1 --- o_[SrII/Fe] [1/2]? Number of lines for [SrII/Fe]
62- 65 F4.2 [Sun] e_[SrII/Fe] [0/1.07]? [SrII/Fe] sample standard deviation
67- 71 F5.2 [Sun] [YII/Fe] [-0.3/0.9]? Relative abundance ratio [YII/Fe]
73 I1 --- o_[YII/Fe] [1/3]? Number of lines for [YII/Fe]
75- 78 F4.2 [Sun] e_[YII/Fe] [0/0.6]? Sample standard deviation of [YII/Fe]
80- 84 F5.2 [Sun] [BaII/Fe] [-0.2/0.6]? Relative abundance ratio [BaII/Fe]
86 I1 --- o_[BaII/Fe] [1/1]? Number of lines for [BaII/Fe]
88- 91 F4.2 [Sun] e_[BaII/Fe] [0/0]? Sample standard deviation of [BaII/Fe]
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Star identifier (abbreviated ASAS name)
10- 13 I4 K Teff [7100/7400] Effective temperature (1)
15- 18 F4.2 [cm/s2] logg [2/2.5] Log surface gravity (1)
20- 23 F4.2 km/s Vt [1.7/2.6] Microturbulent velocity (1)
25- 29 F5.2 [Sun] <[FeI/H]> [-2.9/-1.5] Average FeI/H abundance ratio
31- 35 F5.2 [Sun] <[FeII/H]> [-3/-1.4] Average FeII/H abundance ratio
37- 41 F5.2 [Sun] <[NaI/Fe]> [-0.2/0.6] Average NaI/H abundance ratio
43- 46 F4.2 [Sun] <[MgI/Fe]> [0.2/0.7] Average MgI/H abundance ratio
48- 52 F5.2 [Sun] <[AlI/Fe]> [-0.8/-0.3] Average AlI/Fe abundance ratio
54- 58 F5.2 [Sun] <[SiI/Fe]> [-0.35/0.31] Average SiI/Fe abundance ratio
60- 63 F4.2 [Sun] <[SiII/Fe]> [0.04/1.22] Average SiII/Fe abundance ratio
65- 68 F4.2 [Sun] <[CaI/Fe]> [0.15/0.43] Average CaI/Fe abundance ratio
70- 74 F5.2 [Sun] <[ScII/Fe]> [-0.04/0.26] Average ScII/Fe abundance ratio
76- 79 F4.2 [Sun] <[TiII/Fe]> [0.22/0.43] Average TiII/Fe abundance ratio
81- 85 F5.2 [Sun] <[CrI/Fe]> [-0.19/0.01] Average CrI/Fe abundance ratio
87- 91 F5.2 [Sun] <[CrII/Fe]> [-0.03/0.3]? Average CrII/Fe abundance ratio
93- 96 F4.2 [Sun] <[NiI/Fe]> [0.44/0.45]? Average NiI/Fe abundance ratio
98-102 F5.2 [Sun] <[SrII/Fe]> [-0.1/1.1] Average SrII/Fe abundance ratio
104-108 F5.2 [Sun] <[YII/Fe]> [-0.3/0.35]? Average YII/Fe abundance ratio
110-114 F5.2 [Sun] <[BaII/Fe]> [-0.15/0.4]? Average BaII/Fe abundance ratio
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Note (1): Averaged over all phases.
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Global Notes:
Note (G1): The phase value in row 23 of the table 6 was 0.118. We ignored this
value for VizieR at CDS for consistency with the 0.113 phase value in row
23 of the tables 4 and 5.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 18-Feb-2016