J/AJ/165/154 Spectroscopic study of Ba and CEMP-s stars (Goswami+, 2023)
Spectroscopic Study of Ba and CEMP-s Stars; Mass Distribution of AGB Progenitors
Goswami P.P., Goswami A.
<Astron. J., 165, 154 (2023)>
=2023AJ....165..154G 2023AJ....165..154G
ADC_Keywords: Stars, A-type; Stars, B-type; Stars, G-type; Spectra, optical;
Abundances; Effective temperatures
Keywords: CEMP stars ; Barium stars ; Carbon stars ; Chemically peculiar
stars ; Hertzsprung Russell diagram ; Stellar physics ;
Asymptotic giant branch stars ; Chemical abundances ; S-process
; Spectroscopy
Abstract:
We have performed detailed high-resolution spectroscopic analysis on
seven metal-poor stars (BD+75348, BD+093019, HD238020, HE0319-0215,
HE0507-1653, HE0930-0018, HE1023-1504) and derived their atmospheric
parameters Teff, logg, [Fe/H], and microturbulent velocity (ξ). The
metallicity range is found to be -2.57<[Fe/H]←0.42. The elemental
abundances of 17 light elements and 12 heavy elements are estimated.
We have classified BD+75348 and BD+093019 as strong Ba stars, HD238020
as a mild Ba star, and the remaining four objects as CEMP-s stars. We
have estimated the masses of the stars from Hertzsprung-Russel (HR)
diagram, and, compiling the data of 205 Ba stars from literature,
estimated the mass distribution of Ba stars. We have also estimated
the initial masses of the companion AGBs of the program stars as well
as the masses of the companion AGBs of 159 Ba and 36 CEMP-s stars from
literature, with the help of a parametric-model-based analysis using
FRUITY models. While the primary mass distribution of mild Ba stars
peaks at 3.7M☉, for the strong Ba stars the peak appears at
2.5M☉. We, therefore, propose that the initial masses of the
progenitor AGBs dominantly control the formation of mild and strong Ba
stars. However, a clear overlap, in the range 1.3-4.0M☉, noticed
between the progenitor masses of both the subclasses of Ba stars, may
indicate that other factors, such as the metallicities and the orbital
periods, may also have significant contributions. The progenitor AGBs'
mass distribution of CEMP-s stars is found to peak at 2.03M☉.
Description:
We acquired high-resolution spectra of BD+093019, BD+75348, and
HD238020 using the Hanle Echelle SPectrograph (HESP) attached to the
2m Himalayan Chandra Telescope (HCT) at the Indian Astronomical
Observatory (IAO), Hanle. A 4Kx4K CCD detector with a pixel size of
15µm is used. The wavelength of the spectra covers 3500-10000Å
at a spectral resolution of 60000.
High-resolution spectra (R∼50000) of HE0319-0215, HE0507-1653,
HE0930-0018, and HE1023-1504 are taken from the SUBARU archive 3
acquired using the High Dispersion Spectrograph (HDS) attached to the
8.2m Subaru Telescope. For HE0319-0215, HE0930-0018, and HE1023-1504,
the wavelength coverage of the spectra spans from about 4020 to
6775Å. The wavelength coverage of the spectra of HE0507-1653 spans
from 4090 to 6870Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 102 7 Basic data for the program stars
table3.dat 38 7 Radial velocities of the program stars
table4.dat 103 207 Equivalent widths of Fe-lines used for deriving
atmospheric parameters
table6.dat 103 196 Equivalent widths of Fe-lines used for the
calculation of elemental abundances
table13.dat 82 222 Masses of the Ba-stars and initial masses of their
AGB companions
table14.dat 51 36 Initial masses of AGB companions of CEMP-s stars
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
V/81 : Taxonomy of Barium Stars (Lu 1991)
J/A+A/275/101 : Chemical evolution of galactic disk I. (Edvardsson+ 1993)
J/A+A/326/722 : HIPPARCOS Ba stars (Mennessier+ 1997)
J/A+A/369/178 : Effective temperatures of carbon-rich stars (Bergeat+, 2001)
J/A+A/375/366 : Carbon stars from the Hamburg/ESO survey (Christlieb+ 2001)
J/A+A/410/527 : Abundances in the Galactic disk (Bensby+, 2003)
J/A+A/415/155 : Oxygen abundances in the Galactic disk (Bensby+, 2004)
J/A+A/418/551 : Galactic disk stars abund. & velocities (Mishenina+, 2004)
J/A+A/454/895 : Abundances of 26 barium stars. I. (Allen+, 2006)
J/AJ/132/85 : Equivalent width of 33 metal-poor RHB (Preston+, 2006)
J/MNRAS/367/1329 : Elemental abundances for 176 stars (Reddy+, 2006)
J/ApJ/655/492 : Equivalent widths of 26 metal-poor stars (Aoki+, 2007)
J/A+A/509/A93 : Carbon-enhanced metal-poor stars (Masseron+, 2010)
J/ApJS/194/35 : Atomic transition probabilities of Mn (Den Hartog+, 2011)
J/MNRAS/427/343 : Infrared excesses of Hipparcos stars (McDonald+, 2012)
J/ApJ/762/26 : Metal-poor stars. II. 190 Galactic halo stars (Yong+, 2013)
J/ApJS/215/20 : Vanadium loggf and transition probabilities (Lawler+, 2014)
J/A+A/571/A47 : Extensive linelist CH stellar atmospheres (Masseron+, 2014)
J/ApJS/211/5 : Improved line data for Swan system 12C13C (Ram+, 2014)
J/ApJS/214/26 : Line lists for CN isotopes transitions (Sneden+, 2014)
J/MNRAS/459/4299 : Barium stars abundances and kinematics (de Castro+, 2016)
J/ApJS/226/1 : Carbon stars from LAMOST DR2 data (Ji+, 2016)
J/A+A/586/A158 : Binary properties of CH and CEMP stars (Jorissen+, 2016)
J/ApJ/821/37 : Abundances of metal-poor star HD 94028 (Roederer+, 2016)
J/A+A/608/A100 : CMD and mass distribution of Ba stars (Escorza+, 2017)
J/A+A/623/A128 : Galactic halo CEMP stars abund. & kinematics (Hansen+, 2019)
J/A+A/626/A127 : Barium and related stars and WD companions (Jorissen+, 2019)
J/A+A/649/A49 : Spectroscopic study of CEMP-(s & r/s) stars (Goswami+, 2021)
J/A+A/645/A61 : Abundances of 25 metal-poor stars (Karinkuzhi+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Star identifier
14- 15 I2 h RAh [3/15] Hour of right ascension (J2000)
17- 18 I2 min RAm Minute of right ascension (J2000)
20- 24 F5.2 s RAs Second of right ascension (J2000)
26 A1 --- DE- [±] Sign of declination (J2000)
28- 29 I2 deg DEd Degree of declination (J2000)
31- 32 I2 arcmin DEm Arcminute of declination (J2000)
34- 38 F5.2 arcsec DEs Arcsecond of declination (J2000)
40- 44 F5.2 mag Bmag [9.34/16.3] B-band magnitude
46- 50 F5.2 mag Vmag [8.49/14.7] V-band magnitude
52- 56 F5.2 mag Jmag [6.9/12.4] J-band magnitude
58- 62 F5.2 mag Hmag [6.51/11.7] H-band magnitude
64- 68 F5.2 mag Kmag [6.38/11.5] K-band magnitude
70- 73 I4 s Texp [1200/2700] Exposure time
75- 76 I2 d Obs.D Observation date, day
78- 79 I2 "month" Obs.M Observation date, month
81- 84 I4 yr Obs.Y [2002/2018] Observation date, year
86- 95 A10 --- Ref Spectrum reference(s)
97- 98 I2 --- S/N4000 [7/70] Signal-to-Noise ratio at 4000Å
100-102 I3 --- S/N6000 [25/200] Signal-to-Noise ratio at 6000Å
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star identifier
14- 20 F7.2 km/s RVel [-258/350] Radial velocity estimates in this work
22- 25 F4.2 km/s e_RVel [0.3/4] Error on RVel
27- 33 F7.2 km/s RVel-G [-233/354]? Gaia DR2 radial velocity
35- 38 F4.2 km/s e_RVel-G [0.1/5]? Error on RVel-G
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.3 0.1nm Wave [4187/6740] Wavelength in Angstroms
10- 14 A5 --- Ion Element identifier FeI or FeII
16- 19 F4.2 eV Elow [0/4.99] Lower excitation energy
21- 26 F6.3 [-] loggf [-4.95/0.52] log oscillator strength
28- 32 F5.1 10-13m BD+75348 [42.2/188.2]? Equivalent width in BD+75-348
34- 37 F4.2 [-] [BD+75348] [6.74/7.48]? Derived abundance in BD+75-348
39- 43 F5.1 10-13m BD+093019 [32.7/197]? Equivalent width in BD+09-3019
45- 48 F4.2 [-] [BD+093019] [6.58/7.23]? Derived abundance in BD+09-3019
50- 54 F5.1 10-13m HD238020 [20.7/222]? Equivalent width in HD238020
56- 59 F4.2 [-] [HD238020] [6.51/7.22]? Derived abundance in HD238020
61- 65 F5.1 10-13m HE03190215 [35.5/1233]? Equivalent width in HE0319-0215
67- 70 F4.2 [-] [HE03190215] [4.76/5.16]? Derived abundance in
HE0319-0215
72- 76 F5.1 10-13m HE05081653 [29.3/180]? Equivalent width in HE0508-1653
78- 81 F4.2 [-] [HE05081653] [5.83/6.22]? Derived abundance in
HE0508-1653
83- 87 F5.1 10-13m HE09300018 [20.2/153]? Equivalent width in HE 0930-0018
89- 92 F4.2 [-] [HE09300018] [5.93/6.3]? Derived abundance in HE0930-0018
94- 98 F5.1 10-13m HE10231504 [29.4/164]? Equivalent width in HE 1023-1504
100-103 F4.2 [-] [HE10231504] [5.61/6.08]? Derived abundance in
HE1023-1504
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.3 0.1nm Wave [4061/6768] Wavelength in Angstroms
10- 14 A5 --- Ion Element identifier
16- 19 F4.2 eV Elow [0/5.61] Lower excitation energy
21- 26 F6.3 [-] loggf [-5.7/0.69] log oscillator strength
28- 32 F5.1 10-13m BD+75348 [23.0/191.2]? Equivalent width in BD+75 348
34- 37 F4.2 [-] [BD+75348] [1.49/7.59]? Derived abundance in BD+75-348
39- 43 F5.1 10-13m BD+093019 [69.7/180]? Equivalent width in BD+093019
45- 48 F4.2 [-] [BD+093019] [2.43/8.31]? Derived abundance in BD+093019
50- 54 F5.1 10-13m HD238020 [8.1/339]? Equivalent width in HD238020
56- 59 F4.2 [-] [HD238020] [0.36/7.38]? Derived abundance in HD238020
61- 65 F5.1 10-13m HE03190215 [21.9/119]? Equivalent width in HE0319-0215
67- 70 F4.2 [-] [HE03190215] [0.01/5.51]? Derived abundance in HE03190215
72- 76 F5.1 10-13m HE05081653 [14.3/149]? Equivalent width in HE0508-1653
78- 81 F4.2 [-] [HE05081653] [1.25/6.81]? Derived abundance in
HE0508-1653
83- 87 F5.1 10-13m HE09300018 [18.5/180]? Equivalent width in HE0930-0018
89- 92 F4.2 [-] [HE09300018] [0.35/6.69]? Derived abundance in HE09300018
94- 98 F5.1 10-13m HE10231504 [29.7/162]? Equivalent width in HE1023-1504
100-103 F4.2 [-] [HE10231504] [1.14/5.67]? Derived abundance in
HE1023-1504
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Byte-by-byte Description of file: table13.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Star identifier (1)
12- 15 I4 K Teff [3609/6440] Effective temperature
17- 20 F4.2 [cm/s2] logg [0.6/4.6] log surface gravity
22- 26 F5.2 [Sun] [Fe/H] [-1.11/0.23] Metallicity
28- 32 F5.2 [-] [ls/Fe] [-0.14/1.75]? log average abundance of light-s
process elements
34- 37 F4.2 [-] [hs/Fe] [0.17/2.13] log average abundance of heavy-s
process elements
39- 46 F8.3 [-] [hs/ls] [-0.37/0.98]? log abundance difference of
heavy-s to light-s process elements
48- 51 F4.2 Msun Mass [0.8/4.5]? Ba star mass
53- 55 F3.1 Msun Massi [1.5/6]? Initial stellar AGB mass
57- 61 F5.2 --- chi2 [0.01/43.2]? Model χ2 value
63- 69 F7.5 --- dil [0.0009/1.91]? Dilution factor
71- 72 I2 --- Nel [4/16]? Number of elements used in analysis
74 A1 --- Type Type of Ba stars
76- 82 A7 --- Ref Reference code (2)
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Note (1): HD 75348 corrected by cds; BD+75 348.
Note (2): References as follows:
1 = Allen & Barbuy, 2006, J/A+A/454/895
2 = de Castro+, 2016, J/MNRAS/459/4299
3 = Yang+, 2016RAA....16...19Y 2016RAA....16...19Y
4 = Karinkuzhi+, 2018A&A...618A..32K 2018A&A...618A..32K
5 = Shejeelammal+, 2020MNRAS.492.3708S 2020MNRAS.492.3708S
6 = This work
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Byte-by-byte Description of file: table14.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Name Star identifier
15- 18 I4 K Teff [4000/6625] Effective temperature
20- 23 F4.2 [cm/s2] logg [0.5/4.3] log surface gravity
25- 29 F5.2 [Sun] [Fe/H] [-3/-1.29] Metallicity
31- 33 F3.1 Msun Massi [1.3/3]? Initial stellar AGB mass
35- 39 F5.2 --- chi2 [0.19/24.8] Model χ2 value
41- 47 F7.5 --- dil [0.001/1.76] Dilution factor
49- 51 I3 --- Nel [4/12] Number of elements used in analysis
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 29-Aug-2023