J/ApJ/934/110 Abundance analysis of 4 HES metal-poor stars (Shejeelammal+, 2022)
Spectroscopic study of four metal-poor carbon stars from the Hamburg/ESO Survey:
on confirming the low-mass nature of their companions.
Shejeelammal J., Goswami A.
<Astrophys. J., 934, 110 (2022)>
=2022ApJ...934..110S 2022ApJ...934..110S
ADC_Keywords: Abundances; Spectra, optical; Stars, carbon; Radial velocities;
Stars, metal-deficient; Equivalent widths
Keywords: Chemical abundances ; Chemically peculiar stars ; Carbon stars
Abstract:
Elemental abundances of extrinsic carbon stars provide insight into
the poorly understood origin and evolution of elements in the early
Galaxy. In this work, we present the results of a detailed
spectroscopic analysis of four potential carbon star candidates from
the Hamburg/ESO Survey (HES): HE 0457-1805, HE 0920-0506, HE1241-0337,
and HE 1327-2116. This analysis is based on the high-resolution
spectra obtained with Mercator/HERMES (R∼86000) and SUBARU/HDS
(R∼50000). Although the abundances of a few elements, such as Fe, C,
and O, are available from medium-resolution spectra, we present the
first ever detailed high-resolution spectroscopic analysis for these
objects. The objects HE 0457-1805 and HE 1241-0337 are found to be
CEMP-s stars, HE 0920-0506 a CH star, and HE 1327-2116 a CEMP-r/s
star. The object HE 0457-1805 is a confirmed binary, whereas the
binary status of the other objects is unknown. The locations of
program stars on the diagram of absolute carbon abundance A(C) versus
[Fe/H] point at their binary nature. We have examined various
elemental abundance ratios of the program stars and confirmed the low-
mass nature of their former AGB companions. We have shown that the
i-process models could successfully reproduce the observed abundance
pattern in HE 1327-2116. The analysis performed for HE 0457-1805,
HE0920-0506, and HE 1241-0337 based on the FRUITY parametric models
confirmed that the surface chemical compositions of these three
objects are influenced by pollution from low-mass AGB companions.
Description:
All the four objects analyzed in this study --HE0457-1805,
HE0920-0506, HE1241-0337, and HE1327-2116-- are selected from the
candidate metal-poor stars identified from the Hamburg/ESO
Objective-prism Survey (HES; Christlieb 2003RvMA...16..191C 2003RvMA...16..191C).
The wavelength-calibrated, high-resolution (R∼50000) spectrum of
HE1241-0337 is taken from the SUBARU/HDS archive
(http://jvo.nao.ac.jp/portal/v2/). The wavelength coverage of this
spectrum is 4100-6850Å with a wavelength gap between 5440 and
5520Å.
The high-resolution (R∼86000) spectra of the objects HE0457-1805,
HE0920-0506, and HE1327-2116 were obtained using the High-Efficiency
and High-Resolution Mercator Echelle Spectrograph (HERMES) attached to
the 1.2m Mercator telescope at the Roque de los Muchachos Observatory
in La Palma, Canary Islands, Spain, operated by the Institute of
Astronomy of the KU Leuven, Belgium.
The HERMES spectra cover the wavelength range 3770-9000Å. Multiple
frames of each object were taken on different nights: 15 frames with
exposures of 1800 and 2100s for HE 0457-1805 during the period
2013-2016, 10 frames with exposures ranging from 750 to 1800s for
HE0910-0506 during 2018-2020, and three frames with exposures of 1200s
for HE 1327-2116 on 2019 January 31 and 2019 February 1.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 89 4 Basic information on the program stars
table2.dat 87 9 Derived atmospheric parameters and radial velocity
of the program stars
table9.dat 70 52 Equivalent widths of Fe lines used for deriving
atmospheric parameters
table10.dat 72 172 Equivalent widths of lines used for deriving
elemental abundances
table11.dat 55 31 Lines used to derive the elemental abundance
from spectral synthesis
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See also:
III/272 : RAVE 4th data release (Kordopatis+, 2013)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+AS/141/371 : Low-mass stars evolutionary tracks (Girardi+, 2000)
J/A+A/354/169 : Metal-poor field stars abundances (Gratton+, 2000)
J/A+A/375/366 : Carbon stars from the Hamburg/ESO survey (Christlieb+ 2001)
J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)
J/AJ/128/1177 : Galactic stellar abundances (Venn+, 2004)
J/A+A/454/895 : Abundances of 26 barium stars. I. (Allen+, 2006)
J/ApJ/652/1585 : Bright metal-poor stars from HES survey (Frebel+, 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/ApJ/658/1203 : Nitrogen-enhanced metal-poor stars (Johnson+, 2007)
J/AJ/133/2464 : Parameters and abundances of nearby giants (Luck+, 2007)
J/A+A/490/769 : Yields from extremely metal-poor stars (Campbell+, 2008)
J/A+A/484/721 : HES survey. IV. Cand. metal-poor stars (Christlieb+, 2008)
J/ApJ/696/797 : Evolution & yields of low-mass AGB stars (Cristallo+, 2009)
J/MNRAS/404/1529 : s-process in low-metallicity stars (Bisterzo+, 2010)
J/ApJ/724/341 : Nucleosynthesis of massive metal-free stars (Heger+, 2010)
J/MNRAS/403/1413 : Updated stellar yields from AGB models (Karakas, 2010)
J/A+A/509/A93 : Carbon-enhanced metal-poor stars (Masseron+, 2010)
J/AJ/142/188 : Metal-poor stars from HES using CH G-band (Placco+, 2011)
J/MNRAS/418/284 : s-process in low-metallicity stars. II. (Bisterzo+, 2011)
J/A+A/548/A34 : Carbon-enhanced metal-poor star abundances (Allen+, 2012)
J/A+A/546/A90 : NLTE analysis of Sr lines (Bergemann+, 2012)
J/ApJ/762/25 : The most metal-poor stars in HES & SDSS. I. (Norris+, 2013)
J/MNRAS/440/1095 : Chemical analysis of CH stars (Karinkuzhi+, 2014)
J/ApJ/781/40 : Metal-poor stars from HES survey. II. Sp. (Placco+, 2014)
J/ApJ/797/21 : Carbon-enhanced metal-poor stars (Placco+, 2014)
J/A+A/579/A28 : Abundances of 3 CEMP stars (Bonifacio+, 2015)
J/MNRAS/446/2348 : Chemical analysis of CH stars. II. (Karinkuzhi+, 2015)
J/MNRAS/459/4299 : Barium stars abundances and kinematics (de Castro+, 2016)
J/A+A/586/A158 : Binary properties of CH and CEMP stars (Jorissen+, 2016)
J/ApJ/833/20 : Carbon-enhanced metal-poor star abundances (Yoon+, 2016)
J/ApJ/835/81 : Bright metal-poor stars from HES Survey. II. (Beers+, 2017)
J/AJ/153/21 : Abund. in the local region. II. (Luck+, 2017)
J/A+A/621/A108 : Rvel compilation for 45 CEMP-no stars (Arentsen+ 2019)
J/A+A/623/A128 : Gal. halo CEMP stars abundances & kinematics (Hansen+, 2019)
J/MNRAS/486/3266 : Chemical analysis of CH stars (Purandardas+, 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)
J/ApJ/907/10 : Samples of VMP HK/HES stars (Limberg+, 2021)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Name Star name
13- 14 I2 h RAh Hour of right ascension (J2000)
16- 17 I2 min RAm Minute of right ascension (J2000)
19- 23 F5.2 s RAs Second of right ascension (J2000)
25 A1 --- DE- Sign of declination (J2000)
26- 27 I2 deg DEd Degree of declination (J2000)
29- 30 I2 arcmin DEm Arcminute of declination (J2000)
32- 36 F5.2 arcsec DEs Arcsecond of declination (J2000)
38- 43 F6.3 mag Bmag [11.8/15.9] B magnitude
45- 50 F6.3 mag Vmag [10.9/14.3] V magnitude
52- 57 F6.3 mag Jmag [8.9/11.9] J-band magnitude
59- 64 F6.3 mag Hmag [8.4/11.3] H-band magnitude
66- 71 F6.3 mag Kmag [8.1/11.1] K band magnitude
73- 77 F5.2 --- SN4200A [8/16] S/N at 4200Å
79- 83 F5.2 --- SN5500A [29/56] S/N at 5500Å
85- 89 F5.2 --- SN7700A [49/90]? S/N at 7700Å
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- Name Main name of the source
13- 16 I4 K Teff [4240/5380]? Effective temperature
18- 21 F4.2 [cm/s2] logg [0.5/3]? Log of surface gravity
23- 26 F4.2 km/s Vt [0.69/3.5]? Microturbulent velocity
28- 32 F5.2 Sun [FeI/H] [-3.5/-0.7] Log of FeI/H abundance
34- 37 F4.2 Sun e_[FeI/H] [0.06/0.2]? [FeI/H] uncertainty
39- 43 F5.2 Sun [FeII/H] [-2.9/-0.7]? Log of FeII/H abundance
45- 48 F4.2 Sun e_[FeII/H] [0.01/0.2]? [FeII/H] uncertainty
50- 56 F7.2 km/s RV [49/180]? Radial velocity
58- 61 F4.2 km/s e_RV [0.02/2.2]? RV uncertainty
63- 69 F7.2 --- RVGaia [52.4/178]? Gaia DR2 radial velocity
71- 74 F4.2 --- e_RVGaia [0.3/1.5]? RVGaia uncertainty
76- 81 F6.2 --- RVrave [72/178]? RAVE DR4 radial velocity
83- 85 F3.1 --- e_RVrave [1.5/2.2]? RVrave uncertainty
87 I1 --- Ref [1/4] Reference (1)
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Note (1): Reference codes as follows:
1 = Our work;
2 = Kennedy et al. 2011AJ....141..102K 2011AJ....141..102K
3 = Frebel et al. (2006, J/ApJ/652/1585)
4 = Beers et al. (2017, J/ApJ/835/81).
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Byte-by-byte Description of file: table9.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.3 0.1nm lambda [4132.9/6430.9] Wavelength, Angstroms
10- 14 A5 --- El Element
16- 20 F5.3 eV Elow [0.087/4.6] Energy, lower level
22- 27 F6.3 [-] loggf [-4.95/-0.02] Log, statistical
weight*oscillator strength
29- 33 F5.1 0.1pm EW-HE0457 [55/145.6]? Equivalent width of line,
HE0457-1805
35- 38 F4.2 [-] Ab-HE0457 [5.3/5.7]? Derived absolute abundance for
line, HE 0457-1805
40- 43 F4.1 0.1pm EW-HE0920 [27.4/92]? Equivalent width of line,
HE0920-0506
45- 48 F4.2 [-] Ab-HE0920 [6.6/6.9]? Derived absolute abundance for
line, HE 0920-0506
50- 55 F6.2 0.1pm EW-HE1241 [20.5/151]? Equivalent width of line,
HE1241-0337
57- 60 F4.2 [-] Ab-HE1241 [4.8/5.3]? Derived absolute abundance for
line, HE 1241-0337
62- 65 F4.1 0.1pm EW-HE1327 [20/83.4]? Equivalent width of line,
HE1327-2116
67- 70 F4.2 [-] Ab-HE1327 [4.5/4.8]? Derived absolute abundance for
line, HE 1327-2116
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Byte-by-byte Description of file: table10.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 F8.3 0.1nm lambda [4161.5/6643.7] Wavelength, Angstroms
10- 14 A5 --- El Element
16- 20 F5.3 eV Elow [0.0/5.8] Energy, lower level
22- 27 F6.3 [-] loggf [-3.5/0.6] Log, statistical
weight*oscillator strength
29- 33 F5.1 0.1pm EW-HE0457 [21.8/150]? Equivalent width of line,
HE0457-1805
35- 38 F4.2 [-] Ab-HE0457 [1.2/7.1]? Derived absolute abundance for
line, HE 0457-1805
40- 44 F5.1 0.1pm EW-HE0920 [12.1/173]? Equivalent width of line,
HE0920-0506
46- 49 F4.2 [-] Ab-HE0920 [1.1/7.6]? Derived absolute abundance for
line, HE 0920-0506
51- 55 F5.1 0.1pm EW-HE1241 [9.2/166]? Equivalent width of line,
HE1241-0337
57- 61 F5.2 [-] Ab-HE1241 [-0.6/6]? Derived absolute abundance for
line, HE 1241-0337
63- 66 F4.1 0.1pm EW-HE1327 [10/98]? Equivalent width of line,
HE1327-2116
68- 72 F5.2 [-] Ab-HE1327 [-0.24/5.5]? Derived absolute abundance for
line, HE 1327-2116
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Byte-by-byte Description of file: table11.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.3 0.1nm lambda [4118.7/7800.3] Wavelength, Angstroms
13- 17 A5 --- El Element
19- 23 F5.3 eV Elow [0/4.1] Energy, lower level
25- 31 F7.4 [-] loggf [-2.3/0.7] Log, statistical
weight*oscillator strength
33- 37 F5.2 [-] Ab-HE0457 [-0.2/4.5]? Derived absolute abundance for
line, HE 0457-1805
39- 43 F5.2 [-] Ab-HE0920 [-0.5/4.5]? Derived absolute abundance for
line, HE 0920-0506
45- 49 F5.2 [-] Ab-HE1241 [-1.6/3.6]? Derived absolute abundance for
line, HE 1241-0337
51- 55 F5.2 [-] Ab-HE1327 [-1.2/3.7]? Derived absolute abundance for
line, HE 1327-2116
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-Jul-2024