J/ApJ/890/119 Iron element abundances in 3 very metal-poor stars (Cowan+, 2020)
Detailed iron-peak element abundances in three very metal-poor stars.
Cowan J.J., Sneden C., Roederer I.U., Lawler J.E., Den Hartog E.A.,
Sobeck J.S., Boesgaard A.M.
<Astrophys. J., 890, 119 (2020)>
=2020ApJ...890..119C 2020ApJ...890..119C
ADC_Keywords: Abundances; Stars, metal-deficient; Spectra, ultraviolet; Optical
Keywords: Atomic physics ; Abundance ratios ; Galaxy chemical evolution ;
Stellar abundances ; Stellar nucleosynthesis
Abstract:
We have obtained new detailed abundances of the Fe-group elements
Sc through Zn (Z=21-30) in three very metal-poor ([Fe/H]~-3) stars:
BD+03 740, BD-13 3442, and CD-33 1173. High-resolution ultraviolet
Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra in
the wavelength range 2300-3050Å were gathered, and complemented by
an assortment of optical echelle spectra. The analysis featured recent
laboratory atomic data for a number of neutral and ionized species for
all Fe-group elements except Cu and Zn. A detailed examination of
scandium, titanium, and vanadium abundances in large-sample
spectroscopic surveys indicates that they are positively correlated in
stars with [Fe/H]≤-2. The abundances of these elements in BD+03 740,
BD-13 3442, CD-33 1173, and HD 84937 (studied in a previous paper of
this series) are in accord with these trends and lie at the high end
of the correlations. Six elements have detectable neutral and ionized
features, and generally their abundances are in reasonable agreement.
For Cr we find only minimal abundance disagreement between the neutral
(mean of [CrI/Fe]=+0.01) and ionized species (mean of [CrII/Fe]=+0.08),
unlike most studies in the past. The prominent exception is Co, for
which the neutral species indicates a significant overabundance (mean
of [CoI/H]=-2.53), while no such enhancement is seen for the ionized
species (mean of [CoII/H]=-2.93). These new stellar abundances,
especially the correlations among Sc, Ti, and V, suggest that models
of element production in early high-mass metal-poor stars should be
revisited.
Description:
The high-resolution spectra for the "program stars" BD+03 740,
BD-13 3442, and CD-33 1173 have been described in detail in Paper I
(Roederer+, 2018, J/ApJ/860/125). Briefly, the spectra in the UV
region (2290-3050Å) were gathered with the Space Telescope Imaging
Spectrograph (STIS) on board the Hubble Space Telescope (HST). The
spectral resolving power was R∼30000. The HST/STIS spectra for the
three program stars were obtained with STIS in Program GO-14232.
Optical spectra of these stars were obtained from online archives from
the ESO Very Large Telescope Ultraviolet and Visual Echelle
Spectrograph (UVES), the Keck I Telescope High Resolution Echelle
Spectrometer (HIRES), and the McDonald Observatory Harlan J. Smith
Telescope and Robert G. Tull Coude Spectrograph. All stars have
optical spectra with R≳40000 and wavelength coverage mostly complete
in the 3050-6800Å range.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 31 4 Model atmospheric parameters from Paper I
(Roederer+, 2018, J/ApJ/860/125)
table2.dat 39 476 Line parameters and abundances
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
B/eso : ESO Science Archive Catalog (ESO, 1991-2021)
J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)
J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)
J/ApJ/667/1267 : CrI transition probabilities (Sobeck+, 2007)
J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)
J/A+A/493/601 : Lithium abundances of halo dwarfs (Hosford+, 2009)
J/ApJS/182/51 : Transitions of rare earth elements (Lawler+, 2009)
J/ApJS/182/80 : Rare earth abundances (Sneden+, 2009)
J/ApJ/724/341 : Nucleosynthesis of massive metal-free stars (Heger+, 2010)
J/ApJ/743/140 : Abundances (Be,α) in metal-poor stars (Boesgaard+, 2011)
J/ApJS/194/35 : Atomic transition probabilities of Mn (Den Hartog+, 2011)
J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)
J/ApJ/764/21 : Stellar evolutionary models with 13-120Msun (Chieffi+, 2013)
J/ApJS/208/27 : Sun and HD 84937 TiII log(gf) and abundances (Wood+, 2013)
J/ApJ/762/26 : Most metal-poor stars. II. Galactic halo stars (Yong+, 2013)
J/ApJS/215/20 : Vanadium log(gf) and transition probabilities (Lawler+, 2014)
J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)
J/ApJS/214/18 : VII log(gf) values, and V abundance in HD 84937 (Wood+ 2014)
J/ApJS/211/20 : NiI transition probability measurements (Wood+, 2014)
J/ApJS/220/13 : Co I transition probabilities (Lawler+, 2015)
J/ApJS/225/24 : NuGrid stellar data set I. Yields (H to Bi) (Pignatari+, 2016)
J/ApJ/817/53 : Fe-group abundance analysis in HD84937 (Sneden+, 2016)
J/ApJS/228/10 : Transitions for 183 lines of Cr II (Lawler+, 2017)
J/ApJ/857/2 : Abundances in 6 metal-poor stars (Roederer+, 2018)
J/ApJ/860/125 : Six warm metal-poor stars iron abundances (Roederer+, 2018)
J/ApJS/234/25 : Vanadium transitions in the spectrum of Arcturus (Wood+, 2018)
J/ApJS/237/8 : Line lists for X1Σ+ AlF and AlCl (Yousefi+, 2018)
J/ApJ/870/2 : PUSH CCSN to explosions in spherical symmetry. III.
(Curtis+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Star name
12- 15 I4 K Teff [6300/6625] Effective temperature
17- 20 F4.2 [cm/s2] logg [3.97/4.29] Log of surface gravity
22- 25 F4.2 km/s Vt [1.5/1.7] Microturbulent velocity
27- 31 F5.2 [Sun] [M/H] [-3/-2.15] Metallicity
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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- 7 F7.2 0.1nm lambda [2286.16/5409.77] Line Wavelength
9- 12 A4 --- Ion Line Identification
14- 18 F5.3 eV chi [0/4.08] Lower State Excitation Energy
20- 24 F5.2 --- log(gf) [-3.07/1.55] Transition Probability
26- 29 F4.2 --- log(eps)1 [0.4/5.02]? Abundance for BD+03 740
31- 34 F4.2 --- log(eps)2 [0.6/5]? Abundance for BD-13 3442
36- 39 F4.2 --- log(eps)3 [0.4/4.8]? Abundance for CD-33 1173
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History:
From electronic version of the journal
References:
Roederer et al. Paper I. 2018ApJ...860..125R 2018ApJ...860..125R Cat. J/ApJ/860/125
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Jul-2021