J/AJ/147/136 Stars of very low metal abundance. VI. Abundances (Roederer+, 2014)
A search for stars of very low metal abundance.
VI. Detailed abundances of 313 metal-poor stars.
Roederer I.U., Preston G.W., Thompson I.B., Shectman S.A., Sneden C.,
Burley G.S., Kelson D.D.
<Astron. J., 147, 136 (2014)>
=2014AJ....147..136R 2014AJ....147..136R
ADC_Keywords: Stars, population II ; Stars, metal-deficient ; Abundances ;
Radial velocities ; Equivalent widths ; Effective temperatures
Keywords: Galaxy: halo - nuclear reactions, nucleosynthesis, abundances -
stars: abundances - stars: atmospheres - stars: Population II
Abstract:
We present radial velocities, equivalent widths, model atmosphere
parameters, and abundances or upper limits for 53 species of 48
elements derived from high resolution optical spectroscopy of 313
metal-poor stars. A majority of these stars were selected from the
metal-poor candidates of the HK Survey of Beers, Preston, and
Shectman. We derive detailed abundances for 61% of these stars for the
first time. Spectra were obtained during a 10yr observing campaign
using the Magellan Inamori Kyocera Echelle spectrograph on the
Magellan Telescopes at Las Campanas Observatory, the Robert G. Tull
Coude Spectrograph on the Harlan J. Smith Telescope at McDonald
Observatory, and the High Resolution Spectrograph on the Hobby-Eberly
Telescope at McDonald Observatory. We perform a standard LTE abundance
analysis using MARCS model atmospheres, and we apply line-by-line
statistical corrections to minimize systematic abundance differences
arising when different sets of lines are available for analysis. We
identify several abundance correlations with effective temperature. A
comparison with previous abundance analyses reveals significant
differences in stellar parameters, which we investigate in detail. Our
metallicities are, on average, lower by ~0.25dex for red giants
and ~0.04dex for subgiants. Our sample contains 19 stars with
[Fe/H]≤-3.5, 84 stars with [Fe/H]≤-3.0, and 210 stars with
[Fe/H]≤-2.5. Detailed abundances are presented here or elsewhere for
91% of the 209 stars with [Fe/H]≤-2.5 as estimated from medium
resolution spectroscopy by Beers, Preston, and Shectman. We will
discuss the interpretation of these abundances in subsequent papers.
Description:
Observations conducted at Las Campanas Observatory were made with the
Magellan Inamori Kyocera Echelle (MIKE) spectrograph. This instrument
is currently mounted on the f/11 Nasmyth platform at the 6.5m Landon
Clay Telescope (Magellan II). Early observations for our program were
taken while MIKE was mounted on the 6.5m Walter Baade Telescope
(Magellan I) in 2003. The MIKE spectra were taken with the 0.7''*5.0''
slit, yielding a resolving power of R∼41000 in the blue and R∼35000 in
the red.
Other observations were made with the Robert G. Tull Coude
Spectrograph on the 2.7m Harlan J. Smith Telescope at McDonald
Observatory. These spectra were taken with the 2.4''*8.0'' slit,
yielding a resolving power R∼33000.
Additional observations were made with the High Resolution
Spectrograph (HRS) on the 9.2m Hobby-Eberly Telescope (HET) at
McDonald Observatory. Using the 1.0'' slit yields a resolving power
R∼30000.
We have observed 250 stars with Magellan+MIKE, 52 stars with
Smith+Tull, and 19 stars with HET+HRS. After accounting for duplicate
observations of the same star and three double-lined spectroscopic
binaries whose abundances are not examined in this paper, we are left
with a total of 313 stars. These 532 individual observations account
for nearly 495hr of integration time. In Table2 we present a record of
all observations.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 78 532 Log of observations
table3.dat 57 312 Observational stellar data
table5.dat 45 148362 Sample table of equivalent width (EW) measurements
table7.dat 78 313 Magnitudes, reddenings, colors, atmospheric
parameters, and random uncertainties
table8.dat 27 479 Atomic data
table11.dat 39 67457 Abundances derived from individual lines
table12.dat 57 16589 Mean abundances
table15.dat 72 313 Non-Local Thermodynamic Equilibrium (non-LTE)
abundance corrections
table16.dat 57 229 Line abundance corrections and uncertainties
refs.dat 236 90 References
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See also:
B/sb9 : 9th Catalogue of Spectroscopic Binary Orbits (Pourbaix+ 2004-2014)
V/130 : Geneva-Copenhagen Survey of Solar neighbourhood III (Holmberg+, 2009)
J/ApJ/762/26 : Most metal-poor stars. II. 190 Galactic halo stars
(Yong+, 2013)
J/ApJ/762/25 : The most metal-poor stars in HES and SDSS. I. (Norris+, 2013)
J/AJ/145/13 : Metal-poor stars from SDSS/SEGUE. I. Abundances (Aoki+, 2013)
J/ApJ/742/54 : CASH project II. 14 extremely metal-poor stars (Hollek+, 2011)
J/A+A/509/A93 : Carbon-enhanced metal-poor stars (Masseron+, 2010)
J/A+A/522/A26 : Fe Abundances in metal-poor stars (Sbordone+ 2010)
J/A+A/501/519 : Extremely metal-poor turnoff stars abundances
(Bonifacio+, 2009)
J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)
J/A+A/484/721 : HES survey. IV. Candidate metal-poor stars (Christlieb+, 2008)
J/AJ/135/196 : Radial velocities of 45 metal-poor field stars (Carney+, 2008)
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/ApJS/168/128 : UBVRcIc photometry of FHB and metal-poor stars (Beers+, 2007)
J/AJ/132/85 : Equivalent width of 33 metal-poor RHB (Preston+, 2006)
J/AJ/132/137 : Abundances of extremely metal-poor carbon stars (Cohen+, 2006)
J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)
J/AJ/130/2804 : Carbon abundances in metal-poor stars (Rossi+, 2005)
J/AJ/128/2402 : Extremely metal-poor star candidates abundances (Lai+, 2004)
J/A+A/422/527 : Metal-poor star uvby-beta photometry. X. (Schuster+, 2004)
J/AJ/119/2866 : Proper motions of metal-poor stars (Beers+, 2000)
J/ApJS/123/639 : UBV photometry of metal-weak candidates (Norris+, 1999)
J/A+A/314/191 : Atmospheric parameters in metal-poor stars. I (Gratton+, 1996)
J/ApJS/96/175 : Kinematics of Metal-Poor Stars. I. (Beers+ 1995)
J/AJ/108/538 : Metal-poor MS stars UBV photometry (Preston+ 1994)
J/A+A/290/885 : Abundances of very metal-poor stars (Primas+, 1994)
J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)
J/AJ/90/2089 : Stars of very low metal abundance. I (Beers+, 1985)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star identifier
14- 32 A19 --- Tel The Telescope/Instrument used (1)
34- 36 A3 --- Obs Observer code (2)
38- 42 I5 s Exp Exposure time
44- 53 A10 "Y:M:D" Obs.date Date of the observation
55- 59 A5 "h:m" Obs.time UT time of mid exposure
61- 71 F11.3 d HJD Heliocentric Julian Date
73- 78 F6.1 km/s HRV ? Heliocentric radial velocity
--------------------------------------------------------------------------------
Note (1): Instruments used:
Magellan-Baade/MIKE = 6.5m Walter Baade Telescope (Magellan I)/Magellan Inamori
Kyocera Echelle (MIKE) spectrograph;
Magellan-Clay/MIKE = 6.5m Landon Clay Telescope (Magellan II)/Magellan Inamori
Kyocera Echelle (MIKE) spectrograph;
McDonald-HET/HRS = High Resolution Spectrograph (HRS) on the 9.2m
Hobby-Eberly Telescope (HET) at McDonald Observatory;
McDonald-Smith/Tull = Robert G. Tull Coude Spectrograph on the 2.7m Harlan
J. Smith Telescope at McDonald Observatory.
Note (2): Observer codes are defined as follows:
GWP = George W. Preston;
IBT = Ian B. Thompson;
IUR = Ian U. Roederer;
SAS = Stephen A. Shectman.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star identifier
14- 19 F6.1 km/s ? Mean radial velocity
21 I1 --- B [0/3] Binarity flag: suspect if B≥2 (1)
23- 33 A11 --- r_ Reference for ; in refs.dat file
35- 39 I5 s Exp Total exposure time
41 I1 --- No Number of observations
43- 45 I3 --- SN3950 Signal-to-noise at 3950Å
47- 49 I3 --- SN4550 Signal-to-noise at 4550Å
51- 53 I3 --- SN5200 Signal-to-noise at 5200Å
55- 57 I3 --- SN6750 Signal-to-noise at 6750Å
--------------------------------------------------------------------------------
Note (1): Binary flags are defined as follows:
0 = The star has only been observed during a single epoch;
1 = No radial velocity variations detected in multiple epochs;
2 = Radial velocity variations detected, suspected binary,
no systemic velocity listed;
3 = Spectroscopic binary confirmed by other studies, systemic velocity listed.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star identifier
14- 20 F7.2 0.1nm lambda Wavelength λ; in Å
22- 26 A5 --- Ion Species identifier
28- 31 F4.2 eV EP Excitation Potential
33- 37 F5.2 [-] loggf Log of the oscillator strength
39- 43 F5.1 10-13m EW ? Equivalent width; in mÅ
45 A1 --- f_EW [ls] Derived abundance (1)
--------------------------------------------------------------------------------
Note (1): Flag on EW as follows:
s = Abundance was derived from spectrum synthesis;
l = An upper limit on the abundance was derived from the line.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Cl Star class (1)
4- 15 A12 --- Name Star identifier
17 A1 --- f_Name [c] Star with reliable parallax and E(B-V)<0.12
19- 23 F5.2 mag Vmag V-band magnitude
25- 29 F5.3 mag E(B-V) Reddening
31- 34 F4.2 mag (B-V)0 ? Dereddened (B-V) color index
36- 39 F4.2 mag (V-K)0 ? Dereddened (V-K) color index
41- 44 I4 K Teff Effective temperature
46- 49 F4.2 [cm/s2] logg Log of surface gravity
51- 54 F4.2 km/s Vt Microturbulent velocity
56- 60 F5.2 [-] [M/H] Metallicity
62- 63 I2 K e_Teff 1σ uncertainty in Teff
65- 68 F4.2 [cm/s2] e_logg 1σ uncertainty in logg
70- 73 F4.2 km/s e_Vt 1σ uncertainty in Vt
75- 78 F4.2 [-] e_[M/H] 1σ uncertainty in [M/H] (2)
--------------------------------------------------------------------------------
Note (1): Classification scheme is defined as follows:
BS = Blue Straggler-like stars warmer than the main sequence turnoff;
HB = stars on the Horizontal Branch;
MS = stars on the Main Sequence;
RG = stars on the Red Giant branch;
SG = stars on the SubGiant branch.
Note (2): e[M/H]=eFeI.
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Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 0.1nm lambda Wavelength λ; in Å
9- 13 A5 --- Ion Species identifier
15- 18 F4.2 eV EP Excitation Potential
20- 24 F5.2 [-] loggf Log of the oscillator strength
26- 27 I2 --- Ref Reference; in refs.dat file (1)
--------------------------------------------------------------------------------
Note (1): The reference for the CH A2Δ-X2Π G band is B. Plez
(2007, private communication) while the reference for the
NH A3Π-X3Σ and CN B2Σ-X2Σ bands is Kurucz &
Bell (1995KurCD..23.....K 1995KurCD..23.....K).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table11.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star identifier
14- 18 A5 --- Ion Species identifier
20- 26 F7.2 0.1nm lambda Wavelength λ; in Å
28 A1 --- l_log(e) Limit flag on log(e)
30- 34 F5.2 [-] log(e) Log abundance (logε)
36- 39 F4.2 [-] e_log(e) ? The 1σ error in log(e)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table12.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star identifier
14- 19 A6 --- Ion Species identifier
21- 23 I3 --- Nl Number of lines used
25 A1 --- l_log(e) Limit flag on log(e)
27- 31 F5.2 [-] log(e) ? Log mean abundance (logε)
33- 37 F5.2 [-] [X/Fe] ? Abundance relative to FeI and FeII
39- 42 F4.2 [-] s_[X/Fe] ? Statistical uncertainty in [X/Fe]
44- 47 F4.2 [-] e_[X/Fe] ? Total uncertainty in [X/Fe]
49- 52 F4.2 [-] e2_[X/Fe] ? Neutrals uncertainty in [X/Fe]
54- 57 F4.2 [-] e3_[X/Fe] ? Ions uncertainty in [X/Fe]
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table15.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star identifier
14- 18 F5.2 --- LiI-6707 ? LiI (6707Å) non-LTE abundance correction
20- 24 F5.2 --- OI-7771 ? OI (7771Å) non-LTE abundance correction
26- 30 F5.2 --- OI-7774 ? OI (7774Å) non-LTE abundance correction
32- 36 F5.2 --- OI-7775 ? OI (7775Å) non-LTE abundance correction
38- 42 F5.2 --- NaI-5682 ? NaI (5682Å) non-LTE abundance correction
44- 48 F5.2 --- NaI-5688 ? NaI (5688Å) non-LTE abundance correction
50- 54 F5.2 --- NaI-5889 ? NaI (5889Å) non-LTE abundance correction
56- 60 F5.2 --- NaI-5895 ? NaI (5895Å) non-LTE abundance correction
62- 66 F5.2 --- KI-7664 ? KI (7664Å) non-LTE abundance correction
68- 72 F5.2 --- KI-7698 ? KI (7698Å) non-LTE abundance correction
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table16.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Ion Species identifier
7- 13 F7.2 0.1nm lambda Wavelength λ; in Å
15- 19 F5.2 [-] RGcor ? Abundance correction for stars on the Red
Giant branch
21- 24 F4.2 [-] e_RGcor ? Uncertainty in RGcor
26- 30 F5.2 [-] SGcor ? Abundance correction for stars on the Subgiant
branch
32- 35 F4.2 [-] e_SGcor ? Uncertainty in SGcor
37- 41 F5.2 [-] HBcor ? Abundance correction for stars on the
Horizontal Branch
43- 46 F4.2 [-] e_HBcor ? Uncertainty in HBcor
48- 52 F5.2 [-] MScor ? Abundance correction for stars on the Main
Sequence branch
54- 57 F4.2 [-] e_MScor ? Uncertainty in MScor
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode Bibliographic code
24- 41 A18 --- Aut Author's name
43-236 A194 --- Com Comments
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Beers et al., Paper I, 1985AJ.....90.2089B 1985AJ.....90.2089B, Cat. J/AJ/90/2089
Beers et al., Paper II, 1992AJ....103.1987B 1992AJ....103.1987B, Cat. J/AJ/103/1987
Norris et al., Paper III, 1999ApJS..123..639N 1999ApJS..123..639N, Cat. J/ApJS/123/639
Anthony-Twarog et al., Paper IV, 2000AJ....119.2882A 2000AJ....119.2882A
Bonifacio et al., Paper V, 2000AJ....120.2065B 2000AJ....120.2065B
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 25-Sep-2014