J/ApJ/913/11 Sp. follow-up of bright metal-poor stars (Limberg+, 2021)
Targeting bright metal-poor stars in the disk and halo systems of the Galaxy.
Limberg G., Santucci R.M., Rossi S., Shank D., Placco V.M., Beers T.C.,
Schlaufman K.C., Casey A.R., Perottoni H.D., Lee Y.S.
<Astrophys. J., 913, 11-11 (2021)>
=2021ApJ...913...11L 2021ApJ...913...11L (SIMBAD/NED BibCode)
ADC_Keywords: Stars, metal-deficient; Spectra, optical; Abundances;
Photometry, infrared; Proper motions; Stars, distances
Keywords: Population II stars; Milky Way stellar halo; Milky Way disk
CEMP stars; Spectroscopy; Chemical abundances; Stellar atmospheres
Milky Way dynamics; Milky Way evolution; Milky Way formation
Abstract:
We present the results of spectroscopic follow-up for
1897 low-metallicity star candidates, selected from the Best and
Brightest (B&B) Survey, carried out with the GMOS-N/S (Gemini
North/South telescopes) and Goodman (SOAR Telescope) spectrographs.
From these low-resolution (R∼2000) spectra, we estimate stellar
atmospheric parameters, as well as carbon and magnesium abundance
ratios. We confirm that 56% of our program stars are metal-poor
([Fe/H]←1.0), 30% are very metal-poor (VMP; [Fe/H]←2.0), and 2%
are extremely metal-poor (EMP; [Fe/H]←3.0). There are
191 carbon-enhanced metal-poor (CEMP) stars, resulting in CEMP
fractions of 19% and 43% for the VMP and EMP regimes, respectively. A
total of 94 confirmed CEMP stars belong to Group I (A(C)≳7.25) and
97 to Group II (A(C)≲7.25) in the Yoon-Beers A(C)-[Fe/H] diagram.
Moreover, we combine these data with Gaia EDR3 astrometric information
to delineate new target-selection criteria, which have been applied to
the Goodman/SOAR candidates, to more than double the efficiency for
identification of bona fide VMP and EMP stars in comparison to random
draws from the B&B catalog. We demonstrate that this target-selection
approach can achieve success rates of 96%, 76%, 28%, and 4% for
[Fe/H]≤-1.5, ≤-2.0, ≤-2.5 and ≤-3.0, respectively. Finally, we
investigate the presence of dynamically interesting stars in our
sample. We find that several VMP/EMP ([Fe/H]≤-2.5) stars can be
associated with either the disk system or halo substructures like
Gaia-Sausage/Enceladus and Sequoia.
Description:
All of our targets have been selected as metal-poor candidates by
Schlaufman & Casey (2014, J/ApJ/797/13) as part of the Best &
Brightest (B&B) Survey.
A total of 1897 stars have been observed with either the Gemini
Multi-Object Spectrographs (GMOS-N/S) or Goodman spectrograph at the
Gemini (North/South; 8.1m) and the Southern Astrophysical Research
(SOAR; 4.1m) telescopes, respectively.
The Gemini North and South observations were obtained between 2014A
and 2019B with R∼2000-2800 and a wavelength coverage of 3200-5800Å.
The typical wavelength coverage for Goodman/SOAR spectra is
3600-6200Å, and the achieved resolution is R∼1300.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 108 1897 Coordinates and observing details
table2.dat 82 1897 Colors, magnitudes and reddening estimates
table3.dat 76 1897 Stellar atmospheric parameters and abundances
table4.dat 84 1897 Phase-space information from Gaia EDR3
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See also:
III/46 : Ap and Am Stars (Bertaud+ 1974; Bidelman+ 1973)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/336 : AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)
III/279 : RAVE 5th data release (Kunder+, 2017)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
J/AJ/90/2089 : Stars of very low metal abundance. I (Beers+, 1985)
J/AJ/100/1191 : Giants DDO photometry (Morrison+, 1990)
J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)
J/ApJS/96/175 : Kinematics of Metal-Poor Stars. I. (Beers+ 1995)
J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)
J/AJ/128/1177 : Galactic stellar abundances (Venn+, 2004)
J/AJ/130/2804 : Carbon abundances in metal-poor stars (Rossi+, 2005)
J/ApJ/652/1585 : Bright metal-poor stars from HES survey (Frebel+, 2006)
J/ApJ/655/492 : Equivalent widths of 26 metal-poor stars (Aoki+, 2007)
J/AJ/135/564 : Photometry and spectroscopy of BHB candidates (Brown+, 2008)
J/A+A/484/721 : HES survey. IV. Candidate metal-poor stars (Christlieb+, 2008)
J/AJ/136/2050 : SEGUE stellar parameter pipeline. II. (Lee+, 2008)
J/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)
J/ApJ/724/341 : Nucleosynthesis of massive metal-free stars (Heger+, 2010)
J/AJ/141/90 : SEGUE stellar parameter pipeline. V. (Lee+, 2011)
J/MNRAS/418/284 : s-process in low-metallicity stars. II. (Bisterzo+, 2011)
J/A+A/548/A34 : Abundances of carbon-enhanced metal-poor stars (Allen+, 2012)
J/ApJ/762/26 : Most metal-poor stars. II. Galactic halo stars (Yong+, 2013)
J/ApJ/762/27 : Most metal-poor stars. III. [Fe/H]≤-3.0 stars (Yong+, 2013)
J/ApJ/773/33 : The metal-poor subgiant BD+44 493 (Ito+, 2013)
J/ApJ/781/40 : Metal-poor stars from HES survey. II. Sp. (Placco+, 2014)
J/A+A/562/A71 : Abundances of solar neighbourhood dwarfs (Bensby+, 2014)
J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)
J/ApJ/788/180 : Very metal-poor stars in the Milky Way's halo (Carollo+, 2014)
J/ApJ/794/58 : Metal-poor stars in the Galaxy thick disk (Beers+, 2014)
J/ApJ/797/13 : Abundances of bright metal-poor stars (Schlaufman+, 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/ApJ/824/L19 : Carbon-enhanced metal-poor star BD+44493 EWs (Roederer+, 2016)
J/ApJ/833/20 : Carbon-enhanced metal-poor (CEMP) star abund. (Yoon+, 2016)
J/ApJ/833/119 : Distances of Gaia DR1 TGAS sources (Astraatmadja+, 2016)
J/ApJ/833/225 : -2.6≤[Fe/H]≤0.2 F and G dwarfs. II. Abundances (Zhao+, 2016)
J/ApJ/835/81 : Bright metal-poor stars from HES Survey. II. (Beers+, 2017)
J/A+A/608/A46 : Constraining cosmic scatter (Reggiani+, 2017)
J/MNRAS/472/2963 : Metallicities of Pristine stars (Youakim+, 2017)
J/ApJ/858/92 : RPA Southern Pilot Search of 107 Stars (Hansen+, 2018)
J/AJ/155/256 : Sp. validation of RAVE metal-poor stars (Placco+, 2018)
J/ApJS/238/16 : LAMOST-DR3 very metal-poor star catalog (Li+, 2018)
J/ApJ/870/122 : Sp. of low-metallicity star candidates (Placco+, 2019)
J/ApJ/882/40 : Lanthanide fraction in metal-poor stars (Ji+, 2019)
J/ApJ/891/39 : LAMOST DR3 VMP stars of the Gal. halo (Yuan+, 2020)
J/ApJ/894/34 : Metallicity from SDSS & SMSS in halo stars (Dietz+, 2020)
J/ApJ/898/150 : High-res. MIKE obs. of metal-poor stars (Ezzeddine+, 2020)
J/ApJS/249/30 : R-Process Alliance: metal-poor star sp. (Holmbeck+, 2020)
J/AJ/160/173 : Metal-poor star abundances in Inner Bulge (Reggiani+, 2020)
J/ApJ/905/20 : Metal-poor stars observed with SALT/HRS (Rasmussen+, 2020)
J/ApJ/907/10 : The very metal-poor HK/HES stars (Limberg+, 2021)
J/ApJ/908/79 : The r-process Alliance; abundances in 519 stars (Gudin+, 2021)
J/A+A/649/A3 : Gaia EDR3 photometric passbands (Riello+, 2021)
J/ApJ/926/26 : DTGs of metal-poor stars. I. (Shank+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs; J2000)
18- 36 I19 --- Gaia ? Gaia EDR3 identifier
38- 45 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
47- 54 F8.4 deg DEdeg Declination in decimal degrees (J2000)
56- 63 F8.4 deg GLON Galactic longitude
65- 72 F8.4 deg GLAT Galactic latitude
74- 85 A12 --- Tel Telescope identifier (1)
87- 93 A7 --- Inst Instrument identifier
95-108 A14 --- PID Program identifier
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Note (1): Telescope as follows:
Gemini North = the Gemini-North 8.1m telescope (865 occurrences)
Gemini South = the Gemini-South 8.1m telescope (922 occurrences)
SOAR = the Southern Astrophysical Research (SOAR) 4.1m telescope
(110 occurrences)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs; J2000)
18- 36 I19 --- Gaia ? Gaia EDR3 identifier
38- 43 F6.3 mag Vmag [9.5/15] Apparent V band magnitude (2)
45- 50 F6.3 mag B-V [-1.2/1.6] The (B-V) color index (2)
52- 57 F6.3 mag Gmag [9.4/16.5]? Apparent Gaia EDR3 G band magnitude
59- 63 F5.3 mag BP-RP [0/2.5]? Gaia (blue-red) passband color index
65- 70 F6.3 mag Jmag [8.7/15] Apparent 2MASS J band magnitude
72- 76 F5.3 mag J-K [0.18/0.9] 2MASS (J-K) color index
78- 82 F5.3 mag E(B-V) [0.003/0.3] The (B-V) color excess
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Note (2): From the AAVSO Photometric All Sky Survey (APASS) DR9 (II/336).
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs; J2000)
18- 36 I19 --- Gaia ? Gaia EDR3 identifier
38- 41 I4 K Teff [4054/8401]? Effective temperature
43- 46 F4.2 [cm/s2] logg [0.48/5]? log surface gravity
48- 52 F5.2 [Sun] [Fe/H] [-4/0.23]? Metallicity
54- 58 F5.2 [Sun] [C/Fe] [-1.8/3.3]? log C/Fe elemental abundance
60- 64 F5.2 [Sun] [C/Fe]c [-1.8/3.3]? log corrected C/Fe abundance (3)
66- 70 F5.2 --- ACc [0/10.4]? Absolute carbon abundance (3)
72- 76 F5.2 [Sun] [Mg/Fe] [-0.2/0.6]? log Mg/Fe elemental abundance
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Note (3): Corrected for evolutionary status (Placco+, 2014, J/ApJ/797/21).
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs; J2000)
18- 36 I19 --- Gaia ? Gaia EDR3 identifier
38- 43 F6.1 km/s Vlsr [-535/469]? Local Standard of Rest velocity
45- 49 F5.2 kpc Dist [0.05/17.4]? Heliocentric distance
51- 54 F4.2 kpc e_Dist [0/5.2]? Uncertainty in Dist
56- 63 F8.3 mas/yr pmRA [-189/240]? Gaia EDR3 proper motion along RA
65- 72 F8.3 mas/yr pmDE [-264/246]? Gaia EDR3 proper motion along DE
74- 78 F5.2 kpc ZGal [-9.5/17.3]? Galactic scale height
80- 84 F5.1 km/s VTav [0/675]? Total available velocity
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 07-Oct-2022