J/PASP/121/117 Fe and Ti abundances of 12 low-metallicity M stars (Woolf+, 2009)
Calibrating M-dwarf metallicities using molecular indices: extension to
low-metallicity stars.
Woolf V.M., Lepine S., Wallerstein G.
<Publ. Astron. Soc. Pac., 121, 117-124 (2009)>
=2009PASP..121..117W 2009PASP..121..117W
ADC_Keywords: Stars, dwarfs ; Stars, M-type ; Abundances
Abstract:
We have calculated Fe and Ti abundances in 12 low-metallicity main
sequence M stars using high-resolution spectra. These subdwarf and
extreme-subdwarf stars allow us to extend our calibration of a method
to determine cool-dwarf-star metallicities using molecular band
strength indices from low-resolution spectra. Our calibration can now
be used to determine metallicity to within ±0.3dex for stars with
[Fe/H] between -1.5 and +0.05 and temperatures between 3500 and 4000K.
We also report a method to estimate temperatures for M dwarfs using
equivalent width measurements of the infrared CaII triplet and the
KI line at 7699Å. Our metallicity measurements show that the recently
proposed classification system for low-mass stars (dwarfs, subdwarfs,
extreme subdwarfs, and ultrasubdwarfs) does represent a metallicity
sequence, with the ultrasubdwarfs the most metal-poor stars.
Description:
We obtained spectra of 12 subdwarf and extreme-subdwarf M stars using
queue scheduled observing of the Hobby-Eberly Telescope. The spectra
were measured using the high-resolution spectrograph set to give
spectral resolution λ/Δλ∼30,000.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 92 12 M and K dwarf magnitudes and parallaxes
table3.dat 49 274 Fe and Ti line data
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Star name
17- 20 A4 --- --- [LSPM]
22- 31 A10 --- LSPM LSPM designation (JHHMM+DDMM, Cat. I/298)
33- 39 A7 --- SpType Spectral type (4)
41- 46 F6.3 mag Vmag ? V magnitude (1)
48- 52 F5.3 mag e_Vmag ? rms uncertainty on Vmag
54- 59 F6.3 mag Ksmag Ks magnitude (2)
61- 65 F5.3 mag e_Ksmag rms uncertainty on Ksmag
67- 72 F6.3 mag Hmag ? H magnitude (2)
74- 78 F5.3 mag e_Hmag ? rms uncertainty on Hmag
80- 83 F4.1 mas plx ? Parallax
85- 88 F4.2 mas e_plx ? rms uncertainty on plx
90- 92 A3 --- r_plx Reference for plx (3)
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Note (1): V photometry from Mermilliod, Mermilliod & Hauck,
1997A&AS..124..349M 1997A&AS..124..349M except LHS 318 from Smart et al. 2007A&A...464..787S 2007A&A...464..787S
Note (2): Ks and H photometry from Cutri et al. (2003, Cat. II/246).
Note (3): References as follows:
RG = Reid & Gizis (2005, Cat. III/198)
Tor = Smart et al. (2007A&A...464..787S 2007A&A...464..787S)
Yal = van Altena et al. (1995, Cat. I/238)
Note (4): The spectral type is categorized with 'sd' = subdwarf,
'esd' = extreme subdwarfs and 'usd' = ultra subdwarfs, in order
of decreasing apparent metal content.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Star name
17- 20 A4 --- El Element
22- 28 F7.2 0.1nm lambda Wavelength
30- 33 F4.2 eV chi Excitation potential
35- 40 F6.3 [-] loggf Oscillator strength
42- 44 I3 0.1pm EW Equivalent width
46- 49 F4.2 [-] logN Abundance
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 26-Apr-2009