J/ApJ/601/485 Synthetic Lick indices of alpha-enhanced stars (Franchini+, 2004)
Synthetic Lick indices and detection of α-enhanced stars.
Franchini M., Morossi C., Di Marcantonio P., Malagnini M.L., Chavez M.,
Rodriguez-Merino L.
<Astrophys. J., 601, 485-499 (2004)>
=2004ApJ...601..485F 2004ApJ...601..485F
ADC_Keywords: Stars, late-type ; Abundances
Keywords: Galaxy: stellar content - stars: abundances - stars: late-type
Abstract:
Synthetic Lick indices computed with solar scaled abundances and
with α-element enhancement are presented and compared with
predictions from both theoretical computations (Tripicco & Bell
(1995AJ....110.3035T 1995AJ....110.3035T); Thomas, Maraston, & Bender
(2003MNRAS.339..897T 2003MNRAS.339..897T); Barbuy et al., 2003, Cat. J/A+A/404/661) and
empirical fitting functions (de Freitas Pacheco, 1996MNRAS.278..841D 1996MNRAS.278..841D).
We propose selected combinations of indices capable of singling out
α-enhanced stars without requiring previous knowledge of their
main atmospheric parameters. By applying this approach to the 460
stars in the Worthey et al. (1994, Cat. J/ApJS/94/687) catalog, we
detected a list of 82 candidate α-enhanced stars. The
confirmation of α-enhancement was obtained by searching the
literature for individual element abundance determinations from
high-resolution spectroscopy for a subsample of 34 stars. Preliminary
discussion of the properties of the detected α-enhanced stars
with respect to their [Fe/H] values and kinematics is presented.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1a.dat 69 56 The α enhanced candidate stars from the
four panels of Figure 8 (Ca4227)
table1b.dat 69 47 The α enhanced candidate stars from the
four panels of Figure 8 (Mg2)
table1c.dat 69 17 The α enhanced candidate stars from the
four panels of Figure 8 (Mgb)
table1d.dat 69 59 The α enhanced candidate stars from the
four panels of Figure 8 (CaMg)
table2.dat 62 34 α-Enhanced Candidate Stars Discussed
in the Text
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See also:
J/ApJS/94/687 : Old stellar populations. V. (Worthey+, 1994)
Byte-by-byte Description of file: table1a.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- HD ? HD number
7- 9 A3 --- m_HD Multiplicity index on HD
11- 24 A14 --- OID1 First other identifier
26- 42 A17 --- OID2 Second other identifier
44- 48 F5.3 0.1nm Ca4227 The Lick Ca4227 index in Angstroms
50- 55 F6.3 0.1nm NaD The Lick NaD index in Angstroms
57- 62 F6.3 --- da Dimensionless distance (G1)
64- 69 F6.3 [Sun] [Fe/H] ? Log of the iron to hydrogen abundance
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Byte-by-byte Description of file: table1b.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- HD ? HD number
7- 9 A3 --- m_HD Multiplicity index on HD
11- 24 A14 --- OID1 First other identifier
26- 42 A17 --- OID2 Second other identifier
44- 48 F5.3 0.1nm Mg2 The Lick Mg2 index in Angstroms
50- 55 F6.3 0.1nm NaD The Lick NaD index in Angstroms
57- 62 F6.3 --- db Dimensionless distance (G1)
64- 69 F6.3 [Sun] [Fe/H] ? Log of the iron to hydrogen abundance
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Byte-by-byte Description of file: table1c.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- HD ? HD number
7- 9 A3 --- m_HD Multiplicity index on HD
11- 24 A14 --- OID1 First other identifier
26- 42 A17 --- OID2 Second other identifier
44- 48 F5.3 0.1nm Mgb The Lick Mgb index in Angstroms
50- 55 F6.3 0.1nm NaD The Lick NaD index in Angstroms
57- 62 F6.3 --- dc Dimensionless distance (G1)
64- 69 F6.3 [Sun] [Fe/H] ? Log of the iron to hydrogen abundance
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Byte-by-byte Description of file: table1d.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- HD ? HD number
7- 9 A3 --- m_HD Multiplicity index on HD
11- 24 A14 --- OID1 First other identifier
26- 42 A17 --- OID2 Second other identifier
44- 48 F5.3 0.1nm CaMg The Lick CaMg index in Angstroms
50- 55 F6.3 0.1nm NaD The Lick NaD index in Angstroms
57- 62 F6.3 --- dd Dimensionless distance (G1)
64- 69 F6.3 [Sun] [Fe/H] ? Log of the iron to hydrogen abundance
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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- 6 I6 --- HD HD number
7 A1 --- m_HD Multiplicity index on HD
9- 14 F6.3 --- [Fe/H] Metallicity
16- 19 F4.2 0.1nm NaD NaD index
21- 24 F4.2 0.1nm Ca4227 ? Ca4227 index
26- 29 F4.2 --- da ? Distance of the corresponding point from the
boundary line of NaD-Ca4227 diagram (1)
31- 35 F5.3 0.1nm Mg2 ? Mg2 Index
37- 40 F4.2 --- db ? Distance of the corresponding point from the
boundary line of NaD-Mg2 diagram (1)
42- 45 F4.2 0.1nm Mgb ? Mgb index
47- 50 F4.2 --- dc ? Distance of the corresponding point from the
boundary line of NaD-Mgb diagram (1)
52- 55 F4.2 0.1nm CaMg ? CaMg index
57- 60 F4.2 --- dd ? Distance of the corresponding point from the
boundary line of NaD-CaMg diagram (1)
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Note (1): Subscripts a, b, c, and d correspond to (a), (b), (c), and (d)
in Fig. 8, respectively.
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Global notes:
Note (G1): Dimensionless distance:
d=[(D1/e1)2+(D2/e2)2]1/2
where D1, D2 and e1, e2 are the X and Y differences between the
boundary line and the star position and the observational errors of
the two indices in each diagram, respectively. See Sect. 4.1 for
details.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 06-Apr-2004