J/AJ/113/279 Proton Capture Chains. II (Kraft+ 1997)
Proton Capture Chains in Globular Cluster Stars. II. Oxygen, Sodium, Magnesium,
and Aluminum Abundances in M13 Giants Brighter than the Horizontal Branch
Kraft R.P., Sneden C., Smith G.H., Shetrone M.D., Langer G.E.,
Pilachowski C.A.
<Astron. J. 113, 279 (1997)>
=1997AJ....113..279K 1997AJ....113..279K
ADC_Keywords: Clusters, globular ; Stars, giant ; Abundances ;
Effective temperatures
Abstract:
Observations of 11 giants in the globular cluster M13 fainter than
M_V=-1.7 have been obtained with the High Resolution Echelle
Spectrograph on the Keck I Telescope. When combined with similar data
for brighter giants obtained with the 3.0-m Shane Telescope's Hamilton
Echelle spectrograph, these data allow examination of the detailed
abundances of oxygen, sodium, magnesium, and aluminium over a wide
range of luminosity on the red giant branch. We find that oxygen
depletions, correlated with sodium enhancements, can be found in
giants with luminosities down to nearly the level of the horizontal
branch at M_V=0.3. Aluminum abundances in M13 giants also span a wide
range (∼1.4dex) and are anticorrelated with the observed magnesium
abundances. However, field halo giants of comparable metallicity and
evolutionary state exhibit (normal) high abundances of O and Mg and
low abundances of Na and Al. Stars in M13 with high sodium and
aluminum and low oxygen and magnesium abundances are found at all
giant branch luminosities, as are stars with more normal light element
abundances (as defined by field halo stars of comparable metallicity).
The detailed abundance patterns of the light elements oxygen, sodium,
magnesium, and aluminum can be explained most easily as a result of
deep mixing and proton capture nucleosynthesis. Evidence in support of
this explanation is (a) the constancy of the abundances of Al+Mg and
C+N+O, (b) the shift in the distribution of sodium abundances toward
higher values and of oxygen abundances toward lower values in cluster
giants with surface gravities below log g=1.0. The action of deep
mixing, however, is seen not only at the top of the giant branch, but
already in some giants even as faint as the level of the horizontal
branch.
(Copyright) 1996 American Astronomical Society.
Description:
The tables described here contain equivalent width measurements that
were not reported in the printed version of the paper.
Objects:
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RA (2000) DE Designation(s)
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16 41 41.4 +36 27 37 M 13 = NGC 6205
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea.dat 82 54 KeckR45 Equivalent Widths for M13 Stars
tablea.tex 125 92 AASTeX version of tablea.dat
tableb.dat 62 69 HamR50 Equivalent Widths for M13 Stars
tableb.tex 93 102 AASTeX version of tableb.dat
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See also:
J/AJ/112/545 : Proton capture chains in glob. clusters. I. (Pilachowski+ 1996)
Byte-by-byte Description of file: tablea.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 0.1nm Lambda Wavelength of identified line
10- 14 A5 --- ID Line identification
16- 20 F5.2 eV EP Energy potential
22- 27 F6.2 --- log(gf) log of oscillator strength
29- 32 I4 --- K228 ? Equivalent width for M13 star K-228
34- 37 I4 --- K188 ? Equivalent width for M13 star K-188
39- 42 I4 --- L766 ? Equivalent width for M13 star L-766
44- 47 I4 --- L168 ? Equivalent width for M13 star L-168
49- 52 I4 --- L726 ? Equivalent width for M13 star L-726
54- 57 I4 --- L984 ? Equivalent width for M13 star L-984
59- 62 I4 --- L955 ? Equivalent width for M13 star L-955
64- 67 I4 --- L337 ? Equivalent width for M13 star L-337
69- 72 I4 --- L348 ? Equivalent width for M13 star L-348
74- 77 I4 --- L1062 ? Equivalent width for M13 star L-1062
79- 82 I4 --- L469 ? Equivalent width for M13 star L-469
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Byte-by-byte Description of file: tableb.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 F7.2 0.1nm Lambda Wavelength of identified line
10- 14 A5 --- ID Line identification
15- 20 F6.2 eV EP Energy potential
21- 27 F7.2 --- log(gf) log of oscillator strength
28- 32 I5 --- L598 ? Equivalent width for M13 star L-598
33- 37 I5 --- L629 ? Equivalent width for M13 star L-629
38- 42 I5 --- L194 ? Equivalent width for M13 star L-194
43- 47 I5 --- L973 ? Equivalent width for M13 star L-973
48- 52 I5 --- L954 ? Equivalent width for M13 star L-954
53- 57 I5 --- L835 ? Equivalent width for M13 star L-835
58- 62 I5 --- L70 ? Equivalent width for M13 star L-70
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Origin: AAS CD-ROM series, Volume 8, 1997 Lee Brotzman [ADS] 04-Apr-1997
Historical notes:
The name of stars L-766 to L-469 in tablea.dat was missprint (K instead of L).
Corrections were made on 05-Feb-1998.
(End) [CDS] 03-Jul-1997