J/AJ/141/175 Abundances in M15 RGB/RHB stars (Sobeck+, 2011)
The abundances of neutron-capture species in the very metal-poor globular
cluster M15: a uniform analysis of red giant branch and red horizontal branch
stars.
Sobeck J.S., Kraft R.P., Sneden C., Preston G.W., Cowan J.J., Smith G.H.,
Thompson I.B., Shectman S.A., Burley G.S.
<Astron. J., 141, 175 (2011)>
=2011AJ....141..175S 2011AJ....141..175S
ADC_Keywords: Clusters, globular ; Stars, giant ; Abundances
Keywords: globular clusters: individual (M15) - radiative transfer -
stars: abundances - stars: horizontal-branch - stars: late-type
Abstract:
The globular cluster M15 is unique in its display of star-to-star
variations in the neutron-capture elements. Comprehensive abundance
surveys have been previously conducted for handfuls of M15 red giant
branch (RGB) and red horizontal branch (RHB) stars. No attempt has
been made to perform a single, self-consistent analysis of these
stars, which exhibit a wide range in atmospheric parameters. In the
current effort, a new comparative abundance derivation is presented
for three RGB and six RHB members of the cluster. The analysis employs
an updated version of the line transfer code MOOG, which now
appropriately treats coherent, isotropic scattering.
Description:
For the three RGB stars of the M15 cluster, the re-analysis of two
sets of high-resolution spectra was performed: the first from Sneden
et al. (1997AJ....114.1964S 1997AJ....114.1964S) with approximate wavelength coverage
region of 5400Å≲λ≲6800Å and the second from Sneden et
al. (2000ApJ...536L..85S 2000ApJ...536L..85S) with a wavelength domain of
3600Å≲λ≲5200Å. All spectral observations were acquired
with the High Resolution Echelle Spectrometer at the Keck I 10.0m
telescope (with a spectral resolving power of
R=λ/δλ~=45000).
Objects:
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RA (J2000) Dec Designation(s)
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21 29 54.93 +12 13 22.6 K341 = NGC 7078 341
21 29 56.67 +12 09 46.3 K462 = NGC 7078 462
21 29 58.57 +12 09 21.4 K583 = NGC 7078 583
21 30 00.28 +12 14 25.0 B009 = Cl* NGC 7078 BBFP 009
21 29 56.38 +12 10 29.1 B028 = Cl* NGC 7078 BBFP 028
21 29 49.42 +12 11 21.9 B224 = Cl* NGC 7078 BBFP 224
21 30 07.30 +12 10 50.7 B262 = Cl* NGC 7078 BBFP 262
21 30 01.47 +12 10 04.2 B412 = Cl* NGC 7078 BBFP 412
21 30 01.11 +12 07 15.1 B584 = Cl* NGC 7078 BBFP 584
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 111 9 Photometry and model atmosphere parameters
table2.dat 197 310 Element abundances for individual transitions in
M15 RGB (red giant branch) stars
table3.dat 191 292 Element abundances for individual transitions in
M15 RHB (red horizontal branch) stars
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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- 4 A4 --- Name Star name
6- 10 F5.2 mag Vmag V magnitude (1)
12- 16 F5.3 mag V-K V-K colour index (2)
18- 21 I4 K Teff Effective temperature from Current-PHOTO (3)
23- 26 F4.2 [cm/s2] logg Surface gravity from Current-PHOTO (3)
28- 31 I4 K Teff2 Effective temperature from Current-SPEC
33- 36 F4.2 [cm/s2] logg2 Surface gravity from Current-SPEC
38- 42 F5.2 [-] [M/H]2 Metallicity from Current-SPEC
44- 47 F4.2 km/s Vturb2 Microturbulent velocity from Current-SPEC
49- 52 I4 K Teff3 Effective temperature from Previous-SPEC (4)
54- 57 F4.2 [cm/s2] logg3 Surface gravity from Previous-SPEC (4)
59- 63 F5.2 [-] [M/H]3 Metallicity from Previous-SPEC (4)
65- 68 F4.2 km/s Vturb3 Microturbulent velocity from Previous-SPEC (4)
70- 73 I4 K Teff4 ? Effective temperature from Previous-SPEC (4)
75- 78 F4.2 [cm/s2] logg4 ? Surface gravity from Previous-SPEC (4)
80- 84 F5.2 [-] [M/H]4 ? Metallicity from Previous-SPEC (4)
86- 89 F4.2 km/s Vturb4 ? Microturbulent velocity from Previous-SPEC (4)
91-111 A21 --- SName Simbad name
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Note (1): The RGB V magnitudes are taken from K.M. Cudworth (2011, private
communication) and those for the RHB targets are obtained from
Buonanno et al. (1983A&AS...51...83B 1983A&AS...51...83B).
Note (2): The K magnitudes for all members of the M15 data set are taken
from the 2MASS database (Skrutskie et al. 2006, Cat. VII/233).
Note (3): These values are derived with the IRFM effective temperature
formulations (Equations (8) and (9)) of Alonso et al.
(1999A&AS..140..261A 1999A&AS..140..261A).
Note (4): The previous values for the spectroscopic parameters for the RGB
stars are taken from Sneden et al. (2000ApJ...536L..85S 2000ApJ...536L..85S,
1997AJ....114.1964S 1997AJ....114.1964S), respectively, and those for the RHB stars are
obtained from Preston et al. (2006, Cat. J/AJ/132/85).
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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- 8 A8 --- Ion Element/Ionization state
10- 13 F4.1 --- Species Species (atomic number and ionization stage)
15- 19 A5 --- Meth Measurement type: EW or SYNTH
21 A1 --- u_lambda [~] An approximate flag on lambda
23- 30 F8.3 0.1nm lambda Wavelength; in Angstroms
32- 36 F5.3 eV chi ? Excitation potential
38- 44 F7.3 [-] log(gf) ? Log of the oscillator strength
48- 49 A2 --- l_logeK341 [≤ ] Limit flag on logeK341
52- 56 F5.2 [-] logeK341 ? Log of number abundance in K341 ε
60- 61 A2 --- l_logeK462 [≤ ] Limit flag on logeK341
64- 68 F5.2 [-] logeK462 ? Log of number abundance in K462 ε
72- 73 A2 --- l_logeK583 [≤ ] Limit flag on logeK341
76- 80 F5.2 [-] logeK583 ? Log of number abundance in K583 ε
82-197 A116 --- r_log(gf) Reference for log(gf)
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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- 5 A5 --- Ion Element/Ionization state
7- 10 F4.1 --- Species Species (atomic number and ionization stage)
12- 16 A5 --- Meth Measurement type: EW or SYNTH
18- 25 F8.3 0.1nm lambda Wavelength; in Angstroms
27- 31 F5.3 eV chi Excitation potential
33- 38 F6.3 [-] log(gf) Log of the oscillator strength
40- 44 F5.2 [-] logeB009 ? Log of number abundance in B009 ε
46- 50 F5.2 [-] logeB028 ? Log of number abundance in B028 ε
52- 56 F5.2 [-] logeB224 ? Log of number abundance in B224 ε
58- 62 F5.2 [-] logeB262 ? Log of number abundance in B262 ε
64- 68 F5.2 [-] logeB412 ? Log of number abundance in B412 ε
70- 74 F5.2 [-] logeB584 ? Log of number abundance in B584 ε
76-191 A116 --- r_log(gf) Reference for log(gf)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 07-Sep-2012