J/A+A/632/A55 Line list from Pal 13 sample stars (Koch+, 2019)
An outer shade of Pal:
Abundance analysis of the outer halo globular cluster Palomar 13
Koch A., Cote P.
<Astron. Astrophys. 632, A55 (2019)>
=2019A&A...632A..55K 2019A&A...632A..55K (SIMBAD/NED BibCode)
ADC_Keywords: Atomic physics ; Clusters, globular ; Abundances
Keywords: techniques: spectroscopic - stars: abundances - Galaxy: abundances -
Galaxy: evolution - Galaxy: halo -
globular clusters: individual: Palomar 13
Abstract:
At a Galactocentric distance of 27kpc, Palomar 13 is an old globular
cluster (GC) belonging to the outer halo. We present a chemical
abundance analysis of this remote system from high-resolution spectra
obtained with the Keck/HIRES spectrograph. Owing to the low
signal-to-noise ratio of the data, our analysis is based on a
coaddition of the spectra of 18 member stars. We are able to determine
integrated abundance ratios for 16 species of 14 elements, of
α-elements (Mg, Si, Ca, and Ti), Fe-peak (Sc, Mn, Cr, Ni, Cu,
and Zn), and neutron-capture elements (Y and Ba). While the mean Na
abundance is found to be slightly enhanced and halo-like, our method
does not allow us to probe an abundance spread that would be expected
in this light element if multiple populations are present in Pal 13.
We find a metal-poor mean metallicity of -1.91±0.05 (statistical)
±0.22 (systematic), confirming that Pal 13 is a typical metal-poor
representative of the outer halo. While there are some differences
between individual α-elements, such as halo-like Mg and Si
versus the mildly lower Ca and Ti abundances, the mean [α/Fe] of
0.34±0.06 is consistent with the marginally lower α
component of the halo field and GC stars at similar metallicity. We
discuss our results in the context of other objects in the outer halo
and consider which of these objects were likely accreted. We also
discuss the properties of their progenitors. While chemically, Pal 13
is similar to Gaia-Enceladus and some of its GCs, this is not
supported by its kinematic properties within the Milky Way system.
Moreover, its chemodynamical similarity with NGC 5466, a purported
progeny of the Sequoia accretion event, might indicate a common origin
in this progenitor. However, the ambiguities in the full abundance
space of this comparison emphasize the difficulties in unequivocally
labeling a single GC as an accreted object, let alone assigning it to
a single progenitor.
Description:
The data used in our work are part of the program described by Cote et
al. (2002ApJ...574..783C 2002ApJ...574..783C), which studied the internal dynamics of
outer halo GCs. Spectra of 30 RGB candidates were taken between August
1998 and August 1999 with the High Resolution Echelle Spectrometer
(HIRES) on the Keck I telescope with the C1 decker (0.86") and 1x2
binning. The resulting spectral resolution is 45000, and our spectra
cover a wavelength range of 4300-6720Å.
Target stars were selected by Cote et al. (2002ApJ...574..783C 2002ApJ...574..783C) from
the published color-magnitude diagrams (CMDs) of Ortolani et al.
(1985AJ.....90..473O 1985AJ.....90..473O, hereafter ORS) and their own photometry,
collected with Keck and the Canada-France-Hawaii Telescope (CFHT).
Details for the stars we used are listed in Table 1.
We employed the IRAF task splot to fit Gaussian profiles to the
individual lines. These line lists and EW measurements are reported in
Table 2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 78 18 Stellar properties
table2.dat 32 109 Line list
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Star Star name (1)
8 A1 --- n_Star [c] Note on Star (2)
10- 11 I2 h RAh Right ascension (J2000.0)
13- 14 I2 min RAm Right ascension (J2000.0)
16- 20 F5.2 s RAs Right ascension (J2000.0)
22 A1 --- DE- Declination sign (J2000.0)
23- 24 I2 deg DEd Declination (J2000.0)
26- 27 I2 arcmin DEm Declination (J2000.0)
29- 33 F5.2 arcsec DEs Declination (J2000.0)
35- 38 I4 s texp Exposure time
40- 41 I2 pix-1 S/N Signal-to-noise ration given at 6600Å
43- 46 F4.2 mag B-V B-V colour index
48- 52 F5.2 mag Vmag V magnitude
54- 58 F5.2 km/s HRV Heliocentric radial velocity
60- 63 F4.2 km/s e_HRV rm uncertainty oh HRV
65- 68 I4 K Teff Effective temperature
70- 73 F4.2 km/s vturb Microturbulent velocity
75- 78 F4.2 [cm/s2] logg Surface gravity
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Note (1): Stellar IDs from Ortolani et al. (1985AJ.....90..473O 1985AJ.....90..473O)
(ORS, Cl* Palomar 13 ORS NNN in Simnad) and
Cote et al. (2002ApJ...574..783C 2002ApJ...574..783C, Cl* Palomar 13 CDM NNN in Simbad).
Note (2): Note as follows:
c = AGB star. Neither foreground stars nor the variable star V2 from Cote
et al. (2002ApJ...574..783C 2002ApJ...574..783C) are listed here because they were not
included in the analysis.
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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 F8.3 0.1nm Wave Wavelength
10- 14 A5 --- Ion Ion designation
17- 21 F5.3 eV EP Excitation potential
23- 28 F6.3 [-] loggf Oscillator strength
30- 32 I3 10-13m EW ? Mean equivalent width (1)
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Note (1): In milli-Angstroems.
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Acknowledgements:
Andreas Koch, andreas.koch(at)uni-heidelberg.de
(End) Patricia Vannier [CDS] 24-Oct-2019