J/AJ/156/6 Light element abundances of RGB & AGB stars in M10 (Gerber+, 2018)
Light element abundances and multiple populations in M10.
Gerber J.M., Friel E.D., Vesperini E.
<Astron. J., 156, 6-6 (2018)>
=2018AJ....156....6G 2018AJ....156....6G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, giant ; Radial velocities ;
Photometry, VRI ; Photometry, infrared ; Effective temperatures ;
Spectroscopy ; Abundances
Keywords: globular clusters: general - globular clusters: individual: M10 -
stars: abundances - stars: evolution - stars: Population II
Abstract:
We present CN and CH band measurements for 137 red giant branch (RGB)
and asymptotic giant branch (AGB) stars in the Galactic globular
cluster M10. Our measurements come from low-resolution spectroscopy
taken with the Hydra spectrograph on the WIYN-3.5 m telescope. We use
these measurements to identify two populations of stars within the
cluster, CN-normal and CN-enhanced, and find that in our sample 60% of
stars are CN-enhanced. Our large sample allows us to conduct a detailed
analysis on the carbon and nitrogen abundances and the radial distribution
of each population separately. Our analysis of the radial dependence shows
that each population has the same radial distribution in the cluster,
which is likely due to the cluster being dynamically evolved. We also
compare our results to other methods of classifying multiple populations
in globular clusters such as the Na-O anti-correlation and the HST
pseudo-color-magnitude diagrams. We find that these three methods of
identifying multiple populations are in good agreement with each other
for M10 and all lead to an estimate of the fraction of second-generation
stars approximately equal to 60%. Among AGB stars, when classified by
the CN band, there appears to be a lack of second-generation stars when
compared to the RGB stars. However, when classified by [N/Fe], we find
a similar 60% of AGB stars in the second generation. Finally, we use the
measured carbon and nitrogen abundances in RGB stars to study the change
of each element with magnitude as stars evolve up the RGB, comparing
the results to globular clusters of similar metallicity, M3 and M13.
Description:
We obtained 190 different spectra of stars within a 18' by 18' grid
around the center of M10 in two observation runs from 2014 August 1-4
to 2016 June 10-12 using the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5 m
Telescope and Hydra, a multi-object, fiber-fed bench spectrograph. The
bench spectrograph was used with the "600@10.1" grating, which resulted
in spectra with a ∼4.5 Å/pixel dispersion covering a range of
∼2800 Å. The spectra taken during the 2014 run were centered at a
wavelength of 4900 Å, while the spectra taken during the 2016 run
were centered at 5100 Å. Six different configurations of fibers were
necessary to obtain the full sample size.
Objects:
---------------------------------------------
RA (ICRS) DE Designation(s)
---------------------------------------------
16 57 09.05 -04 06 01.1 M 10 = NGC 6254
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 113 165 Stars measured in M10
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See also:
J/A+AS/145/223 : Proper motion data of M10 (Chen+, 2000)
J/ApJ/628/729 : CCD BVIc photometry of M10 stars (Pollard+, 2005)
J/A+A/505/117 : Abundances of red giants in 15 globular clusters
(Carretta+, 2009)
J/A+A/505/139 : Abundances of red giants in 17 globular clusters
(Carretta+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID [9/2787] Identifier from Pollard et al. (2005,
J/ApJ/628/729)
6- 14 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
16- 23 F8.5 deg DEdeg Declination in decimal degrees (J2000)
25- 30 F6.1 km/s HRV [-168/116] Heliocentric radial velocity
32- 36 F5.2 mag Vmag [11.85/17.6] Johnson V magnitude, Pollard et al.
(2005, J/ApJ/628/729)
38- 42 F5.2 mag VMag [-2.33/3.42] Absolute V magnitude (1)
44- 49 F6.2 mag Ksmag [-99.99/15.29] 2MASS Ks magnitude
51- 56 F6.1 K Teff [3800/6008] Stellar effective temperature
58- 61 F4.2 [cm/s2] logg [0.67/3.96] Stellar surface gravity
63- 68 F6.3 --- CN [-0.664/0.224] CN band strength
70- 75 F6.3 --- dCN [-0.288/0.501] δCN index strength
77- 81 F5.3 --- CH [0.013/0.367] CH band strength
83- 87 F5.2 [-] [C/Fe] [-1.62/0.5] Log C/Fe abundance
89- 93 F5.2 [-] [N/Fe] [-1.59/2.5] Log N/Fe abundance
95-100 F6.3 [-] [O/Fe] [-0.34/0.61]?=9.999 Log O/Fe abundance (3) (2)
102-107 F6.3 [-] [Na/Fe] [-0.519/0.754]?=9.999 Log Na/Fe abundance (3)
109-111 A3 --- Branch [RGB/AGB] Red giant branch in the V/B-V
color-magnitude diagram (CMD)
113 A1 --- Memb [y/n] Membership status (yes or no)
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Note (1): Derived assuming a distance modulus of (m-M)v=14.18.
Note (2): Smith et al. (2005AJ....129.1589S 2005AJ....129.1589S).
Note (3): Carretta et al. (2009, J/A+A/505/117; 2009, J/A+A/505/139)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 08-Jan-2019