The Relation between Near-infrared Luminosity of Red Giant Branch Bumps and Metallicity of Galactic Globular Clusters

2002 ◽  
Vol 124 (2) ◽  
pp. 977-988 ◽  
Author(s):  
Dong-Hwan Cho ◽  
Sang-Gak Lee
Keyword(s):  
Globular Clusters ◽  
Near Infrared ◽  
Galactic Globular Clusters ◽  
Red Giant

scholarly journals Near Infrared Photometry of New Galactic Globular Clusters GC 01 and GC 02

2002 ◽  
Vol 207 ◽  
pp. 107-109 ◽  
Author(s):  
J. Borissova ◽  
V. D. Ivanov ◽  
L. Vanzi
Keyword(s):  
Globular Cluster ◽  
Preliminary Report ◽  
Globular Clusters ◽  
Surface Brightness ◽  
Near Infrared ◽  
Infrared Photometry ◽  
Galactic Globular Clusters ◽  
Red Giant ◽  
Best Fit ◽  
Calculated Distance

We present a preliminary report on the first deep near infrared photometry of 2MASS GC 01 and 2MASS GC 02 - new Galactic globular cluster candidates, discovered by the 2MASS. The red giant branch slopes yielded [Fe/H]=-0.42 ± 0.15 dex and [Fe/H]=-0.66 ± 0.17 dex, respectively for GC 01 and GC 02. We estimated the reddening towards GC 01 and GC 02: E(B - V) = 5.36 ± 0.20, and E(B - V) = 4.55 ± 0.17. The calculated distance moduli to the clusters are: (m - M)0 = 13.53 ± 0.27 and (m - M)0 = 14.53 ± 0.31 for GC 01 and GC 02. Our best fit for the radial surface brightness profile of GC 02 yields: lg(rc) = 1.40, lg(rh) = 1.54, lg(rt) = 1.31, and c=1.60. CC 01 is less concentrated: lg(rc) = 1.63, lg(rh) = 1.7, lg(rt) = 1.25, and c=1.41.

scholarly journals WIDE FIELD NEAR-INFRARED PHOTOMETRY OF 12 GALACTIC GLOBULAR CLUSTERS: OBSERVATIONS VERSUS MODELS ON THE RED GIANT BRANCH

2015 ◽  
Vol 150 (6) ◽  
pp. 176 ◽  
Author(s):  
Roger E. Cohen ◽  
Maren Hempel ◽  
Francesco Mauro ◽  
Douglas Geisler ◽  
Javier Alonso-Garcia ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Near Infrared ◽  
Wide Field ◽  
Infrared Photometry ◽  
Galactic Globular Clusters ◽  
Red Giant

scholarly journals Narrow-Band Photometry of Red Variables in Globular Clusters

1973 ◽  
Vol 21 ◽  
pp. 164-177
Author(s):  
Robert F. Wing
Keyword(s):  
Radial Velocity ◽  
Globular Clusters ◽  
Near Infrared ◽  
Narrow Band ◽  
Small Range ◽  
Mira Variables ◽  
Color System ◽  
Red Giant ◽  
M Stars

AbstractFourteen red variables in the southern globular clusters 47 Tuc, ω Cen, and NGC 362 have been observed on an eight-color system of narrow-band photometry in the near infrared. Temperatures are derived from blackbody fits to the calibrated fluxes, and spectral types are given for the M stars. The types observed for the three Mira variables in 47 Tuc range from M3.1 to M7.5; two small-range variables in the same cluster are later than M4. The variables in ω Cen are mostly earlier than K5, but spectra of types M3 and MO were also encountered among radial-velocity members. In both the metal-rich 47 Tuc and the metal-poor ω Cen, the relation between TiO band strength and temperature is approximately normal. Several of these stars fall well above or below the red giant branches of their clusters in diagrams of infrared magnitude against temperature. Comparisons are made with recent results obtained at Radcliffe Observatory on some of the same stars.

scholarly journals The multipopulation phenomenon in Galactic globular clusters: M4 and M22

2009 ◽  
Vol 5 (S266) ◽  
pp. 326-332
Author(s):  
S. Villanova ◽  
G. Piotto ◽  
A. F. Marino ◽  
A. P. Milone ◽  
A. Bellini ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectroscopic Data ◽  
Globular Clusters ◽  
Stellar Population ◽  
The Other ◽  
Wide Field ◽  
Galactic Globular Clusters ◽  
Red Giant ◽  
Process Elements ◽  
Different Characteristics

AbstractWe present an abundance analysis based on high-resolution spectra of red-giant-branch (RGB) stars in the Galactic globular clusters NGC 6121 (M4) and NGC 6656 (M22). Our aim was to study their stellar population in the context of the multipopulation phenomenon recently discovered to affect some globular clusters. Analysis was performed for the following elements: O, Na, Mg, Al, Ca, Fe, Y, and Ba. Spectroscopic data were completed by high-precision wide-field U BV IC ground-based photometry and HST/ACS observations. For M4, we find a well-defined Na–O anticorrelation composed of two distinct groups of stars with significantly different Na and O content. The two groups of Na-rich and Na-poor stars populate two different regions along the RGB. As regards M22, Na and O follow the well-known anticorrelation found in many other GCs. However, at odds with M4, it appears to be continuous without any hint of clumpiness. On the other hand, we identified two clearly separated groups of stars with significantly different abundances of the s-process elements Y, Zr and Ba. The relative numbers of the members of both groups are very similar to the ratio of the stars in the two subgiant branches of M22 recently found by Piotto (2009). The s-element-rich stars are also richer in iron and have higher Ca abundances. This makes M22 the second cluster after ω Centauri where an intrinsic spread in Fe was found. Both spectroscopic and photometric results imply the presence of two stellar populations in M4 and M22, even if both clusters have completely different characteristics.

scholarly journals THE CHEMICAL COMPOSITION OF RED GIANT BRANCH STARS IN THE GALACTIC GLOBULAR CLUSTERS NGC 6342 AND NGC 6366

2016 ◽  
Vol 152 (1) ◽  
pp. 21 ◽  
Author(s):  
Christian I. Johnson ◽  
Nelson Caldwell ◽  
R. Michael Rich ◽  
Catherine A. Pilachowski ◽  
Tiffany Hsyu
Keyword(s):  
Chemical Composition ◽  
Globular Clusters ◽  
Galactic Globular Clusters ◽  
Red Giant ◽  
Giant Branch Stars

scholarly journals The magnitude difference between the main sequence turn off and the red giant branch bump in Galactic globular clusters

2011 ◽  
Vol 527 ◽  
pp. A59 ◽  
Author(s):  
S. Cassisi ◽  
A. Marín-Franch ◽  
M. Salaris ◽  
A. Aparicio ◽  
M. Monelli ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Main Sequence ◽  
Galactic Globular Clusters ◽  
Red Giant ◽  
Magnitude Difference

scholarly journals Facing problems in the determination of stellar temperatures and gravities: Galactic globular clusters

2020 ◽  
Vol 640 ◽  
pp. A87 ◽  
Author(s):  
A. Mucciarelli ◽  
P. Bonifacio
Keyword(s):  
Low Temperatures ◽  
Globular Clusters ◽  
Simple Relation ◽  
Spectroscopic Parameters ◽  
Giant Stars ◽  
Excitation Potential ◽  
Galactic Globular Clusters ◽  
Stellar Temperatures ◽  
Red Giant ◽  
Photometric Scale

We analysed red giant branch stars in 16 Galactic globular clusters, computing their atmospheric parameters both from the photometry and from excitation and ionisation balances. The spectroscopic parameters are lower than the photometric ones and this discrepancy increases with decreasing metallicity, reaching differences of ~350 K in effective temperature and ~1 dex in surface gravity at [Fe/H] ~ –2.5 dex. We demonstrate that the spectroscopic parameters are inconsistent with the position of the stars in the colour-magnitude diagram, providing overly low temperatures and gravities, and predicting that the stars are up to about 2.5 magnitudes brighter than the observed magnitudes. The parameter discrepancy is likely due to inadequacies in the adopted physics; in particular the assumption of a one-dimensional geometry could be the origin of the observed slope between iron abundances and excitation potential that leads to low temperatures. However, the current modelling of 3D/NLTE radiative transfer for giant stars seems to be unable to totally erase this slope. We conclude that the spectroscopic parameters are incorrect for metallicity lower than –1.5 dex and that photometric temperatures and gravities should be adopted for these red giant stars. We provide a simple relation to correct the spectroscopic temperatures in order to put them onto a photometric scale.

scholarly journals Lithium on the lower red giant branch of five Galactic globular clusters

2021 ◽  
Author(s):  
C. Aguilera-Gómez ◽  
L. Monaco ◽  
A. Mucciarelli ◽  
M. Salaris ◽  
S. Villanova ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Galactic Globular Clusters ◽  
Red Giant
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