On the intrinsic widths of the subgiant and horizontal branch sequences in the globular cluster M3

1982 ◽  
Vol 87 ◽  
pp. 537 ◽  
Author(s):  
A. Sandage ◽  
B. Katem
Keyword(s):  
Globular Cluster ◽  
Horizontal Branch

Supra–Horizontal‐Branch Stars and Population Gradients in the Galactic Center Globular Cluster NGC 6522

1998 ◽  
Vol 495 (2) ◽  
pp. 796-803 ◽  
Author(s):  
M. M. Shara ◽  
L. Drissen ◽  
R. M. Rich ◽  
F. Paresce ◽  
I. R. King ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Galactic Center ◽  
Horizontal Branch ◽  
Horizontal Branch Stars

scholarly journals Two PopII Cepheids in the Globular Cluster M10

1985 ◽  
Vol 82 ◽  
pp. 260-261 ◽  
Author(s):  
C. Clement ◽  
H. Sawyer Hogg ◽  
K. Lake
Keyword(s):  
Globular Cluster ◽  
Horizontal Branch ◽  
Carnegie Institution ◽  
University Of Toronto ◽  
The Third ◽  
Irregular Variable ◽  
Carnegie Institution Of Washington ◽  
The University

The globular cluster Messier 10 has three known variables. The first two of these were discovered by one of us (Sawyer 1933) and the third by Arp (1955). Two of the variables, V2 (P=18.7226) and V3 (P=7.831), are population II cepheids while V1 appears to be an irregular variable. Another star which lies in the Schwarzschild gap on the horizontal branch is a suspected variable (Voroshilov 1971).In this investigation, we examine the variations in the periods of the two cepheids over the interval 1912 to 1983 (for V2) and 1931 to 1983 (for V3). The study is based on photographs obtained with seven different telescopes - the Mt.Wilson 100-inch and 60-inch (1912 to 1919), the Dominion Astrophysical Observatory 72-inch, the David Dunlap 74-inch and 19-inch, the 16-inch at the University of Toronto downtown campus and the University of Toronto 24-inch at the Las Campanas Observatory of the Carnegie Institution of Washington. Some of our magnitudes have already been published (Sawyer 1938) and the remaining ones will be submitted to the Astronomical Journal for publication. We have also included material published by Arp (1955, 1957) in our study.

scholarly journals The HST large programme on NGC 6752 – III. Detection of the peak of the white dwarf luminosity function

2019 ◽  
Vol 488 (3) ◽  
pp. 3857-3865
Author(s):  
L R Bedin ◽  
M Salaris ◽  
J Anderson ◽  
M Libralato ◽  
D Apai ◽  
...  
Keyword(s):  
Globular Cluster ◽  
White Dwarf ◽  
Luminosity Function ◽  
Main Sequence ◽  
Hubble Space Telescope ◽  
Horizontal Branch ◽  
Space Telescope

ABSTRACT We report on the white dwarf (WD) cooling sequence of the old globular cluster NGC 6752, which is chemically complex and hosts a blue horizontal branch. This is one of the last globular cluster WD cooling sequences accessible to imaging by the Hubble Space Telescope. Our photometry and completeness tests show that we have reached the peak of the luminosity function of the WD cooling sequence, at a magnitude mF606W  = 29.4 ± 0.1, which is consistent with a formal age of ∼14 Gyr. This age is also consistent with the age from fits to the main-sequence turn-off (13–14 Gyr), reinforcing our conclusion that we observe the expected accumulation of WDs along the cooling sequence.

scholarly journals Multivariate analysis of globular cluster horizontal branch morphology: searching for the second parameter

2006 ◽  
Vol 452 (3) ◽  
pp. 875-884 ◽  
Author(s):  
A. Recio-Blanco ◽  
A. Aparicio ◽  
G. Piotto ◽  
F. De Angeli ◽  
S. G. Djorgovski
Keyword(s):  
Multivariate Analysis ◽  
Globular Cluster ◽  
Horizontal Branch ◽  
Branch Morphology

M75, A Globular Cluster with a Trimodal Horizontal Branch. II.BVPhotometry of the RR Lyrae Variables

2003 ◽  
Vol 125 (5) ◽  
pp. 2543-2558 ◽  
Author(s):  
T. M. Corwin ◽  
M. Catelan ◽  
H. A. Smith ◽  
J. Borissova ◽  
F. R. Ferraro ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Horizontal Branch ◽  
Rr Lyrae

scholarly journals Short Period Variables in the Magellanic Cloud Cluster NGC 1466

1973 ◽  
Vol 21 ◽  
pp. 113-119 ◽  
Author(s):  
M. V. Norris
Keyword(s):  
Globular Cluster ◽  
Metal Content ◽  
Globular Clusters ◽  
Magellanic Clouds ◽  
Horizontal Branch ◽  
A Value ◽  
Short Period ◽  
Magnitude Diagram ◽  
The Galaxy ◽  
Metal Abundance

NGC 1466 (α1950 = 3h44.m6, δ1950= -71°45’) is a globular cluster which appears to be situated between the two Magellanic Clouds. Previous estimates (Gascoigne, 1966) put it at roughly the same distance from us as the LMC, so it is regarded as a member of the Cloud system. It is globular in appearance, and its colour-magnitude diagram confirms this classification. It has a fairly well-developed horizontal branch, and was found by Wesselink (1970) to be quite rich in variables. The metallicity index, Q, (van den Bergh, 1967) has a value of -0.36 for NGC 1466 (Andrews and Lloyd Evans, 1971). This would rank it with M5 and NGC 6171 as a cluster of intermediate metal content. This comparison is consistent with the value of Δ V for the cluster, which, at 2.m6, is representative of the Δ V values of globular clusters of intermediate metal abundance in the Galaxy.

scholarly journals The Influence of Rotation on Horizontal Branch Stars and on RR Lyrae Pulsational Properties

1981 ◽  
Vol 93 ◽  
pp. 275-275
Author(s):  
V. Castellani
Keyword(s):  
Globular Cluster ◽  
Main Sequence ◽  
Horizontal Branch ◽  
Structural Variations ◽  
Rr Lyrae ◽  
Horizontal Branch Stars ◽  
Mass Size ◽  
Red Giant

The occurrence of rotation in Globular Cluster stars has been suggested (see e.g. Renzini 1977) as a mechanism producing the observed colour spread in actual Horizontal Branches. If this is the case, canonical results on evolutionary properties of HB stars have to be revisited in order to account for rotation-driven structural variations: faster Main Sequence rotators delay the He flash increasing the mass-size Mc of the He core at the flash and loosing a greater amount of mass during the Red Giant stage.

scholarly journals Pal 1: A Globular Cluster Anyway?

1995 ◽  
Vol 164 ◽  
pp. 395-395
Author(s):  
J. Borissova ◽  
N. Spassova
Keyword(s):  
Globular Cluster ◽  
Luminosity Function ◽  
Main Sequence ◽  
Structural Parameters ◽  
Distance Modulus ◽  
Horizontal Branch ◽  
Ccd Photometry ◽  
Horizontal Branch Stars ◽  
Mass Estimate

CCD photometry of the halo cluster Pall in Thuan-Gunn system is presented. The color - magnitude diagrams (Fig. 1) show a well defined red horizontal branch, lower giant branch and main-sequence down to about two magnitudes below the main-sequence turnoff. The giant branch is absent and the brightest stars are horizontal-branch stars. The horizontal branch is composed of red stars only. The age of the cluster, determined by comparison with the isochrones of Bell and Vanden Berg (1987) is consistent with an age between 12 – 14 Gyr. and a metallicity [Fe/H] = −0.79. The observed luminosity function shows a deficiency of stars from about 0.5 mag below turnoff up to g = 21 mag. A distance modulus of (m – M)g0 = 15.35 ± 0.1 magnitude has been derived. An estimate of the cluster structural parameters gives rc = 1.7 pc and c = 1.46. A mass estimate of 1.6 × 103M⊙ and mass-to-light ratio 1.77 has been obtained, using King's (1966) method.

scholarly journals Evolutionary Aspects of the CMD of NGC 6553

1995 ◽  
Vol 164 ◽  
pp. 407-407
Author(s):  
M. Catelan ◽  
B. Barbuy ◽  
J. A. De Freitas Pacheco ◽  
S. Ortolani ◽  
E. Bica
Keyword(s):  
Chemical Evolution ◽  
Globular Cluster ◽  
Helium Abundance ◽  
Horizontal Branch ◽  
Red Giant ◽  
The One ◽  
Evolutionary Aspects ◽  
Tilted Models

We have investigated the V, B – V “clump” morphology of the globular cluster NGC 6553 (Ortolani et al. 1990, OBB90) through synthetic horizontal branch (SHB) models. Catelan's (1993) computations were extended to more metal-rich compositions, following Sweigart (1987) and Castellani et al. (1991), and transposed to the observational plane on the basis of VandenBerg's (1992) colour transformations and bolometric corrections. Observational scatter has also been added. In general, the SHB models are very clumpy, unlike the observed feature, which seems extended and peculiarly tilted. However, for particular combinations of helium abundance, metallicity, and mean mass on the HB, tilted models result, being however significantly less sloped and wider than observed. The NGC 6553 field is differentially reddened by ΔE(B – V) ≈ 0.06 (OBB90), which has been modelled, but which implies a CMD scatter which is smaller than the one originating from evolution away from the zero-age HB alone. We have also investigated the age of the cluster (ΔV method) and location of the red giant branch “bump,” in comparison with 47 Tuc. Since the helium and α-elements abundances are not known for NGC 6553, three chemical evolution scenarios have been considered, following the method of de Freitas Pacheco (1993). Details can be found elsewhere (Catelan et al. 1994).

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