UBV photometry of RR Lyrae variables in the globular cluster NGC 6121 /M4/

1979 ◽  
Vol 84 ◽  
pp. 1542 ◽  
Author(s):  
C. Cacciari
Keyword(s):  
Globular Cluster ◽  
Rr Lyrae ◽  
Ubv Photometry

UBV Photometry of RR Lyrae Variables in the Globular Cluster M4

1979 ◽  
Vol 46 ◽  
pp. 347-354 ◽  
Author(s):  
Carla Cacciari
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Normal Metal ◽  
Red Giants ◽  
The Sun ◽  
Horizontal Branch ◽  
Dark Clouds ◽  
Rr Lyrae ◽  
Metal Abundance ◽  
Ubv Photometry

M4, one of the closest globular clusters to the Sun, presents some peculiar features that make it very interesting to study. The first C-M diagram, published by Greenstein (1939), showed a well populated blue-horizontal branch, a characteristic which usually, but not always, indicates low metal abundance (Hartwick 1968). Kinman (1959) found however that it contains strong lined red giants and classified it as type A, indicating normal metal abundance. More recent C-M diagrams (Moshkalev 1975, Alcaino 1975, Lee 1977, Lloyd Evans 1977) substantially confirmed both these characteristics.One of the major problems in the study of this cluster is the high and possibly non-uni form reddening, due to its location behind the Scorpius-Ophiuchus dark clouds.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

scholarly journals The RR Lyrae variables in the globular cluster M68

1993 ◽  
Vol 412 ◽  
pp. 183 ◽  
Author(s):  
Christine M. Clement ◽  
Stephen Ferance ◽  
Norman R. Simon
Keyword(s):  
Globular Cluster ◽  
Rr Lyrae

On the mixed-mode RR lyrae variables in the globular cluster Ic 4499

1987 ◽  
pp. 230-232 ◽  
Author(s):  
Christine M Clement ◽  
James M Nemec ◽  
R J Dickens ◽  
Elizabeth A Bingham
Keyword(s):  
Globular Cluster ◽  
Mixed Mode ◽  
Rr Lyrae

scholarly journals A Century in Period Changes of the Variables in M15

1995 ◽  
Vol 155 ◽  
pp. 387-388
Author(s):  
Katalin Barlai ◽  
B. Szeidl
Keyword(s):  
Globular Cluster ◽  
Period Change ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Lyrae Stars ◽  
Linear Period

AbstractPeriod behaviour of 62 RR Lyrae stars in the M15 globular cluster has been investigated. About one half of the sample (30 stars) exhibited linear period change. The remaining 32 variables can be characterized by abrupt or erratic changes in their periods.

scholarly journals CCD Observations of Variable Stars in Globular Clusters

1989 ◽  
Vol 111 ◽  
pp. 285-285
Author(s):  
H.A. Smith ◽  
J.R. Kuhn ◽  
J. Curtis
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Variable Stars ◽  
Michigan State University ◽  
State University ◽  
Ccd Photometry ◽  
Rr Lyrae ◽  
Short Period ◽  
Ccd Observations ◽  
Period Variable

AbstractBVR observations of the relatively metal-rich globular cluster NGC 6388 have been obtained with a CCD on the CTIO 0.9 m telescope. Eighteen possible short period variable stars have been discovered in or near the cluster. At least 10 of these are probable RR Lyrae members of NGC 6388. We confirm the finding of Hazen and Hesser that this cluster is one of the most metal-rich to contain a significant number of RR Lyraes. A program of CCD photometry of field and cluster variable stars has been initiated on the 0.6m telescope of the Michigan State University Observatory.

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

Double-Mode RR Lyrae Stars in the Globular Cluster M15

1995 ◽  
Vol 110 ◽  
pp. 1712 ◽  
Author(s):  
Patricia Purdue ◽  
N. A. Silbermann ◽  
Pamela Gay ◽  
Horace A. Smith
Keyword(s):  
Globular Cluster ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Lyrae Stars

The RR Lyrae stars in and around the LMC globular cluster NGC 2257

1985 ◽  
Vol 57 ◽  
pp. 287 ◽  
Author(s):  
J. M. Nemec ◽  
J. E. Hesser ◽  
P. P. Ugarte
Keyword(s):  
Globular Cluster ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Lyrae Stars
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