scholarly journals Future of the General Catalogue of Variable Stars from the Experience of Recent Name-lists

2021 ◽  
Vol 30 (1) ◽  
pp. 122-126
Author(s):  
Nikolay N. Samus ◽  
Elena V. Kazarovets ◽  
Olga V. Durlevich ◽  
Natalia N. Kireeva ◽  
Elena N. Pastukhova ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Variable Star ◽  
Star Clusters ◽  
Positional Information ◽  
Variable Stars ◽  
Photometric Data ◽  
Star Data ◽  
General Catalogue ◽  
The Future ◽  
History Of

Abstract We briefly outline the history of the General Catalogue of Variable Stars (GCVS) and the New Catalogue of Suspected Variable Stars (NSV catalogue). Recently, we have completed a revision of the NSV catalogue. Positional information was checked for all its stars and, in many cases, new photometric data were added. As a result, one third of all NSV stars have been transferred to the GCVS. Having determined equatorial coordinates for variable stars in globular star clusters, we began to add them to the GCVS. Two Name-lists published so far contain more than 1700 variable stars in 36 globular clusters; an additional Name-list (about 900 variable stars in 27 globular clusters) will be published before the end of 2021. We discuss problem cases in the literature and in the Catalogue of Variable Stars in Galactic Globular Clusters revealed during our preparation of the Name-lists. The future of traditional catalogues of variable stars (GCVS; AAVSO Variable-star Data Index VSX) is discussed.

scholarly journals GCVS Problems with Flare Stars

1995 ◽  
Vol 151 ◽  
pp. 416-418
Author(s):  
Elena V. Kazarovets ◽  
Nikolai N. Samus
Keyword(s):  
Globular Clusters ◽  
Variable Star ◽  
Star Clusters ◽  
Fold Increase ◽  
Variable Stars ◽  
Star Clusters And Associations ◽  
The Past ◽  
The Status ◽  
Flare Stars ◽  
New Variables

The astrometric aspect of cataloguing variable stars becomes more and more important. During the past thirty years there has been approximately an three-fold increase of the number of known variables; now the rate of new discoveries becomes extremely high, and we may expect a new twofold increase in a couple of years due to discoveries made with space-borne instruments. To avoid confusion, we should continue our policy of naming new variables, and this is impossible without checking identifications with known variable stars, requiring good coordinates and/or finding charts. Operation of automatic telescopes also needs excellent coordinates just for pointing. For all these reasons, we are now working on improving considerably the accuracy standard of variable star coordinates, providing at least reasonably good coordinates for extragalactic variables (GCVS, 4th Edition, Vol. V, now in press, gives coordinates mainly to a second of arc) and variables in globular clusters, identifying variables, including those with rough published positions, with positional catalogues, etc.Flare stars are very important variables; potentially they are one of the most abundant types of variable stars. Their identification in minimum light may be rather complicated, especially for dense regions of star clusters and associations. Most regretfully, there are many cases of papers on flare stars introducing additional confusion connected with wrong designations, wrong coordinates, missing finding charts. Thus, there appear problems preventing us from incorporating some flare stars in the GCVS. Many definite variables remain in the status of “suspects”, being positionally close to known variables, and no finding chart being available either for the earlier known variable or for the new one. Sometimes we do include such a “pretender” into the GCVS, and years after a finding chart or good coordinates appear, and it turns out that we have two entries for the same star (see, for instance, numerous cases of duplicated names for flare stars in Taurus in the GCVS Vol. III).

scholarly journals Variable Stars in Dwarf Spheroidal Galaxies

1973 ◽  
Vol 21 ◽  
pp. 35-48
Author(s):  
Steven Van Agt
Keyword(s):  
Globular Clusters ◽  
Local Group ◽  
Elliptical Galaxies ◽  
Variable Stars ◽  
Dwarf Spheroidal Galaxies ◽  
Theoretical Predictions ◽  
History Of ◽  
Set Up ◽  
Theoretical Considerations ◽  
Spheroidal Galaxies

Interest in dwarf spheroidal galaxies is motivated by a number of reasons; an important one on the occasion of this colloquium is the abundance of variable stars. The theory of stellar evolution and stellar pulsations is now able to predict from theoretical considerations characteristic properties of variable stars in the colour-magnitude diagram (Iben, 1971). By observing the variable stars in the field, and in as wide a selection of objects as possible, more insight can be obtained into the history of the oldest members of our Galaxy (the globular clusters) and of the dwarf spheroidal galaxies in the Local Group. It is worthwhile to explore the spheroidal galaxies as observational tests for the theoretical predictions of conditions in space away from our Galaxy. The numbers of variable stars in the dwarf spheroidal galaxies are such that we may expect well-defined relations to emerge once reliable magnitude sequences have been set up, the variable stars found, and their periods determined. Six dwarf spheroidal galaxies are presently known in the Local Group within a distance of 250 kpc. In Table I, which lists members of the Local Group, they are at the low-luminosity end of the sequence of elliptical galaxies (van den Bergh, 1968).

scholarly journals Observations of low mass stars in clusters: Some constraints and puzzles for stellar evolution theory

1984 ◽  
Vol 105 ◽  
pp. 123-138
Author(s):  
R.D. Cannon
Keyword(s):  
Globular Clusters ◽  
Main Sequence ◽  
Star Clusters ◽  
Variable Stars ◽  
Open Clusters ◽  
Low Mass Stars ◽  
Theory Of Evolution ◽  
Theoretical Predictions ◽  
Low Mass ◽  
Red Giant

This review will attempt to do two things: (i) discuss some of the data which are available for testing the theory of evolution of low mass stars, and (ii) point out some problem areas where observations and theory do not seem to agree very well. This is of course too vast a field of research to be covered in one brief review, so I shall concentrate on one particular aspect, namely the study of star clusters and especially their colour-magnitude (CM) diagrams. Star clusters provide large samples of stars at the same distance and with the same age, and the CM diagram gives the easiest way of comparing theoretical predictions with observations, although crucial evidence is also provided by spectroscopic abundance analyses and studies of variable stars. Since this is primarily a review of observational data it is natural to divide it into two parts: (i) galactic globular clusters, and (ii) old and intermediate-age open clusters. Some additional evidence comes from Local Group galaxies, especially now that CM diagrams which reach the old main sequence are becoming available. For each class of cluster I shall consider successive stages of evolution from the main sequence, up the hydrogen-burning red giant branch, and through the helium-burning giant phase.

scholarly journals The Carina Dwarf Galaxy Variable Star Population

2002 ◽  
Vol 185 ◽  
pp. 134-135
Author(s):  
V. Ripepi ◽  
M. Dall’Ora ◽  
L. Pulone ◽  
M. Castellani ◽  
C. Corsi ◽  
...  
Keyword(s):  
Variable Star ◽  
Dwarf Galaxy ◽  
Variable Stars ◽  
Photometric Data ◽  
Wide Field ◽  
Preliminary Results

AbstractWe present some preliminary results based on new observations of the variable stars belonging to the Carina Dwarf Galaxy (DG). Photometric data were collected with the two wide field imagers available at ESO ([email protected].) and CTIO (4m prime focus).

scholarly journals Massive star clusters in galaxies

2010 ◽  
Vol 368 (1913) ◽  
pp. 889-906 ◽  
Author(s):  
William E. Harris
Keyword(s):  
Recent Work ◽  
Globular Clusters ◽  
Evolutionary History ◽  
Massive Star ◽  
Star Clusters ◽  
Star Cluster ◽  
Cluster System ◽  
History Of ◽  
Review Current

The ensemble of all star clusters in a galaxy constitutes its star cluster system . In this review, the focus of the discussion is on the ability of star clusters, particularly the systems of old massive globular clusters (GCs), to mark the early evolutionary history of galaxies. I review current themes and key findings in GC research, and highlight some of the outstanding questions that are emerging from recent work.

Variable star clusters. New variable stars.

1898 ◽  
Vol 7 ◽  
pp. 208 ◽  
Author(s):  
E. C. Pickering ◽  
S. I. Bailey ◽  
W. P. Fleming ◽  
E. F. Leland ◽  
L. D. Wells
Keyword(s):  
Variable Star ◽  
Star Clusters ◽  
Variable Stars

scholarly journals Stellar Evolution in Globular Clusters and HST

1988 ◽  
Vol 126 ◽  
pp. 443-454
Author(s):  
Alvio Renzini
Keyword(s):  
Stellar Evolution ◽  
Working Group ◽  
Globular Clusters ◽  
Hubble Space Telescope ◽  
Star Clusters ◽  
Space Telescope ◽  
The Future

Globular clusters (GC) have been regarded among the most obvious targets for the Hubble Space Telescope since the very first conception of this project, and some observational programs have been exemplified in publications concerning the future use of HST (e.g. Westphal 1982 and Macchetto 1982, in the “Patras Book”, Bahcall 1985, see also the 1985 Report of the STScI working group on Stars and Star Clusters).

Research Programs at the Carter Observatory: An Overview

1996 ◽  
Vol 13 (2) ◽  
pp. 162-164
Author(s):  
R. J. Dodd ◽  
W. Orchiston
Keyword(s):  
Binary Stars ◽  
Star Clusters ◽  
Variable Stars ◽  
Photometric System ◽  
Clusters Of Galaxies ◽  
Standard Star ◽  
Main Research ◽  
Research Programs ◽  
History Of

AbstractAn outline is given of the main research programs currently in progress at the Carter Observatory. These include: the establishment of a set of standard star magnitudes and colours in the Vilnius seven-colour photometric system; the study of galactic and extragalactic star clusters using Vilnius and broadband photometries; binary stars and the development of APTs; and the history of Australasian astronomy. The role of Carter Observatory Honorary Research Associates is described and mention is made of the joint New Zealand/Japan program to observe gravitational microlensing effects, discover variable stars and patrol selected clusters of galaxies for supernovae.

scholarly journals VISTA variable survey in the Milky Way

2009 ◽  
Vol 5 (S262) ◽  
pp. 287-290
Author(s):  
M. Hempel ◽  
D. Minniti ◽  
R. Saito ◽  
P. Pietrukowicz ◽  
P. W. Lucas
Keyword(s):  
Globular Clusters ◽  
Milky Way ◽  
Variable Stars ◽  
Open Clusters ◽  
Point Sources ◽  
Population Census ◽  
Cluster Evolution ◽  
Rr Lyrae ◽  
Public Survey ◽  
History Of

AbstractOver the next 5 years the VVV collaboration (Vista Variable in the Via Lactea) will conduct an extensive survey of the galactic bulge and disk in the near-IR, using the new VISTA telescope. This public survey covers a field of 520 sqr. deg, including not only regions of high star formation, but also 33 known globular clusters and ~350 open clusters. The final product will be a deep IR atlas in 5 passbands for ~109 point sources among which we expect 106 variable stars. These will be produce a 3-D map of the surveyed region using well-understood primary distance indicators such as RR Lyrae stars. The observations will be combined with data from MACHO, OGLE, EROS, VST, Spitzer, HST, Chandra, Integral, and ALMA for a complete understanding of the variable sources in the inner Milky Way. Several important implications for the history of the Milky Way, for globular cluster evolution, for the population census of the bulge and center, and for the pulsation theory will follow from this survey.

scholarly journals The Variable Star Population in the Center of 47 Tuc as denned by HST Observations

1995 ◽  
Vol 155 ◽  
pp. 335-336
Author(s):  
Ronald L. Gilliland ◽  
Peter D. Edmonds ◽  
Larry Petro ◽  
Abhijit Saha ◽  
Michael Shara
Keyword(s):  
Time Series ◽  
Globular Clusters ◽  
Variable Star ◽  
High Spatial Resolution ◽  
Variable Stars ◽  
Light Curves ◽  
Dynamic Evolution ◽  
Limited Time ◽  
Blue Stragglers ◽  
Breeding Grounds

AbstractThe high stellar densities at the centre of some globular clusters provide prolific breeding grounds for exotic stars, e.g., the 11 msec pulsars in 47 Tuc and numerous blue stragglers. The same high density of stars as viewed on the sky makes ground-based photometry problematic for variable star detection. Even a very few tight binaries can be of fundamental importance for the dynamic evolution of the cluster core. We present results of a continuous 40-hour sequence of U-band CCD exposures acquired with WF/PC on HST. The high spatial resolution coupled with a stable PSF allows nearly Poisson limited time series on some 20,000 stars. The 1000 second sampling and long coverage provide excellent sensitivity to W UMa and δ Scuti variations. Light curves are shown for selected variables and the relative frequencies of binary and variable stars are discussed.

Sign in / Sign up

Export Citation Format

Share Document