scholarly journals L199, A NEW VARIABLE STAR IN M13

2021 ◽  
pp. 1-10
Author(s):  
Francisco Violat-Bordonau
Keyword(s):  
Variable Star ◽  
Variable Stars ◽  
Photometric Data ◽  
The Other ◽  
Giant Star ◽  
V Band ◽  
Period Estimation ◽  
Red Giant ◽  
Variability Data ◽  
Photometric Variation

During a routine study of the variable stars of Messier 13 (NGC 6205 = Cl 1639+365) we have discovered the variability of L199 (TYC 2588-1386-2), a red giant star member of the cluster: using the photometric data –in V band– obtained in the 2019 and 2020 campaigns we have verified its variability. Data from the Zwicky Transient Facility (ZTF) and Deras et al. (2019) were utilized to determine its type of variability and period estimation: our data suggest that it is a semiregular red giant, similar to the other variables of this type of the cluster, whose cycles of photometric variation are not identical; we derived a period of ~27 days (although without a regular periodicity) and an amplitude smaller: 0.08 ± 0.03 magnitudes in V band although they may be somewhat larger or smaller. With this discovery the cluster now has 63 variable stars.

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 Optical and Near-IR Monitoring of Symbiotic Binary Systems

2001 ◽  
Vol 183 ◽  
pp. 167-176
Author(s):  
Joanna Mikołajewska
Keyword(s):  
Binary Systems ◽  
Variable Stars ◽  
Type Star ◽  
Symbiotic Stars ◽  
Future Prospects ◽  
Dust Shell ◽  
Giant Star ◽  
Long Period ◽  
Near Ir ◽  
Red Giant

AbstractSymbiotic stars are long-period interacting binary systems in which an evolved red giant star transfers material to its much hotter compact companion. Such a composition places them among the most variable stars. In addition to periodic variations due to the binary motion, they often show irregular changes due to nova-like eruptions of the hot component. In some systems the cool giant is a pulsating Mira-type star usually surrounded by a variable dust shell. Here, I present results of optical and IR monitoring of symbiotic systems as well as future prospects for such studies.

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 Lithium in the Old Open Cluster NGC 2243

2000 ◽  
Vol 198 ◽  
pp. 293-298 ◽  
Author(s):  
V. Hill ◽  
L. Pasquini
Keyword(s):  
High Resolution ◽  
Globular Clusters ◽  
Open Cluster ◽  
Interesting Case ◽  
The Other ◽  
High Resolution Spectroscopy ◽  
Giant Star ◽  
Other Hand ◽  
Red Giant ◽  
The One

We report observations of lithium in a sample of 11 stars in the metal-poor open cluster NGC 2243, that were obtained from high-resolution spectroscopy at CASPEC (ESO 3.6m telescope). The targets are located at the turnoff region, plus one red giant star.NGC 2243 is one of the most metal-poor open cluster, almost as deficient as 47 Tuc, but substantially younger (∼4 Gyrs and [Fe/H]=-0.5 dex), which makes it a very interesting case to compare with more metal rich coeval clusters on the one hand, and old metal-rich globular clusters (47 Tuc) on the other hand. The preliminary Lithium abundances obtained are discussed in this framework.

D. The Line Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 207-244
Author(s):  
R. P. Kraft
Keyword(s):  
Variable Stars ◽  
The Other ◽  
Line Spectrum ◽  
Afternoon Session ◽  
Empirical Information ◽  
Pulsating Variable Stars ◽  
Almost Continuous ◽  
Informal Approach

(Ed. note:Encouraged by the success of the more informal approach in Christy's presentation, we tried an even more extreme experiment in this session, I-D. In essence, Kraft held the floor continuously all morning, and for the hour and a half afternoon session, serving as a combined Summary-Introductory speaker and a marathon-moderator of a running discussion on the line spectrum of cepheids. There was almost continuous interruption of his presentation; and most points raised from the floor were followed through in detail, no matter how digressive to the main presentation. This approach turned out to be much too extreme. It is wearing on the speaker, and the other members of the symposium feel more like an audience and less like participants in a dissective discussion. Because Kraft presented a compendious collection of empirical information, and, based on it, an exceedingly novel series of suggestions on the cepheid problem, these defects were probably aggravated by the first and alleviated by the second. I am much indebted to Kraft for working with me on a preliminary editing, to try to delete the side-excursions and to retain coherence about the main points. As usual, however, all responsibility for defects in final editing is wholly my own.)

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

FIRST RESULTS FROM TIEN-SHAN SURVEY TO SEARCH FOR VARIABLE STARS: LIGHTCURVE ANALYSIS AND VARIABLE STAR CLASSIFICATION

2020 ◽  
Vol 3 (331) ◽  
pp. 81-91
Author(s):  
Serebryanskiy A., ◽  
◽  
Aimanova G. K., ◽  
Kondratyeva L.N., ◽  
Omarov Ch., ◽  
...  
Keyword(s):  
Variable Star ◽  
Variable Stars ◽  
Tien Shan ◽  
First Results ◽  
Star Classification

scholarly journals K2-97b: A (RE-?)INFLATED PLANET ORBITING A RED GIANT STAR

2016 ◽  
Vol 152 (6) ◽  
pp. 185 ◽  
Author(s):  
Samuel K. Grunblatt ◽  
Daniel Huber ◽  
Eric J. Gaidos ◽  
Eric D. Lopez ◽  
Benjamin J. Fulton ◽  
...  
Keyword(s):  
Giant Star ◽  
Red Giant

Times of maximum of KZ Hya from OACS -UNAH

2020 ◽  
Vol 8 (2) ◽  
pp. 90-93
Author(s):  
M. Meza ◽  
A. Pineda ◽  
C. Argueta ◽  
Y. Mendoza ◽  
M. C. Pereira ◽  
...  
Keyword(s):  
Variable Star ◽  
Variable Stars ◽  
Surface Layers ◽  
Maximum Light ◽  
Photometric Observations

A pulsating variable star is one whose brightness changes periodically due to the expansion and contraction of the surface layers of the star. Several times of maximum light can be obtained in brief observations of SX Phoenicis variable stars due to their short periods of pulsation (P ~ 1:0 - 1:75 h). We report three new times of maximum light of SX Phoenicis star KZ Hya obtained from photometric observations made on the night of April 5-6, 2019 from the Observatorio Astronómico Centroaméricano de Suyapa (OACS) of the Universidad Nacional Autónoma de Honduras

scholarly journals The AAVSO and its Variable Star Databank on Pulsating Stars

1995 ◽  
Vol 155 ◽  
pp. 421-422 ◽  
Author(s):  
Janet A. Mattei
Keyword(s):  
Variable Star ◽  
American Association ◽  
Variable Stars ◽  
Pulsating Stars

AbstractThe American Association of Variable Stars Observers is the world’s largest organization of variable star observers. Its services to the astronomical community and database on pulsating variables are described.

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