scholarly journals Variability study of the FBS M giants

2021 ◽  
pp. 478-483
Author(s):  
K. S. Gigoyan ◽  
G. R. Kostandyan
Keyword(s):  
Light Curves ◽  
Late Type ◽  
Data Bases ◽  
Byurakan Survey ◽  
Distance Information ◽  
Long Period ◽  
Sky Survey ◽  
Variability Study ◽  
Variability Data ◽  
Galactic Distribution

We study in this paper variability of the late-type M giants found in the First Byurakan Survey (FBS) spectroscopic data base. We used phase dependent light – curves from large sky area variability data bases such as Catalina Sky Survey (CSS) and All-Sky Automated Survey for Supernovae (ASAS-SN). We used also the distance information derived from Gaia EDR3 to construct the Galactic distribution of the M – type giants from the second edition of the FBS Late-Type Stars catalogue including various kinds of long period variables.

New results for FBS late-type stars using Gaia EDR3 data

2021 ◽  
Vol 38 ◽  
Author(s):  
Kamo S. Gigoyan ◽  
T. Lebzelter ◽  
G. R. Kostandyan ◽  
E. Karapetyan ◽  
D. Baghdasaryan ◽  
...  
Keyword(s):  
Absolute Magnitude ◽  
Light Curves ◽  
Late Type ◽  
Data Bases ◽  
Byurakan Survey ◽  
The Third ◽  
Sky Survey ◽  
Magnitude Diagram ◽  
Astrometric Data ◽  
Variability Data

Abstract We study in this paper bright late-type giants found in the First Byurakan Survey (FBS) data base. Phase dependent light-curves from large sky area variability data bases such as Catalina Sky Survey (CSS) and All-Sky Automated Survey for Supernovae (ASAS-SN), and the early installment of the third Gaia data release (Gaia EDR3) photometric and astrometric data have been used to characterize our sample of 1 100 M-type giants and 130 C-type stars found at high latitudes. Gaia radial velocities (RV) are available for 134 and luminosities for 158 stars out of 1 100. We show the behaviour of our sample stars in a Gaia color–absolute magnitude diagram (CaMD), the Gaia-2MASS-diagram from Lebzelter et al. with some alternative versions. In this way we explore the potential of these diagrams and their combination for the analysis and interpretation of datasets of LPVs. We show the possibility to classify stars into M- and C-types and to identify the mass of the bulk of the sample stars.

scholarly journals The Galactic Distribution of OH/IR Stars

1977 ◽  
Vol 42 ◽  
pp. 399-433
Author(s):  
H.J. Habing
Keyword(s):  
Present Status ◽  
Line Emission ◽  
Microwave Line ◽  
Late Type ◽  
Maser Emission ◽  
Long Period ◽  
Ir Stars ◽  
Long Period Variables ◽  
Recent Compilation ◽  
Galactic Distribution

In 1967 Wilson and Barrett (1968, 1970) discovered that some long period variables, very red and apparently very late type stars, emit OH microwave line emission that is especially strong in the 1612 MHz line at 18 cm. At present some 65 such OH-emitting stars have been identified - for a recent compilation see Bowers and Kerr (1977, M giants) and Baudry et al. (1977, M supergiants). Several stars show maser emission in H2O and SiO as well. At this colloquium Winnberg will review the present status of our knowledge of these stars.

The Galactic Distribution and Kinematics of OH Stars (A Preliminary Discussion)

1975 ◽  
Vol 2 (6) ◽  
pp. 362-363
Author(s):  
P.F. Bowers
Keyword(s):  
Large Scale ◽  
Velocity Dispersion ◽  
Neutral Hydrogen ◽  
Late Type ◽  
Velocity Range ◽  
Hydrogen Distribution ◽  
Mira Variables ◽  
Sky Survey ◽  
Ir Stars ◽  
Galactic Distribution

The majority of OH/IR stars have been identified as M-type Mira variables, but there are a few cases where the stars have been identified as M supergiants or late-type semi-regular variables. A large number of OH sources have also been discovered with the 1612 MHz OH characteristics of OH/IR stars but no apparent optical or infrared counterparts. In several cases the velocities of these unidentified sources (OH stars) have been outside the velocity range of the neutral hydrogen distribution, suggesting that some of these sources may represent a population with a higher velocity dispersion than Population I objects (Kerr and Bowers 1974a, b). The lack of infrared and optical counterparts may indicate that the sources are quite distant, since identified OH/IR stars are often bright infrared objects. A large-scale 1612 MHz sky survey has therefore been initiated to study the galactic distribution and kinematics of the OH stars and to investigate the possibility that they may represent an older population of stars (Bowers et al. 1974).

scholarly journals Revised and Updated Catalogue of the First Byurakan Survey Late-Type Stars. 2nd Edition

2018 ◽  
pp. 262-267
Author(s):  
K. S. Gigoyan ◽  
A. M. Mickaelian ◽  
G. R. Kostandyan
Keyword(s):  
Variable Stars ◽  
Sloan Digital Sky Survey ◽  
Asymptotic Giant Branch ◽  
Wide Field ◽  
Late Type ◽  
Byurakan Survey ◽  
First Byurakan Survey ◽  
Sky Survey ◽  
Search And Selection ◽  
Low Dispersion

Eighteen lists of late-type stars (LTSs) have been published between 1990 and 2016. These LTSs have been found in the low-dispersion spectroscopic plates of the First Byurakan Survey (FBS). The systematic search and selection was carried out on a surface _16000 deg2 on almost the whole area of the FBS. As a result, \Revised And Updated Catalogue Of The First Byurakan Survey Of Late-Type Stars" was generated (LTSs, _rst version). Since 2007, all FBS low-resolution spectral plates are digitized, and Digitized First Byurakan Survey (DFBS) database and second catalog of objects has been assembled. All DFBS spectral plates are analysed with the help of standard image analysis softwares (FITSView and SAO Image ds9) and numerous of comparatively faint LTSs were discovered. We present the 2nd version of the FBS catalogue of LTSs with new data. We have made cross-correlation with the Digitized First Byurakan Survey (DFBS), the United State Naval Observatory-B1.0 Catalogue, the Two Micron All-Sky Survey (2MASS), the Wide-Field Infrared Survey Explorer (new version-ALLWISE) catalogue, the Infrared Astronomical Satellite Point Source Catalogue/Faint Source Catalogue, the AKARI catalogue, the ROSAT Bright Source Catalogue/Faint Source Catalogue, the General Catalogue of Variable Stars, Sloan Digital Sky Survey (SDSS) photometric catalogue. We have added updated IMBAD data for the objects. For numerous of the new detected objects we present accurate Digitized Sky Survey 2 positions, approximate spectral subtypes refined from the DFBS low-dispersion spectra, luminosity classes estimated from 2MASS colours, and available proper motions for 1471 FBS LTSs. 2nd Version of the Revised and Updated Catalogue lists a large number of completely new objects, which promise to extend very significantly the census of M giants, faint N-type Asymptotic Giant Branch (AGB) carbon stars, CH {type carbon giants at high Galactic latitudes, also M dwarfs in the vicinity of the Sun up to 16.0-17.0 mag. in visual. We present also some important data from the Gaia DR2 data base for FBS LTSs. Some supplementary spectra obtained with the Byurakan Observatory 2.6 m telescope and LAMOST telescope are shown.

scholarly journals Monitoring active stars 29 Dra, 12 Cam and colour excess of II Peg

2007 ◽  
pp. 51-56
Author(s):  
M. Zboril
Keyword(s):  
High Latitude ◽  
Colour Index ◽  
Light Curves ◽  
Late Type ◽  
Long Period ◽  
Colour Excess ◽  
Active Stars

We present the BV light curves analysis of late-type, long-period stars 29 Dra, 12 Cam for the season 2005/2006, and shorter-period star II Peg for the same season. High latitude spots (alternatively spot configuration) cooler than surrounding photosphere were able to explain the light curves. The II Peg colour- index shift in H-R diagram is probably a consequence of stellar metallicity. Other associated mechanisms are briefly discussed.

scholarly journals The Variability of R, N, and C Stars from HIPPARCOS and AAVSO Data

2000 ◽  
Vol 177 ◽  
pp. 171-178 ◽  
Author(s):  
Michel Grenon ◽  
Janet A. Mattei ◽  
Laurent Eyer ◽  
Grant Foster
Keyword(s):  
Satellite Observations ◽  
Light Curves ◽  
Late Type ◽  
Carbon Stars ◽  
Smooth Curves ◽  
Long Period ◽  
Preliminary Discussion

Accurate photometry was obtained for all program stars during the 3.3-year HIPPARCOS mission. The final observing program included several hundred Mira (M), long-period semiregular (SR), and irregular (L) variables. A detailed calibration of the aging of the optics allowed the evaluation of very precise magnitudes over the whole range of star colors. Since the time coverage of the satellite observations was not sufficient to describe the behavior of M, SR, or L type variables, smooth curves were fitted statistically to the dense AAVSO observations. These curves were then transformed to the HIPPARCOS system in order to complement the HIPPARCOS photometry and thus produce precise light curves with fuller time coverage, for a set of several hundred late-type variables, including most carbon stars brighter than V = 12.4 at minimum luminosity. A preliminary discussion of the behavior of C stars, as observed from space in the broad Hp band, is given.

scholarly journals SuperWASP variable stars: classifying light curves using citizen science

2021 ◽  
Vol 502 (1) ◽  
pp. 1299-1311
Author(s):  
Heidi B Thiemann ◽  
Andrew J Norton ◽  
Hugh J Dickinson ◽  
Adam McMaster ◽  
Ulrich C Kolb
Keyword(s):  
Variable Stars ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Data Set ◽  
Resultant Data ◽  
Sky Survey ◽  
Short Period ◽  
Contact Binaries ◽  
Analysis Of Results

ABSTRACT We present the first analysis of results from the SuperWASP variable stars Zooniverse project, which is aiming to classify 1.6 million phase-folded light curves of candidate stellar variables observed by the SuperWASP all sky survey with periods detected in the SuperWASP periodicity catalogue. The resultant data set currently contains >1 million classifications corresponding to >500 000 object–period combinations, provided by citizen–scientist volunteers. Volunteer-classified light curves have ∼89 per cent accuracy for detached and semidetached eclipsing binaries, but only ∼9 per cent accuracy for rotationally modulated variables, based on known objects. We demonstrate that this Zooniverse project will be valuable for both population studies of individual variable types and the identification of stellar variables for follow-up. We present preliminary findings on various unique and extreme variables in this analysis, including long-period contact binaries and binaries near the short-period cut-off, and we identify 301 previously unknown binaries and pulsators. We are now in the process of developing a web portal to enable other researchers to access the outputs of the SuperWASP variable stars project.

scholarly journals Physical Parameters of Late-type Contact Binaries in the Northern Catalina Sky Survey

2020 ◽  
Vol 247 (2) ◽  
pp. 50 ◽  
Author(s):  
Weijia Sun ◽  
Xiaodian Chen ◽  
Licai Deng ◽  
Richard de Grijs
Keyword(s):  
Physical Parameters ◽  
Late Type ◽  
Sky Survey ◽  
Type Contact ◽  
Contact Binaries

scholarly journals Galaxies in Selected Fields of the Second Byurakan Survey

1999 ◽  
Vol 194 ◽  
pp. 162-167
Author(s):  
S.A. Hakopian ◽  
S.K. Balayan
Keyword(s):  
Spectral Classification ◽  
Byurakan Survey ◽  
Object Selection ◽  
Current State ◽  
Sky Survey

The current state of investigation of galaxies in seven fields of the Second Byurakan Sky Survey (SBS) is presented. These fields have been selected by the results of completeness estimation of the samples of galaxies in 65 fields.Observations of the SBS faint candidate galaxies are carried out to complete spectroscopy of galaxies in the selected fields. Currently in one SBS field, with coordinates of center α=15h30m and δ=+59°, the spectra of all galaxies have been obtained and reduced. Besides the redshift and spectral classification, these data allow estimates of the quality of object selection in the Second Byurakan Survey at faint magnitudes.

Optical Identification of the ROSAT All-Sky Survey Sources in Two 2° × 2° Fields

1997 ◽  
Vol 159 ◽  
pp. 427-428
Author(s):  
Y. Zhao ◽  
J. Zhong ◽  
J. Wei ◽  
J. Hu ◽  
Q. Li
Keyword(s):  
Ccd Camera ◽  
Seyfert Galaxies ◽  
Astronomical Observatory ◽  
Active Galaxies ◽  
Clusters Of Galaxies ◽  
Late Type ◽  
Optical Identification ◽  
X Ray ◽  
Sky Survey

AbstractWe used the CCD camera and spectrograph of the 2.16-m telescope of Beijing Astronomical Observatory to identify the ROSAT All-Sky survey sources in two 2° Ü 2° fields. Of a total of 16 X-ray sources, we identified 13 of them as follows: two QSOs, two Seyfert galaxies, two active galaxies, two clusters of galaxies, and five late-type stars. Three X-ray sources remained unidentified.

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