首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
We present a new electronic version of the first volume of the General Catalogue of Variable Stars (GCVS), fourth edition, which contains data on 10558 variable stars in Andromeda-Crux (the constellations are ordered in the Catalog according to the Latin alphabet). This version incorporates the name lists of variable stars from no. 67 to no. 76 for the same constellations. The main distinctive feature of the new version is that it provides improved equatorial J2000.0 coordinates for 10349 stars (including those for 4587 stars corrected for proper motions). These are based on identifications with positional catalogs using finding charts and on our new measurements. We searched for a number of stars on original plates from the plate collections of several observatories. The version also includes a file of remarks to the first GCVS volume and a preliminary version of the file of bibliographic references to the entire fourth edition of the GCVS. Apart from a complete update of the positional information, the new version incorporates all the other corrections that were found to be necessary after the first GCVS volume was published (1985).  相似文献   

2.
We present a new electronic version of the second volume of the fourth edition of the General Catalogue of Variable Stars (GCVS), which contains data on 13480 variable stars in the constellations Cygnus-Orion (the order of constellations in the Catalogue follows the Latin alphabet). The new version takes into account the Name Lists of Variable Stars from no. 67 to 76 for the same constellations. The main distinctive feature of the new version is that it contains improved equatorial J2000.0 coordinates for 13446 stars (including those for 5052 stars with an allowance made for proper motions), based on the identifications with positional catalogs using finding charts, as well as on our new measurements. We searched for a number of stars on original plates from the collections of several observatories and using digital sky survey images. The new version also includes a file of remarks to the second and third GCVS volumes. Apart from a complete update of the positional information, we took into account several corrections that were found to be necessary after the publication of the second GCVS volume (1985). We present a list of references to new Internet resources.  相似文献   

3.
We present a new electronic version of the third volume of the fourth edition of the General Catalogue of Variable Stars (GCVS) that contains data on 13 855 variables in the constellations Pavo-Vulpecula. The Name Lists of Variable Stars from no. 67 to no. 77 were included in the new version. The main distinctive feature of the new version is that improved J2000.0 equatorial coordinates (including those for 6163 stars corrected for the proper motions) based on the identifications with positional catalogues using finding charts and on our new measurements are presented for 13 812 stars. We searched for a number of stars on original plates from the plate stacks of several observatories and using images from digital sky surveys. Apart from the complete update of the positional information, we made several corrections that were found to be necessary after the publication of the GCVS Volume III (1985) and several corrections of the information about the variability features based on photometry from currently available automatic sky surveys. A number of problem identifications are described in detail. The new version completes our long-term work on the complete revision of the positional information in the GCVS. In the Conclusions, we give a list of references to new Internet resources.  相似文献   

4.
We present the database of maser sources in H2 O, OH and Si O lines that can be used to identify and study variable stars at evolved stages. Detecting the maser emission in H2 O, OH and Si O molecules toward infrared-excess objects is one of the methods for identifing long-period variables(LPVs, including miras and semiregulars), because these stars exhibit maser activity in their circumstellar shells. Our sample contains 1803 known LPV objects. Forty-six percent of these stars(832 objects) manifest maser emission in the line of at least one molecule: H2 O, OH or Si O. We use the database of circumstellar masers in order to search for LPVs which are not included in the General Catalogue of Variable Stars(GCVS). Our database contains 4806 objects(3866 objects without associations in GCVS) with maser detection in at least one molecule. Therefore it is possible to use the database in order to locate and study the large sample of LPV stars. The database can be accessed at http://maserdb.net.  相似文献   

5.
We present a new unbiased search and analysis of all B stars in the solar neighbourhood (within a volume of 400 pc diameter) using the Arivel data base to track down the remains of the OB associations, which hosted the supernovae (SNe) responsible for the Local Bubble (LB) in the interstellar gas. We find after careful dereddening and by comparison with theoretical isochrones, that besides the Upper Scorpius the Upper Centaurus Lupus and Lower Centaurus Crux subgroups are the youngest stellar associations in the solar neighbourhood with ages of 20–30 Myr, in agreement with previous work. In search for the 'smoking gun' of the origin of the LB, we have traced the paths of the associations back into the past and found that they entered the present bubble region 10–15 Myr ago. We argue that the LB began to form then and estimate that 14–20 SNe have gone off since. It is shown that the implied energy input is sufficient to excavate a bubble of the presently observed size.  相似文献   

6.
We present the results of our search for the stars kinematically related to the young star HD 166191 surrounded by a warm dust disk. Using data from the GAIA DR1, 2RXS, ALLWISE catalogues and confirming optical spectroscopy, we have identified five stars of age ~10 Myr with similar kinematics in a sky region of radius ~11° on the periphery of the Scorpius–Centaurus OB association. Simulations of their orbits into the past show that the HD 166191 group stars were not formed inside or on the nearest periphery of the Scorpius–Centaurus association and do not belong to the young kinematic groups known in its neighborhoods either. The age and motion of the HD 166191 group in the Galaxy are closest to those of the extended Corona Australis association (ext.CrA). Possible scenarios for the formation of these young associations are discussed.  相似文献   

7.
The aim of this project is to study the spatial distribution of contact binaries and to compare the sample from the project of study the W UMa-type stars, with existing databases such as Hipparcos, GCVS or ASAS (ESA, 1997; GCVS, 2005; Pojmanski, 2002).  相似文献   

8.
The results from a flare star investigation in the open cluster Alpha Persei are presented. Photographic flare star monitoring and CCD photometry of the discovered 4 new flare stars are made. The flare star activity phenomenon is restricted to the classical flare stars (UV Ceti type) as classified in the GCVS. The V/V‐I diagramme of the members of the cluster with the locations of the considered flare stars is given. Most of the flare stars are probable cluster members. The flare frequency determined from the Rozhen flare star monitoring is very low–one flare event occurs for 38.5 hours effective observing time. Comparison with the flare activity of the Pleiades is made because of the small difference in the age and distance of the clusters.  相似文献   

9.
Eclipsing variables in visual binary and multiple stars are searched using data from GCVS, WDS, and CCDM catalogs. The list of 421 eclipsing variables is obtained. The masses of components of multiple systems from the list are estimated using the mass-luminosity relation for the main sequence stars. It is shown that, for 85% multiple systems from the list, the mass of visual components is smaller by a factor of 2 than the total mass of close binary systems. The distributions of orbital elements of visual binary systems are constructed and used for calculation of orbit semi-major axes for star from the list. The distributions of orbit semi-major axes and periods obtained from observations are approximated by Gaussian curves. The maxima of the curves correspond to a = 800 a.u. and P = 7600 years, respectively. The distribution of orbit semi-major axes larger than 800 a.u. is better described by Opik’s law; it is expected that this law describes the real a distribution in the region of small values as well. The frequency of eclipsing variables in multiple stars makes 12% of the total number of stars of this type in GCVS.  相似文献   

10.
The observeduvby and Hα indices of member stars of the Hyades and Praesepe clusters have been analysed in detail for rotation effects. The Alpha Persei, Pleiades and the Centaurus subgroup of the Scorpio—Centaurus association have been reanalysed using the observed indices instead of the extinction-corrected indices used earlier. The observed rotation effects from the analysis of these cluster data are found to be in excellent agreement with the theoretical predictions of Collins & Sonneborn (1977). We have also analysed the α,c and (u − b) values of the member stars of NGC 1976, 2264, 2287, 2422, 4755,1C 2391, IC 2602 and IC 4665 for rotation effects. The results are found to be consistent with the theoretical predictions. The observed slopes of the rotation effects were used to determine the zero rotation main sequence values of the intermediate band photometric indices for selected clusters. We also corrected the observed indices for each star in each cluster using the theoretical predictions of Collins and Sonneborn and derived the ZRMS values for each cluster. The agreement between the two determinations is found to be good. The various ZRMS curves were utilised to derive the ZRZAMS values. A preliminary calibration of the absolute visual magnitudes as a function of α valid for ZRZAMS has also been derived. The ZRMS values of the intermediate band photometric indices for different clusters and the ZRZAMS values are listed as a function of α. on leave from Assumption College, Changanacherry, Kerala.  相似文献   

11.
A search for RR Lyrae stars has been conducted in the publicly available data of the Northern Sky Variability Survey. Candidates have been selected by the statistical properties of their variation; the standard deviation, skewness and kurtosis with appropriate limits determined from a sample 314 known RRab and RRc stars listed in the General Catalogue of Variable Stars. From the period analysis and light-curve shape of over 3000 candidates 785 RR Lyrae have been identified of which 188 are previously unknown. The light curves were examined for the Blazhko effect and several new stars showing this were found. Six double-mode RR Lyrae stars were also found of which two are new discoveries. Some previously known variables have been reclassified as RR Lyrae stars and similarly some RR Lyrae stars have been found to be other types of variable, or not variable at all.  相似文献   

12.
The variable star V1129 Cen is classified in the GCVS as being of β Lyr type. Unusual for such stars, it exhibits outbursts roughly once a year, lasting for ∼ 40 days. For this reason, a relationship to the dwarf novae has been suspected. Here, for the first time a detailed analysis of the light curve of the system is presented. Based on observations with high time resolution obtained at the Observatório do Pico dos Dias and on the long term ASAS light curve the orbital variations of the system are studied. They are dominated by ellipsoidal variations and partial eclipses of a probably slightly evolved F2 star in a binary with an orbital period of 21h 26m. Comparison with the characteristics of dwarf novae show that the observational properties of V1129 Cen can be explained if it is just another dwarf novae, albeit with an unusually bright and early type mass donor which outshines the accretion disk and the mass gainer to a degree that many normal photometric and spectroscopic hallmarks of cataclysmic variables remain undetected.  相似文献   

13.
A selection criterion based on the relative strength of the largest peaks in the amplitude spectra, and an information criterion are used in combination to search for multiperiodicities in Hipparcos epoch photometry. The method is applied to all stars which have been classified as variable in the Hipparcos catalogue: periodic, unsolved and microvariables. Results are assessed critically: although there are many problems arising from aliasing, there are also a number of interesting frequency combinations which deserve further investigation. One such result is the possible occurrence of multiple periods of the order of a day in a few early A-type stars. The Hipparcos catalogue also contains a number of these stars with single periodicities: such stars with no obvious variability classifications are listed, and information about their properties (e.g., radial velocity variations) discussed. These stars may constitute a new class of pulsators.  相似文献   

14.
We present a new catalogue of variable stars compiled from the data taken for the University of New South Wales Extrasolar Planet Search. From 2004 October to 2007 May, 25 target fields were each observed for one to four months, resulting in ∼87 000 high-precision light curves with 1600–4400 data points. We have extracted a total of 850 variable light curves, 659 of which do not have a counterpart in the General Catalogue of Variable Stars, the New Suspected Variables catalogue or the All Sky Automated Survey southern variable star catalogue. The catalogue is detailed here, and includes 142 Algol-type eclipsing binaries, 23 β Lyrae-type eclipsing binaries, 218 contact eclipsing binaries, 53 RR Lyrae stars, 26 Cepheid stars, 13 rotationally variable active stars, 153 uncategorized pulsating stars with periods <10 d, including δ Scuti stars, and 222 long period variables with variability on time-scales of >10 d. As a general application of variable stars discovered by extrasolar planet transit search projects, we discuss several astrophysical problems which could benefit from carefully selected samples of bright variables. These include (i) the quest for contact binaries with the smallest mass ratio, which could be used to test theories of binary mergers; (ii) detached eclipsing binaries with pre-main-sequence components, which are important test objects for calibrating stellar evolutionary models and (iii) RR Lyrae-type pulsating stars exhibiting the Blazhko effect, which is one of the last great mysteries of pulsating star research.  相似文献   

15.
We look for high‐amplitude variable young stars in the open clusters and associations of the Orion Belt. We use public data from the ASAS‐3 Photometric V ‐band Catalogue of the All Sky Automated Survey, infrared photometry from the 2MASS and IRAS catalogues, proper motions, and the Aladin sky atlas to obtain a list of the most variable stars in a survey area of side 5° centred on the bright star Alnilam (ε Ori) in the centre of the Orion Belt. We identify 32 highly variable stars, of which 16 had not been reported to vary before. They are mostly variable young stars and candidates (16) and background giants (8), but there are also field cataclysmic variables, contact binaries, and eclipsing binary candidates. Of the young stars, which typically are active Herbig Ae/Be and T Tauri stars with Hα emission and infrared flux excess, we discover four new variables and confirm the variability status of another two. Some of them belong to the well known σ Orionis cluster. Besides, six of the eight giants are new variables, and three are new periodic variables (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

16.
The Binary star DataBase(BDB, http://bdb.inasan.ru) combines data from catalogs of binary and multiple stars of all observational types. There is a number of ways for variable stars to form or to be a part of binary or multiple systems. We describe how such stars are represented in the database.  相似文献   

17.
We report the results of a search for variable stars in the open cluster NGC 2141. Ten variable stars are detected, among which nine are new variable stars and they are classified as three short-period W UMa-type eclipsing binaries, two EAtype eclipsing binaries, one EB-type eclipsing binary, one very short-period RS CVntype eclipsing binary, one d-type RR Lyrae variable star, and one unknown type of variable star. The membership and physical properties are discussed, based on their light curves, positions in the color magnitude diagrams, spatial locations and periods.A known EB-type eclipsing binary is also identified as a blue straggler candidate in the cluster. Furthermore, we find that all eclipsing contact binaries have prominent asymmetric eclipses and display the O'Connell effect, which increases with a decrease in orbital periods. This suggests that the O'Connell effect is probably related to the evolution of the orbital period in short period eclipsing binary systems.  相似文献   

18.
An ongoing SAO RAS program for the 6-m telescope to search for and study luminous blue variable (LBV) candidates in the M31 and M33 galaxies was started in 1997. This paper summarizes the results of our observations over the last 20 years. Over this time, we have a general lists of candidates and obtained photometry and spectroscopy for approximately one hundred stars from the list. A detailed study and classification of LBV candidates were carried out.We alsomonitored spectrally and photometrically the confirmed LBV stars in these galaxies. Based on these results, the spectral energy distributions (SEDs) of LBVs and LBV candidates were computed, and the interstellar extinction values, temperature, and luminosity were derived. We propose a new method of confirming the nature of LBV stars. It is based on a special property exhibited only by LBV stars—the constancy of the bolometric luminosity, with except of a rare phase of giant eruption, registered for two historical LBVs in our galaxy and about few dozen extragalactic LBVs. Using this method, we determine the fundamental parameters of these stars: temperature, radius, luminosity, and interstellar extinction. We discuss the nature of several individual LBV stars discovered by us in M33 and the classification of the LBV candidates in M31. Thus, for 20 years of observations we have found four LBV stars in M33; in the M31 galaxy with different methods, we have confirmed seven objects as a LBV class.  相似文献   

19.
Anharmonic oscillations of rotating stars have been studied by various authors in literature to explain the observed features of certain variable stars. However, there is no study available in literature that has discussed the combined effect of rotation and tidal distortions on the anharmonic oscillations of stars. In this paper, we have created a model to determine the effect of rotation and tidal distortions on the anharmonic radial oscillations associated with various polytropic models of pulsating variable stars. For this study we have used the theory of Rosseland to obtain the anharmonic pulsation equation for rotationally and tidally distorted polytropic models of pulsating variable stars. The main objective of this study is to investigate the effect of rotation and tidal distortions on the shapes of the radial velocity curves for rotationally and tidally distorted polytropic models of pulsating variable stars. The results of the present study show that the rotational effects cause more deviations in the shapes of radial velocity curves of pulsating variable stars as compared to tidal effects.  相似文献   

20.
First BV measures of the short period variable UU Cam are presented here. Though the GCVS classification of the star as an RR Lyr variable, based on the spectrographic measures of Bond (1978), is substantially confirmed, there remains some doubts about it, as suggested by the general aspect of theB-V colour index.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号