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General Catalog of Variable Stars (GCVS database, Version 2013 Apr.)

Samus N.N., Durlevich O.V., Kazarovets E V., Kireeva N.N., Pastukhova E.N., Zharova A.V., et al.

Institute of Astronomy of Russian Academy of Sciences and Sternberg State Astronomical Institute of the Moscow State University

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INTRODUCTION

The present improved electronic version of the GCVS4 Volumes I-V, combined with Name-Lists of Variable Stars Nos.67-80, are available from Sternberg Institute to http://www.sai.msu.su/gcvs/gcvs/

The information at this site is regularly updated (corrections of detected mistakes, improvements of identifications and coordinates, etc.).

This GCVS edition contains data for 28484 individual variable objects discovered and named as variable stars by 1982 and located mainly in the Milky Way galaxy. These data are contained in the first three published volumes. The computer version GCVS4 vols. I-III contains principally the same data as in the first three volumes of the printed catalog. The Name-lists Nos. 67-80 contain variable stars designated between 1982 and 2013; these stars are also incorporated in the combined catalog. The fourth volume of the fourth edition, published in 1990, contains a table of all variables ordered by right ascension (B1950), a table of variables listed by variability type, and an extensive series of cross-identification tables to alternative designations. The electronic version vol. IV contains only the cross- identification tables. The final, fifth volume contains data for variables in external galaxies (including the Magellanic Clouds) and for extragalactic supernovae.

This data set is the combined computer-readable version of the GCVS4 with improved coordinates Vols. I-III (Kholopov et al. 1985-1988) and Name-Lists of Variable Stars Nos.67-80 published in the system introduced during the preparation of the 4th GCVS edition. The total number of designated variable stars has now reached 47 811.

All variables in the present data set are arranged in the order of their names inside constellations. For Name-list stars, the information follows the format of the Name-Lists, that is, it includes only coordinates, the variability type, the range of brightness variations, and references.

For 47619 variable stars, our version provides new equatorial J2000.0 coordinates (right ascensions to within 0.01s and declinations to within 0.1"), for 21384 stars with allowance for their proper motions (vol_pos.dat).

We have corrected the errors revealed in the printed Volumes I-III. Then, we have improved coordinates for those variables of Vols. I-III which also enter Volume V, using the results of the positional determinations undertaken during the preparation of Vol. V.

We have started preparation of an electronic release GCVS 4.2 which will contain improved light elements, classifications etc. along with sufficiently accurate positional information. The first approach to this project has resulted in improved equatorial positions (B1950, J2000) for all named variable stars, with a new standard of positional accuracy, to 1 second of arc.

File Summary:
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 FileName        Explanations
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html/index.htm   HTML-site
iii.dat          The GCVS4 Catalog
vol_pos.dat      Positional information
vartype.txt      GCVS Variability Types
ref.txt          References
ref_abr.txt      The list of the abbreviations in the references
remark.txt       Remarks
constel.dat      Numerical Codes for Constellations
variable.dat     Numerical Codes for Variable stars
abbrev.txt       The catalog abbreviations

crossid.dat      The Cross-Identifications of Variable Stars

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Note on Component:

designations of components of double/multiple stars: A,B; 1,2,3 ... (tau 1). Usually only one component of the binary is variable, but there exist two cases (CE Cas A,B; EQ Peg A,B) when both components are variable and enter the catalogue as separate lines.

Note on GCVS:

traditional transliterations of greek letters are used. Lower- and upper-case latin letters must be distinguished (e.g. u Her and U Her).

Note on RAh, RAm, RAs, DE-, DEd, DEm, DEs:

the position is not listed when the variable is equivalent to another catalogued variable ("=" in column Exists, byte 150).

Note on u_DEs:

(:)a flag indicating that the coordinates are actually rougher than the accuracy standard adopted in the this table.

Note on n_magMax, n_magMin: Code for alternative photometric system.

Field is non-blank if magMin is a magnitude or amplitude given in a system other than that indicated by magCode. An asterisk in the corresponding position means the amplitude measured in white light.

Note on magCode:

the photometric system in which magMin and magMax are reported (see also Note on n_magMax, n_magMin). The main codes are P (photographic magnitudes) and V (visual, photovisual, or Johnson's V). Several stars from the 68th Name-List have in these positions "1." designating the 1.04 micrometer band of the system introduced by G.W.Lockwood. The designations u,v,b,y refer to the Stroemgren system. The symbols "Ic" and "Rc" mean magnitudes in Cousins' I system. "g" designates magnitudes in the system of Thuan and Gunn; "T" stands for broad-band Tycho magnitudes formed from B and V measurements; "r" are red magnitudes not tied to a particular system.

Note on Epoch:

Epochs are given for minimum light for all eclipsing and ellipsoidal variables, as well as for RV Tau and RS CVn types, and for maximum for all other types. This rule may occasionally be broken, but this is explained only in the remarks to the catalog, which are not available in machine-readable form at this time. The epochs are Julian dates, with the starting figures 24... omitted; The only exception is WY Sge, where the complete epoch is JD 237249:. The codes ":" are used if the epoch is uncertain.

Note on q_Epoch:

the following codes are used (see also note on Epoch) :
":" are used if the epoch is uncertain;
"+" epoch may be later than that reported;
"-" epoch may be earlier than that reported.

Note on l_Period: the following codes are used:

">" or"<" if period is a lower or upper limit, respectively.
"(": the period is the mean cycle time of a U Gem or recurrent nova (in this case, there is ")" in pos. 125).

Note on n_Period:

the following codes are used: "*N" if the period may be a multiple of the quoted value;
"/N" if the period may be a fraction of the quoted value;
")" - see the note on l_Period.

Note on M-m/D:

this column holds the rising time (M-m) of intrinsic variables, or the duration of the eclipse (D) for eclipsing binaries. These values help to define the shape of the light curve. The value is given in percentage of the period of the star.

Note on u_M-m/D:

the "*" indicates that the duration of the light constancy phase at minimum light (d) for an eclipsing variable is equal to zero.

Note on Ref1, Ref2:

"00001" - if the main characteristics of the star were determined by the authors themselves.
"00002" - "09148" - Vol. I GCVS (see Kholopov et al., 1985-1988).
"09149" - "09558" - Vol. II GCVS
"09559" - "10200" - Vol. III GCVS
"V 001" - "V 554" - Vol. V GCVS
"67001" - "79333 - Name-Lists Nos.67-78
" HIP" - The Special Name-List No.74 for Hipparcos Variables.
If no chart is available for the variable, but the star is contained in one of the Durchmusterung catalogs or the Hubble Space Telescope Guide Star Catalog, the corresponding abbreviation (BD, CPD, CoD, GSC, HIP) is given.

Note on Exists:

"N" in byte 164 if the star does not exist.
"=" in byte 164 appears in three cases.

First, it is used if the variable is equivalent to another cataloged variable. In such case, after the "=" symbol, the alternative name of the variable follows, and all necessary information on the star is to be found under that alternative name.

Second, it is used for all variables of the Name-Lists Nos.67-78, it is followed by the two-digit number of the Name-list and the four-digit number of the star in the Name-list, and the information for the star follows the format of the Name-lists (see above).

Third, the "=" symbol may be followed by the star's name in the GCVS Vol. V (where the explanation of the designations is also given). This means that the star enters also Vol. V, and the information of Vol. V makes it possible to improve the data of Vols. I-III. In this case, the symbol "*" in column 178 means the presence of remarks in Vol. V.

The table vol_pos.dat provides positional information based on our identifications with major astrometric catalogs, on published data, or on our new measurements (see below) for 47619 stars of the new version of GCVS (including stars of the new name lists).

The order of stars in this table is the same as that in the main table.

Byte-by-byte Description of file: vol_pos.dat

POSITION ACCURACY FLAG (:) - indicating that the coordinates are actually rougher than the new accuracy standard adopted in the catalog, because we failed to determine better coordinates and to find them in source catalogs or in publications. In comparatively numerous cases, such coordinates were obtained by transforming B1950.0 coordinates from the IRAS Point Sorce Catalog (see below).

EPOCH of the given coordinates. No epoch is provided when using the coordinates from the literature if the epoch was no specified in the publication and cold not be established;

FLAG (?) ON IDENTIFICATION - the variable star's identification with the source catalog is uncertain;

THE SOURCE OF ASTROMETRIC DATA - A brief designation of the source of astrometric data. In several cases, the catalog designation is folowed by the symbol "+pm"; it implies that the position for a certain epoch was taken from the catalog and reduced to the epoch 2000.0 using information on the star's proper motion from a different source.

Below, we give a list of the major catalogs and other data sources used, roghly in the order of our preference in identifying variable stars (see also the description of the catalogs provided for A.A. Volchkov's visualization code we used at www.simfov.ru).

Hip - The Hipparcos Catalogue (ESA 1997).

Tyc2 - The Tycho Catalogue (Hog et al. 2000). In isolated instances where the star is absent in the second Tycho catalogue but is present in the first catalogue (ESA 1997), the source is indicated as Tyc1.

UCAC2 - US Naval Observatory CCD Astrograph Catalog (Zacharias et al., 2004).

PPM - The Positions and Proper Motions (Roser et al. 1991-1993).

NPM - The Lick Northern Proper Motion Program (Klemola et al. 1987).

AC - The Four-Million Star Catalog (see Gulyaev and Nesterov 1992).

ACT - The ACT Reference Catalog (Urban et al. 1997).

GSC 2.2 - The Guide Star Catalog, Version 2.2.01, 2001, Space Telescope Science, Institute and Osservatorio Astronomico di Torino.

GSC - The Guide Star Catalog (Lasker et al. 1990). The symbol "ns" accompanying a GSC reference implies that the entry is marked as a nonstellar object in the cited catalog.

A2.0, B1.0 - A Catalog of Astrometric Standards (Monet et al., 1998) (there were rare cases when the star could be found only in the previous version of the catalogue, marked as A1.0); The Whole-Sky USNO-B1.0 Catalog of 1 045 913 669 Sources (Monet et al., 2003).

2MASS - The Two Micron All Sky Survey (Cutri et al., 2003).

GCVS - For some 10 stars, the coordinates were measured by the authors using Digitized Sky Survey images, plates from different collections, or other images.

Lit. - The coordinates taken from current astronomical periodicals.

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N.N. Samus    (Moscow Inst. Astron.),        O.V. Durlevich   (Sternberg Astron. Inst., Moscow)  16-Feb.-2008

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