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GCVS - General Catalog of Variable Stars, March 2012 Version

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Overview

The General Catalog of Variable Stars (GCVS) is the only reference source on all known variable stars. This database table is based on the electronically-readable version as distributed by the Sternberg Astronomical Institute and Institute of Astronomy (Russian Acad. Sci.), Moscow. It is the catalog of variable stars, updated and completed with the Name-Lists of Variables Stars Nos. 67-79.

The total number of designated variable stars has now reached 45835. Errors detected in the printed Volumes I-III and in the Name-Lists have been corrected.

There are 157 stars for which no positions are listed as they are now considered to be duplicates of other stars in the GCVS.

The present improved electronic version of the GCVS 4th Edition, Volumes I-V, combined with the Name-Lists of Variable Stars Nos. 67 - 79, is also available from the Sternberg Institute of Moscow University via at ftp://ftp.sai.msu.su/pub/groups/cluster/gcvs/gcvs/ or http://www.sai.msu.su/gcvs/gcvs/.


Catalog Bibcode

<B/gcvs/>

References

General Catalog of Variable Stars (GCVS database, Version 2012Apr)
     Samus N.N., Durlevich O.V., et al.
    <Institute of Astronomy of Russian Academy of Sciences and Sternberg
     State Astronomical Institute of the Moscow State University >

Provenance

This online version of the GCVS Catalog was updated by the HEASARC in December 2012, based on CDS Catalog B/gcvs, table gcvs_cat.dat. The latter was itself based on an electronically-readable version that was distributed by the Sternberg Astronomical Institute and Institute of Astronomy (Russian Acad. Sci.), Moscow.

HEASARC Changes

The HEASARC has made a small number of mostly cosmetic changes to this catalog. Firstly, variable star names for the 335th to 999th variables in a constellation have had the zero following the 'V' character deleted, e.g., V335 And rather than V0335 And, to conform with the standard naming convention. Secondly, a number of the parameters that are flags had values of '*' in the original catalog; the HEASARC in some cases has changed these values to other symbols because an asterisk is a wild-card character in its database systems. Thirdly, the original values of the position_flag parameter of ":" "*" and "'" have been changed to A B and C, respectively, in this HEASARC version. Fourthly, the original values of the period_note parameter of *2, *N, and /N) have been changed to M2, MN, and FN, respectively, in this HEASARC version. Fifthly, the HEASARC has added two parameters, epoch_precision and period_precision, that give the number of decimal places to which the corresponding epoch and period parameters were given in the original table, e.g., if an entry has period_precision = 7, then its period was given to a precision of 10-7 days. Finally, the original value of '*' for the position_note parameter has been changed to 'Y' in the HEASARC version of this catalog.

Parameters

Variable_Star_Number
The GCVS numeric designation of the variable star, made from the constellation and star names codes. The numeric code for the constellation name is in alphabetic order of the full constellation name, so, for example, Cancer or CNC has a code value of 12 which precedes the code value of 16 for Capricornus or CAP). The codes are as follows:

  Constellation   Constell_code    Constellation   Constell_code
      Name                             Name

      And         1                    Ant         2
      Aps         3                    Aqr         4
      Aql         5                    Ara         6
      Ari         7                    Aur         8
      Boo         9                    Cae        10
      Cam        11                    Cnc        12
      CVn        13                    CMa        14
      CMi        15                    Cap        16
      Car        17                    Cas        18
      Cen        19                    Cep        20
      Cet        21                    Cha        22
      Cir        23                    Col        24
      Com        25                    CrA        26
      CrB        27                    Crv        28
      Crt        29                    Cru        30
      Cyg        31                    Del        32
      Dor        33                    Dra        34
      Equ        35                    Eri        36
      For        37                    Gem        38
      Gru        39                    Her        40
      Hor        41                    Hya        42
      Hyi        43                    Ind        44
      Lac        45                    Leo        46
      LMi        47                    Lep        48
      Lib        49                    Lup        50
      Lyn        51                    Lyr        52
      Men        53                    Mic        54
      Mon        55                    Mus        56
      Nor        57                    Oct        58
      Oph        59                    Ori        60
      Pav        61                    Peg        62
      Per        63                    Phe        64
      Pic        65                    Psc        66
      PsA        67                    Pup        68
      Pyx        69                    Ret        70
      Sge        71                    Sgr        72
      Sco        73                    Scl        74
      Sct        75                    Ser        76
      Sex        77                    Tau        78
      Tel        79                    Tri        80
      TrA        81                    Tuc        82
      UMa        83                    UMi        84
      Vel        85                    Vir        86
      Vol        87                    Vul        88
  
The star number within the constellation, which typically corresponds to the order in which the variables were found. For historical reasons, the first designated variable star in a constellation was given the name 'R constellation', e.g., 'R CMa', the second the prefix 'S', etc, the ninth 'Z', the tenth 'RR', etc., the 55th 'AA', etc, until the 334th 'QZ', at which point the letters have been exhausted, and the 335th variable is given the 'V0335' (or V335) prefix, e.g., 'V0335 And', and so on for all subsequent discoveries in the constellation.

Variable_Star_Cpt
The component identification, 'A', 'B', etc., i.e., the designations of components of double/multiple stars. Usually, only one component of the binary is variable, but there are 2 cases (CE Cas A and B, and EQ Peg A and B) where both components are variable and are listed as separate entries in the catalog.

Name
The variable star designation. For a brief explanation of the variable star naming convention, see the help entry for the variable_star_number parameter. Notice that stars which have Bayer designations, e.g. Alpha Ori, which have been discovered to be variable stars have not been given a new variable star designation but are listed by their Bayer designation in the GCVS, e.g., as 'alf Ori'. (The traditional transliterations of Greek letters are used, e.g., 'alf' for alpha). There are also a small number of historical variable stars which were named using lower-case latin characters, e.g. g Her and u Her. The lower- and upper-case latin letters must be distinguished, notice, because in some cases, e.g., u Her and U Her, there are names for completely different stars using the alternate naming conventions.

Note_Flag
This flag is set to 'Y' if there are notes on this star in the published version of the catalog: these comments can be found in ftp://cdsarc.u-strasbg.fr/cats/B/gcvs/gcvs_rem.dat.

RA
The Right Ascension of the star in the specified equinox. This was given to no better than a precision of 0.1 seconds of time in the originating table.

Dec
The Declination of the star in the specified equinox. This was given to a precision of 1 arcsecond in the originating table.

LII
The Galactic Longitude of the star.

BII
The Galactic Latitude of the star.

Position_Flag
This is a code flag describing the positional accuracy, as follows:

    ':'  means the position is uncertain
    'Y'  means that the coordinates could not be improved and that they
         were recalculated from old coordinates to the J2000.0 equinox
         with allowance for precession
  

Variability_Type
The type of variability according to the GCVS variability classification scheme. The system of variable star classification corresponds to the GCVS, 4th edition, with six additional classes (ZZO, AM, R, BE, LBV, and BLBOO) that were introduced in the Name-Lists 67 - 72 and in the GCVS vol. V. The full scheme is described in the file: ftp://cdsarc.u-strasbg.fr/cats/B/gcvs/vartype.txt. The HEASARC has made one change to the schema therein described: unique variable stars outside of the range of the GCVS classification scheme are designated as 'Unique', rather than by '*' as in the reference, so as to avoid confusion with the wild-card asterisk character.

Limit_Max_Mag
This parameter is a limit [<>] or amplitude flag [(] for the maximum magnitude, where '>' indicates that the latter is a faint limit, '<' that it is a bright limit, and '(' that it is an amplitude rather than an observed magnitude.

Max_Mag
The apparent magnitude at maximum brightness, or, if the value of limit_max_mag is '(', the amplitude of variation.

Max_Mag_Flag
This flag is set to ':' if the maximum magnitude is considered uncertain.

Limit_Min_Mag
This is a limit flag for the minimum magnitude, '>' indicating that the latter is a bright limit., and '(' that it is an amplitude rather than an observed magnitude.

Min_Mag
This parameter is either the apparent magnitude at minimum brightness, or, if the value of limit_min_mag is '(', the amplitude of variation.

Min_Mag_Flag
This flag is set to ':' if the minimum magnitude is considered uncertain.

Min_Mag_Alt_Sys
This is a code which is non-blank when the minimum magnitude or amplitude (min_mag) is given in an alternative photometric system to the one for the maximum magnitude (max_mag) which is given by the mag_system parameter. These codes are described in the parameter help for the mag_system parameter.

Mag_System
The photometric system in which the maximum and minimum (unless min_mag_altsys is non-blank) magnitudes are reported. The main codes used are p (photographic magnitudes) and V (visual, photovisual, or Johnson V). Several stars from the 68th Name-List have values of '1.' designating the 1.04 micrometer band of the system introduced by G.W. Lockwood. The designations u, v, b, and y refer to the Stroemgren system, the symbols 'Ic'and 'Rc' mean magnitudes in Cousins' RI system, 'g' designates magnitudes in the system of Thuan and Gunn, 'T' stands for broad-band Tycho magnitudes formed from B and V measurements, while 'r' indicates red magnitudes that are not tied to a particular system. Observations made in 'white light' are indicated by 'w' (rather than '*' as in the original table).

Epoch
This is generally the epoch for maximum light, in Julian Days, except for all eclipsing and ellipsoidal variables, as well as for RV Tau and RS CVn types, where it is the epoch for minimum light. This rule may occasionally be broken, but this is explained only in the remarks to the catalog.

Epoch_Precision
The precision of the quoted epoch value, i.e., the number of digits after the decimal point in the original table. Thus, a precision of 4 means that the epoch was given to 10-4 days in the original table.

Epoch_Flag
This parameter is a flag qualifying the epoch according to the following codes:

  ':'   epoch is uncertain;
  '+'   epoch may be later than that reported;
  '-'   epoch may be earlier than that reported.
  

Nova_Year
The year of outburst for a nova or supernova. The exact date of maximum light is given in JD in the epoch parameter.

Nova_Year_Flag
This parameter is set to ':' to indicate that there is uncertainty in the year of the nova or supernova outburst.

Limit_Period
A code qualifying the period, as follows: '>' or '<' if the period is a lower or upper limit, respectively, or '(' if the period is the mean cycle time of a U Gem or recurrent nova.

Period
The period of the variable star, in days. This is given with a range of precisions up to a possible maximum of 1.E-10 days in the original table.

Period_Precision
The precision of the quoted period value, i.e., the number of digits after the decimal point in the original table. Thus, a precision of 4 means that the period was given to 10-4 days in the original table.

Period_Note
This is another flag that contains information if the actual period may be either a multiple ('MN' or 'M2') or a fraction ('FN') of the quoted period value.

Rise_Eclipse_Time
This parameter contains either the rise time (M-m) for 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 as a percentage of the period of the star.

Rise_Eclipse_Time_Flag
This flag is set to ':' if the rise time or eclipse duration given in the rise_eclipse_time parameter is considered uncertain.

Eclipse_Var_Note
This is a note used for eclipsing variables that is set to '0' when the duration of the light constancy phase at minimum light (d) is equal to zero, or to ':' if the value is considered uncertain.

Spect_Type
The spectral type of the variable star.

Ref_Star
This is a reference code referring to a major study of the star, as follows: (the codes and their corresponding references can be found in ftp://cdsarc.u-strasbg.fr/pub/cats/B/gcvs/refs.dat)

  "00002" - "09148" -  Vol.  I  GCVS  (see Kholopov et al., 1985-1988)
  "09149" - "09558" -  Vol. II  GCVS
  "09559" - "10200" -  Vol. III GCVS
  "67001" - "77229" -  Name-Lists Nos.67-77
  
References from Vol. V (extragalactic variables) start with the letter 'V', and references to the suspected variables start with 'N' (first part) or 'S' (supplement). References may also be abbreviations of catalog names (BD, CPD, CoD, GSC, HIP, USNO).

Ref_Chart
This is a reference code referring to a reference containing a chart or photograph of the star field, as follows: (the codes and their corresponding references can be found in the file ftp://cdsarc.u-strasbg.fr/pub/cats/B/gcvs/refs.dat)

  "00002" - "09148" -  Vol.  I  GCVS  (see Kholopov et al., 1985-1988)
  "09149" - "09558" -  Vol. II  GCVS
  "09559" - "10200" -  Vol. III GCVS
  "67001" - "77229" -  Name-Lists Nos.67-77
  
References from Vol. V (extragalactic variables) start with the letter 'V', and references to the suspected variables start with 'N' (first part) or 'S' (supplement). References may also be abbreviations of catalog names (BD, CPD, CoD, GSC, HIP, USNO), if no chart is available for the variable, but the star is contained in one of the Durchmusterung catalogs, the Hubble Space Telescope Guide Star Catalog (GSC), the Hipparcos (HIP) Catalog, or the USNO Catalog.

Comment_Flag
This parameter is a miscellaneous flag with the following meanings:

  '='   indicates the star is also known under another variable name
  '+'   indicates the star is in other catalogs (e.g. Hipparcos or Name Lists)
  'N'   indicates the star does not exist
  

Alt_Name
An alternative designation for the variable.

Class
The HEASARC Browse object classification, based on the spectral type parameter (spect_type), if there is information in this field, else based on the variability type parameter (variability_type).


Contact Person

Questions regarding the GCVS database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 11-Dec-2012