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GCVSNSVARS: Help

GCVSNSVARS - General Catalog of Variable Stars (GCVS4.2): Suspected Variable Stars


Overview

This catalog is a compilation of 24735 stars that are suspected of variability but have not been finally designated as variables. It is the merging of a compilation of the New Catalog of Suspected Variable Stars (NSV Catalog) published in 1982 by Kukarkin et al. and available as CDS Catalog II/140, and the Version 1.0 Supplement to the NSV published in 1998 by Kazarovets et al. and available as CDS Catalog II/219. The HEASARC version of this catalog excludes 1282 entries (listed in the file ftp://legacy.gsfc.nasa.gov/heasarc/dbase/misc_files/gcvsnsvars_deleted.entries) that are now either in the main General Catalog of (Galactic) Variable Stars (the HEASARC GCVS database), or in the General Catalog of Extragalactic Variable Stars (the HEASARC GCVSEGVARS database), or are duplicates of other NSV entries. The data contained in the present catalog include positions, magnitudes, variability types, references to the literature, and spectra. The electronic version of the NSV Supplement contains principally the data tables from the printed catalog, while the textual material (bibliography, remarks) and cross-identifications list are not included but are available at the CDS in the directory ftp://cdsarc.u-strasbg.fr/pub/cats/II/250/.

Catalog Bibcode

<II/250/nsv_cat.dat>

References

Combined General Catalogue of Variable Stars (GCVS4.2, 2004 Ed.)
    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 (2004)>
New Catalogue of Suspected Variable Stars,
    Kukarkin B.V., Kholopov P.N., Artiukhina N.M., Fedorovich V.P.,
    Frolov M.S., Goranskij V.P., Gorynya N.A., Karitskaya E.A.,
    Kireeva N.N., Kukarkina N.P., Kurochkin N.E., Medvedeva G.I.,
    Perova N.B., Ponomareva G.A., Samus N.N., Shugarov S.Yu.
   <Moscow: Nauka Publishing House (1982)>
New Catalogue of Suspected Variable Stars. Supplement - Version 1.0
     Kazarovets E.V., Durlevich O.V., Samus N.N.
    <Institute of Astronomy of Russian Academy of Sciences and
     Sternberg Astronomical Institute (1998)>
    =1998IBVS.4655....1K

Provenance

This online version of the GCVS Suspected Variable Stars Catalog was created by the HEASARC in February 2005 based on CDS Catalog II/250, table nsv_cat.dat, excluding 1282 entries (see the file ftp://legacy.gsfc.nasa.gov/heasarc/dbase/misc_files/gcvsnsvars_deleted.entries) that are now either in the main General Catalog of (Galactic) Variable Stars (the HEASARC GCVS database) or in the General Catalog of Extragalactic Variable Stars (the HEASARC GCVSEGVARS database), or are known duplicates of other entries.

HEASARC Changes

The HEASARC has made a small number of mostly cosmetic changes to this catalog. Firstly, the suspected variable star names have had all their leading zeroes following the 'NSV' prefix deleted, e.g., NSV 2 rather than NSV 00002, to follow the standard naming convention. Secondly, a number of the parameters (note_flag, position_flag, alt_name_1, and exgal_flag) had possible non-alphanumeric values such as * and : in the original catalog which the HEASARC has changed to alphanumeric characters. Thirdly, the parameter limit_min_mag had a value of '<' in a number of the entries in the original catalog, which value was used to designate an upper limit to the brightness (apparently), i.e., it means a lower limit to the minimum magnitude, or that the true minimum magnitude is fainter than the tabulated minimum magnitude. The HEASARC has changed all of these occurrences from '<' to '>' in order to conform to the normal practice for indicating 'fainter than' in magnitudes.

Finally, we have excluded 1282 entries (listed in the file ftp://legacy.gsfc.nasa.gov/heasarc/dbase/misc_files/gcvsnsvars_deleted.entries) that were present in the original nsv.dat and nsvs.dat tables but had no coordinates given, indicating that the status of these suspected variable stars has now changed to confirmed galactic variable stars (and listed in the main General Catalog of (Galactic) Variable Stars, the HEASARC GCVS database), confirmed extragalactic variable stars (and listed in the General Catalog of Extragalactic Variable Stars, the HEASARC GCVSEGVARS database), or are duplicates of other NSV entries.


Parameters

Name
The GCVS Suspected Variable Star prefix NSV (for New Suspected Variable) together with a running number (from 1 to 14811 for stars in the original 1982 NSV Catalog, and from 15001 to 26206 for stars in the 1998 Supplement to the NSV). Leading zeroes have been removed from the running number. One entry (NSV 10360) has a letter suffix of A, and thus, to be completely accurate, should be referred to as NSV 10360A, according to the CDS documentation.

NSV
The NSV Catalog running number (from 1 to 14811 for stars in the original 1982 NSV Catalog, and from 15001 to 26206 for stars in the 1998 Supplement to the NSV). Leading zeroes have been removed from the running number, notice.

NSV_Suffix
The NSV Catalog letter suffix, used only for one entry (NSV 10360) which has a letter suffix of A, and thus should be referred to as NSV 10360A, according to the CDS documentation.

Variability_Flag
This is a flag that is set to the value of '-'if a star's variability seems doubtful or erroneous according to the compilers of the NSV Catalog.

Note_Flag
This is a flag that is set to 'Y' if there are remarks on the star in the file ftp://cdsarc.u-strasbg.fr/pub/cats/II/250/nsv_rem.dat

The remarks contain information covering situations such as, e.g.:

    1. The discoverer of the light variability is not the author of the
       paper cited in the variability reference, or is one of several
       authors of the paper cited.  In these cases, discoverers' names are
       given in original transcriptions of the remarks.

    2. The most important additional information about a star, although
       the NSV Supplement compilers did not intend to present complete
       bibliographies for any catalogued stars.

    3. Remarks for visual binaries giving visual magnitudes for the
       individual components A and B, angular separations, and position
       angles for faint components (or semimajor axis of a relative orbit
       and period of orbital motion). Then, data for other components are
       given where applicable. (Combined magnitudes are generally reported
       in the main database table).
  

RA
The Right Ascension of the star in the specified equinox. This was given to a precision of 0.1 seconds of time in the originating table, and in both B1950 and J2000 equatorial coordinates.

Dec
The Declination of the star in the specified equinox. This was given to a precision of 1 arcsecond in the originating table, and in both J2000 and B1950 equatorial coordinates.

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:

    'A'  means right ascensions accurate to one second of time and
         declinations accurate to one-tenth of an arcminute
    'B'  means declinations accurate to 1 arcminute
  

Variability_Type
The type of variability according to the GCVS (4th Edition) variability classification scheme, with the addition of six new types (ZZO, AM, R, BE, LBV, BLBOO) that were introduced in the Name-Lists 67-72 and in the GCVS vol. V. Descriptions of the 6 new types only are given below, while the entire classification scheme is described in the file ftp://cdsarc.u-strasbg.fr/pub/cats/II/250/vartype.txt. The new types are:

  ZZO    ZZ Cet type variables of the DO spectral type showing HeII and
         and CIV absorption lines in their spectra.

  AM     AM Her type variables; close binary systems consisting of a
         dK-dM type dwarf and of a compact object with strong magnetic
         field, characterized by variable linear and circular polarization
         of light. The total range of light variations may reach 4-5 mag V.

  R      Close binary systems characterized by the presence of strong
         reflection (re-radiation) of the light of the hot star
         illuminating the surface of the cooler companion.  Light curves
         are sinusoidal with the period equal to Porb, maximum brightness
         coinciding with the passage of the hot star in front of the
         companion.  The eclipse may be absent.  The range of light
         variation is about 0.5-1.0 mag V (KV Vel).

  BE     It becomes more and more clear that, although the majority of Be
         stars are photometrically variable, not all of them could be
         properly called GCAS variables.  Quite a number of them show
         small-scale variations not necessarily related to shell events; in
         some cases the variations are quasi-periodic.  By now we are not
         able to present an elaborated system of classification for Be
         variables, but we adopt a decision that in the cases when a Be
         variable cannot be readily described as a GCAS star we give simply
         BE for the type of variability.

  LBV    For comparatively long-period pulsating B stars (periods exceeding
         one day), we introduce a provisional type LBV.

  BLBOO  The so-called "anomalous Cepheids", i.e. stars with periods
         characteristic of comparatively long-period RRAB variables, but
         considerably brighter by luminosity (BL Boo = NGC 5466 V19).
  

Limit_Max_Mag
This is a limit flag for the maximum magnitude: '<' indicates that the max_mag value given is a numerical upper limit, i.e., the actual maximum magnitude may be brighter than this value, while '>' means that the max_mag value given is a numerical lower limit, i.e., the actual maximum magnitude may be fainter than this value.

Max_Mag
The apparent magnitude at maximum brightness. Magnitudes are reported to hundredths if the observations are photoelectric or CCD, to tenths or whole magnitudes if they are not. If only an amplitude has been measured photoelectrically, then the maximum magnitude is generally given to tenths only and the minimum is reported to hundredths.

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

Min_Mag_Type
This flag is set to '(' to indicate that the quoted min_mag value is an amplitude relative to the value of the max_mag parameter, rather than the actual minimum magnitude.

Limit_Min_Mag
This is a limit flag for the parameter min_mag, which can be either a minimum magnitude or an amplitude, notice. If the value is '>', then the min_mag value given is a bright limit, i.e., the actual minimum magnitude may be fainter than this value, while if the value is '<', then the min_mag value given is a faint limit, i.e., the actual minimum magnitude may be brighter than this value. If the value of min_mag_type is '(', this indicates that the min_mag value given is an amplitude rather than an observed magnitude, and the limit applies to this amplitude.

Min_Mag
The minimum apparent magnitude, or the amplitude of variability. If the value of limit_min_mag is '(', this indicates that the min_mag value given is an amplitude rather than an observed minimum magnitude. Magnitudes are reported to hundredths if the observations are photoelectric or CCD, to tenths or whole magnitudes if they are not. If only an amplitude has been measured photoelectrically, then the maximum magnitude is generally given to tenths only and the minimum is reported to hundredths. If the value of min_mag_flag is 'ST', then the quoted value of min_mag is an amplitude in steps rather than magnitudes, and the original references should be consulted for further information.

Min_Mag_Flag
This flag is set to ':' if the min_mag value is considered uncertain, and is set to 'ST' if the the quoted value of min_mag is an amplitude in steps rather than magnitudes, and the original references should be consulted for further information.

Min_Mag_System
A code for the photometric system in which the min_mag value is reported (given only if this is different from the photometric system in which the max_mag value is reported). The main codes are V (visual, photovisual, or Johnson V), B (Johnson B) and p (photographic magnitudes). The designations u, v, b, y refer to the Stroemgren system. The symbols Ic and Rc mean magnitudes in the Cousins I, R 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 are red magnitudes not tied to a particular system. A value of * for this parameter means that the quoted magnitude is for a white-light measurement. Several stars from the 68th Name List have values of '1.' for this parameter to designate the 1.04 micron band of the system introduced by G.W. Lockwood.

Mag_System
A code for the photometric system in which the max_mag and min_mag value are reported (if the value of min_mag_system is blank), or for the photometric system in which the max_mag value only is reported (if the value of min_mag_system is non-blank). The main codes are V (visual, photovisual, or Johnson V), B (Johnson B) and p (photographic magnitudes). The designations u, v, b, y refer to the Stroemgren system. The symbols Ic and Rc mean magnitudes in the Cousins I, R 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 are red magnitudes not tied to a particular system. A value of * for this parameter means that the quoted magnitude is for a white-light measurement. Several stars from the 68th Name List have values of '1.' for this parameter to designate the 1.04 micron band of the system introduced by G.W. Lockwood.

Ref_Star
This is a reference code referring to a study of the star, the key to which can be found in the file ftp://cdsarc.u-strasbg.fr/pub/cats/II/250/refs.dat

Ref_Chart
This is a reference code referring to a study that contains a chart or photograph of the star field, the key to which can be found in the file ftp://cdsarc.u-strasbg.fr/pub/cats/II/250/refs.dat

Alt_Name
The identification of the suspected variable in the paper whose code reference is given in the ref_star parameter. DM numbers are given without a prefix, the standard naming convention of "The Henry Draper Catalogue" being used (BD for declination zones +89 to -22, CD for zones -23 to -51, and CP for zones -52 to -89). Some identifications are given by coordinate designations, a 6-digit number consisting of hours, minutes, and seconds (or tenths of a minute) of time and degrees of declination with sign included. A value of 'Y' signifies that a designation is given in the remarks to the published catalog. This parameter is not populated for the stars in the NSV Supplement (entries with values of the nsv parameter of 15001 or greater.

Spect_Type
The spectral type and luminosity class of the suspected variable star, if known. Spectral types from the HD Catalog are generally given in parentheses. Also, the following (non-standard) symbols may be used:

                    AF   for A-F type stars
                    FG   for F-G type stars
                    KM   for K-M type stars
  

Alt_Var_Name
The alternative name of the suspected variable star either as given in the main Catalog of Galactic Variable Stars (the HEASARC GCVS table, created from the CDS table II/250/gcvs_cat.dat), a Name-List number, if it starts with the 2-digit number 67-77 and is followed by the 4-digit number of the star in the corresponding Name List, or as given in the GCVS Catalog of Extragalactic Variable Stars (the HEASARC GCVSEGVARS table, created from the CDS table II/250/evs_cat.dat). In the last case, the name may be followed by an asterisk: this indicates that there are remarks about this star in GCVS Volume V. Notice that the HEASARC removed 1282 entries (which are listed in the file ftp://legacy.gsfc.nasa.gov/heasarc/dbase/misc_files/gcvsnsvars_deleted.entries) that were present in the CDS table II/250/nsv_cat.dat but had no coordinates given, indicating that the status of these suspected variable stars had changed. The HEASARC retained other entries that have non-blank values of the alt_var_name parameter but that had valid positional coordinates and other data.

Class
The Browse object classification based on the spectral and/or variability types of the suspected variable star.


Contact Person

Questions regarding the GCVSNSVARS database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
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