Is there any way I can tell from Hipparcos catalog which stars are Binary/Multiple Stars and which are Variable stars?
Yes. If you have the Hipparcos data from ftp (http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=I/239&-to=3), you will have several data files.
hip_main.dat you have a field
MultFlag at position 347 that indicates whether the star is a double or multiple star:
Note on MultFlag: indicates that further details are given in the Double and Multiple Systems Annex: C : solutions for the components G : acceleration or higher order terms O : orbital solutions V : variability-induced movers (apparent motion arises from variability) X : stochastic solution (probably astrometric binaries with short period)
To determine whether the star is a double or multiple star system, look in one of the files for double star solutions. For instance in
h_dm_com.dat there is a field at bytes 24-25 that gives the number of components (2 for double and >2 for multiple stars).
24- 25 I2 --- Ncomp Number of components in this solution (DCM2)
The Hipparcos number identifying the star can be found in bytes 43-48.
Of course this only works for multiple stars with orbital solutions.
For variability, three fields are provided in the main Hipparcos file:
314-320 F7.2 d Period ? Variability period (days) (H51) 322 A1 --- HvarType *[CDMPRU]? variability type (H52) 324 A1 --- moreVar * Additional data about variability (H53)
with two notes (NB. if
C then the star is constant, i.e. not variable!):
Note on HvarType: Hipparcos-defined type of variability (a blank entry signifies that the entry could not be classified as variable or constant): C : no variability detected ("constant") D : duplicity-induced variability M : possibly micro-variable (amplitude < 0.03mag) P : periodic variable R : V-I colour index was revised due to variability analysis U : unsolved variable which does not fall in the other categories Note on moreVar: more data about periodic variability are provided
There are two additional files on variability:
hip_va_2.dat, which provide information such as variable type (GCVS) and max and min magnitude and also the variable star name.
You can find a description of the variable type in the General Catalogue of Variable Stars (GCVS) in the file
vartype.txt if you download the GCVS at http://cdsarc.u-strasbg.fr/viz-bin/Cat?B/gcvs
The logic for double/multiple systems in Hipparcos is fairly complex.
Just looking at the MultFlag may not be enough. If I understand it correctly, some double/multiple stars, sharing the same CCDM identifier (field H55), appear as separate entries in Hipparcos. Many would want to consider all such entries sharing the same CCDM as belonging to the same system.
The CCDM id comes from a separate catalog of double/multiple stars. (It also comes from Hipparcos itself, which created new CCDM ids as part of its processing.)