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.

In 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  *[12] Additional data about variability   (H53)

with two notes (NB. if HvarType is 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_1.dat and 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

| improve this answer | |
  • $\begingroup$ Meant to add Variable stars as well, is that available from hipparcos? $\endgroup$ – MiscellaneousUser Apr 17 '15 at 12:51
  • $\begingroup$ What is meant by Orbital Solutions? $\endgroup$ – MiscellaneousUser Apr 17 '15 at 13:03
  • $\begingroup$ Yes on variable stars, see my edit of the answer. $\endgroup$ – Dieudonné Apr 17 '15 at 13:06
  • $\begingroup$ Orbital solutions are used to calculate the orbit of one star in the binary with respect to the other star. They can be found in the file 'hip_dm_o.dat'. $\endgroup$ – Dieudonné Apr 17 '15 at 13:09

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