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Fourth Catalog of Interferometric Measurements of Binary Stars

 (catalog files are updated whenever new data are added to the database; statistics were last updated 18 July 2016)


The following description is adapted from a paper by Hartkopf et al. (2001, AJ, 122, 3480.)

The Fourth Catalog of Interferometric Measurements of Binary Stars includes all published measures of binary and multiple star systems obtained by high-resolution techniques (speckle interferometry, photoelectric occultation timings, etc.), as well as negative examinations for duplicity. A brief summary and statistical analysis of the contents of the catalog follow.



The Fourth Catalog of Interferometric Measurements of Binary Stars began in 1982 as an internal database at the Georgia State University Center for High Angular Resolution Astronomy (CHARA), tabulating binary star observations made using the technique of speckle interferometry by that group's speckle camera. The Speckle Catalog soon grew to encompass other published speckle efforts, then all published astrometric and photometric data for binary stars (and single stars observed in duplicity surveys) obtained by other high angular resolution techniques (lunar occultations, adaptive optics, eyepiece interferometry, Hipparcos, etc.) as well. This extended the catalog's baseline of observations back by nearly a century, to the efforts of Schwarzschild & Villiger (1896). Results of surveys based on various infrared speckle or imaging techniques were later added, as well, even though some of these don't really qualify as "high resolution".


Two printed editions of the catalog were published in the 1980's (McAlister & Hartkopf 1984, 1988), and web versions have been available since the early 1990's (Hartkopf et al. 2001a, 2001b). After the speckle efforts at CHARA were suspended in the late 1990's (in order to devote more resources to their long-baseline interferometry project) one of the authors (WIH) transferred the catalog (still nicknamed the Speckle Catalog in honor of its origins) to the U.S. Naval Observatory, whose own speckle efforts had begun earlier in the decade.



Catalog Description


The table below summarizes the contents of the catalog as of 18 July 2016. In addition to the astrometric totals presented here, the catalog includes 72,570 observations of photometric data only. In total astrometric observations, the Fourth Speckle Catalog is about 40 times the size of the First Catalog, 17 times the size of the Second, and well over twice the size of the 2001.0 Third Catalog. Figures 1 - 3 illustrate the distribution of catalog data with time, separation, and declination, respectively.



       Fourth Interferometric Catalogue Statistics (as of 18 July 2016)     
            Number of resolved stars:                      62,976
	    Number of never-resolved stars:                25,450
            Total number of stars:                         88,426 
            Median separation                               0".89

        Breakdown of data by method:             
                                          resolved  unresolved   total

            Tycho                          40.853      1,001     41,854 
            Hipparcos                      13,880     16,800     30,680   
            USNO Speckle                   22,294      4,759     27,053                        
            CHARA Speckle                  18,525      6,479     25,004  
            Other speckle, AO, etc         27,926     11,091     39,017   
            Eyepiece interferometry         3,085        700      3,785   
            Occultation                     1,816        770      2,586   
            Multi-aperture interferometers  3,099      1,050      4,149   
            Hubble                          1,709      3,568      5,277   
            Other techniques               17,392     31,640     49,032
            TOTAL                         150,579     77,858    228,437

        Of the resolved total, 2,461 are vector separations (from either
        occultations or one-dimensional IR speckle).




The catalog is divided into 24 one-hour right ascension bands, as follows:






The entire catalog is also available in plain text and gzipped plain text versions. Sizes are roughly 44 and 8MB, respectively.


Entries for each system are comprised of two parts: an identification line containing designations from various catalogs, followed by individual measures sorted in order of observation date (see the format file). Major changes with this version include coordinates to 0.01s in RA and 0".1 in DEC, improvements in the formatting of filter information to allow longer wavelengths, and the addition of technique codes. The ID line format was changed slightly in July 2007 to allow additional space for long names (e.g., 2MASS designations). Each observation includes a reference code linked to a reference file. Similarly, systems having notes are flagged with links to a notes file. An additional change in July 2007 provided links to the Sixth Orbit Catalog for pairs with published visual or astrometric orbits. In October 2007 we completed a merger of the notes files for the WDS with those of the Interferometric and Orbit catalogs. As a result, the notes file will include systems in addition to those in this catalog. Also, because the notes file is much larger, it has been divided into 24 smaller files for faster linking to the individual catalog measurements files.


Your comments regarding either style or substance are welcome. Please report any errors you run across in the catalog to the authors.


  • Anderson, J.A. 1920, ApJ 51, 263
  • Hartkopf, W.I., Mason, B.D., McAlister, H.A., Turner, N.H., Barry, D.J., Franz, O.G., & Prieto, C.M. 1996 AJ, 111, 936
  • Hartkopf, W.I., McAlister, H.A. & Mason, B.D. 2001a, Third Catalog of Interferometric Measurements of Binary Stars, CHARA Contrib. No. 4
  • Hartkopf, W.I., Mason, B.D., Wycoff, G.L., & McAlister, H.A. 2001b, Fourth Catalog of Interferometric Measurements of Binary Stars
  • Horch, E.P., Franz, O.G., & Ninkov, Z. 2000, AJ 120, 2638
  • McAlister, H.A. & Hartkopf, W.I. 1984, Catalog of Interferometric Measurements of Binary Stars, CHARA Contrib. No. 1
  • McAlister, H.A. & Hartkopf, W.I. 1988, Second Catalog of Interferometric Measurements of Binary Stars, CHARA Contrib. No. 2
  • Merrill, P.W. 1922, ApJ 56, 40
  • Schwarzschild, K. & Villiger, W. 1896, Astr. Nach. 139, 353