Web interface See also: Vizier: J/ApJS/235/6 (click on the WDS code to get information on each system).

Multiple Star Catalog (MSC)

This is a catalog of hierarchical multiple stellar systems with three or more components. These systems are organized as "nested" binaries, their structure is reflected in the binary-tree ("mobile") diagrams like the one on the right, representing the Castor system with 6 components. The MSC contains about 2000 hierarchical systems with 3 to 7 components each.

Structure of the Catalog

The MSC consists of four tables linked by the common WDS code, unique for each system (see the picture on the left).

The main table comp gives basic data (position, identifiers, magnitudes, etc.) on the main component of each system. If there are several components with such information, there are also entries for the secondary components, distinguished from the primary by their non-zero separation (usually >10arcsec).

The table sys lists data on the individual sub-systems: the components' identifiers ("parent" indicates the location of each subsystem in the hierachy, starting with the upper-level root system with parent "*"). Type of the system indicates the observing techniques used to detect and study it (e.g. "v" for close visual binaries). Then follow the period, separation, magnitudes and estimated masses of the primary and secondary components.

The orb table gives the orbital elements when available, in standard notation. Comments on each multiple system can be found in the table notes.

The MSC is described in the original paper (Tokovinin, A. MSC - a catalogue of physical multiple stars. Astron. Astrophys. Suppl. Ser., 1997, 124, 75-84).

The latest updated version of the MSC is described here (Tokovinin, A. The updated Multiple Star Catalog. 2018, ApJS, 235, 6; see also the journal link ).

Access to the MSC

MSC web interface

The MSC web interface is programmed by Alex Serbul from the company Qsoft in July 2005.

Notes on the tables


Missing numerical values are displayed as zeros!

The periods of wide binaries are estimated from separations, parallaxes and masses, as explained in the paper. Similarly, the separations of close binaries are estimated from their periods. The exact meaning of the "period" and "separation" columns depends uniquely on the type of the system.

System type codes

Mass codes

Please, direct bug reports and other comments to A.Tokovinin, andrei.tokovinin-AT-noirlab.edu or andrei.tokovinin-AT-gmail.com

Last modified: Dec 29, 2023