Introductory notes

  1. Presentation
  2. Structure of data
  3. Acknowledgment


The Eighth catalog of the orbital elements of spectroscopic binary stars (SB8 - Batten A.H., Fletcher J.M., Mac Carthy D.G. 1989, Publ. DAO, V. 17) contains the orbits published until January 1, 1988. There was no continuation of this work at DAO, hence at the 24th IAU GA (Manchester, 2000) it was decided to create a working group and to update the catalog. Unlike SB8, the new catalog, SB9, will not be published on the paper but will be accessible through Internet. It will be continuously updated with new orbits.

Compilation of the SB9 is done by a team of contributors, distributed all over the world. Authors of new orbits are encouraged to contribute their data directly. Due to the ever increasing volume of data, the amount of additional information supplied for each new system in the notes will be less than in SB8. On the other hand, SB9 contains several orbits per system (when available) and individual radial velocities, also when available. References are linked to ADS bibliographic service.

We feel that SB9 will be as useful to the community as its predecessors, enabling statistical studies, selection of targets for further observations, and giving an overall picture of the progress in the studies of spectroscopic binaries.

Structure of data

Upon entering the WEB page of SB9, you can search for your object of interest by its identifier in common catalogs (like HD, BD, HIP), by bibcode of the publication, or by coordinates. Uncommon identifiers (e.g. nearby stars or cluster members) can be tried by selecting 'Misc', then entering identifier and number, separated by space.

When the object is found, its basic data are displayed: coordinates, identifiers, component identifier (for multiple systems), magnitudes and spectral types (of both components when available or 'combined'). Each system has its internal number in SB9; the first 1439 numbers are identical to those of SB8, the next are assigned sequentially and are, generally, of little use. If there are more than one orbits for a given system, you select the orbit to display.

The listing of orbital elements is self-explanatory. Their formal errors are also listed when available. Fixed elements contain '*' instead of errors; for circular orbits, eccentricity and longitude of periastron are fixed at zero. Grades of old orbits are taken from SB8 (5 - best, 1 - worst), for new orbits they are not entered, pending a development of new automatic grading system. If some of the elements (e.g. center-of-mass velocity V0) were determined separately for primary and secondary components of double-lined binaries, only the values for primary are listed, because the elements are meant to reflect actual keplerian motion of stars rather than radial-velocity curves from which they are derived.

Text of note follows the elements. Then, whenever individual radial velocities are available, they are listed and a plot of radial velocity curve is displayed. Each measurement contains formal error of velocity, weight (as used in least-squares fitting of orbital elements), component identifier ('a' for primary, 'b' for secondary) and optional comments or flags (e.g. reference to instruments used to take data).


Besides the members of the SB9 working group of the IAU Commission 30, several individuals have actively contributed (and are still contributing) to the growth of SB9:
  1. Roger Griffin: 45 papers + 100 RV sets in electronic format
  2. Jean-Michel Carquillat, Maurice Imbert, Alain Jorissen
  3. Laszlo Szabados (orbits and RV of cepheids)
  4. Dave Stickland (IEU orbits and data)
  5. Elena Glushkova (lots of orbits from Russian authors)
  6. Roger Leiton (data entry)
They are all thanked for their active contribution to this project.
T. Merle, A.Tokovinin
April 5, 2022