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.
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).
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.Acknowledgment
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:
They are all thanked for their active contribution to this project.
T. Merle,
A.Tokovinin April 5, 2022