Washington Double Star Catalog 2014

[drollere]

i've recently completed my 2014 edition of the Washington Double Star catalog (WDS), formatted with "dark adaptation" red type on black background, and available at this link:

http://www.handprint.com/ASTRO/XLSX/WDS2014.xlsx

the dataset now contains 125,975 records of data describing 107,263 double star systems and is 58 Mb large.

a shortened version that excludes all *systems* with a primary star fainter than 10.5 but includes all components regardless of magnitude is available at: 

http://www.handprint.com/ASTRO/XLSX/ShortWDS2014.xlsx

this contains 42,338 systems in 55,512 records at a slimmer (laptop friendly) 25 Mb.

NOTE: both files are in .xlsx, so old versions of microsoft excel will not open them. 

in the full WDS, the median system distance is 176 parsecs, median orbital radius is 940 AU, average period ~20,000 years, and median mass ratio 0.8. in the ShortWDS, the median system distance is 162 parsecs, median orbital radius is 900 AU, the average period ~20,000 years, and median mass ratio 0.63. due to a variety of selection biases in WDS itself, the ShortWDS has proportionately more multiple stars (15% vs. 9%), fewer matched binary stars (13% vs. 25%), and fewer wide binaries (3% vs. 6%). 

as before, the data append hipparcos or spectroscopic parallax estimates of system distance, estimated orbital radius for each component, and orbital period either from the 6th Orbit Catalog or estimated from radius assuming a 2 solar mass system. hipparcos values are truncated at 1000 parsecs and spectroscopic values at 5000 parsecs; orbital distances greater than 100,000 parsecs are denoted "optical" unless the system is a confirmed CPM system, in which case the value is retained as a validity check. hipparcos estimates supersede the spectroscopic estimates in all binary systems, but multiple systems may show both estimates as a sobriety check on the precision of astronomical distance calculations, and to identify possibly unidentified optical components. to refine the spectroscopic parallax estimates, apparent magnitudes have been corrected using values from allen's "astrophysical quantities" when a B, R or K filter system has been used. 

the statistical test for physicality by Sinachopoulos & Mouzourakis (1991) has been applied to every record, and systems with a 95% all sky probability of being physical pairs are flagged in the notes column. combined with the WDS records flagged as physical through orbital, CPM or parallax evidence, there are now 29,400 highly probable or confirmed physical pairs in the dataset -- 27% of total. 

Flamsteed/Bayer designations, primary star popular name and AAVSO variable designation are appended using the USNO concordance, which has been corrected and augmented by several matches made while checking systems in SIMBAD.

there are several derived variables -- change in position angle, change in separation, magnitude difference, number of system components, mass ratio, and both net proper motion and the divergence between the proper motions in every pair with full PM data. this divergence number reveals a large number of pairs with very low (but nonzero) divergence as a ratio of total proper motion, which strongly implies they are physical also. proper motions calibrated on 100 rather than 1000 years to conserve space in the original data file have been multiplied by 10 to exclude confusion. high proper motion stars can be spotted easily.

galactic coordinates have been calculated to three decimal places (+/- 4 arcseconds) and match SIMBAD values exactly. for anyone familiar with the galactic coordinate relationship to galaxy structure, these are invaluable to quickly place systems in relation to disk or halo populations, spiral arms, star forming or dusty regions, the gould belt, or stellar streams.

there is an estimate of the minimum aperture necessary to resolve each pair. in the full WDS the median is 437mm; in the ShortWDS it is 316mm. in fact most observers will find this an easy criterion to beat: the number is mostly useful as a relative ranking of visual difficulty across systems. there are several systems accessible to the naked eye (6mm), and dozens that require an aperture greater than 10 meters.

"bogus" or "optical" binaries are retained, as they are often visually distinctive in the double star appearance, but the records are displayed in blue type and no statistics are computed on them. about 50 records in WDS were identified as *both* "optical" and "physical" in the WDS notes (!), which in many cases reflect disagreement in the literature. of these, i have put 30 into the physical status. 

the 1806 deleted records included only those with missing celestial coordinates, missing position angle or separation, zero observations, or missing primary magnitude. all edits are described in the editor's notes sheet.

i have been greatly helped in this version by a collaboration with Joe Novak, who contacted me to review a WDS query tool he was developing. one thing led to another, and i have suggested several added features; thanks to his programming skill, the dataset includes accurate counts of system components and the corrected spectroscopic estimates, which are not available in any other data set. 

along the way i discovered several errors in the WDS data and, surprisingly, even errors in SIMBAD. these have all been corrected.

remaining errors are mine, and i'd greatly appreciate notification of any you may discover.

enjoy.