DDO Radial Velocity Program: Short-Period Binaries

Slavek Rucinski

Department of Astronomy and Astrophysics, University of Toronto

Update: April 2017

The program

Bright (V < 11), nearby, short-period (P < 1 day) binary systems were systematically observed at David Dunlap Observatory with the 1.88m telescope and the Cassegrain spectrograph in 1999 to 2008 with the goal to obtain mean radial velocities and mass-ratios, with an eventual goal of complete light and radial-velocity synthesis model solutions giving system parameters and distances accurate at better than 3% level.

Since contact binaries of the W UMa-type appear to be very numerous in space, with the relative spatial frequency of about 1/500 of FGK dwarfs in the solar vicinity (Rucinski 2002a, 2006a), most of the targets were EW binaries, but with an admixture of EB and EA close binaries. It should be noted that most of the targets have been observed spectroscopically for radial velocity variations for the first time.

The DDO survey ended on July 2, 2008 with the closure of the observatory. We achieved ~92% completeness for known binaries with P < 1 day, V < 10, del > -25 deg; we needed probably only a few more months to finish the survey. In total, 162 binaries were observed with 145 of them giving double-line spectral RV data (SB2), hence the full set of spectroscopic parameters V0, K1, K2; only 5 were dingle-line binaries (SB1), probably with white or brown dwarfs as we could easily detect Main Sequence components down to the mass ratios as small as about 0.05 or even less. Most binaries, 121 among the SB2s, were contact binaries. This is currently the most complete, consistent and comprehensive radial-velocity survey of close binary stars.

Hopefully, the RV data will contribute to our understanding of WUMa-type binaries. This class of binaries still does not have an unambiguous physical description. While the model of Lucy will in 2018 celebrate its 50th anniversary, we are not sure if it applies to all cases. AW UMa, for long considered the flag case for the model, was shown with much more detailed spectroscopy than that of DDO that it is not a Lucy-model contact system (Rucinski 2015) [although in a DDO paper (Pribulla and Rucinski 2008) we did see most of the problems, but not in such perfect detail].

While its results were used in numerous papers (including many preposterous "photometric improvements" of radial-velocity data), the survey has been described more fully in only two short summary papers:

Here are the printed, final versions of the papers in the PDF format:

Paper I
Paper II
Paper III
Paper IV
Paper V
Paper VI
Paper VII (expl.)
Paper VIII
Paper IX
Paper X
Paper XI
Paper XII
Paper XIII
Paper XIV
Paper XV

Tables of ascii data (note that AJ changed the column format between the papers, so your reader program must accommodate that):
Table 1, Pap. I
Table 1, Pap. II
Table 1, Pap. III
Table 1, Pap. IV
Table 1, Pap. V
Table 1, Pap. VI
Table 1, Pap. VIII
Table 1, Pap. IX
Table 1, Pap. X (corrected)
Tables 1 and 3, Pap. XI
Tables 1 and 3, Pap. XII
Table 1, Pap. XIII
Tables 1 and 2, Pap. XIV
Tables 1, 3 and 5, Pap. XV

When you publish a paper based on the above data, please: (1) Inform the undersigned by e-mail, (2) Enclose a footnote in the front page of your paper: "Based on the data obtained at the David Dunlap Observatory, University of Toronto."

Other papers based on the DDO Binary Star Program data:
AH Vir
W Crv
GSC 1387-475 (shortest period EW)
Contact binaries in triple systems I
Contact binaries in triple systems II
Contact binaries in triple systems III
Metallicities of contact binaries

The binary program described above was conducted with the use of the 1.88m telescope and a Cassegrain medium-resolution spectrograph in its highest-resolution mode. The spectrograph had several gratings permitting other resolutions (R = 4,000 - 15,000), but the program used almost exclusively the highest resolving power of R ~ 15,000.


Contact: Slavek Rucinski: rucinski(AT)astro.utoronto.ca