The Formation of Contact and Very Close Binaries Page: 4 of 13
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
2
Tokovinin et al. (2007) considered a sample of 161 stellar systems con-
taining spectroscopic binaries (SBs) with periods <30 d, and looked (by
adaptive optics) for companions, for those for which companions were not
already known. They found that among those with period < 3 d, 32 out of 41
were triple; and making allowance, by a maximum-likelihood procedure, for
incompleteness they concluded that the fraction of triples must be ~96%.
For SBs with periods > 12 d the figure was lower (34%). We therefore feel
that there is a good case for the hypothesis that very close binaries form as
a consequence of the presence of a third body. The mechanism seems likely
to be a combination of Kozai cycles with tidal friction (KCTF hereafter,
following Eggleton & Kisseleva-Eggleton 2006). For the closest binaries, i.e.
the contact binaries, we have to add another mechanism, magnetic braking
also combined with tidal friction (MBTF hereafter).
For a recent discussion of Kozai cycles, and the KCTF mechanism, see
Fabrycky & Tremaine (2007). Earlier discussions have been by Mazeh &
Shaham (1979) and Kiseleva, Eggleton & Mikkola (1998; hereafter KEM98),
for instance. The orbit of the third body has to be inclined by at least 390
to the orbit of the close pair and at most 1410; for present purposes it is
adequate to assume that the behavior is symmetric about 900. If third-
body orbits are assumed to be randomly oriented relative to the inner pair
then the distribution of cos q, where q is the mutual inclination, should be
uniform. Thus the probability is 50% that > 600, and at this inclination
Kozai cycles can already be quite large, with the eccentricity cycling be-
tween zero and 0.76 (or between 0.3 and 0.81; see Eggleton 2006, Table
4.9).
Although determining the inclination of each orbit to the line of sight is
not difficult in favorable cases, determination of the mutual inclination is
rather difficult. Muterspaugh et al. (2006) list just six systems for which '
has been determined. These inclinations range from 240 to 1320; two are
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
Kisseleva-Eggleton, L & Eggleton, P P. The Formation of Contact and Very Close Binaries, article, August 10, 2007; Livermore, California. (https://digital.library.unt.edu/ark:/67531/metadc894913/m1/4/: accessed April 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.