J/MNRAS/456/2070 Eccentricity distribution of wide binaries (Tokovinin+, 2016)
Eccentricity distribution of wide binaries.
Tokovinin A., Kiyaeva O.
<Mon. Not. R. Astron. Soc., 456, 2070-2079 (2016)>
=2016MNRAS.456.2070T 2016MNRAS.456.2070T (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple
Keywords: methods: statistical - binaries: visual
Abstract:
A sample of 477 solar-type binaries within 67pc with projected
separations larger than 50AU is studied by a new statistical method.
Speed and direction of the relative motion are determined from the
short observed arcs or known orbits, and their joint distribution is
compared to the numerical simulations. By inverting the observed
distribution with the help of simulations, we find that average
eccentricity of wide binaries is 0.59±0.02 and the eccentricity
distribution can be modelled as f(e)∼1.2e+0.4. However, wide binaries
containing inner subsystems, i.e. triple or higher order multiples,
have significantly smaller eccentricities with the average
e=0.52±0.05 and the peak at e∼0.5. We find that the catalogue of
visual orbits is strongly biased against large eccentricities. A
marginal evidence of eccentricity increasing with separation (or
period) is found for this sample. Comparison with spectroscopic
binaries proves the reality of the controversial period-eccentricity
relation. The average eccentricity does increase with binary period,
being 0.39 for periods from 102 to 103d and 0.59 for the binaries
studied here (105-106d).
Description:
Our main sample consists of solar-type binary systems within 67pc from
(Tokovinin, 2014, Cat. J/AJ/147/86, hereafter FG-67) with projected
separations r>50au. The initial selection of 886 physical pairs was
further filtered by the criterion µ*>10mas/yr, leaving 344 objects.
This restriction is dictated by the accuracy of LMP determination from
the available data. The masses of both components (including known
subsystems) needed for the calculation of µ* are taken from the
FG-67 compilation, the parallaxes are from (van Leeuwen 2007, Cat.
I/311).
The main sample was complemented by additional binaries from the
Hipparcos catalogue with parallax larger than 15 mas and projected
separation larger than 50au (minimum separation of 0.75 arcsec at a
distance of 67pc).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 68 575 Wide binaries within 67pc
table3.dat 113 477 LMPs of binaries
--------------------------------------------------------------------------------
See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2014)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- HIP Hipparcos number of primary component
8- 17 A10 --- WDS WDS J2000 code
19- 34 A16 --- Disc Discoverer code and components 1
36- 40 F5.1 mas Plx Hipparcos-2 parallax
42- 47 F6.1 AU Sep Projected separation
49- 52 F4.2 Msun M1 Mass of the primary component
54- 57 F4.2 Msun M2 Mass of the secondary component
59- 63 F5.1 mas/yr mu* Characteristic speed of relative motion
65- 66 A2 --- Type [CLOM ] Type of motion
68 A1 --- Tag [MEme] Sample tag
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
-------------------------------------------------------------------------------
1- 6 I6 --- HIP Hipparcos number of primary component
8 A1 --- Type [LCO] Type of motion from Table 2
10- 15 F6.1 yr t0 Reference epoch (1)
17- 23 F7.3 deg theta0 Position angle at moment t0
25- 30 F6.3 deg/yr theta1 Speed of angular motion
32- 37 F6.3 arcsec rho0 Separation at moment t0
39- 45 F7.4 arcsec/yr rho1 Speed of radial motion
47- 51 F5.1 mas/yr mu Speed of relative motion
53- 58 F6.1 deg gamma Angle of relative motion w.r.t. radius
60- 63 F4.2 --- mu1 Normalized relative motion (1)
65- 69 F5.1 yr DeltaT ? Time span (1)
71- 75 F5.3 deg e_theta0 ? rms uncertainty on theta0 (1)
77- 81 F5.3 deg/yr e_theta1 ? rms uncertainty on theta1 (1)
83- 87 F5.3 arcsec e_rho0 ? rms uncertainty on rho0 (1)
89- 94 F6.4 arcsec/yr e_rho1 ? rms uncertainty on rho1 (1)
96- 99 F4.1 mas/yr e_mu ? rms uncertainty on mu (1)
101-104 F4.1 deg e_gamma ? rms uncertainty on gamma (1)
106-108 F3.1 deg resgamma ? rms residual in angle (1)
109 A1 --- --- [/]
110-113 F4.2 arcsec resrho ? rms residual in separation (1)
--------------------------------------------------------------------------------
Note (1): For entries of types L and C.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Sep-2016