J/A+A/574/A6 Study of 95 binaries closer than 18pc from the Sun (Agati+, 2015)
Are the orbital poles of binary stars in the solar neighbourhood
anisotropically distributed?
Agati J.-L., Bonneau D., Jorissen A., Soulie E., Udry S., Verhas P.,
Dommanget J.
<Astron. Astrophys., 574, A6-6 (2015)>
=2015A&A...574A...6A 2015A&A...574A...6A
ADC_Keywords: Stars, double and multiple ; Stars, nearby
Keywords: binaries: visual - binaries: spectroscopic -
techniques: radial velocities - techniques: high angular resolution -
methods: statistical - solar neighborhood
Abstract:
We test whether or not the orbital poles of the systems in the solar
neighbourhood are isotropically distributed on the celestial sphere.
The problem is plagued by the ambiguity on the position of the
ascending node. Of the 95 systems closer than 18pc from the Sun with
an orbit in the 6th Catalogue of Orbits of Visual Binaries, the pole
ambiguity could be resolved for 51 systems using radial velocity
collected in the literature and CORAVEL database or acquired with the
HERMES/Mercator spectrograph. For several systems, we can correct the
erroneous nodes in the 6th Catalogue of Orbits and obtain new combined
spectroscopic/astrometric orbits for seven systems
[WDS 01083+5455Aa,Ab; 01418+4237AB; 02278+0426AB (SB2); 09006+4147AB
(SB2); 16413+3136AB; 17121+4540AB; 18070+3034AB]. We used of spherical
statistics to test for possible anisotropy. After ordering the binary
systems by increasing distance from the Sun, we computed the
false-alarm probability for subsamples of increasing sizes, from N=1
up to the full sample of 51 systems. Rayleigh-Watson and Beran tests
deliver a false-alarm probability of 0.5% for the 20 systems closer
than 8.1pc. To evaluate the robustness of this conclusion, we used a
jackknife approach, for which we repeated this procedure after
removing one system at a time from the full sample. The false-alarm
probability was then found to vary between 1.5% and 0.1%, depending on
which system is removed. The reality of the deviation from isotropy
can thus not be assessed with certainty at this stage, because only so
few systems are available, despite our efforts to increase the sample.
However, when considering the full sample of 51 systems, the
concentration of poles toward the Galactic position l=46.0°,
b=37°, as observed in the 8.1pc sphere, totally vanishes (the
Rayleigh-Watson false-alarm probability then rises to 18%).
Description:
The selection of the 95 systems in the master sample presented in
Tables 1 and 2 was based on the availability of a visual or an
astrometric orbit in the 6th Catalog of Orbit of Visual Binary Stars
at USNO (6th COVBS2, Hartkopf et al. 2001) and of a Hipparcos parallax
(ESA 1997) larger than 50mas.
Radial-velocity measurements were searched for in the literature and
among unpublished measurements obtained with the CORAVEL
spectrovelocimeter.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 60 95 Cross-identifications for the master list of 95
systems closer than 20pc from the Sun and the are
known to have an orbit in the 6th COVBS at USNO
table2.dat 99 95 Data and references for the 95 systems of the
master list
table3.dat 105 51 Position of the 51 orbital poles in Galactic
coordinates for systems closer than 18pc
appena.dat 80 416 Individual notes
refs.dat 187 77 References
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See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2014)
B/sb9 : SB9: 9th Catalogue of Spectroscopic Binary Orbits (Pourbaix+ 2004-2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- WDS WDS name (Cat. B/wds)
11- 15 A5 --- Comp WDS components
17- 28 A12 --- CCDM CCDM name (Cat. I/274)
30- 35 I6 --- HIP ?=- HIP/HIC name (Cat. I/239)
38- 43 I6 --- HD ?=- HD name (Cat. III/135)
44- 45 A2 --- m_HD Multiplicity index on HD
47- 50 I4 --- SB9 ?=- SB9 number (Pourbaix et al., 2004, B/sb9)
52- 60 A9 --- Name Discoverer name
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- WDS WDS name
11- 15 A5 --- Comp WDS components
17- 21 F5.1 mas plx Parallax (1)
23- 34 A12 --- SpType MK spectral type
36- 43 F8.3 yr Per [0.02/3200] Orbital period
45- 51 F7.4 arcsec a [0.001/42] Orbital semi-major axis
52- 56 F5.2 Msun Mtot ?=- Total mass of the system
58- 61 F4.2 --- q [0.3/1.7]?=- Mass ratio MB/MA
63 I1 --- Gr [1/9] Grade of the orbit, 1=best
65- 72 A8 --- Ref1 Visual orbit reference, in refs.dat file
75- 90 A16 --- Ref2 Spectroscopic orbit reference, in refs.dat file
92- 96 A5 --- A Flag indicating whether the system has (or not)
been considered in the final analysis (2)
98- 99 A2 --- Note [nt] t: triple or higher-multiplicity systems
noted and/or n: note in appena.dat file
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Note (1): Parallax is for all HIP entries from the revised Hipparcos Catalogue
(van Leeuwen, 2007, Cat. I/311), or from the paper listing the orbit otherwise.
Note (2): Flag as follows:
Y = yes
NO = no reliable visual orbit
NV = no radial velocities,
ND = no visible drift in the velocities, because either the period
is too long or the velocities too inaccurate
IC = inconclusive analysis
For systems with a combined visual and spectroscopic solution computed
by Pourbaix (2000A&AS..145..215P 2000A&AS..145..215P), the orbital elements were adopted
without an additional verification because the method naturally lifts
the ambiguity on the ascending node.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- WDS WDS name
11- 15 A5 --- Comp WDS components
17- 21 F5.1 deg i [0/180] Inclination angle
23- 27 F5.1 deg Omega [0/360] Longitude of ascending node Ω
29- 33 F5.1 deg omega [0/360] Longitude of the periastron of
the visual orbit ω (1)
35- 41 F7.3 deg RAdeg Right ascension of the orbital pole (J2000)
43- 49 F7.3 deg DEdeg Declination of the orbital pole (J2000)
51- 55 F5.1 mas plx Parallax
57- 61 F5.1 deg Glon Galactic longitude of the orbital pole
63- 67 F5.1 deg Glat Galactic latitude of the orbital pole
69- 76 F8.5 --- x [-1/1] X polar coordinate [cos(Glon).cos(Glat)]
78- 85 F8.5 --- y [-1/1] Y polar coordinate [sin(Glon).cos(Glat)]
87- 94 F8.5 --- z [-1/1] Z polar coordinate [sin(Glat)]
96- 99 F4.1 pc Dist [0/18] Distance
101-102 I2 --- N [1/51] Rank of system in order of increasing
distance
104-105 A2 --- Note [nt] t: triple or higher-multiplicity systems
noted and/or n: note in appena.dat file
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Note (1): Position of the longitude of periastron of the visual orbit (B with
respect to A; it differs by 180° from the value for the spectroscopic
orbit of A with respect to the centre of mass).
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Byte-by-byte Description of file: appena.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- WDS WDS name
11- 15 A5 --- Comp WDS components
17- 80 A64 --- Note Text of the note
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Ref Reference code
10- 28 A19 --- BibCode BibCode
30- 47 A18 --- Aut Author's name
49-187 A139 --- Com Comments
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 06-Mar-2015