J/ApJ/844/103 Orbit alignment in triple stars (Tokovinin, 2017)
Orbit alignment in triple stars.
Tokovinin A.
<Astrophys. J., 844, 103 (2017)>
=2017ApJ...844..103T 2017ApJ...844..103T
ADC_Keywords: Stars, double and multiple ; Binaries, orbits ;
Parallaxes, trigonometric
Keywords: binaries: general; stars: formation
Abstract:
The statistics of the angle Φ between orbital angular momenta in
hierarchical triple systems with known inner visual or astrometric
orbits are studied. A correlation between apparent revolution
directions proves the partial orbit alignment known from earlier
works. The alignment is strong in triples with outer projected
separation less than ∼50au, where the average Φ is about 20°.
In contrast, outer orbits wider than 1000 au are not aligned with the
inner orbits. It is established that the orbit alignment decreases
with the increasing mass of the primary component. The average
eccentricity of inner orbits in well-aligned triples is smaller than
in randomly aligned ones. These findings highlight the role of
dissipative interactions with gas in defining the orbital architecture
of low-mass triple systems. On the other hand, chaotic dynamics
apparently played a role in shaping more massive hierarchies. The
analysis of projected configurations and triples with known inner and
outer orbits indicates that the distribution of Φ is likely
bimodal, where 80% of triples have Φ<70° and the remaining
ones are randomly aligned.
Description:
The data on hierarchical systems are extracted from the Multiple Star
Catalog (MSC; Tokovinin 1997, J/A+AS/124/75).
See section 2 for further details.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . this file
table1.dat 77 443 Hierarchical systems with resolved inner orbit
table3.dat 61 110 Hierarchical systems with two known visual orbits
refs.dat 78 52 References
--------------------------------------------------------------------------------
See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2014)
J/AJ/111/370 : Orbits of 37 close visual systems (Hartkopf+ 1996)
J/A+AS/124/75 : Multiple star catalogue (MSC) (Tokovinin 1997-1999)
J/A+A/341/121 : Visual binary orbits and masses (Soederhjelm 1999)
J/AJ/119/3084 : ICCD speckle obs. of binary stars. XXIII. (Hartkopf+, 2000)
J/AJ/123/1023 : Binary star orbits (Seymour+, 2002)
J/A+A/384/1030 : Orientation of orbits in triple stars (Sterzik+, 2002)
J/AJ/132/2219 : Speckle interferometry at USNO. XII (Mason+, 2006)
J/AN/330/55 : PISCO speckle observations in 2006 (Scardia+, 2009)
J/AJ/140/1657 : PHASES diff. astrometry data archive V. (Muterspaugh+, 2010)
J/AJ/147/86 : From binaries to mult. I. FG-67 sample (Tokovinin, 2014)
J/AJ/149/195 : Spectro. of the quadruple system HD 91962 (Tokovinin+, 2015)
J/AJ/150/50 : Speckle interferometry at SOAR in 2014 (Tokovinin+, 2015)
J/ApJ/799/4 : Robo-AO observations of binary stars (Riddle+, 2015)
J/MNRAS/455/4136 : Kepler triples (Borkovits+, 2016)
J/A+A/594/A55 : xi Tau UBV and MOST light curves (Nemravova+, 2016)
J/AJ/152/213 : Interferometry & spectro. of sigma Orionis (Schaefer+, 2016)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- WDS WDS code (HHMMm+DDMM; J2000)
12- 16 F5.1 mas Plx [0.8/742.1] Hipparcos parallax
18- 22 F5.2 Msun M1 [0.05/50] Primary mass in the inner subsystem
24- 29 F6.1 yr P1 [0.1/3962.5] Inner period
31- 35 F5.3 --- e1 Inner eccentricity
37- 42 F6.3 arcsec a1 [0.001/32.4] Inner semimajor axis
44- 48 F5.1 deg W1 [0/357] Inner node Ω1
50- 54 F5.1 deg i1 [0/283] Inner inclination
56- 62 F7.2 arcsec Sep [0.05/7860] Outer separation ρ
64- 68 F5.1 deg PA Outer position angle θ
70- 71 I2 --- RevDir [-1/1] Outer revolution direction
(-1 for retrograde; 0 for unknown)
73- 77 I5 --- Sign [-1/1] Apparent revolution (1=corotating;
-1=counter-rotating)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- WDS WDS code (HHMMm+DDMM; J2000)
12- 12 A1 --- I/O Inner or outer subsystem
14- 20 F7.2 yr P [0.01/1431] Period
22- 26 F5.3 --- e Eccentricity
28- 32 F5.3 arcsec a [0/7.7] Semimajor axis
34- 38 F5.1 deg W [0/345] Position angle of node Ω
40- 44 F5.1 deg i [11.8/180] Inclination
46- 46 I1 --- Qual [0/9] Orbit grade from 1 (best) to 5 (tentative),
8 and 9 (astrometric)
48- 55 A8 --- Ref Reference code (see refs.dat)
57- 61 F5.1 deg Phi [0.3/174.1] Angle Phi between angular momenta
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Ref Reference code
10- 36 A27 --- Auth Author(s)' name(s)
38- 56 A19 --- BibCode Bibcode of the reference if any
58- 78 A21 --- Comm Comment
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 07-Mar-2018