J/AJ/154/62 Orbital parameters of Kuiper Belt objects (Volk+, 2017)
The curiously warped mean plane of the Kuiper Belt.
Volk K., Malhotra R.
<Astron. J., 154, 62-62 (2017)>
=2017AJ....154...62V 2017AJ....154...62V (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets
Keywords: celestial mechanics - Kuiper belt: general
Abstract:
We measured the mean plane of the Kuiper Belt as a function of
semimajor axis. For the classical Kuiper Belt as a whole (the
nonresonant objects in the semimajor axis range 42-48au), we find a
mean plane of inclination im=1.8°-0.4°+0.7° and
longitude of ascending node Ωm=77°-14°+18° (in
the J2000 ecliptic-equinox coordinate system), in accord with
theoretical expectations of the secular effects of the known planets.
With finer semimajor axis bins, we detect a statistically significant
warp in the mean plane near semimajor axes 40-42au. Linear secular
theory predicts a warp near this location due to the ν18 nodal
secular resonance; however, the measured mean plane for the 40.3-42au
semimajor axis bin (just outside the ν18) is inclined ∼13° to
the predicted plane, a nearly 3σ discrepancy. For the more
distant Kuiper Belt objects of semimajor axes in the range 50-80au,
the expected mean plane is close to the invariable plane of the solar
system, but the measured mean plane deviates greatly from this: it has
inclination im=9.1°-3.8°+6.6° and longitude of
ascending node Ωm=227°-44°+18°. We estimate
this deviation from the expected mean plane to be statistically
significant at the ∼97%-99% confidence level. We discuss several
possible explanations for this deviation, including the possibility
that a relatively close-in (a≲100au), unseen, small planetary-mass
object in the outer solar system is responsible for the warping.
Description:
Our starting point is the list of minor planets in the outer solar
system cataloged in the database of the Minor Planet Center
(http://www.minorplanetcenter.net/iau/lists/t_centaurs.html and
http://www.minorplanetcenter.net/iau/lists/t_tnos.html) as of 2016
October 20.
The complete listing of our sample, including best-fit orbital
parameters and sky locations, is provided in Table1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 108 906 List objects used to calculate mean planes
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
http://www.minorplanetcenter.net/ : Minor Planet Center
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- MPC Minor Planet Center designation (1)
9- 19 E11.5 AU a [36.3/149.85] Best-fit barycentric semi-major
axis (2)
21- 29 E9.3 AU e_a [0.0005/4.14] The 1-σ uncertainty in a
(da) (3)
31- 41 E11.5 --- e [0.0018/0.76] Best-fit eccentricity (2)
43- 53 E11.5 rad i [0.0018/0.88] Best-fit inclination (2)
55- 65 E11.5 rad Omega [0.0022/6.28] Best-fit longitude of ascending
node (Ω) (2)
67- 77 E11.5 rad omega [0.0014/6.27] Best-fit argument of perihelion
(ω) (2)
79- 84 F6.3 rad lambda [-3.14/3.14] Ecliptic longitude (λ) (2)
86- 91 F6.3 rad beta [-0.844/0.805] Ecliptic latitude (β) (2)
93- 98 F6.3 AU Dist [31.544/96.255] Heliocentric distance (rh)
100-108 F9.1 d Epoch Epoch of the orbit fit and sky position
(in Julian Date)
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Note (1): The MPC designations are given in their packed format (see
http://www.minorplanetcenter.net/iau/info/PackedDes.html).
Note (2): The orbital elements are the best-fit barycentric elements from a
Bernstein & Khushalani (2000AJ....120.3323B 2000AJ....120.3323B) orbit fit to the astrometry
available for each object from the Minor Planet Center (MPC). All elements
are referenced to the J2000 ecliptic coordinate system.
Note (3): Taken from the orbit-fit covariance matrix.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 07-Nov-2017