2005A&A...437.1093N -
Astronomy and Astrophysics, volume 437, 1093-1108 (2005/7-3)
Some characteristics of the outer Oort cloud as inferred from observations of new comets.
NESLUSAN L. and JAKUBIK M.
Abstract (from CDS):
We study the outer Oort cloud (OC) by numerical integration of 126600 orbits of hypothetical comets representing this cometary reservoir. We determine the distribution of the semi-major axis a for 4.6≲log(a)≲5, and estimate its population and total mass, as well as some other characteristics. The distribution of the semi-major axis is found initially by assuming a constant log(a) distribution and then identifying the theoretically predicted log(a) distribution of new comets with their observed log(a) distribution. The semi-major axis of outer-OC comets ranges from log(a)≃4.35 to typically log(a)≃5 on the decadic-logarithm scale. The relative distribution of this element can, however, be roughly determined only for log(a)≳4.55: dN∝a–sda, where 0.6≲s≲0.8. The perihelion distribution of new comets with log(a)≲4.55 is not constant in the zone of visibility (ZV) and a bias due to the observational selection cannot be eliminated. The lower limit of the outer OC population is 1x1011 to 2x1011. The currently available cometary data do not allow us to give a more exact lower estimate or an average estimate of the population. The OC has also been depleted by the combined Galactic-tide-planetary (GTP) perturbation with a local maximum rate at log(a)≃4.5. The ratio of these comets that are lost from the outer OC and of new comets that enter into the ZV in the same time frame is ≃2.5. The distributions of the angular elements of new comets at their previous perihelion passage are used to evaluate the correctness of our model of the outer OC. Specifically, we calculated the root of mean squares between the corresponding theoretical and observed distributions of ω, Ω, and cos (i) resulting in 2-5% unexplained residua.
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Journal keyword(s):
comets: general - Oort cloud - planets and satellites: formation
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ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
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[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
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Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
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17 42 28.87566 -28 59 12.3570
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Syntax of coordinates is : "ra dec (wtype) [error ellipse] quality bibcode" :
ra dec : right ascension and declination (unit and frame defined according to your Output Options)
Grey values are increasing the original precision due to the computation of frame transformations
(wtype) : wavelength class for the origin of the coordinates (Rad, mm, IR, Optical, UV, Xray, Gam)
[error ellipse] : measurement uncertainty, on (ra,dec) if the positional angle is 90 degrees, on (majaxis,minaxis) otherwise (in mas at defined epoch in the original catalogue),
position angle (in degrees North celestial pole to East)
References (12009 between 1850 and 2021) (Total 12009)
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