Minor Planets and Dwarf Planets: Splinters and Survivors

2021 ◽  
pp. 33-66
Keyword(s):  
2019 ◽  
Vol 630 ◽  
pp. A68 ◽  
Author(s):  
Jian Li ◽  
Zhihong Jeff Xia ◽  
Liyong Zhou

Aims. We aim to determine the relative angle between the total angular momentum of the minor planets and that of the Sun-planets system, and to improve the orientation of the invariable plane of the solar system. Methods. By utilizing physical parameters available in public domain archives, we assigned reasonable masses to 718 041 minor planets throughout the solar system, including near-Earth objects, main belt asteroids, Jupiter trojans, trans-Neptunian objects, scattered-disk objects, and centaurs. Then we combined the orbital data to calibrate the angular momenta of these small bodies, and evaluated the specific contribution of the massive dwarf planets. The effects of uncertainties on the mass determination and the observational incompleteness were also estimated. Results. We determine the total angular momentum of the known minor planets to be 1.7817 × 1046 g cm2 s−1. The relative angle α between this vector and the total angular momentum of the Sun-planets system is calculated to be about 14.74°. By excluding the dwarf planets Eris, Pluto, and Haumea, which have peculiar angular momentum directions, the angle α drops sharply to 1.76°; a similar result applies to each individual minor planet group (e.g., trans-Neptunian objects). This suggests that, without these three most massive bodies, the plane perpendicular to the total angular momentum of the minor planets would be close to the invariable plane of the solar system. On the other hand, the inclusion of Eris, Haumea, and Makemake can produce a difference of 1254 mas in the inclination of the invariable plane, which is much larger than the difference of 9 mas induced by Ceres, Vesta, and Pallas as found previously. By taking into account the angular momentum contributions from all minor planets, including the unseen ones, the orientation improvement of the invariable plane is larger than 1000 mas in inclination with a 1σ error of ∼50−140 mas.


2021 ◽  
Author(s):  
Nick Sioulas

<p><strong>Photometric observations of the main-belt asteroid 665 Sabine and Minor Planet Bulletin</strong></p> <p> </p> <p>Nick Sioulas</p> <p>NOAK Observatory, Stavraki (IAU code L02) Ioannina, Greece ([email protected])</p> <p><strong>Introduction</strong></p> <p>In this work, the photometric observations of the main-belt asteroid 665 Sabine were conducted from the NOAK Observatory, in Greece in order to determine its synodic rotation period. The results were submitted to Asteroid Lightcurve Photometry Database (ALCDEF) and Minor Planet Bulletin.</p> <p><strong>Abstract</strong></p> <p>The Minor Planet Bulletin is the official publication of the Minor Planets Section of the Association of Lunar and Planetary Observers (ALPO). All amateurs and professionals can publish their asteroid photometry results, including lightcurves, H-G parameters, color indexes, and shape/spin axis models. It is also the refereed journal by the SAO/NASA ADS. All MPB papers are indexed in the ADS.</p> <p> </p> <p>The lightcurve of an asteroid can be used to determine the period, the shape and its size. We can also understand its composition (if it is a solid body or something else) and the orientation of the spin axes. Due to the high number of the asteroids the need of measuring them is important and all available telescopes are necessary to track them.</p> <p> </p> <p>My amateur observatory participates in the effort to record all these objects in the Solar System. It also conducts observations of various objects and other phenomena such as exoplanet transits, contributing to the Ariel Space Mission with the Exoclock Project, asteroid occultations and comet photometry.</p> <p>The observatory is registered in IAU as L02, «NOAK Observatory, Stavraki», in the town of Ioannina, Greece.</p> <p> </p> <p><strong>References</strong></p> <p>[1] Roger Dymock: Asteroids and Dwarf Planets</p> <p>[2] Brian D. Warner: A Practical Guide to Lightcurve Photometry and Analysis</p> <p>[3] http://alcdef.org/index.php</p> <p>[4] http://www.minorplanet.info/MPB/</p>


1966 ◽  
Vol 25 ◽  
pp. 197-222 ◽  
Author(s):  
P. J. Message

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.


1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.


1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.


1988 ◽  
Vol 128 ◽  
pp. 55-60
Author(s):  
Arthur L. Whipple ◽  
Raynor L. Duncombe ◽  
Paul D. Hemenway

We have begun a program to establish a dynamical reference frame based on the motions of minor planets. The program will utilize observations from the Hubble Space Telescope, and will ultimately tie the HIPPARCOS reference system to a dynamical base. Thirty-four minor planets, 20 of which are suitable for observation with the Hubble Space Telescope, have been selected. Ground based observations, particularly crossing-point observations with long focus reflectors, have been initiated.A computer program to simultaneously solve for the corrections of the orbits of the 34 minor planets including the crossing-point observations, was successfully run. The observations are treated by the method of W. H. Jeffreys. Using simulated data, solutions with and without crossing point observations demonstrate the value of those observations to produce a homogeneous and coherent set of results.


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