The origin of the solar system: Implications for transneptunian planets and the nature of the long-period comets

1978 ◽  
Vol 18 (2) ◽  
pp. 145-194 ◽  
Author(s):  
E. M. Drobyshevski
Keyword(s):  
2007 ◽  
Vol 3 (S248) ◽  
pp. 66-73
Author(s):  
J.-E. Arlot

AbstractThe main goal of the astrometry of solar system objects is to build dynamical models of their motions to understand their evolution, to determine physical parameters and to build accurate ephemerides for the preparation and the exploitation of space missions. For many objects, the ground-based observations are still very important because radar or observations from space probes are not available. More, the need of observations on a long period of time makes the ground-based observations necessary. The solar system objects have very different characteristics and the increase of the astrometric accuracy will depend on the objects and on their physical characteristics. The purpose of this communication is to show how to get the best astrometric accuracy.


2016 ◽  
Vol 12 (S325) ◽  
pp. 263-265
Author(s):  
Rustam Guliyev ◽  
Ayyub Guliyev

AbstractIn the present work we investigate the possible relationship of long-period comets with five large and distant trans-Neptunian bodies (Sedna, Eris, 2007 OR10, 2012 VP113and 2008 ST291) in order to determine the probability of the transfer of a part of these kind of comets to the inner of the Solar System. To identify such relationships, we studied the relative positions of the comet orbits and listed TNOs. Using numerical integration methods, we examined dynamical evolution of the comets and have found one encounter of comet C/1861J1 and Eris.


2020 ◽  
Author(s):  
Youssef Moulane ◽  
Emmanuel Jehin ◽  
Francisco José Pozuelos ◽  
Jean Manfroid ◽  
Zouhair Benkhaldoun ◽  
...  

<p>Long Period Comets (LPCs) have orbital periods longer than 200 years, perturbed from their resting place in the Oort cloud. Such gravitational influences may send these icy bodies on a path towards the center of the Solar system in highly elliptical orbits. In this work, we present the activity and composition evolution of several LPCs observed with both TRAPPIST telescopes (TS and TN) during the period of 2019-2020. These comets include: C/2017 T2 (PANSTARRS), C/2018 Y1 (Iwamoto), C/2018 W2 (Africano), and disintegrated comet C/2019 Y4 (ATLAS). We monitored the OH, NH, CN, C<sub>2</sub> and C<sub>3</sub> production rates evolution and their chemical mixing ratios with respect to their distances to the Sun as well as the dust production rate proxy (A(0)fp) during the journey of these comets into the inner Solar system.</p> <p><strong>C/2017 T2 (PANSTARRS)</strong> is a very bright comet which was discovered on October 2, 2017 when it was 9.20 au from the Sun. We started observing this comet with TS at the beginning of August 2019 when it was at 3.70 au. The comet made the closest approach to the Earth on December 28, 2019 at a distance of 1.52 au and it passed the perihelion on May 4, 2020 at 1.61 au. The water production rate of the comet reached a maximum of (4,27±0,12)10<sup>28 </sup>molecules/s and its dust production rate (A(0)fp(RC)) also reached the peak of 5110±25 cm on January 26, 2020, when the comet was at 2.08 au from the Sun (-100 days pre-perihelion). At the time of writing, we still monitoring the activity of the comet with TN at heliocentric distance of 1.70 au. Our observations show that C/2017 T2 is a normal LPC.</p> <p><strong>C/2018 Y1 (Iwamoto)</strong> is a nearly parabolic comet with a retrograde orbit discovered on December 18, 2018 by Japanese amateur astronomer Masayuki Iwamoto. We monitored the activity and composition of Iwamoto with both TN and TS telescopes from January to March 2019. The comet reached its maximum activity on January 29, 2019 when it was at 1.29 au from the Sun (-8 days pre-perihelion) with Q(H<sub>2</sub>O)=(1,68±0,05)10<sup>28 </sup>molecules/s and A(0)fp(RC)= 92±5 cm. These measurements show that it was a dust-poor comet compared to the typical LPCs.</p> <p><strong>C/2018 W2 (Africano) </strong>was discovered on November 27, 2018 at Mount Lemmon Survey with a visual magnitude of 20. The comet reached its perihelion on September 6, 2019 when it was at 1.45 au from the Sun. We monitored the comet from July 2019 (r<sub>h</sub>=1.71 au) to January 2020 (r<sub>h</sub>=2.18 au) with both TN and TS telescopes. The comet reached its maximum activity on September 21, 15 days post-perihelion (r<sub>h</sub>=1.47 au) with Q(H<sub>2</sub>O)=(0,40±0,03)10<sup>28 </sup>molecules/s.</p> <p><strong>C/2019 Y4 (ATLAS)</strong> is a comet with a nearly parabolic orbit discovered on December 18, 2019 by the ATLAS survey. We started to follow its activity and composition with broad- and narrow-band filters with the TN telescope on February 22, 2019 when it was at 1.32 au from the Sun until May 3, 2020 when the comet was at a heliocentric distance of 0.90 au inbound. The comet activity reached a maximum on March 22 (r<sub>h</sub>=1.65 au) 70 days before perihelion. At that time, the water-production rate reached (1,53±0,04)10<sup>28 </sup>molecules/s and the A(0)fp reached (1096±14) cm in the red filter. After that, the comet began to fade and disintegrated into several fragments.</p>


1996 ◽  
Vol 172 ◽  
pp. 209-212 ◽  
Author(s):  
J.Q. Zheng ◽  
M.J. Valtonen ◽  
S. Mikkola ◽  
H. Rickman

Investigators generally conjecture a steady flux of new comets from the Oort cloud through the inner Solar system. Due to gravitational perturbations by major planets these objects may escape, become long period comets (LPCs) if their orbital periods P are larger than 200yr or become short period comets (SPCs) when their period is less than 200yr. SPCs are further divided in two types: the Halley type comets (HT, for P > 20yr) and the Jupiter family comets (JF, for P < 20yr).


1985 ◽  
Vol 83 ◽  
pp. 31-41
Author(s):  
W.M. Napier

AbstractThe effects of encounters with massive nebulae on the long-period comet population are examined, paying particular attention to the uncertainties in the data. An earlier conclusion, that the long-period comet system is dynamically unstable, is upheld. Whether replenishment by unbinding from a dense inner comet cloud is a viable hypothesis awaits detailed modelling, but a qualitative discussion is given which argues tentatively against it. If comets occur in molecular clouds, however, their capture into temporarily bound Solar System orbits is a natural consequence of close encounters for realistic velocities and potentials. A large disturbance or capture may have occurred a few Myr ago as the Sun emerged from the Orion spiral arm.


1998 ◽  
Vol 11 (1) ◽  
pp. 223-228
Author(s):  
R. Malhotra

Ideas about the contents of the Solar System beyond Neptune and Pluto can be traced back to at least Edgeworth (1943, 1949) and Kuiper (1951), who speculated on the existence of pre-planetary small bodies in the outer Solar System beyond the orbit of Neptune - remnants of the accretion process in the primordial Solar Nebula. The basis for the speculation was primarily the argument that the Solar Nebula was unlikely to have been abruptly truncated at the orbit of Neptune, and that in the trans-Neptunian accretion timescales were too long for bodies larger than about ˜ 1000 km in radius to have formed in the 4.5 billion year age of the Solar System. Another important theoretical argument relevant to this region of the Solar System is related to the origin of short period comets. Fernández (1980) suggested that the short period comets may have an origin in a disk of small bodies beyond Neptune, rather than being “captured” from the population of long period comets originating in the Oort Cloud, the latter scenario having considerable difficulty reconciling the observed flux of short period comets with the exceedingly low efficiency of transfer of long period comet orbits to short period ones by means of the gravitational perturbations of the giant planets. The new scenario received further strength in the numerical work of Duncan et al. (1988) and Quinn et al. (1990) which showed that the relatively small orbital inclinations of the Jupiter-family short period comets were not consistent with a source in the isotropic Oort Cloud of comets but could be reproduced with a source in a low-inclination reservoir beyond Neptune’s orbit. Duncan et al. named this hypothetical source the Kuiper Belt, and the name has come into common use in the last decade (although other names are also in use, e.g. Edgeworth-Kuiper Belt, and trans-Neptunian objects). A recent theoretical milestone was the work by Holman and Wisdom (1993) and Levison and Duncan (1993) on the long term stability of test particle orbits in the trans-Neptunian Solar System. This work showed that low-eccentricity, low-inclination orbits with semimajor axes in excess of about 43 AU are stable on billion year timescales, but that in the region between 35 AU and 43 AU orbital stability times range from 107 yr to more than 109 yr [see, for example, figure 1 in Holman (1995)]. Orbital instability in this intermediate region typically leads to a close encounter with Neptune which causes dramatic orbital changes, with the potential for subsequent transfer to the inner Solar System. Thus, this region could in principle serve as the reservoir of short period comets at the present epoch. However, the idea of a kinematically cold — i.e. low-eccentricity, low-inclination — population in this region is at odds with recent observations, and the question of the origin of short period comets remains unsettled at the present time.


1985 ◽  
Vol 83 ◽  
pp. 129-142
Author(s):  
David W. Hughes

It has long been realised that Jovian perturbation is the dominant cause of the transition of long period comets (Period > 200 yr) into short period ones (P < 200 yr). When the differences in the detectability of comets in the two groups are taken into account it is clear that the present day flux of long period comets is sufficient to provide the present collection of short period comets in the inner solar system.The fact that meteoroid streams are produced by decaying short period comets was first recognised around 1866 (see Hughes 1982a). The magnificent display of Leonids in that year enabled the radiant position and time of maximum rate to be easily calculated. Assuming the orbital period to be 33.25 yr Le Verrier (1867) and Schiaparelli (1867) published orbits for the meteoroid stream. The orbit of comet 1866 I, which had been discovered by Guillaume Tempel, from Marseilles on December 19, 1865 and independently by Horace P. Tuttle from Harvard, Massachusetts on January 5, 1866, has been calculated and published by Oppolzer (1867a). Almost to a man Peters (1867), Schiaparelli (1867) and Oppolzer (1867b) realised that the comet and the stream had similar orbits. Since that time many more examples have been put forward, two famous ones being the Perseids and comet Swift-Tuttle (1862 III) and the Eta Aquarids and Orionids both of which have comet Halley (1910 II) as their parent. For more details see Cook (1973).


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