Covering of cometary nucleus by refractory crust and its evolution into asteroid-like body

1999 ◽  
Vol 173 ◽  
pp. 365-370
Author(s):  
Kh.I. Ibadinov
Keyword(s):  
Laboratory Experiments ◽  
Cometary Nucleus ◽  
Sublimation Rate ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Brightness Decrease ◽  
Crust Thickness ◽  
Ice Sublimation ◽  
Period Comet

AbstractFrom the established dependence of the brightness decrease of a short-period comet dependence on the perihelion distance of its orbit it follows that part of the surface of these cometary nuclei gradually covers by a refractory crust. The results of cometary nucleus simulation show that at constant insolation energy the crust thickness is proportional to the square root of the insolation time and the ice sublimation rate is inversely proportional to the crust thickness. From laboratory experiments resulted the thermal regime, the gas productivity of the nucleus, covering of the nucleus by the crust, and the tempo of evolution of a short-period comet into the asteroid-like body studied.

scholarly journals The Kuiper Belt

1994 ◽  
Vol 160 ◽  
pp. 31-44
Author(s):  
Jane Luu
Keyword(s):  
Solar System ◽  
Kuiper Belt ◽  
Cometary Nucleus ◽  
Outer Solar System ◽  
Short Period Comet ◽  
Short Period ◽  
Lower Limits ◽  
Period Comet

The existence of a belt of comets in the outer solar system (the “Kuiper belt”) has been postulated for a variety of reasons, including the need for a source for the short-period comets. The existence of the belt seems supported by the discoveries of the trans-Neptunian objects 1992 QB1, 1993 FW, 1993 RO, 1993 RP, 1993 SB, and 1993 SC. If these objects are members of the Kuiper belt, crude lower limits on the belt population can be established from the discoveries. The Kuiper belt comets are likely to be primordial remnants of the disk from which the solar system accreted. According to the current theories of cometary nucleus evolution, these objects are expected to possess mantles (“irradiation mantles”) which are different from mantles of comets which have been heated to the point of sublimation (“rubble mantles”). Kuiper belt comets on their way to short-period comet orbits may exist among the Centaur objects.

scholarly journals A Core-Mantle Model for Cometary Nuclei and Asteroids of Possible Cometary Origin

1971 ◽  
Vol 12 ◽  
pp. 423-428 ◽  
Author(s):  
Zdenek Sekanina
Keyword(s):  
Dynamical Behavior ◽  
Physical Appearance ◽  
Minor Planets ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Long Time ◽  
Cometary Origin ◽  
Period Comet

Arguments for a long time have been brought forward in support of the idea that the minor planets with orbits approaching Earth's orbit might be of cometary origin. Our feeling is that before such hypotheses are considered for any particular object, it is necessary to prove that differences in physical appearance and dynamical behavior between a typical asteroid of the Apollo or Albert types and a typical short-period comet can be interpreted in terms of cometary evolution.In this paper, we discuss models of cometary nuclei, transition of an object from cometary phase into asteroidal phase, and specific asteroidal objects that may be of cometary origin.

scholarly journals The Thermal History and Structure of Cometary Nuclei

1991 ◽  
Vol 116 (2) ◽  
pp. 733-760 ◽  
Author(s):  
Hans Rickman
Keyword(s):  
Structural Changes ◽  
Solar Nebula ◽  
Thermal Evolution ◽  
Bulk Composition ◽  
Radioactive Decay ◽  
Internal Heating ◽  
Cometary Nuclei ◽  
Short Period Comet ◽  
Short Period ◽  
Period Comet

Abstract.Cometary nuclei are often considered to be the most primitive bodies of the solar system. Thus it is particularly important to find out what structural changes may have been brought about as a result of their thermal evolution. Is there reason to believe that the bulk composition of the nucleus of a present-day short-period comet may differ from that of the original planetesimal in the solar nebula? Apart from the development of a non-volatile surface layer (‘dust mantle’), what further depth-dependent differentiation can we expect in such a nucleus? These are the ultimate questions addressed in this paper, and attention is focused on the two most active stages of thermal evolution: the early planetesimal stage with internal heating basically due to radioactive decay, and the recent or present cometary phase with strong external heating due to insolation of the surface.

Models of comets with strongly variable nongravitational effects

1999 ◽  
Vol 173 ◽  
pp. 381-387
Author(s):  
M. Królikowska ◽  
G. Sitarski ◽  
S. Szutowicz
Keyword(s):  
Cometary Nucleus ◽  
Spin Axis ◽  
Reactive Force ◽  
Orbital Elements ◽  
Cometary Nuclei ◽  
Short Period ◽  
Basic Parameters ◽  
Polar Radius ◽  
Cometary Activity ◽  
Nongravitational Effects

AbstractThe nongravitational motion of five “erratic” short-period comets is studied on the basis of published astrometric observations. We present the precession models which successfully link all the observed apparitions of the comets: 21P/Giacobini-Zinner, 31P/Schwassmann-Wachmann 2, 32P/Comas Solá, 37P/Forbes, and 43P/Wolf-Harrington. We used the Sekanina's forced precession model of the rotating cometary nucleus to include the nongravitational terms into equations of the comet's motion. Values of six basic parameters (four connected with the rotating comet nucleus and two describing the precession of spin-axis of the nucleus) have been determined along the orbital elements from positional observations of the comets. The solutions were derived with additional assumptions which introduce instantaneous changes of modulus of reactive force,Aand of maximum of cometary activity with respect to perihelion time. The present precession models impose some contraints on sizes and rotational periods of cometary nuclei. According to our solutions the nucleus of 21P/Giacobini-Zinner with oblateness along the spin-axis of about 0.32 (equatorial to polar radius of 1.46) is the most oblate among five investigated comets.

Some comments about observations and image processing of comet 29P/Schwassmann-Wachmann 1

1999 ◽  
Vol 173 ◽  
pp. 243-248
Author(s):  
D. Kubáček ◽  
A. Galád ◽  
A. Pravda
Keyword(s):  
Image Processing ◽  
Large Scale ◽  
Harvard College ◽  
Oak Ridge ◽  
Large Scale Structures ◽  
Short Period Comet ◽  
Short Period ◽  
Scale Structures ◽  
Harvard College Observatory ◽  
Period Comet

AbstractUnusual short-period comet 29P/Schwassmann-Wachmann 1 inspired many observers to explain its unpredictable outbursts. In this paper large scale structures and features from the inner part of the coma in time periods around outbursts are studied. CCD images were taken at Whipple Observatory, Mt. Hopkins, in 1989 and at Astronomical Observatory, Modra, from 1995 to 1998. Photographic plates of the comet were taken at Harvard College Observatory, Oak Ridge, from 1974 to 1982. The latter were digitized at first to apply the same techniques of image processing for optimizing the visibility of features in the coma during outbursts. Outbursts and coma structures show various shapes.

scholarly journals Physical Observations of the Short-Period Comet 1969 IV

1972 ◽  
Vol 45 ◽  
pp. 27-34
Author(s):  
K. I. Churyumov ◽  
S. I. Gerasimenko
Keyword(s):  
Spectral Region ◽  
Sunspot Area ◽  
Radius Vector ◽  
Short Period Comet ◽  
Short Period ◽  
Single Emission ◽  
The Continuum ◽  
Period Comet

The new short-period comet Churyumov-Gerasimenko, discovered by the authors on plates taken by the Kiev University cometary expedition to Alma-Ata in September 1969, was systematically photographed with fast telescopes at Byurakan and Alma-Ata until March 1970. Measurements were made of the photographic magnitude of the photometric nucleus, as well as of the photographic and photovisual integral magnitudes. The variations in nuclear magnitude were found to be well correlated with changes in the total sunspot area. The integral photometric parameters are Hy = 11.91±0m.54 and n=4.0±0.8 (in the photographic spectral region). Deviations of the tail axis from the prolonged radius vector were considerable. A spectrogram shows the continuum and emission of CN, C2 and C3 in the head, the continuum and a single emission (perhaps CO+) in the tail.

scholarly journals Detection of a Long-Extended Dust Trail Associated with Short-Period Comet 4P/Faye in 2006 Return

2007 ◽  
Vol 59 (4) ◽  
pp. L25-L28 ◽  
Author(s):  
Yuki Sarugaku ◽  
Masateru Ishiguro ◽  
Jeonghyun Pyo ◽  
Naoya Miura ◽  
Yoshikazu Nakada ◽  
...  
Keyword(s):  
Dust Trail ◽  
Short Period Comet ◽  
Short Period ◽  
Period Comet
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