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7604 Kridsadaporn

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Kridsadaporn
Discovery
Discovered byR. H. McNaught
Discovery siteSiding Spring
Discovery dateAugust 31, 1995
Designations
7604
1995 QY2
Orbital characteristics
Epoch May 14, 2008
Aphelion4.8999326
Perihelion1.3269598
Eccentricity0.5737971
2006.5984761
86.60984
Inclination20.45084
147.29929
266.24561
Physical characteristics
13.7

Kridsadaporn (Template:Pron-en is a Mars-crossing asteroid discovered by R. H. McNaught on 15 August 1994 at Siding Spring Observatory. Its high orbital eccentricity of just over 0.574[1] places it within a group of objects known as Asteroid in Cometary Orbit - (ACO's).[2][3] With its notable orbital parameters, Kridsadaporn is listed with the IAU Minor Planets Center as an Unusual Minor Planet.[4]

Discovery and naming

Discovered using the 0.5-m Uppsala Schmidt Telescope, used during the Siding Spring Survey (SSS) and as part of a broader network of Near-Earth object search programs,[5] Kridsadaporn was initially assigned the provisional designation 1995 QY2. Later in April 2005, it was renamed by its discoverer[6] in honor of Kridsadaporn Ritsmitchai, a then recently deceased friend who was also a member of staff[7] of the Research School of Astronomy and Astrophysics at the Australian National University and who worked and resided at Siding Spring Observatory.


Kridsadaporn, (กฤษฏาพร, กฤษดาพร) a Thai name comprising two words; "kridsada" (กฤษฏา) of Sanskrit origin, sometimes Romanized as gritsada, kritsada and often kruetsada however, Thai script rules[8] for Sanskrit borrow-words vowels transcribe it as "krisada", (กฤษดา) while retaining the original meaning associated with "kridsada" (กฤษฏา) [supernatural powers, divine, celestial], and, "porn" (พร) [blessing, benediction, favor] and when used with Thai first names is meant as, "a blessing from the Buddha" for both, the gift of a child, and, the favor of particular attributes, referred to within the name, manifesting within the child.[9] Many Thai first names are suffixed with พร pronounced as "phaawn", transliterated using the Royal Thai General System as "phon"[10] however, variations in translation methods sometimes result in it being Romanized as "pon"[11] - in which case an "r" is often added for a truer phonetic approximation. In Thai tradition, a child's name is chosen using complex Buddhist name giving rituals where Thai astrology is widely used, often in consultation with a Buddhist monk.[9][12] Parents of a newly-born child named Kridsadaporn (กฤษฏาพร) may believe, or may accept, the name's meaning as;

"A blessing from the Buddha; a child, gifted with divine qualities and supernatural powers".

History

An approximation know as the Tisserand criteria (T) is applied to cometary encounters with planets (such a Jupiter) and used to describe their orbital inter-relationship.[13] Asteroidal-appearing bodies in elliptical orbits with jovian Tisserand parameter Tj < 3 have only begun to appear in search programs since the mid 1980’s - Kridsadaporn's jovian Tisserand parameter is Tj = 2.858.[1] Before this, the failure to identify these objects was used as an argument against the existence of extinct cometary nuclei. Over the past two decades, an increasing number of asteroids, based upon their orbital and physical characteristics have been suggested as extinct or dormant comets candidates. It is now considered likely that within the asteroid population there exist a significant number of dormant or extinct comets.[14]


More recently, Kridsadaporn has received closer attention having been included in a number of studies relating to the analysis of spectral properties of asteroids in cometary orbits (ACO);[3][15] and, collisional activation processes, and the dynamic and physical properties of ACO’s.[2][16] The investigation of ACO's is considered important in the understanding of formation processes of cometary dust mantles and the end states of comets, so as to determine the population of Jupiter family comets (JFC's), and, to also understand the dynamical processes involved in the transport mechanism of asteroids from typical asteroidal orbits to cometary-like ones.[3]


In earlier studies, ACO's have sometimes been referred to as cometary asteroids or comet-asteroid transition objects.[16]

Orbit

Kridsadaporn's highly ellipical orbit has similar orbital characteristics as those of the Jupiter-family comets (JFC) which populate the jovian Tisserand invarient range 2 ≤ Tj ≤ 3 supporting the scenario that a significant number of asteriods in cometary orbits being extinct or dormant cometary candidates.[2]

Mars-crossing orbit

Kridsadaporn is amongst another group of bodies [Mars-crossing (MC) and/or near-Earth object (NEO) populations] that may have originated from the main asteroid belt as fragments injected into a mean-motion resonance or secular resonance, developing increasingly higher orbital eccentricity over time resulting in the perihelion distance to become smaller than the aphelion distances of the inner planets. At their birth, near-earth asteroids (NEA) and MC orbits are in resonance, and when their orbital eccentricity becomes large enough to the point that their orbits cross those of the inner planets, their orbits then become modified in a random-walk fashion. This results in a complex interplay between planetary encounters and resonances which may lead to a range of unexpected outcomes including cometary-type orbits; solar collisions; or, eventual ejection from the Solar System.[17][16]

Fig. 1 - depicting the most prominant of Kirkwood gaps, corresponding to locations of orbital resonances with Jupiter

Orbital evolution

Detailed investigations into Kridsadaporn’s dynamic evolution have been carried out by creating 15 “clone” orbits, integrated forward over a period of 1.2 × 106
 years, by changing the last digit of it orbital parameters. Nine (9) clones demonstrated moderate chaotic behavior jumping between the jovian mean-motion resonances of 15:7, 9:4, and 11:5 with some orbits becoming Earth-crossers within the integration period. The remaining six (6) clones grew in orbital eccentricity until becoming Jupiter-crossers, and then, behaving as Jupiter-family comets, were ejected from the Solar System over periods in the order of 105
 years.[16]


The histogram in Figure 1 depict dips in the distribution of main belt asteroids with semi-major axis. These gaps are more sparingly populated with objects of higher orbital eccentricity. Known as Kirkwood gaps, these dips in distribution density correspond to the location of obital resonances with Jupiter. Objects with eccentric orbits continue to increase in orbital eccentricity over longer timescales to eventually break out of resonance due to close encounters with a major planet.[18] Kridsadaporn, with a semi-major axis e = 3.110626[1] corresponds with a very narrow gap associated with 11:7 resonance[16] (less obviously depicted in Fig. 1) within a series of weaker and less sculped gaps.

Physical characteristics

Kridsadaporn is of a C-type taxonomic classification[3] typified as dark carbonaceous objects.[19]

A number of studies[3][15] included Kridsadaporn within a sample of asteroids in cometary orbits in order to understand the relationships in spectral characteristics between ACO’s; the Jupiter-family comets; and, the outer main belt asteroids. The only secure data yielded was that comets present neutral or red feature-less spectra.[3] Earlier studies[20] suggested that comets in all stages of evolution - active; dormant; and, dead - as being very dark often reddish objects with spectra similar to D-type, P-type ,and C-type asteroids of the outer Solar System with probably carbonaceous dust containing reddish organic compounds controlling their color and albedos characteristics.[3]

Origins of ACO objects

Studies analyzing the albedo distribution of a sample of asteroids in cometary orbits,[21] found in general that they exhibit a lower albedos than objects with Tj > 3 and further concluded that all ACO’s in that sample with Tj < 2.6 had albedo pV < 0.075 - similar to those measured for cometary nuclei - suggesting cometary origins. [3]


A sample of objects, which included Kridsadaporn, was used in a study[3] of the relationship between jovian Tisserand invariant and spectral properties of asteroids in cometary orbits and which determined that all observed ACO's within the sample with Tj < 2.9 were feature-less. Kridsadaporn with its jovian Tisserand invariant of 2.858 [1] falls within the feature-less (without bands) comet-like spectral group. These studies also concluded that ACO’s with featured spectra (with bands) typical of the main belt had Tj ≥ 2.9 while those with Tj < 2.9 demonstrated comet-like spectra, suggesting that the subsample of ACO’s with 2.9 ≤ Tj ≤ 3.0 could be populated by a large fraction of interlopers from the inner part of the belt.[2]


Kridsadaporn has a perihelion distance of q = 1.3224 AU.[1] A study of the relationship between the size distribution profile and perihelion distances of ACO's[22] concluded that a sub-sample of ACO's with a perihelion distance q > 1.3 AU had a size distribution profile similar to that of the Jupiter family comets, suggesting that subsample to be composed of a significant fraction of dormant comets, while a large fraction of ACO's with q < 1.3 AU could more likely be scattered objects from the outer main belt.[2]


Objects with a jovian Tisserand invariant Tj ≤ 3 and taxonomic properties consistent with a low albedo, however, is not enough to imply that they are dormant or extinct comets. The fraction of low albedo, Tj ≤ 3 objects actually being dormant or extinct comets, is estimated to be 65% ± 10%[15]

References

  1. ^ a b c d e "JPL Small-body browser - 7604 Kridsadaporn". Jet Propulsion Laboratory.
  2. ^ a b c d e Díaz, C. G. (2008). "Collisional activatin of asteroids in cometary orbits". A&A. 487: 363–367. doi:10.1051/0004-6361:20079236. Retrieved 2011-03-29. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  3. ^ a b c d e f g h i Licandro, J. (2008). "Spectral properties of asteroids in cometary orbits" (PDF). A&A. 481: 861–877. doi:10.1051/0004-6361:20078340. Retrieved 2011-03-29. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  4. ^ "List of Unusual Minor Planets". IAU Minor Planets Center.
  5. ^ Stokes, Grant H.; Evans, Jenifer B.; Larson, Stephen M. (2002). "Near-Earth Asteroid Search Programs". Asteroids III. Tucson: University of Arizona Press. pp. 45–54. Bibcode:2002aste.conf...45S. Retrieved 2011-04-20.
  6. ^ "Naming Astronomical Objects". International Astronomy Union. Retrieved 2011-04-01.
  7. ^ "Annual Report, staff list" (PDF). Research School of Astronomy and Astrophysics, Australian National University. 2003. p. 21. Retrieved 2011-04-01.
  8. ^ "Extended Definition: Thai alphabet". Webster's Online Dictionary. Retrieved 2011-04-02.
  9. ^ a b Snae, Chakkrit. "Constructing a Rule Based Naming System for Thai Names Using the Concept of Ontologies" (PDF). Naresuan University Phitsanulok, Thailand. Retrieved 2010-04-02.
  10. ^ "Internet resource for the Thai language". Thai-language.com. Retrieved 2010-04-02.
  11. ^ "Thai<>English Dictionary". thai2english.com. Retrieved 2011-04-02.
  12. ^ *Blessings of the Three Jewels "Baby blessing ceremony". Religion.answers.wikia.com. Retrieved 2011-04-02. {{cite web}}: Check |url= value (help)*de Young, John E. (1958), Village life in modern Thailand, University of California Press, p. 53
  13. ^ Brant, John C.; Chapman, Robert D. (2004), Introduction to asteroids, Cambridge University Press, p. 69, ISBN 0-521-00466-7
  14. ^ Weissmen, Paul R. (1998), IN: Asteroids II; Proceedings of the Conference, Tucson, AZ, Mar. 8-11, 1988 (A90-27001 10-91), University of Arizona Press: 880–920, Bibcode:1989aste.conf..880W http://adsabs.harvard.edu/abs/1989aste.conf..880W, retrieved 2011-04-12 {{citation}}: Missing or empty |title= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |name= ignored (help)
  15. ^ a b c Binzel, Richard P. (2004). "Observed spectral properties on near-Earth objects:results for population distribution, source regions, and space weathering processes" (PDF). Icarus. 70: 259–294. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  16. ^ a b c d e di Martino, M. (1998). "Dynamic and physical properties of comet-asteroid transition objects". Astronomy and Astrophysics. 329. The Smithsonian/NASA Astrophysics Data System: 1145–1151. Bibcode:1998A&A...329.1145D. Retrieved 2011-04-12. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  17. ^ Froeschle, C. (1995), "Secular resonances and the Dynamics of Mars-crossing and near-Earth asteroids", Icarus, 117 (1), ScienceDirect: 45–61, doi:10.1006/icar.1995.1141, retrieved 2011-04-12 {{citation}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  18. ^ Tsiganis, Kleomenis (March 29, 2002). "Stable Chaos versus Kirkwood Gaps in the Asteroid Belt: A Comparative Study of Mean Motion Resonances" (pdf). Icarus. pp. 284–299. doi:10.1006/icar.2002.6927. Retrieved April 20, 2011. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  19. ^ Chodas, Paul. "Introduction to Comets and Asteroids" (PDF). JPL/Caltec. Retrieved 2011-04-12.
  20. ^ Hartmann, William K. (June 19, 1986). "The relationship of active comets, "extinct" comets, and dark asteroids". Icarus. pp. 33–50. doi:10.1016/0019-1035(87)90005-4. Retrieved 2011-04-12. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  21. ^ Fernández, Yanga R. (2005). "Albedos of asteroids in comet-like orbits". The Astronomical Journal. 130: 308. doi:10.1086/430802. Retrieved 2011-04-12. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  22. ^ Alvarez-Candel, A.; Licandro, J. (2006). "The size distribution of asteroids in cometary orbits and related populations". Astronomy and Astrophysics. 458 (3): 1007–1011. doi:10.1051/0004-6361:20064971. Retrieved 2011-04-12.

See also

External links

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