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{{short description|Trough system on Vesta}} |
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'''Divalia Fossa'''<ref>[http://planetarynames.wr.usgs.gov/Feature/14911;jsessionid=604BAC015C7EA07436F700D1435D1EDB IAU/USGS]</ref> {{IPA-en|dɨˈveɪliə ˈfɒsə|}} is the largest of the series of parallel [[Rheasilvia]]n equatorial troughs on the giant asteroid [[4 Vesta]]. It is approximately 10 km wide (estimated 22 km at its widest point) and encircles "most" of Vesta's equator,<ref>[http://dawn.jpl.nasa.gov/multimedia/imageoftheday/image.asp?date=20120711]</ref> or for at least 465 km. It is thought to be a compression fractures resulting from the impact that created Rheasilvia crater. It is one of the [[List of largest rifts and valleys in the Solar System|longer chasms in the Solar System]], and is named after the Roman festival of [[Divalia]]. |
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{{Use dmy dates|date=May 2024}} |
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{{Infobox feature on celestial object |
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|name = Divalia Fossae |
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|image = AV-L-17 Domna Quadrangle of Vesta.png |
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|caption = A section of Divalia Fossae between 45°E and 90°E |
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|type = Trough system |
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|location = Equator of [[4 Vesta]] |
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|length = 549.37 km<ref name=gpn/> |
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|coordinates = {{coord|9|3|S|196|14|E|globe:vesta_type:landmark|display=inline,title}} |
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|coordinates_footnotes = <ref name=gpn>{{gpn|14911|Divalia Fossae}} (Center Latitude: -9.05°, Center Longitude: 196.23°; Planetocentric, +East)</ref> |
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|discoverer = ''[[Dawn (spacecraft)|Dawn]]'' |
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|eponym = [[Divalia]] |
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}} |
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'''Divalia Fossae''' {{IPAc-en|d|ᵻ|ˈ|v|eɪ|l|i|ə|_|ˈ|f|ɒ|s|eɪ}} is the large series of parallel equatorial [[Trough (geology)|troughs]] on the giant asteroid [[4 Vesta]]. It is one of the [[List of largest rifts and valleys in the Solar System|longest chasms in the Solar System]], stretching across roughly two-thirds of Vesta's equator. The trough system is named after the Roman festival of [[Divalia]]; the name ''Divalia Fossae'' was officially approved by the [[International Astronomical Union]] (IAU) on 27 December 2011.<ref name=gpn/> |
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== Geology == |
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Divalia Fossae is one of Vesta's two major trough systems, with the other being [[Saturnalia Fossae]]. Divalia Fossae consists of numerous—in some regions, up to seven—parallel troughs ranging from a few hundred meters to about 20.5 kilometers in diameter. The troughs run roughly parallel to Vesta's equator, encircling roughly two-thirds of the body. Divalia Fossae terminates at the cratered highlands of [[Vestalia Terra]]. Divalia Fossae in turn overlaps the troughs of Saturnalia Fossae, meaning that Divalia Fossae is the younger of the two trough systems; in 2021, a team of planetary scientists led by H. C. J. Cheng used [[crater counting]] to estimate Divalia Fossae's age as roughly 3.4–3.6 billion years old.<ref name="Schafer2014"/><ref name="Cheng2021"/> |
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The troughs of Divalia Fossae appear to run concentrically around the [[Rheasilvia]] impact basin. As such, early hypotheses of the origin of Divalia Fossae have invoked the impact event that created Rheasilvia, with energy from the impact event shattering Vesta's crust and leading to normal faulting along its equator. Estimates of Divalia Fossae's age via crater counts agree with the age of the Rheasilvia basin, supporting a relationship between the two.<ref name="Cheng2021"/> However, the troughs of Divalia Fossae are not truly concentric with respect to Rheasilvia's center. Furthermore, the northernmost of Divalia Fossae's troughs cross-cut sections of Rheasilvia's rim. As the formation of Rheasilvia spanned roughly 2–3 hours, and models of fracturing in Vesta's interior take place within only minutes, this implies that Divalia Fossae formed after the Rheasilvia impact event.<ref name="Cheng2022"/> An alternative hypothesis invokes [[true polar wander]] after the Rheasilvia impact event, with the impact event additionally decreasing Vesta's rotational period. The reorientation and "spinning up" of Vesta is capable of inducing stresses across Vesta's equator whilst still remaining consistent with the observed characteristics of Divalia Fossae.<ref name="Cheng2022"/><ref name="Schmidt2011"/> A second hypothesis instead proposes that Divalia Fossae represents a large series of crater chains (''catenae'') from the debris ejected by the formation of Rheasilvia.<ref name="Hirata2023"/> |
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{{multiple image |
{{multiple image |
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| caption1 = A section of Divalia Fossa (green horizontal band), with lesser parallel troughs to the north and south |
| caption1 = A section of Divalia Fossa (green horizontal band), with lesser parallel troughs to the north and south |
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| image2 = Divalia Fossa PIA15673.jpg |
| image2 = Divalia Fossa PIA15673.jpg |
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| width2 = 400 |
| width2 = 400 |
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| alt2 = |
| alt2 = |
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| caption2 = |
| caption2 = A computer-generated view of a portion of Divalia Fossa |
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}} |
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==See also== |
==See also== |
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*[[Saturnalia |
*[[Saturnalia Fossae]] – A similar system of troughs on Vesta |
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==References== |
==References== |
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{{reflist |
{{reflist |
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|refs= |
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<ref name="Schafer2014">{{cite journal |last1=Schäfer |first1=Michael |last2=Natheus |first2=Andreas |last3=Williams |first3=David A. |display-authors=et al. |title=Imprint of the Rheasilvia impact on Vesta – Geologic mapping of quadrangles Gegania and Lucaria |date=December 2014 |journal=Icarus |volume=244 |pages=60–73 |doi=10.1016/j.icarus.2014.06.026 |bibcode=2014Icar..244...60S |hdl=2286/R.I.28060 |hdl-access=free }}</ref> |
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<ref name="Cheng2021">{{cite journal |last1=Cheng |first1=Hui Ching Jupiter |last2=Klimczak |first2=Christian |last3=Fassett |first3=Caleb I. |title=Age relationships of large-scale troughs and impact basins on Vesta |date=September 2021 |journal=Icarus |volume=366 |id=114512 |doi=10.1016/j.icarus.2021.114512 |bibcode=2021Icar..36614512C }}</ref> |
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<ref name="Cheng2022">{{cite journal |last1=Cheng |first1=Hui Ching Jupiter |last2=Klimczak |first2=Christian |title=Structural relationships in and around the Rheasilvia basin on Vesta |date=August 2022 |journal=Journal of Structural Geology |volume=161 |id=104677 |doi=10.1016/j.jsg.2022.104677 |bibcode=2022JSG...16104677C |doi-access=free }}</ref> |
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<ref name="Schmidt2011">{{cite conference |last1=Schmidt |first1=B. E. |title=Tectonics of Vesta: Indication of Spin-up and Reorientation? |date=December 2011 |conference=American Geophysical Union, Fall Meeting 2011 |id=U21B-06 |bibcode=2011AGUFM.U21B..06S }}</ref> |
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<ref name="Hirata2023">{{cite journal |last1=Hirata |first1=Naoyuki |title=Secondary Cratering From Rheasilvia as the Possible Origin of Vesta's Equatorial Troughs |date=March 2023 |journal=Journal of Geophysical Research: Planets |volume=128 |issue=3 |id=e2022JE007473 |doi=10.1029/2022JE007473 |bibcode=2023JGRE..12807473H |arxiv=2303.14955 }}</ref> |
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}} <!--- END OF REFLIST ---> |
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{{4 Vesta}} |
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[[Category: |
[[Category:Extraterrestrial valleys]] |
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[[Category: |
[[Category:Surface features of main-belt asteroids]] |
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[[Category:Surface features of 4 Vesta]] |
![]()
A section of Divalia Fossae between 45°E and 90°E
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Feature type | Trough system |
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Location | Equator of 4 Vesta |
Coordinates | 9°3′S 196°14′E / 9.050°S 196.233°E / -9.050; 196.233[1] |
Length | 549.37 km[1] |
Discoverer | Dawn |
Eponym | Divalia |
Divalia Fossae /dɪˈveɪliə ˈfɒseɪ/ is the large series of parallel equatorial troughs on the giant asteroid 4 Vesta. It is one of the longest chasms in the Solar System, stretching across roughly two-thirds of Vesta's equator. The trough system is named after the Roman festival of Divalia; the name Divalia Fossae was officially approved by the International Astronomical Union (IAU) on 27 December 2011.[1]
Divalia Fossae is one of Vesta's two major trough systems, with the other being Saturnalia Fossae. Divalia Fossae consists of numerous—in some regions, up to seven—parallel troughs ranging from a few hundred meters to about 20.5 kilometers in diameter. The troughs run roughly parallel to Vesta's equator, encircling roughly two-thirds of the body. Divalia Fossae terminates at the cratered highlands of Vestalia Terra. Divalia Fossae in turn overlaps the troughs of Saturnalia Fossae, meaning that Divalia Fossae is the younger of the two trough systems; in 2021, a team of planetary scientists led by H. C. J. Cheng used crater counting to estimate Divalia Fossae's age as roughly 3.4–3.6 billion years old.[2][3]
The troughs of Divalia Fossae appear to run concentrically around the Rheasilvia impact basin. As such, early hypotheses of the origin of Divalia Fossae have invoked the impact event that created Rheasilvia, with energy from the impact event shattering Vesta's crust and leading to normal faulting along its equator. Estimates of Divalia Fossae's age via crater counts agree with the age of the Rheasilvia basin, supporting a relationship between the two.[3] However, the troughs of Divalia Fossae are not truly concentric with respect to Rheasilvia's center. Furthermore, the northernmost of Divalia Fossae's troughs cross-cut sections of Rheasilvia's rim. As the formation of Rheasilvia spanned roughly 2–3 hours, and models of fracturing in Vesta's interior take place within only minutes, this implies that Divalia Fossae formed after the Rheasilvia impact event.[4] An alternative hypothesis invokes true polar wander after the Rheasilvia impact event, with the impact event additionally decreasing Vesta's rotational period. The reorientation and "spinning up" of Vesta is capable of inducing stresses across Vesta's equator whilst still remaining consistent with the observed characteristics of Divalia Fossae.[4][5] A second hypothesis instead proposes that Divalia Fossae represents a large series of crater chains (catenae) from the debris ejected by the formation of Rheasilvia.[6]
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