| 词条 | Pandora (moon) | |||
| 释义 |
| name = Pandora | image = PIA21055 - Pandora Up Close.jpg | caption = View of Pandora's western hemisphere.{{efn|This view was taken by Cassini, during the spacecraft's close flyby on December 18, 2016. The image was taken from a distance of {{convert|abbr=off|40,500|km|mi}}; the closest approach by the spacecraft during its 14-year tenure in the Saturn system.}} | discoverer = Collins, Voyager 1 | discovered = October, 1980 | orbit_ref = {{sfn|Spitale Jacobson et al.|2006}} | epoch = December 31, 2003 (JD {{val|2453005.5}}) | semimajor = {{val|141720|10|u=km}} | eccentricity = {{val|0.0042}} | period = {{val|0.628504213|u=d}} | inclination = {{val|0.050|0.004|u=°}} to Saturn's equator | satellite_of = Saturn | dimensions = 104 × 81 × 64 km {{sfn|Thomas|2010}} | mean_radius = {{val|40.7|1.5|u=km|s= }}{{sfn|Thomas|2010}} | volume = {{val|p=≈ |280000|u=km3}} | mass = {{val|1.371|0.019|e=17|u=kg}}{{sfn|Thomas|2010}} | density = {{val|0.49|0.06|u=g/cm3}}{{sfn|Thomas|2010}} | surface_grav = 0.0026–0.0060 m/s2 {{sfn|Thomas|2010}} | escape_velocity = {{val|p=≈ |0.019|u=km/s}} | rotation = synchronous | axial_tilt = zero | albedo = 0.6 | single_temperature = ≈ 78 K }} Pandora ({{IPAc-en|p|æ|n|ˈ|d|ɔər|ə}} {{respell|pan|DOR|ə}}; {{lang-el|Πανδώρα}}) is an inner satellite of Saturn. It was discovered in 1980 from photos taken by the Voyager 1 probe, and was provisionally designated {{nowrap|S/1980 S 26}}.{{sfn|IAUC 3532}} In late 1985 it was officially named after Pandora from Greek mythology.{{sfn|IAUC 4157}} It is also designated as {{nowrap|Saturn XVII}}.{{sfn|USGS: Planet and Satellite Names and Discoverers}} Pandora was thought to be an outer shepherd satellite of the F Ring. However, recent studies indicate that it does not play such a role, and that only Prometheus, the inner shepherd, contributes to the confinement of the narrow ring.[1][2] It is more heavily cratered than nearby Prometheus, and has at least two large craters {{convert|30|km}} in diameter. The majority of craters on Pandora are shallow as a result of being filled with debris. Ridges and grooves are also present on moon's surface.{{sfn|Solar System, NASA: Pandora}} The orbit of Pandora appears to be chaotic, as a consequence of a series of four 118:121 mean-motion resonances with Prometheus.{{sfn|Renner et al. 2005}} The most appreciable changes in their orbits occur approximately every 6.2 years,{{sfn|Spitale Jacobson et al.|2006}} when the periapsis of Pandora lines up with the apoapsis of Prometheus and the moons approach to within about {{convert|1400|km}}. Pandora also has a 3:2 mean-motion resonance with Mimas.{{sfn|Spitale Jacobson et al.|2006}} From its very low density and relatively high albedo, it seems likely that Pandora is a very porous icy body. There is a lot of uncertainty in these values, however, so this remains to be confirmed. GalleryReferences{{Spoken Wikipedia|Pandora (moon).ogg|2010-01-10}}
1. ^{{cite web | last = Lakdawalla | first = E. | authorlink = Emily Lakdawalla | title = On the masses and motions of mini-moons: Pandora's not a "shepherd," but Prometheus still is | website = | publisher = Planetary Society | date = 2014-07-05 | url = http://www.planetary.org/blogs/emily-lakdawalla/2014/07010001-ringmoons-shepherds.html | accessdate = 2015-04-17 }} 2. ^{{cite journal|last1=Cuzzi|first1=J. N.|last2=Whizin|first2=A. D.|last3=Hogan|first3=R. C.|last4=Dobrovolskis|first4=A. R.|last5=Dones|first5=L. |last6=Showalter|first6=M. R.|last7=Colwell|first7=J. E.|last8=Scargle|first8=J. D.|title=Saturn's F Ring core: Calm in the midst of chaos|journal=Icarus|volume=232|date=April 2014|pages=157–175|issn=0019-1035|doi=10.1016/j.icarus.2013.12.027|bibcode = 2014Icar..232..157C }}
| last = Marsden | first = Brian G. | title = Satellites of Saturn | date = October 31, 1980 | format = discovery | journal = IAU Circular | volume = 3532 | url = http://www.cbat.eps.harvard.edu/iauc/03500/03532.html | accessdate = 2011-12-29 | ref = {{sfnRef|IAUC 3532}}
| last = Marsden | first = Brian G. | title = Satellites of Saturn and Pluto | date = January 3, 1986 | format = naming the moon | journal = IAU Circular | volume = 4157 | url = http://www.cbat.eps.harvard.edu/iauc/04100/04157.html | accessdate = 2011-12-29 | ref = {{sfnRef|IAUC 4157}}
| title = Saturn: Moons: Pandora | date = 4 Apr 2011 | work = Solar System Exploration: Planets | publisher = NASA | url = http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sat_Pandora | accessdate = 2011-12-29 | ref = {{sfnRef|Solar System, NASA: Pandora}}
| author = USGS/IAU | title = Planet and Satellite Names and Discoverers | date = July 21, 2006 | publisher = USGS Astrogeology | work = Gazetteer of Planetary Nomenclature | url = http://planetarynames.wr.usgs.gov/Page/Planets#SaturnianSystem | accessdate = 2011-12-29 | ref = {{sfnRef|USGS: Planet and Satellite Names and Discoverers}} External links{{Commons category|Pandora (moon)}}
2 : Moons of Saturn|Astronomical objects discovered in 1980 |
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