Editing Telesto (moon)

{{short description|Trojan moon of Saturn}}
{{Infobox planet
| name = Telesto
| image = Telesto N1507754980 2 crop.png
| image_scale = 
| caption = Telesto as seen by the ''[[Cassini–Huygens|Cassini]]'' probe on 11 October 2005
| discoverer = {{plainlist |
* [[Bradford A. Smith]]
* [[Harold Reitsema]]
* Stephen M. Larson
* John W. Fountain
  }}
| discovered = April 8, 1980
| pronounced = {{IPAc-en|t|ə|ˈ|l|ɛ|s|t|oʊ}}
| adjectives = Telestoan {{IPAc-en|t|ɛ|l|ə|ˈ|s|t|oʊ|.|ə|n}} or {{nowrap|Telestoian {{IPAc-en|t|ɛ|l|ə|ˈ|s|t|oʊ|.|i|ə|n}}}}
| named_after = [[Telesto (mythology)|Τελεστώ]] ''Telestō''
| mpc_name = Saturn XIII
| alt_names = Tethys B<br>S/1980 S 13
| semimajor = {{val|295000|u=km}}<ref name="jpl-satelem"/>
| eccentricity = {{val|0.001}}<ref name="jpl-satelem"/>
| period = {{val|1.887802|ul=d}}<ref name="jpl-satelem"/>
| inclination = 1.19° (to Saturn's equator)
| satellite_of = [[Saturn]]
| group = [[Trojan moon|L<sub>4</sub> Tethys trojan]]
| dimensions = {{val|33.2|x|23.4|x|19.2}}&nbsp;km<br/>(±&nbsp;{{val|0.6|x|0.6|x|0.4}}&nbsp;km){{sfn|Thomas & Helfenstein|2020}}{{rp|page=2}}
| mean_diameter = {{val|24.6|0.6|u=km}}{{sfn|Thomas & Helfenstein|2020}}{{rp|page=2}}
| volume = {{val|7795|u=km3}}{{efn|Calculated from Telesto's volume-equivalent sphere radius of {{val|12.3|0.3|u=km}} given by Thomas et al. (2020){{sfn|Thomas & Helfenstein|2020}}{{rp|page=2}}}}
| mass = {{val|4|e=15|u=kg|p=≈&thinsp;}} (assumed; unmeasured){{efn|Calculated by multiplying Telesto's volume with its assumed density of {{val|500|u=kg/m3}}.}}
| density = {{val|0.5|u=g/cm3|p=≈&thinsp;}} (assumed; unmeasured){{sfn|Thomas & Helfenstein|2020}}{{rp|page=3}}
| surface_grav = ≈&thinsp;{{val|0.0011|-|0.0014|u=m/s2}}{{sfn|Thomas & Helfenstein|2020}}{{rp|page=3}}
| escape_velocity = ≈&thinsp;{{V2|4e-6|16.6|3}}&nbsp;km/s at longest axis<br/>to ≈&thinsp;{{V2|4e-6|9.6|3}}&nbsp;km/s at poles<!-- V2 template uses mass in terms of e+21 kg, radius in terms of km, and number of decimal places -->
| axial_tilt = zero
| magnitude = 18.7{{sfn|Hamilton}}
}}

'''Telesto''' {{IPAc-en|t|ə|ˈ|l|ɛ|s|t|oʊ}} is a [[natural satellite|moon]] of [[Saturn]]. It was discovered by [[Bradford A. Smith|Smith]], [[Harold Reitsema|Reitsema]], [[Stephen M. Larson|Larson]] and [[John W. Fountain|Fountain]] in 1980 from ground-based observations, and was provisionally designated '''{{nowrap|S/1980 S 13}}'''.{{sfn|IAUC 3466}} In the following months, several other apparitions were observed: {{nowrap|S/1980 S 24}},{{sfn|IAUC 3484}} {{nowrap|S/1980 S 33}},{{sfn|IAUC 3605}} and {{nowrap|S/1981 S 1}}.{{sfn|IAUC 3593}}

In 1983 it was officially named after [[Telesto (mythology)|Telesto]] of [[Greek mythology]].{{efn|name=mythology}} It is also designated as '''{{nowrap|Saturn XIII}}''' or '''Tethys B'''.

Telesto is co-orbital with [[Tethys (moon)|Tethys]], residing in Tethys's leading [[Lagrangian point]] ({{L4}}). This relationship was first identified by [[#{{sfnRef|Seidelmann Harrington et al. 1981}}|Seidelmann ''et al.'']] in 1981.{{sfn|Seidelmann Harrington et al. 1981}} Another moon, [[Calypso (moon)|Calypso]], resides in the other (trailing) Lagrangian point of Tethys, 60 degrees in the other direction from Tethys. The Saturnian system has two additional [[trojan moon]]s. It eclipsed [[Tethys (moon)|Tethys]] in 2024.{{cn|date=May 2025}}

== Exploration ==

The ''[[Cassini-Huygens|Cassini]]'' probe performed a distant flyby of Telesto on October 11, 2005. The resulting images show that its surface is surprisingly smooth, devoid of small [[impact crater]]s. __NOTOC__

== Notes ==
{{notelist|notes=

{{efn
| name = mythology
| Transactions of the International Astronomical Union, Vol. XVIIIA, 1982 (confirms Janus, names Epimetheus, Telesto, Calypso) (mentioned in {{harvnb|IAUC 3872}})
}}

}}

== References ==
=== Citations ===
{{reflist|20em|refs=

<ref name="jpl-satelem">{{cite web
  |title      = Planetary Satellite Mean Orbital Parameters
  |url        = https://ssd.jpl.nasa.gov/sats/elem/sep.html
  |publisher  = [[Jet Propulsion Laboratory]]
  |access-date = 5 June 2023}}</ref>

}}

=== Sources ===

* {{cite web
  | last = Hamilton
  | first = Calvin J.
  | title = Saturn's Trojan Moon Telesto
  | work = SolarViews.com
  | publisher = SolarViews
  | url = http://www.solarviews.com/eng/telesto.htm
  | access-date = 2011-12-23
  }}
* {{cite journal
  | last = Marsden
  | first = Brian G.
  | title = Satellites of Saturn
  | date = April 10, 1980
  | format = discovery
  | journal = IAU Circular
  | issue = 3466
  | url = http://www.cbat.eps.harvard.edu/iauc/03400/03466.html
  | access-date = 2011-12-23
  | ref = {{sfnRef|IAUC 3466}}
  }}
* {{cite journal
  | last = Marsden
  | first = Brian G.
  | title = Satellites of Saturn
  | date = June 6, 1980
  | journal = IAU Circular
  | issue = 3484
  | url = http://www.cbat.eps.harvard.edu/iauc/03400/03484.html
  | access-date = 2011-12-23
  | ref = {{sfnRef|IAUC 3484}}
  }}
* {{cite journal
  | last = Marsden
  | first = Brian G.
  | title = Satellites of Saturn
  | date = April 16, 1981
  | journal = IAU Circular
  | issue = 3593
  | url = http://www.cbat.eps.harvard.edu/iauc/03500/03593.html
  | access-date = 2011-12-23
  | ref = {{sfnRef|IAUC 3593}}
  }}
* {{cite journal
  | last = Marsden
  | first = Brian G.
  | title = Satellites of Saturn
  | date = May 18, 1981
  | journal = IAU Circular
  | issue = 3605
  | url = http://www.cbat.eps.harvard.edu/iauc/03600/03605.html
  | access-date = 2011-12-23
  | ref = {{sfnRef|IAUC 3605}}
  }}
* {{cite journal
  | last = Marsden
  | first = Brian G.
  | title = Satellites of Jupiter and Saturn
  | date = September 30, 1983
  | journal = IAU Circular
  | issue = 3872
  | url = http://www.cbat.eps.harvard.edu/iauc/03800/03872.html
  | access-date = 2011-12-23
  | ref = {{sfnRef|IAUC 3872}}
  }}
* {{cite journal| doi = 10.1016/0019-1035(81)90172-X| last1 = Seidelmann | first1 = P. K.| last2 = Harrington | first2 = R. S.| last3 = Pascu | first3 = D.| last4 = Baum | first4 = W. A.| last5 = Currie | first5 = D. G.| last6 = Westphal | first6 = J. A.| last7 = Danielson | first7 = G. E.| year = 1981| title = Saturn satellite observations and orbits from the 1980 ring plane crossing| journal = Icarus| volume = 47| issue = 2| pages = 282| bibcode = 1981Icar...47..282S| ref = {{sfnRef|Seidelmann Harrington et al. 1981}}}}
* {{cite journal| doi = 10.1016/j.icarus.2010.01.025| last1 = Thomas| first1 = P. C.| date = July 2010| title = Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission| journal = Icarus| volume = 208| issue = 1| pages = 395–401| url = http://www.ciclops.org/media/sp/2011/6794_16344_0.pdf| bibcode = 2010Icar..208..395T| access-date = 2015-09-04| archive-date = 2011-09-27| archive-url = https://web.archive.org/web/20110927185355/http://www.ciclops.org/media/sp/2011/6794_16344_0.pdf| url-status = dead}}
* {{cite journal
  |ref = {{sfnRef|Thomas & Helfenstein|2020}}
  |first1 = P. C. |last1 = Thomas
  |first2 = P. |last2 = Helfenstein
  |title      = The small inner satellites of Saturn: Shapes, structures and some implications
  |journal    = Icarus
  |date       = July 2020
  |volume     = 344
  |id         = 113355
  |pages      = 20
  |doi        = 10.1016/j.icarus.2019.06.016
  |bibcode    = 2020Icar..34413355T|s2cid = 197474587 }}

== External links ==

{{Commons category|Telesto}}
{{Spoken Wikipedia|Telesto (moon).ogg|date=2010-01-15}}
* [https://web.archive.org/web/20190423151718/https://solarsystem.nasa.gov/moons/saturn-moons/telesto/in-depth/  NASA - Telesto Profile]
**[http://solarsystem.nasa.gov NASA's Solar System Exploration]
* [https://web.archive.org/web/20060903193132/http://www.planetary.org/explore/topics/saturn/telesto.html The Planetary Society: Telesto]

{{Moons of Saturn|state=uncollapsed}}
{{Tethys (moon)}}
{{Saturn}}

{{DEFAULTSORT:Telesto (Moon)}}
[[Category:Moons of Saturn]]
[[Category:Trojan moons]]
[[Category:Astronomical objects discovered in 1980|19800408]]
[[Category:Moons with a prograde orbit]]