2008 LC18
| Discovery[1][2] | |
|---|---|
| Discovered by | |
| Discovery site | Mauna Kea Obs. |
| Discovery date | 7 June 2008 |
| Designations | |
| 2008 LC18 | |
| Orbital characteristics[1] | |
| Epoch4 September 2017 (JD2458000.5) | |
| Uncertainty parameter5 | |
| Observation arc | 4.12 yr (1,506 days) |
| Aphelion | 32.445AU |
| Perihelion | 27.667 AU |
| 30.056 AU | |
| Eccentricity | 0.0795 |
| 164.78yr(60,186 days) | |
| 185.24° | |
| 0° 0m21.6s/ day | |
| Inclination | 27.496° |
| 88.493° | |
| 6.7420° | |
| Physical characteristics | |
| Dimensions | |
| 23.2[5][6] | |
| 8.2[1] | |
2008 LC18is aNeptune trojanfirst observed on 7 June 2008 by American astronomersScott SheppardandChad Trujillousing theSubaru TelescopeatMauna Kea Observatorieson Hawaii, United States.[6]It was the first object found in Neptune's trailingL5Lagrangian pointand measures approximately 100 kilometers in diameter.[5]
Orbit and classification
[edit]Neptune trojans areresonant trans-Neptunian objectsin a1:1mean-motionorbital resonancewith Neptune. Thesetrojanshave asemi-major axisand anorbital periodvery similar to Neptune's (30.10 AU; 164.8 years).
2008 LC18belongs to the trailingL5group, which follow 60°behind Neptune's orbit. It orbits the Sun with a semi-major axis of 30.056AUat a distance of 27.7–32.4 AU once every 164 years and 9 months (60,186 days). Its orbit has aneccentricityof 0.08 and aninclinationof 27.4°with respect to theecliptic.[1]This object has the second highest inclination of any known Neptune trojan after2011 HM102,which has 29.3°.[3]
Search for Neptune trojans
[edit]The search for L5trojans of Neptune has been impeded by the fact that this region of space is currently along the line of sight to the center of the Milky Way, an area of the sky crowded with stars.2008 LC18was found in a location where background stars are obscured by adust cloud.[6][5]The discovery of one Neptune L5trojan in a searched area of 19 square degrees suggests that there may be 150 Neptune L5trojans with a diameter greater than ~80 km (24th magnitude), similar to the estimate of such objects in Neptune'sL4swarm.[6]
New Horizons probe
[edit]2008 LC18was not close enough for investigation by theNew Horizonsspacecraft when it crossed Neptune'sL5region en route toPlutoin 2013–2014, but its discovery showed that other, more accessible Neptune trojans could potentially have been found before that time.[7]2008 LC18was 2 AU from Pluto in 1997.[8]2008 LC18crossed theecliptic planein 2011. As of 2016[update],it is 33 AU from Neptune.
Physical characteristics
[edit]The discoverers estimate that the body has a mean-diameter of 100 kilometers based on amagnitudeof 23.2.[5][6]Based on a generic magnitude-to-diameter conversion, it measures approximately 98 kilometers in diameter using anabsolute magnitudeof 8.2 with an assumedalbedoof 0.10.[4]
Numbering and naming
[edit]Due to itsorbital uncertainty,thisminor planethas not been numbered and its officialdiscoverershave not been determined.[1][2]If named, it will follow the naming scheme already established with385571 Otrera,which is to name these objects after figures related to theAmazons,an all-female warrior tribe that fought in theTrojan Waron the side of the Trojans against the Greek.[9]
References
[edit]- ^abcdef"JPL Small-Body Database Browser: (2008 LC18)"(2012-07-22 last obs.).Jet Propulsion Laboratory.Retrieved4 August2017.
- ^abc"2008 LC18".Minor Planet Center.Retrieved4 August2017.
- ^ab"List of Neptune Trojans".Minor Planet Center.10 July 2017.Retrieved4 August2017.
- ^ab"Asteroid Size Estimator".CNEOS/JPL.Retrieved4 August2017.
- ^abcdeLakdawalla, Emily (13 August 2010)."2008 LC15, the first Trojan asteroid discovered in Neptune's L5 point".The Planetary Society.Retrieved4 August2017.
- ^abcdefSheppard, Scott S.; Trujillo, Chadwick A. (September 2010)."Detection of a Trailing (L5) Neptune Trojan".Science.329(5997): 1304.Bibcode:2010Sci...329.1304S.doi:10.1126/science.1189666.PMID20705814.S2CID7657932.
- ^"Reaching the Mid-Mission Milestone on the Way to Pluto!".New Horizons: The PI's Perspective. 18 October 2010.Retrieved9 April2019.[permanent dead link]
- ^2008 LC18 at JPL HorizonsChange "Observer Location" to @Pluto
- ^Ticha, J.; et al. (10 April 2018)."DIVISION F / Working Group for Small Body Nomenclature Working Group for Small Body Nomenclature. THE TRIENNIAL REPORT (2015 Sept 1 – 2018 Feb 15)"(PDF).IAU.Retrieved25 August2018.
External links
[edit]- AstDys-2about2008 LC18
- Scott Sheppard and the hunt for Neptune TrojansonYouTube(time 1:40 min.)
- 2008 LC18atAstDyS-2, Asteroids—Dynamic Site
- 2008 LC18at theJPL Small-Body Database
