Jump to content

(614689) 2020 XL5

From Wikipedia, the free encyclopedia
(Redirected from2020 XL5)

(614689) 2020 XL5
Discovery[1][2]
Discovered byPan-STARRS 1
Discovery siteHaleakala Obs.
Discovery date12 December 2020
Designations
(614689) 2020 XL5
2020 XL5·P11aRcq[3][4]
Earth trojan[5]·NEO
Apollo[6]
Orbital characteristics[6]
Epoch21 January 2022 (JD2459600.5)
Uncertainty parameter0
Observation arc8.88 yr (3,243 days)
Earliestprecoverydate23 December 2012
Aphelion1.388AU
Perihelion0.6133 AU
1.001 AU
Eccentricity0.38713
1.00 yr (365.7 d)
316.420°
0° 59m4.269s/ day
Inclination13.847°
153.598°
87.981°
EarthMOID0.07571 AU (11,326,000 km)
VenusMOID0.02726 AU (4,078,000 km)[2]
Physical characteristics
1.18±0.08 km[7]
0.06±0.03[7]
C[7]
20–23[2]
18.58+0.16
−0.15(r-band)[7]

(614689) 2020 XL5(provisional designation2020 XL5) is anear-Earth asteroidandEarth trojandiscovered by thePan-STARRS 1survey atHaleakala Observatory,Hawaiion 12 December 2020. Itoscillatesaround theSun–EarthL4Lagrangian point(leading 60°), one of the dynamically stable locations where the combined gravitational force acts through the Sun's and Earth'sbarycenter.Analysis of2020 XL5'strojanorbit stability suggests it will remain around Earth's L4point for at least four thousand years until gravitationalperturbationsfrom repeated close encounters withVenusdestabilize its trojan configuration. With a diameter about 1.2 km (0.75 mi),2020 XL5is the second Earth trojan discovered, after2010 TK7,[7][8]and is the largest of its kind known.

Discovery

[edit]

2020 XL5was discovered by thePan-STARRS 1survey atHaleakala Observatory,Hawaiion 12 December 2020. It was first observed in theconstellationCraterat anapparent magnitudeof 21.4.[1]The asteroid was moving at an on-sky rate of 3.02arcsecondsper minute, from a distance of 0.68 AU (102 million km; 63 million mi) from Earth.[9]

The asteroid was subsequently listed on theMinor Planet Center'sNear-Earth Object Confirmation Page(NEOCP) as P11aRcq.[4]Over two days, follow-up observations were carried out by theVišnjan Observatory(L01),ESA Optical Ground Station(J04),andCerro Tololo Observatory(807).The asteroid was identified in earlierMount Lemmon Survey(G96)observations from 26 November 2020. The listing was confirmed and publicly announced as2020 XL5on 14 December 2020.[1]

Name and numbering

[edit]

Thisminor planetwas given the permanentnumber614689 by the Minor Planet Center on 28 March 2022 and is now eligible for naming.[10]In accordance with theInternational Astronomical Union's naming conventions for near-Earth objects,2020 XL5will be given a mythological name.[11]

Orbit and classification

[edit]
Heliocentric orbit diagram of2020 XL5along with the inner planets

The orbit of2020 XL5is well known with anuncertainty parameterof 0 and a longobservation arcover 8 years. The asteroid has been identified in severalprecoveryobservations by various sky surveys, including Pan-STARRS, from dates as far back as December 2012.[6][7]

2020 XL5orbits the Sun at an average distance of 1.001AUonce every365.8days, or approximately 1Earth year.Its orbit has a higheccentricityof 0.388 and aninclinationof 13.8°with respect to theeclipticplane. Over the course of its orbit, its distance from the Sun ranges from 0.61 AU atperihelionto 1.39 AU ataphelion,crossing the orbits ofVenusandEarth.Since its orbit crosses that of Earth's while having asemi-major axisgreater than 1 AU (by a small margin),2020 XL5is classified as anApollo asteroid.[6]

Trojan orbit

[edit]
Effective potentialplot showing Earth's Lagrangian points (not to scale); contours around L4and L5representtadpole looppaths
Animation of2020 XL5's orbit from 1600 to 2500 - relative to Sun and EarthSun·Earth·2020 XL5

Trojan objectsare most easily conceived as orbiting at aLagrangian point,a dynamically stable location (where the combinedgravitationalforce acts through the Sun's and Earth'sbarycenter) 60 degrees ahead of (L4) or behind (L5) a massive orbiting body, in a type of 1:1orbital resonance.In reality, they oscillate around such a point.[5]

On 26 January 2021, amateur astronomer Tony Dunn reported that2020 XL5's nominal trajectory appears to be librating about Earth's leading L4Lagrangian point, suspecting it to be anEarth trojan.[5]Subsequent analysis confirmed modeling stability for at least several thousand years into the future based on existing orbital parameters.[12][13]This would make2020 XL5more stable than the prototype L4Earth trojan2010 TK7,which is potentially unstable on timescales of less than 2,000 years.[14]Additional follow-up observations and precoveries confirmed2020 XL5's trojan nature, and showed that it will leave trojan orbit at least 4,000 years into the future.[15][7]Numerical simulations indicate that2020 XL5was likely captured into the L4Langrangian point since the 15th century.[15]

2020 XL5's high orbital eccentricity results in wide,tadpole-shapedoscillation paths in acorotating reference framewith Earth and its Lagrangian points. Although the asteroid crosses Venus's orbit with aminimum orbit intersection distance(MOID) of 0.0273 AU (4.1 million km; 2.5 million mi),[2]perturbationsby the planet are currently negligible since its nominal orbit brings it either too high or too low from the plane of Venus's orbit.[16]Venus's influence on2020 XL5's orbit will become greater over time as theirlongitudes of the ascending nodeprecessover hundreds of years, lowering2020 XL5's Venus MOID and eventually destabilizing its trojan orbit by sending it to Earth'sL3point in several thousand years.[16]

Physical characteristics

[edit]

Photometricmeasurements of optical observations from 2020 to 2021 show that2020 XL5exhibits acolorresembling that of carbonaceousC-type asteroids.Assuming that2020 XL5'sphase curvebehaves similarly to those of C-type asteroids, theabsolute magnitude(H) of the asteroid is 18.6, which corresponds to a mean diameter about 1.18 km (0.73 mi) for a typical C-type asteroid'sgeometric albedoof 0.06.[7]This makes2020 XL5the largest Earth trojan asteroid known to date, being up to three times as large as the 0.3 km (0.19 mi)-sized2010 TK7.[7]

Because2020 XL5is only visible at lowaltitudesin the sky duringtwilight,atmospheric distortionsand scattered light from the Sun hinder accurate photometry of the asteroid'slight curve,thus information about its rotation could not be determined.[7]

Exploration

[edit]

Due to2020 XL5's high orbital inclination, arendezvousmission to the asteroid fromlow Earth orbit(LEO) would require a minimum totaldelta-vof 10.3 km/s (6.4 mi/s)—too high to be considered an ideal target for a low-energy trajectory. On the other hand, aflybytrajectory to2020 XL5from LEO could be more feasible with a minimum total delta-v of 3.3 km/s (2.1 mi/s).[7]

See also

[edit]

References

[edit]
  1. ^abc"MPEC 2020-X171: 2020 XL5".Minor Planet Electronic Circular.Minor Planet Center.14 December 2020.Retrieved5 February2021.
  2. ^abcd"(614689) = 2020 XL5".Minor Planet Center.International Astronomical Union.Retrieved5 February2021.
  3. ^"2020 XL5".NEO Exchange.Las Cumbres Observatory.14 December 2020.Retrieved6 February2021.
  4. ^abGray, Bill (14 December 2020).""Pseudo-MPEC" for P11aRcq ".Project Pluto.Retrieved6 February2021.[permanent dead link]
  5. ^abcHecht, Jeff (4 February 2021)."Second Earth Trojan Discovered".Sky & Telescope.Retrieved5 February2021.
  6. ^abcd"JPL Small-Body Database Browser: 2020 XL5"(2021-11-09 last obs.).Jet Propulsion Laboratory.Retrieved5 February2021.
  7. ^abcdefghijkSantana-Ros, T.; Micheli, M.; Faggioli, L.; Cennamo, R.; Devogèle, M.; Alvarez-Candal, A.; et al. (February 2022)."Orbital stability analysis and photometric characterization of the second Earth Trojan asteroid 2020 XL5"(PDF).Nature Communications.13(447): L25.Bibcode:2022NatCo..13..447S.doi:10.1038/s41467-022-27988-4.PMC8807697.PMID35105878.
  8. ^Chang, Kenneth (2 February 2022)."Astronomers Find a New Asteroid Sharing Earth's Orbit - The Trojan asteroid 2020 XL5, which follows the same path around the sun as our planet, was revealed only after a decade of searching".The New York Times.Retrieved2 February2022.
  9. ^"2020XL5 Ephemerides".Near Earth Objects – Dynamic Site(Ephemerides at discovery (obs. code F51)). Department of Mathematics, University of Pisa, Italy.Retrieved6 February2021.
  10. ^"M.P.C. 139917"(PDF).Minor Planet Circular.Minor Planet Center. 28 March 2022. p. 1529.Retrieved14 April2022.
  11. ^"Rules and Guidelines for Naming Non-Cometary Small Solar-System Bodies"(PDF).IAU WG Small Body Nomenclature.International Astronomical Union. 20 December 2021. p. 8.Retrieved14 April2022.
  12. ^Vitagliano, Aldo (28 January 2021)."Re: Could newly-discovered 2020 XL5 be an Earth Trojan?".groups.io.Retrieved6 February2021.
  13. ^de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (18 February 2021)."Transient Terrestrial Trojans: Comparative Short-term Dynamical Evolution of 2010 TK7and 2020 XL5".Research Notes of the American Astronomical Society.5(2): 29.Bibcode:2021RNAAS...5...29D.doi:10.3847/2515-5172/abe6ad.
  14. ^Connors, Martin; Wiegert, Paul; Veillet, Christian (July 2011). "Earth's Trojan asteroid".Nature.475(7357): 481–483.Bibcode:2011Natur.475..481C.doi:10.1038/nature10233.PMID21796207.S2CID205225571.
  15. ^abHui, Man-To; Wiegert, Paul A.; Tholen, David J.; Föhring, Dora (November 2021)."The Second Earth Trojan 2020 XL5".The Astrophysical Journal Letters.922(2): L25.arXiv:2111.05058.Bibcode:2021ApJ...922L..25H.doi:10.3847/2041-8213/ac37bf.S2CID243860678.
  16. ^abDunn, Tony (2 January 2021)."Re: Could newly-discovered 2020 XL5 be an Earth Trojan?".groups.io.Retrieved6 February2021.
[edit]
Retrieved from "https://en.wikipedia.org/w/index.php?title=(614689)_2020_XL5&oldid=1235505846"