594913 ꞌAylóꞌchaxnim

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594913 ꞌAylóꞌchaxnim
Perihelion
0.4571 AU
0.5554 AU
Eccentricity0.17701
0.41 yr (151.2 d)
85.295°
2° 22m 51.424s / day
Inclination15.868°
6.706°
187.330°
Earth MOID0.34694 AU (51.9 million km)
Mercury MOID0.06561 AU
Venus MOID0.07896 AU
Physical characteristics
Mean diameter
1.7+0.6
−0.6 km[5]
0.22 (assumed for S-type asteroids)[5]
Surface temp. min mean max
(approx)[6] 330 K 350 K[6] 395 K
Sa[5]
18.0[7]
16.17±0.78[3]

594913 ꞌAylóꞌchaxnim (

semi-major axis among all asteroids.[11] With an absolute magnitude approximately 16.2, the asteroid is expected to be larger than 1 km in diameter.[4]

Discovery

ꞌAylóꞌchaxnim was discovered by the

transient objects.[13]

At the time of discovery, ꞌAylóꞌchaxnim was located in the

Minor Planet Electronic Circular issued by the MPC on 8 January 2020.[1] Follow-up observations were later conducted in November 2020 by the Palomar and Xingming observatories, reducing ꞌAylóꞌchaxnim's uncertainty parameter to 5.[14]

Nomenclature

Upon discovery, the asteroid was given the internal designation ZTF09k5.

M.P.C. 135125).[4][15] Its name was approved on 8 November 2021.[16] ꞌAylóꞌchaxnim means 'Venus girl' in the indigenous Luiseño language of southern California.[b] The name celebrates the location of the discovery (Palomar Mountain, which is on ancestral Luiseño land) and the fact that ꞌAylóꞌchaxnim is the first discovered asteroid to orbit entirely within the orbit of Venus. Being the prototype of the informally named Vatira class, its name is expected to be used to refer to this newly confirmed population.[2]

Orbit and classification

Orbit diagram of ꞌAylóꞌchaxnim, as viewed from the ecliptic pole

ꞌAylóꞌchaxnim is the only asteroid known to have an orbit completely within Venus's orbit. With an

portmanteau of 'Venus' and 'Atira').[2] ꞌAylóꞌchaxnim is technically classified as a near-Earth object under the Atira classification, though the asteroid's minimum orbit intersection distance from Earth is 0.346 AU (51.8 million km).[3]

The orbit of ꞌAylóꞌchaxnim is well-secured with an

semi-major axis of approximately 0.5554 AU.[4] 2020 AV2's orbit is close to a 3:2 mean-motion orbital resonance with Venus, meaning that ꞌAylóꞌchaxnim completes approximately three orbits for every two orbits completed by Venus.[19] The orbit of ꞌAylóꞌchaxnim is moderately eccentric, as it approaches only 0.457 AU from the Sun at perihelion, just within Mercury's aphelion distance of 0.467 AU.[3] ꞌAylóꞌchaxnim's orbit is also moderately inclined to the ecliptic by approximately 15.9 degrees.[3][10] ꞌAylóꞌchaxnim has a smaller orbital eccentricity and inclination compared to the generally expected values for typical Vatira asteroids, which were predicted to have an eccentricity around 0.4 and an inclination around 25 degrees.[19] The asteroid's minimum orbit intersection distance from Mercury and Venus is about 0.066 AU (9.9×10^6 km) and 0.079 AU (11.8×10^6 km), respectively.[4]

ꞌAylóꞌchaxnim is approximately tied with 2019 LF6 (0.5553 AU) as having the second-smallest known orbital period and semi-major axis among all asteroids,[9] though 2019 LF6 has a slightly smaller semi-major axis.[11][20] In this case, ꞌAylóꞌchaxnim has the third-smallest known semi-major axis among all asteroids.

Orbital dynamics

ꞌAylóꞌchaxnim had likely originated from the main

mean-motion resonance with Venus, which could extend its stability to a few million years.[19][21]

Dynamical modeling of ꞌAylóꞌchaxnim's orbit show that the most likely scenario for its orbital evolution is that ꞌAylóꞌchaxnim's orbit will oscillate for several millions of years before gravitational perturbations lead to the asteroid's eventual collision with a planet, most likely Venus. At 140 thousand years from the present, ꞌAylóꞌchaxnim's aphelion distance will exceed Venus's perihelion distance, as a result of the combined effects of the

Kozai resonance and gravitational perturbations. Within the Vatira region, the Kozai resonance causes the orbital inclinations and eccentricities of asteroids to oscillate over several millions of years. As a result, Vatira asteroids can become Atira-class asteroids and vice versa over time, and can cross the orbits of Mercury and Venus during these orbital oscillations.[22][19] The Kozai resonance often disrupts the orbits of Vatira asteroids, albeit it can also lead to orbital stability for some unperturbed Vatira asteroids.[23] At about 1.2 million years from the present, ꞌAylóꞌchaxnim will leave the Vatira region and will transition onto a Mercury-crossing orbit, with its perihelion oscillating around Mercury's aphelion distance before decoupling from the planet's orbit at about 2.1 million years.[19]

After decoupling from Mercury's orbit, ꞌAylóꞌchaxnim was shown to oscillate between an Atira-type orbit (

Q < 0.983 AU) and an Earth-crossing Aten-type orbit (Q > 0.983 AU), in which the asteroid's aphelion oscillates around Earth's perihelion distance of 0.983 AU. About 740 thousand years afterward, ꞌAylóꞌchaxnim will likely return to its Mercury-crossing orbit, though gravitational perturbations by Mercury and Venus will scatter it onto an Earth-crossing orbit once more before colliding with either planet. At about 4.1 million years from the present, ꞌAylóꞌchaxnim will most likely collide with Venus.[19]

Modeling of the observational selection effects of the Zwicky Transient Facility survey shows a small probability of it detecting ꞌAylóꞌchaxnim based on the current NEO model. The low probability of detection may imply an additional source of ꞌAylóꞌchaxnim asteroids in the inner Solar System such as within the orbit of Mercury.[24]

Physical characteristics

ꞌAylóꞌchaxnim is estimated to have an absolute magnitude (H) of approximately 16.2.[3] The medium diameter of ꞌAylóꞌchaxnim is expected to be larger than 1 km (0.62 mi).[4] Assuming that the albedo is between 0.25 and 0.05, its diameter should be around 1–3 km, respectively.[25] Near-Earth asteroid population models predict that at least one asteroid of this size has an orbit within that of Venus, implying that ꞌAylóꞌchaxnim could be one of the largest members of the Vatira population.[19][5]

spectral classes, hence it is classified as an Sa-type asteroid.[6] Assuming an average albedo of 0.22 for S-type asteroids, ꞌAylóꞌchaxnim's diameter can be constrained to approximately 1.5 km (0.93 mi).[6]

See also

Notes

  1. celestial coordinates of ꞌAylóꞌchaxnim at the time of discovery are 21h 24m 49.90s and −06° 08′ 41.8″.[1] See Aquarius
    for constellation coordinates.
  2. ^ The name is derived from ꞌaylóchax 'morning star' (also 'food left overnight'), which in turn derives (ꞌa-ylócha-x) from yulóchax 'to stay the night, be kept overnight'.[17][18] The glottal stop in the verb yulóchax occurs automatically (ch becomes ꞌch after a stressed vowel) and is not normally written (Elliot 1999: 15).

References

  1. ^ a b c d e f g Bolin, B.; et al. (8 January 2020). "MPEC 2020-A99 : 2020 AV2". Minor Planet Electronic Circular. Minor Planet Center. Archived from the original on 11 January 2020. Retrieved 9 January 2020.
  2. ^
    hdl:2429/37251. Archived
    (PDF) from the original on 29 May 2019. Retrieved 11 January 2020. We have provisionally named objects with 0.307 < Q < 0.718 AU Vatiras, because they are Atiras which are decoupled from Venus. Provisional because it will be abandoned once the first discovered member of this class will be named.
  3. ^ a b c d e f g h i j k "JPL Small-Body Database Browser: 2020 AV2" (2021-09-04 last obs.). Jet Propulsion Laboratory. Archived from the original on 11 January 2020. Retrieved 9 January 2020.
  4. ^ a b c d e f g "2020 AV2". Minor Planet Center. International Astronomical Union. Retrieved 10 January 2020.
  5. ^
    S2CID 251564734
    .
  6. ^
    S2CID 219687045
    . Retrieved 8 July 2020.
  7. ^ "2020AV2". Near Earth Objects – Dynamic Site. Department of Mathematics, University of Pisa, Italy. Retrieved 10 January 2020.
  8. doi:10.1093/mnrasl/slac089
    . Retrieved 1 October 2022.
  9. ^ a b c d Masi, Gianluca (9 January 2020). "2020 AV2, the first intervenusian asteroid ever discovered: an image – 08 Jan. 2020". Virtual Telescope Project. Archived from the original on 11 January 2020. Retrieved 9 January 2020.
  10. ^ a b c d Plait, Phil (10 January 2020). "Meet 2020 AV2, the first asteroid found that stays inside Venus's orbit!". Bad Astronomy. Syfy Wire. Archived from the original on 10 January 2020. Retrieved 10 January 2020.
  11. ^ a b "JPL Small-Body Database Search Engine" (Q < 0.983 (au)). Jet Propulsion Laboratory. Retrieved 10 January 2020.
  12. doi:10.1016/S0019-1035(03)00082-4
    .
  13. ^ a b c Clavin, Whitney (15 January 2020). "First Asteroid Found Inside Orbit of Venus". California Institute of Technology. Archived from the original on 2 February 2020. Retrieved 17 January 2020.
  14. ^ "MPEC 2020-W156 : 2020 AV2". Minor Planet Electronic Circular. Minor Planet Center. 25 November 2020. Retrieved 25 November 2020.
  15. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 30 September 2021.
  16. ^ WGSBN Bulletin 1, #11
  17. ^ William Bright (1968) A Luiseño Dictionary. University of California Press.
  18. ^ Eric Elliott (1999) Dictionary of Rincón Luiseño. University of California at San Diego doctoral dissertation.
  19. ^
    S2CID 210911743
    .
  20. S2CID 209324310
    .
  21. S2CID 211068996. Archived
    from the original on 2 June 2020. Retrieved 3 March 2020.
  22. S2CID 201405666
    .
  23. ^
    S2CID 160009327
    .
  24. S2CID 255999613
    .
  25. ^ Bruton, D. "Conversion of Absolute Magnitude to Diameter for Minor Planets". Department of Physics, Engineering, and Astronomy. Stephen F. Austin State University. Archived from the original on 10 December 2008. Retrieved 11 January 2020.
  26. S2CID 225557797
    . Retrieved 9 September 2020.

External links
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