594913 ꞌAylóꞌchaxnim

ꞌAylóꞌchaxnim was discovered by the Zwicky Transient Facility (ZTF) survey at the Palomar Observatory on 4 January 2020, by astronomers Bryce Bolin, Frank Masci, and Quanzhi Ye. The discovery formed part of a campaign for detecting interior-Earth asteroids (Atiras) using the wide-field ZTF camera on the 1.22-meter Samuel Oschin telescope at the Palomar Observatory. The detection of such objects is difficult due to their close proximity to the Sun: asteroids within the orbit of Venus never reach solar elongations greater than 47 degrees, meaning that they are only observable during twilight as the Sun is below the Earth's horizon. Because of this, inner-Venusian asteroids could only be observed within a short time frame, hence why the ZTF camera was used since it can effectively detect transient objects.

At the time of discovery, ꞌAylóꞌchaxnim was located in the constellation Aquarius,{{efn|The celestial coordinates of ꞌAylóꞌchaxnim at the time of discovery are {{RA|21|24|49.90}} and {{Dec|-06|08|41.8}}. See Aquarius for constellation coordinates.}} at an apparent magnitude around 18. The discovery of ꞌAylóꞌchaxnim was reported by astronomer Bryce Bolin, and was subsequently listed on the Minor Planet Center's Near-Earth Object Confirmation Page (NEOCP) on 4 January 2020. Follow-up observations were then conducted at various observatories in order to determine the asteroid's orbit based on its orbital motion. The discovery of the asteroid was then formally announced in a Minor Planet Electronic Circular issued by the MPC on 8 January 2020. Follow-up observations were later conducted in November 2020 by the Palomar and Xingming observatories, reducing ꞌAylóꞌchaxnim's uncertainty parameter to 5.

Upon discovery, the asteroid was given the internal designation ZTF09k5. The Minor Planet Center (MPC) gave it the provisional designation {{mp|2020 AV|2}} on 8 January 2020, after follow-up observations sufficiently determined its orbit. After its orbit had been determined to sufficient precision, the MPC assigned it the permanent number 594913 on 20 September 2021 ({{small|M.P.C. 135125}}). Its name was approved on 8 November 2021.[https://www.wgsbn-iau.org/files/Bulletins/V001/WGSBNBull_V001_011.pdf WGSBN Bulletin 1, #11] {{lang|lui|ꞌAylóꞌchaxnim}} means 'Venus girl' in the indigenous Luiseño language of southern California.{{efn|The name is derived from {{lang|lui|ꞌaylóchax}} 'morning star' (also 'food left overnight'), which in turn derives ({{lang|lui|ꞌa-ylócha-x}}) from {{lang|lui|yulóchax}} 'to stay the night, be kept overnight'.William Bright (1968) A Luiseño Dictionary. University of California Press.Eric Elliott (1999) Dictionary of Rincón Luiseño. University of California at San Diego doctoral dissertation. The glottal stop in the verb {{lang|lui|yulóchax}} occurs automatically (ch becomes ꞌch after a stressed vowel) and is not normally written (Elliot 1999: 15).}} 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.

File:2020AV2orbit.jpg pole]]

ꞌAylóꞌchaxnim is the only asteroid known to have an orbit completely within Venus's orbit. With an aphelion distance of approximately 0.654 astronomical units (AU), it has the smallest known aphelion of all asteroids. In comparison, Venus's average orbital distance from the Sun is 0.723 AU, with a perihelion distance of 0.718 AU. ꞌAylóꞌchaxnim is formally classified as an Atira asteroid by the Minor Planet Center due it having an orbit within that of Earth. However, unlike previously known Atira asteroids, ꞌAylóꞌchaxnim's orbit is contained within that of Venus, thus it falls into the proposed category of Vatira asteroids—a subclass of Atira asteroids with aphelion distances less than Venus's perihelion distance (hence the name: a portmanteau of 'Venus' and 'Atira'). ꞌAylóꞌchaxnim is technically classified as a near-Earth object under the Atira classification, though the asteroid's minimum orbit intersection distance from Earth is {{Convert|0.346|AU|e6km|abbr=unit|lk=on}}.

The orbit of ꞌAylóꞌchaxnim is well-secured with an uncertainty parameter of 2. The asteroid orbits the Sun in approximately 151 days (0.41 years), with a semi-major axis of approximately 0.5554 AU. {{mp|2020 AV|2}}'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. 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. ꞌAylóꞌchaxnim's orbit is also moderately inclined to the ecliptic by approximately 15.9 degrees. 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. The asteroid's minimum orbit intersection distance from Mercury and Venus is about {{cvt|0.066|AU|e6km}} and {{cvt|0.079|AU|e6km}}, respectively.

ꞌAylóꞌchaxnim is approximately tied with {{mpl|2019 LF|6}} (0.5553 AU) as having the second-smallest known orbital period and semi-major axis among all asteroids, though {{mp|2019 LF|6}} has a slightly smaller semi-major axis. In this case, ꞌAylóꞌchaxnim has the third-smallest known semi-major axis among all asteroids.

ꞌAylóꞌchaxnim had likely originated from the main asteroid belt, where its orbit was locked in a secular resonance that caused its orbital eccentricity to gradually increase over time, evolving onto an Earth-crossing orbit. Subsequent close encounters with Earth, Venus, and Mercury resulted in gravitational perturbations of the asteroid's orbit, reducing its momentum and causing it to orbit closer to the Sun. Such inward orbital migration is thought to be rare. Near-Earth asteroids transitioning into the Vatira region often have unstable, short-term orbits due to frequent gravitational perturbations by Venus and Mercury. ꞌAylóꞌchaxnim rarely crosses the orbits of Mercury and Venus, which reduces the number of close encounters with either planet that would otherwise perturb ꞌAylóꞌchaxnim's orbit. Nevertheless its orbit is likely to be stable for less than a million years, unless it is on (or enters soon) a nearby 3:2 mean-motion resonance with Venus, which could extend its stability to a few million years.

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. The Kozai resonance often disrupts the orbits of Vatira asteroids, albeit it can also lead to orbital stability for some unperturbed Vatira asteroids. 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.

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. After 10 million years from the present, ꞌAylóꞌchaxnim will have most likely collided with Venus.

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.{{cite journal

|title = Preliminary estimates of the Zwicky Transient Facility 'Ayló'chaxnim asteroid population completeness

|display-authors = etal

|first1 = B. T. |last1 = Bolin

|first2 = T. |last2 = Ahumada

|first3 = P. |last3 = van Dokkum

|first4 = C. |last4 = Fremling

|first5 = K. K. |last5 = Hardegree-Ullman

|first6 = J. N. |last6 = Purdum

|date = April 2023

|journal = Icarus

|volume = 394

|pages = 115442

|url = https://www.sciencedirect.com/science/article/abs/pii/S0019103523000192

|doi = 10.1016/j.icarus.2023.115442

|arxiv = 2009.04125|bibcode = 2023Icar..39415442B

|s2cid = 255999613

}}

ꞌAylóꞌchaxnim is estimated to have an absolute magnitude (H) of approximately 16.2. The medium diameter of ꞌAylóꞌchaxnim is expected to be larger than {{cvt|1|km|mi}}. Assuming that the albedo is between 0.25 and 0.05, its diameter should be around {{val|1|–|3|u=km}}, respectively. 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.

Visible and near-infrared spectroscopy by the Roque de los Muchachos Observatory in 2020 suggests that ꞌAylóꞌchaxnim has a reddish surface that is olivine-rich, based on the presence of a 1 μm absorption feature characteristic of S-type asteroids. The abundance of olivine in the surface of ꞌAylóꞌchaxnim suggests that it could be a mantle asteroid formed as a fragment from the rocky mantles of large, internally differentiated bodies. The absorption features in ꞌAylóꞌchaxnim's spectrum appear to be intermediate between the S-type and A-type spectral classes, hence it is classified as an Sa-type asteroid. Assuming an average albedo of 0.22 for S-type asteroids, ꞌAylóꞌchaxnim's diameter can be constrained to approximately {{cvt|1.5|km|mi}}.

• Vulcanoids – a hypothetical population of asteroids within Mercury's orbit
• {{mpl|2019 AQ|3}}, a dynamically-changing Atira asteroid that may have once been a Vatira asteroid
• {{mpl|524522 Zoozve}}, a temporary quasi-satellite of Venus
• {{mpl|2013 ND|15}}, the first known Venus trojan

{{notelist}}

{{reflist|refs=

{{cite web

|type = 2021-09-04 last obs.

|title = JPL Small-Body Database Browser: 2020 AV2

|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3985571

|publisher = Jet Propulsion Laboratory

|access-date = 9 January 2020

|archive-url = https://web.archive.org/web/20200111003446/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3985571

|archive-date = 11 January 2020

|url-status = live}}

{{cite web

|title = 2020 AV2

|work = Minor Planet Center

|publisher = International Astronomical Union

|url = http://www.minorplanetcenter.net/db_search/show_object?object_id=2020+AV2

|access-date= 10 January 2020}}

{{cite web

|title = MPC/MPO/MPS Archive

|work = Minor Planet Center

|url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html

|access-date= 30 September 2021}}

{{cite web

|type = Q < 0.983 (au)

|title = JPL Small-Body Database Search Engine

|url = https://ssd.jpl.nasa.gov/sbdb_query.cgi?obj_group=all;obj_kind=all;obj_numbered=all;OBJ_field=0;ORB_field=0;c1_group=ORB;c1_item=Bn;c1_op=%3C;c1_value=0.983;table_format=HTML;max_rows=100;format_option=comp;c_fields=AcBiBhBnBgBjBrCkAiAp;.cgifields=format_option;.cgifields=ast_orbit_class;.cgifields=table_format;.cgifields=obj_kind;.cgifields=obj_group;.cgifields=obj_numbered;.cgifields=com_orbit_class&query=1&c_sort=BhA

|publisher = Jet Propulsion Laboratory

|access-date= 10 January 2020}}

{{cite web

|title = 2020AV2

|work = Near Earth Objects – Dynamic Site

|publisher = Department of Mathematics, University of Pisa, Italy

|url = https://newton.spacedys.com/neodys/index.php?n=2020av2&pc=1.1.0

|access-date = 10 January 2020}}

{{cite web

|url = http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html

|title = Conversion of Absolute Magnitude to Diameter for Minor Planets

|first = D.

|last = Bruton

|work = Department of Physics, Engineering, and Astronomy

|publisher = Stephen F. Austin State University

|access-date = 11 January 2020

|archive-url = https://web.archive.org/web/20081210190134/http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html

|archive-date = 10 December 2008

|url-status = live

}}

{{cite web

|title = MPEC 2020-A99 : 2020 AV2

|url = https://www.minorplanetcenter.net/mpec/K20/K20A99.html

|display-authors = etal

|first = B.

|last = Bolin

|work = Minor Planet Electronic Circular

|publisher = Minor Planet Center

|date = 8 January 2020

|access-date = 9 January 2020

|archive-url = https://web.archive.org/web/20200111120557/https://www.minorplanetcenter.net/mpec/K20/K20A99.html

|archive-date = 11 January 2020

|url-status = live

}}

{{cite news

|title = Meet 2020 AV2, the first asteroid found that stays inside Venus's orbit!

|url = https://www.syfy.com/syfywire/meet-2020-av2-the-first-asteroid-found-that-stays-inside-venuss-orbit

|first = Phil

|last = Plait

|work = Bad Astronomy

|publisher = Syfy Wire

|date = 10 January 2020

|access-date = 10 January 2020

|archive-url = https://web.archive.org/web/20200110182240/https://www.syfy.com/syfywire/meet-2020-av2-the-first-asteroid-found-that-stays-inside-venuss-orbit

|archive-date = 10 January 2020

|url-status = live

}}

{{cite news

|title = 2020 AV2, the first intervenusian asteroid ever discovered: an image – 08 Jan. 2020

|url = https://www.virtualtelescope.eu/2020/01/09/2020-av2-the-first-intervenusian-asteroid-ever-discovered-an-mage-08-jan-2020/

|first = Gianluca

|last = Masi

|publisher = Virtual Telescope Project

|date = 9 January 2020

|access-date = 9 January 2020

|archive-url = https://web.archive.org/web/20200111001915/https://www.virtualtelescope.eu/2020/01/09/2020-av2-the-first-intervenusian-asteroid-ever-discovered-an-mage-08-jan-2020/

|archive-date = 11 January 2020

|url-status = live

}}

{{cite news

|title = First Asteroid Found Inside Orbit of Venus

|url = https://www.caltech.edu/about/news/first-asteroid-found-inside-orbit-venus

|first = Whitney

|last = Clavin

|publisher = California Institute of Technology

|date = 15 January 2020

|access-date = 17 January 2020

|archive-url = https://web.archive.org/web/20200202021641/https://www.caltech.edu/about/news/first-asteroid-found-inside-orbit-venus

|archive-date = 2 February 2020

|url-status = live

}}

{{cite journal

|title = The orbital distribution of Near-Earth Objects inside Earth's orbit

|url = https://static1.squarespace.com/static/5743c691d51cd42eed1e15ea/t/57451dc89f72665be88257b5/1464147402569/Greenstreetetal2012_NEOSSat1model.pdf

|first1 = Sarah

|last1 = Greenstreet

|first2 = Henry

|last2 = Ngo

|first3 = Brett

|last3 = Gladman

|date = January 2012

|journal = Icarus

|volume = 217

|issue = 1

|pages = 355–366

|doi = 10.1016/j.icarus.2011.11.010

|bibcode = 2012Icar..217..355G

|hdl = 2429/37251

|quote = 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.

|access-date = 11 January 2020

|archive-url = https://web.archive.org/web/20190529135450/https://static1.squarespace.com/static/5743c691d51cd42eed1e15ea/t/57451dc89f72665be88257b5/1464147402569/Greenstreetetal2012_NEOSSat1model.pdf

|archive-date = 29 May 2019

|url-status = live

|hdl-access= free

}}

{{cite journal

|title = Searching for inner-Earth objects: a possible ground-based approach

|first1 = Giancula

|last1 = Masi

|date = February 2003

|journal = Icarus

|volume = 163

|issue = 1

|pages = 389–397

|doi = 10.1016/S0019-1035(03)00082-4

|bibcode = 2003Icar..163..389M

}}

{{cite journal

|title = Hot and Eccentric: The Discovery of 2019 LF₆ as a New Step in the Quest for the Vatira Population

|first1 = Carlos

|last1 = de la Fuente Marcos

|first2 = Raúl

|last2 = de la Fuente Marcos

|date = 25 July 2019

|journal = Research Notes of the American Astronomical Society

|volume = 3

|issue = 7

|pages = 106

|doi = 10.3847/2515-5172/ab346c

|bibcode = 2019RNAAS...3..106D

|s2cid = 201405666

|doi-access = free

}}

{{cite journal

|title = Understanding the evolution of Atira-class asteroid 2019 AQ₃, a major step towards the future discovery of the Vatira population

|url = https://academic.oup.com/mnras/article-abstract/487/2/2742/549830

|first1 = Carlos |last1 = de la Fuente Marcos

|first2 = Raúl |last2 = de la Fuente Marcos

|date = 1 August 2019

|journal = Monthly Notices of the Royal Astronomical Society

|volume = 487

|issue = 2

|pages = 2742–2752

|doi = 10.1093/mnras/stz1437

|doi-access = free

|arxiv = 1905.08695

|bibcode = 2019MNRAS.487.2742D|s2cid = 160009327

}}

{{cite journal

|title = A Twilight Search for Atiras, Vatiras and Co-orbital Asteroids: Preliminary Results

|display-authors = etal

|first1 = Quanzhi |last1 = Ye

|first2 = Frank J. |last2 = Masci

|first3 = Wing-Huen |last3 = Ip |author-link3= Ip Wing-huen

|first4 = Thomas A. |last4 = Prince

|first5 = George |last5 = Helou

|first6 = Davide |last6 = Farnocchia

|date = December 2019

|journal = The Astronomical Journal

|volume = 159

|issue = 2

|pages = 70

|doi = 10.3847/1538-3881/ab629c

|arxiv = 1912.06109

|s2cid = 209324310

|doi-access = free

}}

{{cite journal

|title = Orbital Dynamics of 2020 AV2: the First Vatira Asteroid

|first = Sarah |last = Greenstreet

|date = 1 March 2020

|journal = Monthly Notices of the Royal Astronomical Society: Letters

|url = https://academic.oup.com/mnrasl/article-abstract/493/1/L129/5731877

|volume = 493

|issue = 1

|pages = L129–L131

|doi = 10.1093/mnrasl/slaa025

|doi-access = free |arxiv = 2001.09083

|bibcode = 2020MNRAS.493L.129G|s2cid = 210911743 }}

{{cite journal

|title = On the orbital evolution of 2020 AV2, the first asteroid ever observed to go around the Sun inside the orbit of Venus

|first1 = Carlos

|last1 = de la Fuente Marcos

|first2 = Raúl

|last2 = de la Fuente Marcos

|date = 1 May 2020

|journal = Monthly Notices of the Royal Astronomical Society: Letters

|url = https://academic.oup.com/mnrasl/article-abstract/494/1/L6/5740740

|volume = 494

|issue = 1

|pages = L6–L10

|doi = 10.1093/mnrasl/slaa027

|doi-access = free

|arxiv = 2002.03033

|bibcode = 2020MNRAS.494L...6D

|s2cid = 211068996

|access-date = 3 March 2020

|archive-url = https://web.archive.org/web/20200602023509/https://academic.oup.com/mnrasl/article-abstract/494/1/L6/5740740

|archive-date = 2 June 2020

|url-status = live}}

{{cite journal

|title = First asteroid found within Venus's orbit could be a clue to missing 'mantle' asteroids

|url = https://www.science.org/content/article/first-asteroid-found-within-venus-s-orbit-could-be-clue-missing-mantle-asteroids

|first = Nola |last = Redd

|journal = Science Magazine

|publisher = American Association for the Advancement of Science

|doi = 10.1126/science.abd6026

|date = 1 July 2020

|s2cid = 225557797

|access-date= 9 September 2020}}

{{cite journal

|title = Physical characterization of 2020 AV₂, the first known asteroid orbiting inside Venus orbit

|url = https://academic.oup.com/mnras/article-abstract/496/3/3572/5859506

|first1 = M. |last1 = Popescu

|first2 = J. |last2 = de León

|first3 = C. |last3 = de la Fuente Marcos

|first4 = O. |last4 = Vaduvescu

|first5 = R. |last5 = de la Fuente Marcos

|first6 = J. |last6 = Licandro

|first7 = V. |last7 = Pinter

|first8 = O. |last8 = Zamora

|first9 = C. |last9 = Fariña

|first10 = L. |last10 = Curelaru

|date = 11 August 2020

|access-date = 8 July 2020

|journal = Monthly Notices of the Royal Astronomical Society

|volume = 496

|issue = 3

|pages = 3572–3581

|doi = 10.1093/mnras/staa1728

|doi-access = free

|bibcode = 2020MNRAS.496.3572P

|arxiv = 2006.08304

|s2cid = 219687045}}

{{cite journal

|title = The discovery and characterization of a kilometre sized asteroid inside the orbit of Venus

|display-authors = etal

|first1 = B. T. |last1 = Bolin

|first2 = T. |last2 = Ahumada

|first3 = P. |last3 = van Dokkum

|first4 = C. |last4 = Fremling

|first5 = M. |last5 = Granvik

|first6 = K. K. |last6 = Hardegree-Ullman

|date = August 2022

|journal = Monthly Notices of the Royal Astronomical Society: Letters

|volume = 517

|issue = 1

|pages = L49–L54

|url = https://academic.oup.com/mnrasl/article/517/1/L49/6665933

|doi = 10.1093/mnrasl/slac089

|doi-access = free

|arxiv = 2208.07253

|bibcode = 2022MNRAS.517L..49B

|s2cid = 251564734}}

{{cite web

|title = MPEC 2020-W156 : 2020 AV2

|url = https://minorplanetcenter.net/mpec/K20/K20WF6.html

|work = Minor Planet Electronic Circular

|publisher = Minor Planet Center

|date = 25 November 2020

|access-date= 25 November 2020}}

}}

• [https://www.virtualtelescope.eu/2020/01/09/2020-av2-the-first-intervenusian-asteroid-ever-discovered-an-mage-08-jan-2020/ 2020 AV2, the first intervenusian asteroid ever discovered], Gianluca Masi, The Virtual Telescope Project 2.0, 9 Jan 2020
• [https://www.syfy.com/syfywire/meet-2020-av2-the-first-asteroid-found-that-stays-inside-venuss-orbit Meet 2020 AV2, the first asteroid found that stays inside Venus's orbit!], by Phil Plait, 10 Jan 2020
• [https://earthsky.org/space/2020-av2-1st-intervenusian-asteroid Meet 2020 AV2, the 1st asteroid entirely within the orbit of Venus], by Gianluca Masi, 10 Jan 2020
• [https://www.science.org/content/article/first-asteroid-found-within-venus-s-orbit-could-be-clue-missing-mantle-asteroids First asteroid found within Venus's orbit could be a clue to missing 'mantle' asteroids], Nola Redd, Science, 1 July 2020
• {{NeoDys|2020av2}}
• {{JPL small body}}

{{2020 in space}}

{{Minor planets navigator | |number=594913 | }}

{{Small Solar System bodies}}

{{Portal bar|Astronomy|Outer Space}}

{{Authority control}}

{{DEFAULTSORT:594913}}

Category:Atira asteroids

Category:Discoveries by the Zwicky Transient Facility

Aylochaxnim

#

20200104

20200104