474640 Alicanto
{{Short description|Detached extreme trans-Neptunian object}}
{{Use dmy dates|date=May 2021}}
{{Infobox planet
| minorplanet = yes
| name = 474640 Alicanto
| background = #C2E0FF
| image =
| image_size =
| caption =
| discoverer = A. C. Becker
| discovery_site = Cerro Tololo
| discovered = 6 November 2004
| mpc_name = (474640) Alicanto
| alt_names = {{mp|2004 VN|112}}
| pronounced =
| named_after = Alicanto
{{small|(Chilean mythology)}}
| mp_category = TNO {{·}}detached-ETNO
| epoch = 17 December 2020 (JD 2459200.5)
| observation_arc = 15.94 yr (5,821 d)
| aphelion = 608 AU (barycentric)
618.32 AU
| perihelion = 47.289 AU
| semimajor = 328 AU (barycentric)
332.80 AU
| eccentricity = 0.8579
| period = 5900 yr (barycentric)
6071 yr (2,217,590 d)
| mean_anomaly = 0.6822°
| mean_motion = {{Deg2DMS|0.0002|sup=ms}} / day
| inclination = 25.572°
| asc_node = 65.996°
| arg_peri = 326.72°
| mean_diameter = {{plainlist|
| rotation =
| albedo = 0.04 {{small|(est.)}}
| spectral_type = {{plainlist|
- B–V {{=}} {{val|0.900|0.085}}
- V–R {{=}} {{val|0.520|0.060}}
- V–I {{=}} {{val|0.970|0.085}}
- BR {{=}} {{val|1.42|0.06}}
- Blue}}
}}
474640 Alicanto (provisional designation {{mp|2004 VN|112}}) is a detached extreme trans-Neptunian object. It was discovered on 6 November 2004, by American astronomer Andrew C. Becker at Cerro Tololo Inter-American Observatory in Chile. It never gets closer than 47 AU from the Sun (near the outer edge of the main Kuiper belt) and averages more than 300 AU from the Sun. Its large eccentricity strongly suggests that it was gravitationally scattered onto its current orbit. Because it is, like all detached objects, outside the current gravitational influence of Neptune, how it came to have this orbit cannot yet be explained. It was named after Alicanto, a nocturnal bird in Chilean mythology.
Discovery and orbit
File:Planet_nine-etnos_now.png]]
Alicanto was discovered by American astronomer A. C. Becker with the ESSENCE supernova survey on 6 November 2004 observing with the 4-meter Blanco Telescope from Cerro Tololo Inter-American Observatory.[https://www.minorplanetcenter.net/iau/mpec/K07/K07S29.html Discovery MPEC] Precovery images have been found back to September 26, 2000. Alicanto was observed by the Hubble Space Telescope in November 2008, and found not to have any detectable companions. It reached perihelion (closest approach to the Sun) in 2009 and is currently 47.7 AU from the Sun. It will be in the constellation of Cetus until 2019. It comes to opposition at the start of November.
With a perihelion greater than 40 AU, Alicanto is an extreme trans-Neptunian object which are practically detached from Neptune's gravitational influence. Its orbit is characterized by high eccentricity (0.850), moderate inclination (25.58°) and a semi-major axis of 316 AU. Upon discovery, it was classified as a trans-Neptunian object. Its orbit is well determined; as of 11 January 2017 its orbital solution is based on 34 observations spanning a data-arc of 5821 days. Alicanto's orbit is similar to that of {{mpl|2013 RF|98}}, indicating that they may have both been thrown onto the orbit by the same body, or that they may have been the same object (single or binary) at one point.
Numerical simulations based on models of Solar System formation suggest this object, along with Sedna, may be part of the inner edge of the Oort cloud.{{Cite journal |last1=Brasser |first1=R. |last2=Schwamb |first2=M. E. |date=2015-02-01 |title=Re-assessing the formation of the inner Oort cloud in an embedded star cluster – II. Probing the inner edge |url=http://academic.oup.com/mnras/article/446/4/3788/2892865/Reassessing-the-formation-of-the-inner-Oort-cloud |journal=Monthly Notices of the Royal Astronomical Society |language=en |volume=446 |issue=4 |pages=3788–3796 |doi=10.1093/mnras/stu2374 |doi-access=free |issn=1365-2966}}{{Cite journal |last1=Dones |first1=Luke |last2=Brasser |first2=Ramon |last3=Kaib |first3=Nathan |last4=Rickman |first4=Hans |date=December 2015 |title=Origin and Evolution of the Cometary Reservoirs |url=http://link.springer.com/10.1007/s11214-015-0223-2 |journal=Space Science Reviews |language=en |volume=197 |issue=1–4 |pages=191–269 |doi=10.1007/s11214-015-0223-2 |bibcode=2015SSRv..197..191D |issn=0038-6308}}
Naming
On 14 May 2021, the object was named by the Working Group for Small Bodies Nomenclature (WGSBN) after Alicanto from Chilean mythology. The nocturnal bird of the Atacama Desert has wings that shine at night with beautiful, metallic colors.
Physical characteristics
Alicanto has an absolute magnitude of 6.5 which gives a characteristic diameter of 130 to 300 km for an assumed albedo in the range 0.25–0.05.
Michael Brown's website lists it as a possible dwarf planet with a diameter of {{convert|314|km|mi}} based on an assumed albedo of 0.04. The albedo is expected to be low because the object has a blue (neutral) color. However, if the albedo is higher, the object could easily be half that size.
Alicanto's visible spectrum is very different from that of 90377 Sedna. The value of its spectral slope suggests that the surface of this object can have pure methane ices (like in the case of Pluto) and highly processed carbons, including some amorphous silicates. Its spectral slope is similar to that of {{mp|2013 RF|98}}.
Comparison
File:Distant object orbits + Planet Nine.png, and other very distant objects along with the predicted orbit of Planet Nine. The three sednoids (pink) along with the red-colored extreme trans-Neptunian object (eTNO) orbits are suspected to be aligned with the hypothetical Planet Nine while the blue-colored eTNO orbits are anti-aligned. The highly elongated orbits colored brown include centaurs and damocloids with large aphelion distances over 200 AU.]]
{{clear|left}}
See also
References
{{reflist|refs=
|author=Marc W. Buie
|author-link=Marc W. Buie
|date=2007-11-08
|title=Orbit Fit and Astrometric record for 04VN112
|publisher=SwRI (Space Science Department)
|url=http://www.boulder.swri.edu/~buie/kbo/astrom/04VN112.html
|accessdate=2008-07-17
|url-status=dead
|archiveurl=https://web.archive.org/web/20100818145946/http://www.boulder.swri.edu/~buie/kbo/astrom/04VN112.html
|archivedate=2010-08-18
}}
|type = 2016-09-03 last obs.
|title = JPL Small-Body Database Browser: 474640 (2004 VN112)
|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2474640
|publisher = Jet Propulsion Laboratory
|accessdate = 18 May 2021}}
|title = (474640) Alicanto
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=474640
|accessdate = 18 May 2021}}
|title=How many dwarf planets are there in the outer solar system? (updates daily)
|publisher=California Institute of Technology
|author=Michael E. Brown
|author-link=Michael E. Brown
|url=http://web.gps.caltech.edu/~mbrown/dps.html
|accessdate=18 September 2016}}
|title = Asteroid Size Estimator
|publisher = CNEOS NASA/JPL
|url = https://cneos.jpl.nasa.gov/tools/ast_size_est.html
|accessdate = 12 November 2017}}
|title = LCDB Data for (474640) Alicanto
|publisher = Asteroid Lightcurve Database (LCDB)
|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=474640
|accessdate = 18 May 2021}}
|title=AstDyS 2004 VN112 Ephemerides
|publisher=Department of Mathematics, University of Pisa, Italy
|url=https://newton.spacedys.com/astdys/index.php?pc=1.1.3.0&n=2004VN112
|accessdate=2014-03-28}}
|title=JPL Small-Body Database Browser: 90377 Sedna (2003 VB12)
|url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Sedna
|accessdate=2014-03-28}}
|title = WGSBN Bulletin Archive
|work = Working Group for Small Bodies Nomenclature
|date = 14 May 2021
|url = https://www.wgsbn-iau.org/files/Bulletins/index.html
|accessdate = 16 May 2021}} ([https://www.wgsbn-iau.org/files/Bulletins/V001/WGSBNBull_V001_001.pdf Bulletin #1])
|author=Horizons output
|url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272004+VN112%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%271900-01-01%27&STOP_TIME=%272200-01-01%27&STEP_SIZE=%27100%20years%27&CENTER=%27@0%27&OUT_UNITS=%27AU-D%27
|title=Barycentric Osculating Orbital Elements for 2004 VN112
|accessdate=2021-09-20}} (Ephemeris Type:Elements and Center:@0)
{{Cite journal | title=Visible spectra of (474640) 2004 VN112-2013 RF98 with OSIRIS at the 10.4 m GTC: evidence for binary dissociation near aphelion among the extreme trans-Neptunian objects | first1=Julia | last1=de León | first2=Carlos |last2=de la Fuente Marcos |last3=de la Fuente Marcos |first3=Raúl |date=May 2017 |journal=Monthly Notices of the Royal Astronomical Society: Letters|volume=467|issue=1|pages=L66–L70|doi=10.1093/mnrasl/slx003 | doi-access=free | url=https://academic.oup.com/mnrasl/article-abstract/467/1/L66/2870017/Visible-spectra-of-474640-2004-VN112-2013-RF98|arxiv=1701.02534|bibcode=2017MNRAS.467L..66D| s2cid=119419889 }}
{{cite journal|title=Binary stripping as a plausible origin of correlated pairs of extreme trans-Neptunian objects|first1=C.|last1=de la Fuente Marcos|first2=R.|last2=de la Fuente Marcos|first3=S. J.|last3=Aarseth|date=1 November 2017|journal=Astrophysics and Space Science|volume=362|issue=11|pages=198 (18pp.)|arxiv=1709.06813|bibcode=2017Ap&SS.362..198D |doi=10.1007/s10509-017-3181-1|s2cid=118890903}}
}}
External links
- [http://www.iac.es/divulgacion.php?op1=16&id=1162&lang=en New data about two distant asteroids give a clue to the possible "Planet Nine"]
- [http://www.agenciasinc.es/Noticias/Dos-asteroides-lejanos-apoyan-la-hipotesis-del-Planeta-Nueve Dos asteroides lejanos apoyan la hipótesis del Planeta Nueve]
- {{AstDys|474640}}
- {{JPL small body|id=2474640}}
{{Minor planets navigator| |number=474640 | }}
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