| Discovery[1][2] | |
|---|---|
| Discovered by | K. Černis R. P. Boyle |
| Discovery site | VATT(Mount Graham Obs.) |
| Discovery date | 23 January 2012 |
| Designations | |
| (420356) Praamzius | |
| Pronunciation | /preɪˈæmziəs/ (Lithuanian:[prɐˈâmʑʊs]) |
Named after | Praámžius[1] (Lithuanian mythology) |
| 2012 BX85 | |
| TNO[3] · cubewano[4][5] cold[6] · distant[1] | |
| Adjectives | Praamzinian |
| Orbital characteristics[3] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 3 | |
| Observation arc | 13.08yr (4,778 d) |
| Aphelion | 43.027AU |
| Perihelion | 42.147 AU |
| 42.587 AU | |
| Eccentricity | 0.0103 |
| 277.93 yr (101,512 d) | |
| 185.10° | |
| 0° 0m 12.6s / day | |
| Inclination | 1.1001° |
| 314.26° | |
| ≈ 12 June 2158[7] ±3 months | |
| 358.38° | |
| Knownsatellites | 0 |
| Physical characteristics | |
| 191 km(est.)[6] 321 km(est.)[4] | |
| 0.09(assumed)[4] 0.20(assumed)[6] | |
| 22.09(visible)[8] | |
| 5.7[1][3] | |
420356 Praamzius (provisional designation2012 BX85) is atrans-Neptunian object from the classicalKuiper belt, located in the outermost region of theSolar System, approximately 190–320 kilometers (120–200 miles) in diameter.[4][6] It was discovered on 23 January 2012, by astronomersKazimieras Černis andRichard Boyle with the Vatican'sVATT atMount Graham Observatory in Arizona, United States. Thecold classical Kuiper belt object is possiblyvery red in color. It was named after the chief godPraamžius from Lithuanian mythology.[1]
| Epoch | Eccentricity | Refs |
|---|---|---|
| 09 Dec 2014 | 0.0018 | [a] |
| 31 Jul 2016 | 0.0032 | [b] |
| 04 Apr 2019 | 0.0103 | [3] |
| 01 Sep 2021 | 0.013 | — |
| Barycentric | 0.0078 | — |
Praamzius orbits the Sun at a distance of 42.1–43.0 AU once every 277 years and 11 months (101,512 days;semi-major axis of 42.59 AU). Its orbit has aneccentricity of 0.01 and aninclination of 1° with respect to theecliptic.[3] It is aclassical Kuiper belt object located in between the resonantplutino (39.4 AU) andtwotino (47.8 AU) populations and has a low-eccentricity orbit. With an inclination significantly less than 4–7°, it belongs to thecold rather than to the "stirred"hot population.
With an eccentricity of 0.003 in 2016,[b] Praamzius had one of the lowest eccentricities of any trans-Neptunian object, and a more circular orbit than any major planet (includingVenus, the least eccentric planet at 0.007). But the object's eccentricity varies over time due to the position of the planets(also see table). A 10 million year simulation of the orbit shows the eccentricity (emax) does not get greater than 0.03.[5]
Initial discovery was from images acquired on 23 January 2012 atVATT, onMount Graham, Arizona using a 1.8 meterreflecting telescope;[2]precovery observations from VATT and theSloan Digital Sky Survey dating back to 31 December 2002 have been accepted by theMinor Planet Center.[1] The object has been repeatedly tracked through January 2016, mostly by VATT with some supporting observations byLas Campanas Observatory. Praamzius is one of the most recently discovered minor planets to receive a numeric designation, confirming it as a distinct body with a well determined orbit. This is due to the large number of observations since and indeed before its discovery: about one every 23 to 24 days on average from 2002 to 2016, and as many as one per 10 days in the period between discovery and assignment alone. Precovery images refined the orbit even more.
Thisminor planet was named afterPraamžius ("the Eternal One", an epithet ofDievas), the Lithuanian god of the sky, peace, and friendship.[1] The officialnaming citation was published by theMinor Planet Center on 22 February 2016 (M.P.C. 98717).[9]
According toJohnston's Archive, Praamzius measures 321 kilometers in diameter based on an assumed, genericalbedo of 0.09.[4] This would qualify the object as a weakdwarf planet candidate based on the5-class taxonomic system of American astronomerMichael Brown. However, on his website, Brown estimates only a diameter of 191 kilometers due to a much higher (assumed) albedo of 0.20. As a consequence, he no longer considers Praamzius to be apossible dwarf planet.[6]
As of 2018, neither the body'scolor indices, nor its rotationallightcurve has been obtained fromphotometric observations, and itsrotation period,pole and shape remain unknown.[3][10]
