(420356) Praamzius

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Asteroid
(420356) Praamzius
Properties of the orbit ( animation )
Epoch:  April 27, 2019 ( JD 2,458,600.5)
Orbit type Cubewano
Major semi-axis 42,587  AU
eccentricity 0.01
Perihelion - aphelion 42.147 AU - 43.027 AU
Inclination of the orbit plane 1.1 °
Length of the ascending node 314.3 °
Argument of the periapsis 358.4 °
Time of passage of the perihelion May 6, 2154
Sidereal period 277 a 11.2 M
Physical Properties
Medium diameter 191 km
Albedo 0.09
0.20
Absolute brightness 5.7 likes
history
Explorer Kazimieras Černis
Richard P. Boyle
Date of discovery January 23, 2012
Another name 2012 BX 85
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.

(420356) Praamzius is a trans-Neptunian object in the Kuiper belt , which is classified as Cubewano . The asteroid has one of the most circular orbits in the solar system .

discovery

Praamzius was discovered on January 23, 2012 by a team of astronomers consisting of Kazimieras Černis and Richard P. Boyle at the 1.8 m VATT telescope ( Vatican Observatory ) at the Mount Graham International Observatory near Safford , Arizona . The discovery was announced on January 30, 2012. The asteroid was initially given the designation 2012 BX 85 by the IAU and later the minor planet number 420356 .

The asteroid was named on February 22, 2016 after Praamžius (also: Pramšans , Pramžimas , Praamžimas ), the oldest and highest Lithuanian god (an epithet of Dievas ), who is associated with the creation of the earth. He is the god of heaven, peace and friendship in Lithuanian mythology .

After his discovery, Praamzius was identified on December 31, 2002 recordings made by VATT and the Sloan Digital Sky Survey and so his orbit was calculated more precisely. The asteroid was observed repeatedly in January 2016, mainly by VATT with some supportive observations from the Las Campanas Observatory . In general, Praamzius is considered a very well observed asteroid; On average, one observation took place every 23 to 24 days between 2002 and 2016, and even one in 10 days between discovery and assignment. In April 2017, a total of 205 observations were made over a period of 13 years.

properties

Orbit

Praamzius orbits the sun in 277.93 years in a circular orbit between 42.14  AU and 43.03 AU from its center. The orbit eccentricity is 0.010, the orbit is 1.1 ° inclined to the ecliptic . The next time it passes through perihelion in 2154. Praamzius is thus located in the Kuiper belt and is located between the resonant Plutino (39.4 AU) and Twotino groups (47.8 AU). With the low orbit inclination of significantly less than 4–7 °, Praamzius is one of the “cold” Cubewanos, i.e. one of the KBOs whose orbits have not been significantly changed by orbital disruptions since their formation .

In fact, Praamzius' orbit is also one of the most circular in the Trans-Neptunian realm. In 2016, the eccentricity was only 0.003, which means that the asteroid even undercut the eccentricity of Venus , which has the most circular orbit of all planets. However, the eccentricity of Praamzius varies over longer periods of time (see table); however, a 10 million year orbit simulation shows that the maximum eccentricity does not exceed 0.03. Comparable objects are around 1999 CL 119 or (471196) 2010 PK 66 , but these are considered "hot" Cubewanos with much higher inclinations. In any case, Praamzius currently has the most circular orbit of at least all numbered “cold” Cubewanos.

The circular path of Praamzius (red).
Eccentricity provisions for Praamzius
date eccentricity
12/09/2014 0.0018
07/31/2016 0.0032
04/04/2019 0.0103
09/01/2021 0.0130
Barycentric 0.0078
The current determination is marked in bold .

The semi-major axis is close, but not directly on the 3: 5 orbit resonance with Neptune ; orbit and semi-axis are slightly too high for that. There can be various reasons for this: Either the proximity is purely coincidental and Praamzius is thus a classic Cubewano, or a remnant of a libration cycle that is centered on the 3: 5 resonance and the asteroid is currently on the further orbit of its oscillation, or it could also be part of more exotic resonances such as 7:12, 10:17 or 17:28, which would better fit the observed orbit.

Although Praamzius has a comparatively dense and quite precise observation history and the uncertainty values ​​are relatively low, a reliable determination is nevertheless difficult. The uncertainty values ​​are just high enough to allow all of the scenarios mentioned, with the exception of the 7:12 response. However, this would only require a slight long-term vibration to be realistic as well.

size

A calculated diameter of 321 km is currently assumed; this value is based on an assumed reflectivity of 9%. This would make Praamzius a weak dwarf planet candidate , based on Mike Brown's taxonomic 5-class system . However, the latter itself estimates the diameter of the asteroid at 191 km due to a much higher assumed albedo of 20%. As a result, Brown no longer assesses Praamzius as a possible dwarf planet candidate and it is therefore unclear whether Praamzius could be in hydrostatic equilibrium . The apparent magnitude of Praamzius is 22.09 m .

Until 2018 nothing could be learned about color indices and rotating light curves, so that the period of rotation, the alignment of the poles and the shape of the asteroid are so far unknown. However, analyzes of pre-discovery photos between 2002 and 2007 in the visible spectrum show that Praamzius could be one of the reddest objects in the solar system, since the images in the green filter were more than 1.5 m weaker than in the red filter, which provides information on composition and origin can. In general, relatively small “cold” Cubewanos are mostly reddish. Because the orbits of this group of asteroids do not vary greatly in relation to distance from the Sun, their surfaces are older, more weathered, and covered in tholines . It is quite possible that Praamzius was formed roughly in the orbit it is in today.

Provisions of the diameter for Praamzius
year Dimensions km source
2018 321.0 Johnston
2018 191.0 Brown
The most precise determination is marked in bold .

See also

Individual evidence

  1. ↑ MPC MPEC 2012-B100: 2012 BX85
  2. ↑ MPC (420356) Praamzius = 2012 BX85
  3. ↑ M. Buie Orbit Fit and Astrometric record for 420356
  4. ↑ JPL : JPL Archive: 420356 (2012 BX85) (December 2014) ( Memento from February 13, 2018 in the Internet Archive )
  5. ↑ MPC : MPC Archive: 420356 (2012 BX85) (July 2016) ( Memento from September 7, 2017 in the Internet Archive )
  6. ↑ Johnston's Archives: List of Known Trans-Neptunian Objects (October 2018)
  7. ↑ M. Brown : How many dwarf planets are there in the outer solar system? (November 2018)