420356 Praamzius

420356 Praamzius

Discovery
Discovered by	K. Černis R. P. Boyle
Discovery site	Vatican Advanced Technology Telescope (Mount Graham Obs.)
Discovery date	23 January 2012
Designations
MPC designation	(420356) Praamzius
Named after	Praamžius (Lithuanian mythology)
Alternative designations	2012 BX85
Minor planet category	TNO  · distant  (near-3:5 resonance)
Orbital characteristics
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 3
Observation arc	13.08 yr (4,778 days)
Aphelion	43.030 AU
Perihelion	42.529 AU
Semi-major axis	42.779 AU
Eccentricity	0.0059
Orbital period (sidereal)	279.81 yr (102,200 days)
Mean anomaly	188.89°
Mean motion	0° 0m 12.6s / day
Inclination	1.0952°
Longitude of ascending node	314.25°
Argument of perihelion	352.52°
Physical characteristics
Dimensions	202 km
Apparent magnitude	21.89–22.13
Absolute magnitude (H)	5.7

420356 Praamzius, provisional designation 2012 BX₈₅, is a trans-Neptunian object and possible dwarf planet in the Kuiper belt, approximately 200 kilometers in diameter. It was discovered on 23 January 2012, by astronomers Kazimieras Černis and Richard Boyle with the Vatican's VATT at Mount Graham Observatory in Arizona, United States. The object was named after the chief god Praamžius from Lithuanian mythology.

Orbit

Praamzius has the second-lowest eccentricity of any trans-Neptunian object (TNO), after 2003 YN₁₇₉. Praamzius orbits near the 3:5 resonance with Neptune, but not exactly on it, with both its period and orbital radius being slightly too large to fit an exact 3:5 ratio. This could be due to their apparent relationship being merely coincidental, and Praamzius actually being a typical non-resonant cubewano, an artefact of an orbit actually at the extreme end of a librating cycle centred on 3:5 (and oscillating between other seemingly non-resonant values either side of it), or due to it exhibiting some more exotic resonance such as 10:17 or 13:22 which are better fits for the observations obtained so far.

However, it is difficult at this point to determine which of those possibilities is the truth, as although a relatively large number of observations of Praamzius have been obtained considering its size and position and suggest a fairly circular, stable orbit, the data is still not rich or accurate enough to pin it down. The current best estimate rates an Uncertainty Parameter of U = 3, or about 0.327 to 1.400 arc-minutes of possible drift per decade, and over several of its approximately 28-decade orbits (9.15 to 39.20 arcmin uncertainty per orbit) the cumulative error thereby suggested is large enough that all of the above scenarios are entirely possible.

Discovery

This TNO was discovered on 23 January 2012, with precovery observations accepted by the Minor Planet Center dating back to December 2011, with further potential observations dating to 2004 that have yet to be accepted.

Praamzius is one of the most recently discovered minor planets that have been given a numeric designation, most likely because of the large number of observations, on average about one every 10 days, since it was discovered. Most observations were made by the Vatican Advanced Technology Telescope on Mount Graham, Arizona, the discovery site.

Physical characteristics

Analysis of precovery observations of Praamzius from 2002, 2003, 2004, and 2007, show that it is probably one of the reddest objects in the Solar System, being more than 1.5 magnitudes fainter measured in the G (green) filter than the R (red) filter.

Naming

This minor planet was named after Praamžius (an epithet of Dievas), the Lithuanian mythological god of the sky, peace, and friendship. The official naming citation was published by the Minor Planet Center on 22 February 2016 (M.P.C. 98717).

External links

• 420356 Praamzius at the JPL Small-Body Database