2015 AJ ₂₈₁

Asteroid 2015 AJ 281
Properties of the orbit ( animation ) Epoch:  April 27, 2019 ( JD 2,458,600.5)
Orbit type	DO (E SDO ) or CKBO ( «Hot» ), «Distant Object»
Major semi-axis	43,343  AU
eccentricity	0.131
Perihelion - aphelion	37.672 AU - 49.013 AU
Inclination of the orbit plane	26.8 °
Length of the ascending node	256.2 °
Argument of the periapsis	6.8 °
Time of passage of the perihelion	January 26, 2079
Sidereal period	285 a 4.2 M
Mean orbital velocity	4.487 km / s
Physical Properties
Medium diameter	approx. 468 km
Albedo	0.07-0.09
Absolute brightness	5.0 - 5.3 mag
history
Explorer	ESO Pan-STARRS
Date of discovery	March 25, 2011
Another name	2011 FW 62
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.

2015 AJ ₂₈₁ is a large trans-Neptunian object in the Kuiper Belt , which is classified as an extended Scattered Disc Object (DO) or as a Cubewano in terms of railway dynamics . Because of its size, the asteroid is a dwarf planet candidate .

discovery

2015 AJ ₂₈₁ was tracked down on March 25, 2011 at the European Southern Observatory (ESO) ( Chile ) and the planetoid was given the original designation 2011 FW ₆₂ , but it was then lost again. He was one of the 6 January 2015 astronomers as part of the Pan-STARRS -project with the 1.8-meter Ritchey-Chretien telescope (PS1) at Haleakala Observatory ( Maui rediscovered) and received by the IAU , the more recent designation 2015 AJ ₂₈₁ , which means that the first discovery was treated as a pre-discovery.

After its discovery, AJ _{281 could be identified} in photos up to February 25, 2010, which were also taken as part of the Pan-STARRS program, and thus its observation period was extended by four years in order to calculate its orbit more precisely. In September 2018, there were a total of 76 observations over a period of 8 years. The last observation so far was again carried out in January 2018 at the Pan-STARRS telescope. (As of February 28, 2019)

properties

Orbit

2015 AJ ₂₈₁ orbits the sun in 285.35 years on a slightly elliptical orbit between 37.67  AU and 49.01 AU from its center. The eccentricity of the orbit is 0.131, the orbit is inclined at 26.80 ° to the ecliptic . The planetoid is currently 42.65 AU from the Sun. He will next pass through perihelion in 2079, so the last perihelion should have occurred in 1793.

Marc Buie ( DES ) classifies the planetoid as an extended SDO (ESDO or DO ), while the Minor Planet Center classifies it as a non-SDO and generally as a “distant object” . The Johnston's Archive, however, lists him as Cubewano , whereby he would belong to the "hot" classic KBO in terms of rail dynamics .

size

A diameter of around 468 km is currently assumed, based on a reflectivity of 7% and an absolute brightness of 5.3  ^m . Assuming a diameter of 468 km, this results in a total surface of around 688,000 km ² . The apparent magnitude of 2015 AJ ₂₈₁ is 21.39  ^m .

Since it can be assumed that 2015 AJ ₂₈₁ is in hydrostatic equilibrium due to its size and therefore has to be largely round, it should meet the criteria for classification as a dwarf planet . Mike Brown believes that it is in 2015 AJ ₂₈₁ to possibly is a dwarf planet.

Provisions of the diameter for 2015 AJ ₂₈₁

year	Dimensions km	source
2018	443.0	Johnston
2018	468.0	Brown
The most precise determination is marked in bold .

See also

• List of trans-Neptunian objects
• List of dwarf planets of the solar system
• List of asteroids
• List of moons from asteroids

Web links

• How many dwarf planets are there in the outer solar system? Current list of the largest TNOs from Mike Brown
• Free the dwarf planets! Mike Brown's column on the IAU and the dwarf planets regarding their classifications (23 August 2011)

Individual evidence

1. ^ ^{A b} Marc W. Buie : Orbit Fit and Astrometric record for 15AJ281 . SwRI (Space Science Department). Retrieved February 28, 2019.
2. ↑ ^{a b c} Wm. R. Johnston: List of Known Trans-Neptunian Objects . Johnston's Archives. October 7, 2018. Retrieved February 28, 2019.
3. ↑ ^{a b c} 2015 AJ281 at the IAU Minor Planet Center (English) Retrieved on February 28, 2019.
4. ↑ v ≈ π * a / period (1 + sqrt (1-e²))
5. ↑ 2015 AJ281 in the Small-Body Database of the Jet Propulsion Laboratory (English). Retrieved February 28, 2019.
6. ↑ MPC : MPEC List Of Centaurs and Scattered-Disk Objects . IAU . Retrieved February 28, 2019.
7. ↑ 2015 AJ281 in the database of the "Asteroids - Dynamic Site" (AstDyS-2, English).
8. ↑ ^{a b} Mike Brown : How many dwarf planets are there in the outer solar system? . CalTech . November 12, 2018. Retrieved February 28, 2019.