Discovery [1] [2] | |
---|---|
Discovered by | Dark Energy Survey |
Discovery site | Cerro Tololo Obs. |
Discovery date | 17 January 2015 (first observed only) |
Designations | |
2015 BP519 | |
Caju (nickname) [a] | |
TNO
[3] ·
ESDO
[4] ·
ETNO distant [2] | |
Orbital characteristics [3] | |
Epoch 27 April 2019 ( JD 2458600.5) | |
Uncertainty parameter 5 | |
Observation arc | 3.22 yr (1,176 d) |
Aphelion | 820 AU |
Perihelion | 35.2 AU |
428.03 AU | |
Eccentricity | 0.9178 |
8856 yr (3,234,488 d) | |
358.39 ° | |
0° 0m 0.36s / day | |
Inclination | 54.125° |
135.11° | |
≈ 7 September 2058
[5] ±1 month | |
348.37° | |
Physical characteristics | |
Mean diameter | 524
km (est.)
[6] 584 km (est.) [4] |
0.08 (assumed)
[6] 0.09 (assumed) [4] | |
21.5 | |
4.4 [2] [3] | |
2015 BP519, nicknamed Caju, [a] is an extreme trans-Neptunian object from the scattered disc on a highly eccentric and inclined orbit in the outermost region of the Solar System. [7] It was first observed on 17 January 2015, by astronomers with the Dark Energy Survey at Cerro Tololo Observatory ( W84) in Chile. [1] [2] It has been described as an extended scattered disc object (ESDO), [4] and fits into the group of extreme objects that led to the prediction of Planet Nine, and has the highest orbital inclination of any of these objects. [a]
2015 BP519 orbits the Sun at a distance of 35.2–821 AU once every 8856 years (3,234,488 days; semi-major axis of 428 AU). Its orbit has an exceptionally high eccentricity of 0.92 and an inclination of 54 ° with respect to the ecliptic. [3] This makes it a probable outlier among the known extreme trans-Neptunian objects. [3] [8]
2015 BP519 fits into the group of extreme trans-Neptunian objects that originally led to the prediction of Planet Nine. [a]: 13 The group consists of more than a dozen bodies with a perihelion greater than 30 AU and a semi-major axis greater than 250 AU, with 2015 BP519 having the highest orbital inclination of any of these objects. [a] Subsequently, unrefereed work by de la Fuente Marcos (2018) found that 2015 BP519's current orbital orientation in space is not easily explained by the same mechanism that keeps other extreme trans-Neptunian objects together, suggesting that the clustering in its orbital angles cannot be attributed to Planet Nine's influence. [8] However, regardless of the current direction of its orbit, its high orbital inclination appears to fit into the class of high-semi major axis, high-inclination objects predicted by Batygin & Morbedelli (2017) to be generated by Planet Nine.
The body's observation arc begins with a precovery taken on 27 November 2014 by astronomers with the Dark Energy Survey using the DECam instrument of the Víctor M. Blanco Telescope at Cerro Tololo Inter-American Observatory in Chile. [2] Its discovery was reported in a paper published by Dark Energy Survey astronomers in 2018. [7]
According to Michael Brown and the Johnston's archive, 2015 BP519 measures 524 and 584 kilometers in diameter based on an assumed albedo of 0.08 and 0.09, respectively. [4] As of 2018, no rotational lightcurve of has been obtained from photometric observations. The body's rotation period, pole and shape remain unknown. [3]