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.
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]