Asteroid 16 Psyche reaches opposition in the constellation of Leo, the Lion
Asteroid 16 Psyche reaches opposition on 3 March when it can be found shining at mag. +10.4 in the belly of Leo, the Lion. At 00:00 UT on 1 March, Psyche appears at mag. +10.5 and forms the northeast vertex of an equilateral triangle with mag. +4.6 Chi (χ) Leonis and the mag. +5.0 star 59 Leonis. It subsequently tracks west-northwest, brightening to mag. +10.4 on 2 March, a level it maintains until the 5th. It then starts to dim, ending the month at mag. +11.1. At this time, it will be located 1.5˚ eastnortheast of variable Rho (ρ) Leonis. This star exhibits a small brightness variation between mag. +3.8 and mag. +3.9. Psyche’s position at the end of the month places it around 3˚ to the southwest of the galaxy trio M95, M96 and M105.
Psyche has a diameter of 200km and is thought to be the remnant iron core of a failed planet, a protoplanet. This is a body which formed out of the Solar System’s original protoplanetary disc and had enough mass to undergo its own internal melting and deformation. The result is a massive object, Psyche ranking as one of the ten most massive asteroids known. It’s so massive that its gravitational effect on other asteroids can be used to measure its mass. This has been determined as 2.72 x 10 19 kg.
Psyche’s orbit takes 4.99 years to complete, its passage around the Sun taking place at an average distance of 2.9 AU. It rotates relatively quickly, completing one rotation every 4.2 hours. It is believed to be potato-shaped, measuring 279km x 232km x 189km. Its size and shape were partly calculated by compiling the results of over 100 occultation events involving distant stars.