Sunday 3 February 2019

Asteroid 532 Herculina approaches opposition.

Asteroid 532 Herculina will reach opposition (the point at which it is directly opposite the Sun when observed from the Earth) at 4.48 am GMT on Tuesday 5 February 2019, when it will also be at the closest point on its orbit to the Earth, 1.422 AU (i.e. 1.422 times as far from the Earth as the Sun, or about 212 728 000 km), and be completely illuminated by the Sun. While it is not obvious to the naked eye observer, asteroids have phases just like those of the Moon; being further from the Sun than the Earth, 532 Herculina is 'full' when directly opposite the Sun. As 532 Herculina is only about 225 km in diameter, it will not be visible to the naked eye, but with a maximum Apparent Magnitude (luminosity) of 8.7 at opposition, it should be visible in the Constellation of Leo to viewers equipped with a good pair of binoculars or small telescope.

The position in the sky of 532 Herculina at 4.48 am GMT on Tuesday 5 February 2019, when it will be at opposition. Dominic Ford/In The Sky Online Planatarium.

532 Herculina was discovered on 20 April 1904 by the German astronomer Max Wolf, as originally given the designation 1904 NY, which implies that it was discovered in 1904 and was the 324th asteroid (asteroid NY) discovered after the introduction of a double-lettered designation system introduced in January 1893 (in which AA equalled 1, AB equalled 2, BA equalled 25 etc.). It was later named 'Herculina' by Wolf and given the designation 532, for the 532nd asteroid ever discovered. 

Image of 532 Herculina obtianed with the 6 m BTA Telescope at the Special Astrophysical Observatory in the Caucassus Mountains in the Karachay-Cheressia Republic of Russia in September 2016. Sokova et al. (2016).

532 Herculina has an 1686 day orbital period and an eccentric orbit tilted at an angle of 16.3° to the plane of the Solar System, which takes it from 2.28 AU from the Sun (i.e. 228% of the the average distance at which the Earth orbits the Sun) to 3.26 AU from the Sun (i.e. 326% of the average distance at which the Earth orbits the Sun). As an asteroid that never comes within 1.666 AU of the Sun and has an average orbital distance less than 3.2 AU from the Sun, 532 Herculina is classed as a Main Belt Asteroid. 

The calculated orbit of 532 Herculina. JPL Small Body Database.

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