Comets and Asteroids
43 Ariadne is well-placed in Pisces for observing from the UK throughout October
Asteroid 43 Ariadne reaches opposition on 13 October within the wedge formed by the stars representing the rope tying together the two fishes of Pisces. Ariadne’s entire journey this month is contained within this wedge, meaning that the asteroid is well-placed for UK sighting in October.
At the start of the month Ariadne can be found approximately 4° east-southeast of mag. +3.6 Eta (d) Piscium. On 1 October the asteroid has a magnitude of +10.6. This slowly increases over the following days to reach a peak value of +10.3 by 13 October when Ariadne will have moved south and east to lie 5° north of mag. +4.3 Epsilon (¡) Piscium. By 31 October, it sits a little over 3° north of mag. +4.4 Delta (b) Piscium. At the end of the month it will have faded slightly to mag. +10.9.
Ariadne is a siliceous, or stony, type of asteroid (S-type) with a fairly high reflectivity, or albedo, of 27.4%. This means
that 27.4% of incident sunlight is reflected back from its surface. It’s unusual in that one of its dimensions is almost twice that of the others; its triaxial size being 95x60x50km.
It’s the second largest body in the Florian family, a large group of siliceous asteroids in the inner main asteroid belt between the orbits of Mars and Jupiter. Around 4-5% of all main belt asteroids belong to the Florian family. Because of the group’s poorly defined boundaries, and the extreme peripheral location of its largest asteroid, 8 Flora, this asteroid group has also sometimes been referred to the Ariadnean family.
Discovered on 15 April 1857 by English Astronomer NR Pogson, Ariadne orbits the Sun once every 1,194.8 days (3.27 years) with an aphelion distance of 2.6AU and perihelion distance of 1.8AU. Its magnitude swings from a dim mag. +13.4 to mag. +8.8 at favourable oppositions.