NASA's Lucy spacecraft flew past asteroid 152830 Dinkinesh on Wednesday 1 November 2023, discovering that the asteroid had a binary moon in the process. The Lucy spacecraft, launched from Cape Canaveral on 16 October 2021, was named after the Hominin fossil Lucy, which in turn was named after the Beetles song, Lucy in the Sky with Diamonds; the spacecraft carries a disc made of lab-grown diamonds for its L'TES (Lucy’s Thermal Emission Spectrometer) instrument. Lucy's primary mission is to explore Jupiter's Trojan Asteroids (asteroids permanently located in Jupiter's L₄ and L₅ Lagrange points. The trajectory of the probe was adjusted to make a flyby of 152830 Dinkinesh in January 2023, primarily as a way of testing its instruments on a suitable object.
The spacecraft first spotted the asteroid orbiting the 790 m asteroid at 4.55 pm GMT on 1 November 2023, when it was 430 km from the asteroid, passing it at a speed of 16 000 km per hour. At this time it was thought the second body was a single object roughly 220 m in diameter. However, the spacecraft took a second image looking back at the asteroid at 5.00 pm, revealing the satellite body to be a binary, made up of two similar sized objects in contact with one-another.
While it was once thought that small asteroids lacked sufficient gravitational pull to have satellites, an increasing number have been shown to do so in recent years, and this is now thought to be quite common. Similarly, contact binaries, not predicted until they were discovered, are now fairly frequently observed. This is, however, the first time a moon of a small asteroid has been found to be a contact binary.
Asteroid 152830 Dinkinesh was discovered by the Lincoln Near-Earth Asteroid Research Survey in Socorro, New Mexico on 4 November 1999. It was originally given the designation 1999 VD57, indicating that it was the 1429th object (asteroid D57 - in numbering asteroids the letters A-Z, excluding I, are assigned numbers from 1 to 25, with a number added to the end each time the alphabet is ended, so that A = 1, A1 = 26, A2 = 51, etc., which means that D57 = (25 x 57) + 4 = 1429) discovered in the first half of November 1999 (period 1999 V - the year being split into 24 half-months represented by the letters A-Y, with I being excluded). The longer designation 152830 implies that it was the 152 830th asteroid ever discovered, (these numbers are not assigned immediately, to prevent false sightings and repeat sightings of the same body being numbered). The name 'Dinkinesh' derives from 'Dink’inesh', which is the name given to the Lucy fossil in Amharic (the official language of Ethiopia, where the fossil was discovered), and means 'you are wonderful'. The name was chosen after it was decided that the asteroid would be a target for the Lucy spacecraft, and approved by the International Astronomical Union's Working Group for Small Bodies Nomenclature on 6 February 2023.
.jpg)
152830 Dinkinesh is calculated to have a 1185 day (3.24 year) orbital period, with an elliptical orbit tilted at an angle of 2.09° to the plain of the Solar System which takes in to 1.94 AU from the Sun (194% of the distance at which the Earth orbits the Sun, and some way the orbit of Mars) and out to 2.44 AU (2.44 times the distance at which the Earth orbits the Sun). It is therefore classed as a Main Belt Asteroid.
See also...
Follow Sciency Thoughts on Facebook.
Follow Sciency Thoughts on Twitter.
