243 Ida is an asteroid, which has its own moon, Dactyl. Ida has a 31.4 km diameter and its orbital path is situated between Mars and Jupiter. It is an irregular and elongated shaped S-Type asteroid. It was first found by an Austrian astronomer Johann Palisa in 29th September 1884. Ida is known for its craters, shape, and its natural moon Dactyl.
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1. According to the Greek Mythology Ida is a Nymph.
2. Ida was named by a Vienna based industrialist Moriz Von Kuffner.
3. While working in Vienna Observatory from 1874 to 1923, Johann Palisa discovered 122 asteroids. 243 Ida was among those 122 asteroids.
4. 243 Ida is a part of the asteroid belt family called Koronis Family. There are many asteroid families located between Mars and Jupiter.
5. But at present whatever statics we have about this asteroid is based on the observation by Galileo Space Craft.
6. Galileo Spacecraft was launched by Space Shuttle Atlantis on 18th October 1989. In 1993 during its flyby to Jupiter, Galileo captured some high-resolution photographs of 243 Ida. While capturing those astonishing images, Galileo was 10870 kilometers far from Ida.
7. Due to the large distance between the Earth and Ida, it took many days to receive the images in the ground station. After the late download in 1994, a member from Galileo mission Ann Harch revealed Dactyl on 17th February 1994.
8. The irregular shaped Ida is 2.35 times as long as it is wide. Geologically it is divided into two parts, which is joined by a “waist”. This waist part is filled with loose debris.
9. The surface is covered with pulverized rock, called regolith. Most of the regoliths are 50 to 100 meters thick. These rocks are composed of some Silicate minerals- Olivine and Pyroxene.
10. Regoliths are the reason for Ida’s uncertain surface area. The surface area of the Ida is full of craters. Some of them are – Afon, Azzura, Choukoutien.
11. The physical structure of the Ida is divided into two regions- region1 and region2. Region 1 has two ridges- Dorsun and Vienna and region2 are filled with grooves. Most of the grooves are up to 100 m wide and 4km long.
12. This S-Type asteroid has a total mass between 3.65 to 4.99×1016 kg.
13. 243 Ida and its moon Dactyl has equal surface temperature -73 degree Celsius.
14. It takes 4.63 hours to orbit on its won axis. The average distance between Ida and the Sun is 2.862 AU and takes 4.84089 years for a single rotation around the Sun.
15. The Dactyl rotates in the opposite direction that of Ida. Dactyl rotates anti-clockwise and takes 20 hours to rotate the Ida. Dactyl maintains 65km distance from Ida and rotates at the speed of 10m/s.
16. The gravitational force of the Ida is low. The gravitational field of the Ida accelerates 0.3 to 1.1 cm per second square on the surface. Due to its low gravitational force, an astronaut can easily cross the asteroid by jumping from one end to another.
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