3 Juno

Juno is a large rock in space.

It is a big asteroid. A man found it in 1804.

At first, people thought it was a planet. Later, they learned it was an asteroid. It is very bright. This brightness helps us see it. It is made of stone. It has a strange shape. It also has a big hole on it. This hole came from a crash. Juno stays in a belt of rocks. It is a very special part of space.

Juno is a very large asteroid. It lives in the asteroid belt. A man named Karl Harding found it in 1804.

At first, people thought it was a planet. Later, they learned it was an asteroid. It is one of the largest stony asteroids. We call these S-type asteroids.

Juno is very bright. This is because it has a high albedo. Albedo is a word for how much light a surface reflects. This brightness helped people find it early.

Juno has a very strange path around the Sun. This path is called an orbit. Its orbit is very stretched out. This is called high eccentricity. Because of this, Juno gets very close to the Sun. It also moves very far away. Juno has an irregular shape. It is not a perfect circle. It also has a large crater. A crater is a big hole made by a crash. This hole is about 100 km wide.

The name Juno comes from a Roman goddess. Her symbol is a scepter with a star on top.

Juno is a huge asteroid located in the asteroid belt. It is one of the most important objects in that region. In fact, it contains about 1% of the total mass of the whole belt.

Juno is also one of the two largest stony asteroids, which scientists call S-type asteroids. It is the second most massive of this type, following 15 Eunomia. Even with its size, it only has 3% of the mass of Ceres. Ceres is the largest asteroid in our solar system.

Juno has a very interesting way of moving around the Sun. Its path is called an orbit. This orbit has high eccentricity, which means it is very stretched out rather than being a circle. Because of this shape, Juno travels very close to the Sun at one point. It also moves very far away at another point. Its orbit is also tilted at an angle of about 12 degrees. This path is even more stretched than the orbit of the dwarf planet Pluto.

People first found Juno on September 1, 1804. A German astronomer named Karl Ludwig Harding discovered it. At that time, people actually thought Juno was a planet. It was grouped with Ceres, Pallas, and Vesta as a new planet. However, more asteroids were found later on. Because of this, scientists reclassified Juno as an asteroid during the 1850s.

Juno is a very bright object in the sky. This brightness comes from its high albedo, which is a measure of how much light a surface reflects. Because it reflects so much light, it can appear brighter than Neptune or Titan. This helped astronomers find it before other larger asteroids like Hygiea or Europa. Some researchers even used the Hale Telescope to study it. In 2004, they reported that its average radius is about 135.7 kilometers.

We can learn a lot about Juno by looking at its surface. It has an irregular shape and a large crater. This crater is about 100 kilometers wide. It was likely made by a recent impact from another object. Scientists also study how Juno blocks the light of stars. This is called an occultation. The first time this happened with Juno was on February 19, 1958.

Juno is a massive asteroid located within the asteroid belt. It is a significant object in our solar system. Juno contains approximately 1% of the total mass of the entire asteroid belt.

It is categorized as an S-type asteroid, which means it is a stony object. Among these stony asteroids, Juno is the second most massive. Only 15 Eunomia is more massive in this specific category. Despite its size, Juno only has 3% of the mass of Ceres. Ceres is the largest asteroid in the belt.

The movement of Juno follows a very specific path called an orbit. This orbit is characterized by high eccentricity. Eccentricity describes how much an orbit deviates from a perfect circle. Juno's orbit is very stretched out. This shape is even more extreme than the orbit of the dwarf planet Pluto. The orbit is also tilted at an inclination of about 12 degrees. Because the path is so elliptical, Juno's distance from the Sun changes greatly. At perihelion, it moves closer to the Sun than Vesta. At aphelion, it moves further away than Ceres.

Juno's physical properties make it stand out to astronomers. It has an unusually high albedo. Albedo is a measure of how much light a surface reflects. Because it is so reflective, Juno can appear very bright. At a favorable opposition, it can reach a magnitude of +7.5. This makes it appear brighter than Neptune or the moon Titan. This brightness is why it was discovered before larger asteroids like Hygiea or Europa. However, at most oppositions, it only reaches a magnitude of +8.7. At that brightness, it requires binoculars to see.

History shows that our understanding of Juno has changed over time. Karl Ludwig Harding discovered Juno on September 1, 1804. He was a German astronomer. At the time of discovery, Juno was considered a planet. It was grouped with Ceres, Pallas, and Vesta. As more asteroids were found, scientists changed their classification. During the 1850s, Juno was reclassified as an asteroid. The name comes from Juno, the highest Roman goddess. The astronomical symbol for Juno is a scepter topped by a star.

Scientists have used many tools to study the surface of Juno. In 2004, researchers used the Hale Telescope for Mid-Infrared Asteroid Spectroscopy. This is a method called MIDAS. These studies helped determine its average radius is about 135.7 kilometers. Infrared images show a large crater on the surface. This crater is approximately 100 kilometers wide. It is the result of a geologically young impact. This impact likely created a dark feature on the asteroid.

Astronomers also study Juno through a process called occultation. An occultation happens when an object passes in front of a star. Juno was the first asteroid for which an occultation was observed. This occurred on February 19, 1958, when it passed in front of star SAO 112328. Another major event happened on December 11, 1979. During that event, Juno occulted the star SAO 115946. Eighteen different observers registered that event. More occultations were recorded as recently as July 2013.

Juno is also linked to other celestial bodies and materials. It is the main body in the Juno family of asteroids. Spectroscopic studies suggest Juno could be the progenitor of chondrites. Chondrites are common stony meteorites. These meteorites are composed of iron-bearing silicates like olivine and pyroxene. The mass of Juno has even been estimated using radio signals. These signals come from spacecraft near or orbiting Mars. Scientists measured tiny perturbations, or changes, in the motion of Mars. These changes were caused by the gravitational pull of Juno.