A North American team of astronomers announced last Monday (23) the discovery of the closest asteroid to the Sun ever observed. With a kilometer in diameter, the body passes just 20 million kilometers from our star-king, or the equivalent of just over a tenth of the distance between Earth and the Sun.
The orbit is quite elongated, so the average distance is a little longer, at about 70 million kilometers. For comparison, the planet Mercury is about 58 million kilometers from the Sun. The asteroid, dubbed 2021 PH27, gets so close to the star every 113 days that its surface temperature can reach 500 degrees Celsius, enough to melt lead .
Remember that the asteroid’s orbit is very far from Earth, so there is no chance of collision with our planet.
The discovery was made for the first time on August 13 this year. Astronomers Ian Dell’antonio and Shenming Fu, from Brown University, took advantage of the evening twilight to look for this type of object, deviating somewhat from the Blanco Observatory’s primary mission of searching for clusters of distant galaxies.
The time is perfect for looking for asteroids close to the Sun, like 2021 PH27. After all, at midnight the Earth is facing the other way, meaning the telescope is pointing away from the Sun. At the same time, observations are more difficult as the sky is still relatively clear.
Still, scientists were able to detect the asteroid and perform an initial measurement of its position and orbit. Using this data, astronomer David Tholen of the University of Hawaii was able to predict its position the following night, again observing the asteroid and confirming its unusual configuration.
The discovery is interesting for us to learn a little more about the formation of our Solar System. After all, asteroids formed at much greater distances, between the orbits of Mars and Jupiter.
One hypothesis would be a gravitational shift. By passing close to a planet with much more mass and gravity, the 2021 PH27 orbit could be shifted to get closer to the Sun.
However, another important piece of evidence for the object’s origin is its 32-degree tilt. This means that the newly discovered body is not orbiting in the same plane as the other planets, but in an inclined plane in relation to the other bodies in the Solar System.
This means that 2021 PH27 could be an extinct comet, formed on the outskirts of the Solar System and captured in this orbit when passing close to a planet.
These are interesting hypotheses, which will be investigated more carefully based on the determination of their chemical composition, with further observations. These new studies will then allow us to know a little more about the history of 2021 PH27 and its origins.
As I always say here, the best discoveries are the ones that generate the most new scientific questions.