Discover the fastest asteroid orbiting our solar system

(CNN) – A newly discovered asteroid is approaching our sun, much closer than the planet itself.
The asteroid, named 2021 PH27, completes an orbit around the Sun every 113 days and approaches our star 20 million kilometers.

This gives this space rock the advantage of having the shortest known orbital period for an asteroid and the second shortest orbit around the Sun after Mercury, which takes 88 days to complete its orbital journey around our star.

Scott Sheppard, an astronomer at the Carnegie Institution for Science, discovered the asteroid in aurora observations by Brown University astronomers Ian Del Antonio and Shenming Fu on August 13. Dell’Antonio, professor of physics, and Fu, a doctoral student, captured the images with the Dark Energy camera installed on the Víctor M. Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory in Chile.

Sheppard surprised different aspects of the asteroid.

The asteroid is one kilometer long, he said, and “there are probably very few asteroids of this size in the inner solar system that we weren’t aware of.”

“2021 PH27 is so close to the Sun that its surface can reach a temperature of 482 degrees Celsius, which is hot enough to melt lead,” Sheppard said in an email. “Given these extreme temperatures, it is unlikely that 2021 will consist of any volatile matter, and most likely will consist of rocks that may contain some minerals such as iron.”

It has an unstable orbit that crosses the orbits of Mercury and Venus on its way around the Sun. Within a few million years, the asteroid’s orbit will likely wipe it out. The rocky portion could collide with Mercury or Venus, or with the Sun itself, or be ejected from its current position in the solar system.

The asteroid is so close to the Sun’s massive gravitational field that it suffers effects on its orbit, Sheppard said.

The newly discovered asteroid is just one of about 20 asteroids from Atera, which are those entirely within Earth’s solar orbit.

Although there are a few known asteroids that come as close to the Sun as 2021 PH27, their orbits are much longer.

“Some of these asteroids contain dust in their orbits, which indicates that asteroids are slowly disintegrating or cracking due to the intense thermal stresses to which these objects are exposed,” Sheppard explained.

A prime example is this Phaethon, the asteroid that behaves like a comet Which creates the Geminid meteor showers that occur in our sky in the month of December every year.

asteroid tracking

But where did this space rock come from? That’s one of the questions Sheppard wants to investigate next, but he has some ideas based on the initial observations.

The asteroid may have broken off from the main asteroid belt between Mars and Jupiter, but Sheppard has not ruled out the possibility that 2021 PH27 is an extinct comet.

“It could be an extinct comet, since comets are known to come from the outer solar system in long, long-duration orbits and interact gravitationally with the inner planets to achieve more circular and shorter-duration orbits that keep them in the solar system inside for extended periods of time,” Sheppard explained. . The inner planets are Mercury, Venus, Earth and Mars.

When this happens, some of the comet’s elements evaporate until it no longer appears to be a comet and only the remnants remain.

Sheppard often searches for things very far in the solar system and beyond. However, it is also important to understand the asteroid population near Earth’s orbit. Near-Earth asteroids can collide with it in the future, but some of them are very difficult to notice because they approach our planet during the day.

“Space within Earth’s orbit has been relatively unexplored until now,” Sheppard said. “It is difficult to see the area towards the sun because of its extreme brightness.”

But the dark energy room has a large field of view, making it a powerful tool for looking for things that might go unnoticed, like 2021 PH27, especially during twilight hours, when the sun goes down and right before you leave.

After Sheppard’s discovery, astronomer David Thoulin of the University of Hawaii measured the asteroid’s location and predicted where it would be the next night. This allowed several telescopes to spot the asteroid from Chile and South Africa on August 14 and 15. These astronomers postponed the observations for their own research in order to help learn more about the asteroid.

“Although telescope time is precious, international nature and a love of the unknown make astronomers very willing to defer their science and observations to pursue new and exciting discoveries like this one,” Sheppard said. “We are very grateful to all of our collaborators who have allowed us to act quickly on this discovery.”

Soon, the asteroid will pass behind the sun and won’t be visible until early 2022. Sheppard is eager to learn more about the asteroid’s composition and origin.

“Where do these inner asteroids come from? Some are main belt asteroids that recently separated, others may be extinct comets, but there may be another group of origin, such as Vulcanoids, which is a hypothetical group of asteroids,” Sheppard said. .