Recent studies provide unexpected insights into the population of potentially dangerous asteroids orbiting near Earth.
A team of researchers from the University of Maryland, using the Zwicky Transient Facility (ZTF) telescope, studied a swarm of space debris called the "Taurid stream." This cluster is linked to the Encke comet and appears as meteor showers in October and November.
While this region has long been intriguing due to its potential to harbor hidden asteroids, scientists had not yet been able to accurately assess the risks.
Their findings, presented at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society, are quite reassuring.
According to Quanzhi Ye, the study's lead researcher, the risk of impact by a large asteroid from the Taurids is much lower than feared. Taking advantage of a close passage of this swarm, the team was able to more effectively probe for the presence of potentially dangerous objects.
Until now, researchers feared that this swarm contained a large number of kilometer-sized asteroids, capable of causing significant regional damage if they struck Earth. This type of event recalls the 2013 Chelyabinsk incident, where a 66-foot (20-meter) asteroid injured over 1,600 people in Russia.
Image captured by NASA's Spitzer Space Telescope, showing comet Encke and its trail of debris. Every October, Earth crosses this trail, resulting in the famous Taurid meteor showers.
Credit: NASA/JPL-Caltech/Univ. of Minn. The new observations reveal that there may only be nine to fourteen large asteroids in this swarm. This also questions the size of the parent object that created this stream: probably a body only 6 miles (10 kilometers) in diameter, rather than the previously assumed 62 miles (100 kilometers). This finding offers some relief, while reminding us that constant vigilance is necessary when it comes to asteroids.
The origin of the Taurid stream and its connection to Encke's comet remain a topic for astronomers. Encke, which orbits the Sun in just 3.3 years, is particularly dusty and large for a short-period comet. Researchers believe that this celestial body underwent a major fragmentation in the past and may continue to break apart.
Studying this swarm not only helps to better understand the formation and evolution of small comets and asteroids but also refines planetary defense strategies. The collected data offers broader perspectives on the evolution of objects in the Solar System.
Finally, this research highlights the importance of new technologies, such as the Zwicky Transient Facility telescope, in improving the detection of near-Earth asteroids. Scientists hope to continue their work during the next close encounters with the Taurids, expected in 2025 and 2026.
What is the Taurid swarm?
The Taurid swarm is a cluster of space debris linked to Encke's comet. Each year, Earth passes through this region during its orbit around the Sun, resulting in meteor showers visible mainly in October and November.
The origin of this swarm is associated with the past fragmentation of Encke's comet, which completes a full revolution around the Sun in just 3.3 years. The debris from this comet forms the Taurid swarm.
The Taurids have intrigued scientists due to the possibility that they contain large potentially dangerous asteroids. However, recent research has shown that these objects are fewer and less threatening than previously thought.
This study not only helps assess impact risks for Earth, but it also aids astronomers in better understanding the dynamics of small comets and asteroids.