Astronomers predict potentially dangerous comet’s trajectory from meteor shower

Comets have long been considered omens and omens, and it’s easy to understand why. They first appear as faint smears of light in the sky, sometimes quickly disappearing, sometimes brighter than the planets, and accompanied by long, glowing tails. Although they have been observed throughout human history, it was not until the 18th century that astronomers began predicting the return of some comets.

Even today, we cannot predict the return of most comets until they have passed through the inner solar system. If such a comet happens to be heading towards Earth, we won’t know about it until it’s too late. But that may change thanks to observations of a meteor shower.

Comets originate from the Oort cloud, an icy remnant of the birth of our solar system that surrounds the sun as a sphere 100,000 astronomical units in diameter. A close collision with another Oort object or a close pass by the star causes some of these distant chunks of ice and rock to tumble toward the inner solar system. They can come from all directions in the sky, and once they dance near the sun, they may not return for hundreds or thousands of years. Comets with periods longer than 200 years are known as long-period comets, and these comets are the most difficult to predict.

Most long-period comets pose no threat to Earth. Although it may appear bright in the evening or morning sky, its orbit does not cross Earth’s, so there is no danger of a collision. However, some long-period comets may pose a collision threat to Earth. We know this partly because we have encountered comets before and partly because we observe periodic meteor showers.

Showers such as the Geminids, Perseids, and Orionids are caused by the dusty trails that comets leave behind as they cross Earth’s orbit. In these cases, we have even identified the origin comets as Comet Phaeton, Comet Swift-Tuttle, and Comet Halley. However, Swift-Tuttle is the only long-period comet (barely) with an orbital period of 257 years.

These connections between comets and meteor showers were made by first knowing the comet’s orbit and then linking its path to known meteor showers. In principle, you should be able to do the opposite. Identify the path of a meteor shower and use it to search for long-period comets. As new telescopes like the Rubin Observatory become operational, this approach could become a useful tool in looking for collision threats. Recent work on the arXiv preprint server shows how this works.

The research team ran simulations of long-period comets spanning 200 to 4,000 years. They will estimate the dust signatures these hypothetical comets produce and determine whether astronomers can use these signatures to work backwards to determine the origin of comets far from the Sun. started.

In hopes of conducting a high-resolution survey of the sky, the research team assumed that astronomers would be able to observe the sky at the expected resolution of the Rubin Observatory. They found that the orbits of many comets do not produce predictive showers, but in 17 cases it was possible to use the showers to identify comets months or years before they would normally be discovered. It turned out that there is a sex.

To further prove this point, the researchers also looked at a faint meteor shower called ?-Hydrids that appears in early December. The origin of the Sigma Hydrid was unknown until Comet Nishimura appeared in 2023. Once the orbit was determined, astronomers discovered a possible connection to the sigma hydrid shower.

The researchers were able to use known observations of the shower before 2023 to determine the comet’s likely orbit. They found that with a search of the sky like Rubin’s, astronomers could have discovered Nishimura eight months before the actual discovery.