Back in 2015, the skull-shaped asteroid officially known as 2015 TB145 flew by Earth aptly during Halloween 2015.
Come November 2018, it's expected to approach Earth once again.
Skull-Shaped Asteroid Of 2015 To Return
Astronomers and other experts worldwide, including NASA, examined 2015 TB145 when it first came near Earth in 2015.
Now, the researchers say it will be at a distance of 105 times the average lunar distance when it comes back for the next flyby, which is farther away than in the previous encounter.
Despite that, astrophysicist of the Institute of Astrophysics of Andalusia Pablo Santos-Sanz believes that they will still get lots of info about the Halloween asteroid.
"Although this approach shall not be so favourable, we will be able to obtain new data which could help improve our knowledge of this mass and other similar masses that come close to our planet," he told Phys.org.
The Halloween Asteroid
Astronomers in Hawaii first spotted 2015 TB145 back in October 2015. Needless to say, it made rounds online not only because of its close proximity to Earth but also its uncanny resemblance to a human skull.
At the time, it came as close as 486,000 kilometers or 300,000 miles away, which is approximately 1.3 times the distance to the moon. As for its size, it's between 625 meters and 700 meters or 2,050 feet and 2,296 feet, and its shape is a "slightly flattened ellipsoid."
According to Santos-Sanz, the rotation period of the asteroid — or put differently, the length of its day — is 2.94 hours, but he also adds that it's possibly 4.78 hours, a finding that's consistent with their data.
More than that, it also has a low reflectivity of 5 percent to 6 percent, or in other words, it can reflect only 5 percent to 6 percent of sunlight. Santos-Sanz explains that this means it's really dark, saying that it's just slightly more reflective than charcoal.
The experts believe that the Halloween asteroid is an extinct comet that no longer has volatile compounds because it orbited the sun too many times already.
It's also worth mentioning that asteroids are typically rocky and metallic, while comets are mostly made up of ice and rock. Aside from those factors, they are distinguished by their orbit as well, but making a distinction between the two is sometimes difficult.
That won't be the last time 2015 TB145 will pay Earth a visit, as it's expected to come back again around Halloween in 2088. It's estimated to approach Earth with a distance of roughly 20 lunar distances then.
The study and findings are published in the journal Astronomy & Astrophysics in February.