Astronomers have been closely monitoring the near-Earth asteroid known as Phaethon and believe they may have finally cracked the mystery of why this asteroid reflects light in such an odd way and has a blue hue to it.
According to Phys.org, astronomers from Seoul National University, the National Astronomical Observatory of Japan (NAOJ), Chiba Institute of Technology and other international universities have conducted research on the asteroid using Japan’s 1.6-m Pirka Telescope at Nayoro Observatory to analyze the polarization of light taking place on Phaethon and have published a new study based on their observations.
Phaethon was originally discovered back in 1983 and on December 16, 2017 it whizzed past Earth just 6.4 million miles away, which is the closest it will get to our planet until the year 2093 rolls around. With the asteroid so close last year, astronomers were able to determine that in the center of Phaethon there was a massive void.
After monitoring the way this asteroid reflects light after observing it at different angles, the new study suggests much less light may be reflected from Phaethon’s surface than previously speculated.
There could be numerous reasons for this to occur and may include the presence of an unknown material lurking on the asteroid, with the material extremely porous. The surface of Phaethon may also be quite dark, which is another plausible reason for the lack of light reflected off its surface.
— Phys.org (@physorg_com) June 29, 2018
As the Daily Mail reports, when there is light reflected off the surface of an asteroid and it bounces off another area of it before astronomers can view the light, having light scattered across more than one surface would cause highly polarized light, according to Dr. Ito, the head astronomer of the latest research.
“If the albedo is lower than previously thought, that would reduce the effectiveness of multiple scatterings so that strongly polarized light that has only been reflected a single time would dominate.”
When Phaethon is at its closest to the sun, its surface is capable of reaching temperatures of 1,000 degrees Celsius. This could cause part of the surface of the asteroid to form rough grains.
The DESTINY+ probe will be launched by the Japan Aerospace Exploration Agency in 2022 and will be snapping pictures of Phaethon as it flies by so that astronomers can catch a closer glimpse of this asteroid’s geology and get a better idea about what its surface actually looks like, which would give a clear picture of why it reflects light in the way that it does.
The new research on the polarization of light on the asteroid Phaethon has been published in Nature Communications.