Phaethon, A Fascinating Asteroid Near Earth

Phaethon, an asteroid located near Earth which was discovered in 1983, continues to be a topic of intrigue and fascination among astronomers because of its unusual orbit. Now, an international team of researchers have reportedly carried out an in depth analysis of the interesting space rock, and created a model that shows the asteroid's thermophysical parameters, spin state and orbit.

Phaethon is an Apollo asteroid, which indicates asteroids that cross Earth and can sometimes get too close for comfort. However, astronomers also feel that Phaethon is part of the Pallas group of asteroid. Interestingly, the Phaethon space rock goes nearer the sun compared to any other known asteroid, and its perihelion (the term given to an object's nearest distance to the sun during orbit) is about 0.14 AU or 21 million kilometers.

Astronomers believe that Phaethon is the originator of the Geminid meteor shower that is experienced every year in the middle of December. Therefore, scientists are trying to find out any activity associated with the asteroid that leads to the ejection of dust particles from its surface. However, detecting such an occurrence has been challenging due to the asteroid's close orbit of the sun as well as small elongation. "Phaethon's elongation is rather small, thus its light curves have small amplitudes of about 0.1 magnitude," said Josef Hanuš, one of the researchers from the team observing the asteroid. However, Hanuš is working on the setback by studying 55 light curves of Phaethon gathered from the years 1994 to 2015, as well as 29 newer light curves.

After studying the light curves, the astronomers were able to create a shape model of the asteroid, which suggests that its size is about 5.1 kilometers and the sidereal rotation period of the rick takes 3.6 hours. Apart from shape and size, the scientists were also able to calculate Phaethon's macroscopic surface roughness, geometric visible albedo and thermal inertia.

Phaethon is of particular importance to researchers at the moment because it will make a near approach to our planet in 2017, at a distance of around 0.069 AU or 10 million kilometers. The recently developed model will subsequently be useful for making more studies during the flyby.