New Year’s Day was especially exciting this year as New Horizons flew by its latest target, Ultima Thule. Previously, scientists did not have enough information on this tiny world, but even a few weeks after the flyby, New Horizons has sent valuable data about this world and how it may have formed. Over the course of the year, New Horizons will continue beaming data back to Earth to help us understand the origins of the Kuiper Belt and the objects contained within. However, let’s look at what discoveries about Ultima Thule were made this month so far.
New Horizons was awakened a few months ago to help prepare for the flyby on January 1st, 2019. Over the course of the latter half of December, NASA began collecting early snapshots of Ultima Thule, and they were able to deduce that Ultima Thule may be a contact-binary or binary system. A contact binary is an object that is comprised of two original objects combined by the force of gravity. However, a binary system has objects that rotate around a gravitational point called a barycenter. From the first clear images it was clear that Ultima Thule is in fact a contact-binary world shaped as a snowman. The big lobe is called Ultima, while the smaller is called Thule. (1)
In addition to the first images, New Horizons collected basic information about the size and characteristics of Ultima Thule. In total the world is 31 kilometers is length and 19 kilometers in width at the largest lobe. The smallest lobe is only 9 kilometers wide (1). Scientists also looked for any satellites or rings around Ultima Thule, but there were none to be found. There was also no evidence of an atmosphere. Finally, the color of this world is of a reddish tint, which was accurate to the predictions made earlier in 2018 as well as to the general characterizes of Kuiper Belt Objects. Both lobes of Ultima Thule are the same color, so these two objects must have formed near each other. (2)
More recently, the team at NASA compiled a movie of the images collected by New Horizons as it approached Ultima Thule. You can see that movie down below. The first image captured by New Horizons had a resolution of 1.5 miles per pixel, and the last image captured had a much clearer resolution of 0.08 miles per pixel. By looking at these pictures it is possible to determine that Ultima Thule has a rotational period of 16 hours. Since New Horizons was flying by perpendicular to the rotation axis of Ultima Thule it was easy to determine the rotation period. The spacecraft flew by at just 2200 miles away from Ultima Thule, so we may get more detailed pictures in the future. (3)
New Horizons continues to fly on deep into the Kuiper Belt. Ultima Thule was discovered after the Pluto flyby, so it may be possible that the team at NASA will look to find another target to visit within the next few years. Keep an eye out on the NASA website for more information about Ultima Thule as data gets released throughout the year.