New Horizons team releases first stereo image of Ultima Thule
At the most recent press conference of the Ultima Thule flyby, NASA’s New Horizons team released the first stereo image of the Kuiper Belt object (KBO), enabling viewers wearing 3D glasses to see its shape. Stereoscopy, also known as stereoscopic imaging, shows depth as opposed to a flat image.
Panelists at the event, held at JHUAPL on Thursday, January 3, at 2 PM, included New Horizons principal investigator Alan Stern of the Southwest Research Institute (SwRI), co-investigator Mark Showalter of the SETI Institute, co-investigator Leslie Young of SwRI, co-investigator Silvia Protopapa of SwRI, and co-investigator Paul Schenk of the Lunar and Planetary Institute (LPI).
Stern reported that the spacecraft, which conducted its last observations of Ultima Thule on Thursday, has already traveled three million miles beyond its second target into the Kuiper Belt. Transitioning out of flyby mode, the probe is now conducting distant observations of various KBOs and studying its Kuiper Belt environment.
Analysis of the flyby data returned so far has revealed no evidence for ring particles or moons one mile in diameter or larger orbiting Ultima Thule, Showalter said. Mission scientists are continuing the search because the presence of one or more satellites during the time of Ultima’s formation would play a crucial role in Ultima’s formation by having slowed the rotation of the two lobes that eventually came together to form the KBO. Their search will not be completed until additional images are downloaded from the spacecraft.
The presence of a moon would also help scientists determine Ultima Thule’s mass and density, allowing them to identify the composition of its interior.
No evidence has been found to indicate the KBO has an atmosphere. Mission scientists do not expect to see a slowdown of the solar wind, the stream of charged particles coming from the Sun, at Ultima Thule. An atmosphere would cause such a slowdown.
“We do not expect to be seeing any atmosphere coming off of the solar wind to detect dust,” Young said, reporting on observations of the spacecraft’s ultraviolet ALICE instrument and Student Dust Counter (SDC). “We looked back at Ultima Thule with our imagers, with MVIC and LORRI. Those are not going to come back for a few weeks, but when they do, we will look to see if we see dust in-trained on a coma the way you would see dust in an outburst from a comet.”
Ultima Thule’s two lobes are nearly the same reddish color, making them typical of most objects in the region, known as the cold classical Kuiper Belt. KBOs in this area have nearly circular, low-inclination orbits because they were never perturbed by the solar system’s gas giant planets, Protopapa said.
“Cold classical Kuiper Belt Objects are relatively redder than the rest of the population [of KBOs],” Protopapa said.
Ultima’s color indicates it is a good representative of this class of objects, meaning details scientists learn regarding its composition will yield greater understanding of this entire population of objects.
The fact that both lobes of Ultima are nearly identical in color supports scientists’ hypothesis that the KBO is the result of a merger of two objects that accreted in the region.
A “movie” created from the stereo image shows Ultima Thule’s rotation and reveals some of its topography, Schenk said. Brighter materials seems to be concentrated in lower regions or troughs, indicating surface material may be moving downward from higher terrain such as ridges.
A large impact crater appears to be visible on the far side of the upper lobe as a dark spot.
“We do need to be careful about interpreting images like this because these are basically equivalent to full Moon images that we see from Earth, where shadows and textures are washed out, and we see the albedo variations. Some of these markings could be ridges, but we won’t know for sure until the subsequent images are downloaded.”
Stern also acknowledged three artists who served as science team collaborators, creating art to represent the mission and its findings.
“We use art to help illuminate the science,” Stern said. “I want to highlight the work of three members of our science team, who are actually doing just that this week to help us explore what all this data means.”
Kean created hand sketches of Ultima Thule, imagining the types of processes occurring on its surface based on the actual data that has been returned. Gabasova sketched individual members of the New Horizons team alongside drawings that show the specific areas on which they are working. Kinczyk made a three-dimensional clay model of Ultima featured at both Wednesday’s and Thursday’s press conferences.
Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.