New Horizons’ Next Flyby Destination MU69 Might Have A Moon Of Its Own

The spacecraft’s upcoming target in the Kuiper Belt is full of surprises, astronomers recently discovered.

Artist’s illustration of the New Horizons spacecraft near the dwarf planet Pluto and its moon Charon.
Edobric / Shutterstock

The spacecraft’s upcoming target in the Kuiper Belt is full of surprises, astronomers recently discovered.

Exciting news for NASA’s New Horizons mission: it seems the probe’s future flyby target — a small, frozen world discovered in 2014 and dubbed MU69 — has more to offer than previously imagined.

An analysis of the latest telescope data on MU69 revealed New Horizons’ target for the New Year’s Day 2019 flyby “holds many surprises” and is “a lot more complex than anyone suspected,” NASA announced.

According to a news release issued earlier this week by the space agency, MU69 might be orbited by another object, potentially a small moon.

“We really won’t know what MU69 looks like until we fly past it, or even gain a full understanding of it until after the encounter,” said Marc Buie, member of the New Horizons science team and astronomer at the Southwest Research Institute (SwRI) in Boulder, Colorado.

“But even from afar, the more we examine it, the more interesting and amazing this little world becomes.”

The new scoop on MU69 comes from the telescope readings recorded by NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) during the occultation on July 10.

Since not much is known about New Horizons’ next destination, astronomers exploited the occultation event in an attempt to discover more about MU69’s motion as it passed in front of a star.

The airborne observatory, which was flying over the Pacific Ocean at the time of the occultation to target MU69’s anticipated location, identified “a very short drop-out in the star’s light,” NASA disclosed.

Astronomers are in the process of analyzing the telescope data, and they suggest the “blip” SOFIA picked up could actually be a moonlet orbiting MU69.

However, before they can be sure that their interpretation is accurate, astronomers first need to analyze the data against the findings of the European Space Agency’s Gaia satellite regarding MU69’s orbit calculations, Buie points out.

Although for now it’s no more than a theory, to be confirmed or disproved when New Horizons finally zooms past the peanut-shaped object on January 1, the prospect that MU69 could have its own moon is, nevertheless, thrilling.

This possibility adds new value to the upcoming mission of the New Horizons spacecraft, already highly anticipated due to MU69’s mysterious appearance.

“The allure of its exploration is becoming stronger and stronger as we learn more and more about it. It’s just fantastic,” remarked Alan Stern, New Horizons principal investigator, also from SwRI.

MU69 is shaping up to be quite an interesting flyby venue. Additional telescope observations, gathered only a week later, revealed the object’s peanut shape could be attributed to MU69 being a pair of like-sized objects orbiting each other, instead of just one bigger object.

The supposition that MU69 has a binary structure started to gain ground after the July 17 stellar occultation, during which five different telescopes set up by the New Horizons team in Argentina picked up crucial data suggesting the spacecraft’s next flyby target could actually be two targets rolled into one.

The latest news about a potential moon orbiting MU69 raises the number to three, at least in theory.

This new possibility that MU69 is, in fact, a binary orbited by a smaller moon could account for the changes in the object’s position from one occultation to the other, Buie explains.

MU69 resides at the edge of our solar system, one billion miles (1.6 billion kilometers) past Pluto. The small peanut-shaped object is only 20 miles (30 kilometers) long. This means that, if MU69 is a binary, each part would only be about nine to 12 miles (15 to 20 kilometers) in diameter.

Located more than four billion miles (6.5 billion kilometers) from Earth, in the Kuiper belt, MU69 is the farthest destination New Horizons has ever gone to, and the most remote world we have ever explored.

Since the January 1 flyby promises to be truly unforgettable, NASA launched a public campaign last month to find a more memorable nickname for MU69, whose official designation is “(486958) 2014 MU69.”