Kuiper Belt Objects, also known as KBOs,
are icy remnants from the early solar system,
located beyond Neptune.
There are over 3,000 cataloged KBOs so far,
but scientists estimate there could be hundreds of thousands more,
each over 10 miles in diameter.
The largest KBO is the dwarf planet Pluto.
While these distant objects typically don’t
form their own systems, researchers
have likely identified a stable trio of
icy space rocks in the Kuiper Belt.
This discovery of the Altjira system,
made using data from the Keck Observatory in Hawaii,
and NASA’s Hubble Space Telescope
could mark only the second three-body system
found in the region.
If confirmed, the Altjira system hints
at the possibility of more such triple systems
awaiting discovery.
These formations challenge the idea
that collisions in the crowded Kuiper Belt
produce such groups.
Instead, they support the theory that
triplets like these form directly
through the gravitational collapse of material
in the solar system’s early disk,
around 4.5 billion years ago.
While stars are known to form as pairs or triples
through gravitational collapse,
researchers are still investigating whether
this process applies to Kuiper Belt objects.
The Altjira system lies 3.7 billion miles away,
or 44 times the distance between Earth and the Sun.
Only a fraction of a pixel on Hubble’s camera
separates the two innermost members.
Studying such distant, faint objects
orbiting so close together requires patience and persistence.
Using Hubble and Keck, scientists observed
the system with data spanning over 17 years.
This long-term study shows us
Hubble’s incredible value to astronomy.
After more than 30 years in space,
Hubble can revisit objects
days, weeks, months, or even decades later,
helping us uncover the mysteries
of the universe, one observation at a time.
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