2012 VP 113
“Biden”Planet 9 2015 TG 387
“The Goblin”
SednaNeptune100 AUKuiper
BeltUranusTop down view46 ASTRONOMYBut FarOut isn’t the only
world that might help point
the way to Planet Nine. In
October 2018, the researchers
announced the confirmation
of another distant discovery
called 2015 TG 387 , which, in
the spirit of
Halloween, they
nicknamed The
Goblin.
Though the
200-mile-wide
(320 k m)through the sky. “You
need a year-long arc on it to
actually get the orbit down,”
Sheppard says. And because
they don’t have a year’s worth
of data for FarOut yet, he
says, “we need another obser-
vation in November [2019] to
actually get a reliable orbit.”
At the time of this
writing,
Sheppard is
eagerly await-
ing the new
November
data.However, Sheppard
stresses that FarOut doesn’t
serve as evidence for Planet
Nine just yet. Because FarOut
is so, well, far out, it’s very
difficult to pin down its orbit.
This makes it tough to tell
whether the new find is actu-
ally a member of the unique
group of TNOs that hint at
the existence of Planet Nine,
or if it’s just a run-of-the-mill
object in a relatively boring,
albeit distant, orbit.
Although Sheppard and
his team are already pretty
confident about FarOut’s
speed (and therefore its dis-
tance), in order to confirm
FarOut’s orbital path,
they must first col-
lect more images
of it movingicy rock was first seen
about 80 AU away, it has a
particularly eccentric orbit,
which means it swings excep-
tionally far from the Sun.
“The Goblin’s orbit is very
large. It has a semimajor axis
of some 1,000 AU,” Sheppard
says, “meaning it takes some
40,000 years to go around the
Sun once.”
Because of the time it
takes The Goblin to complete
a single orbit, the team
required three years of obser-
vations after its initial discov-
ery in 2015 to determine its
exact path through the sky.
But once they pinned it
down, they learned the eccen-
tric TNO comes to perihelionScott Sheppard
and Chad Trujillo
won the 2019
Farinella prize for
their work
exploring and
characterizing objects
in the outer solar system.
EUROPLANET/G. MANTOVANIMAPPING A
MYSTERIOUS WORLD