A mysterious new planet has been discovered on the far side of Neptune – but a unique characteristic of its orbit has got scientists puzzled.
The new planet has been christened “Niku” – the Chinese word for rebel. The reason? Because according to observation it has a retrograde orbit that means it rotates in the opposite direction to the sun’s rotation.
more…
“Niku is small – experts believe it has a diameter of 200km (120 miles) across.”
So … not a planet.
CrazyNeutrino said:
Mysterious planet spotted in the outer reaches of our solar system – and it’s orbiting the sun in the wrong directionA mysterious new planet has been discovered on the far side of Neptune – but a unique characteristic of its orbit has got scientists puzzled.
The new planet has been christened “Niku” – the Chinese word for rebel. The reason? Because according to observation it has a retrograde orbit that means it rotates in the opposite direction to the sun’s rotation.
more…
CrazyNeutrino said:
Mysterious planet spotted in the outer reaches of our solar system – and it’s orbiting the sun in the wrong directionA mysterious new planet has been discovered on the far side of Neptune – but a unique characteristic of its orbit has got scientists puzzled.
The new planet has been christened “Niku” – the Chinese word for rebel. The reason? Because according to observation it has a retrograde orbit that means it rotates in the opposite direction to the sun’s rotation.
more…
(above link only gives me a page of ads and article headline). Try wikipedia: https://en.wikipedia.org/wiki/2011_KT19
New Scientist
http://arxiv.org/pdf/1608.01808v1.pdf
2011 KT19 (nicknamed Niku) is a trans-Neptunian object (TNO) that has an unusual 110 degree tilted solar orbital plane and retrograde orbit around the Sun.
It was discovered in August 2016 by a team of astronomers using the Pan-STARRS telescope, and was soon linked with a supposed prograde Centaur that had been lost, designated 2011 KT19. Notably, it is part of a group of objects which orbit the Sun in a highly inclined orbit. The clustering has significance 3.8 sigma, notable but not startling.
The orbital characteristics of 2011 KT19 have been compared to those of 2008 KV42 (Drac). The orbits of 2011 KT19, 2008 KV42, and four other objects appear to occupy a common plane, with three in prograde and three in retrograde orbits.
This one is 160,000 times fainter than Neptune, which means the icy world could be less than 200 kilometres in diameter. Detected by the Pan-STARRS 1 Outer Solar System Survey.
The current distance of Niku is 25.9 AU, well inside the orbit of Neptune at 30.8 AU.
Could it be an escaped moon from Neptune
Cymek said:
Could it be an escaped moon from Neptune
Mollwollfumble’s wiki link leads to an Arxiv article which has more information
http://arxiv.org/pdf/1608.01808v1.pdf
> is a trans-Neptunian object (TNO)
It I want to be pedantic, the above statement in wikipedia is wrong.
Minor planets in the out beyond Jupiter are classified as either Centaurs, TNOs or Scattered Disk Objects (SDOs).
Centaurs live closer than Neptune and have steep orbital inclinations
TNOs live further than Neptune and exist nearly in the plane of the solar system
SDOs live further than Neptune and have steep orbital inclinations
This new one is a Centaur, both its distance from the Sun and its orbital inclination rule it out being a TNO.
Which makes me wonder, what’s the biggest Centaur yet discovered?
What makes it mysterious?
Newly discovered, novel, quaint maybe but surely not a mystery. It seems astronomers know what it is.
gaghalfrunt said:
What makes it mysterious?
Newly discovered, novel, quaint maybe but surely not a mystery. It seems astronomers know what it is.
I suppose what’s really mysterious is why New Scientist should choose the title “Mystery object in weird orbit beyond Neptune cannot be explained” …
… when it’s closer than Neptune.
mollwollfumble said:
gaghalfrunt said:
What makes it mysterious?
Newly discovered, novel, quaint maybe but surely not a mystery. It seems astronomers know what it is.
I suppose what’s really mysterious is why New Scientist should choose the title “Mystery object in weird orbit beyond Neptune cannot be explained” …
… when it’s closer than Neptune.
Nice catch!
This isn’t even the first KBO with a retrograde orbit.
Basically the headline should have been:
“Another small, humdrum KBO has retrograde orbit”
“
dv said:
mollwollfumble said:
gaghalfrunt said:
What makes it mysterious?
Newly discovered, novel, quaint maybe but surely not a mystery. It seems astronomers know what it is.
I suppose what’s really mysterious is why New Scientist should choose the title “Mystery object in weird orbit beyond Neptune cannot be explained” …
… when it’s closer than Neptune.
Nice catch!
This isn’t even the first KBO with a retrograde orbit.
Basically the headline should have been:
“Another small, humdrum KBO has retrograde orbit”
“
scientists – sucking the fun out of headlines since 1608
> Which makes me wonder, what’s the biggest Centaur yet discovered?
I’ll look it up.
Brightest 1995 SN55
Almost as bright is the better known Chiron.
Chiron’s estimated diameter is 206 km.
So the new one’s estimated diameter of roughly 200 km is actually quite big.
That’s funny, two others, Chariklo and Pholus are supposed to be bigger.
Chariklo has an estimated diameter of, according to one source 302+-30 km and another source 248+-18 km.
> Which makes me wonder, what’s the biggest Centaur yet discovered?
I’ll look it up.
Brightest 1995 SN55
Almost as bright is the better known Chiron.
Chiron’s estimated diameter is 206 km.
So the new one’s estimated diameter of roughly 200 km is actually quite big.
That’s funny, two others, Chariklo and Pholus are supposed to be bigger.
Chariklo has an estimated diameter of, according to one source 302+-30 km and another source 248+-18 km.
One thing I hadn’t realised is the Chariklo has orbiting rings like Jupiter, Uranus and Neptune. I didn’t know that any minor planets had orbiting rings. Chiron also may have.
Let’s just check again on 2011 KT19, the new one. Marginally fainter than Pholus. Much fainter than Chariklo which in turn is much fainter than Chiron. actually orbit is further away than I thought. Semi major axis 35.6 au, compare Pluto at 39.5 au.