Weird Planet Is Orbiting Backwards Between Two Stars (newscientist.com) 15
Astronomers have confirmed the existence of a bizarre planet in the Nu Octantis binary star system that orbits in reverse between two stars -- one of which is now a white dwarf. This retrograde orbit, once thought impossible, defies traditional planetary formation models and may have resulted from dramatic shifts in the system's history. New Scientist reports:
The key observation was that the Nu Octantis planet is retrograde -- the planet and one star both orbit the second star, but they do so in opposite directions, with the planet having the tighter orbit around the second star. [Man Hoi Lee at the University of Hong Kong] says this is unusual but makes the system's configuration stable -- even though it means that the planet repeatedly moves through the narrow space between the two stars. His team was able to determine this with lots of certainty thanks to improved measuring devices, such as the HARPS spectrograph at the European Southern Observatory's 3.6-metre telescope in Chile. The fact that the planet's signal persisted through years of observation helped too. "We are pretty sure [the planet] is real, because if it was something like stellar activity, it shouldn't be so consistent in years of data," says Lee.
But this backwards-moving planet isn't the only exotic feature of Nu Octantis. The researchers used the European Southern Observatory's Very Large Telescope, also in Chile, to determine that one of its stars is a white dwarf, which means that it has reached the end of its life cycle, becoming denser and smaller. Lee says this complicates the Nu Octantis threesome's history because mathematical models of its past show that the planet's current orbit was impossible when this star was younger, bigger and brighter. So, the planet either used to orbit both stars at once, but then radically shifted trajectory when one of the two stars became a white dwarf, or it was formed from the mass that the star ejected as it transformed into a white dwarf. Future observations, and a lot more mathematical modelling, may be able to pinpoint which of these scenarios is more likely to have occurred, but both are rather novel, says Lee. The research has been published in the journal Nature.
But this backwards-moving planet isn't the only exotic feature of Nu Octantis. The researchers used the European Southern Observatory's Very Large Telescope, also in Chile, to determine that one of its stars is a white dwarf, which means that it has reached the end of its life cycle, becoming denser and smaller. Lee says this complicates the Nu Octantis threesome's history because mathematical models of its past show that the planet's current orbit was impossible when this star was younger, bigger and brighter. So, the planet either used to orbit both stars at once, but then radically shifted trajectory when one of the two stars became a white dwarf, or it was formed from the mass that the star ejected as it transformed into a white dwarf. Future observations, and a lot more mathematical modelling, may be able to pinpoint which of these scenarios is more likely to have occurred, but both are rather novel, says Lee. The research has been published in the journal Nature.
YT Link (Score:5, Informative)
The key observation was that the Nu Octantis planet is retrograde -- the planet and one star both orbit the second star, but they do so in opposite directions, with the planet having the tighter orbit around the second star.
This (old) vid should help if you're having trouble visualizing the orbits:
https://www.youtube.com/watch?... [youtube.com]
Re: (Score:1)
Re: YT Link (Score:2)
Yes, especially if you say it orbits backward without completing the motion description.
Larry Niven's universe (Score:2)
There is short story from Larry Niven that seems to be this situation. "The Soft Weapon".
Nomenclature out the window... (Score:3)
This system however throws that out of the window. Sure, the stars are a binary system, but to the planet, the White dwarf orbits like a planet. So whilst it is a binary star system, from the planet's perspective, it's not. The white dwarf is just a big glowing planet orbiting a star.
On another note, it would be a fantastic spectacle to view the parent stars on that planet. Sometimes you'd have day and night, other times you'd have day and not-so-day.
Re: (Score:2)
I don't think we have enough info to imply how the planet itself is rotating.
Re: (Score:3)
If the planet is tidally locked to its parent star, then on the permanent-day hemisphere you'd periodically have two suns in the sky and
Stanisaw Lem's Solaris (Score:2)
In fact Solaris, from the book by Stanisaw Lem, orbits two starts. Probably the reason why it has this orbit is due to a big gelatinous sentient being that creates humans using neutrinos, who knows...
Corner case (Score:3)
This whinging about how astronomers don't know how to explain this.
Anyone developing softwares knows it is the corner cases where you earn your pay.
Re: (Score:3)
This whinging about how astronomers don't know how to explain this.
Anyone developing softwares knows it is the corner cases where you earn your pay.
The pop culture version of science and physics, always requires weird hyperbole like Scientists are stunned, or perplexed, or some other word that insinuates that they are about to jump off a tall building because their beliefs have been shattered anytime something new is discovered. You'd get the impression that the James Webb Telescope is something they never wanted built, if you look at many of the vids on Youtube.
In fact, they are excited More information, more data, more refinement of theory. What
But how (Score:2)
Re:But how (Score:4, Informative)
From the linked abstract:
Stable fits to all radial velocity data require the planetary orbit to be retrograde and practically coplanar.
One weird trick (Score:3)
This planet found the secret to keeping his mommy and daddy stars together!
Sounds Quite Roasty for the Planet (Score:3)
The key observation was that the Nu Octantis planet is retrograde – the planet and one star both orbit the second star, but they do so in opposite directions, with the planet having the tighter orbit around the second star. Lee says this is unusual but makes the system’s configuration stable – even though it means that the planet repeatedly moves through the narrow space between the two stars. [newscientist.com]
Bizarro world (Score:2)
Uh-oh. Superman's nemesis finally found.