Jupiter imaged by Voyager 1

Jupiter’s Whirlwinds

Jupiter is famous for its long-lived whirlwind, the hurricane-like Great Red Spot (which, as we noted in a previous Science Today story, seems to be losing its greatness over time), but its turbulent atmosphere has long presented many other puzzles for planetary scientists.

For example, Jupiter’s whirlwinds spin opposite the direction of hurricanes on Earth—and it’s not even clear how they form! Scientists at the University of Alberta and the Max Planck Institute for Solar Research tried to shed light on both problems by creating computer simulations of the atmospheric phenomena. Their results suggest that the whirlwinds form from upward gas flows that originate deep within Jupiter’s atmosphere—in contrast to what happens here on Earth, with our much thinner atmosphere. As the flows ascend toward the top of the atmosphere, they get deflected in more stable regions and then swirled by the Coriolis effect.

“One of the big questions we have is how deep these structures go,” according to Moritz Heimpel at the University of Alberta. “These storms are embedded in these jet streams, and there’s no solid surface to stop them. Our simulations imply that the jet streams plunge deep into the interior, while the storms are rather shallow.”

You can watch their rainbow-colored visualizations on YouTube, or check out an image comparing the results of their model to an image of Jupiter taken by the Hubble Space Telescope.

The researchers published their findings in Nature Geoscience. But despite their successes in describing the giant planet’s atmospheric phenomena, they still couldn’t recreate the Great Red Spot. They’ll likely be demanding more supercomputer time to accomplish that! –Ryan Wyatt

Far Flung Exoplanet

A large exoplanet located far from its star may have been expelled from where it initially formed according to new UC Berkeley research. The findings were published in The Astrophysical Journal, and the team held a Google Hangout discussion this week as part of the American Astronomical Society (AAS) online conference.

Located 300 light years from Earth in the constellation Crux, the star system HD 106906 is young, only about 13 million years old. Its orbiting exoplanet, HD 106906 b, was discovered in 2013 from observations by the Magellan Telescopes in Chile, making it one of very few exoplanets ever to be directly imaged. The planet was also initially intriguing for its large size (11 times the mass Jupiter) and for its orbital distance, about 60 billion miles from its parent star (16 times further away than Pluto is from the Sun), which is far beyond where planets are thought to form.

Follow up observations—using the Gemini Planet Imager (GPI) in Chile as well as the Hubble Space Telescope—showed a highly disturbed and asymmetric debris disk around the star, with the side containing the planet very thin and extending far from the star (reaching almost to the distant exoplanet) while the other side is thicker and closer to the star. Combined with the planet’s odd 21 degree tilt off the plane of the system, the UC Berkeley team believe that HD 106906 b formed normally, much closer to its star, but was later ejected by a sudden gravitational event, pulling comets and other material along with it.

Lead author Paul Kalas points out that examining young systems like HD 106906 may provide insight into the turbulent history of our own solar system at a much younger age: “Is this a picture of our solar system when it was 13 million years old? We know that our own belt of comets, the Kuiper belt, lost a large fraction of its mass as it evolved, but we don’t have a time machine to go back and see how it was decimated. One of the ways, though, is to study these violent episodes of gravitational disturbance around other young stars that kick out many objects, including planets.” –Elise Ricard

Stellar Rorschach Test

Never heard of the star CW Leonis (a.k.a. IRC +10216)? Then you must not be an infrared astronomer. If our eyes could see in infrared light, CW Leo would be the second-brightest star in the sky!

And that means that infrared astronomers have studied CW Leo rather intently. Perhaps too intently? Because fuzzy images of the star have become something like a Rorschach test for astronomers to concoct creative descriptions of what they’re seeing. The extremely bright star (more than 10,000 times brighter than the Sun) is embedded in a dense, dusty envelope, which changes its appearance over time: take a look at this animated GIF that shows how CW Leo looked over the period from 2000–2008. Many astronomers have imagined arcs, plumes, spirals, and disks described by the data, and they couldn’t even agree on exactly where the star lies within the complex system.

“However the real excitement here is the extreme physics,” says University of Sydney graduate student Paul Stewart, who led the research team studying CW Leo. “It is a swollen luminous giant poised at the most self-destructive phase of its existence. It is literally tearing itself apart under its own glare, hurling dense clouds of dust and gas out into the galaxy; dying amidst its own glorious final fireworks display.”

“It is pretty clear that the new images tell us is that CW Leo has just been ejecting clumps and plumes of hot dust at random all this time,” according to Peter Tuthill, co-author on the publication. “It is like a celestial version of the famous Rorschach Ink Blot Test in psychology. In trying to find underlying structure to the clumps and blobs, we have seen little more than our own preconceptions reflected back at us. Seeing rabbits or elephants in the clouds is okay for my four-year old boy, but it seems that this time a dusty star in Leo has caught all the astronomers out daydreaming at their work.”

Or in the words of the Royal Astronomical Society press release, “Curious ‘Inkblot’ star outed for trolling the astronomers.” –Ryan Wyatt

Image: Jupiter by Voyager 1, NASA, Caltech/JPL

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