Current Weather
The Spy FM

Peek Into Exoplanet’s Atmosphere Offers Clues To How It Was Formed

Filed by KOSU News in Science.
March 15, 2013

Scientists peering into the atmosphere of a giant planet 130 light years away believe their findings bolster one theory of how solar systems form.

The planet, orbiting the star HR 8799, is part of a solar system containing at least three other “super-Jupiters” weighing in at between five and 10 times the mass of our own Jupiter. The nearby system features a brash, young 30-million-year-old star (by contrast, our Sun is in mid-life at about 4.5 billion years old).

The fact that the planets are “large, young, and very far from their parent star,” made them an easy mark for researchers, Christian Marois of the National Research Council of Canada, one of the study’s co-authors, was quoted as saying by The Space Reporter.

Space.com quotes another co-author, Bruce Macintosh, an astronomer at Lawrence Livermore National Laboratory in California as saying that HR 8799 is “the only system in which multiple planets can individually be seen.”

The team, which used the Keck II 10-meter telescope on Hawaii’s Mauna Kea volcano to capture infrared light from the planet, wanted to know if the composition of its atmosphere could lend credence to one of two leading models of solar system formation – the venerable “core accretion” theory or the newer one, called “gravitational instability.”

Here’s a quick primer:

Core accretion – A flattened disk of material forms around a new star and gradually the particles form small orbiting clumps that get progressively bigger until they are planet-sized.

Gravitational Instability – Planets form in “havens of stability” whipping around a star amid an otherwise turbulent disk of gas.

What the scientists found in the atmosphere of HR 8799c — one of the super-Jupiters that orbits about as far from its host star as our Pluto does from the Sun — was water vapor and carbon dioxide. But no methane.

The lack of methane “tells us that there must be mixing between the different layers of the atmosphere, much like a lava lamp swirls material up and down,” co-author Quinn Konopacky, an astronomer at the University of Toronto, tells Space.com.

“Since methane is a sensitive molecule, it can be destroyed when it gets mixed into the deeper, hotter parts of the atmosphere. This mixing tells us about the atmospheric conditions in young Jupiter-like planets.”

Although they saw a lot of water vapor, it was less than they’d expected, meaning a little more carbon than oxygen, Konopacky explains.

And that suggests core accretion was the planet-building mechanism in the star system, she says.

There’s one small problem: The classic core accretion theory can’t account for such large planets as HR 8799c forming so far from their host stars. According to Space.com:

Researchers are now tinkering with existing models of core accretion to see how planets might form via the process at great distances from their stars. For instance, there may be more matter at the outer edges of the protoplanetary discs of matter around stars that give rise to planets than before thought, or perhaps solid matter could stick together and form planetary cores easier or faster than previously suspected.

[Copyright 2013 NPR]

Leave a Reply

6AM to 7AM On Being

On Being

On Being engages listeners across the spectrum of belief and non-belief in conversation about life's deepest questions. From autism to the ethics of torture, Krista and her guests reach beyond the headlines to probe faith and meaning, ethics and new ways of being, amidst the political, ecological, economic, cultural and technological shifts that define 21st century life.

Listen Live Now!

8AM to 10AM Weekend Edition

Weekend Edition

Weekend Edition Sunday premiered on January 18, 1987, and was the last of NPR's major newsmagazines to hit air. Since then, Weekend Edition Sunday has covered newsmakers and artists, scientists and politicans, music makers of all kinds, writers, thinkers, theologians and all manner of news events.

View the program guide!

9AM to 10PM Sound Opinions

Sound Opinions

Take two nationally respected rock critics, the latest music news, personal commentary, and exclusive interviews and performances, add a huge pile of records old and new, and the result is Sound Opinions-the world's only rock and roll talk show.

View the program guide!

Upcoming Events in your area (Submit your event today!)

Streaming audio and podcasts

Stream KOSU on your smartphone

Phone Streaming

SmartPhone listening options on this page are intended for many iPhones, Blackberries, etc. with low-cost software applications available to listen to our full-time web streams, both News on KOSU-1 and Classical on KOSU-2.

Learn more about our complete range of streaming services

We're perfecting the patient experience - Stillwater Medical Center