Featured Research

from universities, journals, and other organizations

Space Scientist Proposes New Model For Jupiter's Core

Date:
December 30, 2004
Source:
Washington University In St. Louis
Summary:
After eleven months of politics, now it's time for some real "core values" - not those of the candidates but those of the great gas giant planet, Jupiter. Katharina Lodders, Ph.D., Washington University in St. Louis research associate professor in Earth and Planetary Sciences in Arts & Sciences, studying data from the Galileo probe of Jupiter, proposes a new mechanism by which the planet formed 4.5 billion years ago.

The planet Jupiter may have a core of tar, according to new reasearch from WUSTL.
Credit: Photo courtesy of Washington University In St. Louis

Dec. 9, 2004 — After eleven months of politics, now it's time for some real "core values" - not those of the candidates but those of the great gas giant planet, Jupiter.

Katharina Lodders, Ph.D., Washington University in St. Louis research associate professor in Earth and Planetary Sciences in Arts & Sciences, studying data from the Galileo probe of Jupiter, proposes a new mechanism by which the planet formed 4.5 billion years ago.

The widely accepted model for Jupiter's formation assumes that its overall composition is similar to that of the Sun, with enrichments of oxygen and other elements heavier than helium. Jupiter's core was believed to be a massive snowball that formed in the cold reaches of the outer solar nebula, the gas and dust cloud from which the solar system formed. However, the Galileo probe mass spectrometer found much less water than expected in Jupiter's atmosphere.

Taking the mass spectrometer data and earlier Earth-based infrared spectroscopic measurements at face value, Lodders calculated that Jupiter is depleted in water and thus in oxygen. The Jovian oxygen inventory is only about half of the oxygen elemental abundance in the Sun. On the other hand, the Galileo probe mass spectrometer data show that Jupiter's carbon inventory is about 1.7 times larger than that in the Sun. Based on these data, Lodders argues that Jupiter's core was mainly tar instead of ice.

Snow line yields to tar line

Lodders' theoretical model assumes an outer solar system warmer than previously thought. Her theory replaces what astronomers call the "snow line," the point in the solar nebula where water ice condenses, with the new "tar line," the point where asphalt or tar-like material formed, pushing the snow line farther out in the solar nebula.

Picture a snowy street in winter and a fresh layer of tar on part of that street.

"Snow will evaporate with warmer temperatures but the tar will stay" said Lodders. "Also consider the fact that organics make a kind of sticky goo, which is good for gathering rocks and building the core. Imagine an ice cube and sticking bits of rock to it, then think of maple syrup. What's going to have better sticking properties?"

Jupiter's core formed rapidly relative to the rate at which gas was lost from the solar nebula. Once its core reached about 10 Earth masses, gravitational attraction captured the surrounding nebular gas and built up the gas giant planet we observe today. The core question, if you will, is: If there was a lot of water ice that helped to built the Jovian core, where is the water now?

"My thinking is to look at the (Galileo) data, accept them and come up with a new theory, a new model instead of fitting the observations to the older model," said Lodders. "It's always bad, though, if you reject a model and don't come up with a better one. "

Portrait of a dry planet

The observations indicate that water is depleted on Jupiter. "If there never was much water ice you never expect to observe much water in the atmosphere now," said Lodders. "However, you need to build a large proto-core fast, because otherwise you don't have enough mass there to accrete gas and to make a gas giant planet."

But Jupiter is enriched in carbon, and Lodders notes that there is much evidence for carbon being locked up in organic material on outer solar system planets, comets, and meteorites, and the interstellar medium from which our solar system originated.

Lodders proposes that the Jovian core is originally tar and rock, steadily growing to the point where it accretes gas from the solar nebula, primarily hydrogen and helium. Energy from the accretion heats up Jupiter, reacting the tar and making methane, the third most abundant gas observed in the planet's atmosphere after hydrogen and helium.

"Up to fifty percent of the carbon in the interstellar medium may be in organic solids," she pointed out. "Organic solids are abundant out there and Jupiter is enriched in carbon, so it makes sense to assume that organic solids - instead of water ice - provided the glue to rapidly build the proto Jovian core."

Lodders described her new model at the annual meeting of the Division of Planetary Sciences of the American Astronomical Society in Louisville, Kentucky, from Nov. 8-12, 2004, and in the Aug. 10, 2004 issue of the Astrophysical Journal.


Story Source:

The above story is based on materials provided by Washington University In St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University In St. Louis. "Space Scientist Proposes New Model For Jupiter's Core." ScienceDaily. ScienceDaily, 30 December 2004. <www.sciencedaily.com/releases/2004/12/041220011521.htm>.
Washington University In St. Louis. (2004, December 30). Space Scientist Proposes New Model For Jupiter's Core. ScienceDaily. Retrieved September 15, 2014 from www.sciencedaily.com/releases/2004/12/041220011521.htm
Washington University In St. Louis. "Space Scientist Proposes New Model For Jupiter's Core." ScienceDaily. www.sciencedaily.com/releases/2004/12/041220011521.htm (accessed September 15, 2014).

Share This



More Space & Time News

Monday, September 15, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

SpaceX's Elon Musk Really Wants To Colonize Mars

SpaceX's Elon Musk Really Wants To Colonize Mars

Newsy (Sep. 14, 2014) Elon Musk has been talking about his goal of colonizing Mars for years now, but how much of it does he actually have figured out, and is it possible? Video provided by Newsy
Powered by NewsLook.com
International Space Station Crew Returns Safely To Earth

International Space Station Crew Returns Safely To Earth

Newsy (Sep. 11, 2014) The three-man crew touched down in Kazakhstan Wednesday after more than five months of science experiments in orbit. Video provided by Newsy
Powered by NewsLook.com
Solar Storm To Hit This Weekend, Scientists Not Worried

Solar Storm To Hit This Weekend, Scientists Not Worried

Newsy (Sep. 11, 2014) Two solar flares which erupted in our direction this week will arrive this weekend. The resulting solar storm will be powerful but not dangerous. Video provided by Newsy
Powered by NewsLook.com
Solar Flare Surges Off Sun

Solar Flare Surges Off Sun

Reuters - US Online Video (Sep. 11, 2014) NASA captures video of a significant flare surging off the sun. Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins