Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print Computer models suggest planetary and extrasolar planet atmospheres

Computer models suggest planetary and extrasolar planet atmospheres

June 20, 2007

The world is abuzz with the discovery of an extrasolar, Earth-like planet around the star Gliese 581 that is relatively close to our Earth at 20 light years away in the constellation Libra.

Bruce Fegley, Jr., Ph.D., professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, has worked on computer models that can provide hints to what comprises the atmosphere of such planets and better-known celestial bodies in our own solar system.




New computer models, from both Earth-based spectroscopy and space mission data, are providing space scientists compelling evidence for a better understanding of planetary atmospheric chemistry. Recent findings suggest a trend of increasing water content in going from Jupiter (depleted in water), to Saturn (less enriched in water than other volatiles), to Uranus and Neptune, which have large water enrichments.

"The farther out you go in the solar system, the more water you find," said Fegley.

Fegley provided an overview of comparative planetary atmospheric chemistry at the 233rd American Chemical Society National Meeting, held March 25-29, 2007, in Chicago. Fegley and Katharina Lodders-Fegley, Ph.D., research associate professor of earth and planetary sciences, direct the university's Planetary Chemistry Laboratory.

"The theory about the Gas Giant planets (Jupiter, Saturn, Uranus, and Neptune) is that they have primary atmospheres, which means that their atmospheres were captured directly from the solar nebula during accretion of the planets," Fegley said.

Gas Giants

He said that Jupiter has more hydrogen and helium and less carbon, nitrogen and oxygen than the other Gas Giant planets, making its composition closer to that of the hydrogen- and helium-rich sun. The elements hydrogen, carbon and oxygen are predominantly found as water, the gases molecular hydrogen and methane and in the atmospheres of the Gas Giant planets.

"Spectroscopic observations and interior models show that Saturn, Uranus and Neptune are enriched in heavier elements," he said. "Jupiter, based on observations from the Galileo Probe, is depleted in water. People have thought that Galileo might just have gone into a dry area. But Earth-based observations show that the carbon monoxide abundance in Jupiter's atmosphere is consistent with the observed abundances of methane, hydrogen and water vapor. This pretty much validates the Galileo Probe finding."

The abundances of these four gases are related by the reaction CH4+H20 = CO+3H2. Thus, observations of the methane, hydrogen and CO abundances can be used to calculate the water vapor abundance. Likewise, Earth-based observations of methane, hydrogen and carbon monoxide in Saturn's atmosphere show that water is less enriched than methane.

In contrast, observations of methane, hydrogen and carbon monoxide in the atmospheres of Uranus and Neptune show that water is greatly enriched in these two planets. Although generally classed with Jupiter and Saturn, Uranus and Neptune are water planets with relatively thin gaseous envelopes.

"On the other hand, the terrestrial planets Venus, Earth and Mars have secondary atmospheres formed afterwards by outgassing - heating up the solid material that was accreted and then releasing the volatile compounds from it," Fegley said. "That then formed the earliest atmosphere."

He said that by plugging in models he's done on the outgassing of chondritic materials and using photochemical models of the effects of UV sunlight, he and his collaborator Laura Schaefer, a research assistant in the Washington University Department of Earth and Planetary Sciences, can speculate on the atmospheric composition of Earth-like planets in other solar systems.

"With new theoretical models we are able to surmise the outgassing of materials that went into forming the planets, and even make predictions about the atmospheres of extrasolar terrestrial planets," he said.

"Because the composition of the galaxy is relatively uniform, most stars are like the sun - hydrogen-rich with about the same abundances of rocky elements - we can predict what these planetary atmospheres would be like," Fegley said. "I think that the atmospheres of extrasolar Earth-like plants would be more like Mars or Venus than the Earth."

Fegley said that photosynthesis accounts for the oxygen in Earth's atmosphere; without it, the Earth's atmosphere would consist of nitrogen, carbon dioxide and water vapor, with only small amounts of oxygen. Oxygen is 21 percent of Earth's atmosphere; in contrast, Mars has about one-tenth of one percent made by UV sunlight destroying carbon dioxide.

"I see Mars today as a great natural laboratory for photochemistry; Venus is the same for thermochemistry, and Earth for biochemistry," he said. "Mars has such a thin atmosphere compared to Earth or Venus. UV light can penetrate all the way down to the Martian surface before it's absorbed. That same light on Earth is mainly absorbed in the ozone layer in the lower Earth stratosphere. Venus is so dense that light is absorbed by a cloud layer about 45 kilometers or so above the Venusian surface."

Washington University School of Medicine in St. Louis



Related Extrasolar Planet Current Events and Extrasolar Planet News Articles Extrasolar Planet Current Events and Extrasolar Planet News RSS Extrasolar Planet Current Events and Extrasolar Planet News RSS
Caltech scientists predict greater longevity for planets with life
Roughly a billion years from now, the ever-increasing radiation from the sun will have heated Earth into inhabitability; the carbon dioxide in the atmosphere that serves as food for plant life will disappear, pulled out by the weathering of rocks; the oceans will evaporate; and all living things will disappear.

NASA/University team develops new method to find alien oceans
NASA-sponsored scientists looking back at Earth with the Deep Impact/EPOXI mission have developed a method to indicate whether Earth-like alien (extrasolar) worlds have oceans.

New technique could find water on Earth-like planets orbiting distant suns
Since the early 1990s astronomers have discovered more than 300 planets orbiting stars other than our sun, nearly all of them gas giants like Jupiter.

Missing planets attest to destructive power of stars' tides
During the last two decades, astronomers have found hundreds of planets orbiting stars outside our solar system. New research indicates they might have found even more except for one thing - some planets have fallen into their stars and simply no longer exist.

Finding Twin Earths: Harder Than We Thought!
Does a twin Earth exist somewhere in our galaxy? Astronomers are getting closer and closer to finding an Earth-sized planet in an Earth-like orbit. NASA's Kepler spacecraft just launched to find such worlds.

European team finds smallest transiting extrasolar planet ever
The CoRoT satellite has discovered a planet only twice as large as the Earth orbiting a star slightly smaller than the Sun. It is the smallest extrasolar planet (planet outside our solar system) whose radius has ever been measured.

Hubble finds carbon dioxide on an extrasolar planet
The NASA/ESA Hubble Space Telescope has discovered carbon dioxide in the atmosphere of a planet orbiting another star.

Hubble finds first organic molecule on extrasolar planet
The tell-tale signature of the molecule methane in the atmosphere of the Jupiter-sized extrasolar planet HD 189733b has been found with the Hubble Space Telescope. Under the right circumstances methane can play a key role in prebiotic chemistry - the chemical reactions considered necessary to form life as we know it.

Deep Impact extended mission heads for comet Hartley 2
NASA has given a University of Maryland-led team of scientists the green light to fly the Deep Impact spacecraft to Comet Hartley 2 on a two-part extended mission known as EPOXI. The spacecraft will fly by Earth on New Year's Eve at the beginning of a more than two-and-a-half-year journey to Hartley 2.

Hazy red sunset on extrasolar planet
A team of astronomers have used the NASA/ESA Hubble Space Telescope to detect, for the first time, strong evidence of hazes in the atmosphere of a planet orbiting a distant star. The discovery comes after extensive observations made recently with Hubble's Advanced Camera for Surveys (ACS).
More Extrasolar Planet Current Events and Extrasolar Planet News Articles
Extrasolar Planets and Astrobiology

Extrasolar Planets and Astrobiology
by Caleb A. Scharf (Author)

This book offers an advanced introduction to the increasingly robust fields of extrasolar planets and astrobiology. No other text currently available applies this level of mathematics and physics, while also providing an extensive grounding in key issues of chemistry, biology, and geophysics. With extensive references to the literature and chapter-ending exercises, this book can be used as the core text for teaching undergraduate or introductory graduate level courses. The text will also provide astrobiologists with an indispensable "User's Manual" when quick reference to key mathematical and physical techniques is needed. A continually updated online component, fully cross referenced with the text, is also available. Foreword by Geoff Marcy.

The New Worlds: Extrasolar Planets (Springer Praxis Books / Popular Astronomy)

The New Worlds: Extrasolar Planets (Springer Praxis Books / Popular Astronomy)
by Fabienne Casoli (Author), Thérèse Encrenaz (Author)

The detection and exploration of extrasolar planets is one of the most exciting and fast moving areas of astronomical research at the present time. With over forty research programmes ongoing, and just as many planned, the search for these new worlds has become the main objective for a new generation of giant ground-based telescopes as well as many future space missions. Experimental methods and observational techniques are pushing existing instruments to their limits. The most exciting possibility offered by this research is the discovery of Earth-like extrasolar planets, with a mass comparable to that of Earth, located at the right distance from its star to host liquid water - in other words, a place where life could evolve.

The authors tackle this challenging...

The Crowded Universe: The Search for Living Planets

The Crowded Universe: The Search for Living Planets
by Alan Boss (Author)

We are nearing a turning point in our quest for life in the universe—we now have the capacity to detect Earth-like planets around other stars. But will we find any?

In The Crowded Universe, renowned astronomer Alan Boss argues that based on what we already know about planetary systems, in the coming years we will find abundant Earths, including many that are indisputably alive. Life is not only possible elsewhere in the universe, Boss argues—it is common.

Boss describes how our ideas about planetary formation have changed radically in the past decade and brings readers up to date on discoveries of bizarre inhabitants of various solar systems, including our own. America must stay in this new space race, Boss contends, or risk being left out of one of the most profoundly important...

  Shows a Dramatic Close-Up of the Extrasolar Planet XO-1B Passing in Front of a Sun-Like Star Art Photographic Poster Print by Stocktrek Images, 48x36
by AllPosters.com

AllPosters.com is the world's #1 seller of posters, prints, photographs, specialty products and framed art. We're dedicated to bringing our customers the best selection of high quality wall décor that is perfect for their home or office. Browse our catalog of over 300,000 items that include entertainment and specialty posters, decorative prints, and art reproductions. Whether you're looking for your favorite movie or music poster, a framed Monet reproduction, or a print of the Eiffel Tower you will find it at AllPosters.com. Visit our Amazon store today at www.amazon.com/allposters to find Special Offers and search by subject category or artist. AllPosters.com provides unmatched service with a 100% satisfaction guarantee. We ship internationally to over 80 countries. Decorate your...

A Decade of Extrasolar Planets around Normal Stars (Space Telescope Science Institute Symposium Series)

A Decade of Extrasolar Planets around Normal Stars (Space Telescope Science Institute Symposium Series)
by Mario Livio (Editor), Kailash Sahu (Editor), Jeff Valenti (Editor)

Humans have long thought that planetary systems similar to our own should exist around stars other than the Sun, yet the search for planets outside our Solar System has had a dismal history of discoveries that could not be confirmed. However, this all changed in 1995, with the past decade witnessing astonishing progress in this field; we now know of more than 200 extrasolar planets. These findings mark crucial milestones in the search for extraterrestrial life - arguably one of the most intriguing endeavors of modern science. These proceedings from the Space Telescope Science Institute Symposium on Extrasolar Planets explore one of the hottest topics in astronomy today. Discussions include the Kepler mission, observational constraints on dust disk lifetimes and the implications for planet...

Extrasolar Planets

Extrasolar Planets
by Ron Miller (Author)



Extrasolar Planets

Extrasolar Planets
Pool of Frogs (Primary Contributor)



Planetary Systems: Detection, Formation and Habitability of Extrasolar Planets (Astronomy and Astrophysics Library)

Planetary Systems: Detection, Formation and Habitability of Extrasolar Planets (Astronomy and Astrophysics Library)
by M. Ollivier (Author), T. Encrenaz (Author), F. Roques (Author), F. Selsis (Author), F. Casoli (Author)

Over the past ten years, the discovery of extrasolar planets has opened a new field of astronomy, and this area of research is rapidly growing, from both the observational and theoretical point of view. The presence of many giant exoplanets in the close vicinity of their star shows that these newly discovered planetary systems are very different from the solar system. New theoretical models are being developed in order to understand their formation scenarios, and new observational methods are being implemented to increase the sensitivity of exoplanet detections.

In the present book, the authors address the question of planetary systems from all aspects. Starting from the facts (the detection of more than 300 extraterrestrial planets), they first describe the various methods...

Artist's Impression of a Jupiter-Size Extrasolar Planet Being Eclipsed by its Parent Star Photographic Poster Print by Stocktrek Images, 24x18

Artist's Impression of a Jupiter-Size Extrasolar Planet Being Eclipsed by its Parent Star Photographic Poster Print by Stocktrek Images, 24x18
by Art.com

Art.com is the world's largest retailer of art prints, posters, photographs, and framed artwork. With our huge selection of over 400,000 prints, you'll easily find the perfect piece for your home, office, or classroom. Our art is printed on quality paper. When you order framed artwork, the piece is built by our team of in-house professionals. Visit our Amazon store today at www.amazon.com/artdotcom to find Special Offers and search for products based on 'Artist Name' and 'Subject Categories' such as Movie, Music, Vintage, TV, Children, Travel, Kitchen, Museum Art, Animals, Floral, Motivational, and Sports. Art.com is dedicated to providing you with high quality products and service by offering you 100% satisfaction guaranteed. We ship internationally to over 80 countries. Decorate your...

Extrasolar Planets: Formation, Detection and Dynamics

Extrasolar Planets: Formation, Detection and Dynamics
by Rudolf Dvorak (Editor)

This latest, up-to-date resource for research on extrasolar planets covers formation, dynamics, atmospheres and detection. After a look at the formation of giant planets, the book goes on to discuss the formation and dynamics of planets in resonances, planets in double stars, atmospheres and habitable zones, detection via spectra and transits, and the history and prospects of ESPs as well as satellite projects.

Edited by a renowned expert in solar system dynamics with chapters written by the leading experts in the method described—from the US and Europe—this is an ideal textbook for graduates, students in astronomy, and astronomers.

© 2009 BrightSurf.com