Posted on 04/29/2005 10:22:03 PM PDT by neverdem
A reddish speck photographed near a dim and distant star last year is indeed a planet, about five times the mass of Jupiter, an international team of astronomers is reporting today.
They say the results bolster their claim, put forward last fall, that this image was the first of a planet orbiting a star outside the solar system.
The planet, about 230 light-years from Earth in the constellation Hydra, orbits a kind of failed star known as a brown dwarf at a distance of at least five billion miles, twice as far as icy Neptune is from our own Sun. Spectroscopic measurements show water vapor in its atmosphere, suggesting that it is cold like a planet and not hot like a star.
"This discovery offers new perspectives for our understanding of chemical and physical properties of planetary mass objects as well as their mechanisms of formation," Dr. Gael Chauvin of the European Southern Observatory in Chile and his colleagues wrote in the paper, in the journal Astronomy and Astrophysics.
When Dr. Chauvin's group first announced the discovery of the object, known officially as 2M1207b, last year, they admitted that they could not prove that it was not just a background object unrelated to the brown dwarf. Subsequent observations using the Very Large Telescope on Cerro Paranal in northern Chile and a system designed to take the twinkle out of starlight and thus get sharper images showed that the dwarf star and the suspected planet were moving together across the sky, cementing the notion that they are gravitationally bound.
Measurements of the same system with the Hubble Space Telescope are to be reported on Monday in Baltimore at a meeting on extrasolar planets.
In the last decade, astronomers have detected, by indirect means, some 150 planets around other stars, setting off a race to see these objects in their own light. Such observations will allow them to study the composition and other properties of these "exoplanets" and compare them to the denizens of the solar system and to one other.
In the year it has taken the European group to cement its claim, other groups have claimed to have seen the first light from extrasolar planets. Last month, for example, a group led by Dr. Ralph Neuhäuser of Jena University in Germany, using the same telescope and camera, reported that they had imaged a planet of two Jupiter masses circling the star GQ Lup. But some astronomers have questioned the reliability of their estimate of its mass, arguing that it could be heavy enough to be a brown dwarf.
In a second paper, to appear in the same journal, Dr. Chauvin's team is reporting another discovery, of a companion to the star AB Pictoris, a young star about 150 light years from Earth. That object, known as AB Pic b, is about 13 or 14 times the mass of Jupiter, they estimate, putting it right on the line between planets and brown dwarfs.
Like the earlier planet and GQ Lup, AB Pic b is orbiting at an enormous distance from its star, 23 billion miles, and that is a new puzzle for the planet hunters, Dr. Ben Zuckerman of the University of California, Los Angeles, a member of the team, said. Dr. Zuckerman noted that these were very far out compared with any previously known planets, which raised questions about how and where they had formed.
"It's a new kind of system," Dr. Zuckerman said, adding that they are also rare. "They are relatively few and far between."
Thanks! I wasn't too sure of that -- some Arthur C Clarke books are masterpieces -- like Rendezvous with Rama, but some others are real duds. I'm a big Asimov fan -- you>?
Thanks for the ping. I may not alert the list over this. We've had quite a few threads on extra-solar planets lately.
"The planet is about 1,350 trillion miles away from us."
Beam us up Scotty.
C'mon, if you want to know about real science, you shouldn't be reading science fiction stories. In fact, you shouldn't read articles about science topics in the MSM, or scientific magazines aimed at the general public (Discover, Omni, etc.). Stay away from scientific documentaries, as well. As sources of scientific information, they all suck. If you're just looking for entertainment, they're probably okay.
" How the heck can this planet be five times the mass of Jupiter and not start fusing it's lighter elements under it's own extreme gravitational pressure? "
The smallest true star known (with active fusion) has 100 times the mass of Jupiter.
Arthur Clarke's premise in turning Jupiter into a star was to artificially compress the matter to achieve a fusion process. It is not based on the natural mass and gravitational pressure in Jupiter, but a science fiction construct of an advanced civilization.
“Spectroscopic measurements show water vapor in its atmosphere, suggesting that it is cold like a planet and not hot like a star.”
“…..under it's own extreme gravitational pressure?”
With such a strong gravity, how could there be “water vapor in it’s” atmosphere”????
I recently picked up a copy of Clarke's "Fountains of Paradise" just to read his description of a space elevator. What's funny and encouraging about the recent news on the development of a real space elevator is that Clarke has us in the mid 21st Century and already back on the Moon and established on Mars before a substance strong enough and light enough to support a space elevator is discovered.
Alright. How is gravitational pull exerted? How does that kind of attraction have an influence on another body billions of miles away?
Check Gravity after clicking on Mechanics at Hyperphysics.
Great resource, thanks!
Basically, I learned that it takes two bodies acting on each other for either object to react. That while acting upon one another, the bodies exchange massless particles, and the the force of gravity is acting along a line between the centers of the two masses.
I bookmarked it a while ago. As a refresher, I thought it was the best thing since sliced bread.
I was going to say about 80 Jovian masses, but we're both in the same ball park. Basically, to be a naturally formed star whose energy is being supplied by ongoing fusion reactions, you need a minimum of about 0.1 solar masses. Brown dwarfs are what I like to call "stellar wannabes" who got "voted off the island" because they don't quite have the mass it takes to get the job done of initiating AND maintaining an ongoing fusion reaction.
ROTF!
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