Posted on 03/22/2005 7:09:53 PM PST by neverdem
Astronomers said yesterday that they, or at least their telescopes, had laid eyes for the first time on planets beyond the solar system.
Using the NASA Spitzer Space Telescope and careful timing, two different teams studying two different planets were able to distinguish the glow of the planets' infrared radiation from the overwhelming glare of their parent stars. Both planets are so-called hot Jupiters, massive bodies circling their stars in tight, blowtorching orbits and probably unfit for the kind of life found on Earth.
Until now, astronomers could infer the existence and some properties of these and other so-called exoplanets only by indirect means. They said directly measuring light from the planets was a major step in the quest to understand what alien planets are made of, because different molecules in the atmosphere absorb infrared light in characteristic ways and allow scientists to compare these alien planets to those in the solar system. Ultimately, astronomers would like to know if Earth, with its ability to evolve and support life, is unique or common in the universe.
Dr. David Charbonneau of the Harvard-Smithsonian Center for Astrophysics, who led one of the teams, said he was ecstatic when he first saw the data. "We've been hunting for this light for almost 10 years, ever since extrasolar planets were first discovered," Dr. Charbonneau said.
The Harvard-Smithsonian team and the other team, led by Dr. L. Drake Deming of the Goddard Space Flight Center, announced their results at a news conference at the headquarters of the National Aeronautics and Space Administration in Washington. The Deming team's paper was published online yesterday by the journal Nature; the other team will publish its results in The Astrophysical Journal on June 20.
Dr. Geoffrey W. Marcy, a planet hunter at the University of California, Berkeley, called the results "the stuff of history books" and added, "With this result, we are closer to understanding our own human roots, chemically, among the stars."
Dr. Alan P. Boss, a planetary theorist at the Carnegie Institution of Washington, said in an e-mail message that the discoveries showed "that we are well along the way to combining astronomy and biology into the new science of astrobiology, with the ultimate goal being to search for life beyond Earth."
About 130 planets are known to orbit other stars, but until now they have all been detected indirectly, either by the wobble their gravity induced in the motions of their parent stars or by slight dips in the stars' light when their planets passed in front of them.
The planets whose discoveries were reported yesterday fall in the latter category, passing directly in front of their parent stars periodically and then behind them. The Goddard team's object, known as HD 209458b, was the first planet detected by the so-called transit method, back in 1999. It circles a star about 153 light-years away in the constellation Pegasus, making a complete trip every 3.5 days. In 2001, Dr. Charbonneau used the Hubble Space Telescope to make spectroscopic measurements of this star while the planet was passing in front of it and found that sodium and hydrogen were present in the planet's atmosphere.
The other planet, known as TrES-1 after the telescope network that discovered it, the Trans-Atlantic Exoplanet Survey, is about 500 light-years away in the constellation Lyra. Discovered last year by a telescope only four inches in diameter, it circles its parent every three days.
In both cases the astronomers were able to use the special geometry of these planetary systems to tease out the faint light of each planet from its parent's glare, comparing measurements made while the planet and star were both visible and while the planet was hidden behind the star. It helped that the Spitzer telescope, launched in 2003, was built to study infrared radiation, which has a longer wavelength than visible light. Because they are so close to their stars, these planets were expected to be hot and therefore show up more easily at infrared wavelengths than in the visible light. While the stars outshine such giant planets by a factor of 10,000 or so in visible light, they are only about 400 times brighter in infrared.
When the astronomers put on their "infrared goggles," as Dr. Charbonneau put it, the planets popped into view. The Spitzer telescope registered a dip in light of about a quarter of 1 percent in each case when the planet went behind its star.
That dip was enough to allow the astronomers to take the temperature of these planets and confirm that they are hot, as predicted: about 1,450 degrees Fahrenheit for TrES-1 and about 1,570 degrees for HD 209458b.
Other results were more puzzling. For one thing, the TrES-1 planet seems to be emitting less light at shorter infrared wavelengths than the models of such planets predict, said Dr. Charbonneau, perhaps because greater-than-expected amounts of carbon monoxide are absorbing those wavelengths.
But as Dr. Charbonneau said, theoretical predictions about extrasolar planets have turned out to be "nothing short of disastrous." The field, he said, is driven by data, and there has not been much of that until now.
Dr. Boss noted that the Spitzer telescope had been designed decades ago and was never intended to study extrasolar planets. He also said that NASA had a whole menu of "wonderful" planet-finding missions.
"Just think of the results we will have from NASA's future telescopes that will be specifically designed to detect and study extrasolar planets," he said.
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Ahh yes, cause lord knows we are the top of the "it" chain in the vast....boundless....limitless ....unexplored galaxy after unexplored galaxy. Yes, theres NOTHING out there that can compare to "us" and how WE live. How narrow minded
No need to get snippy..
If you go, make sure you bring plenty of Coppertone.
It's kind of surprising to me that we've never gotten a glimpse of an alien planet with our big fancy telescopes and such.
Okay, that just sounds bad.
interesting
Can't be alien planets.
Has to be undocumented worker planets.
Gotta be up on this PC stuff.
"Rare Earth....astronomical constraints on advanced life.
The book's thesis is that advanced life may be extremely rare due to: 1) the many potential hazards in the universe and 2) the stringent requirements for its existence."
http://www.discovery.org/scripts/viewDB/index.php?command=view&id=147
Its probably the hot weather in orleans. I know, im from there.
Pics?
Unfortunately, there was just text. If there were pics, I almost always post them. Can you see infrared?
Re: "probably unfit for the kind of life found on Earth."
It just means they dislike MTV...not a bad thing.
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