Astronomers have taken the first pictures of planets outside our solar system, according to reports to be published tomorrow by the journal Science.

A team of astronomers led by Paul Kalas of the University of California at Berkeley used the Hubble Space Telescope to capture an image of a planet orbiting Fomalhaut, a star with about twice the mass of the sun located 25 light-years away from Earth in the constellation Piscus

Austrinus- A second group, led by Christian Marois of the National Research Council of Canada's Herzberg Institute of Astrophysics, used telescopes at the W.M. Keck Observatory atop Mauna Kea in Hawaii to take pictures of three planets orbiting a star called HR8799, about 140 light-years away in the constellation of Pegasus.  

Kalas said he ``nearly had a heart attack'' when he confirmed he had an image of a so-called exosolar planet. His colleague, Eugene Chiang, the lead author of an accompanying study to be published in The Astrophysical Journal, ``had to sit down'' when he saw the photograph, Kalas said.

To our eyes, we've never seen a planet moving around another star,'' Kalas said in a telephone interview. So it's a unique experience.''

Dust Raises Questions - Kalas's team first suspected there was a planet orbiting Fomalhaut in 2004, when images taken with a Hubble instrument showed a sharp edge to a circle of dust around the star. The edge suggested that the gravity created by a planet-like object was shaping the circle, clearing away particles in a manner similar to how the moons of Saturn groom the edges of its rings.

The astronomers trained Hubble's Advanced Camera for Surveys on the Fomalhaut system again in 2006. The images showed the object's movement over 21 months to be the same as what would be expected from a planet orbiting Fomalhaut every 872 years at a distance of about 119 astronomical units.

An astronomical unit is equal to about 93 million miles, or the distance from the Earth to its sun.  We often find suspicious objects which end up being false positives,'' Kalas said in a telephone interview Nov. 11. ``I was happy at first but careful, so I spent the next three days excluding all other possibilities. It was so exciting to see a planet in motion around another star.''

Other Objects Pondered - More than 322 exosolar planets have been detected so far, and astronomers have taken other pictures of possible planets outside the solar system with infrared systems since 2004. However, those objects have masses equal to five Jupiters or greater, suggesting they may be brown dwarves, or failed stars, Kalas said. Jupiter is about 11 times the size of Earth.

The new planet, a gas giant with a mass close to that of Jupiter that Kalas named Fomalhaut-b, can't be seen with infrared. Its low mass and the distance from its parent star make it impossible to detect with the current method, which measures a change in stellar light to find celestial bodies.

Fomalhaut-b may be visible because Saturn-like rings surrounding it are reflecting light from its parent star, Kalas said. The planet may resemble Jupiter and Saturn when our solar system was 100 million years old.

The discovery may prove to be the ``Rosetta Stone'' that allows astronomers to find similar planets in other dust rings around stars, said Marc Kuchner, an exoplanet scientist with NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Caught a Whale - It's almost like they went fishing in a fishbowl and they pulled out a whale,'' Kuchner said. ``It's a very massive planet located far from a star where planets shouldn't be.''

Marois' team studied the three-planet solar system with adaptive optics on the Keck telescopes, which help minimize the blurring effects of the Earth's atmosphere, and used a computer processing technique to separate the objects from the glare of their parent star.

The three planets have masses between seven and 10 times that of Jupiter and orbit between 24 and 67 astronomical units away from HR8799, which is about 1.5 times the size of the Earth's sun.

Both discoveries are going to force us to question what we know about planets,'' Sara Seager, associate professor of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology in Cambridge, Massachusetts, said in today's briefing.

Astronomers believe Earth and the other planets formed from a ring of gas and dust that surrounded the sun after its formation about 4.5 billion years ago, and study other stars and planetary systems to help determine how the solar system evolved and life began on Earth.

`Holy Grail' - The holy grail of this whole business is to detect Earth- like planets around mature stars,'' Kalas said. ``Fomalhaut-b is a step in the right direction. We're proving a concept, that if you devote enough time with Hubble you can get these remarkable discoveries. Technically, this discovery could have been made many years ago if Hubble had been used to look at Fomalhaut for an extended period of time.''

The papers will be published on Science Express, a Web site that posts articles before they are printed in the journal Science.  Kalas's research was sponsored by the National Science Foundation and the U.S. National Aeronautics and Space Administration. Marois' work was supported by NASA and the Mount Cuba Astronomical Foundation.