The New York Times, 10/20/1995

2 Astronomer Teams Sight Planet Orbiting Sunlike Star

By John Noble Wilford

Two teams of astronomers have made independent observations that they say establish for the first time the existence of a planet around a star similar to the Sun. The planet appears to be an object at least half the mass of Jupiter and is orbiting the star 51 Pegasus, only 40 light-years away from Earth.

If these sightings are borne out by further research, the discovery would have profound philosophical as well as scientific implications. It would remove any pretension that the solar system is unique. And the likelihood that there are many other planetary systems increases the chances of there being life -- perhaps intelligent life -- somewhere else in the universe. The discoverers do not know if the Pegasus planet is a solid or gaseous body, or if it is alone or has planetary companions. They are not sure if the planet has always been in its present orbit, or if collisions with other planets and the star's gravity drew it within five million miles of its star. They do know that its behavior is unlike anything in the solar system; being so close, it races around its star once every four days, compared with the 88-day orbit of Mercury, which at 36 million miles is the nearest planet to the Sun. Earth is 93 million miles from the Sun.

The star 51 Pegasus would look much like the Sun to an accupant of any planet it might have at a distance comparable with Earth's from the Sun. Its age is about eight billion years; the Sun's is five billion years.

At first, when Swiss astronomers announced their observations on Oct. 6, other scientists reacted with caution, even skepticism. They believe that extra-solar planets may be common, but many previous announced discoveries had vanished upon closer examination. Then two American astronomers, working at the Lick Observatory near San Jose, Calif., took a look on four nights last week and comfirmed the discovery.

In announcing the new detections of the planet, Dr. Geoffrey Marcy, an astronomer at San Francisco State University, said: "We've explored all sorts of alternative explanations, and we've had the greatest minds in astronomy chiming in. Nothing else explains what we see."

With those comfirming detections, earlier skepticism has faded. Other astronomers were still puzzled by the apparent presence of such a massive planetary object so close to a star. They wondered if it could be a low-mass star or substellar object knows as brown dwarf, instead of a true planet. But they expressed confidence in the abilities and judgment of both research teams.

Dr. Stephen P. Maran, an astronomer at the Goddard Space Flight Center in Greenbelt, Md., said the discovery was gaining strong support among other astronomers. "This time it appears they have really found a planet," he said.

Dr. David C. Black, director of the Lunar and Planetary Institute in Houston, said: "It's an exciting discovery."

Astronomers also predicted that the discovery could be only the beginning of many others in a short time. Indeed, the weekly magazine Science News reported in its current issue the detection of another, much larger planet candidate orbiting the star GL229, about 30 light-years from Earth. (A light-year is the distance light travels in a year, or six trillion miles.) The discovery was made at the Palomar Observatory in California by astronomers from the California Institute of Technology.

Until now, the only accepted evidence for planets beyond the solar system centered on a dead star. Three years ago, Dr. Alexander Wolszczan, a radio astronomer at Pennsylvania State University, detected two and possibly three planets orbiting not an ordinary star like the Sun, but a dense, rapidly spinning remnant of an exploded star, known as a pulsar.

Planets of a dead star, however, are almost certainly inhospitable to life. But the newly discovered planet is also, astronomers said. Being so close to its star, the planet probably spends much of its orbit inside the star's outer atmosphere. The planet's temperature probably reaches 1,8000 degrees Fahrenheit. If the planet was a gaseous giant like Jupiter, some astronomers said, the heat might have long ago driven off all its hydrogen atmosphere.

Dr. Paul Butler, a researcher at the University of California at Berkeley, who worked with Dr. Marcy on the comfirming observations, said: "We don't know what the object's made of. But our back-to-the-envelope calculations suggest that a Jupiter could hang on to its hydrogen under those circumstances at 51 Pegasus."

The discovery was made by Michel Mayor and Dr. Didier Queloz of the Geneva Observatory in Switzerland and report earlier this month at a scientific conference in Florence, Italy. The star is visible to the unaided eye in the Northern Hemisphere, but not the planet. A slight but regular wobble in the motion of 51 Pegasus betrayed the gravitational effects of a nearby massive planet.

Dr. Butler and Dr. Marcy plan to return to Lick Observatory tonight for 10 consecutive nights examining 51 Pegasus. They want to conduct longer observations of the wobbling motions to refine their understanding of the planet's orbit and mass and look for the possible presence of other planets in the same system.




San Francisco Chronicle, 10/19/1995

Discovery Of Planet Confirmed

UC team finds it circling distant star

By David Perlman

After eight-year quest, astronomers at the University of California's Lick Observatory said yesterday that they have confirmed for the first time that an unknown planet is circling a star beyon\d the solar system.

The report, flashed through cyberspace to other astronomers around the world via the Internet, immediately sent scientists seeking to explain the new planet's bizarre behavior.

And it led one world-famed astronomer to speculate that despite the planet's temporature of nearly 2,000 degrees on its starlit side, its dark side might be cold enough to harbor living organisms--or at least the chemistry of life.

Improbable as that idea may be, other astronomers agree that the discovery marks a real revolutionby establishing for the first time that planetary systems do indeed exist elsewhere in our Milky Way galaxy, and thus that there may be many others with planets much like Earth.

Yesterday's report came from Geoffrey Marcy, professor of physics and astronomy at San Francisco State University who is a visiting scholar at the University of California at Berkeley, and his postdoctoral researcher, Paul Butler.

It was less than two weeks ago, Marcy said, that two astronomers--Michel Mayor and Didier Queloz of Switzerland's Geneva Observatory--reported at a meeting in Italy that they detected a strange planet-like object orbiting the relatively nearby star called 51 Pegasus, about 42 light years from Earth.

Marcy and Butler heard news of the possible find on the Internet, and because they were already schedule to spend the next four nights on their own planet search using the 120-inch telescope at the Lick Observatory atop Mount Hamilton near San Jose, they decided to target the powerful instrument on tha star in the well-known constellation Pegasus.

"We just went by that old yarn that if you lose a contact lens on a dark street, the best place to look for it is under the nearest street lamp, where the light's better," Marcy said. "And 51 Pegasus, we decided, was our street light."

For Marcy and Butler the decision was a stroke of luck.

"We'd been seriously hitting for distant planets for eight years," Marcy said. "And finally we were able to confirm that one really exists."

The planet itself is at least a million times fainter than its parent star, Marcy said, and far too dim to be visible. But its gravity is strong enough to perturbthe rotation of the stars, and by measuring those tiny irregular motions of the star with unparalleled precision night after night, Marcy and Butler calculated that the planet is speeding in orbit around 51 Pegasus at least half as massive as the giant planet Jupiter.

Despite its size, however, the planet's orbit is carrying it within 5 million miles if the star--mysteriously within the star's hot atmosphere, called the corona.

This raises several questions. How, for example, was the huge planet originally formed; how can it remain there so close to its "sun;" and why has not the murderous heat of the stellar corona vaporized it already?

Farflung astronomers were already puzzling over those questions at their computers yesterday, and one tentative answer came from Douglas N. C. Lin, an astrophysicist at UC Santa Cruz.

The planet is so massive, Lin calculated, that it could hold itself together despite its searing environment. Lin believes that it must have originated far out from its sun as a vast rotating disk of viscous gas and matter that slowly condensed under its own gravity and drew closer to the star--much like Jupiter might have done billion of years ago.

"In any event," Lin said, "this is an extremely important and exciting discovery that will help us learn much more about the formation of planetary systems."

Only once before has a team of astronomers detected planet-like objects outside the solar system. But they did it by observing radio waves from the densely packed matter of a whirling neutron--the dead remnants of a true star that had exploded long ago.

Alexander Wolszczan, an astrophysicist at Pennsylvania State University, is one of the scientists who discovered those objects and he agreed that the finding by Marcy and Butler are a crucial confirmation of the long-help belief that planetary systems must exist throoughout the universe.

"It's quite clear that this new finding is genuine," Wolszczan said, "but it also shows that planets can be bizarre objects indeed. The ones we confirmed last year turned out to be orbiting a neutron star, and now we find a new one orbiting very rapidly right inside a star's own hot corona. So we've been surprised twice-- and we've better be ready to be surprised again."

Wolszczan maintained that the new-found planet is so massive and so close to its star that within an other million years or so it will eventually spiral down further and be swallowed up.

Not so, said Marcy yesterday. It is extremely likely, he said, that the planet is creating tides on the surface of its star just as the moon does on the surface of the Earth. And if that is so, then the planet could eventually spiral slowly outward away from the star, just as Earth's moon is spiraling outward even now.

The possibility of any life existing on the cold, darker side of the new-found planet may indeed be remote, said UC Santa Cruz astronomer Frank Drake--whoe 30- year search for life in interstellar space has given birth fo the international program called SETI, the Search for Extraterrestrial Intelligence.

"But you can always speculate," he said, "and the real importance of what they've found is that other planetary systems--which we've always insisted must exist without hard evidence--has now been proven. And if one such system exists, then there must be more. And somewhere, there's bound to be intelligent life that's capable of communicating."




The Florida Times Union, 10/19/1995

A New Planet Found

For the first time, astronomers have confirmed the discovery of a planet around a star similar to the sun.

The star, 51 Pegasus, is only 40 light years distant and visible to the naked eye in the northern hemisphere.

The long-awaited discovery of a planet in a system apparently similar to the solar system has made the fifth-magnitude star the focus of intense excitement as word spread this week that the findings had been verified independently.

Until now, the only unshakable evidence of planets outside the solar system had been found in a system that is dramatically different from the sun's.

The confirmation of the 51 Pegasus planet, about 160 times the mass of Earth, gives new credence to theories that there are other Earthlike worlds that could harbor life, said Geoffrey Marcy of San Francisco State University, whose team confirmed the discovery.

"It's wild," he said, "I'm getting 60 or 70 e-mails per day from astronomers all over the world."

The newly discovered planet's nature is certainly not compatible with life as we know it. Its orbit takes it within the star's fiery outer corona, where temperatures are about 1,800 degrees Fahrenheit.

Scientists mulling the evidence have speculated that there is a traditional system of planets in more distant orbital paths around 51 Pegasus.

"What this discovery does," Marcy said," is open up a whole new subfield of astrophysics in which we will study planetary systems."

Said Stephen Maran, spokesman for the American Astronomical Society: "This is a great day for all astronomers...It now appears that we have found one of the so-called holy grails."