ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Sunday, April 14, 1996 TAG: 9604150127
SECTION: NATIONAL/INTERNATIONAL PAGE: A8 EDITION: METRO
DATELINE: WASHINGTON
SOURCE: THE WASHINGTON POST
Astronomers in California say they have found another planet around a sun- like star, this time in the constellation Cancer, the Crab.
The discovery brings the total score to five new planets - or superplanets - detected in Earth's neighborhood around stars similar to the sun since the first one was reported a scant six months ago.
``It seems as if we're entering the planet-a-month era,'' said co-discoverer Paul Butler, a researcher with a joint appointment at San Francisco State University and the University of California, Berkeley. He and colleague Geoffrey Marcy, also of San Francisco State and a visiting scholar at Berkeley, in January reported the detection of two Jupiter-class objects that could harbor water and other building blocks of life.
The new planet, confirmed by Butler and Marcy in observations made last weekend, is in orbit around a Magnitude 6 star about 45 light-years from Earth that, under the right conditions, is visible to the naked eye, Butler said. And it is strikingly similar to the first planet ever detected around a sun-like star, which was announced by a Swiss team in October and was at the time considered an unbelievable oddball.
The star is 55 rho Cancri, in the northern portion of the constellation, astronomers said. Its planet, like the first ``oddball,'' is about the mass of Jupiter, and orbits very close to its star - in this case, one-tenth the distance from Earth to the sun, and three times closer than Mercury, or less than 10 million miles.
That is about twice as far out as the first planet discovered, which circles its star so tightly that it passes within the fiery outer corona.
This shows that the first one ``is not a fluke,'' said Butler, ``and people had not predicted this.'' Both planets are in ``blowtorch orbits'' where no life could form, he said. Astronomers previously considered such tight orbits too close to a star for a planet of such size to form. In fact, the discovery of the first one has triggered a cottage industry of researchers trying to explain mechanisms by which the planet turned up there in a stable orbit.
It is the very closeness of those two planets to their stars, and the speed with which they complete their orbits, that has enabled the astronomers to identify them with such certainty. They measured the Doppler shift in the stars' light to detect a wobble in the stars' motion caused by the tug of the planets' gravity.
Alan P. Boss of the Carnegie Institution in Washington, D.C., said, ``I think they've got another convincing detection of another giant planet.'' He attended a meeting of astronomers Thursday at the University of Maryland where Butler presented his data.
The consensus among theorists, Boss said, is that giant planets cannot form so close to their stars but must have spiraled in from farther out.
The finding makes clear that the other new planets found earlier ``are not curiosities, or freaks,'' said Stephen P. Maran, a spokesman for the American Astronomical Society. As new telescopes and other technologies open for business in Texas, Hawaii and Chile, he said, ``Planets are going to be popping out all over.''
Butler said there are hints in the data that there is a second planet in orbit around the same star in Cancer. If confirmed as a planet and not a second star or other gravitational influence, this would be the first multiple-planet ``system,'' like the solar system, to be detected around a sun-like star. The only confirmed evidence of planets outside the solar system, before October, had been in a system dramatically different from the sun's. In that case, at least two planets were detected in orbit around a whirling dead star called a pulsar, which emits a barrage of deadly invisible radiation instead of light.
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