Distant SuperFlares Found On Stars
Disturbingly Similar To Our Own Sun
(Thanks to Steve Moser)

By Kathy Sawyer
Washington Post Staff Writer
Thursday, January 7, 1999
 
Astronomers announced today that they have found explosive outbursts of dazzling light and deadly rays occurring about once a century in nine stars "disturbingly similar to our own sun."

But Bradley E. Schaefer of Yale University, one of the researchers who made the discovery, repeatedly emphasized that "our sun does not do this, as far as we can tell." At least there is no evidence that such a thing has occurred in our solar system in the last billion or so years, he said.

But he added, "We are dealing with a variety of uncertainties here."

If such an event did occur on the sun, he speculated that it could at the very least destroy all satellite electronics, blow out power grids around the world, create spectacular displays of aurora even in tropical latitudes, and break up the ionosphere enough to prevent long-distance radio communications.

A larger flare would melt the surfaces of the icy moons around Saturn, forming flood plains over one hemisphere before freezing smooth again. Comfortingly, Schaefer said, no such topography has yet been detected.

In a worst-case scenario, the most powerful category of "superflare" would create "a complete global ozone hole that would last a couple of years," exposing Earth to the sun's ultraviolet radiation and "you'd basically kill the food chain from the bottom up," Schaefer said at the annual winter meeting of the American Astronomical Society.

Schaefer's team found this pattern of superflares on sunlike stars by analyzing historical records accumulated by others. The superflares, all at least 100 light-years away, Schaefer said, have been detected using a wide range of astronomical techniques.

The superflares range from roughly 100 to 10 million times the energies of the largest flare ever detected on the surface of the sun, Schaefer said. Unlike the relatively familiar solar eruptions on Earth's star, the newly identified superflares affect not just a given point on the surface but the entire star and then some.

At top energy levels, Schaefer said, "It could turn a cold winter day into a hot summer day."

Such high-energy flares have long been known to occur in younger stars, pairs of stars, fast-rotating stars and so on. The surprise was to find them in supposedly "normal" stars like the sun.

Why not the sun too? The answer may lie in the geometry of its planets. Schaefer's Yale colleague, Eric P. Rubenstein, suggested that the outbursts on sunlike stars may be stirred up when their magnetic fields get twisted up with the magnetic fields of nearby giant gas-ball planets, like Jupiter or Saturn. In the sun's case, Jupiter is much too far away to be a factor.

Schaefer said he is reassured about the sun's immunity from these hour-long events not only by the lack of evidence on the moons of Saturn but also because "any superflare in the last 150 years of scientific monitoring . . . would definitely have been recognized." And there are no records indicating a bright or oddly colored sun, a short intense heat wave or a world-spanning aurora.

Astronomers at the meeting also reported evidence that the cosmos might be peppered with an as-yet undetected population of dim, primeval galaxies resembling cannonballs, dense with matter but with few visible stars. Such galaxies might actually outnumber the more easily detected galaxies bright with shining stars, according to John Kormendy, of the University of Hawaii, and Kenneth Freeman of the Australian National University.

Astronomers said the cannonball galaxies may provide another piece in the cosmic puzzle of the so-called missing matter that makes up at least 90 percent of the universe that they have been unable to identify.

© Copyright 1999 The Washington Post Company
 


And The Same Story From Another View

Is Our Sun Safe?
DEATH FLARES

Discover Magazine April 1999

Yale astronomer Bradley Schaefer has some interesting news for those of us who live on Earth. He recently discovered that several nearby stars that closely resemble our sun can become violent, shooting off flares powerful enough to fry a planet more than a billion miles away. "These things are 100 to 10 million times larger than the biggest solar flares ever seen," Schaefer says.

A quirk of cosmic architecture apparently saves us from such fires. Schaefer's Yale colleague Eric Rubenstein theorizes that the magnetic field of a large planet orbiting close to a star may cause the flares. The planet's field could become entangled with the star's own magnetic field. When the twisted fields snap apart, the stored energy is released in one tremendous burst, creating what Rubenstein and Schaefer call a superflare.

The planet closest to our sun is  tiny Mercury, which has a very weak magnetic field. But if Jupiter occupied Mercury's orbit, we'd be in trouble. Schaefer says Jupiter would then be in a position to trigger a gargantuan flare that would turn winter into summer on Earth and strip away the atmosphere's protective ozone layer. "Ultraviolet radiation would bathe the entire globe, causing the food chain to die from the bottom up," he says. "I wouldn't want to be around."


Would you like to bet on the preceeding author's assumption that it can't happen here? Don't under estimate the power of our Sun and don't over estimate the reliability of such statements!