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black hole has not, of course, been Ghez's only major find. It's
just her most recent. Using the same "infrared speckle interferometry"
technique she, in 1993, found that contrary to prior assumptions,
most stars form with a twin, located at distances smaller than that
of our solar system. Theories on star formation have typically been
based on single-star systems such as our own, despite the fact that
in our solar neighborhood, about half of the middle-aged stars have
companions. Many astronomers believed that these stars had begun
solo and then, by the process of capture, had become binary later
used her technique to look at young stars, anticipating she would
find either no binaries -- meaning the capture theory was correct
-- or the same proportion found in middle-aged stars, suggesting
companions emerge in the process of star formation. Instead, she
found twice as many companions in the younger stars.
you look at a stellar nursery, you see almost all binary stars,
and when you see the middle-aged stars like our sun, about half
of them are in binary star systems. So there's a discrepancy," Ghez
says. "There are two models, I think, to possibly explain it. Either
all of these systems form as multiple systems and then fall apart
by the time they get to the age of our sun, or some systems just
form stars more efficiently than others."
reverberations of her discovery were immediate: For one thing, "this
suggests there might not be as many planets as one might otherwise
think," Ghez observes, since the gravity of twin suns likely would
unhinge the neat ring of stardust from which planets are formed.
of these stars are actually separated by the distance between our
sun and just inside of, say, Pluto. So they are very close. And
the second star is going to disrupt the gas and dust, so I think
it's unlikely that the very closest binary systems are capable of
forming stable planetary systems," she says.