Windows to the past
In his previous research,
Liou has taken what he's learned about our solar system's dust and modeled how
giant planets, in general, leave their mark on it. These signatures could reveal
the presence of an extrasolar Jupiter-sized planet, which cannot be directly
imaged with current technology.
Liou says dust around a
star that harbors no large planets will be evenly distributed. But a planet
the size of Neptune or bigger will create an arc-like structure where the dust
piles up. The features should be identifiable with infrared telescopes already
in operation.
Liou has a candidate star
in mind, called Epsilon Eridani, whose dust disk was imaged by other researchers
in 1998.
Epsilon Eridani is just
10 light-years away, thus fairly easy to study. One of the astronomers who found
its disk, Jane Greaves of the University of Hawaii, said the star is a strong
candidate to harbor planets. But because Epsilon Eridani is young compared with
our Sun, comets and asteroids would likely heavily bombard any planets, just
as the young Earth was struck, she said. No one has confirmed there are any
planets there yet.
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Other astronomers agree
that Epsilon Eridani may be a window to the past, though, a view of our solar
system some four billion years ago, shortly after the planets formed. And Liou's
computer simulations highlight the similarities.
"The characteristics
of that disk are very similar to those from our simulations of the Edgeworth-Kuiper
Belt dust disk," Liou said.
The window that Landgraf
and Liou are polishing should help other researchers who hunt for planets around
Epsilon Eridani and the many, many similar stars that are also relatively nearby.
Ray Jayawardhana at the
University of California at Berkeley searches
for infant Jupiter-sized planets around young stars. Working on a team separate
from Greaves', he also helped discover the dust disk around Epsilon Eridani.
While the computer simulations of Landgraf and Liou involve mature solar systems
like our own, Jayawardhana told SPACE.com that there are many parallels.
And Jayawardhana agrees
with the new assessment of how dust is generated around our star and others.
A better understanding of
this process "allows comparisons with other solar systems, which will shed
light on the overall diversity of planet formation," said Jayawardhana.
"We can learn about other planetary systems by studying our own and vice
versa."
All this knowledge may even
help in the search for Earth-like planets.
Future space telescopes
will hunt for worlds that reside in the hole of a dust disk, near enough the
star to provide a potentially habitable climate, just as Earth does. While such
planets would not leave strong signatures in the dust, the character of the
disk could indicate that they might exist.
"By knowing what to
expect from the dust disks, we can help to design the planet-finding missions
to account for their effects," Landgraf said.
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