Re: [thefixedstars] Yahoo! News Story - Planet Formation is Child's Play - Yahoo! News
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> Planet Formation is Child's Play - Yahoo! News
Mark A. Holmes
Planet Formation is Child's Play
SPACE.com Thu Nov 29, 5:00 PM ET
Astronomers think they have found the two youngest
solar systems ever detected, where infant planets
could be sweeping up dust and creating voids in
protoplanetary disks 450 light-years from Earth.
NASA's Spitzer Space Telescope observed the ring-like
gaps, which could signal the earliest signs of rocky
planet formation around two young stars located in the
constellation TaurusUX Tau A and LkCa 15. Both stars
are about 1 million years old, which is 10 times
younger than other known planet-forming systems.
"Previously, astronomers were seeing holes at the
centers of protoplanetary disks," said Catherine
Espaillat, an astronomer at the University of Michigan
in Ann Arbor. Such holes are typically thought to be
caused by photoevaporation, or stars burning dust away
into light energy.
But instead of central holes, Espaillat's team saw
ring-like gaps in the spinning planetary materials.
"It's more like a lane has been cleared within the
disk. The existence of planets is the most probable
theory that can explain this structure," she said, as
the lanes are likely too distant from the star to
The idea is similar to touching a dusty record as it
rotates, clearing a ring in the mat of particles;
planets, however, use their growing gravity to sweep
up the dust.
The Dec. 1 issue of Astrophysical Journal Letters will
detail Espaillat and her colleagues' findings about
the infant solar systems, which they said could help
explain our own planet's past.
"We are looking for our history," said University of
Michigan astronomer Nuria Calvet, who worked with
Espaillat on the research. "We are looking for the
history of solar systems, trying to understand how
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