The primary focus of Dr. Zuckerman's recent research is the origin and
evolution of planetary systems. Along with his students and other
research colleagues he has been investigating material in planetary
systems that orbit around stars in a wide variety of evolutionary states
and with ages that range from as young as 8 million years to as old as
billions of years. In particular, the systems under investigation
include some that are pre-main sequence, some on the main sequence, some
post-main sequence giant stars, and some white dwarfs. The planetary
systems under investigation include some types never before seen in
astronomy.
The observational techniques utilized in the various programs include
optical spectroscopy, infrared photometry, infrared and microwave imaging
and X-ray photometry. Discoveries include the first images of extrasolar
planets orbiting around brown dwarfs and around stars (other than the Sun)
and the first reasonably good evidence for rocky planets orbiting an old
extrasolar star. The evidence for the latter is somewhat indirect and
consists of detection of the huge quantities of dusty debris resulting
from collision of two old rocky planets, much as if Mercury should wander
out of its orbit and collide with Venus or Earth. As part of a different
research project, the bulk elemental composition of ancient extrasolar
asteroids was measured using the photospheres of "polluted" white dwarfs
as detectors for material that previously resided inside of asteroids.
There exists no other technique in astronomy capable of measuring the
composition of such minor (low mass) extrasolar planetary bodies.