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I am fascinated by the questions of how stars and planets form - arguably two of the most exciting and still largely unsolved major problems in contemporary astrophysics. Both of these problems are also major drivers for the question of how and where life originated in the cosmos.
> Star Formation
I began my research in star formation at Cambridge in
the early 1980s through work with Colin Norman on disk winds and the
origin of jets in protostellar systems. Since then, I have worked with my
students, postdocs and collaborators on many different and important
aspects of the general problem of star formation. My research to date has
focused on the formation of stars and protostellar disks through
gravitational collapse, the origin of jets and outflows from
accretion disks around young stars, turbulence and the origin of structure
and stars
in molecular clouds, the origin of the spectrum of stellar masses (the
so-called IMF), the
formation of star clusters and globular clusters,
the origin of magnetic fields in galaxies, and
the origin of globular cluster-forming clouds in the early universe.
Hydrodynamics and sometimes hydromagnetic processes are at the heart of
much of structure formation in the cosmos, and my work uses these
techniques. In addition to theoretical modeling, we do very sophisticated
numerical simulations using High Performance Computing facilities provided
by SHARCNET.
Images
Simulations
Useful links
From Darkness to Light: Forming the Oldest Stars in the Cosmos (Press Release)
Astronomers find magnetic Slinky in Orion (Confirmation of torodial magnetic fields, Press Release), and the McMaster press release.
> Planet Formation
I have extended my research interests into the problem of how planets form
and migrate in their natal
disks. This is an especially important topic given the
discovery of over 250 exosolar Jovian-mass (mainly) planets, most of
which orbit very close to their central stars.
Planet formation is tightly
linked with the process of star formation since both stars and planets form in
gaseous protostellar disks which have been observed around all young
stars. We have shown how the presence of dead zones in the inner regions
of protostellar disks regions of very low disk viscosity can prevent the
rapid loss of entire planetary systems by plunging into their central
stars via their rapid migration through disks. The interaction of young
forming planets with their surrounding gaseous disks is a very important
question that is the focus of much of our planetary research.
Images
Useful links
Saving Planetary Systems: Dead Zones to the Rescue (New Scientist)
> Astrobiology
Related to the origin of stars and planets is another of the most
fundamental and exciting problems in science - the origins of life.
Astrophysics has a great deal to say about this important question as
astronomers begin to search for planets of terrestrial mass (the lowest so
far is 5 Earth masses) and learn how to probe the atmospheres of exosolar
planets. Meteoritic evidence shows that these bodies are laden with amino
acids and other key biomolecules. The Earth's ocean was probably delivered by
impacts of meteorites that formed in water-ice rich regions
of the early Solar Nebula, at around 2-3 Astronomical Units. Through the OI programs, I have begun working on the question of
how processes in protoplanetary disks resulted in the creation of
habitable planets complete with their supplies of water and biomolecules.
Please see publications for recent papers, talks, and books I have given
or written on these topics. See also our recent book Planetary Systems and
the Origins of Life published by Cambridge University Press.
Useful links
Origin of Life on Earth (Leslie E. Orgel)
wapedia: Abiogenesis
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