From planet formation to thermodynamic constraints on the first genetic code
Ralph Pudritz
McMaster University
Protoplanetary disks provide the initial conditions for planet formation
as well as for their prebiotic states. In this talk I will examine both
aspects of planetary formation.
Standard models for planet formation in dusty, gaseous disks reveal that
planets rapidly migrate from their birth positions. This process is so
efficient that planets risk plunging into their central stars within a
million years. I shall review observations and ideas of what controls the
process of exoplanet formation and migration. I will then present our
recent simulations of migrating and accreting planets in radiatively
heated protostellar disks containing dead zones - regions where turbulence
is strongly suppressed. We have discovered that both the density and
thermal structure of disks with such regions act as effective brakes that
prevent the rapid loss of planets to their central stars.
The radiatively heated natal disks that produce planets may also be
significant factories for the synthesis of biomolecules such as amino
acids, which may be delivered to planets by cometary or meteoritic
bombardment. This is a very significant aspect of astrobiology. We have
recently discovered some general thermodynamic constraints on the
synthesis of amino acids in a variety of prebiotic environments. This
provides insight into the environments which produced biomolecules for
early life and possible constraints on the nature of the first genetic
code.
Date: | Jeudi, le 1 octobre 2009 |
Heure: | 11:30 |
Lieu: | Université de Montréal |
| Pavillon Roger-Gaudry, Local D-460 |
Contact: | Marie-Ève Naud |
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