Research Interests

 
 

Currently, my research interests branch out into three broad categories:

  1. SMOOTHED PARTICLE HYDRODYNAMICS SIMULATIONS OF PROTOPLANETARY DISCS

  2. Collaborators: Ken Rice, Dimitris Stamatellos, Anthony Whitworth, Phil Armitage, Paul Clark, Peter Cossins, Giuseppe Lodato, Amaury Triaud

Protoplanetary Discs are frisbees of matter formed around stars at the same time that solar systems are born.  They are the spawning grounds of the planets - we must unlock their secrets if we are to understand the solar systems we see in our Galaxy.  Can discs form planets by fragmentation of the disc? We must explore how the instability varies with mass, radius, and thermodynamic regimes to answer this question fully.

I use SPH simulations to study the evolution of these discs, in particular studying the evolution of gravitational instability. I have augmented SPH with a radiative transfer algorithm to better model the disc thermodynamics.  We couple this with a basic equation of state to model the physical chemistry of the gas.  This is done at a minimal computational cost. 

  1. MONTE CARLO RADIATIVE TRANSFER AND IMAGING IN PROTOPLANETARY DISCS

  2. Collaborators: Ken Rice, Jane Greaves, Bruce Sibthorpe

Monte Carlo Radiative Transfer tracks the passage of photons through a medium using stochastic methods.  It is especially useful for hydrodynamic simulations as it allows the effects of a non-trivial density distribution to be traced.  We can then use the photons’ absorption and scattering in the medium to both reconstruct the system’s temperature distribution and create an image of the system (much like real telescopes image the heavens).

I have been using this method in protostellar disc scenarios.  In particular, I have been adapting this method for use in SPH density fields (typically, the method requires a density grid to operate - I have devised a method by which such gridding is not required).  This allows us to create observational signatures from our simulations, connecting us directly to observers.

SPH

MCRT

  1. NUMERICAL ASTROBIOLOGY AND COMPUTATIONAL METHODS IN SETI

  2. Collaborators: Vladimir Bozhilov, Jonathan Starling, Martin Elvis, Jonti Horner, Barrie Jones, Ken Rice, Milan Cirkovic, Branislav Vukotic, Bob Nichol

The Search for Extraterrestrial Intelligence (SETI) has been largely influenced by the original numerical analyses of Frank Drake and Enrico Fermi (viz. the Drake Equation and Fermi’s Paradox respectively).  The current influx of data regarding extrasolar planets is providing new information to these arguments, but specific data is difficult to incorporate into such simplistic models.

I have developed a means of quantifying the number of intelligent civilisations in the Galaxy over its lifetime, using Monte Carlo Realisation Techniques.  Its advantage over traditional methods is that new exoplanet data can be incorporated immediately into its framework, and different hypotheses for the origin of life can hence be compared. 

  1. LATITUDINAL ENERGY BALANCE MODELS OF EXOPLANETS

  2. Collaborators: Caleb Scharf, David Kipping

Latitudinal Equilibrium Balance Models (LEBMs) allow us to make a simple facsimile of terrestrial exoplanet climates.  By balancing the energy input from solar radiation with the output from infrared cooling, and adding in simple prescriptions for albedo and heat capacity, we can produce pseudo-Earth models which reproduce the average temperature profile quite well.

I have been using this model to investigate how terrestrial planets respond to unusual radiation patterns, such as those experienced in a binary star system like Alpha Centauri.  In future, I hope to explore other exotic planetary architectures that could host planets with unique habitability patterns.