Hanno Rein

My name is Hanno Rein and this is my academic website. Since 2013, I am an Assistant Professor at the University of Toronto. I am a member of the Department for Physical and Environmental Sciences. My graduate appointments are at the Department of Astronomy and Astrophysics and the Department of Physics. My research interests are broad. They include planet formation, stochastic processes, planet migration, celestial mechanics, Saturn's rings, N-body codes, hydrodynamics, code development and high performance computing. Numerical methods are a big passion of mine.

Make sure to check out my REBOUND code. It is the only publicly available collisional N-body code. You can do almost anything with it from long-term symplectic orbit integrations to shearing-sheet simulations of Saturn's rings. The installation takes literally 30 seconds. It's really cool and I'm very proud of it.

You also don't want to miss the Exoplanet App. It is a free smartphone application for the iPhone/iPad that I wrote. It let's you explore almost the entire universe, including the cosmic microwave background, galaxy clusters, our Milky Way, the Solar System and all discovered extra-solar planets. Several million people have downloaded it already!

Contact details

You want to contact me? Awesome!

My mailing address is:
University of Toronto at Scarborough
Department for Physical and Environmental Sciences
1265 Military Trail
Toronto, Ontario M1C 1A4
Telephone (office):
(+1) 416-287-7206
(+1) 416-978-4582
Telephone (google voice):
(+1) 609-616-2213
hanno.rein (-at-) utoronto.ca
Office (Scarborough Campus):
Science Wing, S504C
Office (St George Campus):
Hanno Rein

New paper on high order integrator IAS15

We describe a new, high order integrator for gravitational dynamics that can handle both conservative and non-conservative forces. We ran a lot of tests and all results seem to show that our algorithm is superior to other integrators, including mixed variable symplectic integrators such as the one by Wisdom and Holman and other high order non-symplectic integrators, for example Bulirsch-Stoer. We took great care when implementing the scheme and achieve Brouwer's law (accuracy up to machine precision) for at least a billion orbits, equivalent to 10^11 timesteps. The scheme comes with adaptive timestepping and works extremely well on a wide range of problems with out-of-the-box setting and no fine-tuning of any parameters. This includes long term integrations of planetary systems, close encounters, Kozai cycles, migrating planets and dust undergoing PR-drag. You can find the preprint at http://arxiv.org/abs/1409.4779.

Research Group

Current postdocs: Dan Tamayo (CPS).
Current students: Caden Armstrong, Bryce Bolin, Sunny Chen, Patrick Fraser, Aleksandar Rachkov, Ari Silburt.
Past students: Eric Dapp, Shang-Fei Liu, Srivathsan Morkonda, Trevor Vincent, Quentin Xue.
Hanno Rein

Open Exoplanet Catalogue

Check out the Open Exoplanet Catalogue! It's a new kind of astronomical database: open, community driven and decentralized. Send me a message if you have any question or want to contribute to it but don't know how!

Links to scientific publications

You can find all my publication on this website.

Alternatively, you can search the NASA Astrophysics Data System (ADS) or the arXiv preprint server.

I feel very strongly about open access. All my publication are on the arXiv and you can access them free of charge. If you also think publicly funded research should be freely available for everyone on this planet, please do the same. Please also consider signing a petition against Elsevier.

New students

There are funind opportunities available for students interested in a MSc or PhD. Please talk to me to get a list of possible projects.


Past and present collaborators in alphabetical order:

Eugene Chiang, Eric Ford, Yuka Fujii, Willy Kley, Eiichiro Kokubo, Marc Kuchner, Henrik Latter, Zoe Leinhardt, Geoffroy Lesur, Shang-Fei Liu, Wladimir Lyra, Leonidas Moustakas, Gordon Ogilvie, Margaret Pan, John Papaloizou, David Spiegel, Scott Tremaine, Dimitri Veras.

Short academic curriculum vitae

Assistant Professor
2013 - now, University of Toronto, Canada
Member at the Institute for Advanced Study
2010 - 2013, Institute for Advanced Study, Princeton, US
PhD, Doctor of Philosophy
2007 - 2010, University of Cambridge, DAMTP, England
Thesis: The effects of stochastic forces on the evolution of planetary systems and Saturn's rings
Supervisor: Professor John C. B. Papaloizou
MASt, Master of Advanced Study, Part III of the Mathemtical Tripos
2006 - 2007, University of Cambridge, DAMTP, England
With distinction
Exams: General Relativity, String Theory, Quantum Field Theory, Advanced Quantum Field Theory, Black Holes
Essay: Finite time singularities (with Stephen J. Cowley)
Undegratuate studies in both Mathematics and Physics
2003 - 2006, University of Tuebingen, Germany


This is a screenshot of my collisional N-body code REBOUND. It can do so many things, there wasn't enough space on the main page to describe it. You therefore need to click on the link below. Or even better: just go over to github and try it out.

Find out more about REBOUND!


Connaught New Researcher Award (2014)
Funded by: The Connaught Fund
NSERC Discovery Grant (2014-2020)
Funded by: The Natural Sciences and Engineering Research Council of Canada
Exoplanet Smartphone App (2012)
Funded by: The Royal Astronomical Society, London
Principal investigator: Hanno Rein
Propellers, Frogs, and Random Walks (2012)
Funded by: NASA, ROSES-11, Outer Planets Research Program
Principal investigator: Eugene Chiang
Collaborators: Hanno Rein, Matthew Tiscareno, Margaret Pan
Hanno Rein

Exoplanet App

Over the last few years, I developed a very successful smartphone application called Exoplanet. It has attracted almost ten million (!) users and received outstandingly positive reviews. The application lists all extra-solar planets, features three dimensional visualizations and an interactive model of the Milky Way. The user can zoom out from the solar system all the way to the cosmic microwave background. An enormous amount of supplementary data from the Hipparcos catalogue, the 2MASS survey, WMAP and other missions is included in the app. This is like Google Earth, but for the entire universe. When a new planet is found and added to the database users receive a push notification. With about one million users already signed up for these notifications, it is a huge driving force in announcing new discoveries to the public. I was recently awarded an outreach grant from the Royal Astronomical Society in London specifically for the Exoplanet App.

Download the Exoplanet app now!