Ralph Pudritz
Ralph Pudritz
ABB 318

I am a theoretical astrophysicist and my research focuses on star and planet formation. I completed my undergraduate studies at UBC in mathematics and physics. I then moved to the University of Toronto for my M. Sc. (in theoretical physics). I returned to UBC to do my Ph.D. in astrophysics under the supervision of Greg Fahlman, completing it in 1980. I took up an NSERC Postdoctoral Fellowship at the Institute of Astronomy in Cambridge (England). I went on to further postdoctoral research with Chris McKee and Jon Arons at the Astronomy Dept. at Berkeley, and with Colin Norman at the Johns Hopkins University. I joined the faculty at McMaster in 1986. Research Leaves and Fellowships over the subsequent years have taken me to many outstanding research centres including the Observatoire de Grenoble (1988, 1992), the Max-Planck Inst. for Astronomy in Heidelberg (1993), the Harvard-Smithsonian Center for Astrophysics (1993), the Max-Planck Institute for Astrophysics in Munich (1997), the Canadian Institute for Theoretical Astrophysics (CITA) in Toronto (1990 and 1997), Caltech (2001), and the Kavli Institute for Theoretical Physics (KITP) in Santa Barbara (2007/08).

I have been involved in many aspects of Canadian as well as international astronomy and astrophysics, having served on Time Allocation Committees (CFHT and JCMT), NRC Science Advisory Committees (Gemini, JWST), Visiting Committees (U.S. NRAO), Advisory Boards (HIA, CITA Council), and review committees. I chaired Canada's decadal survey of Astronomy and Astrophysics - the NRC-NSERC Long Range Planning Panel (1998/2000) - and was the principal author of the LRP report; "The Origins of Structure in the Universe". The LRP is playing the central role in guiding the development of Canadian astronomy in this decade and beyond, having involved Canada in ALMA, JWST, TMT, SKA, and several other important space and ground based telescopes and observatories.

Most recently, I spear-headed and am the founding (2004) Director of McMaster's Origins Institute (OI). Its scientific mission is to engage in fundamental transdisciplinary research on the origin of structure and life in the cosmos. The scientific themes of the OI cover 6 broad themes in science: the origin of space and time (cosmology, early universe), structure in the universe (planets, stars and galaxies), the elements, life (astrobiology), species and biodiversity, and humanity. In addition to its research foci, the OI has developed a novel OI Undergraduate Research specialization. The OI is committed to public outreach and education through its award winning OI Public Lecture series and played an important role in the creation of the McMaster 3D theatre. The OI has also run major international annual scientific conferences on some of the most important questions in contemporary science.

Star formation, planet formation, astrobiology

Department of Physics and Astronomy

I have taught a wide variety of undergraduate as well as graduate courses, in both astrophysics and physics. I have often taught graduate courses on Star Formation (Physics 778), the Interstellar Medium (Physics 785) and Galactic Dynamics (Physics 781). In the undergraduate program, I have often taught the Introductory Astronomy and Astrophysics course (Astron 1F03), first year physics, and upper level courses such Galaxies and Cosmology (Astron 3X03), and Stellar Structure (Astron 3Y03).

Origins Institute

I have worked extensively with my OI collaborators, Jonathon Stone and Alison Sills, to create and realize a new concept for teaching transdisciplinary courses in fundamental science. We designed the Origins Undergraduate Research Specialization to take students into the heart of 6 of the most fundamental streams of research in 21st century science. These subjects transcend the traditional subjects in science calendars, since these fields are often highly transdisciplinary. Our philosophy is to insure that students that are deeply trained in a particular field (hence requirement to be registered in a traditional Honours Science Program), are at the same time sufficiently immersed in the broad set of fundamental science themes that are emphasized in the OI programs.

This approach is accomplished by first having our students go through a set of survey courses in their first year of the program (e.g. Big Questions). Their interests are then sharpened in the second year of the program through a selection of courses centred on each of the 6 basic themes. All the while, we expose students to the fundamental literature and new scientific results in these fields by means of highly interactive seminars (Origins 2S03 and 3S03). The first of these is designed to take the students through the basic literature, guided by OI faculty. The 2nd year seminar exposes students to visiting scientists and their colloquia as part of the OI colloquium series. The capstone of the program is the OI undergraduate thesis, taken in the 3rd and final year of the program. Here the student is encouraged to work in any area that they have taken an interest in, and to seek appropriate OI supervisors. Our OI students are invited to meet with OI Public Lecturers to broaden their exposure to outstanding scientists at a very early stage in their careers.

I have personally developed and taught, in collaboration with Paul Higgs, the Origins of Life (Astrobiology - Origins 3D03) course. The OI is building a strong research presence in this field, and students participate in this very exciting, emergent new science.

Ralph Pudritz
Department of Physics & Astronomy
McMaster University

Dear Prospective Research Students:
My research interests focus on the theoretical and numerical study of star and planet formation, and the connection between the astrophysical basis for the origin of life on terrestrial planets. Both stars and planets form in protostellar disks and there are very deep connections between these subjects through them. Star formation impacts a huge range of astophysics - from planet formation to galaxy formation and evolution and cosmology. The discovery of more than 3000 exoplanets is driving a major revolution in astrophysics as we try to develop new theoretical models that can explain the wealth of new data and planetary populations – such as the dominant SuperEarths. The rise of astrochemistry and the  characterization of terrestrial planets is likewise driving new efforts in understanding the Origins of Life. Although research in my group emphasizes state of the art, high performance computing as well as theory, the advent of new observatories such as the James Webb Space Telescope, as well as the Atacama Large Millimeter Array (ALMA) allow us to connect the work with new observations.

There are many exciting research opportunities in my group. Group members use the latest computational and theoretical tools and there is a wide range of forefront problems in these areas. There is also a lot of interdisciplinary work as these problems seldom involve just one narrow subfield of astrophysics and can use ideas and tools from many areas of physics and chemistry. I have regular group meetings every week in which all aspects of the group’s research are discussed, so that students and postdocs at all levels are connected to one another and learn a great deal about related areas.

A summary of current research being carried out in my group:
My research in star formation explores a wide range of interconnected problems. Stars form primarily as members of star clusters within dense, filamentary, turbulent molecular clouds. My ultimate goal is to develop a seamless picture of star formation, starting from the scale of the formation of molecular clouds in galaxies, down to filamentary structure of molecular clouds, to the formation of star clusters within these clouds, to the collapse of individual gas “cores” within such clustered environments (to form single or binary stars), and on down to the scales that characterize the physics of protostellar disks through which gasaccretes onto their central stars and from which highly collimated jets are launched. Much of the research involves state of the art 3D numerical simulations using the FLASH Adaptive Mesh Refinement Code.

Here are some problems we’ve worked on recently:

Star formation in filamentary molecular clouds: see our review Andrè et al, (2014):
Radiative feedback and the formation of massive stars: Klassen, Pudritz et al (2016):
Radiative feedback and the formation of star clusters: Howard, Pudritz, & Harris ( 2017):
Theory and simulations of protostellar jets and outflows: see our review Pudritz et al (2007):

The formation of exoplanets and exoplanetary systems is arguably one of the hottest topics in astrophysics, and indeed science, today. In my group we are investigating all aspects of planet formation, connection how planets form in protostellar disks, to their final orbits and chemical compositions. This “end-to-end” approach can be used to predict the composition of exoplanet atmospheres, which will be observed for the first time with JWST. This research involves theoretical work, as well as extensive use of astrochemistry codes and population synthesis simulations. Some recent papers in my group include:

My research program on the origins of life focuses on the connection between protostellar disks, and the properties of pre-biotic chemistry on newly formed habitable planets. Nucleobases, amino acids, and fatty acids are found in meteorites and can be synthesized in 100 km parent bodies – planetesimals – which are also the building blocks of terrestrial planets. We have done calculations to show how these molecules are synthesized within planetesimals. Recent work focuses on understanding how meteoritic delivered biomolecules evolve on early planetary conditions, to result in the formation of RNA polymers – the first genetic materials. See our recent article:

I have many interesting research projects within this broad set of themes. I will be happy to discuss these with you. If you are interested, please send me e-mail at pudritz@physics.mcmaster.ca or consult my departmental home page. I look forward to hearing from you!

With best wishes,
Ralph Pudritz

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