John Landstreet, Western University
Physics And Astronomy Professor Emeritus London, Ontario jlandstr@uwo.ca
Bio/Research
I grew up mainly in the US, where I went to university (Reed College, in Portland, Oregon) and graduate school (Columbia University, in New York City, where I was in the Physics Department but did my thesis under Prof Lodewyk Woltjer, later well known as the long-time Director General of the Euro...
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Bio/Research
I grew up mainly in the US, where I went to university (Reed College, in Portland, Oregon) and graduate school (Columbia University, in New York City, where I was in the Physics Department but did my thesis under Prof Lodewyk Woltjer, later well known as the long-time Director General of the European Southern Observatory). In 1970 I moved to London, Canada, to a post at the University of Western Ontario (UWO), where I have been (except for three sabbaticals, one at the Institut fuer theoretische Astrophysik of the University of Heidelberg, and two (!) at l'Observatoire Midi-Pyrenees in Toulouse) ever since. I am married to artist Barbara Landstreet, and have two children (David, grown up, and Sarah, a mechanical engineering graduate from McGill University, who is starting her own business in Belfast, Northern Ireland ).
I am an emeritus/adjunct professor of physics and astronomy at UWO, where I often taught one section of the introductory astronomy course for poets, Astronomy 021. I also taught for some years the second year course in solar system physics (Astronomy 221/231), which I think is a great vehicle for reinforcing basic ideas from first-year physics. Recently I have taught the graduate level course in stellar interiors, and a number of courses on the physics side of our department. I have taught the third-year physics lab for several years, and various other courses such as fourth-year molecular and nuclear physics. At present, I am Leverhulme Visiting Professor at Armagh Observatory in Armagh, Northern Ireland
I have been active in the Canadian and international astronomical communities. I have been a member, Vice-Chair, and Chair of the Scientific Advisory Council of the Canada-France-Hawaii Telescope (1980 - 83), and more recently a member, Secretary, Vice-Chair, and Chair of the Board of Directors of the CFHT (1990 - 1997). I was President of Commission 25 (Photometry and Polarimetry) of the International Astronomical Union (1994 - 1997). I was a member and Chair of the Grant Selection Committee for Space and Astronomy (1980 - 83). I have been a member of the Board of Directors of the Canadian Astronomical Society (1994 - 1998), and served for two years as President. I am currently President of Commission 36 (Theory of Stellar Atmospheres) of the International Astronomical Union.
In the spring of 2002 I was awarded the C. S. Beals Award of the Canadian Astronomical Society. This is the highest research honour awarded by the Canadian astronomy community.
Research Interests:
Early in my career, I worked extensively with Roger Angel on magnetic fields in white dwarf stars. We were involved with Jim Kemp in the discovery of the first of these multi-megagauss fields in Grw +70 8247, and Roger and I did most of the early search and discovery work in this field for the next few years, before we both moved on to other projects.
More recently, I have been interested primarily in physical processes that occur in envelopes and atmospheres of upper main sequence A and B stars. I have searched for and measured magnetic fields in such stars extensively, using both polarimetry and spectroscopy. I have tried to clarify which types of A and B stars have strong, coherent magnetic fields, and which don't. I have also tried to find clues in the magnetic data about how the strong fields of the magnetic A and B stars evolve with time. I have worked on modelling magnetic field geometries using a variety of techniques. Recently I have been modelling both field structure and the distributions of chemical elements over the surfaces of magnetic stars from spectra using my own set of FORTRAN spectrum synthesis programmes for stellar atmospheres permeated by magnetic fields (yes, lots of working scientists actually use FORTRAN, in spite of much editorial comment from colleagues in computer science). An example of this work may be found in Landstreet, Barker, Bohlender and Jewison 1989, The magnetic field and abundance distribution geometry of the peculiar B star HD 215441, Ap. J., 344, 876.
I am an active observer. Over the years, I have used a lot of large telescopes, including the 82" and 107" telescopes at McDonald Observatory, the 84" and 4-m telescopes at Kitt Peak National Observatory, the 60 " and the Big Eye at Palomar Observatory, the 60" and 100" telescopes at Mount Wilson Observatory, the 2.5-m telescope at Las Campanas Observatory, the 2-m telescope at l'Observatoire du Pic-du-Midi and the 152-cm telescope at l'Observatoire de Haute Provence in France, and of course the 3.6-m Canada-France-Hawaii Telescope on Mauna Kea. Naturally, I also regularly use our own 1.2-m telescope at Elginfield. I have done a lot of photoelectric polarimetry in past years. I currently use the UWO Cassegrain photoelectric filter polarimeter at Elginfield and the Musicos spectropolarimeter at Pic-du-Midi, and I am also doing a lot of (very) high resolution stellar spectroscopy at present, much of it at the CFHT.
I have several current research interests. One is participation in a big mapping project to derive detailed maps of magnetic field structure and surface chemical element distributions over the surface of a number of known magnetic Ap stars, using wonderful new data obtained with the Musicos spectropolarimeter at Pic-du-Midi. A second project is to model individual line profiles in a number of very sharp-lined A and B stars, in an effort to detect directly the local line profiles of these stars, using high resolution, high signal-to-noise ratio spectra. This is an effort to see what information can be extracted from such profiles about conditions in the stellar atmosphere, particularly about the weak convection that may be present, and about the adequacy of LTE models to describe line formation in A and late B stars. A third project is an effort to find parametrized magnetic models for a large sample of new Ap star magnetic field measurements by Mathys and his collaborators, and to see what information about Ap magnetic fields is hidden in these data. And of course there are other projects waiting for a little time....
I am fortunate to be associated with (a perceptive person might even say "sustained by") an excellent research group, including one-time UWO undergraduate, now UWO Assistant Professor Aaron Sigut; and undergrads Anna Townshend and Jessie Silaj. I have some great international collaborations with, for example, former Ph D student, now Assistant Professor at the Royal Military College, Gregg Wade, Stefano Bagnulo at the European Southern Observatory, Jean-Francois Donati at l'Observatoire Midi-Pyrenees in Toulouse, and Gautier Mathys at the European Southern Observatory. And of course I depend heavily on excellent technical support from computer specialist Henry Leparskas and technician and instrument designer Mike Debruyne.
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I am an emeritus/adjunct professor of physics and astronomy at UWO, where I often taught one section of the introductory astronomy course for poets, Astronomy 021. I also taught for some years the second year course in solar system physics (Astronomy 221/231), which I think is a great vehicle for reinforcing basic ideas from first-year physics. Recently I have taught the graduate level course in stellar interiors, and a number of courses on the physics side of our department. I have taught the third-year physics lab for several years, and various other courses such as fourth-year molecular and nuclear physics. At present, I am Leverhulme Visiting Professor at Armagh Observatory in Armagh, Northern Ireland
I have been active in the Canadian and international astronomical communities. I have been a member, Vice-Chair, and Chair of the Scientific Advisory Council of the Canada-France-Hawaii Telescope (1980 - 83), and more recently a member, Secretary, Vice-Chair, and Chair of the Board of Directors of the CFHT (1990 - 1997). I was President of Commission 25 (Photometry and Polarimetry) of the International Astronomical Union (1994 - 1997). I was a member and Chair of the Grant Selection Committee for Space and Astronomy (1980 - 83). I have been a member of the Board of Directors of the Canadian Astronomical Society (1994 - 1998), and served for two years as President. I am currently President of Commission 36 (Theory of Stellar Atmospheres) of the International Astronomical Union.
In the spring of 2002 I was awarded the C. S. Beals Award of the Canadian Astronomical Society. This is the highest research honour awarded by the Canadian astronomy community.
Research Interests:
Early in my career, I worked extensively with Roger Angel on magnetic fields in white dwarf stars. We were involved with Jim Kemp in the discovery of the first of these multi-megagauss fields in Grw +70 8247, and Roger and I did most of the early search and discovery work in this field for the next few years, before we both moved on to other projects.
More recently, I have been interested primarily in physical processes that occur in envelopes and atmospheres of upper main sequence A and B stars. I have searched for and measured magnetic fields in such stars extensively, using both polarimetry and spectroscopy. I have tried to clarify which types of A and B stars have strong, coherent magnetic fields, and which don't. I have also tried to find clues in the magnetic data about how the strong fields of the magnetic A and B stars evolve with time. I have worked on modelling magnetic field geometries using a variety of techniques. Recently I have been modelling both field structure and the distributions of chemical elements over the surfaces of magnetic stars from spectra using my own set of FORTRAN spectrum synthesis programmes for stellar atmospheres permeated by magnetic fields (yes, lots of working scientists actually use FORTRAN, in spite of much editorial comment from colleagues in computer science). An example of this work may be found in Landstreet, Barker, Bohlender and Jewison 1989, The magnetic field and abundance distribution geometry of the peculiar B star HD 215441, Ap. J., 344, 876.
I am an active observer. Over the years, I have used a lot of large telescopes, including the 82" and 107" telescopes at McDonald Observatory, the 84" and 4-m telescopes at Kitt Peak National Observatory, the 60 " and the Big Eye at Palomar Observatory, the 60" and 100" telescopes at Mount Wilson Observatory, the 2.5-m telescope at Las Campanas Observatory, the 2-m telescope at l'Observatoire du Pic-du-Midi and the 152-cm telescope at l'Observatoire de Haute Provence in France, and of course the 3.6-m Canada-France-Hawaii Telescope on Mauna Kea. Naturally, I also regularly use our own 1.2-m telescope at Elginfield. I have done a lot of photoelectric polarimetry in past years. I currently use the UWO Cassegrain photoelectric filter polarimeter at Elginfield and the Musicos spectropolarimeter at Pic-du-Midi, and I am also doing a lot of (very) high resolution stellar spectroscopy at present, much of it at the CFHT.
I have several current research interests. One is participation in a big mapping project to derive detailed maps of magnetic field structure and surface chemical element distributions over the surface of a number of known magnetic Ap stars, using wonderful new data obtained with the Musicos spectropolarimeter at Pic-du-Midi. A second project is to model individual line profiles in a number of very sharp-lined A and B stars, in an effort to detect directly the local line profiles of these stars, using high resolution, high signal-to-noise ratio spectra. This is an effort to see what information can be extracted from such profiles about conditions in the stellar atmosphere, particularly about the weak convection that may be present, and about the adequacy of LTE models to describe line formation in A and late B stars. A third project is an effort to find parametrized magnetic models for a large sample of new Ap star magnetic field measurements by Mathys and his collaborators, and to see what information about Ap magnetic fields is hidden in these data. And of course there are other projects waiting for a little time....
I am fortunate to be associated with (a perceptive person might even say "sustained by") an excellent research group, including one-time UWO undergraduate, now UWO Assistant Professor Aaron Sigut; and undergrads Anna Townshend and Jessie Silaj. I have some great international collaborations with, for example, former Ph D student, now Assistant Professor at the Royal Military College, Gregg Wade, Stefano Bagnulo at the European Southern Observatory, Jean-Francois Donati at l'Observatoire Midi-Pyrenees in Toulouse, and Gautier Mathys at the European Southern Observatory. And of course I depend heavily on excellent technical support from computer specialist Henry Leparskas and technician and instrument designer Mike Debruyne.
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