John D. Hadjidemetriou was born in Thessaloniki in 1937. He got his B.Sc. in Mathematics from the University of Thessaloniki in 1959 and his Ph.D. in Physics and Astronomy from the University of Manchester in 1965, under the guidance of Prof. Z. Kopal. In 1970, he was elected full Professor of Theoretical Mechanics at the Physics Department of the University of Thessaloniki, at the age of 33. He continuously served the department over a period of 42 years.
John’s Ph.D. Thesis “The two body problem with variable mass” (and his first paper in Icarus 2, 440, 1963), has been recognized as a fundamental contribution in the field and is still cited in the literature. Since then he continued working on Celestial Mechanics, in particular on families of resonant periodic orbits in the restricted and general three-body problems and on the stability of planetary, asteroid and satellite motion. He always stressed that “periodicorbits consist the backbone of the topology of phase space”. John also became famous for his method of constructing a symplectic map that preserves the location and stability of periodic orbits in resonances, which became known as “Hadjidemetriou’s map”.
In later years he worked on the interpretation of the phenomenon known as stable chaos and on the dynamics and stability of exo-planetary systems. He associated the resonant planetary dynamics with families of periodic orbits and he computed these families for various cases. He also showed that the introduction of dissipative forces makes the periodic orbits “attractors” and a planetary system migrates along the families, verifying, in such a way, the work on planetary migration published previously by other researchers. In this framework he showed the possibility of the transition from a 1/1 resonant planetary motion to a satellite motion. The last paper he co-authored, entitled “Multiplanet destabilization and escape in post-main- sequence systems”, appeared recently in MNRAS (430, 3383, 2013) and was based on the theory he developed in his first paper.
John played a key role in the development of Celestial Mechanics in Greece. He supervised 7 Ph.D. Theses in this field and acted as coordinator or principal investigator in three EU-funded research projects. He retired in 2005 and, since then, he remained active both in teaching and in research, as Professor Emeritus of the University of Thessaloniki. His numerous students organized a Conference in his honor in the summer of 2008, in Litohoro, Greece, which was attended by about 70 participants from 16 countries.
John was a corresponding member of the Academy of Athens. He was also an elected member of Commission’s 7 SOC from 1979 to1991 and served as President of the Commission for the 2000–2003 term. He was a member of the Celestial Mechanics Institute and Associate Editor of the field’s leading journal, Celestial Mechanics and Dynamical Astron- omy, for twenty years. He was a founding member of the European Astronomical Society and the first vice-president of the Hellenic Astronomical Societiy.
John really excelled in teaching, not only within his duties in the University of Thessaloniki but in international schools as well. He was an active member of the Cortina and Ramsau/Bad Hofgastein meetings as well as of the Greek Non-linear Dynamics annual schools. He wrote a two-volume book on Theoretical Mechanics, in Greek, which is still adopted by many Greek Universities.
John Hadjidemetriou passed away peacefully on Thursday, March 21, 2013, in Thessaloniki, Greece.
Professor (retired), Department of Physics, University of Crete, Greece. Born in Mendenitsa Lokris, Greece in 1947. He
received the B.Sc. in Physics from the Aristotle University
of Thessaloniki (1970) and his Ph.D. from the University of
Saskatchewan in Canada (1978). He is involved with the
University of Crete since its beginning in 1978. He worked
for two years (1979-81) as a Postdoctoral fellow in the
Institute of Physics, University of Oslo, Norway, and as a
reasearch associate (1984-85) in the Institute of Space and
Atmospheric Studies, University of Saskatchewn, Canada.
During the 20-year period from 1984 to 2004, he worked
for a total of 3 years as a Research Scientist in the Max-
Planck Institut fuer Aeronomie, Germany, for several months in the Universite de Paris VI (Pierre and Marie Curie), and for 6 months as a visiting professor in the Universite de Rennes I, France. Also he spent in 2005 four months as a visiting Professor in the Solar-Terrestrial Environment Laboratory, Nagoya University, Japan. In the Physics Department, University of Crete, he is responsible for the Laboratory of Ionospheric Physics. His scientific interests are in Upper Atmospheric and Ionospheric Physics: Ionospheric coherent and incoherent radio wave scattering; Ionospheric Plasma irregularities and instabilities; midlatitude sporadic E-layers, formation, plasma instabilities and electrodynamics; Midlatitude E/F region electrodynamic coupling; Coupling of Mesosphere Lower Thermosphere (MLT) dynamics (winds, gravity, tidal and planetary waves) with sporadic E layer plasma; VLF propagation and ionospheric modification during thunderstorms and Transient Luminous Events (sprites and elves). Geophysical data analysis techniques. Radar coherent backscatter experimentation. Digital Ionosonde, Geomagnetometric and VLF subionospheric measurements. Also he has done applied research on wind potential and energy Studies. He is author of more than 90 refereed papers, and has about 20 invited talks and 140 presentations in international conferences. He received The Max-Planck Institute Golden Pin award for Research in 1999. He served as a guest editor of the Journal of Atmospheric and Solar-Terrestrial Physics and of Annales Geophsicae. He served as Associate Editor of the Radio Science Bulletin, and since 2006 he serves as associate Editor of the Journal of Geophysical Research - Space Physics. He is a member of the American Geophysical Union and the European Geophysical Union.
Emilios T. Harlaftis (Greek: Αιμίλιος Χαρλαύτης; 29 March 1965, Kiato – 13 February 2005 Menalo) was an astrophysicist.
Harlaftis obtained an undergraduate degree in physics at the University of Athens in 1987, and a Ph.D. degree at the University of Oxford in 1991. From 1991 to 1995 he worked as a support astronomer at the Isaac Newton Group of telescopes of the Royal Greenwich Observatory, placed at the Observatory of Roque de los Muchachos (owned by the Instituto de Astrofisica de Canarias at the island of La Palma. He then worked as a research assistant (1995–1997) at the University of St. Andrews and as a research fellow (1997–1998) at the Institute of Astronomy and Astrophysics of the National Observatory of Athens. After a series of posts as a visiting scientist at the University of Sheffield, and the NASA Goddard Space Flight Center (1999), and two years as a temporary Reader at the School of Physics and Astronomy at the University of St. Andrews (2001–2002) he returned to Greece where he was a tenured researcher at the Institute of Space Applications and Remote Sensing of the National Observatory of Athens. He acted as a principal investigator for the Aristarchos 2.3 m Telescope located at the Chelmos mountain, which colleagues suggested to name after him, following his death in an avalanche accident.