Universiteit Leiden

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Xander Tielens

Professor of Physics and chemistry of the interstellar medium

Prof.dr. A.G.G.M. Tielens
+31 71 527 8465

Xander Tielens is a Full Professor at Leiden University. His research involves Polycyclic Aromatic Hydrocarbons (PAH molecules). He was one of the first people to acknowledge the importance of these molecules in the universe. In 2012, Tielens was the most cited astronomer of The Netherlands and his work lies at the basis of current research.

More information about Xander Tielens

Xander Tielens obtained his PhD with his thesis “Physics and Chemistry of interstellar dust” from Leiden University in 1982. Afterwards he worked as researcher at the University of California and the Ames Research Center of NASA. In 1997 he was appointed to Professor at the University of Groningen and he started working as researcher at SRON as well. Since 2009, Tielens is a Full Professor of Physics and Chemistry of the Interstellar Medium at Leiden University.

Tielens’ research focuses mainly on the interstellar space and, in particular, on the Polycyclic Aromatic Hydrocarbons (PAH molecules) that are found in this space. His research made a significant contribution to the field of gas that is present in the photo-dissociation regions, interstellar dust and interstellar ice.

Tielens is also involved in the development of several satellites and telescopes including the SOFIA telescope and the European Herschel satellite.

STRW page

Professor of Physics and chemistry of the interstellar medium

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Work address

Huygens Laboratory
Niels Bohrweg 2
2333 CA Leiden
Room number 528



  • Elsevier: Molecular Astrophysics Editor in Chief
  • Astrophysics space science Associate editor