João Lin Yun

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As a member of the Center for Astronomy & Astrophysics, and researcher of the Observatório Astronómico de Lisboa, and as staff Professor at the Physics Department of the Faculdade de Ciências of the University of Lisbon, I teach courses of the Physics BS degree and of the Master's degree in Astronomy and Astrophysics.

I can be reached at my office's address:

Observatório Astronómico de Lisboa
Tapada da Ajuda
1349-018 Lisboa, PORTUGAL

Telefone: 21 361 6739
FAX: 21 361 6752

or through E-mail: Joao.Yun "at" oal.ul.pt

The line of research that I have been exploring with BSc., MSc., and PhD. students, is focused on the study of the physical conditions and stellar content of molecular clouds. We use techniques of optical, infrared and radio astronomy in the following lines of research:

Line 1: Young stellar objects embedded in molecular clouds.

Using near-infrared array images, we explore the interior of dark molecular clouds. We have discovered stars in the process of formation still embedded in their parent molecular cloud. Many of these stars are surrounded by circumstellar disks revealed by color excesses in the infrared and by spectral energy distributions distinct from those of a blackbody.

Similarly, objects in later stages of evolution, closer to the main-sequence, are optically visible. Spectra of these objects allow us to confirm their T Tauri star character. CCD images of these regions were used to search for the presence of HH objects and optical jets in the vicinity of the young stars.

Line 2: Structure and physical conditions in molecular clouds.

We use techniques in Radio-Astronomy to map molecular clouds in the line transitions of a few molecular species present in the Interstellar Medium. This maps allow us to study the distribution of temperature and density in this clouds, as well as the velocity fields, providing information to analyze their stability and potential to form stars.