Uffe Gråe Jørgensen

Personal data:

     Name: Uffe Gråe Jørgensen
    Title: associate professor (Danish "lektor")

    Email: uffegj@nbi.dk
      Fax: +45 3532 5989
    Phone: +45 3532 5998
Secretary: +45 3532 5996

    The postal address of the institute is:
    Astronomical Observatory, Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen Ø, Denmark
    The building where the observatory is situated was originally financed by the 
    Rockefeller Foundation, and is therefore called the Rockefeller Complex ("Rockefeller Komplekset").
    You will get a map of the area with  "Rockefeller_Komplekset"  marked on the map by clicking here.
    My office is room 385, and you can find the position of my_office at the third floor of the building by clicking here.

Research:

(1) Extrasolar planets (exoplanets) Since 2002 I have been involved in the search for extrasolar planets by use of the microlensing technique, as part of the international team PLANET . Our most recent result is the discovery of the first Earth-like exoplanet ever seen. Although the planet is far from identical to the Earth (for one it is estimated to have a surface temperature of -200 Celcius degrees), it is Earth-like in the sense of having a mass (5.5 Earth-masses) and an orbit (2.6 AU) much more resembling the Earth than any exoplanets ever observed before, and by being the only of the known exoplanets which might have formed and eveloved in the same way as the terrestrial planets in our own solar system (see below). The printed version of the paper describing the first results of the discovery, can be forund in Nature, vol.439, p.437-440. If your login allows it, the paper can be downloaded from Nature's homepage (otherwise use the ads-link above to retrieve a re-print) together with Nature's comments to the discovery on page 400-401 in the same issue of the journal. A short press-release animation made by ESO can be viewed here.
Other recent papers related to the work on microlensing by our team, include 1 , 2 , 3 , 4 , 5 , 6 , 7 .

(2) Late stages of stellar evolution. This has included research about
(1)red giant stars, (e.g., chemical abundances in Galactic halo stars , the formation of poly aromatic hydrocarbon clusters, PAH , and effects of mass loss on stellar evolution),
(2) white dwarfs ,
(3) globular clusters and the age of the universe, (e.g., results , and the method ),
(4) stellar populations in other galaxies (e.g., the Fornax Dwarf galaxy , population synthesis by use of the Ca IR triplet , and the UV radiation in metal-rich galaxies ) and
(5) other aspects of the final stages of evolution of normal stars (e.g., the final evolution of the Sun )

(3) The atmospheres of late-type stars, planets, brown dwarfs, and other plasmas where molecular absorption plays a role. Most of the work I have done in the field of modeling and simulations of cool gasses, is done with the MARCS stellar atmospheric code. A review of the atmospheric modelling was given in late 1994 in Astr.Astrophys.Rev.. My major contributions to the development of the atmospheric modelling technique includes
(1) effects and compuitations in spherical geometry ,
(2) the sampling technique ( 1992 , 1998 ),
(3) the role of molecular opacities ,
(4) the role of hydrodynamics (e.g., A&A 1999 and A&A 1998 ),
(5) testing the models against spectral observations from space (e.g., our ISO_spectra of carbon stars), and from the ground (e.g., complete AGB carbon star spectra from 5000 AA to 2.5 mu_m, and high-resolution SiO_spectra of M-type giants).

A major obstacle for progress in this field has during a few decades been the lack of input data for the modelling. A substantial part of my effort in the field has therefore been to perform quantum mechanical computations of molecular line lists and other crucial input data. A review of the data base that has been one outcome of this work was described in a review paper at IAU Symposium 178. A describtion of the quantum mechanical methods we have been using was given in our first papers on the absorption coefficient of HCN and C3 . A recent paper in the work of constructing a molecular opacity data base is the calculation of the absorption coefficient for water . See also the separate description of the SCAN molecular data base below.

(4) The formation and evolution of the solar system. My contribution to this field has mainly been concerning the origin of the material which the solar system is made of. We have extracted extrasolar diamonds and silicon_carbide grains from carbonaceous chondrite meteorites and measured their optical properties. By including these data in atmospheric modelling it is in principle possible to trace the stellar origin of the material that became the solar system. My original ideas about origin of the meteoritic extrasolar diamond (and SiC) dust in carbon stars were presented in paper in Nature in 1988. A recent description of our ideas about the stellar-meteoritic connection was presented at IAU Symposium 177.
I have also contributed to the solar system research with preditions and speculations about what will happen to the Sun and the Earth during the final phases of the evolution of the Sun (a short proceeding and a longer A&A paper, emphasizing different aspects), and with aspecta of the formation of the solar nebula and the formation of the Earth and its oceans (work in preparation).

The SCAN molecular data base:

Teaching:

Courses I am teaching:

Thesis supervision:

Suggestions for B-colloquia (hovedfags colloquia):

Suggestions for Thesis projects (specialer):

Popularization:

I regularly publish popular articles in various journals, recently:
Naturens Verden about Tycho Brahe (NV, vol.84, nr.10, p26-31)
Naturens Verden about the origin or the Earth's oceans (NV, vol.85, nr.2, p2-13),
Aktuel Astronomi about exoplanets (AA, 2004 nr 2, p.16-19),
Kvant about the formation of solar systems (vol.15 nr.3, 2004, p.8-14),
Kvant about the Deep Impact collision with Comet Tempel (vol.16 nr.3, 2005, p.11,12,36),
Universitetets Almanak 2006 about exoplanets (2006).

ESO users committee: