In the Maternity Room of the Stars
The astrophysicist Bérengère Parise
Dieser Artikel in Deutsch
Bérengère Parise (Fotos: Uschi Heidel).  |
Christmas 1988: ten year-old Bérengère Parise excitedly opens her present, a book about stars. The gift the father had lovingly put under the Christmas Tree has undreamt of consequences for the daughter. The strange worlds so far from our earth hold a fascination for the girl that is so irresistible that it has not diminished to this day. As the French woman herself says, she still sees the twinkling lights on the dark firmament through "the eyes of a child". However nowadays, as an astrophysicist, she tries to get behind the secrets of the stars. She would like to learn more about their birth. And this is the end to which she is utilising her Humboldt Research Fellowship at the renowned Max Planck Institute for Radio Astronomy in Bonn.
Many people imagine it's romantic to investigate the universe: eager scientists staring full of wonder through huge telescopes and observing the beauty of the cosmos. Bérengère Parise had realised that the reality at observatories was rather different, but she was disappointed none the less when she discovered on her first visit that it was not she who looked through the telescope and compiled the data, but the computer. "Actually to put your eye to the lens - that's something really special," the 28 yearold comments. As a child she had gazed at the enormous planet Jupiter through her younger sister's telescope.
The inner life of evolving stars
What the astrophysicist sees when she evaluates the computer data leaves the layperson underwhelmed, but for the enthusiastic scientist it is thrilling: lines and more lines with different high peaks, similar to an ECG. But what this diagram shows is not the activity of the heart but the inner life of evolving stars. The lines reveal information about molecules involved in chemical reactions at the various stages of birth of these celestial bodies.
 |
The scientist from Toulouse is interested in the evolution of stars with little mass like the sun. The theory is that stars are born in very cold clouds of dust and gas. They cannot be recorded on the optical wavelength but only on the millimetre and submillimetre scale. The material in these cold clouds condenses into prestellar cores. What causes the "contractions" is as yet unclear. The pre-stellar cores composed of dust and gas are the preliminary stages of a star. At the next stage, the cores begin to collapse and fall in on themselves, attracted by the force of gravity. From this centre a protostar develops. It is still too cold to burn hydrogen and be a proper star. But the continuous growth of mass caused by the pull of gravity gives it the energy necessary to shine and warm its atmosphere. In this way, a core is formed with temperatures of around minus 100 degrees Celsius. Scientists have discovered complex molecules in these gaseous preliminary stages of stars. And this is precisely where Bérengère Parise sets in. She wants to know how these syntheses come about.
Yesterday was 100,000 years ago
The birth of a star takes a long time - more than 100,000 years. For Bérengère Parise that's just "yesterday". So, even during her studies in Paris she decided that she didn't want to research into the big bang and the origins of the cosmos. "That's just too long ago for me!" Now she's investigating the chemistry at the stages of birth: dust and gas clouds, prestellar cores, protostar. In the pre-stellar cores it is so cold that atoms and molecules freeze to the surface of dust particles, react with them chemically and may form an ice layer. When subsequently, the protostar gradually heats up its atmosphere the layer of ice melts and releases atoms and molecules into the gaseous atmosphere.
In order to find and analyse molecules the Humboldt fellow first has to aim high: at 5,100 metres where the atmosphere is clear and dry and where is no water vapour to hamper observations. On the Chajnantor Plateau in Chile's Atacama Desert the telescope belonging to the Atacama Pathfinder Experiment (APEX) has been in operation for a good year or so - run by the Max Planck Institute for Radio Astronomy together with the European Southern Observatory (ESO) and the Onsala Space Observatory (OSO). "What strikes you most about this submillimetre telescope, which is the largest there for investigating the southern skies, is its gigantic antenna," Bérengère Parise notes. She was one of the first to be able to use APEX for her research. By recording on the sub-millimetre wavelength scale the scientists are opening a window, making it possible to get an unclouded view of some of the most interesting objects in the universe, including the maternity rooms of the stars.
Molecules present themselves
"Through the APEX telescope I can observe and record the rotational spectrum of the individual molecules in the gaseous stages of star evolution," the scientist explains and points to the ECGlike diagrams. "Every molecule presents itself as a different pattern." What the respective line looks like, with high peaks in the upper range, for example, depends on the temperatures and density of the gaseous atmosphere. The speed of the gas can also be measured in this way. "Observations of this kind are very significant", the researcher emphasises.
Bérengère Parise is concentrating on Deuterium, a hydrogen isotope occurring in small quantities in space. She is investigating the various chemical compounds Deuterium forms during the birth of stars. In the process she has discovered unexpected compounds which uncover new knowledge about the procedures.
Like many scientists, the astrophysicist is a modern nomad. "I'm only at the institute for a few weeks and otherwise always at conferences and, of course, observatories. Sometimes I wonder whether I shouldn't swap my flat for a hotel room, I'm there so seldom", the French woman comments. She has spent much and many of the last years working in international research teams in many countries. When she's not "looking at" the universe in Chile, she works at the IRAM telescope in the Spanish Sierra Nevada. She has followed the birth of stars on Hawaii, too, where the conditions are ideal. Bérengère Parise gets around the world a lot, loves travelling but also coming home. In the long run, the scientist would like to have a firm base in Europe, perhaps a somewhat quieter life, and be near her family and friends.
| 
