Our solar system has 8 planets, but there are nearly 2000 exoplanets (so called because they are outside our solar system). These exoplanets help provide answers to scientists working on a wide range of issues, including whether life exists on other planets. However, they are difficult to study because, since they orbit very close to their star, they are generally masked by the star’s light. In 1997, Professor Maria Teresa Ruiz discovered an unusual celestial body, previously theorized but never observed: the first free-floating brown dwarf.
Bigger than giant planets but fainter than stars, brown dwarfs are thought of as being failed stars or expanded planets. They are quite similar to exoplanets, and easier to observe. By studying brown dwarfs, astrophysicists can thus better understand the characteristics of exoplanets, how they evolve over time and the conditions necessary for the development of life on planets other than Earth. In other words, brown dwarfs are excellent exoplanet laboratories.
Head of the Department of Astronomy at the University of Chile in Santiago, Prof. Ruiz named her discovery Kelu 1. Kelu means “red” in the language of the Chilean Mapuche Indians and Kelu-1 is said to be free-floating because it
wanders through space without being attached to any stellar system.
Prof. Ruiz also studies another type of faint star, the white dwarfs, which are the solid remains of dead stars. More than 97% of the stars in our galaxy become white dwarfs at the end of their lives. By studying the coldest ones, Prof. Ruiz and her colleagues have succeeded in calculating that the age of the Milky Way’s Disk is about 8 billion years old. This result did not come easy: the researchers spent hundreds of long, cold nights on a remote desert observatory and two decades consulting their best data. This goldmine of information has been published in
dozens of scientific articles and represents the most up-to-date research on white dwarfs.
Prof. Ruiz’s career reads as a series of 40-year firsts: She is first woman to have taken a degree in astronomy at the University of Chile; she was the first female scientist to receive a PhD in astrophysics at Princeton University; and the first woman to receive her country’s National Award for Exact Sciences. Now 70, she has also just been named the first woman president of the Chilean Academy of Sciences and was recognized by the American Astronomical Society (AAS) in 2004, when she became an honorary member. Outside the Americas, she is well known for her role in setting up the muchcoveted international giant radiotelescope ALMA (Atacama Large Millimeter/submillimeter Array). The telescope, built in partnership with ESO (European Southern Observatory), is installed in the Atacama Desert in the north of Chile in a high-up (5000 meters above sealevel) region where there is little light pollution. The atmosphere there is also very dry, making it ideal for sub-millimeter astronomy, since radiation at these wavelengths is absorbed by water vapor in the atmosphere.