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	Beyond the Solar System > Stars Image Gallery Battle of the Clusters  Catty Star  Holding Together  More images » Resources Brightest stars Extrasolar planets Latest news about exoplanets FAQs about Stars and Nebulae Astronomy Gift Shop 2009 Sky Almanac McDonald Observatory logo cap The Texas Connection Measuring the Stars Ongoing research by Texas astronomers and others helps us understand the age, composition, and weight of stars. Age Gas surrounds a young white dwarf. Texas astronomers are part of a worldwide team that is using the oldest stars in the Milky Way to measure the galaxy's age. The stars are called white dwarfs. They are the hot, dense cores of once-normal stars that have cast their outer layers into space. Astronomers can accurately determine a white dwarf's age by measuring its brightness and temperature. Texas astronomers Don Winget, Ted von Hippel, and Mukremin Kilic are looking for the coldest white dwarfs in the Milky Way's broad disk of stars. By understanding the ages of its oldest stars, astronomers can more accurately determine the age of the disk and other regions of the Milky Way. Composition Part of Procyon's spectrum. The death of one generation of stars has an impact on the generations that follow. Texas researcher Carlos Allende Prieto is learning more about this process by studying many stars, including Procyon, one of the brightest in the night sky. Procyon's chemistry is similar to that of the Sun and most other stars in our region of the galaxy, with moderate amounts of oxygen, carbon, iron, and other heavy elements. These elements tell us that the star is of a fairly recent generation. The first stars were made almost entirely of hydrogen and helium, which were created in the Big Bang. These early stars forged heavier elements in their cores. When the stars died, they expelled some of these elements into space. Each generation of stars has more of these heavy elements than the one before it. When Procyon and similar stars die, they, too will cast many of these elements into space, where they can enrich future generations of stars. Weight Proxima Centauri, the star closest to our solar system, is a red dwarf. One of the most important properties of a star is its mass. It determines the star's temperature, how long it will live, and more. Fritz Benedict is working to refine a technique for determining the masses of red dwarfs, some of the smallest but most common stars in the galaxy. The technique is called the mass-luminosity relationship, and it allows astronomers to determine a star's mass by measuring its true brightness or luminosity. But measuring brightness requires exact knowledge of the star's distance. Benedict is combining several techniques to measure precise masses and distances of red dwarfs, which will help refine the mass-luminosity relationship for this class of stars. This document was last modified: October 19 2009.
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