Stellar X-ray Sources in the Magellanic Clouds

Cowley 9417013距离银河系最近的两个星系是被称为大麦哲伦云和小麦哲伦云的小的不规则星系。 与我们自己的银河系不同，它们几乎不包含星际尘埃，使其中的恒星变暗。 相比之下，银河系的大部分区域被厚厚的星际尘埃带所掩盖，这些尘埃带沿着银河系的平面，阻止了对银河系后面恒星的观测。因此，麦哲伦云是研究各类恒星整体性质的理想实验室。 它们都包含许多与高度演化的双星系统有关的X射线源。 对这些天体的研究使我们能够了解接近演化末期的恒星的性质。 这些都是不寻常的天体，如白色矮星、中子星和黑洞。 该项目的目标是研究麦哲伦星云中的X射线源，以更多地了解这些恒星演化的最终阶段。 该项目将把ROSAT X射线卫星获得的这些恒星的准确位置与这些恒星的光学光度测定和光谱学相结合，以测量它们的质量、大小、温度和其他物理特性。 只有在这些罕见的双星系统中，我们才有机会直接研究简并恒星的性质，并了解它们如何与它们相互环绕的伴星相互作用。 ***

Cowley 9417013 The two nearest galaxies to the Milky Way are the small, irregular galaxies known as the Large and Small Magellanic clouds. Unlike our own Galaxy, they contain little interstellar dust to dim the stars within them. By contrast much of the Milky Way is hidden from observation by thick bands of interstellar dust which lie along the plane of the Galaxy preventing observation of stars behind it. Thus, the Magellanic Clouds are ideal laboratories in which to study the overall properties of various classes of stars. Both of them contain numerous X-ray sources which are associated with highly evolved binary systems. Study of these objects allows us to learn about the properties of stars which are nearing the end of their evolution. These are unusual objects such as white dwarfs, neutron stars, and black holes. The goal of this project is to study the X-ray sources in the Magellanic clouds to learn more about these end-stages of stellar evolution. This project will combine the accurate positions for these stars obtained with the ROSAT X-ray satellite with optical photometry and spectroscopy of these same stars to measure their masses, sizes, temperatures, and other physical properties. It is only in these rare binary systems that we have the opportunity to investigate directly the properties of degenerate stars and learn how they interact with their mutually orbiting companion stars. ***