PHYS 037 Lecture Notes - Lecture 9: Brown Dwarf, Dim Stars, Angular Momentum
4 Nov 2016
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Document Summary
Origins of stars in interstellar clouds: stars begin as molecular clouds. Clouds of cold gas and interstellar dust. They can be hundreds of light-years across. Can have 10,000 solar masses of cold gas and dust. Collapse heats the cloud"s center & gravitational energy turns into heat: the cloud collapses in. Its rotation makes it form a disk-shape: 1 million years later, the disk develops a hot, dense core. Protostar: dif cult to nd, hidden by gas and dust. Infrared telescopes can nd them: gravity in molecular clouds causes the cloud to contract until the central object. At the same time, gas pressure resists gravity gets hot enough for nuclear fusion. If gravity overcomes internal pressure, a star can be formed. How they form: forms easier if another force compresses the molecular gas cloud. Would compress both, increase the gas density within them: increases gravity in clouds, affects balance between gravity and pressure.
