POLI 1F90 Lecture Notes - Military Medal, Protostar, Reflection Nebula
31 Jan 2013
School
Department
Course
Professor
Document Summary
Star formation: to find out about the process of star formation one should look at the young stars. Mass luminosity relation for main sequence stars is l(luminosity)= m*3. 5 (mass of a star) lifetime of a star = amount of fuel/energy output. The youngest stars are located at the top left corner of the main sequence - they appear as bluish (high surface temp. ) and they have very high luminosities. The observations show that such stars are surrounded by gas and dust of interstellar material (ism) Gas: 74% by mass is hydrogen (h) 2% by mass is all the other elements. Dust: consists of core and mantle, 10-100nm across (1nm=10*-9 meters: core silicate material ices of water, ammonia and methane. When the clouds of interstellar material are observed in the visible part of the spectrum (wave lengths: 400 nm 700 nm), they are called nebulae. There are several types of nebulae: dark nebula.
