Describe the two main affects of that friciton. Gas streams in the accretion disk move under the influence of gravity from the central object. Streams closer to the star move faster. This means that the streams are always slipping, against adjacent streams . This slippage results in friction which causes heat that makes light .
Friction also causes drag that makes the streams spiral inward toward the central object .
This is the process of accretion . Describe the observations and logic that leads to the conclusion that Type Ib and Type Ic supernovae result from core collapse of a massive star with a binary companion. Type Ib and Ic supernovae are observed to occur in the spiral arms of spiral galxies and do not occur in elliptical galaxies . This suggests that their progenitor stars are short lived and hence massive so the supernovae is likely to result from core collapse . The lack of hydrogen in their spectra means that the outer layers have been removed either by a strong stellar wind of by a binary companion.