SCI 102 Lecture Notes - Lecture 7: Horse Length, Maarten Schmidt
13 Apr 2016
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Document Summary
Spirals: central bulge is reddish-orange from old stars there, arms are blue from the presence of hot young stars. Forming from the gas and dust in the arms. Irregulars: contain largest amounts of dust/gas, blue-est galaxies known, support the most active star birth. Luminosity = l = total energy emitted each second. R is radius of object in meters. If the luminosity, l, of a galaxy is n times the luminosity of the sun, nlo, then, a rough estimate of its mass is n times of the sun, nmo. The milky way is estimated to have luminosity of lmw ~ 1 x 1011lo. Mmw ~ (1 x 1011) (1,99 x 1030kg) Galaxy masses range from ~ 1 x 105 mo to ~ 1 x 1013 mo. Our galaxy, the milky way, has a mass of ~ 5. 8 x 1011 mo. Spirals form/contract slowly and have gas/dust to support ongoing star birth.
