(M=20 Suns, R=1,000 Suns, L=135,000 Suns, T=3,500 K, d= 600 l.y., Age = 8.5 million years)

PROPERTIES OF STARS


Properties of Typical Main Sequence Stars

  • M* = 0.08 to ~50-100 MSun
  • R* = 0.1 to ~103 RSun
  • T* = 2,500 K to 50,000-100,000 K*
  • L* = 10-4 to 105 LSun

Properties of the Sun (Solar Units)

  • MSun = 2.0x1030 kg
  • RSun = 7.0x105 km
  • TSun = 5,800 K
  • LSun = 3.9x1023 kW

Properties of the Earth

  • ME = 3.0x10-6 MSun
  • RE = 9.2x10-3 RSun
  • TE = 283-288 K ~ 50-60 Farenheit
  • LE ~ 1.8x1014 kW

Although, at first glance the range in properties seems large, a significant point is that the range is as small as it is. Clumps of matter in the Universe range from things as smaller or smaller than nuclei of atoms, masses on the order of 10-27 kgram and diameters on the order of 10-15 meter, to structures on the scale of the Universe itself which is larger than tens of billions of light years across.




Temperature Scales

The Kelvin temperature scale starts at Absolute Zero (-273.15 Centigrade [C]); Centigrade starts at the freezing point of water.

    Kelvin: T(K) = T(C) + 273.15

    Centigrade: T(C) = (5/9)*[T(F)-32 F] -- F stands for Farenheit

At very high temperatures, there is little difference between Kelvin and Centrigrade temperatures. For example, the average surface temperature of the Sun is 5,800 K which is 5,527 C. The two temperatures are nearly the same. Farenheit, on the other hand, is much different. The Sun at 5,800 K is around 10,000 F!

T(K) = 5,800 Kelvin = 1.8 x 5,800 = 10,440 above absolute zero ===> 10,440 - 460 ~ 9,800 F.