Temperature dependence of specific heat capacity and its effect on asteroid thermal models

Temperature in Kelvin

cv = 625 J/kg/K from the relation Kpcv = K. Bennett and McSween

^-...^..^.,

c

-_u

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(ii

900

850

800

750

2. 
   SPECIFIC HEAT CAPACITY OF ORDINARY CHONDRITES
   

LL Chondrite

L Chondrite

(1996), like Miyamoto et al. (1981), used thermal conductivity, diffussivity, and density; but since the diffusivity is taken to be a function of temperature, it is not possible to arrive at a constant value of specific heat capacity for the entire temperature range. For the same set of model parameters, the difference in peak temperatures between various thermal models is considerable. For example, values of Cv = 1200 J/kg/K (Herndon and Herndon, 1977; Haack et al., 1990), 700 J/kg/K (Grimm and McSween, 1989), and 625 J/kg/K (Miyamoto et al., 1981) yield asteroidal peak tempera­ tures of 707, 1006, and 1090 K, a spread of 383 K. Figure 2a,c shows the strong dependence of thermal profiles as the specific heat

capacity is increased from 600 to 1200 J/kg/K, in increments of

I100

(..)

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c%650

600

300 ⁴⁰⁰ 500 ^{600 700 800 900 1000 1100}