A cometary nucleus model taking into account all phase changes of water ice: amorphous, crystalline, and clathrate

U. Marboeuf; B. Schmitt; J.-M. Petit; O. Mousis; N. Fray

doi:10.1051/0004-6361/201118176

Home

All issues

Volume 542 (June 2012)

A&A, 542 (2012) A82

Full HTML

Free Access

Table 3

Parameters for clathrate formation/dissociation.

Symbol	Name	Unity	Value

n _hyd	Hydrate number		6^α
	Bulk density of water structure of clathrate	kg m^-3	790
k^cl	Heat conductivity of clathrate	W m^-1 K^-1
	Valid temperature range for values
	T ≤ 80 K		5.47954 × 10^-2 T − 3.13102 × 10^-3 T²
			+ 9.40412 × 10^-5 T³ − 1.29299 × 10^-6T⁴
			+ 6.38159 × 10^-9T⁵^β
	T ≥ 80 K		2.1 × 10^-4 T + 0.43^χ
H	Absolute enthalpy of dissociation of guest trapped in clathrate	J mol^-1
	CO		15 720^δ
	CO₂		21 327^δ
	CH₄		18 130^ε
	H₂S		25 404^δ
	Nominal kinetics constant of formation of clathrate	mol m^-2 Pa^-1 s^-1	3 × 10^-13^φ
	Nominal kinetics constant of dissociation of clathrate	mol m^-2 Pa^-1 s^-1	^φ

Notes.

^α

Sloan (1998); Sun & Mohanty (2006);

^β

data fit of Krivchikov et al. (2005a,b, 2008);

^χ

Krivchikov et al. (2005a,b);

^δ

provided by the Clausius-Clapeyron equation from data given by references in Table 2;

^ε

Handa (1986b);

^φ

Englezos et al. (1987); Schmitt (1986).

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.