Symbol
Meaning
Typical unit
Introducing
equation
Q col
Specific impact energy of a collision
7.1
Q d_direct
Production rate of dust particles removed
from activity source and escaping
[molecule s
À1
],
[kg s
À1
]
4.126
Q d_fallback
Number of particles removed from activity
source and falling back
[molecule s
À1
],
[kg s
À1
]
4.127
Q d_outgassed
Final refractory mass loss from the comet
[molecule s
À1
],
[kg s
À1
]
4.125
Q damp
Quality factor of the material
Unitless
2.54
q f
Gas flux through a porous layer or through a
tube
[m
À2 s
À1
]
3.104
Q g,d
Gas (dust) production rate
[molecule s
À1
],
[kg s
À1
]
1.27, 2.112,
3.10, 4.1
Q g_direct
Direct gas production through activity
[molecule s
À1
],
[kg s
À1
]
4.125
Q g_extended
Gas production caused by volatiles being
lost by escaping particles
[molecule s
À1
],
[kg s
À1
]
4.125
Q g_indirect
Gas lost from the comet through outgassing
of dust that falls back
[molecule s
À1
],
[kg s
À1
]
4.125
Q gp
Parent production at source in the Haser
model
[molecule s
À1
]
3.107
q p, q d
Total number of parent (daughter) molecules
crossing a spherical surface from a point
source in the Haser model
[molecule s
À1
]
3.107,
3.112
Q pr
Radiation pressure efficiency factor
Unitless
4.68
Q s
Source term in the mass conservation equation for fluids
3.50
Q sca, Q ext, Q abs Scattering, extinction, absorption
efficiencies
Unitless
4.33
Q T
Total production rate from a defined source [molecule s
À1
]
3.97
r
Cometocentric distance
[m]
3.1
r 0
Heliocentric distance inside which bulk of
solar insolation goes into subliming ice at
the surface of the nucleus
[AU]
1.22
r a, r p
Apoapsis (periapsis) distance
[AU]
1.4
R BB
Radiant exitance of a black body
[W m
À2
]
2.23
r c
Gyroradius
[m]
5.18
R c
Characteristic radius of a particle
[m]
4.40
r ce
Radius of the electron collisionopause
[m]
5.34
R CO2
Ratio of different isotopic compositions of
CO 2
Unitless
3.124
r ej
Distance from rotation axis in normal
direction
[m]
2.34
r eq
Radius of the outer edge of the equlibrium
regime in the coma
[m]
Fig. 3.2
(continued)
xxx
Symbols Used
Meaning
Typical unit
Introducing
equation
Q col
Specific impact energy of a collision
7.1
Q d_direct
Production rate of dust particles removed
from activity source and escaping
[molecule s
À1
],
[kg s
À1
]
4.126
Q d_fallback
Number of particles removed from activity
source and falling back
[molecule s
À1
],
[kg s
À1
]
4.127
Q d_outgassed
Final refractory mass loss from the comet
[molecule s
À1
],
[kg s
À1
]
4.125
Q damp
Quality factor of the material
Unitless
2.54
q f
Gas flux through a porous layer or through a
tube
[m
À2 s
À1
]
3.104
Q g,d
Gas (dust) production rate
[molecule s
À1
],
[kg s
À1
]
1.27, 2.112,
3.10, 4.1
Q g_direct
Direct gas production through activity
[molecule s
À1
],
[kg s
À1
]
4.125
Q g_extended
Gas production caused by volatiles being
lost by escaping particles
[molecule s
À1
],
[kg s
À1
]
4.125
Q g_indirect
Gas lost from the comet through outgassing
of dust that falls back
[molecule s
À1
],
[kg s
À1
]
4.125
Q gp
Parent production at source in the Haser
model
[molecule s
À1
]
3.107
q p, q d
Total number of parent (daughter) molecules
crossing a spherical surface from a point
source in the Haser model
[molecule s
À1
]
3.107,
3.112
Q pr
Radiation pressure efficiency factor
Unitless
4.68
Q s
Source term in the mass conservation equation for fluids
3.50
Q sca, Q ext, Q abs Scattering, extinction, absorption
efficiencies
Unitless
4.33
Q T
Total production rate from a defined source [molecule s
À1
]
3.97
r
Cometocentric distance
[m]
3.1
r 0
Heliocentric distance inside which bulk of
solar insolation goes into subliming ice at
the surface of the nucleus
[AU]
1.22
r a, r p
Apoapsis (periapsis) distance
[AU]
1.4
R BB
Radiant exitance of a black body
[W m
À2
]
2.23
r c
Gyroradius
[m]
5.18
R c
Characteristic radius of a particle
[m]
4.40
r ce
Radius of the electron collisionopause
[m]
5.34
R CO2
Ratio of different isotopic compositions of
CO 2
Unitless
3.124
r ej
Distance from rotation axis in normal
direction
[m]
2.34
r eq
Radius of the outer edge of the equlibrium
regime in the coma
[m]
Fig. 3.2
(continued)
xxx
Symbols Used