class sbpy.activity.Efrho[source]

Bases: sbpy.activity.dust.DustComaQuantity

Coma dust quantity for thermal emission.

Efrho behave like Quantity objects with units of length.

valuenumber, Quantity

The value(s).

unitstr, Unit, optional

The unit of the input value. Strings must be parseable by units package.

dtypedtype, optional

See Quantity.

copybool, optional

See Quantity.


εfρ is the product of dust emissivity, dust filling factor, and circular aperture radius. It is nominally a constant for a steady-state coma in free expansion, and is the thermal emission equivalent for the Afρ quantity. See Kelley et al. (2013) for details.


A’Hearn et al. 1984, AJ 89, 579-591. Kelley et al. 2013, Icarus 225, 475-494.


>>> from sbpy.activity import Efrho
>>> print(Efrho(1000, 'cm'))
1000.0 cm