Efrho¶

class sbpy.activity.dust.Efrho(value, unit=None, dtype=None, copy=True)[source]¶

Bases: sbpy.activity.dust.DustComaQuantity

Coma dust quantity for thermal emission.

Efrho behave like Quantity objects with units of length.

Parameters

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.

Notes

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.

References

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

Examples

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

Methods Summary

`from_fluxd`(wfb, fluxd, aper, eph, **kwargs)	Initialize from spectral flux density.
`to_fluxd`(wfb, aper, eph[, unit, Tscale, T, B])	Express as spectral flux density in an observation.

Methods Documentation

classmethod from_fluxd(wfb, fluxd, aper, eph, **kwargs)[source]¶

Initialize from spectral flux density.

Parameters

wfbQuantity, SpectralElement, list: Wavelengths, frequencies, bandpass, or list of bandpasses of the observation. Bandpasses require synphot.
fluxdQuantity: Flux density per unit wavelength or frequency.
aperQuantity or Aperture: Aperture of the observation as a circular radius (length or angular units), or as an Aperture.
eph: dictionary-like, `~sbpy.data.Ephem`: Ephemerides of the comet. Required fields: ‘rh’, ‘delta’. Optional: ‘phase’.
**kwargs: Keyword arguments for to_fluxd.

to_fluxd(wfb, aper, eph, unit=None, Tscale=1.1, T=None, B=None)[source]¶

Express as spectral flux density in an observation.

Assumes the small angle approximation.

Parameters

wfbQuantity, SpectralElement, list: Wavelengths, frequencies, bandpass, or list of bandpasses of the observation. Bandpasses require synphot. Ignored if S is provided.
aper: `~astropy.units.Quantity`, `~sbpy.activity.Aperture`: Aperture of the observation as a circular radius (length or angular units), or as an sbpy Aperture.
eph: dictionary-like, `~sbpy.data.Ephem`: Ephemerides of the comet. Required fields: ‘rh’, ‘delta’. Optional: ‘phase’.
unitUnit, string, optional: The flux density unit for the output.
Tscalefloat, optional: Scale factor for blackbody in LTE with sunlight. Ignored if T or B is provided.
TQuantity, optional: Blackbody temperature. Ignored if B is provided.
BQuantity, optional: Observed spectral flux density from a blackbody sphere, i.e., pi * Planck function. Overrides T and Tscale.

Returns

fluxdQuantity: Spectral flux density.

Examples

>>> from sbpy.activity import Efrho
>>> import astropy.units as u
>>> efrho = Efrho(120.0, 'cm')
>>> freq = 15.8 * u.um
>>> aper = 11.1 * u.arcsec
>>> eph = {'rh': 4.42 * u.au, 'delta': 4.01 * u.au}
>>> fluxd = efrho.to_fluxd(freq, aper, eph=eph, unit='Jy')
>>> print(fluxd)                           
0.006519545281786034 Jy

Navigation

Efrho¶