"""
Utility functions for converting quantities.
"""
from typing import Optional, Tuple, Union
import numpy as np
from typeguard import typechecked
from species.core import constants
[docs]
@typechecked
def apparent_to_absolute(
app_mag: Union[
Tuple[float, Optional[float]], Tuple[np.ndarray, Optional[np.ndarray]]
],
distance: Union[
Tuple[float, Optional[float]], Tuple[np.ndarray, Optional[np.ndarray]]
],
) -> Union[Tuple[float, Optional[float]], Tuple[np.ndarray, Optional[np.ndarray]]]:
"""
Function for converting an apparent magnitude into an absolute
magnitude. The uncertainty on the distance is propagated into the
uncertainty on the absolute magnitude.
Parameters
----------
app_mag : tuple(float, float), tuple(np.ndarray, np.ndarray)
Apparent magnitude and uncertainty (mag). The returned error
on the absolute magnitude is set to None if the error on the
apparent magnitude is set to None, for example
``app_mag=(15., None)``.
distance : tuple(float, float), tuple(np.ndarray, np.ndarray)
Distance and uncertainty (pc). The error is not propagated
into the error on the absolute magnitude if set to None, for
example ``distance=(20., None)``.
Returns
-------
float, np.ndarray
Absolute magnitude (mag).
float, np.ndarray, None
Uncertainty (mag).
"""
abs_mag = app_mag[0] - 5.0 * np.log10(distance[0]) + 5.0
if app_mag[1] is not None and distance[1] is not None:
dist_err = distance[1] * (5.0 / (distance[0] * np.log(10.0)))
abs_err = np.sqrt(app_mag[1] ** 2 + dist_err**2)
elif app_mag[1] is not None and distance[1] is None:
abs_err = app_mag[1]
else:
abs_err = None
return abs_mag, abs_err
[docs]
@typechecked
def absolute_to_apparent(
abs_mag: Union[
Tuple[float, Optional[float]], Tuple[np.ndarray, Optional[np.ndarray]]
],
distance: Union[
Tuple[float, Optional[float]], Tuple[np.ndarray, Optional[np.ndarray]]
],
) -> Union[Tuple[float, Optional[float]], Tuple[np.ndarray, Optional[np.ndarray]]]:
"""
Function for converting an absolute magnitude
into an apparent magnitude.
Parameters
----------
abs_mag : tuple(float, float), tuple(np.ndarray, np.ndarray)
Tuple with the absolute magnitude and uncertainty (mag).
The uncertainty on the returned apparent magnitude is
simply adopted from the absolute magnitude. Providing the
uncertainty is optional and can be set to ``None``.
distance : tuple(float, float), tuple(np.ndarray, np.ndarray)
Tuple with the distance and uncertainty (pc). The uncertainty
is optional and can be set to ``None``. The distance
uncertainty is currently not used by this function but
included so it can be implemented at some point into the
error budget.
Returns
-------
float, np.ndarray
Apparent magnitude (mag).
float, np.ndarray, None
Uncertainty (mag).
"""
app_mag = abs_mag[0] + 5.0 * np.log10(distance[0]) - 5.0
return app_mag, abs_mag[1]
[docs]
@typechecked
def parallax_to_distance(
parallax: Union[
Tuple[float, Optional[float]], Tuple[np.ndarray, Optional[np.ndarray]]
],
) -> Union[Tuple[float, Optional[float]], Tuple[np.ndarray, Optional[np.ndarray]]]:
"""
Function for converting from parallax to distance.
Parameters
----------
parallax : tuple(float, float), tuple(np.ndarray, np.ndarray)
Parallax and optional uncertainty (mas). The
uncertainty is not used if set to ``None``,
for example, ``parallax=(2., None)``.
Returns
-------
float, np.ndarray
Distance (pc).
float, np.ndarray, None
Uncertainty (pc).
"""
# From parallax (mas) to distance (pc)
distance = 1e3 / parallax[0]
if parallax[1] is None:
distance_error = None
else:
distance_minus = distance - 1.0 / ((parallax[0] + parallax[1]) * 1e-3)
distance_plus = 1.0 / ((parallax[0] - parallax[1]) * 1e-3) - distance
distance_error = (distance_plus + distance_minus) / 2.0
return distance, distance_error
[docs]
@typechecked
def logg_to_mass(
logg: Union[float, np.ndarray], radius: Union[float, np.ndarray]
) -> Union[float, np.ndarray]:
"""
Function for converting :math:`\\log(g)` and a radius into a mass.
Parameters
----------
logg : float, np.ndarray
Log10 of the surface gravity (cgs).
radius : float, np.ndarray
Radius (Rjup).
Returns
-------
float, np.ndarray
Mass (Mjup).
"""
surface_grav = 1e-2 * 10.0**logg # (m s-2)
radius *= constants.R_JUP # (m)
mass = surface_grav * radius**2 / constants.GRAVITY # (kg)
return mass / constants.M_JUP
[docs]
@typechecked
def logg_to_radius(
logg: Union[float, np.ndarray], mass: Union[float, np.ndarray]
) -> Union[float, np.ndarray]:
"""
Function for converting :math:`\\log(g)` and a mass into a radius.
Parameters
----------
logg : float, np.ndarray
Log10 of the surface gravity (cgs).
mass : float, np.ndarray
Mass (Mjup).
Returns
-------
float, np.ndarray
Radius (Rjup).
"""
surface_grav = 1e-2 * 10.0**logg # (m s-2)
mass_kg = mass * constants.M_JUP # (kg)
radius = np.sqrt(mass_kg * constants.GRAVITY / surface_grav) # (m)
return radius / constants.R_JUP
[docs]
@typechecked
def mass_to_logg(
mass: Union[float, np.ndarray], radius: Union[float, np.ndarray]
) -> Union[float, np.ndarray]:
"""
Function for converting a mass and radius into :math:`\\log(g)`.
Parameters
----------
mass : float, np.ndarray
Mass ($M_\\mathrm{J}$).
radius : float, np.ndarray
Radius ($R_\\mathrm{J}$).
Returns
-------
float, np.ndarray
Surface gravity :math:`\\log(g)`.
"""
mass *= constants.M_JUP # (kg)
radius *= constants.R_JUP # (m)
gravity = 1e2 * mass * constants.GRAVITY / radius**2 # (cm s-2)
return np.log10(gravity)
[docs]
@typechecked
def luminosity_to_teff(
luminosity: Union[float, np.ndarray], radius: Union[float, np.ndarray]
) -> Union[float, np.ndarray]:
"""
Function for converting a luminosity and radius into :math:`T_\\mathrm{eff}`.
Parameters
----------
luminosity : float, np.ndarray
Bolometric luminosity ($L_\\odot$).
radius : float, np.ndarray
Radius ($R_\\mathrm{J}$).
Returns
-------
float, np.ndarray
Effective temperature (K).
"""
radius *= constants.R_JUP # (Rjup)
teff = (luminosity / (4.0 * np.pi * radius**2 * constants.SIGMA_SB)) ** 0.25
return teff
