ActiveStar#

class fleck.jax.ActiveStar(times=Array([], dtype=float32), lon=Array([], dtype=float32), lat=Array([], dtype=float32), rad=Array([], dtype=float32), spectrum=Array([], dtype=float32), T_eff=None, temperature=Array([], dtype=float32), inclination=Array([], dtype=float32), wavelength=None, phot=None, P_rot=3.3)[source]#

Bases: object

Model for a star with active regions and rotation, with optional planetary transit models and spot occultations.

Parameters:

timesarray: Times at which to compute the flux
lonarray: Active region longitudes in radians on (0, 2pi)
latarray: Active region latitudes in radians on (0, pi)
radarray: Active region radii in units of stellar radii
spectrumarray: One spectrum for each active region
T_effarray: Effective temperature of the photosphere
temperaturearray: Effective temperature of the active regions
inclinationarray: Stellar inclination [radians]
wavelengtharray: Wavelength for each flux observation in phot [meters]
photarray: Photospheric flux at each wavelength.
P_rotfloat: Stellar rotation period

Attributes Summary

`key`
`n_mc`

Methods Summary

`add_spot`(lon, lat, rad[, contrast, ...])	Add an active region to the stellar model.
`limb_darkening`(mu, u1, u2)	Compute quadratic limb darkening as a function of \(\mu\).
`plot_star`(t0, rp, a, inclination[, ecc, ...])	Plot a 2D representation of the star and transit chord.
`rotation_model`([f0, t0_rot, u1, u2])	Spectrophotometry of stellar rotation.
`spot_coords`([times, t0_rot])	Compute the spatial coordinates and projected dimensions of active regions.
`transit_model`(t0, period, rp, a, inclination)	Compute spectrophotometry with rotation and a planetary transit.
`tree_flatten`()
`tree_unflatten`(aux_data, children)

Attributes Documentation

key = Array([0, 0], dtype=uint32)#

n_mc = 1000#

Methods Documentation

add_spot(lon, lat, rad, contrast=None, temperature=None, spectrum=None)[source]#

Add an active region to the stellar model.

Parameters:

lonfloat: Active region longitudes in radians on (0, 2pi)
latfloat: Active region latitudes in radians on (0, pi)
radfloat: Active region radii in units of stellar radii
contrastfloat: Ratio of the active region’s flux to the photospheric flux at each ActiveStar.wavelength
spectrumfloat: The spectrum of the active region on the same wavelength grid is ActiveStar.phot

limb_darkening(mu, u1, u2)[source]#: Compute quadratic limb darkening as a function of \(\mu\).

plot_star(t0, rp, a, inclination, ecc=0, t0_rot=0, multiply_radii=1, ax=None, annotate=False)[source]#

Plot a 2D representation of the star and transit chord.

Parameters:

t0float: Mid-transit time
rpfloat: Exoplanet radius in units of stellar radii
afloat: Planetary semi-major axis in units of stellar radii
inclinationfloat: Planetary orbital inclination [radians]
eccfloat: Orbital eccentricity, default is zero.
t0_rotfloat: Zero-point in time for stellar rotation, default is zero
multiply_radiifloat: Visually represent scaled-up active regions where the radii are increased by factor multiply_radii, default is one.
axmatplotlib.axes.Axes: Add the visualization to this matplotlib axis
annotatebool: Add a text label with active region indices and temperatures to the visualization

rotation_model(f0=0, t0_rot=0, u1=0, u2=0)[source]#

Spectrophotometry of stellar rotation.

Parameters:

f0float: Baseline flux of an unspotted star (usually zero or one)
t0_rotfloat: Zero-point reference time for stellar rotation

Returns:

spot_modelarray: Flux as a function of time and wavelength

spot_coords(times=None, t0_rot=0)[source]#

Compute the spatial coordinates and projected dimensions of active regions.

Parameters:

timesarray: Times on which to compute spectrophotometry
t0_rotfloat: Zero-point reference time for stellar rotation

Returns:

spot_position_xarray: x-position of the active region in the observer oriented coordinate system [1].
spot_position_yarray: y-position of the active region in the observer oriented coordinate system [1].
spot_position_zarray: y-position of the active region in the observer oriented coordinate system [1].
major_axisarray: Apparent semimajor axis of the circular active region, which is elliptical when projected active onto the sky plane (in general)
minor_axisarray: Apparent semiminor axis of the circular active region, which is elliptical when projected active onto the sky plane (in general)
anglearray: Angle between the +x-axis and the projected active region’s semimajor axis
radarray: Active region radius [stellar radii]
contrast: array: Ratio of the active region spectrum and the photosphere spectrum

References

[1] (1,2,3)

Fabrycky & Winn (2009) https://arxiv.org/abs/0902.0737

transit_model(t0, period, rp, a, inclination, omega=1.5707963267948966, ecc=0, f0=1, t0_rot=0, u1=0, u2=0)[source]#

Compute spectrophotometry with rotation and a planetary transit.

The transit is computed with jaxoplanet for a star with quadratic limb darkening.

Parameters:

t0float: Mid-transit time
periodfloat: Orbital period of the transiting planet
rpfloat: Exoplanet radius in units of stellar radii
afloat: Planetary semi-major axis in units of stellar radii
inclinationfloat: Planetary orbital inclination [radians]
omegafloat: Argument of periapse [radians], default is \(\pi/2\).
eccfloat: Orbital eccentricity, default is zero.
f0float: Out-of-transit flux for an unspotted star, default is one.
t0_rotfloat: Zero-point in time for stellar rotation, default is zero
u1float: Limb-darkening parameter \(u_1\)
u2float: Limb-darkening parameter \(u_2\)

Returns:

lcarray

Flux as a function of time and wavelength

apparent_rprs2array

The apparent squared ratio of planet-to-star radius with stellar spectral contamination by active regions

Xarray: x-position of the planet in the observer oriented coordinate system [1].
Yarray: y-position of the planet in the observer oriented coordinate system [1].

References

[1] (1,2)

Fabrycky & Winn (2009) https://arxiv.org/abs/0902.0737

tree_flatten()[source]#

classmethod tree_unflatten(aux_data, children)[source]#