f18_skew_cloud

exo_skryer.opacity_cloud.f18_skew_cloud(state: Dict[str, Array], params: Dict[str, Array]) → Tuple[Array, Array, Array]

F18 continuum plus a skew-normal spectral feature with a Rayleigh size window.

The extinction efficiency is

Q_ext(λ) = clip(Q_cont(λ) + W(x) · Q_feat(λ), 0, _Q_EXT_MAX)

where the continuum follows Fisher & Heng (2018),

Q_cont = Q1 / (Q0 · x^{-a} + x^{0.2}), x = 2π r / λ,

the spectral feature is a skew-normal profile in wavelength,

Q_feat = 2 A exp(-z²/2) Φ(ξ z), z = (λ - λ0) / ω,

with Φ the standard normal CDF, and the size-parameter window

W(x) = exp(-x / x0)

suppresses the feature for large particles (geometric-optics regime), consistent with the Rayleigh origin of the absorption feature. Pure absorption is assumed (Q_sca = 0, g = 0).

Parameters:

statedict

Must contain wl (μm), q_c_lay, nlay, nwl.

paramsdict

log_10_cld_r — log₁₀ particle radius (μm) cld_rho — bulk density (g cm⁻³) cld_Q0 — continuum opacity scale cld_Q1 — continuum opacity scale cld_a — continuum power-law index cld_amp — skew-normal feature amplitude A cld_lam0 — feature central wavelength λ0 (μm) cld_omega — feature width ω (μm) cld_xi — skewness parameter ξ (0 → symmetric Gaussian) cld_x0 — size-window rolloff scale x0

Returns:

k_cldjnp.ndarray, shape (nlay, nwl)

Cloud extinction coefficient in cm² g⁻¹.

ssajnp.ndarray, shape (nlay, nwl)

Single-scattering albedo (zeros — pure absorption).

gjnp.ndarray, shape (nlay, nwl)

Asymmetry parameter (zeros).