ChromaStar
Author: Ian Short
Description: Model stellar atmosphere and spectrum and planetary habitable zone
Keywords: stellar atmosphere, stellar spectrum, spectral line, stellar parameters, stellar physics, stellar astronomy, astronomy teaching, astronomy education, stellar spectroscopy, stellar photometry, spectral classification, planetary habitable zone, life zone, extra-solar planets, exo-planets, greenhouse effect, albedo, climate science, environmental science, HTML graphics, HTML plotting, JavaScript graphics, JavaScript plotting, Saint Mary's University, Saint Mary's Astronomy and Physics Department, Institute for Computational Astrophysics, ICA

## ChromaStar (formerly "GrayStar")

OpenStar pedagogical star and planet modeling in JavaScript.
Visualization in HTML5. Hover for tips. Click for data coordinates. Ctrl +/- to zoom

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Optional plots: Atmosphere
Ion Eq (if Atmos plots ON)
Chem Eq (if Atmos plots ON) Radiation field

Star inputs:

Surface temperature, Tsurf
(3000 - 50000) K)
K
Log10 surface gravity, log(g)
(0.0 - 5.5 cm s-2 = dynes g-1)
Mass
(0.1 - 20.0 MSun)
MSun
Metal content
(log10 0.001 - 10.0 x solar)
κFudge log10 mass extinction (-2.0 - 2.0 log cm2 g-1)
[He/Fe] (-1 - 1)
[C/O] (-2 - 2)
[α/Fe] (-0.5 - 0.5)

Stellar outputs

Planetary inputs:
Affects Habitable zone and Transit light curve

Surface pressure
(0.6 - 22000 kPa)
kPa
Greenhouse effect, ΔT
(-200 - +600 K)
K
Albedo (0.0 - 0.95)
ROrbit (AU) (0.01 - 50)
RPlanet (REarth) (0.1 - 20)
iRot (0 - 90 o)
Organic solvent
Water Methane Ammonia Carbon dioxide

Planetary outputs

Modeling realism vs performance

ONLY update spectral line
No. HSE-EOS-Opac iters
No. Pe-IonEquil-MolecEquil iters
TiO bands (C3Δ-X3Δ, c1Φ-a1Δ, A3Φ-X3Δ)

2-level atom: Spectral line parameters

Show 2-level atom plots

Line center wavelength, λ0 (350 - 1000 nm)

Line strength:

A12 Number density (2.0 - 11.0)
Log10 Oscillator strength, log f , (-6.0 - +1.0)
Ionization stage
Stage I ground ionization E, χI (eV ) (4.0 - 25.0)
Stage II ground ionization E, χII( eV ) (5.0 - 55.0)
Stage III ground ionization E, χIII( eV ) (5.0 - 55.0)
Stage IV ground ionization E, χIV( eV ) (5.0 - 55.0)
Excitation E, χl ( eV ) (0 - χI)
Stage I ground statistical wght, g1 (unitless) (1 - 100)
Stage II ground statistical wght, g2 (unitless) (1 - 100)
Stage III ground statistical wght, g3 (unitless) (1 - 100)
Stage IV ground statistical wght, g4 (unitless) (1 - 100)
Lower E-level statistical wght, gL (unitless) (1 - 100)

Line width:

Microturbulence, ξ T , (0.0 - 4.0 km s-1)
Particle mass (1 - 60 amu)
Log10 Broadening enhancement, γExtra (0.0 - 1.0)
vMacro (0 - 8 km s-1)
vRot (0 - 20 km s-1)
iRot (0 - 90 o)

Detailed print-out (below graphs): None Atmospheric structure Flux spectral energy distribution (SED) Specific intensity distribution High resolution spectral line profile Limb darkening coeffs Partial pressures Chem Eq (See Plot section menu) Transit light curves