{
 "version": 1,
 "sources": {
  "astrometry": "https://simbad.cds.unistra.fr/simbad/sim-tap",
  "stars": "https://academic.oup.com/mnras/article/400/3/1479/961439",
  "gas": "https://academic.oup.com/mnras/article/450/1/1057/1009600",
  "wideField": "https://www.eso.org/public/images/eso0926a/",
  "sitelle": "https://arxiv.org/abs/2002.05313",
  "recombination": "https://www.aanda.org/articles/aa/pdf/2014/07/aa21624-13.pdf",
  "pillarsHubble": "https://esahubble.org/images/heic1501a/",
  "pillarsMesh": "https://science.nasa.gov/asset/webb/pillars-of-creation-model-for-3d-printing/"
 },
 "provenance": "ICRS coordinates: SIMBAD TAP, 2026-10-16. Temperatures and log luminosities: Sana et al. 2009 Table 5 (parameters from Dufton et al. 2006), unresolved systems treated as one source. Not a new spectral fit. Nebular line ratios: McLeod et al. 2015 Table 2, dereddened example HII region spectrum, not a spatially resolved flux map.",
 "stars": [
  {
   "name": "HD 168076",
   "ra": 274.65175211814,
   "dec": -13.80067247661,
   "temperatureK": 41500,
   "logLuminositySolar": 5.86
  },
  {
   "name": "HD 168075",
   "ra": 274.65017430966,
   "dec": -13.79345825876,
   "temperatureK": 40000,
   "logLuminositySolar": 5.63
  },
  {
   "name": "HD 168183",
   "ra": 274.74454459282,
   "dec": -13.99123795081,
   "temperatureK": 32000,
   "logLuminositySolar": 5.39
  },
  {
   "name": "HD 168137",
   "ra": 274.73412283265,
   "dec": -13.80863681933,
   "temperatureK": 37000,
   "logLuminositySolar": 4.85
  },
  {
   "name": "BD-13 4930",
   "ra": 274.71947877202,
   "dec": -13.82850959893,
   "temperatureK": 34000,
   "logLuminositySolar": 4.84
  },
  {
   "name": "BD-13 4927",
   "ra": 274.66705772571,
   "dec": -13.75516756436,
   "temperatureK": 36000,
   "logLuminositySolar": 5.75
  },
  {
   "name": "BD-13 4929",
   "ra": 274.69104350833,
   "dec": -13.77524946726,
   "temperatureK": 36000,
   "logLuminositySolar": 5.24
  },
  {
   "name": "BD-13 4928",
   "ra": 274.67823407409,
   "dec": -13.78082499687,
   "temperatureK": 32500,
   "logLuminositySolar": 4.77
  }
 ],
 "linesRelativeHbeta": [
  {
   "name": "H beta",
   "nm": 486.142,
   "ratio": 1
  },
  {
   "name": "[O III]",
   "nm": 495.901,
   "ratio": 0.419
  },
  {
   "name": "[O III]",
   "nm": 500.693,
   "ratio": 1.297
  },
  {
   "name": "He I",
   "nm": 587.576,
   "ratio": 0.179
  },
  {
   "name": "[O I]",
   "nm": 630.039,
   "ratio": 0.269
  },
  {
   "name": "[O I]",
   "nm": 636.386,
   "ratio": 0.084
  },
  {
   "name": "[N II]",
   "nm": 654.812,
   "ratio": 0.21
  },
  {
   "name": "H alpha",
   "nm": 656.289,
   "ratio": 4.343
  },
  {
   "name": "[N II]",
   "nm": 658.35,
   "ratio": 0.652
  },
  {
   "name": "He I",
   "nm": 667.824,
   "ratio": 0.055
  },
  {
   "name": "[S II]",
   "nm": 671.656,
   "ratio": 0.129
  },
  {
   "name": "[S II]",
   "nm": 673.094,
   "ratio": 0.093
  },
  {
   "name": "He I",
   "nm": 706.537,
   "ratio": 0.029
  },
  {
   "name": "[Ar III]",
   "nm": 713.589,
   "ratio": 0.139
  },
  {
   "name": "[Ar III]",
   "nm": 775.119,
   "ratio": 0.069
  }
 ],
 "lineNotes": "Ratios normalized to the measured dereddened H-alpha=4.343 when scaling from case-B emissivity. The example spectrum is not an ideal case-B Balmer decrement. 5577 A omitted because the spectrum contains terrestrial sky contamination. Optical subset only; no complete IR/UV spectrum.",
 "gasConstraints": {
  "ambientElectronDensityUpperCm3": 250,
  "tipElectronDensityCm3": 2000,
  "temperatureK": 10000,
  "halphaCoefficientErgCm3S": 3.56e-25
 },
 "assumptions": {
  "clusterDepthLy": 3.2,
  "clusterDepthNote": "Common plane 3.2 ly behind the pillar plane for all eight systems, consistent only qualitatively with McLeod 2015 section 4.2; individual stellar depths are unknown. Angular positions retained at the simulation distance.",
  "pressStretchExponent": 2.4,
  "pressStretchNote": "Press JPEGs are display-stretched; linear radiance is approximated by (value/255)^exponent. Absolute photometric calibration of the photographs is not available.",
  "peakEmissionMeasureCm6Ly": 100000,
  "peakEmissionMeasureNote": "1e5 cm^-6 ly (3e5 cm^-6 pc) assigned to the brightest wide-field region: about 100 cm^-3 along ~10 ly, below the 250 cm^-3 ambient bound of McLeod 2015 and the same order as the previous reconstruction (194 cm^-3 over 2 ly). Beam-averaged H-alpha surveys suggest lower surface brightness (a few thousand Rayleigh); this is an upper plausible value, kept fixed together with the stellar display exposure, never adapted.",
  "maxMeasuredOpticalDepth": 4.5,
  "pillarExtinctionPerLy": 6.0,
  "pillarVoxelLy": 0.045,
  "envelopeScaleLy": 0.7,
  "wideFieldHalfWidthLy": 32.0,
  "nearFieldHalfWidthLy": 6.0,
  "dustAlbedo": 0.5,
  "dustAsymmetry": 0.6,
  "dustPhaseFunction": "Henyey-Greenstein g=0.6 single scattering toward the on-axis observer; effective extinction grey in the optical.",
  "depthModel": {
   "extinctionCentreLy": 8.5,
   "extinctionSigmaLy": 2.0,
   "extinctionRangeLy": [
    -1.0,
    12.5
   ],
   "emissionCentreLy": 15.0,
   "emissionSigmaLy": 3.0,
   "emissionRangeLy": [
    -6.0,
    24.0
   ],
   "emissionFloor": 0.02,
   "note": "Layers are sheets with thickness: the sky-plane pattern of each layer is read where the ray crosses the layer centre, and only its opacity/emission is spread along the depth profile, so photographic structure is never smeared radially by the extrusion. Recombination emission: sheet 15 ly behind the pillar plane (behind every mesh component, as the ionized cloud face lies behind the pillars seen from Earth) with a 2% floor across the range, blurred where it lies in front of the pillars (a faint veil). Lanes and the dark parent cloud: 8.5 ly, near the base of the farthest, largest pillar, where the photograph shows them merging. Pillar detail is anchored at each column’s own depth centre from the mesh."
  },
  "morphology": "Sky-plane structure from ESO0926a (wide field) and heic1501a (pillars) after star removal and inversion of the press stretch; no deprojected observed density cube. The NASA/STScI mesh supplies pillar depths after registration to the Hubble silhouette.",
  "viewing": "Fixed existing SDR display transform, clear window, no simulated eye adaptation. Absolute screen luminance and cabin glare are not calibrated.",
  "sourceBlendScaleLy": 0.08,
  "envelopeNote": "Emission envelope = soft maximum over 0.7 ly; everything darker than it at smaller scales is treated as absorbing material in front of the emission. This is the ambiguity of a single photograph, resolved by one rule rather than by measurement.",
  "wideFieldFeatherLy": 4.0,
  "baseExtensionLy": 1.6,
  "baseExtensionNote": "The NASA/STScI print model is cut flat at its base. Each column is continued 1.6 ly below the cut along the mesh down axis with a fading density, so the pillars merge into the dark parent cloud of the photograph instead of ending on a straight edge.",
  "opacityGain": 2.6,
  "opacityNote": "tau_true = tau_photo (1 + 2.6 tau_photo): pillar bodies (photographic contrast ~3:1, tau ~1.1) become opaque (tau ~4); faint lanes (tau ~0.3) barely change. The press photograph cannot separate an opaque body from the glow in front of it; this rule declares that separation.",
  "boxFeatherLy": 1.0,
  "depthBlendLy": 0.8,
  "slabSigmaLy": 0.35,
  "veilNote": "Brightness remaining over an absorber (observed minus the attenuated background) is placed as emission just in front of it, over 1.4 ly, with the lines/continuum split of the local photographic colour. Pillar bases are bright because the photograph shows more such light there; tips are dark."
 },
 "imageMetadata": {
  "eso0926a": {
   "credit": "ESO",
   "license": "CC BY 4.0",
   "pixels": [
    8084,
    8084
   ],
   "fieldArcmin": [
    32.08,
    32.08
   ],
   "centreRaDec": [
    "18 18 48.01",
    "-13 49 11.83"
   ],
   "orientation": "north up, east left",
   "filters": "B 451 nm, V 539 nm, R 651 nm",
   "fileUsed": "cdn.eso.org/images/large/eso0926a.jpg"
  },
  "heic1501a": {
   "credit": "NASA, ESA/Hubble and the Hubble Heritage Team",
   "license": "CC BY 4.0",
   "pixels": [
    6780,
    7071
   ],
   "fieldArcmin": [
    4.53,
    4.72
   ],
   "orientation": "north 35 deg left of vertical (page); registered numerically on ESO0926a",
   "filters": "[O III] 502 nm, H-alpha 657 nm, [S II] 673 nm",
   "fileUsed": "cdn.esahubble.org/archives/images/large/heic1501a.jpg"
  }
 }
}