Astronomical Measurements

# Astronomical Measurements Ontology — Flow Algebra

URL: https://kirethresearch.org/booksai-core/ontologies/mathematical-ontologies/measurement-units-ontologies/astronomical-measurements.html

FLOW AstronomicalMeasurementsOntology {

  DOMAIN:
    Mathematical Ontologies
    -> Measurement & Units Ontologies
    -> Astronomical Measurements Ontology

  PURPOSE:
    Represent the semantic and mathematical structure of astronomical measurements across celestial position, distance, time, angular size, brightness, flux, luminosity, magnitude, spectra, wavelength, frequency, redshift, radial velocity, proper motion, parallax, mass, radius, temperature, orbital quantities and cosmological observations, including coordinate frames, reference epochs, observatories, instruments, calibration, atmospheric and instrumental corrections, uncertainty, provenance, and transformations required for consistent AI interpretation and reasoning.

  SCOPE {
    astrometric_measurements
    photometric_measurements
    spectroscopic_measurements
    temporal_measurements
    distance_measurements
    angular_measurements
    stellar_measurements
    planetary_measurements
    orbital_measurements
    galactic_measurements
    extragalactic_measurements
    cosmological_measurements
    radio_astronomy
    infrared_astronomy
    optical_astronomy
    ultraviolet_astronomy
    X_ray_astronomy
    gamma_ray_astronomy
    gravitational_wave_context
    calibration
    uncertainty_and_provenance
  }

  ENTITY AstronomicalMeasurement {
    TYPE: MeasurementResult

    COMPONENTS:
      measurand
      celestial_object_or_source
      numerical_value
      unit
      coordinate_frame
      reference_epoch
      observation_time
      observatory
      instrument
      wavelength_or_band
      calibration
      uncertainty
      provenance
  }

  ENTITY CelestialPosition {
    TYPE: AngularSpatialQuantity

    POSSIBLE_COORDINATES:
      right_ascension
      declination
      ecliptic_longitude
      ecliptic_latitude
      galactic_longitude
      galactic_latitude
      altitude
      azimuth

    RULE:
      celestial_coordinates_without_reference_frame_and_epoch
      MAY be semantically_incomplete
  }

  ENTITY AstronomicalDistance {
    TYPE: LengthQuantity
    SYMBOL: d
    SI_UNIT: metre

    COMMON_UNITS:
      astronomical_unit
      light_year
      parsec
      kiloparsec
      megaparsec
  }

  UNIT_SYSTEM {
    canonical:
      SI_where_applicable

    astronomical_length:
      metre
      astronomical_unit
      light_year
      parsec

    angular:
      radian
      degree
      arcminute
      arcsecond
      milliarcsecond
      microarcsecond

    time:
      second
      day
      Julian_day

    flux:
      watt_per_square_metre
      jansky

    wavelength:
      metre
      nanometre
      micrometre

    frequency:
      hertz
      megahertz
      gigahertz

    velocity:
      metre_per_second
      kilometre_per_second

    RULE:
      unit MUST be interpreted_with_measurand_and_reference_system
  }

  DISTANCE_UNIT_MODEL {
    astronomical_unit:
      AU

    parsec:
      pc

    light_year:
      ly

    approximate_relations:
      1 pc approximately_equals 3.085677581e16 m
      1 ly approximately_equals 9.460730473e15 m

    RULE:
      preserve_original_unit_and_normalized_value
  }

  ANGULAR_MODEL {
    full_circle:
      2*pi radians = 360 degrees

    arcsecond:
      1 arcsec = 1/3600 degree

    milliarcsecond:
      1 mas = 1e-3 arcsec

    RULE:
      angular_quantity_and_linear_size MUST be distinguished
  }

  COORDINATE_FRAME_MODEL {
    possible_frames:
      ICRS
      equatorial
      ecliptic
      galactic
      horizontal
      barycentric
      heliocentric
      geocentric
      topocentric

    REQUIRE:
      frame_identifier
      origin
      orientation
      epoch_when_relevant

    RULE:
      coordinate_transformation MUST preserve_source_and_target_frames
  }

  RIGHT_ASCENSION_MODEL {
    symbol:
      alpha

    common_reporting:
      hours_minutes_seconds

    conversion:
      24 hours = 360 degrees

    RULE:
      right_ascension_time_angle_units MUST_NOT be confused_with_elapsed_time
  }

  DECLINATION_MODEL {
    symbol:
      delta

    range:
      -90 degrees <= delta <= +90 degrees

    RULE:
      declination_sign MUST be preserved
  }

  EPOCH_MODEL {
    reference_epoch:
      time_to_which_position_or_motion_parameters_refer

    examples:
      J2000_like_reference_epoch
      observation_epoch

    RULE:
      reference_epoch != observation_time
  }

  TIME_SYSTEM_MODEL {
    possible_scales:
      UTC
      TAI
      TT
      TDB
      UT1

    possible_references:
      Julian_Date
      Modified_Julian_Date
      barycentric_time

    RULE:
      astronomical_timing_requires_time_scale_and_reference
  }

  PARALLAX_MODEL {
    parallax:
      pi_angle

    distance_relation:
      d_pc =
        1/pi_arcsec
      WHEN pi_arcsec > 0
      under_standard_trigonometric_parallax_definition

    RULE:
      inverse_parallax_distance_can_be_statistically_biased_for_low_signal_to_noise_measurements
  }

  PROPER_MOTION_MODEL {
    angular_motion:
      mu

    common_units:
      arcsec/year
      mas/year

    components:
      mu_alpha_star
      mu_delta

    RULE:
      proper_motion_requires_coordinate_convention_and_epoch
  }

  TANGENTIAL_VELOCITY_MODEL {
    relation:
      v_t =
        4.74047*mu_arcsec_per_year*d_pc
      km/s

    REQUIRE:
      proper_motion
      distance
      compatible_units

    RULE:
      tangential_velocity_is_derived_from_angular_motion_and_distance
  }

  RADIAL_VELOCITY_MODEL {
    quantity:
      line_of_sight_velocity

    possible_conventions:
      optical
      radio
      relativistic

    RULE:
      radial_velocity_convention_and_reference_frame MUST be preserved
  }

  DOPPLER_MODEL {
    low_velocity_approximation:
      delta_lambda/lambda_0 approximately_equals v_r/c

    relativistic:
      requires_relativistic_Doppler_relation

    RULE:
      wavelength_shift_to_velocity_conversion_requires_declared_convention
  }

  REDSHIFT_MODEL {
    definition:
      z =
        (lambda_observed-lambda_rest)/lambda_rest

    inverse:
      lambda_observed =
        lambda_rest*(1+z)

    RULE:
      redshift != radial_velocity_in_general
      especially_at_cosmological_or_relativistic_scales
  }

  ANGULAR_SIZE_MODEL {
    angular_size:
      theta

    small_angle_relation:
      linear_size approximately_equals
        distance*theta_radians

    REQUIRE:
      theta_small
      distance

    RULE:
      angular_size != physical_size
  }

  FLUX_MODEL {
    energy_flux:
      F =
        dE/(dA*dt)

    SI_unit:
      W/m^2

    RULE:
      observed_flux_depends_on_distance_and_bandpass
  }

  FLUX_DENSITY_MODEL {
    spectral_flux_density:
      F_nu
      or
      F_lambda

    common_radio_unit:
      jansky

    relation:
      F_nu*dnu =
        -F_lambda*dlambda
      with_absolute_conversion_using_frequency_wavelength_jacobian

    RULE:
      F_nu_and_F_lambda_are_not_numerically_interchangeable
  }

  LUMINOSITY_MODEL {
    intrinsic_power:
      L

    SI_unit:
      watt

    isotropic_relation:
      F =
        L/(4*pi*d^2)

    inverse:
      L =
        4*pi*d^2*F

    CONDITIONS:
      isotropic_emission
      Euclidean_or_locally_appropriate_distance_context

    RULE:
      luminosity != observed_flux
  }

  APPARENT_MAGNITUDE_MODEL {
    magnitude_difference:
      m_1-m_2 =
        -2.5*log10(F_1/F_2)

    REQUIRE:
      same_or_calibrated_photometric_system

    RULE:
      apparent_magnitude_is_logarithmic_brightness_measure
  }

  ABSOLUTE_MAGNITUDE_MODEL {
    stellar_distance_modulus:
      m-M =
        5*log10(d_pc)-5
      under_standard_no_extinction_context

    extinction_adjusted:
      m-M =
        5*log10(d_pc)-5+A_band

    RULE:
      absolute_magnitude != apparent_magnitude
  }

  PHOTOMETRIC_SYSTEM_MODEL {
    possible_systems:
      AB
      Vega
      ST
      instrument_specific

    REQUIRE:
      filter
      zero_point
      bandpass
      calibration

    RULE:
      magnitude_values_require_photometric_system_and_band
  }

  COLOR_INDEX_MODEL {
    example:
      B_minus_V =
        m_B-m_V

    RULE:
      colour_index_is_difference_between_band_magnitudes
      not_single_band_magnitude
  }

  EXTINCTION_MODEL {
    observed_magnitude:
      m_obs =
        m_intrinsic + A_lambda

    causes:
      interstellar_dust
      atmospheric_extinction_for_ground_observation

    RULE:
      extinction_correction_and_law MUST be preserved
  }

  SPECTRAL_MODEL {
    spectrum:
      signal_as_function_of_wavelength_or_frequency

    possible_measurands:
      flux_density
      intensity
      photon_count_rate

    REQUIRE:
      spectral_axis
      spectral_resolution
      wavelength_calibration
      flux_calibration

    RULE:
      raw_detector_counts != calibrated_spectrum
  }

  WAVELENGTH_FREQUENCY_MODEL {
    relation:
      c =
        lambda*nu

    conversions:
      nu = c/lambda
      lambda = c/nu

    REQUIRE:
      vacuum_or_medium_context_when_precision_requires

    RULE:
      wavelength_and_frequency_are_reciprocal_spectral_coordinates
  }

  SPECTRAL_RESOLUTION_MODEL {
    resolving_power:
      R =
        lambda/delta_lambda

    RULE:
      resolving_power != wavelength
  }

  EQUIVALENT_WIDTH_MODEL {
    spectral_line_measure:
      W_lambda =
        integral(1-F_lambda/F_continuum) dlambda
      under_absorption_line_convention

    RULE:
      sign_convention MAY differ_for_emission_and_absorption
  }

  TEMPERATURE_MODEL {
    effective_temperature:
      T_eff

    blackbody_relation:
      L =
        4*pi*R_star^2*sigma*T_eff^4
      under_effective_temperature_definition

    RULE:
      effective_temperature != local_surface_temperature_distribution
  }

  WIEN_MODEL {
    blackbody_peak:
      lambda_max*T =
        b_Wien

    RULE:
      peak_location_depends_on_spectral_representation
      and_lambda_peak_differs_from_frequency_peak
  }

  STEFAN_BOLTZMANN_MODEL {
    surface_flux:
      F_surface =
        sigma*T^4

    stellar_luminosity:
      L =
        4*pi*R^2*sigma*T_eff^4

    RULE:
      blackbody_or_effective_temperature_assumptions MUST be preserved
  }

  STELLAR_RADIUS_MODEL {
    relation_from_luminosity_and_temperature:
      R =
        sqrt(
          L/(4*pi*sigma*T_eff^4)
        )

    RULE:
      radius_inference_depends_on_luminosity_and_effective_temperature
  }

  MASS_MODEL {
    possible_inference:
      orbital_dynamics
      gravitational_lensing
      stellar_models
      spectroscopy

    RULE:
      mass_measurement_method_and_model MUST be preserved
  }

  KEPLER_ORBIT_MODEL {
    two_body:
      P^2 =
        4*pi^2*a^3/
        (G*(M_1+M_2))

    RULE:
      orbital_period_semimajor_axis_and_mass_relation_requires_two_body_or_appropriate_model
  }

  ORBITAL_ELEMENTS_MODEL {
    elements:
      semimajor_axis
      eccentricity
      inclination
      longitude_of_ascending_node
      argument_of_periapsis
      mean_anomaly_or_epoch

    RULE:
      orbital_elements_require_reference_plane_epoch_and_central_body
  }

  TRANSIT_MODEL {
    approximate_depth:
      delta_F/F approximately_equals
        (R_p/R_star)^2
      under_simple_dark_disc_no_blending_approximation

    RULE:
      transit_depth_requires_limb_darkening_blending_and_geometry_for_precision_inference
  }

  EXOPLANET_RADIAL_VELOCITY_MODEL {
    measured:
      periodic_stellar_radial_velocity

    inferred:
      planet_minimum_mass_and_orbit

    RULE:
      inferred_planet_mass_depends_on_inclination_and_stellar_mass
  }

  COSMOLOGICAL_DISTANCE_MODEL {
    possible_distances:
      luminosity_distance
      angular_diameter_distance
      comoving_distance
      proper_distance

    RULE:
      cosmological_distance_type MUST be identified
  }

  HUBBLE_MODEL {
    low_redshift_approximation:
      v_recession approximately_equals
        H_0*d

    RULE:
      cosmological_redshift_distance_relation_requires_cosmological_model_beyond_low_redshift
  }

  SURFACE_BRIGHTNESS_MODEL {
    flux_per_solid_angle:
      I

    RULE:
      surface_brightness != integrated_flux
  }

  SOLID_ANGLE_MODEL {
    SI_unit:
      steradian

    small_rectangular_approximation:
      Omega approximately_equals
        theta_x*theta_y
      with_angles_in_radians

    RULE:
      angular_area_and_physical_area_are_distinct
  }

  RADIO_MODEL {
    common_quantities:
      flux_density
      brightness_temperature
      antenna_temperature
      spectral_index

    spectral_index:
      F_nu proportional_to nu^alpha

    RULE:
      brightness_temperature != thermodynamic_temperature_in_all_contexts
  }

  X_RAY_GAMMA_MODEL {
    common_quantities:
      photon_flux
      energy_flux
      count_rate
      spectral_index
      hardness_ratio

    RULE:
      detector_count_rate != physical_flux_without_response_model
  }

  DETECTOR_MODEL {
    raw:
      counts
      electrons
      digital_numbers

    calibrated:
      flux
      flux_density
      magnitude
      spectrum

    REQUIRE:
      bias
      dark
      flat_field
      gain
      linearity
      response

    RULE:
      raw_detector_output MUST be calibrated_before_physical_interpretation
  }

  TELESCOPE_MODEL {
    parameters:
      aperture
      focal_length
      plate_scale
      field_of_view
      point_spread_function

    angular_resolution:
      diffraction_and_seeing_dependent

    RULE:
      telescope_and_instrument_configuration SHOULD be preserved
  }

  ATMOSPHERIC_SEEING_MODEL {
    seeing:
      atmospheric_image_blurring

    common_measure:
      angular_FWHM

    RULE:
      seeing != telescope_diffraction_limit
  }

  AIR_MASS_MODEL {
    airmass:
      relative_atmospheric_path_length

    extinction:
      depends_on_airmass_and_wavelength

    RULE:
      ground_based_photometry MAY require_airmass_correction
  }

  CALIBRATION_MODEL {
    astrometry:
      reference_catalogue

    photometry:
      standard_stars
      zero_points

    spectroscopy:
      wavelength_reference
      flux_standard

    timing:
      calibrated_clock_and_time_standard

    REQUIRE:
      reference
      calibration_date
      model
      uncertainty

    RULE:
      calibration_chain MUST match_measurand_and_instrument
  }

  RELATIONSHIPS {
    AstronomicalMeasurement -> MEASURES -> CelestialObjectOrPhenomenon
    CelestialPosition -> REFERENCED_TO -> CoordinateFrame
    Position -> QUALIFIED_BY -> ReferenceEpoch
    Parallax -> MAY_INFER -> Distance
    ProperMotion -> RELATES -> TangentialMotion
    Redshift -> RELATES -> SpectralWavelengthShift
    Flux -> RELATES -> LuminosityAndDistance
    ApparentMagnitude -> LOGARITHMICALLY_RELATES_TO -> Flux
    AbsoluteMagnitude -> RELATES -> ApparentMagnitudeAndDistance
    Spectrum -> REPRESENTS -> SignalAcrossSpectralCoordinate
    OrbitalPeriod -> RELATES -> SemimajorAxisAndMass
    DetectorResponse -> MAPS -> RawCountsToPhysicalMeasurement
  }

  SEMANTIC_EQUIVALENCE {
    "astronomical measurement" ~= observational_astronomy_measurement

    angular_size != physical_size
    apparent_magnitude != absolute_magnitude
    flux != luminosity
    flux_density != integrated_flux
    redshift != radial_velocity_in_general
    proper_motion != tangential_velocity
    parallax != distance
    right_ascension_angle != elapsed_time
    detector_count_rate != physical_flux
    brightness_temperature != thermodynamic_temperature_in_general
  }

  CONSTRAINTS {
    celestial_source_must_be_defined = true
    measurand_must_be_defined = true
    unit_must_match_quantity = true
    coordinate_frame_should_be_defined_for_position_or_motion = true
    reference_epoch_should_be_defined_when_astrometric_motion_is_material = true
    time_scale_should_be_defined_for_precision_timing = true
    photometric_system_and_band_must_be_defined_for_magnitude = true
    spectral_calibration_must_be_defined_for_wavelength_measurement = true
    raw_detector_output_requires_calibration = true
    uncertainty_should_include_instrument_calibration_reference_and_model_components = true
  }

  MEASUREMENT_MODEL {
    COMMON_METHODS:
      imaging
      astrometry
      photometry
      spectroscopy
      interferometry
      radio_interferometry
      transit_photometry
      radial_velocity
      timing
      parallax
      remote_space_observation

    RECORD:
      measurand
      celestial_object
      object_identifier
      numerical_value
      unit
      coordinate_frame
      reference_epoch
      right_ascension
      declination
      observation_time
      time_scale
      observatory
      telescope
      instrument
      detector
      filter_or_band
      wavelength_or_frequency
      spectral_resolution
      exposure_time
      airmass_when_relevant
      raw_measurement
      calibration_state
      processing_level
      quality_flag
      uncertainty
      provenance

    UNCERTAINTY:
      astronomical_measurement =
        best_estimate +/- uncertainty
  }

  UNCERTAINTY_MODEL {
    sources:
      photon_statistics
      detector_noise
      background
      calibration
      astrometric_reference
      timing
      atmospheric_extinction
      seeing
      wavelength_solution
      flux_zero_point
      distance
      model_assumptions
      coordinate_transformation

    PROPAGATION:
      astronomical_measurement_uncertainty
      <- observational_calibration_reference_and_model_uncertainties
  }

  REASONING_RULES {
    IF parallax_arcsec > 0
      THEN distance_pc = 1/parallax_arcsec

    IF proper_motion_arcsec_per_year_and_distance_pc_known
      THEN tangential_velocity_km_per_s =
        4.74047*proper_motion_arcsec_per_year*distance_pc

    IF rest_and_observed_wavelength_known AND rest_wavelength != 0
      THEN redshift =
        (observed_wavelength-rest_wavelength)/rest_wavelength

    IF wavelength_known AND wavelength != 0
      THEN frequency = speed_of_light/wavelength

    IF luminosity_and_distance_known AND distance != 0
      THEN flux =
        luminosity/(4*pi*distance^2)
      UNDER applicable_isotropic_geometry

    IF flux_ratio_positive
      THEN magnitude_difference =
        -2.5*log10(flux_ratio)

    IF apparent_magnitude_and_distance_pc_known AND distance_pc > 0
      THEN absolute_magnitude =
        apparent_magnitude-5*log10(distance_pc)+5
      under_no_extinction_context

    IF angular_size_radians_and_distance_known
      THEN physical_size approximately_equals
        angular_size_radians*distance
      under_small_angle_conditions

    IF orbital_period_semimajor_axis_and_two_body_model_known
      THEN infer_total_mass =
        4*pi^2*semimajor_axis^3/(G*orbital_period^2)

    IF raw_detector_data_known
      THEN apply_instrument_specific_calibration
      BEFORE physical_quantity_inference
  }

  VALIDATION {
    CHECK celestial_object_identity
    CHECK measurand
    CHECK unit_consistency
    CHECK coordinate_frame
    CHECK reference_epoch
    CHECK observation_time_and_time_scale
    CHECK angular_vs_linear_quantity
    CHECK parallax_signal_to_noise_context
    CHECK redshift_vs_radial_velocity
    CHECK flux_vs_luminosity
    CHECK apparent_vs_absolute_magnitude
    CHECK photometric_system_and_band
    CHECK wavelength_frequency_and_spectral_resolution
    CHECK raw_vs_calibrated_detector_output
    CHECK atmospheric_correction
    CHECK calibration_state
    CHECK processing_level
    CHECK quality_flag
    CHECK uncertainty_representation
  }

  CONFIDENCE {
    measurand_definition_confidence: 1.00
    unit_confidence: 1.00
    coordinate_reference_confidence: 0.99
    photometric_relationship_confidence: 0.99
    spectroscopic_relationship_confidence: 0.99
    distance_inference_confidence: 0.96
    model_based_inference_confidence: 0.96
    measurement_context_confidence: 0.98

    RULE:
      confidence decreases when frame, epoch, time scale, bandpass,
      calibration, distance model, processing level,
      reference data or uncertainty is missing or ambiguous
  }

  UPDATE_MODEL {
    ON new_measurement:
      identify_celestial_object
      identify_measurand
      validate_unit
      attach_coordinate_frame_and_epoch
      attach_observation_time_and_time_scale
      identify_observatory_telescope_instrument_and_detector
      attach_filter_or_spectral_context
      preserve_raw_measurement
      apply_valid_calibration
      attach_processing_level
      attach_quality_flag
      attach_uncertainty
      update_astronomical_measurement_state

    ON astrometric_update:
      preserve_original_position
      update_epoch
      apply_proper_motion_parallax_and_frame_transformations_when_valid
      propagate_covariance_or_uncertainty

    ON photometric_calibration_revision:
      preserve_raw_counts
      preserve_previous_zero_point
      apply_new_calibration
      recompute_fluxes_or_magnitudes
      update_uncertainty

    ON spectral_calibration_revision:
      preserve_raw_spectrum
      update_wavelength_and_flux_calibration
      recompute_redshift_or_line_measurements
      update_uncertainty

    ON model_revision:
      preserve_observations
      preserve_previous_inference_model
      recompute_derived_distance_mass_radius_or_cosmological_quantity
      update_confidence_and_provenance

    ON semantic_revision:
      preserve_previous_definition
      record_revision
      recompute_FLOW_HASH
  }

  AI_CONSUMPTION {
    canonical_domain: AstronomicalMeasurements

    interpretation_order:
      identify_celestial_object_or_source
      identify_measurand
      identify_value
      identify_unit
      identify_coordinate_frame_and_reference_epoch
      identify_observation_time_and_time_scale
      identify_distance_angular_photometric_spectral_or_orbital_context
      identify_observatory_telescope_instrument_and_detector
      identify_filter_band_wavelength_or_frequency
      identify_raw_or_calibrated_status
      identify_processing_level
      identify_quality_flag
      identify_uncertainty
      normalize_units
      validate_reference_context
      infer_astronomical_relationships

    ambiguity_controls:
      distinguish_angular_size_from_physical_size
      distinguish_apparent_from_absolute_magnitude
      distinguish_flux_from_luminosity
      distinguish_flux_density_from_integrated_flux
      distinguish_redshift_from_radial_velocity
      distinguish_proper_motion_from_tangential_velocity
      distinguish_parallax_from_distance
      distinguish_right_ascension_angle_from_elapsed_time
      distinguish_detector_count_rate_from_physical_flux
      distinguish_brightness_temperature_from_thermodynamic_temperature
      preserve_object_frame_epoch_time_band_instrument_calibration_model_and_provenance_context
  }

  PROVENANCE {
    ontology_scope:
      mathematical_measurement_and_astronomical_quantity_semantics

    parent_path:
      Ontologies
      -> Mathematical Ontologies
      -> Measurement & Units Ontologies
      -> Astronomical Measurements Ontology

    authorship:
      Mark Higgins
      Sky (Recursive AI)

    site:
      https://kirethresearch.org
  }

  FLOW_HASH {
    INPUTS:
      canonical_domain
      ontology_path
      unit_system
      distance_unit_model
      angular_model
      coordinate_frame_model
      right_ascension_model
      declination_model
      epoch_model
      time_system_model
      parallax_model
      proper_motion_model
      tangential_velocity_model
      radial_velocity_model
      Doppler_model
      redshift_model
      angular_size_model
      flux_model
      flux_density_model
      luminosity_model
      apparent_magnitude_model
      absolute_magnitude_model
      photometric_system_model
      color_index_model
      extinction_model
      spectral_model
      wavelength_frequency_model
      spectral_resolution_model
      equivalent_width_model
      temperature_model
      Wien_model
      Stefan_Boltzmann_model
      stellar_radius_model
      mass_model
      Kepler_orbit_model
      orbital_elements_model
      transit_model
      exoplanet_radial_velocity_model
      cosmological_distance_model
      Hubble_model
      surface_brightness_model
      solid_angle_model
      radio_model
      X_ray_gamma_model
      detector_model
      telescope_model
      atmospheric_seeing_model
      air_mass_model
      calibration_model
      relationships
      constraints
      measurement_model
      uncertainty_model
      reasoning_rules
      confidence_model
      update_model

    PURPOSE:
      deterministic_semantic_integrity_identifier

    RECOMPUTE_WHEN:
      ontology_definition_changes
      astronomical_quantity_model_changes
      coordinate_frame_or_epoch_changes
      distance_or_astrometric_model_changes
      photometric_or_spectral_model_changes
      orbital_or_cosmological_model_changes
      detector_or_calibration_model_changes
      time_system_changes
      measurement_model_changes
      constraint_model_changes
      reasoning_rule_changes
      unit_model_changes
  }

}

END FLOW