BlackHole

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Position and mass‐derived properties of black holes.

Entity["BlackHole",name] or

represents an entity of type "BlackHole".

[prop]

gives the value of a specified property.

[{prop1,…}]

gives the value of a list of properties.

[prop,{qualivali,…}]

gives the value of a specified property modified by qualifier rules quali->vali.

[Dated[prop,date]]

gives the value of a property associated with a particular date specification.

EntityClass["BlackHole",{propispeci,…}]

represents a class of entities with values of propi defined by speci.

Sample Entities

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Sample Entity Classes

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Properties

  • AlternateNamesalternate names
    Altitudealtitude
    AltitudeMaximumnext maximum altitude
    AltitudeTransitnext transit altitude
    AngularDiameterFromEarthangular diameter
    AngularRadiusFromEarthangular radius
    ApparentAltitudeapparent altitude
    Azimuthazimuth
    AzimuthRiseazimuth at rise
    AzimuthSetazimuth at set
    BooleanRiseabove the horizon
    Classesclasses
    Constellationconstellation
    DailyTimeAboveHorizondaily time above horizon
    Declinationdeclination
    DegreesOfFreedomdegrees of freedom
    DistanceFromEarthdistance from Earth
    DistanceFromSundistance from Sun
    EffectiveDensityeffective density
    EntityClassesentity classes
    EntityTypeListentity type list
    Entropyentropy
    EventHorizonAreaevent horizon area
    EventHorizonInteriorVolumeevent horizon interior volume
    EventHorizonSurfaceGravityevent horizon surface gravity
    GalacticLatitudegalactic latitude
    GalacticLongitudegalactic longitude
    GeocentricEclipticLatitudegeocentric ecliptic latitude
    GeocentricEclipticLongitudegeocentric ecliptic longitude
    GreenwichHourAngleGreenwich hour angle
    HeliocentricEclipticLatitudeheliocentric ecliptic latitude
    HeliocentricEclipticLongitudeheliocentric ecliptic longitude
    HelioCoordinatesheliocentric ecliptic XYZ coordinates
    Lifetimelifetime
    LocalHourAnglelocal hour angle
    Massmass
    MaximalAltitudeTimenext maximum altitude time
    Namename
    ObjectTypeobject type
    RelatedObjectsrelated objects
    RightAscensionright ascension
    RiseTimenext rise
    SchwarzschildRadiusSchwarzschild radius
    SetTimenext set
    SiderealHourAnglesidereal hour angle
    StellarEvolutionDiagramstellar evolution diagram
    SunElongationelongation from the Sun
    SystemMemberssystem members
    Temperaturetemperature
    TransitTimenext transit time
    ZenithAnglezenith angle

Details

  • "BlackHole" entities include black holes found in star systems throughout the Milky Way Galaxy, intermediate‐mass black holes and supermassive black holes found in the cores of galaxies.
  • "BlackHole" entity classes include groups based on mass, such as "supermassive" and "stellar‐mass".
  • Some properties are available for the "BlackHole" entity type as a whole and can be given using the form EntityValue["BlackHole",property]. Such properties include:
  • "Properties"the list of available properties
    "PropertyCanonicalNames"the standard names of available properties
    "SampleEntities"a sample list of available entities (typically of length 10)
    "SampleEntityClasses"a sample list of available entity classes (typically of length 10)
    "EntityCount"number of entities available
    "Entities"the list of available entities
    "EntityCanonicalNames"the standard names of available entities
    "EntityClasses"the list of available entity classes
    "EntityClassCanonicalNames"the standard names of available entity classes
    "PropertyClasses"the list of available property classes
    "PropertyClassCanonicalNames"the standard names of available property classes
    "PropertyCount"number of properties available
  • The following annotations can be used in the third argument of EntityValue["BlackHole",property,annotation]:
  • "Source"source information for the property
    "Date"the date associated with the entity-property value (if any)
    "EntityAssociation"an association of entities and entity-property values
    "PropertyAssociation"an association of properties and entity-property values
    "EntityPropertyAssociation"an association in which the specified entities are keys, and values are a nested association of properties and entity-property values
    "PropertyEntityAssociation"an association in which the specified properties are keys, and values are a nested association of entities and entity-property values
    "Dataset"a dataset in which the specified entities are keys, and values are an association of property names and entity-property values
  • The following annotations can be used in the second argument of EntityValue[property,annotation]:
  • "Qualifiers"the list of possible qualifiers for the property
    "QualifierValues"the list of possible values that can be given to each qualifier
    "DefaultQualifierValues"the list of default values for the property's qualifiers
    "Description"a brief textual description of the property
    "Definition"a detailed textual definition of the property
    "PhysicalQuantity"the physical quantity associated with the entity-property value
    "Unit"the unit associated with the entity-property value
  • A qualifier value of Automatic indicates that an applicable format of values can be used; e.g. for the "Date" qualifier, this includes a proper date or date span.

范例

打开所有单元关闭所有单元

基本范例  (6)

Use for discovery:

Find the distance to a black hole:

Retrieve a dataset of all available properties for an entity:

Find the three nearest black holes:

Find the equatorial coordinates of a black hole:

Find the current sky position of a black hole from your location:

Scope  (4)

Implicit Entity Classes  (1)

Represent the three most massive black holes:

Get a list of the black holes:

Property Classes  (1)

Represent equatorial coordinate properties associated with black holes:

Get a list of available property classes for black holes:

Find the list of properties included in a property class:

Obtain the property values for the properties in a property class for an entity:

Qualifiers  (2)

Some properties accept qualifiers:

The "Location" qualifier, which specifies the location of the observer, can accept an explicit GeoPosition, location-based Entity objects or queries that evaluate to one of these:

Dates  (1)

Date qualifiers can accept an explicit DateObject or queries that evaluate to a DateObject:

Date qualifiers can also be specified using Dated: