[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["Star",{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
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AbsoluteMagnitude absolute magnitude AbsoluteMagnitudeBolometric absolute bolometric magnitude Age age AlphanumericName alphanumeric name AlternateNames alternate names Altitude altitude AltitudeTransit next transit altitude AngularDiameterFromEarth angular diameter AngularRadiusFromEarth angular radius Apoapsis largest distance from orbit center ApparentAltitude apparent altitude ApparentMagnitude apparent magnitude Azimuth azimuth AzimuthRise azimuth at rise AzimuthSet azimuth at set BayerName Bayer name BayerStandardName Bayer standard name BooleanRise above the horizon BVColorIndex BV color index Classes classes Color color Component component Constellation constellation DailyTimeAboveHorizon daily time above horizon Declination declination Density mean density Diameter average diameter DistanceFromEarth distance from Earth DistanceFromSun distance from Sun DurchmusterungName Durchmusterung name DurchmusterungStandardName Durchmusterung standard name Eccentricity orbital eccentricity EffectiveTemperature effective temperature EntityClasses entity classes EntityTypeList entity type list EquatorialDiameter equatorial diameter EquatorialRadius equatorial radius EscapeVelocity escape velocity FlamsteedName Flamsteed name FlamsteedStandardName Flamsteed standard name GalacticLatitude galactic latitude GalacticLongitude galactic longitude GeocentricEclipticLatitude geocentric ecliptic latitude GeocentricEclipticLongitude geocentric ecliptic longitude GlieseName Gliese catalog designation GlieseStandardName Gliese standard name Glyph astrological symbol GravitationalConstantMassProduct gravitational constant mass product Gravity gravity GreenwichHourAngle Greenwich hour angle HDName HD catalog name HDNumber HD catalog number HeliocentricEclipticLatitude heliocentric ecliptic latitude HeliocentricEclipticLongitude heliocentric ecliptic longitude HelioCoordinates heliocentric XYZ coordinates HipparcosName Hipparcos name HipparcosNumber Hipparcos number HRName HR catalog name HRNumber HR catalog number ICNumber IC number Image image LifetimeEntropy lifetime entropy LocalHourAngle local hour angle Luminosity luminosity LuminosityMassRateEquivalent luminosity mass rate equivalent MainSequenceLifetime main sequence lifetime MajorAxis orbital major axis Mass mass MaximalAltitudeTime next maximum altitude time MaximumAbsoluteMagnitude maximum absolute magnitude MaximumApparentMagnitude maximum apparent magnitude Metallicity metallicity MinimumAbsoluteMagnitude minimum absolute magnitude MinimumApparentMagnitude minimum apparent magnitude MomentOfInertia rotational moment of inertia MultipleSystemMember member of a multiple star system Name name NGCNumber NGC number ObjectType object type Oblateness oblateness Obliquity obliquity OrbitalAngularMomentum orbital angular momentum OrbitCenter orbit center OrbitPeriod orbital period Parallax parallax Periapsis smallest distance from orbit center PolarDiameter polar diameter PolarRadius polar radius PositionAngle position angle ProperMotion proper motion ProperMotionDeclination proper motion declination ProperMotionRightAscension proper motion right ascension RadialVelocity radial velocity Radius average radius RightAscension right ascension RiseTime next rise RotationalAngularMomentum rotational angular momentum RotationPeriod rotation period SAOName SAO catalog name SAONumber SAO catalog number Satellites known satellites SemimajorAxis orbital semimajor axis Separation separation SetTime next set Shape shape SiderealHourAngle sidereal hour angle SpectralClass spectral class SpectralClassList spectral class list StarDistanceTimeSeries distance from Earth time series StarEndState stellar end state StarType star type StationaryOrbitRadius stationary orbit radius StationaryOrbitSpeed stationary orbit speed StellarEvolutionDiagram stellar evolution diagram SunElongation elongation from the Sun SurfaceArea surface area SystemMembers system members TransitTime next transit time TychoNumber Tycho number VariablePeriod variability period VariableStarName variable star name VariableStarType variable star type Volume volume WDSIdentifier WDS identifier ZenithAngle zenith angle
Details
- "Star" entities include a large collection of stellar objects from a variety of catalogs, including subsets of the Yale Bright Star Catalog, the Hipparcos Catalogue, the Henry Draper Catalogue and the Gliese Catalogue.
- "Star" entity classes include a large variety of groups based on aspects such as spectral types, chemical compositions, variable star types, constellation membership and catalog membership.
- Some properties are available for the "Star" entity type as a whole and can be given using the form EntityValue["Star",property]. Such properties include:
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"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["Star",property,annotation]:
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"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]:
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"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.
Examples
open allclose allBasic Examples (8)
for discovery:Scope (16)
The 15 brightest stars as seen from Earth:
The constellations for the 10 brightest stars:
Distance from Earth to Sirius:
Spectral class information in list form:
Henry Draper Memorial Catalogue number for Sirius:
Give the individual stars that form Alpha Centauri:
Give the name of Tau Ceti, including Greek letters:
Ten brightest supergiants as seen from Earth:
The number of available supergiants:
The 10 brightest class-O stars:
The 10 brightest Wolf–Rayet stars:
Implicit Entity Classes (1)
Property Classes (1)
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:
Applications (10)
Plot the right ascension and declination of the 100 brightest stars, with tooltips for their names:
The corresponding picture for the 100 nearest stars:
Rank plot of absolute magnitudes of the 100 nearest stars:
Rank plot of absolute magnitudes of the 100 brightest stars:
Distribution of basic spectral classes for the 100 brightest stars:
Distribution for the 100 nearest stars:
Rank plot of the distances to the 100 nearest stars:
Differences between successive distances:
Get the correct color and simulate lighting for a star:
The colors of stars are an indication of their temperatures:
The habitable zone of an exoplanet is an ambiguous concept with no agreed-upon definition. There are several ways to go about determining what you might interpret as the habitable zone. All methods have a relation to their host star.
One way of determining the habitable zone is described in Whitmire, D. and Reynolds, R., "Circumstellar Habitable Zones: Astronomical Considerations," in Doyle, L. (ed.), Circumstellar Habitable Zones, Proceedings of the First International Conference, Travis House Publications, 1996: 117–142. This method allows you to determine an inner and outer radius of the habitable zone around a star:
Relations to Other Entity Types (1)
Stars are orbited by entities of type "Planet" or "Exoplanet":
Possible Issues (1)
StarData combines star catalogs that select stars in different ways:
Star Source Information