IM Pegasi
E817765
IM Pegasi is a nearby RS Canum Venaticorum-type binary star system in the constellation Pegasus, notable for its strong radio emissions and use as the guide star for the Gravity Probe B relativity experiment.
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
RS Canum Venaticorum variable star system
ⓘ
binary star system ⓘ radio star ⓘ |
| activityType | chromospherically active binary ⓘ |
| apparentMagnitudeV | ~5.7 ⓘ |
| belongsToClass | RS CVn binaries with strong magnetic activity ⓘ |
| catalogDesignation |
HD 216489
NERFINISHED
ⓘ
HIP 112997 NERFINISHED ⓘ HR 8703 NERFINISHED ⓘ |
| constellation | Pegasus NERFINISHED ⓘ |
| coordinateReferenceRole | astrometric reference source for Gravity Probe B ⓘ |
| declination | +16° 50′ (approx) ⓘ |
| distanceFromEarth |
~29 parsecs
ⓘ
~96 light-years ⓘ |
| emission |
X-ray emission
ⓘ
strong radio emission ⓘ |
| hemisphere | northern celestial hemisphere ⓘ |
| importanceInAstrophysics | benchmark RS CVn radio emitter ⓘ |
| importanceInRelativityTests | primary guide star for Gravity Probe B mission ⓘ |
| lightCurveBehavior | quasi-periodic variability ⓘ |
| luminosityClassPrimary | giant ⓘ |
| magneticActivity |
flaring
ⓘ
strong starspots ⓘ |
| massPrimary | >1 solar mass ⓘ |
| massSecondary | ~1 solar mass (approx) ⓘ |
| observedBy |
Hubble Space Telescope (astrometric context for GP-B)
NERFINISHED
ⓘ
Very Long Baseline Interferometry (VLBI) arrays NERFINISHED ⓘ |
| orbitalEccentricity | low ⓘ |
| orbitalPeriod | ~24.65 days ⓘ |
| parallax | ~34 milliarcseconds ⓘ |
| primaryStarEvolutionaryStage | evolved K-type giant GENERATED ⓘ |
| radioStructure | compact, variable radio source ⓘ |
| radiusPrimary | >10 solar radii (approx) ⓘ |
| rightAscension | 22h 53m 02s (approx) ⓘ |
| secondaryStarEvolutionaryStage | near main sequence ⓘ |
| spectralTypePrimary | K2III ⓘ |
| spectralTypeSecondary | G-type main-sequence star ⓘ |
| systemType | close binary ⓘ |
| usedAsGuideStarFor | Gravity Probe B NERFINISHED ⓘ |
| usedFor | high-precision astrometry ⓘ |
| usedInExperiment | test of general relativity with Gravity Probe B ⓘ |
| usedToMeasure |
frame-dragging effect
ⓘ
geodetic effect ⓘ |
| variabilityCause | starspots and rotation of active components ⓘ |
| variableStarDesignation | IM Peg NERFINISHED ⓘ |
| variableStarType | RS Canum Venaticorum NERFINISHED ⓘ |
| visibility | naked-eye star under good conditions ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
Gravity Probe B