double star
Two orbiting stars
A double star is a pair of stars that appear close together in the sky.
Some are binary stars—genuinely orbiting each other.
Others are optical doubles, unrelated stars that happen to lie along the same line of sight from Earth.
Astronomers distinguish the two through careful measurement of distance and motion: The telescope revealed Albireo to be a striking double star, one gold and one blue.
Numeration with two values
- barycenterMutual orbit point
- parallaxPosition change from different vantages
- magnitudeSize or scale
- separationState of being apart
Instrument magnifying faraway objects
- eyepieceLens you look through
- apertureAdjustable optical inlet
- splitSeparation into parts
- PolarisCelestial north marker
Castor · Alpha Centauri · binoculars · mount · tracking · magnification · field of view · amateur astronomy
Mutual mass attraction
- orbital mechanicsScience of celestial motion
- massQuantity of matter
- luminosityIntrinsic brightness of source
- main sequenceStable stellar burning phase
red giant · white dwarf · fusion · accretion · angular momentum · eccentricity · velocity · perturbation
binary system
Numeration with two values
- barycenterMutual orbit point
- parallaxPosition change from different vantages
- magnitudeSize or scale
telescope
Instrument magnifying faraway objects
Polaris · Castor · Alpha Centauri · binoculars · mount · tracking · magnification · field of view · amateur astronomy · catalog
gravity
Mutual mass attraction
- orbital mechanicsScience of celestial motion
- massQuantity of matter
- luminosityIntrinsic brightness of source
main sequence · red giant · white dwarf · fusion · accretion · angular momentum · eccentricity · velocity · perturbation · tidal forces
- astronomymoon, sun, planet, planets, telescope
- stargazingtelescope, stargazing guides, night sky, constellation, telescopes
- star shapesasterisk, pentagram, starburst, sparkle, sheriff badge
- starsSirius, Polaris, sol, sun, Vega
- constellation featurenebula, asterism, belt, dipper, cross pattern
- Binary Starsbarycenter