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physical object > natural object > celestial body > collection of stars > star system > binary star > spectroscopic binary

spectroscopic binary
subject			fact

spectroscopic binary	has definition Star whose binary nature can be detected from the periodic Doppler shifts of their spectra, owing to their varying velocities in the line of sight. Double-lined spectroscopic binaries have two sets of spectral features, oscillating with opposite phases. Single-lined spectroscopic binaries have only one set of oscillating spectral lines, owing to the dimness of the secondary component. Spectroscopic binaries are typically of spectral type B, with almost circular orbits (whereas long-period M-type binaries have highly eccentric orbits).
	is a kind of binary star
binary star	has number of stars 2
	has orbital period
star system	has abundance half the stars in the solar neighborhood are members of star systems
star	has star surface temperature
	has spectral type
	has V magnitude
	has B magnitude
	has U magnitude
	has position on celestial sphere from the point of view of Earth
	has parallax from the point of view of Earth's orbit
	has proper motion
	has radiation at surface which is diffused out from the hotter core
	has energy source gravitational contraction and or fusion
	has energy production which takes place primarily within the core
	has surface density which depends on luminosity class
	has surface temperature greater than 1000 Kelvin
	has apparent magnitude
	has absolute magnitude
	has age
	has catalog star catalog
	has material hydrogen, helium
	has velocity determined from proper motion and radial velocity
	has mass greater than 0.08 the sun's mass
celestial body	has spectra
physical object	has location or center of gravity
	has angular momentum
	has momentum
	has temperature
	has volume
	has extent

Kinds of spectroscopic binary :

• double line spectroscopic binary (3 facts) - a spectroscopic binary in which periodic Doppler shift is detected in both components of the binary star each out of phase by 180 degrees
• Plaskett's star (6 facts) (HD 47129) - A very massive O-type giant with known anomalies in its spectrum. It is a spectroscopic binary in which mass exchange is occurring. Its spectrum can be interpreted to mean that each component has a mass of 75 M_sun.
• single line spectroscopic binary (1 kind, 13 facts) - a spectroscopic binary in which periodic Doppler shift is detected in only one component of the binary star
• Spica (17 facts) (alpha Vir, HR 5056) - A double-lined spectroscopic binary (B1.5 V, late B). Component A (10.9 M_sun) is a beta Cephei star which seems to be near core hydrogen exhaustion.
• Theta2 Orionis (8 facts) (2U 0525-06) - A spectroscopic binary tentatively identified with 2U 0525-06.

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