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physical object > natural object > celestial body > collection of stars > star system > binary star > close binary > eclipsing binary > Hercules X-1

Hercules X-1 (3U 1653+35)
subject			fact

Hercules X-1	has eclipse duration 0.24 days (in X-rays)
	is a part of Hercules
	has eccentricity e < 0.1
	has distance 5 kpc
	has synonym 3U 1653+35
	has orbital period 1.7 days
	has definition An X-ray pulsar, a member of an occulting binary system. The visible component has been identified as the blue variable HZ Herculis, whose spectrum varies from late A or early F to B. Her X- l has a pulsation period of 1.2378 seconds, presumably its rotation period, and exhibits a 35-day quasi-periodicity in the X-ray region (but not in the optical). It is probably a rotating neutron star in a circular orbit with a mass of about 0.7 Msun, which is accreting matter from HZ Her. The orbital period is stable, but the pulsation period is speeding up at a rate of about 1 part in 105 per year. The X-ray eclipse lasts 0.24 days.
	is an instance of X-ray pulsar
	is an instance of eclipsing binary
periodic variable	has period
pulsar	has acronym PSR
binary star	has number of stars 2
variable	has name designated with R, S, T, U, V, W, X, Y, or Z and the genitive of the latin constellation name RR, RS, RT, RU, RV, RW, RX, RY, or RZ and the genitive of the latin constellation name when the single letter designations are exhausted AA...AZ, BB...BZ, etc. (omitting J), which ends with QQ...QZ and the genitive of the latin constellation namewhen the RR...RZ designations are exhausted V 335, V 336, etc., when the double letter designations are exhausted
	has observational problem some difficulty in distinguishing between various kinds
	has observable variation time scale within a period of decades
	has light curve
	has optical brightness variation 0.2 magnitudes or greater
	has amplitude
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
massive compact halo object	is a part of halo
celestial body	has spectra
dark matter	is a part of dark halo
hypothetical particle	has acceptance status hypothetical
physical object	has location or center of gravity
	has angular momentum
	has momentum
	has temperature
	has volume
	has extent
particle	obeys uncertainty principle
	has frequency inversely proportional to the wavelength
	has wavelength inversely proportional to its momentum
	has charge

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