U Vulpeculae

U Vulpeculae

A visual band light curve for U Vulpeculae, adapted from Kiss (1998)[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Vulpecula
Right ascension 19h 36m 37.7281s[2]
Declination 20° 19′ 58.5692″[2]
Apparent magnitude (V) 6.73 - 7.54[3]
Characteristics
Spectral type F6Iab-G2[4]
Variable type δ Cep[3]
Astrometry
Proper motion (μ) RA: 0.906±0.050[2] mas/yr
Dec.: −0.960±0.062[2] mas/yr
Parallax (π)1.0530 ± 0.0390 mas[2]
Distance3,100 ± 100 ly
(950 ± 40 pc)
Absolute magnitude (MV)-3.69[5]
Orbit[6]
Period (P)2,510 days
Eccentricity (e)0.675
Periastron epoch (T)2444800
Argument of periastron (ω)
(secondary)		353°
Semi-amplitude (K1)
(primary)		3.64 km/s
Details
Mass6.5[7] M☉
Radius60[7] R☉
Surface gravity (log g)1.75 - 1.85[8] cgs
Temperature5,655 - 5,965[8] K
Metallicity [Fe/H]0.09[9] dex
Age82[9] Myr
Other designations
BD+20° 4200, HD 185059, HIP 96458, HR 7458, SAO 87447[10]
Database references
SIMBADdata

U Vulpeculae is a variable and binary star in the constellation Vulpecula.

It is a classical Cepheid variable and its apparent magnitude ranges from 6.73 to 7.54 over a precise cycle of 7.99 days.[4] Its variable nature was discovered in 1898 at Potsdam Observatory by Gustav Müller and Paul Kempf.[11]

In 1991 a study of radial velocities showed that it U Vulpeculae is a spectroscopic binary and a full orbit with a period of 2510 days (6.9 years) was first calculated in 1996.[12][7] The secondary star is invisible and is only known from its effect on the motion of the primary.[6]

  1. ^ Cite error: The named reference Kiss was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference Gaia DR2 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference AAVSO was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference kovtyukh was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference groenewegen was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Imbert1996 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference andrievsky was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference marsakov was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Simbad was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Müller1898 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Szabados1991 was invoked but never defined (see the help page).