LZ Cephei

LZ Cephei

A light curve for LZ Cephei, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cepheus
Right ascension 22h 02m 04.57263s[2]
Declination +58° 00′ 01.3098″[2]
Apparent magnitude (V) 5.6[3]
Characteristics
Spectral type O 9III (primary) + ON 9.7V (secondary)[4]
Variable type Rotating ellipsoidal variable[5]
Astrometry
Proper motion (μ) RA: −3.096±0.061[2] mas/yr
Dec.: −2.611±0.054[2] mas/yr
Parallax (π)0.9070 ± 0.0525 mas[2]
Distance3,600 ± 200 ly
(1,100 ± 60 pc)
Orbit[4]
Period (P)3.070507 d
Eccentricity (e)0.0
Inclination (i)49±2.4°
Semi-amplitude (K1)
(primary)		88.72±1.02 km/s
Semi-amplitude (K2)
(secondary)		224.48±2.58 km/s
Details
Primary
Mass16.0[4] M☉
Radius11.7+3.3
−2.7[4] R☉
Luminosity79,000[3] L☉
Surface gravity (log g)3.71±0.02[3] cgs
Temperature32,000±1,000[4] K
Secondary
Mass6.5[4] M☉
Radius9.4+2.6
−2.2[4] R☉
Luminosity45,000[3] L☉
Surface gravity (log g)3.48±0.02[3] cgs
Temperature28,000±1,000[4] K
Other designations
14 Cephei, HD 209481, BD+57 2441, HIP 108772, HR 8406, SAO 33990[6]
Database references
SIMBADdata

LZ Cephei, also known by its Flamsteed designation 14 Cephei, is a star about 3,600 light years from the Earth, in the constellation Cepheus. Its apparent magnitude is 5.6, making it faintly visible to the naked eye of an observer far from city lights.[3] The star is a rotating ellipsoidal variable whose brightness, as measured by the Hipparcos satellite, varies between magnitude 5.52 and 5.61.[5]

LZ Cephei was discovered to be a binary star by William Edmund Harper in 1931.[7] The orbital elements were first calculated by Robert Methven Petrie in 1962.[7] It was discovered to be a variable star in 1972 by N. Kameswara Rao, using the Lick Observatory's 24 inch telescope.[8] The star was given the variable star designation LZ Cephei in 1973.[9] It was classified as an ellipsoidal variable by Hill et al. in 1976.[10]

A 2011 study of LZ Cephei concluded that the existing data are best explained if the system is a semi-detached binary with either the primary or secondary star nearly filling its Roche lobe. The secondary star, now less massive than the primary, was originally the more massive star, and matter has been transferred from the secondary to the primary.[4]

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference dr3 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference Harries1998 was invoked but never defined (see the help page).
  4. ^ a b c d e f g h i Cite error: The named reference Mahy2011 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Petrie1962 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Rao1972 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Kukarkin1973 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Hill1976 was invoked but never defined (see the help page).