LZ Cephei

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LZ Cephei
LZCepLightCurve.png
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]
Distance 3,600 ± 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
Mass 16.0 [4]   M
Radius 11.7+3.3
−2.7
[4]   R
Luminosity 79,000 [3]   L
Surface gravity (log g)3.71±0.02 [3]   cgs
Temperature 32,000±1,000 [4]   K
Secondary
Mass 6.5 [4]   M
Radius 9.4+2.6
−2.2
[4]   R
Luminosity45,000 [3]   L
Surface gravity (log g)3.48±0.02 [3]   cgs
Temperature 28,000±1,000 [4]   K
Other designations
14 Cephei, HD  209481, BD+57 2441, HIP  108772, HR  8406, SAO  33990 [6]
Database references
SIMBAD data

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]

Related Research Articles

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<span class="mw-page-title-main">9 Aurigae</span> Multiple star system in the constellation Auriga

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<span class="mw-page-title-main">Sigma Puppis</span> Star in the constellation Puppis

Sigma Puppis, Latinized from σ Puppis, is a binary star system in the southern constellation Puppis. It has an apparent visual magnitude of 3.25, which is bright enough to be visible to the naked eye at night from the Southern Hemisphere. Through a telescope, it appears as a bright, orange-hued star with a nearby white companion. Parallax measurements indicate this star is located at a distance of about 192 light-years from Earth.

<span class="mw-page-title-main">VV Cephei</span> Binary star in the constellation Cepheus

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V354 Cephei is a red supergiant star located within the Milky Way. It is an irregular variable located over 13,000 light-years away from the Sun. It has an estimated radius of 1,139 solar radii. If it were placed in the center of the Solar System, it would extend to between the orbits of Mars and Jupiter.

Theta<sup>2</sup> Crucis Star in the constellation Crux

Theta2 Crucis, Latinized from θ2 Crucis, is a spectroscopic binary star in the constellation Crux. This pair of stars complete an orbit every 3.4280 days and they have a low orbital eccentricity that is close to 0.0. Theta2 Crucis is located at about 690 light-years from the Sun.

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<span class="mw-page-title-main">W Cephei</span> Variable star in the constellation Cepheus

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<span class="mw-page-title-main">HD 37756</span> Binary star system in the constellation Orion

HD 37756 is a binary star system in the equatorial constellation of Orion, positioned less than a degree to the north of the bright star Alnitak. It has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.95. The system is located at a distance of approximately 900 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +26 km/s. It is a member of the OB1b subgroup of the Orion OB1 association.

<span class="mw-page-title-main">QZ Puppis</span> Star in the constellation Puppis

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<span class="mw-page-title-main">16 Lacertae</span> Triple star system in the constellation Lacerta

16 Lacertae is a triple star system in the northern constellation of Lacerta, located about 1,580 light years from the Sun. It has the variable star designation EN Lacertae; 16 Lacertae is the Flamsteed designation. This system is visible to the naked eye as a faint blue-white hued star with a maximum apparent visual magnitude of +5.587. It is moving closer to the Earth with a heliocentric radial velocity of –12 km/s.

Psi<sup>2</sup> Orionis Spectroscopic binary system in the constellation of Orion

Psi2 Orionis a binary star system in the equatorial constellation of Orion. It has an apparent visual magnitude of 4.6, indicating that it is visible to the naked eye. Based upon an annual parallax shift of 2.87 mass, it is roughly 1,100 light years distant from the Sun.

<span class="mw-page-title-main">12 Lacertae</span> Star in the constellation Lacerta

12 Lacertae is a wide binary star system in the northern constellation of Lacerta, located roughly 1,260 light years away from the Sun based on parallax. It is visible to the naked eye as a dim, blue-white hued point of light with a baseline apparent visual magnitude of 5.23. The system is drifting closer to the Earth with a mean heliocentric radial velocity of –12.5. It is a probable member of the I Lacertae OB association.

<span class="mw-page-title-main">DH Cephei</span> Binary star system in the constellation Cepheus

DH Cephei is a variable binary star system in the northern circumpolar constellation of Cepheus, positioned about two degrees to the east of the star system Delta Cephei. With an apparent visual magnitude of 8.61, it is too faint to be visible without a telescope. Based on parallax measurements, this system is located at a distance of approximately 9.6 kilolight-years from the Sun. At present it is moving closer to the Earth with a radial velocity of −33 km/s.

<span class="mw-page-title-main">HD 159176</span> Variable star in the constellation Scorpius

HD 159176, also known as Boss 4444 and V1036 Scorpii, is a variable star about 2,800 light years from the Earth, in the constellation Scorpius. It is a 5th magnitude star, so it should be visible to the naked eye of an observer far from city lights. HD 159176 is the brightest star in the young open cluster NGC 6383. It is a binary star composed of two nearly identical O stars in a circular orbit.

<span class="mw-page-title-main">V2052 Ophiuchi</span> Variable star in the constellation Ophiuchus

V2052 Ophiuchi, also known as HR 6684, is a star about 920 light years from Earth in the constellation Ophiuchus. It is a 5th-magnitude star, making it faintly visible to the naked eye of an observer far from city lights. V2052 Ophiuchi is a Beta Cephei variable star, varying slightly in brightness from magnitude 5.81 to 5.84 over a period of about 3.4 hours.

<span class="mw-page-title-main">HD 149404</span> Variable star in the constellation Scorpius

HD 149404, also known as HR 6164 and V918 Scorpii, is a star about 4,300 light years from the Earth, in the constellation Scorpius. It is a 5th magnitude star, so it will be faintly visible to the naked eye of an observer far from city lights. It is a rotating ellipsoidal variable, a binary star for which the two stars' combined brightness varies slightly, from magnitude 5.42 to 5.50, during their 9.8 day orbital period. It is one of the brightest members of the Ara OB1 association, which has the open cluster NGC 6193 at its center.

References

  1. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 14 January 2023.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 4 5 6 Harries, T. J.; Hilditch, R. W.; Hill, G. (April 1998). "Interacting OB star binaries: LZ Cep, SZ Cam and IU AUR". Monthly Notices of the Royal Astronomical Society. 295 (2): 386–396. Bibcode:1998MNRAS.295..386H. doi: 10.1046/j.1365-8711.1998.01340.x .
  4. 1 2 3 4 5 6 7 8 9 Mahy, L.; Martins, F.; Machado, C.; Donati, J. F.; Bouret, J. C. (September 2011). "The two components of the evolved massive binary LZ Cephei. Testing the effects of binarity on stellar evolution". Astronomy & Astrophysics. 533. arXiv: 1106.6162 . Bibcode:2011A&A...533A...9M. doi: 10.1051/0004-6361/201116993 .
  5. 1 2 Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80. Bibcode:2017ARep...61...80S. doi: 10.1134/S1063772917010085 . S2CID   125853869.
  6. "14 Cep -- Spectroscopic Binary". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2023-01-14.
  7. 1 2 Petrie, R. M. (May 1962). "The O-type spectroscopic binary 14 Cephei". Publications of the Dominion Astrophysical Observatory Victoria. 12: 111–116. Bibcode: 1962PDAO...12..111P .
  8. Kameswara Rao, N. (August 1972). "Light Variations of Three Spectroscopic Binaries". Publications of the Astronomical Society of the Pacific. 84 (500): 563–565. Bibcode:1972PASP...84..563K. doi: 10.1086/129332 .
  9. Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P. (October 1973). "59th Name-List of Variable Stars". Information Bulletin on Variable Stars. 834 (1): 1. Bibcode: 1973IBVS..834....1K .
  10. Hill, G.; Hilditch, R. W.; Pfannenschmidt, E. L. (January 1976). "Photoelectric measures of variable stars observed at Mt. Kobau (1970 - 73)". Publications of the Dominion Astrophysical Observatory Victoria. 15: 1–35. Bibcode: 1976PDAO...15....1H .