WZ Cassiopeiae

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WZ Cassiopeiae
WZ Cassiopeiae.jpg
WZ Cassiopeiae in optical light
Observation data
Epoch J2000       Equinox J2000
Constellation Cassiopeia
Right ascension 00h 01m 15.85680s [1]
Declination +60° 21′ 19.0259″ [1]
Apparent magnitude  (V)7.04 [2] (6.3 – 8.8) [3]
Characteristics
Spectral type C-N7 III: C2 2 Li 10 [4]
U−B color index +4.29 [5]
B−V color index +2.835±0.040 [2]
Variable type SRb [3]
Astrometry
Radial velocity (Rv)−34.0±2 [6]  km/s
Proper motion (μ)RA: +10.7693 [1]   mas/yr
Dec.: −5.672 [1]   mas/yr
Parallax (π)2.1227 ± 0.0297  mas [1]
Distance 1,540 ± 20  ly
(471 ± 7  pc)
Details
Radius ~600 [7]   R☉
Luminosity 12,400 [8]   L☉
Temperature 3,095 [8]   K
Other designations
WZ Cas, BD+59°2810, HD  224855, HIP  99, SAO  21002 [9]
Database references
SIMBAD data

WZ Cassiopeiae (WZ Cas) is a deep red hued star in the northern constellation of Cassiopeia. It is a variable star with a magnitude that ranges from 6.3 down to 8.8, [3] placing it near the limit of naked eye visibility at peak magnitude. The estimated distance to this star, as determined from its annual parallax shift of 2.1  mas , [1] is about 1,540  light years. It is moving closer to the Earth with a heliocentric radial velocity of −34 km/s. [6]

A visual band light curve for WZ Cassiopeiae, adapted from Lebzelter et al. (2005) WZCasLightCurve.png
A visual band light curve for WZ Cassiopeiae, adapted from Lebzelter et al. (2005)

This is an aging carbon star on the asymptotic giant branch. [7] Keenan (1993) assigned it a classification of C-N7 III: C2 2 Li 10, which indicates it is of the N star subtype in the revised Morgan–Keenan system, with a C2 strength index of 2 (a measure of the excess of carbon over oxygen) and an anomalously strong line of lithium at 6707  Å. [4] It is losing mass at the rate of 6.5×10−9 M☉ yr−1, which is on the low side for a star of this type. This is a semiregular variable of subtype SRb [3] with periods of 186 and 366 days due to radial pulsations. [7] It has expanded to around 600 times the Sun's radius and is radiating 12,400 times the Sun's luminosity [8] from its photosphere at a relatively cool [10] effective temperature of 3,095 K. [8]

A magnitude 8.4 B-type visual companion, designated HD 224869, is located at an angular separation of 58″ . The difference in the radial velocities for the two stars – 20 km/s – is too large for them to be dynamically associated. [11]

Related Research Articles

<span class="mw-page-title-main">Alpha Cassiopeiae</span> Star in the constellation Cassiopeia

Alpha Cassiopeiae or α Cassiopeiae, also named Schedar, is a second-magnitude star in the northern constellation of Cassiopeia. Though listed as the "alpha star" by Johann Bayer, α Cas's visual brightness closely matches the 'beta' (β) star in the constellation and it may appear marginally brighter or dimmer, depending on which passband is used. However, recent calculations from NASA's WISE telescope confirm that α Cas is the brightest in Cassiopeia, with an apparent magnitude of 2.240. Its absolute magnitude is 18 times greater than β Cas, and it is located over four times farther away from the Sun.

<span class="mw-page-title-main">Rho Cassiopeiae</span> Yellow hypergiant star in the constellation Cassiopeia

Rho Cassiopeiae is a yellow hypergiant star in the constellation Cassiopeia. It is about 3,400 light-years (1,000 pc) from Earth, yet can still be seen by the naked eye as it is over 300,000 times brighter than the Sun. On average it has an absolute magnitude of −9.5, making it visually one of the most luminous stars known. Its diameter measures between 636 and 981 times that of the Sun, approximately 1,125,000,000 kilometers, or almost four times the size of Earth's orbit.

<span class="mw-page-title-main">Delta Scuti</span> Star in the constellation Scutum

Delta Scuti, Latinized from δ Scuti, is a variable star in the southern constellation Scutum. With an apparent visual magnitude that fluctuates around 4.72, it is the fifth-brightest star in this small and otherwise undistinguished constellation. Analysis of the parallax measurements place this star at a distance of about 199 light-years from Earth. It is drifting closer with a radial velocity of −45 km/s.

<span class="mw-page-title-main">UU Aurigae</span> Star in the constellation of Auriga

UU Aurigae is a carbon star in the constellation Auriga. It is approximately 341 parsecs from Earth.

27 Cancri is a single star in the zodiac constellation of Cancer, located around 990 light-years away from the Sun. It is visible to the naked eye as a faint, red-hued star with a typical apparent visual magnitude of around +5.56. The star is moving closer to the Earth with a heliocentric radial velocity of −8.3 km/s. It is a member of the Arcturus stream, a group of stars with high proper motion and metal-poor properties thought to be the remnants of a small galaxy consumed by the Milky Way.

<span class="mw-page-title-main">Mu Cassiopeiae</span>

Mu Cassiopeiae, Latinized from μ Cassiopeiae, is a binary star system in the constellation Cassiopeia. This system shares the name Marfak with Theta Cassiopeiae, and the name was from Al Marfik or Al Mirfaq (المرفق), meaning "the elbow". It is dimly visible to the naked eye as a point of light with an apparent visual magnitude of 5.16. The system is located at a distance of 25 light years from the Sun based on parallax, and is moving closer with a high radial velocity of −98 km/s. This star will move into the constellation Perseus around 5200 AD.

<span class="mw-page-title-main">20 Canum Venaticorum</span> Star in the constellation Canes Venatici

20 Canum Venaticorum is a single variable star in the northern constellation of Canes Venatici, located 238 light years from the Sun. This object has the variable star designation AO Canum Venaticorum; 20 Canum Venaticorum is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with a baseline apparent visual magnitude of +4.72. The star is moving further from the Earth with a heliocentric radial velocity of +9 km/s. Eggen (1971) listed this star as a member of the Hyades Stream.

<span class="mw-page-title-main">Kappa Cassiopeiae</span> Star in the constellation Cassiopeia

Kappa Cassiopeiae is a star in the constellation Cassiopeia.

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

Sigma Cassiopeiae is a binary star in the constellation Cassiopeia. It is 1,200 to 1,400 light years from Earth and has a combined apparent magnitude of +4.88.

<span class="mw-page-title-main">Tau Cassiopeiae</span> K-type giant star in the constellation Cassiopeia

Tau Cassiopeiae is a solitary, orange hued star in the northern constellation of Cassiopeia. It is bright enough to be seen with the naked eye, having an apparent visual magnitude of +4.86. Based upon an annual parallax shift of 18.75 mas as seen from Earth, this system is located about 174 light years from the Sun.

<span class="mw-page-title-main">Phi Cassiopeiae</span> Star in the constellation Cassiopeia

Phi Cassiopeiae is a star in the constellation Cassiopeia. φ Cassiopeiae is a multiple star with a combined apparent magnitude of +4.95. The two brightest components are A and C, sometimes called φ1 and φ2 Cas. φ Cas A is an F0 bright supergiant of magnitude 4.95 and φ Cas C is a 7.08 magnitude B6 supergiant at 134".

<span class="mw-page-title-main">4 Cassiopeiae</span> Star in the constellation Cassiopeia

4 Cassiopeiae is a red giant in the northern constellation of Cassiopeia, located approximately 790 light-years away from the Sun. It is visible to the naked eye as a faint, red-hued star with a baseline apparent visual magnitude of 4.96. At the distance of this system, its visual magnitude is diminished by an extinction of 0.56 due to interstellar dust. This system is moving closer to the Earth with a heliocentric radial velocity of −39 km/s.

<span class="mw-page-title-main">HD 32188</span> Star in the constellation Auriga

HD 32188 is suspected variable star in the northern constellation of Auriga, and is positioned roughly in between Eta and Zeta Aurigae. It has a white hue and is just barely visible to the naked eye with an apparent visual magnitude that fluctuates around 6.08. The distance to this star is approximately 3,000 light years, based on parallax. It has an absolute magnitude of −2.87.

<span class="mw-page-title-main">SU Andromedae</span> Star in the constellation Andromeda

SU Andromedae is a carbon star in the constellation of Andromeda. It is a variable star classified as a slow irregular pulsating supergiant, and varies from an apparent visual magnitude of 8.5 at minimum brightness to a magnitude of 8.0 at maximum brightness with no clear period.

<span class="mw-page-title-main">89 Herculis</span> Star in the constellation Hercules

89 Herculis is a binary star system located about 4,700 light years away from the Sun in the northern constellation of Hercules. It is visible to the naked eye as a faint, fifth magnitude star. The system is moving closer to the Earth with a heliocentric radial velocity of −28.5 km/s.

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

U Camelopardalis is a semiregular variable star in the constellation Camelopardalis. Based on parallax measurements made by the Hipparcos spacecraft, it is located about 3,000 light-years away from the Earth. Its apparent visual magnitude is about 8, which is dim enough that it cannot be seen with the unaided eye.

<span class="mw-page-title-main">RR Ursae Minoris</span> Star in the constellation Ursa Minor

RR Ursae Minoris, abbreviated RR UMi, is a binary star system in the northern circumpolar constellation of Ursa Minor. It can be viewed with the naked eye, typically having an apparent visual magnitude of around 4.710. Based upon an annual parallax shift of 10.0 mas as seen from Earth's orbit, it is located 330 light years away. The system is moving further from the Sun with a heliocentric radial velocity of +6 km/s.

<span class="mw-page-title-main">X Cancri</span> Variable star in the constellation Cancer

X Cancri is a variable star in the northern constellation of Cancer. It has a red hue and is visible to the naked eye at its brightest. The distance to this object is approximately 1,860 light years based on parallax measurements, but is drifting closer with a radial velocity of −5 km/s. It lies very close to the ecliptic and so is subject to lunar occultations.

<span class="mw-page-title-main">Y Lyncis</span> Variable star in the constellation Lynx

Y Lyncis is a semiregular variable star in the constellation Lynx. It is an asymptotic giant branch star of spectral type M6S, with a luminosity class of Ib, indicating a supergiant luminosity. It is around 1,160 light years away.

<span class="mw-page-title-main">X Cygni</span> Variable star in the constellation Cygnus

X Cygni is a variable star in the northern constellation of Cygnus, abbreviated X Cyg. This is a Delta Cephei variable that ranges in brightness from an apparent visual magnitude of 5.85 down to 6.91 with a period of 16.386332 days. At it brightest, this star is dimly visible to the naked eye. The distance to this star is approximately 628 light years based on parallax measurements. It is drifting further away with a radial velocity of 8.1 km/s. This star is a likely member of the open cluster Ruprecht 173.

References

  1. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia Collaboration) (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics . arXiv: 2208.00211 . doi: 10.1051/0004-6361/202243940 . Gaia DR3 record for this source at VizieR.
  2. 1 2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID   119257644.
  3. 1 2 3 4 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.
  4. 1 2 Keenan, P. C. (1993). "Revised MK Spectral Classification of the Red Carbon Stars". Publications of the Astronomical Society of the Pacific . 105: 905. Bibcode:1993PASP..105..905K. doi: 10.1086/133252 .
  5. ↑ Mendoza v., Eugenio E.; Johnson, Harold L. (1965). "Multicolor Photometry of Carbon Stars". The Astrophysical Journal. 141: 161. Bibcode:1965ApJ...141..161M. doi: 10.1086/148097 .
  6. 1 2 Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington: 0. Bibcode:1953GCRV..C......0W.
  7. 1 2 3 4 Lebzelter, T.; et al. (September 2005). "WZ Cas - variability on multiple time-scales". Astronomy and Astrophysics. 440 (1): 295–303. Bibcode:2005A&A...440..295L. doi: 10.1051/0004-6361:20053076 .
  8. 1 2 3 4 Bergeat, J; Knapik, A; Rutily, B (2002). "Carbon-rich giants in the HR diagram and their luminosity function". Astronomy & Astrophysics. 390 (3): 967–986. Bibcode:2002A&A...390..967B. doi: 10.1051/0004-6361:20020525 .
  9. ↑ "WZ Cas". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 27 August 2018.
  10. ↑ Alksnis, O.; Zacs, L. (May 1994). "The Violet Opacity in the Red Peculiar Stars (II). Spectral Analysis of the Cool Carbon Stars WZ CAS and V CYG". Astrophysics and Space Science. 215 (1): 73–82. Bibcode:1994Ap&SS.215...73A. doi:10.1007/BF00627461. S2CID   117515681.
  11. ↑ Herbig, George H. (June 1955). "HD 224869: an Optical Companion to WZ Cassiopeiae". Publications of the Astronomical Society of the Pacific. 67 (396): 181. Bibcode:1955PASP...67..181H. doi: 10.1086/126798 .
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