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)

João de Moraes Pereira discovered that the star's brightness varies, in 1893. It was given its variable star designation in 1921. [10] This is a semiregular variable of subtype SRb [3] with periods of 186 and 366 days due to radial pulsations. [7]

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. 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 [11] 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. [12]

Related Research Articles

<span class="mw-page-title-main">Eta Cassiopeiae</span> Binary star system in the constellation Cassiopeia

Eta Cassiopeiae is a binary star system in the northern constellation of Cassiopeia. Its binary nature was first discovered by William Herschel in August 1779. Based upon parallax measurements, the distance to this system is 19.42 light-years from the Sun. The two components are designated Eta Cassiopeiae A and B.

<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">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. It is a variable star that is occasionally bright enough to be seen by the naked eye under excellent observing conditions.

<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">50 Cassiopeiae</span> Star in the constellation Cassiopeia

50 Cassiopeiae is a white star in the northern constellation of Cassiopeia. In the past, it had been misidentified as a suspected nebula, and given the number NGC 771. The star is visible to the naked eye, having an apparent visual magnitude of +3.95. Based upon an annual parallax shift of 20.76 mas, it is located 157 light years away. It is moving closer, having a heliocentric radial velocity of −18 km/s, and will approach to within 82 ly in 1.879 million years.

<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, making it visible to the naked eye.

<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">Pi Cassiopeiae</span> Variable star in the constellation Cassiopeia

Pi Cassiopeiae, Latinized from π Cassiopeiae, is a close binary star system in the constellation Cassiopeia. It is visible to the naked eye with an apparent visual magnitude of +4.949. Based upon an annual parallax shift of 18.63 mas as seen from Earth, this system is located about 175 light years from the Sun.

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

Phi Cassiopeiae is a multiple star in the constellation Cassiopeia 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.

42 Cassiopeiae is a possible binary star system in the northern circumpolar constellation of Cassiopeia. It is visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of +5.18. The system is located approximately 291 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +7 km/s.

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

R Cassiopeiae is a variable star in the northern constellation of Cassiopeia. It is located approximately 574 light years distant from the Sun, but is drifting closer with a radial velocity of −23 km/s. This is a pulsating Mira-type variable star with a brightness varies from magnitude +4.4 down to +13.5 with a period of 433.6 days. At its maximum, R Cassiopeiae is visible to the naked eye as a faint, red-hued star.

<span class="mw-page-title-main">6 Cassiopeiae</span> Star in the constellation Cassiopeia

6 Cassiopeiae is a white hypergiant in the constellation Cassiopeia, and a small-amplitude variable star.

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

TZ Cassiopeiae(TZ Cas, HIP 117763, SAO 20912) is a variable star in the constellation Cassiopeia with an apparent magnitude of around +9 to +10. It is approximately 8,400 light-years away from Earth. The star is a red supergiant star with a spectral type of M3 and a temperature around 3,600 K.

69 Virginis is a single star in the zodiac constellation of Virgo, located about 259 light years away. It is visible to the naked eye as a faint orange-hued star with an apparent visual magnitude of 4.76, although it is a suspected variable that may range in magnitude from 4.75 down to 4.79. This object is moving closer to the Earth with a heliocentric radial velocity of −13 km/s. The light from this star is polarized due to intervening interstellar dust.

<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">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.

<span class="mw-page-title-main">WZ Doradus</span> Semiregular variable in Dorado

WZ Doradus is a solitary red-hued variable star located in the southern constellation Dorado. It has an average apparent magnitude of 5.21, making it faintly visible to the naked eye under ideal conditions. Gaia DR3 parallax measurements imply a distance of 580 light-years and it is currently receding with a heliocentric radial velocity of 19.3 km/s. At its current distance, WZ Doradus is diminished by two-tenths of a magnitude due to interstellar extinction and it has an absolute magnitude of −1.00.

References

  1. 1 2 3 4 5 6 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.
  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. ↑ Hartwig; Muller (January 1921). "Benennung von neu entdeckten veränderlichen Sternen". Astronomische Nachrichten. 212 (19): 353–374. Bibcode:1921AN....212..353.. doi:10.1002/asna.19202121902 . Retrieved 23 December 2024.
  11. ↑ 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.
  12. ↑ 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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