Astronomy:WZ Doradus

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Short description: Semiregular variable in Dorado
WZ Doradus
Location of WZ Doradus on the map (circled)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Dorado
Right ascension  05h 07m 34.02686s[1]
Declination −63° 23′ 58.8474″[1]
Apparent magnitude (V) 5.20 - 5.32[2]
Characteristics
Evolutionary stage AGB[3]
Spectral type M3 III[4]
U−B color index +1.85[5]
B−V color index +1.65[5]
Variable type SRb[2]
Astrometry
Radial velocity (Rv)19.3±2.8[6] km/s
Proper motion (μ) RA: +13.210[1] mas/yr
Dec.: −44.813[1] mas/yr
Parallax (π)5.6282 ± 0.1116[1] mas
Distance580 ± 10 ly
(178 ± 4 pc)
Absolute magnitude (MV)−1.00[7]
Details
Mass1.4[8] M☉
Radius88.3+6.6−10.0[9] R☉
Luminosity1,248±47[9] L☉
Surface gravity (log g)0.50[10] cgs
Temperature3,603±125[10] K
Other designations
WZ Dor, CD−63°188, CPD−63°420, FK5 2389, GC 6314, HD 33684, HIP 23840, HR 1695, SAO 249198[11]
Database references
SIMBADdata

WZ Doradus (HD 33684; HR 1695; 21 G. Doradus) is a solitary red-hued variable star[12] located in the southern constellation Dorado. It has an average apparent magnitude of 5.21,[13] making it faintly visible to the naked eye under ideal conditions. Gaia DR3 parallax measurements imply a distance of 580 light-years[1] and it is currently receding with a heliocentric radial velocity of 19.3 km/s.[6] 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.[7]

HD 33684 was first observed to vary in brightness by astronomer P. M. Corben in 1971.[14] It was said to have an amplitude of 0.18 magnitudes. A year later, HD 33684 was given the variable star designation WZ Doradus.[15] It was again observed in 1973 by Olin J. Eggen and he noticed that it varied within 40 days.[16] A 1998 survey found no strong emissions indicating dust around the star.[17] Another survey also found no technetium in its spectrum.[18] WZ Doradus is a semiregular variable of subtype SRb that varies between 5.2 and 5.32 within an average period of 40 days.[2] Tabur et al. (2009) found two periods for the star after it was widely believed to only have one period.[19]

WZ Doradus variability periods[19]
Amplitude (mag) Period (days)
0.042 26.0
0.026 44.6
A light curve for WZ Doradus, plotted from data published by Tabur et al.[19]

WZ Doradus has a stellar classification of M3 III,[4] indicating that it is an evolved red giant. It is currently on the asymptotic giant branch,[3] generating energy via the fusion of hydrogen and helium shells around an inert carbon core. As a result of its evolved state, it has expanded to 88.3 times the radius of the Sun[9] and it now radiates 1,248 times the luminosity of the Sun[9] from its enlarged photosphere at an effective temperature of 3,603 K.[10]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports 61 (1): 80–88. doi:10.1134/S1063772917010085. ISSN 1063-7729. Bibcode: 2017ARep...61...80S. 
  3. ↑ 3.0 3.1 Eggen, Olin J. (July 1992). "Asymptotic giant branch stars near the sun". The Astronomical Journal 104: 275. doi:10.1086/116239. ISSN 0004-6256. Bibcode: 1992AJ....104..275E. 
  4. ↑ 4.0 4.1 Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars: Declinations −90° to −53°. 1. Bibcode: 1975mcts.book.....H. 
  5. ↑ 5.0 5.1 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode: 1986EgUBV........0M 
  6. ↑ 6.0 6.1 Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. ISSN 1063-7737. Bibcode: 2006AstL...32..759G. 
  7. ↑ 7.0 7.1 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode: 2012AstL...38..331A. 
  8. ↑ Kervella, Pierre et al. (March 2019). "Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly". Astronomy & Astrophysics 623: 23. doi:10.1051/0004-6361/201834371. A72. Bibcode: 2019A&A...623A..72K. 
  9. ↑ 9.0 9.1 9.2 9.3 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  10. ↑ 10.0 10.1 10.2 McDonald, I.; Zijlstra, A. A.; Watson, R. A. (15 June 2017). "Fundamental parameters and infrared excesses of Tycho–Gaia stars". Monthly Notices of the Royal Astronomical Society 471 (1): 770–791. doi:10.1093/mnras/stx1433. ISSN 0035-8711. Bibcode: 2017MNRAS.471..770M. 
  11. ↑ "V* WZ Dor". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=V%2A+WZ+Dor. 
  12. ↑ Eggleton, P. P.; Tokovinin, A. A. (11 September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. ISSN 0035-8711. Bibcode: 2008MNRAS.389..869E. 
  13. ↑ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode: 2000A&A...355L..27H. 
  14. ↑ Corben, P. M. (April 1971). "Photoelectric Magnitudes and Colours for Bright Southern Stars". Monthly Notes of the Astronomical Society of South Africa 30 (4): 37. ISSN 0024-8266. Bibcode: 1971MNSSA..30...37C. 
  15. ↑ Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (1 September 1972). "58th Name-List of Variable Stars". Information Bulletin on Variable Stars 717: 1. ISSN 0374-0676. Bibcode: 1972IBVS..717....1K. 
  16. ↑ Eggen, O. J. (September 1973). "The classification of intrinsic variables. IV. Very-small-amplitude, very-short-period red variables". The Astrophysical Journal 184: 793. doi:10.1086/152371. ISSN 0004-637X. Bibcode: 1973ApJ...184..793E. 
  17. ↑ Sloan, G. C.; Price, S. D. (December 1998). "The Infrared Spectral Classification of Oxygen-rich Dust Shells". The Astrophysical Journal Supplement Series (American Astronomical Society) 119 (2): 141–158. doi:10.1086/313156. ISSN 0067-0049. Bibcode: 1998ApJS..119..141S. 
  18. ↑ Lebzelter, Th.; Hron, J. (November 1999). "A search for Technetium in semiregular variables". Astronomy and Astrophysics 351: 533–542. ISSN 0004-6361. Bibcode: 1999A&A...351..533L. 
  19. ↑ 19.0 19.1 19.2 Tabur, V.; Bedding, T. R.; Kiss, L. L.; Moon, T. T.; Szeidl, B.; Kjeldsen, H. (21 December 2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society 400 (4): 1945–1961. doi:10.1111/j.1365-2966.2009.15588.x. ISSN 0035-8711. Bibcode: 2009MNRAS.400.1945T. 
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