Loading

  • 21 Aug, 2019

  • By, Wikipedia

Omicron Andromedae
Omicron Andromedae (ο And, ο Andromedae) is a star system in the constellation Andromeda. It is approximately 350 light years from Earth. The system as a whole is classified as a blue-white B-type giant, with a mean combined apparent magnitude of +3.62.

System

Omicron Andromedae is a multiple star containing at least three components. It may consist of two close pairs in a wider orbit, making a four-star system, although the binarity of the primary star is in doubt. This star system has a peculiar velocity of 34.5 ± 5.9 km/s.

The components A and B were first resolved in 1949, when they were reported to be separated by less than 0.1". In 1975 they were separated by 0.375" and by 2014 by only 0.21". An orbit has been derived with a period of 118 years. The companion is 2.3 magnitudes fainter than the primary star.

In 1975, a companion was discovered by speckle interferometry only 0.05" from component A. Components Aa and Ab orbit every 5.6 years, although the existence of this companion is now doubted.

A spectroscopic binary in the system was suspected and in 1988 it was confirmed. Although a clear 33.01 day period was seen, it was unclear which component was the pair seen in the spectrum. Eventually, it was settled that component B was a close spectroscopic binary.

Properties

A light curve for Omicron Andromedae, plotted from TESS data

Omicron Andromedae is a Gamma Cassiopeiae type variable star and the system's brightness varies from magnitude +3.58 to +3.78. The variable component is the brightest and most massive star in the system, Aa. Omicron Andromedae also shows variations with a period of about a day, similar to a β Lyrae-type eclipsing variable, but these are thought to be intrinsic to one of the components and not due to eclipses.

The spectrum is predominantly that of a B6 giant star, from the brightest component in the system. It is a shell star and the spectrum contains emission lines with variable profiles.

Spectral lines similar to an A2 star are also detectable in the spectrum and these are thought to originate in the B component.

References

  1. ^ 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. ^ Nicolet, B. (1978). "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System". Observatory. Bibcode:1978ppch.book.....N.
  3. ^ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
  4. ^ Slettebak, A (1982). "Spectral types and rotational velocities of the brighter Be stars and A-F type shell stars". Astrophysical Journal Supplement Series. 50: 55. Bibcode:1982ApJS...50...55S. doi:10.1086/190820.
  5. ^ Olević, D.; Cvetković, Z. (2006). "Dynamical Masses of the Components in o Andromedae". The Astronomical Journal. 131 (3): 1721. Bibcode:2006AJ....131.1721O. doi:10.1086/499539.
  6. ^ Zasche, P.; Wolf, M.; Hartkopf, W. I.; Svoboda, P.; Uhlař, R.; Liakos, A.; Gazeas, K. (2009). "A Catalog of Visual Double and Multiple Stars with Eclipsing Components". The Astronomical Journal. 138 (2): 664–679. arXiv:0907.5172. Bibcode:2009AJ....138..664Z. doi:10.1088/0004-6256/138/2/664. S2CID 17089387.
  7. ^ Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Washington: 0. Bibcode:1953GCRV..C......0W.
  8. ^ Underhill, A. B.; et al. (November 1979). "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars". Monthly Notices of the Royal Astronomical Society. 189 (3): 601–605. Bibcode:1979MNRAS.189..601U. doi:10.1093/mnras/189.3.601.
  9. ^ Mitrofanova, A.; Dyachenko, V.; Beskakotov, A.; Balega, Yu.; Maksimov, A.; Rastegaev, D. (2021). "Speckle Interferometry of Nearby Multiple Stars. II. 2007-2020 Positional Measurements and Orbits of Sixteen Objects". The Astronomical Journal. 162 (4): 156. Bibcode:2021AJ....162..156M. doi:10.3847/1538-3881/ac1a78. S2CID 237603742.
  10. ^ Zhuchkov, R. Ya; Malogolovets, E. V.; Kiyaeva, O. V.; Orlov, V. V.; Bikmaev, I. F.; Balega, Yu.Yu; Safina, D. I. (2010). "Physical parameters and dynamical properties of the multiple star o and". Astronomy Reports. 54 (12): 1134–1149. Bibcode:2010ARep...54.1134Z. doi:10.1134/S1063772910120061. S2CID 121960504.
  11. ^ Tokovinin, Andrei (2018). "The Updated Multiple Star Catalog". The Astrophysical Journal Supplement Series. 235 (1): 6. arXiv:1712.04750. Bibcode:2018ApJS..235....6T. doi:10.3847/1538-4365/aaa1a5. S2CID 119047709.
  12. ^ Hill, G. M.; Walker, G. A. H; Dinshaw, N; Yang, S; Harmance, P (1988). "Omicron Andromedae is quadruple". Publications of the Astronomical Society of the Pacific. 100: 243. Bibcode:1988PASP..100..243H. doi:10.1086/132161.
  13. ^ Balona, L. A.; Dziembowski, W. A. (October 1999). "Excitation and visibility of high-degree modes in stars". Monthly Notices of the Royal Astronomical Society. 309 (1): 221–232. Bibcode:1999MNRAS.309..221B. doi:10.1046/j.1365-8711.1999.02821.x.
  14. ^ Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873.
  15. ^ "omi And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-06-23.
  16. ^ Wilson, R. H. (1950). "Observations of double stars". The Astronomical Journal. 55: 153. Bibcode:1950AJ.....55..153W. doi:10.1086/106378.
  17. ^ Horch, Elliott P; Van Belle, Gerard T; Davidson, James W; Ciastko, Lindsay A; Everett, Mark E; Bjorkman, Karen S (2015). "Observations of Binary Stars with the Differential Speckle Survey Instrument. VI. Measures during 2014 at the Discovery Channel Telescope". The Astronomical Journal. 150 (5): 151. arXiv:1509.03498. Bibcode:2015AJ....150..151H. doi:10.1088/0004-6256/150/5/151. S2CID 119115316.
  18. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Omicron_Andromedae&oldid=1234954667"