Astronomy:Omega Andromedae

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Short description: Binary star system in the constellation Andromeda
Omega Andromedae
Diagram showing star positions and boundaries of the Andromeda constellation and its surroundings
Location of ω Andromedae (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Andromeda
Right ascension  01h 27m 39.38072s[1]
Declination +45° 24′ 24.0651″[1]
Apparent magnitude (V) +4.83[2][3]
Characteristics
Spectral type F5 IVe[4] or F3 V + F5 V[5]
U−B color index +0.00[3]
B−V color index +0.42[3]
Astrometry
Radial velocity (Rv)+14.7[2] km/s
Proper motion (μ) RA: 357.564(127)[1] mas/yr
Dec.: −110.039(118)[1] mas/yr
Parallax (π)34.7332 ± 0.1341[1] mas
Distance93.9 ± 0.4 ly
(28.8 ± 0.1 pc)
Absolute magnitude (MV)+2.57[2]
Details
ω And A
Mass0.963±0.049[5] M☉
Radius2.2[6] R☉
Luminosity7.1[7] L☉
Temperature6,628[7] K
Metallicity [Fe/H]−0.16[2] dex
Rotational velocity (v sin i)57.1[8] km/s
Age2.1[2] Gyr
ω And B
Mass0.860±0.051[5] M☉
Other designations
48 Andromedae, BD+44°307, FK5 1040, HD 8799, HIP 6813, HR 417, SAO 37228, PPM 44006[4]
Database references
SIMBADdata

Omega Andromedae (ω And, ω Andromedae) is the Bayer designation for a slowly co-rotating[failed verification] binary star system[9] in the northern constellation of Andromeda. Parallax measurements made during the Gaia mission make this system to be approximately 93.9 light-years (28.8 parsecs) from Earth. Its apparent visual magnitude is +4.83,[2] which makes it bright enough to be seen with the naked eye.

The primary component has a stellar classification of F5 IVe.[4] The IV luminosity class indicates that it is probably a subgiant star that is in the process of evolving away from the main sequence as the supply of hydrogen at its core depletes. However, Abt (1985) gives a classification of F3 V, suggesting it is an F-type main-sequence star.[5] The measured angular diameter of the primary star is 0.70 ± 0.03 mas.[10] At the system's estimated distance this yields a size of about 2.2 times that of the Sun.[6] It is emitting about seven times solar luminosity from its outer atmosphere at an effective temperature of 6,628 K.[7] This heat gives it the yellow-white-hued glow of an F-type star.[11]

In 2008, the companion star was resolved using adaptive optics at the Lick Observatory. Later observations showed the magnitude difference between the two stars is 3.65 ± 0.03 and they are separated by 0.669 arcsecond.[9] Abt (1985) lists the class as F5 V.[5]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Nordström, B. et al. (May 2004), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ˜14 000 F and G dwarfs", Astronomy and Astrophysics 418: 989–1019, doi:10.1051/0004-6361:20035959, Bibcode: 2004A&A...418..989N. 
  3. ↑ 3.0 3.1 3.2 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J. 
  4. ↑ 4.0 4.1 4.2 "ome And". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ome+And. 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 Farrington, C. D. et al. (September 2014), "Separated Fringe Packet Observations with the CHARA Array. II. ω Andromeda, HD 178911, and ξ Cephei", The Astronomical Journal 148 (3): 8, doi:10.1088/0004-6256/148/3/48, 48, Bibcode: 2014AJ....148...48F. 
  6. ↑ 6.0 6.1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 . The radius (R*) is given by:
    2⋅R*=(28.6⋅0.70⋅10−3) AU0.0046491 AU/R⨀≈4.31⋅R⨀
  7. ↑ 7.0 7.1 7.2 do Nascimento, J. D. Jr. et al. (July 2003), "On the link between rotation, chromospheric activity and Li abundance in subgiant stars", Astronomy and Astrophysics 405 (2): 723–731, doi:10.1051/0004-6361:20030633, Bibcode: 2003A&A...405..723D. 
  8. ↑ Schröder, C.; Reiners, Ansgar; Schmitt, Jürgen H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo", Astronomy and Astrophysics 493 (3): 1099–1107, doi:10.1051/0004-6361:200810377, Bibcode: 2009A&A...493.1099S, http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/9690/aa10377-08.pdf?sequence=2 [yes|permanent dead link|dead link}}]
  9. ↑ 9.0 9.1 Gladysz, Szymon; Christou, Julian C. (June 2009), "Reference-Less Detection, Astrometry, and Photometry of Faint Companions with Adaptive Optics", The Astrophysical Journal 698 (1): 28–42, doi:10.1088/0004-637X/698/1/28, Bibcode: 2009ApJ...698...28G. 
  10. ↑ Richichi, A.; Percheron, I.; Khristoforova, M. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431 (2): 773–777, doi:10.1051/0004-6361:20042039, Bibcode: 2005A&A...431..773R 
  11. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16. 



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