Astronomy:8 Andromedae

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Short description: Multiple star system in the constellation Andromeda
8 Andromedae
8AndLightCurve.png
A light curve for 8 Andromedae, plotted from Hipparcos data[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Andromeda
Right ascension  23h 17m 44.64727s[2]
Declination +49° 00′ 55.0829″[2]
Apparent magnitude (V) 4.82[3]
Characteristics
Spectral type M2.5 III Ba0.5[4]
B−V color index 1.673[5]
Astrometry
Radial velocity (Rv)−8.0±0.3[6] km/s
Proper motion (μ) RA: +33.779[2] mas/yr
Dec.: +6.213[2] mas/yr
Parallax (π)5.6963 ± 0.1030[2] mas
Distance570 ± 10 ly
(176 ± 3 pc)
Absolute magnitude (MV)−1.727[5]
Details
Radius30[7] R☉
Surface gravity (log g)1.00±0.25[8] cgs
Temperature3,616±22[8] K
Metallicity [Fe/H]+0.04±0.08[8] dex
Rotational velocity (v sin i)5.0±1.0[9] km/s
Other designations
8 And, NSV 14484, BD+48° 3991, HD 219734, HIP 115022, HR 8860, SAO 52871, PPM 64030, WDS J23177+4901A[10]
Database references
SIMBADdata

8 Andromedae, abbreviated 8 And, is a probable triple star[11] system in the northern constellation of Andromeda. 8 Andromedae is the Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.82.[3] Based upon an annual parallax shift of 5.7 mas, it is located about 570 light years from the Earth. It is moving closer with a heliocentric radial velocity of −8 km/s.[6]

The primary component is an ageing red giant star with a stellar classification of M2.5 III Ba0.5.[4] The suffix notation indicates this is a mild barium star, which means the stellar atmosphere is enriched with s-process elements. It is either a member of a close binary system and has previously acquired these elements from a (now) white dwarf companion or else it is on the asymptotic giant branch and is generating the elements itself.[12] This is a periodic variable of unknown type, changing in brightness with an amplitude of 0.0161 magnitude at a frequency of 0.23354 d−1, or once every 4.3 days.[13]

The third component is the magnitude 13.0 star at an angular separation of 7.8″ along a position angle of 164°, as of 2015.[14] It has a Gaia Data Release 3 parallax of 5.7 mas and a proper motion almost identical to 8 Andromedae.[15] A number of other faint stars within a few arc-minutes of 8 Andromedae have been listed as companions, but none are at the same distance.[16]

Within Andromeda it is the second of a northerly chain asterism – 11 is further south-westward, with 7, 5, then 3 Andromedae in the other direction.

References

  1. ↑ Light Curve, ESA, https://www.cosmos.esa.int/web/hipparcos/java-tools/light-curve, retrieved 4 October 2022. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 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.
  3. ↑ 3.0 3.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  4. ↑ 4.0 4.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K. 
  5. ↑ 5.0 5.1 Soubiran, C. et al. (2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics 480 (1): 91–101, doi:10.1051/0004-6361:20078788, Bibcode: 2008A&A...480...91S. 
  6. ↑ 6.0 6.1 Gontcharov, G. A. (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, Bibcode: 2006AstL...32..759G. 
  7. ↑ Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367 (2): 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P. 
  8. ↑ 8.0 8.1 8.2 Prugniel, Ph. et al. (2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics 531: A165, doi:10.1051/0004-6361/201116769, Bibcode: 2011A&A...531A.165P. 
  9. ↑ Zamanov, R. K. et al. (October 2008), "Rotational velocities of the giants in symbiotic stars - III. Evidence of fast rotation in S-type symbiotics", Monthly Notices of the Royal Astronomical Society 390 (1): 377–382, doi:10.1111/j.1365-2966.2008.13751.x, Bibcode: 2008MNRAS.390..377Z. 
  10. ↑ "8 And". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=8+And. 
  11. ↑ Eggleton, P. P.; Tokovinin, A. A. (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, Bibcode: 2008MNRAS.389..869E. 
  12. ↑ Gomez, A. E. et al. (1997), "Absolute magnitudes and kinematics of barium stars", Astronomy and Astrophysics 319: 881, Bibcode: 1997A&A...319..881G. 
  13. ↑ Koen, Chris; Eyer, Laurent (2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society 331 (1): 45–59, doi:10.1046/j.1365-8711.2002.05150.x, Bibcode: 2002MNRAS.331...45K. 
  14. ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M. 
  15. ↑ 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.
  16. ↑ Mason, Brian D. et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M 



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