8 Andromedae

Not to be confused with Andromeda VIII.
8 Andromedae

A light curve for 8 Andromedae, plotted from Hipparcos data[1]
Observation data
Epoch J2000      Equinox J2000
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 mas[2]
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.

  1. ^ Cite error: The named reference HIPCurve was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Soubiran2008 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Fracassini2001 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference Prugniel2011 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Zamanov2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference gomez1997 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference koen2002 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference dr3b was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference wds was invoked but never defined (see the help page).