HR 178

HD 3883
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 41m 36.0370s[1]
Declination +24° 37′ 44.43″[1]
Apparent magnitude (V) 6.046[2]
Characteristics
Spectral type kA5hF1mF2[3]
B−V color index 0.287[2]
Variable type suspected[4]
Astrometry
Radial velocity (Rv)−15.60±0.9[5] km/s
Proper motion (μ) RA: 106.272±0.499[1] mas/yr
Dec.: −12.324±0.306[1] mas/yr
Parallax (π)8.0963 ± 0.2630 mas[1]
Distance400 ± 10 ly
(124 ± 4 pc)
Orbit[6]
Period (P)21.26 yr
Semi-major axis (a)0.126″
Eccentricity (e)0.5
Details
Mass2.44[7] M☉
Radius3.82[1] R☉
Luminosity45[1] L☉
Surface gravity (log g)3.80±0.14[8] cgs
Temperature7800±200[8] K
Metallicity [Fe/H]0.53±0.13[8] dex
Rotational velocity (v sin i)18[3] km/s
Other designations
HIP 3269, HD 3883, BD+23°94, SAO 74200.
Database references
SIMBADdata

HR 178 is a probable binary star in the constellation Andromeda. Located approximately 124 parsecs (400 ly) distant, it is an evolved Am star[9] with a combined apparent magnitude of 6.06, meaning that it can only be seen with the naked eye on dark, clear nights. The star is suspected of variability, possibly varying between magnitudes 6.04 and 6.06.[4] The variable magnitude period of HD 3883 is about 9.17 min.[10]

The spectrum of HR 178 has been extensively studied for establishing element abundances in the evolved Am stars. It is given a spectral class of kA5hF1mF2, meaning its spectral type is A5, F1, or F2, depending on the particular spectral lines examined. The evolutionary stage of the star, and its mass determined from comparison with theoretical evolutionary tracks, is not precisely determined. However, it is very close to the end of its main sequence evolution and the margin of error in its mass is only about 0.1 M☉.[9]

HR 178 has been suspected of being a binary star since 1938 when its spectrum was interpreted as being composite.[11] The pair were resolved using speckle interferometry in 1983.[12] The companion is modelled to be between 1.5 and 3 magnitudes fainter than the primary star.[13] Although there have since been several failed attempts to resolve the pair, a tentative orbit has been calculated with a period of 21.26 years and an eccentricity of 0.5.[6]

  1. ^ a b c d e f g Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b Cite error: The named reference TYCHO was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference abt was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference AAVSO was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Malkov2012 was invoked but never defined (see the help page).
  7. ^ Hui-Bon-Hoa, A. (June 2000). "Metal abundances of field A and Am stars". Astronomy and Astrophysics Supplement Series. 144 (2): 203–209. Bibcode:2000A&AS..144..203H. doi:10.1051/aas:2000207. ISSN 0365-0138. S2CID 123151702.
  8. ^ a b c Cite error: The named reference PASTEL was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Buckhart was invoked but never defined (see the help page).
  10. ^ Chagnon, François (2009). Searching for northern roap stars: the UBC-OAN photometric survey. University of British Columbia (Thesis). doi:10.14288/1.0099308. S2CID 124888408.
  11. ^ Cite error: The named reference hynek was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference mcalister was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference bonneau was invoked but never defined (see the help page).