56 Persei

56 Persei
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 04h 24m 37.46102s[1]
Declination +33° 57′ 35.2908″[1]
Apparent magnitude (V) 5.77[2] (5.80 + 15.00[3] + 9.16[4] + 11.30[5])
Characteristics
Spectral type F4V + DA3.1[3] + F4[6] + ?
B−V color index 0.400±0.019[2]
Astrometry
Radial velocity (Rv)−31.8±2.9[2] km/s
Proper motion (μ) RA: +43.818[1] mas/yr
Dec.: −90.502[1] mas/yr
Parallax (π)23.5093 ± 0.0909 mas[1]
Distance138.7 ± 0.5 ly
(42.5 ± 0.2 pc)
Absolute magnitude (MV)2.73[2]
Details
56 Per Aa
Mass1.53[7] M☉
Radius1.97+0.05
−0.11[1] R☉
Luminosity7.166±0.034[8] L☉
Surface gravity (log g)4.32±0.14[8] cgs
Temperature6,629±225[8] K
Metallicity [Fe/H]−0.11±0.08[9] dex
Age1.811[8] Gyr
56 Per Ab
Mass0.90±0.12[10] M☉
Surface gravity (log g)8.46±0.2[10] cgs
Temperature16,420±420[10] K
Other designations
56 Per, BD+33° 854, HD 27786, HIP 20591, HR 1379, SAO 57216[11]
Database references
SIMBADdata

56 Persei is at least a triple star[10] and possibly a quadruple star[3] system in the northern constellation of Perseus. It is visible to the naked eye as a dim point of light with a combined apparent visual magnitude of 5.77.[2] The system is located 139 light-years (42.5 pc) distant from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −32 km/s.[2]

The main component is a binary system[12] with an orbital period of 47.3 years and a semimajor axis of 17.60 AU. The primary, designated component Aa, is an F-type main-sequence star with a stellar classification of F4V, a star that is currently fusing its core hydrogen.[7] It is 1.8[8] billion years old with 1.5[7] times the mass of the Sun and twice[1] the Sun's radius. It is radiating 7[8] times the luminosity of the Sun from its photosphere at an effective temperature of 6,629 K.[8]

The companion, component Ab, is a hydrogen–rich white dwarf star with a class of DA3.1,[3] having begun its main sequence life with more mass than the current primary and thus evolved into a compact star more rapidly. It now has 90% of the Sun's mass – much higher than the 0.6 M☉ for an average white dwarf – and an effective temperature of 16,420 K;[10] contributing an ultraviolet excess to the system.[3]

Component B shares a common linear motion through space with the primary, and thus may form a third member of the system. This star has 0.84 times the mass of the Sun and a projected separation of 178.2 AU from the primary.[7] The Washington Double Star Catalogue has it classified as a double star, with a magnitude 11.30 companion at an angular separation of 0.60″ along a position angle of 292°, as of 2002.[5]

  1. ^ a b c d e f g h Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Holberg2013 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Fabricius2002 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Cannon1949 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference Tokovinin2015 was invoked but never defined (see the help page).
  8. ^ a b c d e f g Cite error: The named reference David2015 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Gáspár2016 was invoked but never defined (see the help page).
  10. ^ a b c d e Cite error: The named reference Landsman1996 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).