Back 78 Ursae Majoris AST 78 Ursae Majoris Spanish 78 Ursae Majoris French 78 Ursae Majoris Italian 78 Большой Медведицы Russian 78 Ursae Majoris Swedish 大熊座78 Chinese

78 Ursae Majoris

78 Ursae Majoris
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
Right ascension 13h 00m 43.69949s[1]
Declination +56° 21′ 58.8102″[1]
Apparent magnitude (V) 4.93[2] (5.02 + 7.88)[3]
Characteristics
Evolutionary stage main sequence
Spectral type F2V[4] + G6V[5]
U−B color index +0.00[6]
B−V color index +0.368±0.010[2]
Astrometry
Radial velocity (Rv)−5.1±0.9[2] km/s
Proper motion (μ) RA: 107.94[1] mas/yr
Dec.: 2.05[1] mas/yr
Parallax (π)39.30 ± 0.38 mas[1]
Distance83.0 ± 0.8 ly
(25.4 ± 0.2 pc)
Absolute magnitude (MV)+2.84[7]
Orbit[8]
Period (P)104.9±0.6 yr
Semi-major axis (a)1.208±0.010″
Eccentricity (e)0.388±0.009
Inclination (i)46.9±0.9°
Longitude of the node (Ω)88.0±1.1°
Periastron epoch (T)B 1921.224±0.403
Argument of periastron (ω)
(secondary)		119.2±1.5°
Details
78 UMa A
Mass1.34[9] M☉
Radius1.62±0.24[10] R☉
Luminosity5.75[2] L☉
Surface gravity (log g)4.26±0.14[9] cgs
Temperature6,908±235[9] K
Metallicity [Fe/H]0.01±0.05[11] dex
Rotation19.2 ± 2.9 h[10]
Rotational velocity (v sin i)91.7±4.6[12] km/s
Age785[9] Myr
Other designations
78 UMa, BD+57°1408, HD 113139, HIP 63503, HR 4931, SAO 28601, WDS J13007+5622[13]
Database references
SIMBADThe system
A
B

78 Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.93.[13] Parallax estimates by Hipparcos put it at a distance of 83 light-years (25 pc),[1] but it is drifting closer with a radial velocity of −5 km/s.[2] The system is a candidate member of the Ursa Major Moving Group.[14]

The binary nature of this system was announced by S. W. Burnham in 1894.[15] The pair orbit each other with a period of 105 years and an eccentricity of 0.39. Their semimajor axis has an angular size of 1.2″ and the orbital plane is inclined by 47°.[8]

The primary member, designated component A, has a magnitude of 5.02[3] and is an F-type main-sequence star with a stellar classification of F2V.[4] It is 785[9] million years old and is spinning with a projected rotational velocity of 92 km/s.[12] The star has 1.34[9] times the mass of the Sun and is radiating 5.75[2] times the Sun's luminosity from its photosphere at an effective temperature of 6,908 K.[9]

The secondary, designated component B, has a visual magnitude of 7.88.[3] It is a G-type main-sequence star with a class of G6V.[5] The star is a suspected variable.[16]

  1. ^ a b c d e f Cite error: The named reference HIP 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 Cite error: The named reference Fabricius was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Gray was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Edwards1976 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference EgUBV was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Eggen1998 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Drummond2014 was invoked but never defined (see the help page).
  9. ^ a b c d e f g Cite error: The named reference David2015 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference Justesen_Albrecht_2020 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference gaspar2016 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference vonEiff2012 was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference nakajima2012 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference ORB6 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Baize1989 was invoked but never defined (see the help page).
From Wikipedia, the free encyclopedia · View on Wikipedia

Developed by Nelliwinne