HD 5788 and HD 5789

HD 5789/5788
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
HD 5789
Right ascension 01h 00m 03.55767s[1]
Declination +44° 42′ 47.6898″[1]
Apparent magnitude (V) 6.06[2]
HD 5788
Right ascension 01h 00m 03.38277s[1]
Declination +44° 42′ 40.0515″[1]
Apparent magnitude (V) 6.763[3]
Characteristics
HD 5789
Spectral type B9.5Vnn (λ Boo)[4]
B−V color index −0.031[5]
HD 5788
Spectral type A2 Vn[6]
B−V color index −0.010[5]
Astrometry
Radial velocity (Rv)+4.4±3.3[7] km/s
Proper motion (μ) RA: +13.85[8] mas/yr
Dec.: −23.83[8] mas/yr
Parallax (π)6.6432 ± 0.0809 mas[1]
Distance491 ± 6 ly
(151 ± 2 pc)
Proper motion (μ) RA: +11.582[1] mas/yr
Dec.: −24.369[1] mas/yr
Parallax (π)6.5625 ± 0.0688 mas[1]
Distance497 ± 5 ly
(152 ± 2 pc)
Details
HD 5789
Mass2.74±0.12[9] M☉
Luminosity85.6+19.2
−15.6[9] L☉
Temperature9,977[5] K
Rotational velocity (v sin i)249[9] km/s
HD 5788
Mass2.67±0.12[9] M☉
Luminosity73.3+18.4
−14.7[9] L☉
Temperature9,840[5] K
Rotational velocity (v sin i)270[9] km/s
Other designations
BD+43°193, HIP 4675, ADS 824, WDS J01001+4443
HD 5789: HR 283, SAO 36833[10]
HD 5788: HR 282, SAO 36832[11]
Database references
HD 5789
SIMBADdata
HD 5788
SIMBADdata

HD 5789 and HD 5788 is a pair of stars comprising a binary star[12] system in the northern constellation of Andromeda. Located approximately 151 parsecs (490 ly) away, the primary is a hot, massive blue star with an apparent magnitude of 6.06 while the secondary is slightly smaller and cooler, with an apparent magnitude of 6.76. Both stars are main-sequence stars, meaning that they are currently fusing hydrogen into helium in their cores. As of 2016, the pair had an angular separation of 7.90″ along a position angle of 195°.[13] While both have a similar proper motion and parallax, there's still no proof that the pair is gravitationally bound.

The primary component is HD 5789, a B-type main-sequence star with a stellar classification of B9.5Vnn (λ Boo), where the 'n' indicates "nebulous" lines due to rapid rotation. Abt and Morrell (1995) listed it as a Lambda Boötis star,[4] although this is disputed.[14] It has 2.7 times the mass of the Sun and is spinning rapidly with a projected rotational velocity of 249 km/s.[9] The star is radiating 86[9] times the Sun's luminosity from its photosphere at an effective temperature of 9,977 K.[5]

The fainter secondary component is an A-type main-sequence star with a class of A2 Vn.[6] It shows a projected rotational velocity of 270 km/s and has 2.7 times the Sun's mass. The star shines with 73[9] times the Sun's luminosity at an effective temperature of 9,840 K.[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. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference tycho2 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Abt1995 was invoked but never defined (see the help page).
  5. ^ a b c d e f Cite error: The named reference Soubiran2016 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  9. ^ a b c d e f g h i Cite error: The named reference zorec2012 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD_A was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD_B 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).
  13. ^ Cite error: The named reference WDSC2014 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Murphy2015 was invoked but never defined (see the help page).