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] |
Distance | 491 ± 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] |
Distance | 497 ± 5 ly (152 ± 2 pc) |
Details | |
HD 5789 | |
Mass | 2.74±0.12[9] M☉ |
Luminosity | 85.6+19.2 −15.6[9] L☉ |
Temperature | 9,977[5] K |
Rotational velocity (v sin i) | 249[9] km/s |
HD 5788 | |
Mass | 2.67±0.12[9] M☉ |
Luminosity | 73.3+18.4 −14.7[9] L☉ |
Temperature | 9,840[5] K |
Rotational velocity (v sin i) | 270[9] km/s |
Other designations | |
HD 5789: HR 283, SAO 36833[10] | |
HD 5788: HR 282, SAO 36832[11] | |
Database references | |
HD 5789 | |
SIMBAD | data |
HD 5788 | |
SIMBAD | data |
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]