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.
| 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 |
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]
References
edit- ^ a b c d e f g h 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.
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27. Bibcode:2000A&A...355L..27H. doi:10.1888/0333750888/2862.
- ^ a b Abt, Helmut A.; Morrell, Nidia I. (July 1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
- ^ a b c d e f Soubiran, Caroline; et al. (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497. S2CID 119258214.
- ^ a b Cowley, A.; et al. (April 1969). "A study of the bright A stars. I. A catalogue of spectral classifications". Astronomical Journal. 74: 375–406. Bibcode:1969AJ.....74..375C. doi:10.1086/110819.
- ^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
- ^ a b van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ a b c d e f g h i Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. S2CID 55586789.
- ^ "HD 5789". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 10, 2018.
- ^ "HD 5788". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 10, 2018.
- ^ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920
- ^ Murphy, Simon J.; et al. (October 2015), "An Evaluation of the Membership Probability of 212 λ Boo Stars. I. A Catalogue", Publications of the Astronomical Society of Australia, 32: 43, arXiv:1508.03633, Bibcode:2015PASA...32...36M, doi:10.1017/pasa.2015.34, S2CID 59405545, e036.