  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Major |
| 65 UMa ABC | |
| Right ascension | 11h 55m 05.74925s[1] |
| Declination | +46° 28′ 36.6408″[1] |
| Apparent magnitude (V) | +6.54[2] (A/B/C = 6.7 / 8.5 / 8.32)[3] |
| 65 UMa D | |
| Right ascension | 11h 55m 11.33152s[1] |
| Declination | +46° 28′ 11.2150″[1] |
| Apparent magnitude (V) | +6.965[4] |
| Characteristics | |
| 65 UMa ABC | |
| Spectral type | A7 / A7 / A3 / ? / ?[5] |
| U−B color index | +0.08[2] |
| B−V color index | +0.11[2] |
| Variable type | Algol[5] |
| 65 UMa D | |
| Spectral type | A0p[6] |
| U−B color index | +0.01[2] |
| B−V color index | +0.02[2] |
| Astrometry | |
| 65 UMa ABC | |
| Radial velocity (Rv) | −3.90±4.4[7] km/s |
| Proper motion (μ) | RA: 10.41[1] mas/yr Dec.: 2.38[1] mas/yr |
| Parallax (π) | 4.72 ± 0.58 mas[1] |
| Distance | approx. 690 ly (approx. 210 pc) |
| Absolute magnitude (MV) | −0.05[8] |
| 65 UMa D | |
| Radial velocity (Rv) | −7.00±3.7[9] km/s |
| Proper motion (μ) | RA: 11.82[1] mas/yr Dec.: 0.39[1] mas/yr |
| Parallax (π) | 3.37 ± 0.56 mas[1] |
| Distance | approx. 1,000 ly (approx. 300 pc) |
| Absolute magnitude (MV) | −0.1[10] |
| Orbit[5] | |
| Primary | 65 UMa Aa1 |
| Companion | 65 UMa Aa2 |
| Period (P) | 1.73043 d |
| Inclination (i) | 86.5±0.2° |
| Semi-amplitude (K1) (primary) | 133.3±4.2 km/s |
| Semi-amplitude (K2) (secondary) | 135.7±4.2 km/s |
| Orbit[5] | |
| Primary | 65 UMa Aa |
| Companion | 65 UMa Ab |
| Period (P) | 641.5±16.7 |
| Eccentricity (e) | 0.169±0.048 |
| Inclination (i) | 47° |
| Semi-amplitude (K1) (primary) | 13.7[3] km/s |
| Semi-amplitude (K2) (secondary) | 19.9±2.7 km/s |
| Orbit[5] | |
| Primary | 65 UMa A |
| Companion | 65 UMa B |
| Period (P) | 118.209±0.690 yr |
| Semi-major axis (a) | 208.2±9.7 mas |
| Eccentricity (e) | 0.504±0.006 |
| Inclination (i) | 38.1±2.4° |
| Longitude of the node (Ω) | 92.1±4.2° |
| Periastron epoch (T) | 2447516.9±126.8 |
| Argument of periastron (ω) (secondary) | 202.7±1.3° |
| Details | |
| 65 UMa Aa1 | |
| Mass | 1.74±0.06[5] M☉ |
| Radius | 1.86±0.08[5] R☉ |
| Temperature | 8,000[5] K |
| 65 UMa Aa2 | |
| Mass | 1.71±0.06[5] M☉ |
| Radius | 1.81±0.08[5] R☉ |
| Temperature | 7,948±20[5] K |
| 65 UMa Ab | |
| Mass | 2.4±0.4[5] M☉ |
| 65 UMa B | |
| Mass | 2.4±2.0[5] M☉ |
| 65 UMa C | |
| Mass | 2.01[3] M☉ |
| 65 UMa D | |
| Mass | 2.31[11](3.02 + 1.64[3]) M☉ |
| Radius | 2.93[11] R☉ |
| Luminosity | 79[11] L☉ |
| Surface gravity (log g) | 3.85[11] cgs |
| Temperature | 8,600[11] K |
| Age | 525[11] Myr |
| Other designations | |
| 65 UMa ABC: DN UMa, BD+47°1913, HD 103483, HIP 58112, HR 4560, SAO 43945 | |
| 65 UMa D: BD+47°1914, HD 103498, HIP 58117, HR 4561, SAO 43946 | |
| Database references | |
| 65 UMa AB | |
| 65 UMa C | |
| 65 UMa D | |
65 Ursae Majoris, abbreviated as 65 UMa, is a star system in the constellation of Ursa Major. With a combined apparent magnitude of about 6.5,[2] it is at the limit of human eyesight and is just barely visible to the naked eye in ideal conditions. It is about 760 light years away from Earth.
65 Ursae Majoris is a sextuple star system. It contains six stars in a hierarchical orbit where each star orbits its inner stars. Such systems are uncommon, with only a few sextuple stars known.[5] Higher-multiplicity star systems are uncommon because they are less stable than their simpler counterparts, and often decay into smaller systems.
- ^ a b c d e f g h i j van Leeuwen, F.; et al. (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 Tolbert, C. R. (1964). "A UBV Study of 94 Wide Visual Binaries". Astrophysical Journal. 139: 1105. Bibcode:1964ApJ...139.1105T. doi:10.1086/147852.
- ^ a b c d Tokovinin, A. A. (1997). "MSC - a catalogue of physical multiple stars". Astronomy & Astrophysics Supplement Series. 124: 75–84. Bibcode:1997A&AS..124...75T. doi:10.1051/aas:1997181.
- ^ Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
- ^ a b c d e f g h i j k l m n Zasche, P.; Uhlář, R.; Šlechta, M.; Wolf, M.; Harmanec, P.; Nemravová, J. A.; Korčáková, D. (2012). "Unique sextuple system: 65 Ursae Majoris". Astronomy & Astrophysics. 542: A78. arXiv:1207.0651. Bibcode:2012A&A...542A..78Z. doi:10.1051/0004-6361/201219134. S2CID 56328797.
- ^ Pandey, Chhavi P.; Shulyak, Denis V.; Ryabchikova, Tanya; Kochukhov, Oleg (2012). "Abundance and stratification analysis of the CP star HD 103498". Astronomical Society of India Conference Series. 6: 225. arXiv:1106.3727. Bibcode:2012ASInC...6..225P. doi:10.1111/j.1365-2966.2011.19281.x. S2CID 56288919.
- ^ Gontcharov, G. A. (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.
- ^ 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.
- ^ Kharchenko, N. V.; et al. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. S2CID 119323941.
- ^ Gomez, A. E.; Luri, X.; Grenier, S.; Figueras, F.; North, P.; Royer, F.; Torra, J.; Mennessier, M. O. (1998). "The HR-diagram from HIPPARCOS data. Absolute magnitudes and kinematics of BP - AP stars". Astronomy and Astrophysics. 336: 953. Bibcode:1998A&A...336..953G.
- ^ a b c d e f Glagolevskij, Yu. V. (2019). "On Properties of Main Sequence Magnetic Stars". Astrophysical Bulletin. 74 (1): 66. Bibcode:2019AstBu..74...66G. doi:10.1134/S1990341319010073. S2CID 149900274.