56 Ursae Majoris

56 Ursae Majoris
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
Right ascension 11h 22m 49.58373s[1]
Declination +43° 28′ 57.7267″[1]
Apparent magnitude (V) 5.03[2]
Characteristics
Spectral type G7IIIBa0.3[3]
U−B color index +0.82[4]
B−V color index +1.02[4]
Astrometry
Radial velocity (Rv)1.01 ± 0.05[5] km/s
Proper motion (μ) RA: -37.42[1] mas/yr
Dec.: -14.26[1] mas/yr
Parallax (π)6.12 ± 0.27 mas[1]
Distance530 ± 20 ly
(163 ± 7 pc)
Orbit[6]
Period (P)16911+438
−401 d
Semi-major axis (a)22.9+1.0
−1.1 au
Eccentricity (e)0.562+0.012
−0.012
Inclination (i)68+3.6
−3.4°
Longitude of the node (Ω)60+3
−3°
Periastron epoch (T)2468401+432
−385
Argument of periastron (ω)
(secondary)		286+2.3
−2.3°
Details[6]
56 UMa A
Mass4.3 ± 0.2 M☉
Surface gravity (log g)2.3 ± 0.6 cgs
Temperature4917 ± 34 K
56 UMa B
Mass1.31+0.11
−0.12 M☉
Other designations
BD+44° 2083, FK5 2908, HD 98839, HIP 55560, HR 4392, SAO 43719
Database references
SIMBADdata

56 Ursae Majoris (56 UMa) is a star in the constellation Ursa Major. Its apparent magnitude is 5.03.[2] It is a single-lined spectroscopic binary with an orbital period of about 45 years.[5] The companion star is likely a heavy neutron star born by a supernova that exploded around 100,000 years ago.[6]

  1. ^ a b c d e 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.
  2. ^ a b Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. ^ Lu, Phillip K. (1991). "Taxonomy of barium stars". Astronomical Journal. 101: 2229–2254. Bibcode:1991AJ....101.2229L. doi:10.1086/115845.
  4. ^ a b Fernie, J. D. (1983). "New UBVRI photometry for 900 supergiants". Astrophysical Journal Supplement Series. 52 (7–22): 7. Bibcode:1983ApJS...52....7F. doi:10.1086/190856.
  5. ^ a b Pourbaix, D.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727–732. arXiv:astro-ph/0406573. Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. S2CID 119387088.
  6. ^ a b c Escorza, A.; Karinkuzhi, D.; Jorissen, A.; Van Eck, S.; Schmelz, J. T.; Verschuur, G. L.; Boffin, H. M. J.; De Rosa, R. J.; Van Winckel, H. (2023). "A neutron star candidate in the long-period binary 56 UMa". Astronomy and Astrophysics. 670: L14. arXiv:2301.06531. Bibcode:2023A&A...670L..14E. doi:10.1051/0004-6361/202245796. S2CID 255941814.