56 Ursae Majoris (56 UMa) is a binary star in the constellation Ursa Major. At an apparent magnitude of 5.03, it is a faint star but visible to the naked eye depending on factors such as light pollution and eyesight. Parallax measurements derive a distance of 555 light-years.

It is a single-lined spectroscopic binary with an orbital period of about 45 years.[5] The primary is an evolved giant star with a spectral class G7IIIBa0.3, a Barium star.[3] The companion star is likely a heavy neutron star born by a supernova that exploded around 100,000 years ago.[7]

References

  1. 1 2 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. ↑ 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. 1 2 Lu, Phillip K. (1991). "Taxonomy of barium stars". Astronomical Journal. 101: 2229–2254. Bibcode:1991AJ....101.2229L. doi:10.1086/115845.
  4. 1 2 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. 1 2 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. 1 2 3 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  7. 1 2 3 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.
  8. 1 2 3 Baines, Ellyn K.; Clark, James H.; Kingsley, Bradley I.; Schmitt, Henrique R.; Stone, Jordan M. (2025-05-07). "Vintage NPOI: New and Updated Angular Diameters for 145 Stars". The Astronomical Journal. 169 (6): 293. arXiv:2506.02912. doi:10.3847/1538-3881/adc930. ISSN 1538-3881.


source: https://en.wikipedia.org/wiki/56_Ursae_Majoris