Mu1 Cancri

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Mu1 Cancri
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cancer
Right ascension  08h 06m 18.39576s[1]
Declination +22° 38′ 07.7621″[1]
Apparent magnitude (V) +5.99[2]
Spectral type M3 III[3]
B−V color index +1.66[2]
Variable type Lb[3]
Radial velocity (Rv)+29.61±0.57[4] km/s
Proper motion (μ) RA: −5.97[1] mas/yr
Dec.: −9.06[1] mas/yr
Parallax (π)4.38 ± 0.53[1] mas
Distanceapprox. 740 ly
(approx. 230 pc)
Absolute magnitude (MV)−0.79[5]
Luminosity1,141[6] L
Temperature3,611[6] K
Other designations
μ1 Cnc, 9 Cancri, BL Cancri, BD+23° 1887, HD 66875, HIP 39659, HR 3169, SAO 79940[7]
Database references

Mu1 Cancri, Latinized from μ1 Cancri, is a evolved red giant star in the zodiac constellation of Cancer. Parallax measurements made by the Hipparcos spacecraft put it about 740 light years (230 parsecs) from the Sun.[1] At that distance, the visual magnitude is diminished by an extinction factor of 0.28.[8] The name Mu1 comes from the Bayer naming system: the "1" in the name is because (from Earth) it appears to be close to 10 Cancri (Mu2 Cancri). Mu1 Cancri is a variable star and was given the variable star designation BL Cancri, it is a slow irregular variable[3] with periods of 22.6, 37.8, and 203.7 days.[9]


  1. ^ a b c d e f 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.
  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. ^ a b c Lebzelter, T.; Hron, J. (December 2003), "Technetium and the third dredge up in AGB stars. I. Field stars", Astronomy and Astrophysics, 411: 5335–42, arXiv:astro-ph/0310018, Bibcode:2003A&A...411..533L, doi:10.1051/0004-6361:20031458.
  4. ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  5. ^ 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.
  6. ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  7. ^ "mu.01 Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-17.
  8. ^ Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272.
  9. ^ Tabur, V.; Bedding, T. R. (2009), "Long-term photometry and periods for 261 nearby pulsating M giants", Monthly Notices of the Royal Astronomical Society, 400 (4): 1945–61, arXiv:0908.3228, Bibcode:2009MNRAS.400.1945T, doi:10.1111/j.1365-2966.2009.15588.x.