Sigma1 Cancri is a binary star system[1] in the zodiac constellation of Cancer. Its name is a Bayer designation that is Latinized from σ1 Cancri, and abbreviated Sigma1 Cnc or σ1 Cnc. The primary component is faintly visible to the naked eye, with an apparent visual magnitude of +5.68.[2] Based upon an annual parallax shift of 15.51 mas as seen from Earth,[3] this star is located around 221 light-years (68 pc) from the Sun. It is moving further away with a line of sight velocity of −11 km/s.[4]

This is a chemically peculiar[5] A-type main sequence star with a stellar classification of A8 Vas.[6] At an age of about 301[7] million years, Sigma1 Cancri is around 67% of the way through its main sequence lifespan.[5] The star has 1.8 times the mass of the Sun and is radiating 18 times the Sun's luminosity from its photosphere at an effective temperature of 7,780 K.[8]

There is a magnitude 13.3 companion at an angular separation of 5.2 arc seconds along a position angle of 276°, as of 2011.[9] At that distance, the pair have a projected separation of 333.2 AU (0.005269 ly). This star, designated Sigma1 Cancri B, has an estimated 62% of the mass of the Sun.[1]

References

  1. ^ De Rosa, R. J. et al. (2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society. 437 (2): 1216, arXiv:1311.7141. Bibcode:2014MNRAS.437.1216D. doi:10.1093/mnras/stt1932. S2CID 88503488
  2. ^ Guetter, H. H. & Hewitt, A. V. (1984), "Photoelectric UBV photometry for 317 PZT and VZT stars", Astronomical Society of the Pacific. 96: 441–443, Bibcode:1984PASP...96..441G. doi:10.1086/131362
  3. ^
  4. ^ Gaia Collaboration (May 2022), "Gaia Data Release 3 (Gaia DR3). Part 1. Main source", VizieR On-line Data Catalog: I/355. Originally published in: doi:10.1051/0004-63, Bibcode:2022yCat.1355....0G. doi:10.26093/cds/vizier.1355
  5. ^ Zorec, J. & Royer, F. (January 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
  6. ^ Barry, Don C. (January 1970), "Spectral Classification of a and F Stars", Astrophysical Journal Supplement. 19: 281, Bibcode:1970ApJS...19..281B. doi:10.1086/190209
  7. ^ David, Trevor J. & Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal. 804 (2): 146, arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607
  8. ^ Stassun, Keivan G. et al. (2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467
  9. ^ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal. 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M. doi:10.1086/323920