Article · Wikipedia archive · Last revised Jun 14, 2026

Sigma Persei

Sigma Persei is an orange K-type giant star with an apparent magnitude of +4.36. It is approximately 343 light-years from Earth.

Last revised
Jun 14, 2026
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σ Persei
Location of σ Persei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 03h 30m 34.48537s1
Declination +47° 59′ 42.7789″1
Apparent magnitude (V) 4.362
Characteristics
Evolutionary stage horizontal branch3
Spectral type K3III4
U−B color index +1.542
B−V color index +1.352
Astrometry
Radial velocity (Rv)+14.32±0.151 km/s
Proper motion (μ) RA: +3.954 mas/yr1
Dec.: +18.968 mas/yr1
Parallax (π)9.5060±0.2003 mas1
Distance343 ± 7 ly
(105 ± 2 pc)
Absolute magnitude (MV)−0.855
Details
Mass1.323 M☉
Radius36.893 R☉
Luminosity3683 L☉
Surface gravity (log g)1.463 cgs
Temperature4,1653 K
Metallicity [Fe/H]−0.203 dex
Rotational velocity (v sin i)2.26 km/s
Age6.63 Gyr
Other designations
σ Per, 35 Per, NSV 1167, BD+47 843, FK5 124, GC 4158, HD 21552, HIP 16335, HR 1052, SAO 38890, PPM 462577
Database references
SIMBADdata
σ Persei in optical light source ↗

Sigma Persei (Sigma Per, σ Persei, σ Per) is an orange K-type giant star4 with an apparent magnitude of +4.36.2 It is approximately 343 light-years from Earth.1

Sigma Persei is moving through the Galaxy at a speed of 17.4 km/s relative to the Sun. Its projected Galactic orbit carries it between 24,400 and 43,600 light years from the center of the Galaxy. It came closest to the Sun 5.1 million years ago when it had brightened to magnitude 3.11 from a distance of 202 light years.8

In 2014 a planet was reported, Sigma Persei b, with a period of 580 days and a mass approximately 6.5 times that of Jupiter.9 However, a 2025 study found that the observed radial velocity variations are intrinsic to the star, and not caused by a planetary companion.10

Name and etymology

This star, together with δ Per, ψ Per, α Per, γ Per and η Per, has been called the Segment of Perseus.11

References

References

  1. 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.
  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. Reffert, Sabine; Bergmann, Christoph; Quirrenbach, Andreas; Trifonov, Trifon; Künstler, Andreas (2015). "Precise radial velocities of giant stars". Astronomy & Astrophysics. 574: A116. arXiv:1412.4634. Bibcode:2015A&A...574A.116R. doi:10.1051/0004-6361/201322360. hdl:10722/215277. S2CID 59334290. Vizier catalog entry
  4. Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  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. S2CID 119257644. Vizier catalog entry
  6. Hekker, S.; Meléndez, J. (2007). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics. 475 (3): 1003. arXiv:0709.1145. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233.
  7. "* sig Per". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2 April 2025.
  8. Sigma Persei (HIP 16335)
  9. Lee, Byeong-Cheol; Han, Inwoo; Park, Myeong-Gu; Mkrtichian, David E.; Jeong, Gwanghui; Kim, Kang-Min; Valyavin, Gennady (2014). "PLANETARY COMPANION IN K GIANT σ PERSEI". Journal of the Korean Astronomical Society. 47 (2): 69. arXiv:1405.2130. Bibcode:2014JKAS...47...69L. doi:10.5303/JKAS.2014.47.2.69.
  10. Spaeth, Dane; Reffert, Sabine; Trifonov, Trifon; Kaminski, Adrian; Albrecht, Simon; Grundahl, Frank; Fredslund Andersen, Mads; Quirrenbach, Andreas; Pallé, Pere L. (2025). "Precise radial velocities of giant stars. XVII. Distinguishing planets from intrinsically induced radial velocity signals in evolved stars". Astronomy & Astrophysics. arXiv:2504.09087. doi:10.1051/0004-6361/202453500.
  11. Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc. p. 331. ISBN 0-486-21079-0. Retrieved 2012-09-04. {{cite book}}: ISBN / Date incompatibility (help)