Sigma Persei

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title: "Sigma Persei" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["bayer-objects", "perseus-(constellation)", "k-type-giants", "flamsteed-objects", "hipparcos-objects", "bright-star-catalogue-objects", "henry-draper-catalogue-objects", "durchmusterung-objects", "suspected-variables"] description: "Star in the constellation Perseus" topic_path: "general/bayer-objects" source: "https://en.wikipedia.org/wiki/Sigma_Persei" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star in the constellation Perseus ::

| name = σ Persei |image= |image=Perseus constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=Sigma Persei |x=521|y=471 |caption=Location of σ Persei (circled) | epoch = J2000 | constell = Perseus | ra = | dec = | appmag_v = 4.36 | type = horizontal branch | class = K3III | b-v = +1.35 | u-b = +1.54 | radial_v = | prop_mo_ra = +3.954 | prop_mo_dec = +18.968 | pm_footnote = | parallax = 9.5060 | p_error = 0.2003 | parallax_footnote = | absmag_v = −0.85 | mass = 1.32 | radius = 36.89 | temperature = 4,165 | luminosity = 368 | rotational_velocity = 2.2 | gravity = 1.46 | metal_fe = −0.20 | age_gyr = 6.6 | names = | Simbad = Sigma+Persei

::figure[src="https://upload.wikimedia.org/wikipedia/commons/f/fe/Sigma_Persei.jpg" caption="σ Persei in optical light"] ::

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

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.

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. However, a 2025 study found that the observed radial velocity variations are intrinsic to the star, and not caused by a planetary companion.

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.{{cite book | last=Allen | first=R. H. | date=1963 | authorlink=Richard Hinckley Allen | title=Star Names: Their Lore and Meaning | url=https://archive.org/details/starnamestheirlo00alle/page/331 | accessdate=2012-09-04 | edition=Reprint | publisher=Dover Publications Inc. | location=New York | isbn=0-486-21079-0 | page=331 | url-access=registration

References

References

1. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues.
2. (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.
3. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters.
4. (2015). "Precise radial velocities of giant stars". Astronomy & Astrophysics.
5. (2007). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics.
6. [https://web.archive.org/web/20140330041910/http://www.astrostudio.org/xhip.php?hip=16335 Sigma Persei (HIP 16335)]
7. (2014). "PLANETARY COMPANION IN K GIANT σ PERSEI". Journal of the Korean Astronomical Society.
8. "* sig Per".
9. {{Cite Gaia DR3. 249147311932147072
10. (2025). "Precise radial velocities of giant stars. XVII. Distinguishing planets from intrinsically induced radial velocity signals in evolved stars". Astronomy & Astrophysics.

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