Omicron Pegasi
Star in the constellation Pegasus
title: "Omicron Pegasi" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["a-type-subgiants", "am-stars", "astrometric-binaries", "pegasus-(constellation)", "bayer-objects", "durchmusterung-objects", "flamsteed-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects", "population-i-stars"] description: "Star in the constellation Pegasus" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Omicron_Pegasi" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Star in the constellation Pegasus ::
| image = |image=Pegasus constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=ο Pegasi |x=500|y=275 | caption = Location of ο Pegasi (circled in red) | epoch = J2000 | constell = Pegasus | ra = | dec = | appmag_v = +4.80 | type = | class = A1 IV | b-v = | u-b = +0.035 | variable = | radial_v = | prop_mo_ra = −0.106 | prop_mo_dec = −31.691 | parallax = 11.4116 | p_error = 0.4055 | parallax_footnote = | absmag_v = −0.01 | mass = 2.24 | radius = | gravity = | luminosity = | temperature = | metal_fe = | rotational_velocity = | age_myr = 184 | names = | Simbad=omi+Peg
ο Pegasi, Latinized as Omicron Pegasi, is a suspected astrometric binary star system in the northern constellation of Pegasus. It is white in hue and visible to the naked eye as a faint point of light with an apparent visual magnitude of +4.80. The distance to this system is approximately 290 light years based on parallax, and it is drifting further away from the Sun with a radial velocity of +8.5 km/s.
The visible component has a stellar classification of A1 IV, matching a subgiant star that has begun to cool, expand and brighten off the main sequence. It has very narrow lines due to a low projected rotational velocity of 6 km/s. The abundances of iron are Sun-like, while it displays an overabundance of heavier elements. Some studies have suggested it is an Am-like star. Omicron Pegasi is an estimated 184 million years old with 2.24 times the mass of the Sun. It is radiating 85 times the Sun's luminosity from its photosphere at an effective temperature of 9,600 K.
References
| title=omi Peg | access-date=2019-10-10 }}
| last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869–879 | date=September 2008 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | bibcode=2008MNRAS.389..869E | postscript=. | arxiv=0806.2878 | s2cid=14878976 }}
| title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | arxiv=1108.4971 | doi=10.1134/S1063773712050015 | s2cid=119257644 }}
| last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A. | title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets | journal=The Astrophysical Journal | volume=804 | issue=2 | pages=146 | year=2015 | bibcode=2015ApJ...804..146D | arxiv=1501.03154 | doi=10.1088/0004-637X/804/2/146 | s2cid=33401607 }}
| last=Mermilliod | first=J.-C. | title=Compilation of Eggen's UBV data, transformed to UBV (unpublished) | journal=Catalogue of Eggen's UBV Data | date=1986 | bibcode=1986EgUBV........0M }}
| title=Precise Rotation Rates for Five Slowly Rotating a Stars | last1=Gray | first1=David F. | journal=The Astronomical Journal | volume=147 | issue=4 | id=81 | pages=13 | date=April 2014 | doi=10.1088/0004-6256/147/4/81 | bibcode=2014AJ....147...81G | s2cid=121928906 }}
References
- {{cite DR2. 1887488288069207168
- (2023-12-11). "Non-LTE abundance analysis of A-B stars with low rotational velocities – II. Do A-B stars with normal abundances exist?". Monthly Notices of the Royal Astronomical Society.
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