Gamma Lupi

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title: "Gamma Lupi" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["b-type-subgiants", "triple-star-systems", "upper-centaurus-lupus", "lupus-(constellation)", "bayer-objects", "durchmusterung-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects"] description: "Triple star system in the constellation Lupus" topic_path: "general/b-type-subgiants" source: "https://en.wikipedia.org/wiki/Gamma_Lupi" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Triple star system in the constellation Lupus ::

| image = | image=Lupus IAU.svg | float=center | width=240 | position=right | mark=Red circle.svg | mark_width=10 | mark_link=γ Lup | x%=43.1 | y%=44.5 | caption = Location of γ Lupi (circled) | epoch = J2000.0 | constell = Lupus | ra = | dec = | appmag_v = 2.77 | class = B2 IV | b-v = −0.20 | u-b = −0.82 | variable = | radial_v = +2.3 | prop_mo_ra = −15.62 | prop_mo_dec = −25.43 | parallax = 7.75 | p_error = 0.50 | parallax_footnote = | absmag_v = −2.4 | primary = Aa | name = Ab | reference = | period_unitless = 2.85 days | axis_unitless = | eccentricity = 0 | k1 = | primary = A | name = B | reference = | period = | axis = | axis_unitless = | eccentricity= | inclination = | node = | periastron = | periarg = | source = | component1 = γ Lup Aa | mass = | radius = | luminosity = | gravity = | age_myr = | temperature = 20,900 | rotational_velocity = 270 | component2 = γ Lup Ab | mass2 = | luminosity2 = | radius2 = | temperature2= | gravity2 = | names = | Simbad = gam+Lup

Gamma Lupi, Latinized from γ Lupi, is a triple star system in the constellation of Lupus. It is easily visible to the naked eye, having an apparent magnitude of 2.77. It is also known in ancient Chinese astronomy as 騎官一 or "the 1st (star) of the Cavalry Officer". With a telescope, Gamma Lupi can be resolved into a binary star system in close orbit. This is known as the Gamma Lupi AB system, often abbreviated as γ Lupi AB or γ Lup AB.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/3/32/GammaLupLightCurve.png" caption="TESS]]'' data"] ::

The system has a hierarchical architecture. The primary, Gamma Lupi A is itself a spectroscopic binary with an orbital period of 2.849769 days. Although the system does not show eclipses, the hotter star of the pair heats the side of the cooler star that faces it, and as they orbit each other the combined starlight varies in brightness by about 0.02 magnitudes, as seen from the Earth. The outer component, Gamma Lupi B, is widely-separated (125 astronomical units) and has an orbital period of 170 years.

This star is a proper motion member of the Upper Centaurus–Lupus sub-group in the Scorpius–Centaurus OB association, the nearest such co-moving association of massive stars to the Sun.

References

References

1. van Leeuwen, F.. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics.
2. "gam Lup". AAVSO.
3. (June 1989). "Physical parameters of stars in the Scorpio-Centaurus OB association". Astronomy and Astrophysics.
4. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute.
5. (June 2021). "BRITE observations of ν Centauri and γ Lupi, the first non-eclipsing members of the new class of nascent binaries". Monthly Notices of the Royal Astronomical Society.
6. "* gam Lup".
7. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". [[Monthly Notices of the Royal Astronomical Society]].
8. Evans, D. S.. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". [[International Astronomical Union]].
9. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago.
10. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::