Nu Geminorum

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title: "Nu Geminorum" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["b-type-giants", "shell-stars", "gemini-(constellation)", "bayer-objects", "durchmusterung-objects", "flamsteed-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects", "triple-star-systems"] description: "Star system in the constellation Gemini" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Nu_Geminorum" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star system in the constellation Gemini ::

| name = ν Geminorum | image = |image=Gemini constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=ν Geminorum |x=700|y=432 | caption = Location of ν Geminorum (circled in red) | epoch = J2000.0 | equinox = J2000.0 (ICRS) | constell = Gemini | ra = | dec = | appmag_v = 4.16 | class = B6 III + B8 III | b-v = −0.13 | u-b = −0.47 | r-i = | variable = | radial_v = +39.4 | prop_mo_ra = −6.82 | prop_mo_dec = −13.10 | parallax = 5.99 | p_error = 0.28 | parallax_footnote = | absmag_v = −2.2 + −1.2 | reference = | primary = ν Gem Aa | name = ν Gem Ab | period_unitless = 53.7722 ± 0.0008 d | periastron = MJD 51011.8 ± 0.1 | eccentricity = 0.056 ± 0.003 | periarg = 6.7 ± 2.0 | k1 = 51.6 ± 0.6 | k2 = 52.5 ± 1.1 | inclination = 0.98 ± 0.03 | node = 78.9 ± 0.2 | axis_unitless = 2.82 ± 0.02 mas | reference = | primary = ν Gem A | name = ν Gem B | period_unitless = 6977.3 ± 6.1 | periastron = MJD 48810.3 ± 13.0 | eccentricity = 0.241 ± 0.002 | periarg = 226.9 ± 0.4 | k1 = 8.0 ± 0.1 | k2 = 15.9 ± 0.1 | inclination = 75.9 ± 0.2 | node = 121.0 ± 0.1 | axis_unitless = 82.8 ± 1.3 mas | component1 = ν Gem Aa | mass = 3.34 | radius = | luminosity = 1,380 | temperature = 14,100 | gravity = | metal_fe = | rotational_velocity = 160 | rotation = | age_gyr = | component2 = ν Gem Ab | mass2 = 3.28 | component1 = ν Gem B | mass = 3.33 | names = | Simbad = nu+Gem

Nu Geminorum, Latinized from ν Geminorum, is a triple star system in the constellation Gemini. It has an apparent visual magnitude of 4.16, which is bright enough to be visible to the naked eye on a dark night. Based upon an annual parallax shift of 5.99 mas, it is located at a distance of roughly 540 light years from the Sun. The position of this system near the ecliptic means it is subject to lunar occultations.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/1/11/Nu_Geminorum.jpg" caption="ν Geminorum in optical light"] ::

The inner components of this multiple star system have an orbital period of about 54 days and a nearly circular orbit with an eccentricity of 0.056. There is some uncertainty in the spectral type, with classifications ranging from a main sequence star to a giant. Orbiting the inner pair is a classical Be star, with an orbital period of 19.1 years and an eccentricity of 0.24. The two orbits are co-directional and roughly coplanar. The system is overall dynamically stable, and shows no signs of Kozai-Lidov cycles. The outer Be star appears to be single.

ν Gem together with γ Gem (Alhena), η Gem (Propus), μ Gem (Tejat), and ξ Gem (Alzirr) formed the Arabic asterism Al Nuḥātai, the Camel's Hump; ν Gem being the only one of these stars that is otherwise unnamed. Based on this, the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars listed ν Gem with the name Nucatai.

On 15 August 2028, it will be occulted by Venus over Southern Africa and Madagascar.

References

| title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 | postscript=. }}

| title=Orbits for two short-period and two long-period binaries | last1=Cvetković | first1=Z. | last2=Ninković | first2=S. | journal=New Astronomy | postscript=. | volume=13 | issue=8 | pages=587–592 | date=November 2008 | doi=10.1016/j.newast.2008.03.005 | bibcode=2008NewA...13..587C }}

| display-authors=1 | last1=Hohle | first1=M. M. | last2=Neuhäuser | first2=R. | last3=Schutz | first3=B. F. | title=Masses and luminosities of O- and B-type stars and red supergiants | journal=Astronomische Nachrichten | volume=331 | issue=4 | page=349 | date=April 2010 | doi=10.1002/asna.200911355 | bibcode=2010AN....331..349H | arxiv=1003.2335 | s2cid=111387483 | postscript=. }}

| last=Wilson | first=R. E. | year=1953 | title=General Catalogue of Stellar Radial Velocities | journal=Carnegie Institute Washington D.C. Publication | publisher=Carnegie Institute of Washington D.C. | bibcode=1953GCRV..C......0W | postscript=. }}

| display-authors=1 | last1=Abt | first1=Helmut A. | last2=Levato | first2=Hugo | last3=Grosso | first3=Monica | title=Rotational Velocities of B Stars | journal=The Astrophysical Journal | volume=573 | issue=1 | pages=359–365 | date=July 2002 | doi=10.1086/340590 | bibcode=2002ApJ...573..359A | postscript=. | doi-access=free }}

| display-authors=1 | last1=Crawford | first1=D. L. | last2=Barnes | first2=J. V. | last3=Golson | first3=J. C. | title=Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere | journal=The Astronomical Journal | year=1971 | pages=1058 | volume=76 | bibcode=1971AJ.....76.1058C | doi=10.1086/111220 | postscript=. }}

| title=nu. Gem | accessdate=2016-12-06 | postscript=. }}

| url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720005197_1972005197.pdf | first1=Jack W. | last1=Rhoads | postscript=. | title=Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars | publisher=Jet Propulsion Laboratory | publication-place=California Institute of Technology | date=November 15, 1971 | accessdate=2019-01-09 }}

| title=Photoelectric observations of lunar occultations. XIII | last1=Blow | first1=G. L. | last2=Chen | first2=P. C. | last3=Edwards | first3=D. A. | last4=Evans | first4=D. S. | last5=Frueh | first5=M. | display-authors=1 | journal=Astronomical Journal | postscript=. | volume=87 | pages=1571–1584 | date=November 1982 | doi=10.1086/113247 | bibcode=1982AJ.....87.1571B | doi-access=free }}

| doi=10.3847/1538-4357/ac062c | title=ν Gem: A Hierarchical Triple System with an Outer Be Star | year=2021 | last1=Klement | first1=Robert | last2=Hadrava | first2=Petr | last3=Rivinius | first3=Thomas | last4=Baade | first4=Dietrich | last5=Cabezas | first5=Mauricio | last6=Heida | first6=Marianne | last7=Schaefer | first7=Gail H. | last8=Gardner | first8=Tyler | last9=Gies | first9=Douglas R. | last10=Anugu | first10=Narsireddy | last11=Lanthermann | first11=Cyprien | last12=Davies | first12=Claire L. | last13=Anderson | first13=Matthew D. | last14=Monnier | first14=John D. | last15=Ennis | first15=Jacob | last16=Labdon | first16=Aaron | last17=Setterholm | first17=Benjamin R. | last18=Kraus | first18=Stefan | last19=Ten Brummelaar | first19=Theo A. | last20=Le Bouquin | first20=Jean-Baptiste | journal=The Astrophysical Journal | volume=916 | issue=1 | page=24 | arxiv=2105.13437 | bibcode=2021ApJ...916...24K | s2cid=235247900 | doi-access=free }}

| title=Identification List of Spectroscopic and Eclipsing Binaries Subject to Occultations by the Moon | last=Herr | first=Richard B. | journal=Publications of the Astronomical Society of the Pacific | volume=81 | issue=479 | page=105 | date=April 1969 | doi=10.1086/128748 | bibcode=1969PASP...81..105H }}

References

1. Meeus, Jan. (2002). "More Mathematical Astronomy Morsels".
2. (1899). "Star Names: Their Lore and Meaning".

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