Lambda Geminorum

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

::summary Star in the constellation Gemini ::

| name = λ Geminorum | image= |image=Gemini constellation map.svg|alt=|float=center|width=300 |mark=Red circle.svg|mark_width=10|mark_link=Zeta Geminorum|x=376|y=538 |caption=Location of λ Geminorum (circled) | epoch = J2000.0 | constell = Gemini | ra = | dec = | appmag_v = 3.571 | type = | class = A3V | r-i = | v-r = | b-v = +0.113 | u-b = +0.167 | variable = Constant | radial_v = –7.40 | prop_mo_ra = –44.43 | prop_mo_dec = –36.61 | parallax = 32.33 | p_error = 0.20 | parallax_footnote = | absmag_v = +1.13 | mass = 2.098 | radius = | gravity = | metal_fe = | temperature = | luminosity = | rotational_velocity = 154 | age_gyr = 0.8 Gyr 0.5 | names = | Simbad = lam+Gem

Lambda Geminorum, Latinized from λ Geminorum, is a candidate multiple star system in the constellation Gemini. It is visible to the naked eye at night with a combined apparent visual magnitude of 3.57. The distance to this system is 101 light years based on parallax, and it is drifting closer with a radial velocity of –7.4 km/s. It is a member of what is suspected to be a trailing tidal tail of the Hyades Stream.

Components A and B of this system form a wide binary. The secondary, component B, is a magnitude 10.7 stellar companion at an angular separation of from the primary along a position angle of 35.72°, as of 2009. The primary was identified as a spectroscopic binary by E. B. Frost in 1924. This companion was confirmed during a lunar occultation with a separation of and magnitude 6.8.

The primary, designated component A, typically has been assigned a stellar classification of A3V, which indicates this is an A-type main-sequence star that generates energy from core hydrogen fusion. However, in 1970 D. C. Barry classed it as A4IV, suggesting this may be a subgiant star that has begun evolving into a giant star. It was catalogued a suspected variable star, but is now confirmed as constant.

This star is less than a billion years in age with a rapid spin, showing a projected rotational velocity of 154 km/s It is larger and hotter than the Sun, with twice the Sun's mass and 2.8 times the radius of the Sun. The star is radiating 27 times the Sun's luminosity from its photosphere at an effective temperature of 7,932 K.

The primary displays a significant infrared excess in the K-band, which indicates an orbiting circumstellar disk of dust. A model fit to the data shows an inner radius between and , and an outer radius of up to .

References

| title=Spectral Classification of a and F Stars | last=Barry | first=Don C. | postscript=. | journal=Astrophysical Journal Supplement | volume=19 | page=281 | date=January 1970 | doi=10.1086/190209 | bibcode=1970ApJS...19..281B }}

| title=Fourteen spectroscopic binaries | last=Frost | first=E. B. | postscript=. | journal=Astrophysical Journal | volume=60 | pages=319–320 | date=December 1924 | doi=10.1086/142868 | bibcode=1924ApJ....60..319F }}

| title=New binary stars discovered by lunar occultations. IV | last1=Richichi | first1=A. | last2=Ragland | first2=S. | last3=Calamai | first3=G. | last4=Baffa | first4=C. | last5=Stecklum | first5=B. | last6=Richter | first6=S. | display-authors=1 | journal=Astronomy and Astrophysics | volume=350 | pages=491−496 | date=October 1999 | bibcode=1999A&A...350..491R | postscript=. }}

| display-authors=1 | last1=Rodriguez | first1=David R. | last2=Duchêne | first2=Gaspard | last3=Tom | first3=Henry | last4=Kennedy | first4=Grant M. | last5=Matthews | first5=Brenda | last6=Greaves | first6=Jane | last7=Butner | first7=Harold | title=Stellar multiplicity and debris discs: an unbiased sample | journal=Monthly Notices of the Royal Astronomical Society | volume=449 | issue=3 | pages=3160–3170 | date=May 2015 | doi=10.1093/mnras/stv483 | doi-access=free | arxiv=1503.01320 | bibcode=2015MNRAS.449.3160R | s2cid=119237891 | postscript=. }}

| title=Utilizing Synthetic UV Spectra to Explore the Physical Basis for the Classification of Lambda Boötis Stars | display-authors=1 | last1=Cheng | first1=Kwang-Ping | last2=Neff | first2=James E. | last3=Johnson | first3=Dustin M. | last4=Tarbell | first4=Erik S. | last5=Romo | first5=Christopher A. | last6=Prabhaker | first6=Arvind | last7=Steele | first7=Patricia A. | last8=Gray | first8=Richard O. | last9=Corbally | first9=Christopher J. | journal=The Astronomical Journal | postscript=. | volume=151 | issue=4 | id=105 | pages=17 | date=April 2016 | doi=10.3847/0004-6256/151/4/105 | bibcode=2016AJ....151..105C | s2cid=124045100 | doi-access=free }}

| title=Constraints on the structure of hot exozodiacal dust belts | display-authors=1 | last1=Kirchschlager | first1=Florian | last2=Wolf | first2=Sebastian | last3=Krivov | first3=Alexander V. | last4=Mutschke | first4=Harald | last5=Brunngräber | first5=Robert | journal=Monthly Notices of the Royal Astronomical Society | volume=467 | issue=2 | pages=1614–1626 | date=May 2017 | arxiv=1701.07271 | bibcode=2017MNRAS.467.1614K | doi=10.1093/mnras/stx202 | doi-access=free | postscript=. }}

| title=Hyades tidal tails revealed by Gaia DR2 | display-authors=1 | last1=Röser | first1=Siegfried | last2=Schilbach | first2=Elena | last3=Goldman | first3=Bertrand | journal=Astronomy & Astrophysics | volume=621 | id=L2 | pages=5 | date=January 2019 | arxiv=1811.03845 | bibcode=2019A&A...621L...2R | doi=10.1051/0004-6361/201834608 | s2cid=118909033 | postscript=. }}

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

| 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 | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644 | postscript=. }}

| title=Stellar Diameters and Temperatures. III. Main-sequence A, F, G, and K Stars: Additional High-precision Measurements and Empirical Relations | last1=Boyajian | first1=Tabetha S. | last2=von Braun | first2=Kaspar | last3=van Belle | first3=Gerard | last4=Farrington | first4=Chris | last5=Schaefer | first5=Gail | last6=Jones | first6=Jeremy | last7=White | first7=Russel | last8=McAlister | first8=Harold A. | last9=ten Brummelaar | first9=Theo A. | last10=Ridgway | first10=Stephen | last11=Gies | first11=Douglas | last12=Sturmann | first12=Laszlo | last13=Sturmann | first13=Judit | last14=Turner | first14=Nils H. | last15=Goldfinger | first15=P. J. | last16=Vargas | first16=Norm | display-authors = 1 | journal=The Astrophysical Journal | volume=771 | issue=1 | page=40 | date=July 2013 | arxiv=1306.2974 | doi=10.1088/0004-637X/771/1/40 | bibcode=2013ApJ...771...40B | s2cid=14911430 }}

| title=Rotational velocities of A-type stars. III. Velocity distributions | display-authors=1 | last1=Royer | first1=F. | last2=Zorec | first2=J. | last3=Gómez | first3=A. E. | journal=Astronomy and Astrophysics | volume=463 | issue=2 | pages=671–682 | date=February 2007 | doi=10.1051/0004-6361:20065224 | s2cid=18475298 | bibcode=2007A&A...463..671R | arxiv=astro-ph/0610785 }}

| title=A System of photometric standards | display-authors=1 | last1=Gutierrez-Moreno | first1=Adelina | last2=Moreno | first2=H. | last3=Stock | first3=J. | last4=Torres | first4=C. | last5=Wroblewski | first5=H. | journal=Publications of the Department of Astronomy University of Chile | publisher=Publicaciones Universidad de Chile, Department de Astronomy | volume=1 | pages=1–17 | year=1966 | bibcode=1966PDAUC...1....1G | postscript=. }}

| last1=Gontcharov | first1=G. A. | title=Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system | journal=Astronomy Letters | postscript=. | volume=32 | issue=11 | pages=759–771 | date=November 2006 | doi=10.1134/S1063773706110065 | s2cid=119231169 | bibcode=2006AstL...32..759G | arxiv=1606.08053 }}

| title=* lam Gem | accessdate=2006-12-09 }}

| title=Lam Gem | url = http://www.aavso.org/vsx/index.php?view=detail.top&oid=42136 | work=The International Variable Star Index | publisher=AAVSO – American Association of Variable Star Observers | accessdate=March 29, 2017 }}

References

1. {{cite DR2. 3168265196643176832

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