Lambda2 Fornacis
Binary star system in the constellation Fornax
title: "Lambda2 Fornacis" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["g-type-main-sequence-stars", "solar-analogs", "planetary-systems-with-one-confirmed-planet", "binary-stars", "fornax", "bayer-objects", "durchmusterung-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects"] description: "Binary star system in the constellation Fornax" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Lambda2_Fornacis" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Binary star system in the constellation Fornax ::
| name = Lambda2 Fornacis
| image = [[File:Fornax dwarf galaxy.jpg|250px]]
| caption = λ2 Fornacis on the right of the Fornax Dwarf Galaxy
| credit = ESO/Digitized Sky Survey 2
| epoch = J2000.0
| constell = Fornax
| ra =
| dec =
| appmag_v = 5.78
| type =
| class = G1V
| b-v =
| variable =
| radial_v =
| prop_mo_ra =
| prop_mo_dec =
| pm_footnote =
| parallax = 39.2946
| p_error = 0.0305
| parallax_footnote =
| absmag_v =
| component1 = A
| mass =
| radius =
| gravity =
| metal_fe =
| luminosity = 3.03
| temperature =
| rotational_velocity = 1.4 or 3.2
| age_gyr =
| component2 = B
| mass2 = 0.11
| names =
| Simbad = lam02+For
| ARICNS = 00227
| NSTED = HD+16417
| EPE = HD+16417
λ2 Fornacis, Latinized as Lambda2 Fornacis, is the primary of a binary star system in the southern constellation of Fornax. It is just visible to the naked eye as a dim, yellow-hued point of light with an apparent visual magnitude of 5.78. It is located 83 light years distant from the Sun, based on stellar parallax, and is drifting further away with a radial velocity of +11.1 km/s.
This object is a G-type main-sequence star with a stellar classification of G1V.
There is a faint co-moving companion star located to the east of the main star at an angular separation of . This is most likely an M5–M6 class red dwarf with 0.11 times the Sun's mass. The projected separation between the pair is about .
Planetary system
Precision Doppler spectroscopy from an intensive 48 night observing campaign on the Anglo-Australian Telescope has revealed the presence of a low-mass extrasolar planet orbiting the star. This object has an orbital period of 17.25 days and an eccentricity of 0.14. It has a minimum (baseline) mass of .
| table_ref = | name = Lambda2 Fornacis | exoplanet = b | mass_earth = ≥ | period = | semimajor = | eccentricity =
References
| title=Spectroscopic study of solar twins and analogues | display-authors=1 | last1=Datson | first1=Juliet | last2=Flynn | first2=Chris | last3=Portinari | first3=Laura | journal=Astronomy & Astrophysics | volume=574 | id=A124 | pages=12 | date=February 2015 | bibcode=2015A&A...574A.124D | arxiv=1412.8168 | doi=10.1051/0004-6361/201425000 | s2cid=53708062 }}
| 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=Gray | first1=R. O. | last2=Corbally | first2=C. J. | last3=Garrison | first3=R. F. | last4=McFadden | first4=M. T. | last5=Bubar | first5=E. J. | last6=McGahee | first6=C. E. | last7=O'Donoghue | first7=A. A. | last8=Knox | first8=E. R. | title=Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample | display-authors=1 | journal=The Astronomical Journal | volume=132 | issue=1 | pages=161–170 | date=July 2006 | doi=10.1086/504637 | arxiv=astro-ph/0603770 | bibcode=2006AJ....132..161G | s2cid=119476992 }}
| display-authors=1 | last1=da Silva | first1=L. | last2=Girardi | first2=L. | last3=Pasquini | first3=L. | last4=Setiawan | first4=J. | last5=von der Lühe | first5=O. | last6=de Medeiros | first6=J. R. | last7=Hatzes | first7=A. | last8=Döllinger | first8=M. P. | last9=Weiss | first9=A. | title=Basic physical parameters of a selected sample of evolved stars | journal=Astronomy and Astrophysics | volume=458 | issue=2 | pages=609–623 | date=November 2006 | bibcode=2006A&A...458..609D | arxiv=astro-ph/0608160 | doi=10.1051/0004-6361:20065105 | s2cid=9341088 }}
| title=A Neptune-mass Planet Orbiting the Nearby G Dwarf HD16417 | last1=O’Toole | first1=Simon | last2=Tinney | first2=C. G. | last3=Butler | first3=R. Paul | last4=Jones | first4=Hugh R. A. | last5=Bailey | first5=Jeremy | last6=Carter | first6=Brad D. | last7=Vogt | first7=Steven S. | last8=Laughlin | first8=Gregory | last9=Rivera | first9=Eugenio J. | display-authors=1 | journal=The Astrophysical Journal | volume=697 | issue=2 | pages=1263–1268 | year=2009 | arxiv=0902.4024 | bibcode=2009ApJ...697.1263O | doi=10.1088/0004-637X/697/2/1263 | s2cid=16341718 }}
| title=New wide stellar companions of exoplanet host stars | display-authors=1 | last1=Mugrauer | first1=M. | last2=Ginski | first2=C. | last3=Seeliger | first3=M. | journal=Monthly Notices of the Royal Astronomical Society | volume=439 | issue=1 | pages=1063–1070 | date=March 2014 | doi=10.1093/mnras/stu044 | bibcode=2014MNRAS.439.1063M | doi-access=free }}
| title=Spectroscopic Parameters and atmosphEric ChemIstriEs of Stars (SPECIES). I. Code description and dwarf stars catalogue | last1=Soto | first1=M. G. | last2=Jenkins | first2=J. S. | journal=Astronomy & Astrophysics | volume=615 | id=A76 | pages=28 | date=July 2018 | arxiv=1801.09698 | bibcode=2018A&A...615A..76S | doi=10.1051/0004-6361/201731533 | s2cid=119107228 }}
References
- It is considered a [[solar analog]], being [[Photometry (astronomy). 6.3
- "lam02 For".
- (September 2020). "TESS asteroseismology of the known planet host star ''λ''2 Fornacis". [[Astronomy & Astrophysics]].
- {{Cite Gaia DR3. 5062172841616745856
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