Upsilon2 Eridani

---

title: "Upsilon2 Eridani" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["g-type-giants", "horizontal-branch-stars", "eridanus-(constellation)", "stars-with-proper-names", "bayer-objects", "durchmusterung-objects", "flamsteed-objects", "henry-draper-catalogue-objects", "hipparcos-objects", "bright-star-catalogue-objects"] description: "Star in the constellation of Eridanus" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Upsilon2_Eridani" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star in the constellation of Eridanus ::

| name = υ2 Eridani}} | image= |image=Eridanus constellation map.svg|alt=|float=center|width=240 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=υ² Eridani |x=310|y=631 |caption=Location of υ2 Eridani (circled) | epoch = J2000.0 | equinox = J2000.0 (ICRS) | constell = Eridanus | ra = | dec = | appmag_v = 3.804 | type = Red clump | class = G8+ III | u-b = +0.740 | b-v = +0.968 | r-i = | radial_v = | prop_mo_ra = | prop_mo_dec = | pm_footnote = | parallax = 15.4501 | p_error = 0.1081 | parallax_footnote = | absmag_v= | source = | mass = | radius = | luminosity = | temperature = | gravity = | metal_fe = | rotational_velocity = | age_gyr = | names= Theemin, υ2 Eridani, Upsilon2 Eridani, 52 Eridani, CD−30°1901, CPD−30°631, FK5 170, GC 5614, HD 29291, HIP 21393, HR 1464, PPM 280424, SAO 195148 | Simbad=ups02+eri}}

Upsilon2 Eridani (υ² Eridani, abbreviated Upsilon2 Eri, υ2 Eri), officially named Theemin ,{{cite book |last1=Kunitzsch |first1=Paul |last2=Smart |first2=Tim |date = 2006 |edition = 2nd rev. |title = A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations |publisher = Sky Pub |location = Cambridge, Massachusetts |isbn = 978-1-931559-44-7

It is an evolved red clump giant star with a stellar classification of G8+ III. The star has 3.15 times the Sun's mass and 14.09 times the Sun's radius. It radiates 114 times the solar luminosity from its outer atmosphere at an effective temperature of 5,023 K.

Nomenclature

υ2 Eridani (Latinised to Upsilon2 Eridani) is the star's Bayer designation.

It bore the traditional name Theemin (also written as Theemim and Beemin). to catalogue and standardize proper names for stars. The WGSN approved the name Theemin for this star on February 1, 2017, and it is now included in the List of IAU-approved Star Names.

In the Almagest, Ptolemy called it hē kampē, "the bend in the river;" Arab writers corrupted this to bhmn, later becoming beemin, beemun in the West. Subsequently, its etymology was incorrectly derived from Hebrew תאומים (te'omim), meaning "twins," producing Theemin.

In Chinese, 天園 (Tiān Yuán), meaning Celestial Orchard, refers to an asterism consisting of Upsilon2 Eridani, Chi Eridani, Phi Eridani, Kappa Eridani, HD 16754, HD 23319, Theta Eridani, HD 24072, HD 24160, Upsilon4 Eridani, Upsilon3 Eridani and Upsilon1 Eridani. Consequently, the Chinese name for Upsilon2 Eridani itself is 天園十二 (Tiān Yuán shíèr, ).

References

| title=The Oxford Handbook of Names and Naming | editor1-first=Carole | editor1-last=Hough | publisher=Oxford University Press | year=2016 | isbn=978-0191630422 | page=762 | url=https://books.google.com/books?id=B8LQCwAAQBAJ&pg=PT762 | postscript=. }}

| first1=P. | last1=Keenan | first2=R. | last2=McNeil | title=The Perkins catalog of revised MK types for the cooler stars | journal=Astrophysical Journal Supplement Series | volume=71 | pages=245–266 | date=October 1989 | bibcode=1989ApJS...71..245K | doi=10.1086/191373 | postscript=. }}

| last1=de Bruijne | first1=J. H. J. | last2=Eilers | first2=A.-C. | title=Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project | journal=Astronomy & Astrophysics | volume=546 | id=A61 | pages=14 | date=October 2012 | doi=10.1051/0004-6361/201219219 | bibcode=2012A&A...546A..61D | arxiv=1208.3048 | s2cid=59451347 | postscript=. }}

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

| last1=Alves | first1=David R. | title=K-Band Calibration of the Red Clump Luminosity | journal=The Astrophysical Journal | volume=539 | issue=2 | pages=732–741 | date=August 2000 | doi=10.1086/309278 | bibcode=2000ApJ...539..732A | arxiv=astro-ph/0003329 | s2cid=16673121 | postscript=. }}

| title=ups02 Eri -- Star | work=SIMBAD Astronomical Database | publisher=Centre de Données astronomiques de Strasbourg | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=ups02+Eri | access-date=2016-10-13 | postscript=. }}

References

1. "Naming Stars". IAU.org.
2. "International Astronomical Union {{!}} IAU".
3. "Theemin".
4. Hough, Carole. (May 3, 2016). "The Oxford Handbook of Names and Naming". Oxford University Press.
5. {{in lang. zh ''中國星座神話'', written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN. 978-986-7332-25-7.
6. {{in lang. zh [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_t_z.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive. link. (2010-08-19 , Hong Kong Space Museum. Accessed on line November 23, 2010.)
7. (2022-01-01). "CORALIE radial-velocity search for companions around evolved stars (CASCADES). I. Sample definition and first results: Three new planets orbiting giant stars". Astronomy and Astrophysics.
8. {{cite DR3. 4878631812268014464

::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. ::