Lambda Eridani variable

A Lambda Eridani Variable is a class of Be stars that show small amplitude variations of a few hundredths of a magnitude. The variations are highly regular with periods between 0.5 and 2.0 days, and they were initially described as periodic Be stars.{{cite journal|bibcode=1995MNRAS.277.1547B|title=Tests of the Pulsation and Starspot Models for the Periodic Be-Stars|journal=Monthly Notices of the Royal Astronomical Society|volume=277|issue=4|pages=1547–1554|last1=Balona|first1=L. A|year=1995|doi=10.1093/mnras/277.4.1547|doi-access=free}} Lambda Eridani is an example and the prototype. This has been ascribed to non-radial pulsations, inhomogeneous rotating discs, or the rotation of the star itself.{{cite journal|bibcode=2011AcA....61..247J|arxiv=1110.4064|title=A CCD Search for Variable Stars of Spectral Type B in the Northern Hemisphere Open Clusters. VIII. NGC 6834|journal=Acta Astronomica|volume=61|pages=247–273|last1=Jerzykiewicz|first1=M.|last2=Kopacki|first2=G.|last3=Pigulski|first3=A.|last4=Kołaczkowski|first4=Z.|last5=Kim|first5=S.-L.|year=2011|issue=3}}{{cite journal|doi=10.1051/0004-6361:20020174|title=Search for duplicity in periodic variable Be stars|journal=Astronomy and Astrophysics|volume=385|issue=2|pages=488|year=2002|last1=Carrier|first1=F.|last2=Burki|first2=G.|last3=Burnet|first3=M.|bibcode = 2002A&A...385..488C |doi-access=free}}

These stars are rarely classified, or are classified incorrectly. The General Catalogue of Variable Stars does not have a type for λ Eridani variables, only GCAS for Gamma Cassiopeiae variables and BE for non-GCAS Be star variables. λ Eridani itself is incorrectly listed as a Beta Cephei variable.{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}} The AAVSO International Variable Star Index defines a LERI type of variability, with 51 stars included as λ Eri variables, 16 of them only suspected, and 32 combined with other types of variation.{{cite web|url=https://www.aavso.org/vsx/index.php?view=about.vartypes|title=Variable Star Type Designations in the VSX|last1=Otero|first1=S. A. |last2=Watson |first2=C. |last3=Wils |first3=P. |work=AAVSO Website|publisher=American Association of Variable Star Observers|accessdate=19 July 2014}}{{cite journal|bibcode=2015yCat....102027W|title=VizieR Online Data Catalog: AAVSO International Variable Star Index VSX (Watson+, 2006-)|journal=VizieR On-line Data Catalog: B/VSX. Originally Published in: 2006SASS...25...47W|volume=1|display-authors=etal|last1=Watson|first1=C. |last2=Henden|first2=A. A.|date=2022 |url=https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-ref=VIZ65eb3c8c3268a7&-to=-4b&-from=-3&-this=-4&%2F%2Fsource=B%2Fvsx%2Fvsx&%2F%2Ftables=B%2Fvsx%2Fvsx&-out.max=1000&%2F%2FCDSportal=http%3A%2F%2Fcdsportal.u-strasbg.fr%2FStoreVizierData.html&-out.form=HTML+Table&-out.add=_r&%2F%2Foutaddvalue=default&-sort=_r&-order=I&-oc.form=sexa&-out.src=B%2Fvsx%2Fvsx&-nav=cat%3AB%2Fvsx%26tab%3A%7BB%2Fvsx%2Fvsx%7D%26key%3Asource%3DB%2Fvsx%2Fvsx%26HTTPPRM%3A&-c=&-c.eq=J2000&-c.r=++2&-c.u=arcmin&-c.geom=r&-source=&-source=B%2Fvsx%2Fvsx&-out.orig=standard&-out=OID&-out=n_OID&-out=Name&-out=V&-out=Type&Type=*LERI*&-out=l_max&-out=max&-out=u_max&-out=n_max&-out=f_min&-out=l_min&-out=min&-out=u_min&-out=n_min&-out=l_Period&-out=Period&-out=u_Period&-out=Sp&-out=RAJ2000&-out=DEJ2000&-meta.ucd=2&-meta=1&-meta.foot=1&-usenav=1&-bmark=GET |access-date=8 March 2024}}