As of 2008, the pair had an angular separation of 12.7″.[3] The brighter member, designated component A, is an aging giant star with a stellar classification of K5III.[4] It is reported as a semi-regular variable with magnitude ranging from 4.68 to 4.72 over 141 days,[6] although the General Catalogue of Variable Stars describes this as unconfirmed by subsequent observations.[7] It has the variable star designationCI Orionis, while 31 Orionis is the Flamsteed designation. The magnitude 10.2 companion star, component B, is an F-type main-sequence star with a class of F7V.[3]
^ abHoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
^ abMermilliod, J. C. (2006). "Homogeneous Means in the UBV System (Mermilliod 1991)". VizieR On-line Data Catalog: II/168. Originally Published in: Institut d'Astronomie. 2168. Bibcode:2006yCat.2168....0M.Vizier catalog entry
^ ab"CI Ori". The International Variable Star. AAVSO – American Association of Variable Star Observers. Retrieved 6 August 2016.
^ abSamus, N. N.; Durlevich, O. V.; et al. (2009). "General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. 1. Bibcode:2009yCat....102025S.