IC 2391 is a young, nearby open cluster approximately centered on the
bright star o Velorum (
=
,
=
, J2000). Hogg (1960) and
Lynga (1961) have
obtained proper motions and photometry for the brighter members of this
cluster, while spectroscopic data for these brighter members
(
) were presented by Feinstein (1961),
Buscombe (1965),
Perry & Bond (1969),
Levato & Malaroda (1984) and Levato et al. (1988).
These observations have shown that the cluster upper main-sequence contains
approximately 22 members with spectral types earlier than mid-F. The
apparent magnitudes and positions of these stars in the (V,B-V)
diagram are consistent with IC 2391 having a distance of order 150 pc and
an age of order 
yr. More recently, Stauffer et al.
(1989) identified 10 late-type members with spectral types in the range
.