Adaptive optics corrected images obtained with the CIAO instrument at the
Subaru 8.2-meter telescope show the presence of two subarsecond companions to
the nearby (d=19.3 pc) young star GJ 900, which was previously classified as a
single member of the IC 2391 supercluster. The two companions share the same
proper motion as the primary and are redder. Their projected separations from
the primary are 10 AU and 14.5 AU for B and C, respectively. The estimated
masses for the two new companions depend strongly on the age of the system. For
the range of ages found in the literature for IC 2391 supercluster members
(from 35 Myr to 200 Myr), the expected masses range from 0.2 Mββ to 0.4
Mββ for the B component, and from 0.09 Mββ to 0.22 Mββ for
the C component. The determination of the dynamical mass of the faintest
component of GJ 900 will yield the age of the system using theoretical
evolutionary tracks. The apparent separations of the GJ 900 system components
meet the observational criterion for an unstable Trapezium-type system, but
this could be a projection effect. Further observations are needed to establish
the nature of this interesting low-mass multiple system.Comment: Scheduled for publication in the Astronomical Journal (August 2003