Program: GN-2013A-Q-96

With the AO-equipped NIRI instrument, we propose to obtain follow-up confirmation imaging of candidate substellar and degenerate companions to young, nearby A-stars discovered as a part of the two large-scale surveys: the IDPS (International Deep Planet Search) and VAST (Volume-limited A-STar) Surveys. The candidate substellar companions have masses covering the planet/brown dwarf transition (7 – 45 Mjup) at well-determined young ages between ~30 and 400 Myrs and confirmed objects will serve as important benchmarks against which theoretical evolutionary and atmospheric models can be tested. Any confirmed substellar companions would cover either important intermediate ages or particularly low masses compared to isolated field brown dwarfs. The final target has an unusual pair of candidate co-moving objects that are potential white dwarfs, and would present a unique system of a quadruple composed of an A-star binary surrounded by a circumbinary debris disk with a wide pair of exceptionally young white dwarfs. This degenerate system would be another example of a Sirius B-type system, though unusual in containing two degenerate objects and a debris disk. In summary, the proposed observations are the critical follow-up measurements require to: estimate the frequency of wide orbit planetary mass and brown dwarf companions, and confirm the nature of a unique young quadruple system with a pair of white dwarfs.