HR8799 is a nearby A-type star with a debris disk and three planetary candidates recently imaged directly .
We undertake a coherent analysis of various portions of observational data on all known components of the system , including the central star , imaged companions , and dust .
The goal is to elucidate the architecture and evolutionary status of the system .
We try to further constrain the age and orientation of the system , orbits and masses of the companions , as well as the location of dust .
From the high luminosity of debris dust and dynamical constraints , we argue for a rather young system ’ s age of \la 50 Myr .
The system must be seen nearly , but not exactly , pole-on .
Our analysis of the stellar rotational velocity yields an inclination of 13 – 30 ^ { \circ } , whereas i \ga 20 ^ { \circ } is needed for the system to be dynamically stable , which suggests a probable inclination range of 20 – 30 ^ { \circ } .
The spectral energy distribution , including the Spitzer/IRS spectrum in the mid-infrared as well as IRAS , ISO , JCMT and IRAM observations , is naturally reproduced with two dust rings associated with two planetesimal belts .
The inner “ asteroid belt ” is located at \sim 10 AU inside the orbit of the innermost companion and a “ Kuiper belt ” at \ga 100 AU is just exterior to the orbit of the outermost companion .
The dust masses in the inner and outer ring are estimated to be \approx 1 \times 10 ^ { -5 } and 4 \times 10 ^ { -2 } Earth masses , respectively .
We show that all three planetary candidates may be stable in the mass range suggested in the discovery paper by Marois et al .
2008 ( between 5 and 13 Jupiter masses ) , but only for some of all possible orientations .
For ( M _ { b } ,M _ { c } ,M _ { d } ) = ( 5 , 7 , 7 ) Jupiter masses , an inclination i \ga 20 ^ { \circ } is required and the line of nodes of the system ’ s symmetry plane on the sky must lie within 0 ^ { \circ } to 50 ^ { \circ } from north eastward .
For higher masses ( M _ { b } ,M _ { c } ,M _ { d } ) from ( 7 , 10 , 10 ) to ( 11 , 13 , 13 ) , the constraints on both angles are even more stringent .
Stable orbits imply a double ( 4:2:1 ) mean-motion resonance between all three companions .
We finally show that in the cases where the companions themselves are orbitally stable , the dust-producing planetesimal belts are also stable against planetary perturbations .