(unrelated to my other post about an asteroid) 1] I would like to check a postulation with someone who has an orbital simulator, or a good head for orbital mechanics. Given an object such as a comet with orbital period of about 150 years, could it have a perihelion at a distance between Mercury and Venus? If no, what does work? Change period? Change perihelion? 2] Could we tell anything about this object's mass from its orbit and/or visual observations if we do not know its density or its albedo factor?