On Sat, 2 Dec 2017 22:56:31 -0800 (PST), Quadibloc wrote:

The perihelion of 'Oomuamua is 0.25534 AU, which is indeed within the orbit of
Mercury (semi-major axis, 0.387 AU). However, the perihelion of Icarus is 0.1867
AU, so there are objects in our Solar System that pass closer to the Sun

Thank you, I was not aware of any objects with a smaller perihelion than
Mercury.

My point re-phrased should thus have had something to do with an estimate
of the fraction of the known objects in the Solar System that have
perihelion less than 'Oomuamua.

I do understand that, for a given 'hyperbolic excess velocity', a smaller
course-change angle will be seen in objects with greater perihelion, and
thus are less likely to be observed. (Because they are further away from
our 'scopes).

I suppose it's 'suspicious' closeness to the sun really needs to be
compared to perihelia of other extra-System objects (i.e. the 'several'
estimated per year even though we have never seen any of them.) Otherwise,
I am generalizing on one unique event.

And as others have pointed out, what is REALLY suspicious is its shape. I
suppose we need to compare the shapes of all those 'several' other such
objects.