So I'm writing a sci-fi story. The overarching details are not of particular importance to this query.
One of the principle macguffins the Heroes must deal with is an asteroid heading for Earth.
Designation: Far Kuiper Belt object
Diameter: ~30km (massive enough to cause an ELE)
Orbital Period: ~4900 years (plot point)
Perihelion: 1 AU (Earth orbit)
Orbital Inclination: 80 degrees
Next Perihelion: ~13 years from 'present'
Is is remotely plausible that such an object has remained undetected by present-day (~2000) astronomers?
Our heroes have 13 years and change to deflect it. The plan is to attach a VASIMR-like drive to the asteroid and nudge its orbit so that it no longer impacts Earth.
I am trying my best to stick to scientifically-grounded principles in the story. (I am a sysadmin scifi geek, not an astronomer) the physics have to be real enough to not catch the wrath of many a Bad Astronomer.
Will the above 'work' without stretching credibility?