My sister is a devout and consistent believer in the reemergence of "the Christ" and says according to her group that a star is now going to be visible to all nations as a herald of the re-emergence of "Maitreya" the World Teacher. This seems simply outlandish to us. I invite all astronomy scientists to respond. Are there any recent new "stars" out there just now popping up?

Yes, new stars form constantly in molecular clouds, the closest of which is the orion nebula. This of course is a purely natural process, and not linked to any religious poppycockery.

Are there any recent new "stars" out there just now popping up?

No - at least nothing visible to the naked eye. Capuchin notes that new stars are being formed all the time, but none that we have observed suddenly bursting forth in the past few weeks, or months, or even years. In addition, when old stars reach end of life it is not uncommon for them to suddenly brighten, perhaps in a nova or super nova explosion, which to us on earth may appear as the temporary appearance of a "new star" when in fact we are actually witnesing the death of an old star. Astronomers typically observe several such novae each year, with the great majority being observed in other galaxies, and hence not visible to the naked eye. There is no evidence right now of any such nova occurring in our own galactic neighborhood that would be obsevable without a sophisticated telescope. But it's always possible - one could happen tomorrow.