The question is a bit unrealistic with its circumstances but lets assume there is a bucket of ice cooled down to about absolute zero and is about 1000 km away (all around the sun) from sun and moving with v_0 = 100km/sec, what will be if that all water with mass of sun reaches the sun.

UPDATE

Basically I have read about this in gizmodo http://gizmodo.com/could-the-sun-be-extinguished-by-a-bucket-of-water-just-1669914928 but did not agreed , thats why I have decided to ask about this phenomena here, hoping to find out more precise answer