The second coming of sungrazing comets

There’s only one comet likely to be magnitude 10 or brighter during the closing months of winter, and that will once again be the distant C/2017 K2 (PANSTARRS). This slow-moving object will begin July in Ophiuchus and drift into Scorpius during the first week of August, staying within the bounds of that constellation for the rest of the month (except for a very brief incursion into Libra on August 23–24).

C/2017 K2 will make its closest approach to Earth (1.8