Archival Images Reveal Comet 28P/Neujmin Blurs Line Between Asteroids and Comets

In the vast archive of a Hawaiian mountaintop telescope, Japanese astronomers found an accidental portrait of a comet stripped of its usual veil — and in that rare nakedness, discovered that the ancient boundary between comets and asteroids may be less a wall than a gradual fading. Comet 28P/Neujmin, a 21-kilometer wanderer orbiting the Sun every 18 years, reflects light like a D-type asteroid yet carries a looser, fluffier interior structure that belongs to neither category cleanly. The finding, drawn from archival Subaru Telescope images, suggests that comets and asteroids may be siblings sh