Although it has been more than a decade since Comet Hale-Bopp blazed in the night sky, it’s still sputtering as it continues to head into cold, trans-Neptunian space.
In a paper submitted to the Astrophysical Journal Letters, a trio of Hungarian and Australian astronomers describe capturing the most distant cometary activity ever seen.
The team imaged Hale-Bopp over three nights last October, when the comet was nearly 26 astronomical units (2.4 billion miles) from the Sun. At 20th magnitude, it wasn’t much to look at, just a smudge about a dozen pixels across as captured using the 2.3-meter Australian National University telescope at the Siding Spring Observatory. But the images were enough for the researchers to conclude that the nucleus is still releasing carbon monoxide gas into a coma more than 100,000 miles wide.