At http://phys.org/print381157131.html … a paper due out in May's Science Advances (2016) is set to claim C/2014 S3 PANSTARRS is an ancient rocky body – much like an asteroid. Comets are supposed to be icy conglomerates so is this really a comet or is it an asteroid behaving like a comet?
It was first identified back in 2014 when it was a weakly active comet. It is said to have a very long orbit of 860 years. The claim is that it was recently nudged out of the Oort Cloud (a theoretical cloud of comets and asteroids out there somewhere). This comet is said to be tail less (like a Manx cat) but why this should be so is not elaborated on. We shall know more when the paper is published. The authors are making a bold claim. They say they have found the 'first' rocky comet – but is this true? What is useful is that they, and others, will be out there looking for further examples of rocky bodies posing as comets.