NCCR PlanetS: Capturing Alien Comets
Posted: Fri Dec 20, 2019 7:33 pm
Capturing Alien Comets
National Centre of Competence in Research PlanetS | 2019 Dec 19
Capture of Interstellar Objects: A Source of Long-Period Comets ~ Tom Hands, Walter Dehnen
National Centre of Competence in Research PlanetS | 2019 Dec 19
There should be interstellar comets hiding in our Solar system after making a journey of many lightyears. Maybe we have already seen one but believed it was a “normal” comet formed in the Solar system. ...
Comets that suddenly light up in the sky, only to disappear again after some weeks or months, have fascinated humanity for centuries. Where do these exotic objects come from? According to the most popular theory proposed by Dutch astronomer Jan Oort, during a very early phase of the Solar system’s formation the giant planets scattered objects into the outer regions far away from the Sun. There, the icy rocks and dust particles formed a kind of cloud. Passing stars may then scatter these objects back into the inner Solar system where we observe them as comets. Coming from the Oort cloud these long-period comets often need many more than 200 years for one orbit around the Sun.
“We present a second potential origin for such comets,” says Tom Hands, postdoc at the Institute for Computational Science of the University of Zürich: “They can be captured out of interstellar space in the relatively recent past.” Two interstellar visitors made headlines in the past years. In 2017, the first such object was detected, an asteroid-like body later named Oumuamua. In August 2019 amateur astronomer Gennady Borisov found a comet that came from interstellar space and will leave the Solar system again. Oumuamua and Comet Borisov are both leftovers of planet formation in other Solar systems, in the same way our comets and asteroids are thought to be the leftovers of planet formation in our Solar system. ...
Capture of Interstellar Objects: A Source of Long-Period Comets ~ Tom Hands, Walter Dehnen
- Monthly Notices of the RAS: Letters (online 18 Dec 2019) DOI: 10.1093/mnrasl/slz186
- arXiv.org > astro-ph > arXiv:1910.06338 > 14 Oct 2019