All Comets in Our Solar System May Have Come From the Same Place

This single frame Rosetta navigation camera image of Comet 67P/Churyumov-Gerasimenko was taken on July 7, 2015 from a distance of 154 km from the comet center. (Image: ESA/Rosetta/NAVCAM )
This single frame Rosetta navigation camera image of Comet 67P/Churyumov-Gerasimenko was taken on July 7, 2015 from a distance of 154 km from the comet center. (Image: ESA/Rosetta/NAVCAM )

All comets might share their place of birth, new research says. For the first time ever, astronomer Christian Eistrup applied chemical models to 14 well-known comets, surprisingly finding a clear pattern. His publication has been accepted in the journal Astronomy & Astrophysics.

Comets: balls of ice or more?

Comets travel through our solar system and are composed of ice, dust, and small rock-like particles. Their nuclei can be as large as tens of kilometers across. Eistrup said:

Comets travel through our solar system and are composed of ice, dust, and small rock-like particles. (Image: NASA)

Comets travel through our solar system and are composed of ice, dust, and small rock-like particles. (Image: NASA)

A new take on comets

“What if I apply our existing chemical models to comets?” Eistrup thought during his Ph.D. at Leiden University. In the research team at Leiden Observatory, which included Kavli Prize winner Ewine van Dishoeck, he developed models to predict the chemical composition of protoplanetary discs — flat discs of gas and dust encompassing young stars.

Understanding these discs can give insight into how stars and planets form. Conveniently, these Leiden models turned out to be of help in learning about comets and their origins. Eistrup said:

This happened to be the case and to a surprising extent. Where the researchers hoped for a number of comets sharing similarities, it turned out that all 14 comets showed the same trend. “There was a single model that fitted each comet best, thereby indicating that they share their origin.”

Ice-cold

And that origin is somewhere close to our young Sun, when it was still encircled by a protoplanetary disc and our planets were still forming. The model suggests a zone around the Sun, inside the range where carbon monoxide becomes ice — relatively far away from the nucleus of the young Sun.

But if comets come from the same place, how do they end up in different places and orbits in our solar system?

Comets are everywhere, and sometimes with very funky orbits around the Sun. (Image: wikimedia / CC0 1.0)

Comets are everywhere, and sometimes with very funky orbits around the Sun. (Image: wikimedia / CC0 1.0)

Comet data hunter

As befits a scientist, Eistrup places some side-notes to his publication.

Eistrup also hopes that astronomers that study the origin of our solar system and its evolution can use his results.

He is also keen to get in touch with other comet researchers.

The seeds of life

Comets and life on Earth, they go hand in hand. Eistrup concluded:

So, interestingly, understanding the birth of comets potentially could help us understand the birth of life on Earth.

Provided by: Bryce Benda, Leiden University [Note: Materials may be edited for content and length.]

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