Cosmic Rays Erode Away All But the Largest Interstellar Objects

So far we know of only two interstellar objects (ISO) to visit our Solar System. They are ‘Oumuamua and 2I/Borisov. There’s a third possible ISO named CNEOS 2014-01-08, and research suggests there should be many more.

But a new research letter shows that cosmic ray erosion limits the lifespan of icy ISOs, and though there may be many more of them, they simply don’t last as long as thought. If it’s true, then ‘Oumuamua was probably substantially larger when it started its journey, wherever that was.

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Protoplanetary Disks Throw Out More Material Than Gets Turned Into Planets

When a young solar system gets going it’s little more than a young star and a rotating disk of debris. Accepted thinking says that the swirling debris is swept up in planet formation. But a new study says that much of the matter in the disk could face a different fate.

It may not have the honour of becoming part of a nice stable planet, orbiting placidly and reliably around its host star. Instead, it’s simply discarded. It’s ejected out of the young, still-forming solar system to spend its existence as interstellar objects or as rogue planets.

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Interstellar Objects Might Outnumber Solar System Objects in the Oort Cloud

Our solar system is filled with everything from planets to rocky asteroids to small icy bodies beyond Pluto, but surrounding all of it is a diffuse halo of objects known as the Oort cloud. We haven’t directly observed the Oort cloud, but we’re pretty sure it’s there by observing the distribution of comet in our solar system. They can appear from any direction in the sky rather than just along the common plane of known solar system bodies.

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When Stars Get Too Close to Each Other, They Cast Out Interstellar Comets and Asteroids

In October 2017, humanity caught its first-ever glimpse of an interstellar object – a visitor from beyond our solar system – passing nearby the Sun. We named it Oumuamua, and its unusual properties fascinated and confounded astronomers. Less than two years later, amateur astronomer Gennady Borisov found a second interstellar object: a comet-like body that began to disintegrate as it passed within 2 AU of the Sun (1 AU equals the distance from Earth to the Sun). Where do these interstellar objects come from? How common are they? With a sample size of just two, it’s difficult to make any generalizations just yet. On the other hand, given what we know about star formation, we can begin to make some inferences about the likely origins of these objects, and what we are likely to see of them in the future.

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There Should be About 7 Interstellar Objects Passing Through the Inner Solar System Every Year

In October 19th, 2017, the first interstellar object ever detected flew past Earth on its way out of the Solar System. Less than two years later, a second object was detected, an easily-identified interstellar comet designated as 2I/Borisov. The appearance of these two objects verified earlier theoretical work that concluded that interstellar objects (ISOs) regularly enter our Solar System.

The question of how often this happens has been the subject of considerable research since then. According to a new study led by researchers from the Initiative for Interstellar Studies (i4is), roughly 7 ISOs enter our Solar System every year and follow predictable orbits while they are here. This research could allow us to send a spacecraft to rendezvous with one of these objects in the near future.

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Vera Rubin Should be Able to Detect a Couple of Interstellar Objects a Month

The Vera C. Rubin Observatory, formerly the Large Synoptic Survey Telescope (LSST), will commence operations sometime next year. Not wanting to let a perfectly good acronym go to waste, its first campaign will be known as the Legacy Survey of Space and Time (LSST). This ten-year survey will study everything from dark matter and dark energy to the formation of the Milky Way, and small objects in our Solar System.

According to a new study by Amir Siraj and Prof. Abraham Loeb of Harvard University, another benefit of this survey will be the discovery of interstellar objects that regularly enter the Solar Systems. These results, when combined with physical characterizations of the objects, will teach us a great deal about the origin and nature of planetary systems (and could even help us spot an alien probe or two!)

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We Have the Technology to Retrieve a Sample From an Interstellar Object Like Oumuamua

On October 19th, 2017, astronomers were astounded to learn that an interstellar object (named ‘Oumuamua) flew by Earth on its way out of the Solar System. Years later, astronomers are still debating what this object was – a comet fragment, a hydrogen iceberg, or an extraterrestrial solar sail? What’s more, the arrival of 2I/Borisov two years later showed how interstellar objects (ISOs) regularly enter our Solar System (some even stay!)

It’s little wonder then why proposals are in place to design missions that could rendezvous with an interstellar object the next time one passes by. One such mission is Project Lyra, a concept proposed by researchers from the Initiative for Interstellar Studies (i4is). Recently, an international team led from the I4IS drafted a White Paper that was submitted to the 2023-2032 Planetary Science and Astrobiology Decadal Survey.

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Interstellar Comet 2I/Borisov Formed in a Very Cold Environment

In the summer of 2019, a team of astronomers from NASA, the ESA, and the International Scientific Optical Network (ISON) announced the detection of the comet 2I/Borisov. This comet was the only second interstellar visitor observed passed through our Solar System, coming on the heels of the mysterious ‘Oumuamua. For this reason, astronomers from all over the world watched this comet intently as it made its closest pass to the Sun.

One such group, led by Martin Cordiner and Stefanie Milam of NASA’s Goddard Space Flight Center, observed 2I/Borisov using the ESO’s Atacama Large Millimeter/submillimeter Array (ALMA) in the Chilean Andes. This allowed them to observe the gases 2I/Borisov released as it moved closer to our Sun, thus providing the first-ever chemical composition readings of an interstellar object.

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