Humans are now a little better equipped to unlock the secrets of the next space rock
that passes through our solar system from beyond.
So far, astronomers have spotted two interstellar objects that raced through the solar system
from other neighbors.
There was ‘Oumuamua in 2017 and Borisov in 2018, but many more are believed to exist.
However, because these objects appear unpredictable, scientists must rush to collect as many observations
as possible during the short period they are close enough to investigate.
Luckily, NASA’s James Webb Space Telescope, which was recently launched, should help to
broaden that window.
Webb brings a fresh set of skills to the table.
Martin Cordiner, the principal investigator of the project, stated that because of Webb’s
extreme sensitivity and power, scientists now have a once-in-a-lifetime opportunity
to investigate the chemical composition of these interstellar objects.
They will also learn a great deal more about their origins, how they were formed, and what
they can tell us about the conditions in their home systems.
It’s a very incredible thing to be able to investigate an interstellar object and
determine its composition.
The first two interstellar objects spotted were quite different: One resembled a comet,
while the other did not.
Scientists hope that soon they’ll get to know how unique those objects were and if
they’re reflective of the interstellar population as a whole.
Currently, astronomers are continually analyzing a variety of sources of data, from amateur
observers to professional observatories, in the hopes of discovering the next interstellar
invader.
When scientists detect such an object, they won’t know for sure if it’s an interstellar
object right away.
Depending on its brightness, they’ll require more observations for days, weeks, or perhaps
months to confirm it.
After they’ve confirmed that the object came from beyond the solar system based on
its “hyperbolic” orbit, and that it didn’t come from the far limits of our solar system
or the Oort cloud, they can compute the object’s path across the sky.
Scientists will observe if that path crosses with Webb’s field of view.
The team will explore two different aspects of the interstellar object using Webb’s
spectroscopic powers in the near-infrared and mid-infrared regions.
First, they’ll use the Near-Infrared Spectrograph (NIRSpec) to examine the chemical fingerprints
of gases produced by the object as any ices present are evaporated by the Sun’s radiation.
Second, they’ll use the Mid-Infrared Instrument (MIRI) to see if the object produces any dust.
Thanks to its high spectral resolution, NIRSpec can pick out the emission from individual
gases, thus allowing the scientists to detect specific molecules such as water, methane,
carbon dioxide, carbon monoxide, and methanol.
MIRI, which is in the midinfrared, is more sensitive to the heat spectrum produced by
solid particles like dust grains or the object’s nucleus.
Webb has the potential to disclose comparable significant insights into the chemistry of
planet formation around other stars.
Scientists cannot fully comprehend the exact chemical processes involved in planet formation.
For instance, how can a planet form from simple chemical elements?
Is the process the same for all stars?
Was there anything unusual about how our planets formed around the Sun compared to how they
formed around other stars in the galaxy?
Suppose astronomers can obtain proof of the chemical conditions existent in other planetary
systems by viewing an interstellar object and determining what it is made of.
In that case, that means they can have a much better understanding of the full degree of
chemistry that is possible in those other planetary systems.
Since interstellar objects have never been seen in these critical near-and mid-infrared
wavelength regions, the potential for new discoveries is a great deal.
Gathering and examining infrared light is a unique strength of the James Webb Space
Telescope.
The telescope must be placed so far from Earth and have a sophisticated sun shield because
heat interferes with infrared detections.
However, scientists believe that infrared detections will be worth the effort, even
for interstellar objects.
They have no idea what they will uncover among the trillions of interstellar objects swarming
around the galaxy, but they know it will be exciting.
NASA expects the telescope to be capturing images by June, and astronomers can’t wait
for this.