A unusual comet in our solar system was observed by astronomers using the
James Webb Space Telescope, leading to a long-awaited scientific discovery
and a discovery of a new enigma.
For the first time, water was found in a comet in the main asteroid belt,
which is the region between Mars and Jupiter's orbits. After 15 years of
attempts by astronomers using various observing techniques, the finding was
made.
The discovery of water vapor by the satellite observatory near Comet Read
shows that water ice can survive in a warmer region of the solar system. The
journal
Nature
on Monday released a research outlining the conclusions.
The Kuiper Belt and the Oort Cloud, icy areas beyond Neptune's orbit that
can preserve some of the frozen components left over from the solar system's
origin, are where comets normally form. The comets have flowing tails that
form as the icy objects periodically pass near to the sun and travel on
lengthy, oval-shaped orbits around the sun that may last thousands of years.
Comets and asteroids can be distinguished by their material-filled tails and
fuzzy appearance.
Main belt comets, however, are a rare subtype of comets that are asteroids
in the asteroid belt with circular orbits around the sun that occasionally
display cometlike behavior, such as losing material to produce a fuzzy look
and a following tail.
The main belt comets appeared to release just dust, not ice through
sublimation, the direct transformation of a solid to a gas. Main belt comets
weren't thought to preserve much ice due to their placement in the warm
inner solar system farther from the sun than usual comets, but this has
changed. Additionally, the discovery could provide more proof for the
hypothesis regarding how water came to be a plentiful resource on Earth
early in its history.
The early Earth may have collided with comets and asteroids rich in water,
bringing water with it.
"Our water-soaked world, teeming with life and unique in the universe as
far as we know, is something of a mystery — we're not sure how all this
water got here," said study coauthor Stefanie Milam, Webb deputy project
scientist for planetary science at NASA's Goddard Space Flight Center in
Greenbelt, Maryland. We can better comprehend other planetary systems and
determine if they may eventually include an Earth-like planet by
understanding the history of water distribution in the solar system.
Henry Hsieh, a senior scientist at the Planetary Science Institute in
Tucson, Arizona, who is a research coauthor, and others made the initial
codiscovery of main belt comets in 2006. One of the earliest comets used to
establish the subcategory was Comet Read.
Astronomers were able to identify the trace of water vapor orbiting Comet
Read shortly after its near approach to the sun because to the exact data
gathered by Webb's Near-Infrared Spectrograph.
"In the past, we've seen objects in the main belt with all the
characteristics of comets, but only with this precise spectral data from
Webb can we say yes, it's definitely water ice that is creating that
effect," said Michael Kelley, the study's lead author and astronomer and
principal research scientist at the University of Maryland in College Park.
We can now show that water ice from the early solar system may be retained
in the asteroid belt thanks to Webb's studies of Comet Read.
With the revelation came a brand-new conundrum. Carbon dioxide, which
accounts for around 10% of the substance evaporated by the sun in all other
comets, is not present in Comet Read.
The researchers speculated that Comet Read may eventually lose its carbon
dioxide due to the greater temperatures of the main asteroid belt.
Carbon dioxide vaporizes more readily than water ice and might percolate
out over billions of years, according to Kelley. "Being in the asteroid belt
for a long time could do it," Kelley said.
Without carbon dioxide, Comet Read may potentially have developed in a
warmer region of the solar system, according to Kelley.
To find out if other main belt comets similarly lack carbon dioxide and to
decide the next steps for discovering the mysteries of uncommon comets, the
observing team is anxious to examine additional main belt comets and compare
them with Webb's findings from Comet Read.
It would be exciting to follow up on this discovery with a sample
collection mission and find out what else the main belt comets can teach us,
Milam added, "now that Webb has confirmed there is water preserved as close
as the asteroid belt."
