Comets spew greenhouse gases into space

Comets spew greenhouse gases into space

The NASA Infrared Space Telescope monitors dozens of comets, in particular, the gases they release.

The Wide-Field Infrared Survey Explorer or WISE (Wide Infrared Survey Explorer) telescope detected a multitude of comets that sweep through the Solar System, tracking the amount of carbon dioxide (CO2) and carbon monoxide (CO) ejected into space by greenhouse effects, which, as a rule It is difficult to detect using ground-based observatories.

The Neowise mission, which has become a WISE receiver, is not only able to search for weak infrared signals from distant galaxies and other mysterious phenomena, but also is able to detect infrared objects in our Solar System. After the cryogenic fuel used to keep the tools cold was exhausted in 2013, NASA scientists reloaded the ship to look for objects approaching the Earth: asteroids or comets that could pose a threat to the Earth.

But the WISE / Neowise spacecraft can do much more than just be an early warning system; it collects valuable scientific data from tracked asteroids and comets.

In a study published in the Astrophysical Journal, astronomers Neowise discovered that the process of sublimation of water ice on a comet, which occurs as it approaches the Sun, may be inferior to another process — the process of sublimation of CO and CO2 molecules that occurs in more distant and cold orbits. CO and CO2 were the main molecules in the formation of our solar system, and this primordial ice is frozen in a cometary material and can be studied as the comets pass through the inner solar system. Both CO and CO2 are abundant in the Earth’s atmosphere. CO2 is a powerful greenhouse gas, while CO has strong secondary effects on the formation of greenhouse gases, therefore, the detection of these molecules outside the Earth is problematic. But space observatories are excellent for studying these gases in the process of sublimation from comets.

"For the first time, we collected so much static carbon monoxide data that is vaporized as gas from a comet," said James Bower, deputy chief investigator for the Neowise mission at NASA's Passenger Jet Laboratory in Pasadena, California. "We discovered carbon monoxide at a distance of four astronomical units (4x distance from Earth to the Sun). The study shows that most of the gases that were used in the formation of the solar system were fixed on comets for billions of years. Most of the comets that we observe , have large orbital periods, over 200 years, and spend most of their time outside the orbit of Neptune. "

As the amount of carbon dioxide emitted, carbon monoxide and dust particles increases, a high proportion of volatile gases such as water still remain the main driving forces. But after removal from the Sun, these volatile gases remain inert (in a frozen state), while CO and CO2 become the main driving forces of sublimation. This Neowise study may complement the findings of the European Rosette Mission, which is currently in orbit of comet 67P / Churyumov-Gerasimenko. Rosette was launched into 67P orbit since 2014 and recently experienced perihelion (the point of closest approach to the Sun), tracking the concentration of chemicals.

Rosette found not only an increase in the concentration of CO2 and water vapor in coma 67P (in the atmosphere of a comet around the solid core), she also spotted a mixture of ammonia, methane, hydrogen cyanide and formaldehyde. All these substances have been locked in the ices of the comet since its formation.

Thus, astronomical research on Neowise and the Rosette mission not only help to understand the nature of comets, they also carry out “archaeological excavations” of the period of the formation of our Solar System.

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