Astronomers discover comet covered with ‘talcum powder’


Astronomers at Kyoto Sangyo University in Japan made a curious discovery by observing a comet that is in the final stage of its life: it is covered by a substance similar to talcum powder. The novelty was revealed in a study published in the journal Icarus in March.

First sighted in January 2016, comet P / 2016 BA14 (Panstarrs) soon aroused the curiosity of scientists, due to its different activity. The strange behavior confused observers, who even thought it was an asteroid.

Later, it was discovered that it was actually a comet, but in a weakened state, after some approximations of the Sun. In this process, which normally results in the formation of impressive tails, the celestial body was heated, losing gas and dust.

And it was during these journeys that the object became worn out, reaching its current state. “It is believed that after many trips through the inner Solar System, this comet has burned almost all of its ice and is now approaching the end of its cometary life,” suggested the team responsible for the study.

Where does “talcum powder” come from?

Using the Subaru telescope of the National Astronomical Observatory of Japan (NAOJ), aimed at the comet for 30 hours, astronomers were able to observe it more closely when it passed 3.6 million km away from Earth, the equivalent of nine times the distance between the Moon and our planet, on March 22, 2016.

The observation of the curious celestial star made five years ago, using thermal infrared radiation, the same technology found in non-contact thermometers that have become quite common in our daily lives, allowed not only to measure its temperature, but also to study the composition of its surface , showing some interesting details.

Astronomers have discovered that P / 2016 BA14 (Panstarrs) is 800 meters in diameter and that its surface is covered by organic molecules and huge grains of phyllosilicate. On Earth, this substance is found in the popular talcum powder, used on several occasions.

According to the research, this is the first time that hydrated silicate minerals, such as talc, are found on a comet. By comparing the substances found in it with measurements made in the laboratory, the scientists concluded that the grains in the celestial body have been heated to more than 300 ºC in the past, suggesting their presence in an orbit closer to the Sun – currently, the temperature on its surface it is “only” 130 ºC.

Future visit

The surprising discovery made by Japanese astronomers raised another question: was the talcum powder on the surface of the comet always there, part of the natural formation of the object, or did it arise after it had approached the Sun countless times?

For astronomer Takafumi Ootsubo, the answer may provide a valuable clue to studying the development of these objects. “We believe that other observations from the nuclei of the comet will allow us to learn more about this evolution”, commented the main author of the study.

Despite being in its final stage of life, as the characteristics described in the research point out, comet P / 2016 BA14 (Panstarrs) became a potential candidate to receive a visit from the Comet Interceptor mission soon. It is organized by the European Space Agency (ESA), in partnership with the Japanese Aerospace Exploration Agency (JAXA).

Composed of three spaceships, the mission can visit a comet approaching Earth and make simultaneous observations from various points around it, generating a 3D image of the object.


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