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We finally get to spot a burnt-out comet and what is it covered in? Talcum powder

(2021/04/07)


Not only did a telescope on Earth spot, for the first time in history, an extinct comet on a close fly-by of our home world but scientists now reckon the space rock is covered in a substance similar to talcum powder.

Night-sky watchers from the National Astronomical Observatory of Japan (NAOJ) and the Koyama Astronomical Observatory discovered Comet P/2016 BA 14 five years ago, and recorded it for 30 hours as it made its closest approach to Earth. They initially thought the rock was an asteroid, though the data showed it was an unusual comet.

[1]

Unlike most comets, P/2016 BA 14 was not shrouded in a halo of dust and ice. In fact, it is coated in large phyllosilicate grains, a substance more commonly used on Earth for talcum powder.

“This result provides us a precious clue to study the evolution of comets,” [2]said Takafumi Ootsubo, the lead author of a study into the body and an astronomer at NAOJ, on Tuesday. “We believe that further observations of the comet nuclei will enable us to learn more about the evolution of comets.”

[3]

When comets are warmed by sunlight, they are typically wrapped in an envelope of gases that give it a fuzzy appearance. The gases are produced when the ice and dust on its surface sublimate, and as these objects streak across the sky sometimes the particles are compressed into a tail.

And now for something completely different: Ultraviolet aurora spotted around comet for first time [4]READ MORE

Comet P/2016 BA 14 , however, emits very little of these gases or particles because the material on its surface has mostly disappeared. Observations made using the Subaru Telescope reveals that underneath what remains of the ice and dust is a generous coating of something close to talcum powder.

“The normalized emissivity spectrum of the comet exhibits absorption-like features that are not reproduced by the anhydrous minerals typically found in cometary dust coma, such as olivine and pyroxene,” the study, [5]published in the journal Icarus, reads.

“Instead, the spectral features suggest the presence of large grains of phyllosilicate minerals and organic materials. Thus, our observations indicate that an inactive small body covered with these processed materials is a possible end state of comets.”

It’s the first time scientists have found hydrous silicate materials in or on a comet. The team estimated that the 800-metre-wide specimen has been scorched to temperatures beyond 330°C, and was probably in an orbit that brought it closer to the Sun than its current path.

[6]

The observations were made on March 22, 2016 when the comet passed within 3.6 million kilometres of our home planet. The team wants to figure out if the comet accrued the powder on its body or if the phyllosilicate was there from the start. Detecting more near-dead comets could help confirm whether these objects do, indeed, transform into dead husks of talcum powder after one too many trips around the Sun. ®

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[1] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YG2Cx8THAt-QvvGBo33y@gAAAMY&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

[2] https://www.nao.ac.jp/en/news/science/2021/20210406-subaru.html

[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33YG2Cx8THAt-QvvGBo33y@gAAAMY&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[4] https://www.theregister.com/2020/09/23/ultraviolet_aurora_comet_67p/

[5] https://www.sciencedirect.com/science/article/abs/pii/S0019103521001093

[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YG2Cx8THAt-QvvGBo33y@gAAAMY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[7] https://whitepapers.theregister.com/

That will teach the comets

Andy Non

to use sun lotion. Much better than applying talcum powder after you've been sizzled to a crisp by the sun.

Re: That will teach the comets

TRT

I wonder if there’s talc around Uranus?

Re: That will teach the comets

Andy Non

Nobody is brave enough to find out.

Failed though?

Mike 137

Even with all that talcum, all comets still have shiny noses.

Maybe

Chris G

It's not an old comet but a youngster that has been recently bathed and talced?

Ding dong!

DJV

...or it's an interstellar Avon lady plying her (rather limited selection of) wares.

interesting

Denarius

seems consistent with Deep Impact results. Huge cloud of clays which was not expected.

It was 3.5 million kilometers away

Pascal Monett

And an Earth-based telescope allowed boffins to determine that it has talcum powder on the surface. The image quality, power and precision to establish that is simply staggering. Well done.

No so well done for the [1]wiki page though, it doesn't mention the Subaru telescope at all.

[1] https://en.wikipedia.org/wiki/P/2016_BA14

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