APOD: The Seventh World of Trappist-1 (2023 Feb 01)

Comments and questions about the APOD on the main view screen.
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APOD Robot
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APOD: The Seventh World of Trappist-1 (2023 Feb 01)

Post by APOD Robot » Wed Feb 01, 2023 5:05 am

Image The Seventh World of Trappist-1

Explanation: Seven worlds orbit the ultracool dwarf star TRAPPIST-1. A mere 40 light-years away, many of the exoplanets were discovered in 2016 using the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) located in the Atlas Mountains of Morocco, and later confirmed with telescope including NASA's Spitzer Space Telescope. The TRAPPIST-1 planets are likely all rocky and similar in size to Earth, and so compose one of the largest treasure troves of terrestrial planets ever detected around a single star. Because they orbit very close to their faint, tiny star they could also have regions where surface temperatures allow for the presence of ice or even liquid water, a key ingredient for life. Their tantalizing proximity to Earth makes them prime candidates for future telescopic explorations of the atmospheres of potentially habitable planets. All seven exoplanets appear in the featured illustration, which imagines a view from the most distant known world of this system, TRAPPIST-1h, as having a rocky landscape covered in ice. Meanwhile, in the imagined background, one of the system's inner planets crosses in front of the dim, orange, nearly Jupiter-sized parent star.

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Holger Nielsen
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Re: APOD: The Seventh World of Trappist-1 (2023 Feb 01)

Post by Holger Nielsen » Wed Feb 01, 2023 9:17 am

When seeing illustrations of this kind, I am always a little suspicious: Are the discs shown really that large? So I did a little calculation using data (in green) from the Internet:
TRAPPIST system.jpg
The central star has an angular diameter of about 1°, twice the value of that of the Sun as seen from Earth. Perhaps the illustration exaggerates somewhat here. On the other hand, the diameter of the closest planet, g, is about 1/3 that of the star, which is in agreement with the illustration. The angular diameter of planet f is 13 arc minutes, so it seems reasonable to show it with a sickle. The artist probably did the same calculation in preparation!
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johnnydeep
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Re: APOD: The Seventh World of Trappist-1 (2023 Feb 01)

Post by johnnydeep » Wed Feb 01, 2023 4:45 pm

Oh man, what I wouldn't give to be able to get a fleet of probes sent there, and to be able to see the images they return! Yes, I know the system is 40 ly away and thus entirely inaccessible to local probes in my lifetime (or indeed many lifetimes), but this nearby trove of potentially habitable planets in our virtual backyard sure does get my imaginative juices flowing!
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AVAO
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Re: APOD: The Seventh World of Trappist-1 (2023 Feb 01)

Post by AVAO » Wed Feb 01, 2023 8:08 pm

Holger Nielsen wrote: Wed Feb 01, 2023 9:17 am When seeing illustrations of this kind, I am always a little suspicious: Are the discs shown really that large? So I did a little calculation using data (in green) from the Internet:

TRAPPIST system.jpg

The central star has an angular diameter of about 1°, twice the value of that of the Sun as seen from Earth. Perhaps the illustration exaggerates somewhat here. On the other hand, the diameter of the closest planet, g, is about 1/3 that of the star, which is in agreement with the illustration. The angular diameter of planet f is 13 arc minutes, so it seems reasonable to show it with a sickle. The artist probably did the same calculation in preparation!
I can only confirm your assumptions. My spatial simulation shows that the conditions are actually realistic. Only the statement "..., one of the system's inner planets crosses in front of the dim, orange, nearly Jupiter-sized parent star. " can still be put into perspective, since it must be the second outermost planet that covers the disc of the central star. All others would be much smaller in proportion.

Perspective view from the last star:
Image

Image
https://www.eso.org/public/images/eso1805i/?lang

I also like these videos. The first link is an interactive 3D video animation which drives me crazy:

https://www.youtube.com/watch?v=OOwI3nTAHIc&t=1s

https://www.youtube.com/watch?v=YMLus46vGHM
https://www.youtube.com/watch?v=2LEUe2_8pJg&t=20s

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orin stepanek
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Re: APOD: The Seventh World of Trappist-1 (2023 Feb 01)

Post by orin stepanek » Thu Feb 02, 2023 1:58 am

Trappist1h_Carroll_960.jpg
:evil: Looks to me like one of the Stone heads of Easter Island got
snow blasted and sent there! :mrgreen:
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RJN
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Re: APOD: The Seventh World of Trappist-1 (2023 Feb 01)

Post by RJN » Tue Feb 07, 2023 9:38 pm

An emailer has alerted APOD that this system was discovered using the southern TRAPPIST obsevatory at La Silla Observatory in Chile, not the northern version of TRAPPIST in Morocco as originally claimed. This has now been corrected on the main NASA site at apod.nasa.gov. We apologize for the oversight. - RJN