APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Comments and questions about the APOD on the main view screen.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby neufer » Sun Feb 26, 2017 8:25 pm

geckzilla wrote:
1. Almost, but not quite. The dope sheet might interest you. Each diamond is a return to original position / 1 revolution. 100 frames = 1 day so 3615 is where the system stands after 36.15 days.

    What about 36.15 days?
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby geckzilla » Sun Feb 26, 2017 8:42 pm

Same, even with numbers fail fixed. (Guess it's bedtime.) You can see it in the dope sheet. They don't line up again.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby neufer » Sun Feb 26, 2017 10:25 pm

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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby alter-ego » Mon Feb 27, 2017 6:51 am

geckzilla wrote:Same, even with numbers fail fixed. (Guess it's bedtime.) You can see it in the dope sheet. They don't line up again.

What assumptions does Blender make?
The orbits have inclination differences and eccentricities. Also, Trappist-1 subtends an angle ranging from 5.5° to 1.4°for planets b thru g.
Regarding angular size alone, if you are not accounting for an extended stellar size, than you could easily be missing a multi-transit event (i.e. the diamonds don't exactly have to line up).
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby geckzilla » Mon Feb 27, 2017 7:09 am

alter-ego wrote:
geckzilla wrote:Same, even with numbers fail fixed. (Guess it's bedtime.) You can see it in the dope sheet. They don't line up again.

What assumptions does Blender make?
The orbits have inclination differences and eccentricities. Also, Trappist-1 subtends an angle ranging from 5.5° to 1.4°for planets b thru g.
Regarding angular size alone, if you are not accounting for an extended stellar size, than you could easily be missing a multi-transit event (i.e. the diamonds don't exactly have to line up).

No assumptions that I don't make, myself. I included inclination, but not eccentricities, partly because they are so small that they are nearly perfect circles anyway, and my circles are not circles but a series of segments. Size is accounted for. Here's a video I made earlier showing one of the planets passing by another.
Click to play embedded YouTube video.


I know they don't have to be in a perfect line, but so far it's not even close. Their orbital planes are so closely aligned that they transit one another all the time, just not necessarily while in front of the star.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby neufer » Mon Feb 27, 2017 2:23 pm

If these planets ever do line up then:

    1) every 36.15 days the planets realign

    2) every 41st realignment (i.e., 1482.15 days)
    the planets are back to their original positions:
    ---------------------------------------------
    41 x 36.15 days = 1482.15 days
    ......................................
    980.991 orbits of b (Gretl)
    611.998 orbits of c (Marta)
    365.998 orbits of d (Brigitta)
    242.991 orbits of e (Kurt)
    160.986 orbits of f (Louisa)
    119.984 orbits of g (Friedrich)

    (More or Less)
Last edited by neufer on Mon Feb 27, 2017 11:14 pm, edited 1 time in total.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby BDanielMayfield » Mon Feb 27, 2017 4:17 pm

neufer wrote:If these planets ever do line up then:

    1) every 36.15 days the planets realign

    2) every 41st realignment (i.e., 1482.15 days)
    the planets are back to their original positions:
    ---------------------------------------------
    41 x 36.15 days = 1482.15 days
    ......................................
    990.991 orbits of b (Gretl)
    611.998 orbits of c (Marta)
    365.998 orbits of d (Brigitta)
    242.991 orbits of e (Kurt)
    160.986 orbits of f (Louisa)
    119.984 orbits of g (Friedrich)

    (More or Less)


More, because you've left out h.

Syzygy, a great word to know when playing scrabble.

At least three of these TRAPPIST-1 planets have already been observed in transit at the same time. So TRAPPIST-1, three of its ducklings, and the Earth all got in a row.

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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby Chris Peterson » Mon Feb 27, 2017 4:31 pm

BDanielMayfield wrote:Syzygy, a great word to know when playing scrabble.

It could be... but you'll need a non-scoring blank tile to pull it off, since there are only two "Y" tiles in a normal English game set.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby neufer » Mon Feb 27, 2017 4:58 pm

BDanielMayfield wrote:
neufer wrote:If these planets ever do line up then:

    1) every 36.15 days the planets realign

    2) every 41st realignment (i.e., 1482.15 days)
    the planets are back to their original positions:
    ---------------------------------------------
    41 x 36.15 days = 1482.15 days
    ......................................
    980.991 orbits of b (Gretl)
    611.998 orbits of c (Marta)
    365.998 orbits of d (Brigitta)
    242.991 orbits of e (Kurt)
    160.986 orbits of f (Louisa)
    119.984 orbits of g (Friedrich)

    (More or Less)

More, because you've left out h.


With an orbital period of 20+15−6 days we're very
unsure about Liesl's whereabouts after 1482.15 days.
(Perhaps she snuck out to the gazebo with Rowlf.)

BDanielMayfield wrote:
Syzygy, a great word to know when playing scrabble. At least three of these TRAPPIST-1 planets have already been observed in transit at the same time. So TRAPPIST-1, three of its ducklings, and the Earth all got in a row.

Which three were those :?:
Last edited by neufer on Mon Feb 27, 2017 11:12 pm, edited 1 time in total.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby neufer » Mon Feb 27, 2017 5:10 pm

Chris Peterson wrote:
BDanielMayfield wrote:
Syzygy, a great word to know when playing scrabble.

It could be... but you'll need a non-scoring blank tile to pull it off, since there are only two "Y" tiles in a normal English game set.

https://en.wikipedia.org/wiki/Scrabble_ ... ions#Welsh wrote:
Welsh-language Scrabble sets use these 105 tiles:

2 blank tiles (scoring 0 points)
1 point: A ×10, E ×8, N ×8, I ×7, R ×7, Y ×7, D ×6, O ×6, W ×5, DD ×4
2 points: F ×3, G ×3, L ×3, U ×3
3 points: S ×3, B ×2, M ×2, T ×2
4 points: C ×2, FF ×2, H ×2, TH ×2
5 points: CH ×1, LL ×1, P ×1
8 points: J ×1
10 points: NG ×1, RH ×1

Since there are specific tiles for the digraphs that are considered to be separate letters in Welsh orthography (such as DD), it is not permissible to use the individual letters to spell these out. Diacritics on letters are ignored. The digraph PH also exists in Welsh, but is omitted because it is used almost exclusively in mutated words, which the rules disallow. K, Q, V, X and Z also do not exist in Welsh. J does not exist in traditional Welsh either, but it is included as it is used in some borrowed words.>>
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby Chris Peterson » Mon Feb 27, 2017 5:27 pm

neufer wrote:
Chris Peterson wrote:
BDanielMayfield wrote:
Syzygy, a great word to know when playing scrabble.

It could be... but you'll need a non-scoring blank tile to pull it off, since there are only two "Y" tiles in a normal English game set.

https://en.wikipedia.org/wiki/Scrabble_ ... ions#Welsh wrote:Since there are specific tiles for the digraphs that are considered to be separate letters in Welsh orthography (such as DD), it is not permissible to use the individual letters to spell these out. Diacritics on letters are ignored. The digraph PH also exists in Welsh, but is omitted because it is used almost exclusively in mutated words, which the rules disallow. K, Q, V, X and Z also do not exist in Welsh. J does not exist in traditional Welsh either, but it is included as it is used in some borrowed words.>>

While "Z" may not exist in traditional Welsh, it is used. In fact, the common Welsh translation of "syzygy" appears to be... "syzygy" (to the extent that there is no actual Welsh word for that, hence the default being to utilize a borrow word from English... which would be acceptable in friendly Scrabble play).
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby neufer » Mon Feb 27, 2017 6:02 pm

Chris Peterson wrote:
While "Z" may not exist in traditional Welsh, it is used. In fact, the common Welsh translation of "syzygy" appears to be... "syzygy" (to the extent that there is no actual Welsh word for that, hence the default being to utilize a borrow word from English... which would be acceptable in friendly Scrabble play).

    Well...the whole point was to avoid having to use a blank :!:

    SY_YGY : 8 points in Welsh
    SYZ_GY : 19 points in English
    SYZYGIES : 50 bonus + 24 points in English.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby BDanielMayfield » Mon Feb 27, 2017 6:26 pm

neufer wrote:
BDanielMayfield wrote:At least three of these TRAPPIST-1 planets have already been observed in transit at the same time.

Which three were those :?:

I've been trying to backtrack through the sites I've been reading to find it without success so far, but I saw a graphic last week that showed a TRAPPIST-1 light curve with three partially overlapping transit signals. (For any wishing to help find this info, in addition to this site and Wikipedia I've been reading about this system on the Centauri Dreams and oklo.org websites. Somehow, in following links on one of these sites I was able to peek around Nature's paywall [we no like no stinkin' walls] and I was able to scan a preprint of the discovery paper!) Edit: please disregard the last sentence. See my next post.

It turned out that teasing out overlapping transit signals was a key factor in this seven planet discovery.

Bruce

by "scan" I mean peruse. Wish I had a copy, but I don't. (Now I do, yahoo!) The hole in the wall may have been plugged by now. (and you can too buckaroo.) :cowboy:
Last edited by BDanielMayfield on Mon Feb 27, 2017 9:30 pm, edited 1 time in total.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby BDanielMayfield » Mon Feb 27, 2017 8:38 pm

Ok, still haven't found the light curve graphic, but I did find the paper that I thought was a Nature preprint. It was an ESO public release entitled "Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1" pdf available at http://www.eso.org/public/archives/releases/sciencepapers/eso1706/eso1706a.pdf

To answer Art's question, the three planet overlapping transit was of the b, c and g planets. Edit: Please apend 'I think' to the previous sentence. However, I just found the source of the three overlapping transit graphic! It is one of the hidden figures located on page 23 of the above pdf. This poorly labed graphic is called "Extended Data Figure 1: Light curve of a tripple transit of planets c-e-f" on page 19.

So I think there may have actually been two tripple plays scored so far: b-c-g and c-e-f!

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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby neufer » Mon Feb 27, 2017 10:06 pm

BDanielMayfield wrote:
To answer Art's question, the three planet overlapping transit was of the b, c and g planets. Edit: Please apend 'I think' to the previous sentence. However, I just found the source of the three overlapping transit graphic! It is one of the hidden figures located on page 23 of the above pdf. This poorly labed graphic is called "Extended Data Figure 1: Light curve of a tripple transit of planets c-e-f" on page 19.

So I think there may have actually been two tripple plays scored so far: b-c-g and c-e-f!

Thanks, Bruce.

I wonder if a syzygy of 3 consecutive moons ever happens(...or is that dynamically unstable).
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby BDanielMayfield » Tue Feb 28, 2017 3:16 pm

neuter wrote:I wonder if a syzygy of 3 consecutive moons ever happens(...or is that dynamically unstable).

Er, what are you asking Art? Consecutive how, exactly? And did you mean to moon us here? I thought we were discussing planets. :lol2:
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby Chris Peterson » Tue Feb 28, 2017 3:21 pm

neufer wrote:
BDanielMayfield wrote:
To answer Art's question, the three planet overlapping transit was of the b, c and g planets. Edit: Please apend 'I think' to the previous sentence. However, I just found the source of the three overlapping transit graphic! It is one of the hidden figures located on page 23 of the above pdf. This poorly labed graphic is called "Extended Data Figure 1: Light curve of a tripple transit of planets c-e-f" on page 19.

So I think there may have actually been two tripple plays scored so far: b-c-g and c-e-f!

Thanks, Bruce.

I wonder if a syzygy of 3 consecutive moons ever happens(...or is that dynamically unstable).

The entire system is dynamically unstable, as is any real-world system with more than two bodies. As a rule, I'd think the sort of syzygy you're considering would be a consequence of orbital resonances, which tend to increase metastability.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby neufer » Tue Feb 28, 2017 3:48 pm

Click to play embedded YouTube video.
BDanielMayfield wrote:
neuter wrote:
I wonder if a syzygy of 3 consecutive moons ever happens(...or is that dynamically unstable).
Er, what are you asking Art? Consecutive how, exactly? And did you mean to moon us here? I thought we were discussing planets. :lol2:
Principal McGee: We have pictures of you so-called mooners. And just because the pictures aren't of your faces doesn't mean we can't identify you. At this very moment those pictures are on their way to Washington where the FBI has experts in this type of identification. If you turn yourselves in now, you may escape a Federal charge.
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Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby Douglas » Thu Mar 02, 2017 1:30 pm

"Principal McGee: [color=#0000FF]We have pictures of you so-called mooners. And just because the pictures aren't of your faces doesn't mean we can't identify you."

We've been telling Faux News that for some time, too.

I believe I may have identified our newest president, replete with antlers & "crippled chances" & recent ceremonies with displays of [i]"ekstasis"
[!] ..

Note the sheer number of echoes of current events here ..

http://williamflew.com/omni76a.html

(Quite obviously, All Praise to Harlan Ellison! lol )

douglas

Re: APOD: Seven Worlds for TRAPPIST-1 (2017 Feb 23)

Postby douglas » Sun Mar 12, 2017 12:42 pm

"Although the ultraviolet level is low, the radiation overall is still high enough that it could strip an Earth-like atmosphere from the inner two planets, b and c, in 1 to 3 billion years; for the planets d, e, f, and g (e, f, and g are in the putative habitable zone), the process would take anywhere from 5 to 22 billion years."

"The team found that TRAPPIST-1 emits less than half as much Lyman-alpha radiation as other cool, exoplanet-hosting M dwarfs — including Proxima Centauri, which spews forth six times more in ultraviolet as TRAPPIST-1 does. "

http://www.skyandtelescope.com/astronom ... 603201723/


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