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 Post subject: Re: TRAPPIST-1
PostPosted: Tue, 07-03-17, 20:32 GMT 
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Quote:
Interesting to consider how much we don't know

that's why i am thinking of staying at 2k maps for now

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 Post subject: Re: TRAPPIST-1
PostPosted: Wed, 08-03-17, 14:28 GMT 
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John Van Vliet wrote:
Quote:
Interesting to consider how much we don't know

that's why i am thinking of staying at 2k maps for now


Has my full support, John!

Fridger

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 Post subject: Re: TRAPPIST-1
PostPosted: Thu, 09-03-17, 22:07 GMT 
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Looks like the orbital fit is due for a refinement in the near future courtesy of the K2 mission. Should be able to pin down more details for planet h.

NASA press release: NASA's Kepler Provides Another Peek At Ultra-cool Neighbor


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 Post subject: Re: TRAPPIST-1
PostPosted: Fri, 10-03-17, 19:46 GMT 
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By the way: what star type (I mean not this kind of ultracool dwarf) would be optimal for TRAPPIST-1 planetary habitability? I mean less XUV radiation, but same orbits...


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 Post subject: Re: TRAPPIST-1
PostPosted: Sun, 19-03-17, 14:06 GMT 
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https://arxiv.org/abs/1703.04166

36 pages

18.764 days
0.715 Earth radii
SemiMajorAxis 0.059
Epoch 2457662.55482


Code:

"h" "TRAPPIST-1"
{
   Radius 4555  # radius of 0.715 Earth radii
   Mass 0.377359 # from mass-radius relationship

   Texture "asteroid.*"

   EllipticalOrbit {
      SemiMajorAxis 0.059 
      Period 0.05137303217 # 18.764 days
      Eccentricity 0

      Epoch 2457662.554482 # transit midpoint
      MeanAnomaly 90.000

      ArgOfPericenter 180.000 # unknown, 0 assumed
      Inclination 0.834
      AscendingNode 255.734 # unknown, using ecliptic
   }

   UniformRotation {
      Inclination 0.834 # to match orbit
      AscendingNode 255.734 # to match orbit
   }
}



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 Post subject: Re: TRAPPIST-1
PostPosted: Sun, 19-03-17, 16:29 GMT 
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Many thanks symaski62 for sharing this very interesting paper, which significantly updates our knowledge about the TRAPPIST-1 system!!

Like you also wrote: From this research team we now got the period of planet h's orbit as 18.765 d (a 2:3 resonance configuration with planet g). The radius is found as 0.715 R_E.

Moreover, the researchers find for planet h an equilibrium temperature of 169+-4 K which places it at the snow line.

There is much more interesting info in this paper...

Fridger

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 Post subject: Re: TRAPPIST-1
PostPosted: Sun, 19-03-17, 17:30 GMT 
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Hi,

with the above new data about planet h of the TRAPPIST-1 system, I was able to perfectly reproduce the mid - time of an extreme transit event of planet h (in coincidence with a flare of the star):

From the measurements reported in the paper:
Attachment:
h-transit_measured.jpg
h-transit_measured.jpg [ 45.5 KiB | Viewed 743 times ]


Verification of mid-transit time of planet h in celestia.Sci , in perfect agreement with the observed time:
Barycentric Julian Date - 2457700 = 112.675 [days]

Here is the corresponding screenshot from celestia.Sci at the correct Julian Date of 2457812.675 days
[By all means click on image for a bigger (readable) display]
Attachment:
h-transit.jpg
h-transit.jpg [ 58.97 KiB | Viewed 743 times ]


Enjoy
Fridger

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 Post subject: Re: TRAPPIST-1
PostPosted: Sun, 19-03-17, 18:38 GMT 
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trappist-1(sol) => distance 122 au (19064.90x) celestia.exe

entr transit => 2457812.63970

mid - transit => 2457812.665725 (2017/2/28 03:58:38 UTC)

sort transit => 2457812.69175

:)


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 Post subject: Re: TRAPPIST-1
PostPosted: Sun, 19-03-17, 18:55 GMT 
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symaski62 wrote:
trappist-1(sol) => distance 122 au (19064.90x) celestia.exe

entr transit => 2457812.63970

mid - transit => 2457812.665725 (2017/2/28 03:58:38 UTC)

sort transit => 2457812.69175

:)


Not bad ;-). But I suppose we are both using the same .ssc file (from Andrew).

Fridger

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 Post subject: Re: TRAPPIST-1
PostPosted: Sun, 19-03-17, 21:32 GMT 
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Here is another neat configuration: a double transit of the closest planet b and the most distant planet h, at the measured time. Throughout, I have implemented all new infos about planet h from the above paper:

In Fig. 8 of that paper I scaled up the display and found a measured b-h transit at

BJD - 2457700.00 = 93.905 d

Here is the relevant sniplet from Fig. 8:
Attachment:
b-h_exp.jpg
b-h_exp.jpg [ 11.79 KiB | Viewed 732 times ]

The distance between successive ticks on the x-axis is 5.0 d.

Next I looked for the double transit in celestia.Sci at JD= 2457793.905 d and indeed, find the expected double transit of b and h exactly at this time.
[by all means click on image to obtain a readable display]
Attachment:
b-h_transit.jpg
b-h_transit.jpg [ 81.18 KiB | Viewed 732 times ]


This time the preferences panel is neatly docked on the left in this windowed display. I hope you can read the labels of the two displayed transit disks.

Enjoy,
Fridger

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 Post subject: Re: TRAPPIST-1
PostPosted: Sun, 19-03-17, 22:31 GMT 
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The b h transit confirmed in Celestia 1.6.1


Attachments:
b h transit.jpg
b h transit.jpg [ 74.33 KiB | Viewed 729 times ]

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 Post subject: Re: TRAPPIST-1
PostPosted: Sun, 19-03-17, 22:39 GMT 
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Great Stardust.

This is good news, indicating that things are stable and the simulations are VERY accurate. It is also evident that a lot more serious GUI-based simulation code in this field is ahead of the celestia.Sci dev team ;-) ...

Fridger

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 Post subject: Re: TRAPPIST-1
PostPosted: Mon, 20-03-17, 1:07 GMT 
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https://github.com/rodluger/trappist1

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:D


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 Post subject: Re: TRAPPIST-1
PostPosted: Mon, 20-03-17, 4:02 GMT 
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Thanks symaski62 for the updated ssc code for Trappist-h for Celestia 1.6.1.

Also for all the other info you provided. :clap:

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 Post subject: Re: TRAPPIST-1
PostPosted: Mon, 20-03-17, 4:05 GMT 
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t00fri wrote:
Great Stardust.

It is also evident that a lot more serious GUI-based simulation code in this field is ahead of the celestia.Sci dev team ;-) ...

Fridger


Oh no! I take it all back. :nono: :nono: :nono: :nono:

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