TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by Lazarus on 5th July 2018, 1:52 pm

Planet e has gone down a bit though. Wonder if it's still rocky.
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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by tommi59 on 5th July 2018, 5:56 pm

Well densities of the planets look now planet b 4.81 ,c -5.23, d-4.23, e 4.80, f- 4.66, g- 4.61 , h- 4.39 g/cm3 so all depends on Fe %, Mg % ,water and other factors, nevertheless some of them can contain up to 3 % of water assuming 32 % Fe (earthlike composition) In this case e and c have very similar composition to Venus and may contain little bit more water than Earth can have some land but almost entirely covered by ocean .Planets b and f have almost identical composition but surely require to have water 1-1.5 %. Planet g has the most water of all but not more than 3%.Planet d after revised mass still requires water but much less maybe even less than 0.1%. Planet h has not more than twice water than Earth so is not completely covered by water. Assuming lower Fe % than 32 for example 20 all planets might be waterless even g
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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by tommi59 on 18th July 2018, 7:15 am

Not sure if such paper appeared here before,
https://www.researchgate.net/publication/323904896_Spin-orbital_Tidal_Dynamics_and_Tidal_Heating_in_the_TRAPPIST-1_Multiplanet_System?_sg=ZgK6QQg-CDoEX9gdc5I_5IUgQUxB-9E09Ww4Noi7wP6s6N37effeA64KmWTlTrWFX-8mgd2Rgw

I have a question about slope of the planet's axis in case of tidal locking and capture in 1:1 and 3:2 resonance? Would Earth and Mars loose completely their 23.4 and 25,2 % slope or decrease only if being in habitable zone of trappist 1 system? After all it has influence on habitability
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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by tommi59 on 25th July 2018, 2:46 am

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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by tommi59 on 10th August 2018, 4:48 am

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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by Lazarus on 14th August 2018, 1:07 pm

Dorn et al. "Interior characterization in multiplanetary systems: TRAPPIST-1"
https://arxiv.org/abs/1808.01803

More models of the TRAPPIST-1 planetary bulk compositions.
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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by tommi59 on 14th August 2018, 2:23 pm

In this paper mass measurement are from Grimm not Demory slides from Exoplanets 2 .I am curious when any paper of it is going to appear ?
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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by Sirius_Alpha on 23rd September 2018, 9:08 pm

Planet-Planet Tides in the TRAPPIST-1 System
https://arxiv.org/abs/1809.08166

The star TRAPPIST-1 hosts a system of seven transiting, terrestrial exoplanets apparently in a resonant chain, at least some of which are in or near the Habitable Zone. Many have examined the roles of tides in this system, as tidal dissipation of the orbital energy of the planets may be relevant to both the rotational and orbital dynamics of the planets, as well as their habitability. Generally, tides are calculated as being due to the tides raised on the planets by the star, and tides raised on the star by the planets. I write this research note to point out a tidal effect that may be at least as important as the others in the TRAPPIST-1 system and which is so far unremarked upon in the literature: planet-planet tides. Under some reasonable assumptions, I find that for every planet p in the TRAPPIST-1 system there exists some other planet q for which the planet-planet dynamical tidal strain is within an order of magnitude of the stellar eccentricity tidal strain, and that the effects of planet f on planet g are in fact greater than that of the star on planet g. It is thus not obvious that planet-planet tides can be neglected in the TRAPPIST-1 exoplanetary system, especially the tides on planet g due to planet f, if the planets are in synchronous rotation.

The assertion that planet-planet tides have not been considered for the case of TRAPPIST-1 appears to be refuted by the existence of this paper.

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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by Lazarus on 25th September 2018, 1:35 am

Sirius_Alpha wrote:The assertion that planet-planet tides have not been considered for the case of TRAPPIST-1 appears to be refuted by the existence of this paper.
This reference is now added in v2 of the arXiv paper.
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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by Lazarus on 29th October 2018, 4:11 pm

A couple of conference proceedings about the TRAPPIST-1 system:

Breton et al. "Tidal heating in multilayer planets: Application to the TRAPPIST-1 system"
https://arxiv.org/abs/1810.11254

Bolmont "Constraining the environment and habitability of TRAPPIST-1"
https://arxiv.org/abs/1810.11255
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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

Post by tommi59 on 13th November 2018, 7:30 am

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Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf

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