| TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf | |
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+12Rajasun PlutonianEmpire Stalker tommi59 tesh90 Edasich Borislav Mongo Shellface Lazarus Led_Zep zorro83 16 posters |
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Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 15th March 2017, 11:08 pm | |
| - Rajasun wrote:
- Isn't that a little too premature an announcement to make in that we know nothing yet about the atmospheres and gravities of any of the planets in the system?
It was a light-hearted joke... _________________ Caps Lock: Cruise control for 'Cool'!
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Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 19th March 2017, 8:51 pm | |
| Assessing the Habitability of the TRAPPIST-1 System Using a 3D Climate Model https://arxiv.org/abs/1703.05815 - Quote :
- The TRAPPIST-1 system provides an extraordinary opportunity to study multiple terrestrial extrasolar planets and their atmospheres. Here we use the National Center for Atmospheric Research Community Atmosphere Model version 4 to study the possible climate and habitability of the planets in the TRAPPIST-1 system. We assume ocean-covered worlds, with atmospheres comprised of N2, CO2, and H2O, and with orbital and geophysical properties defined from observation. Model results indicate that the inner three planets (b, c, and d) presently reside interior to the inner edge of the traditional liquid water habitable zone. Thus if water ever existed on the inner planets, they would have undergone a runaway greenhouse and lost their water to space, leaving them dry today. Conversely the outer 3 planets (f, g, and h) fall beyond the maximum CO2 greenhouse outer edge of the habitable zone. Model results indicate that the outer planets cannot be warmed despite as much as 30 bar CO2 atmospheres, instead entering a snowball state. The middle planet (e) represents the best chance for a presently habitable ocean-covered world in the TRAPPIST-1 system. Planet e can maintain at least some habitable surface area with 0 - 2 bar CO2, depending on the background N2 content. Near present day Earth surface temperatures can be maintained for an ocean-covered planet e with either 1 bar N2 and 0.4 bar CO2, or a 1.3 bar pure CO2 atmosphere.
_________________ Caps Lock: Cruise control for 'Cool'!
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 30th March 2017, 2:25 am | |
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 3rd April 2017, 9:21 am | |
| A revolution is brewing: observations of TRAPPIST-1 exoplanetary system fosters a new biomarkerhttp://arxiv.org/abs/1703.10803 5. Concluding remarks In this study, we calculated the boundaries of the so called Habeer-table Zone. We showed that planetary ha-beer-tability iscritically dependent on the carbonation level of a potential beer ocean, as well as its degree of alcohol. From this definition, we derived a new combination of biomarkers that should be used in the future - in particular with JWST through transit spectroscopy - to detect and characterize beer planets. We know that Earth-like planets, Jupiler-like planets... are common in our galaxy and by extension in the Universe. Following the discoveries of the TRAPPIST-1 planets, and given the large extent of the Ha-beer-table zone as calculated in our study, beer planets should also be extremely common in our galactic neighborhood. More generally, our work raises the question of how extraterrestrial life would evolve on beer planets. At first sight, beer should be a solvent at least as good as water for life to emerge (Miller 1953). However, we are worried about what form would take natural selection on such planets and if drunk living organisms would really be able to evolve in what we - humans - call the intelligent life paradigm. If beer planets are really common, this is an alternative scenario that should be assessed to solve the Fermi paradox. | |
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Sunchaser Planetesimal
Number of posts : 133 Age : 53 Registration date : 2011-12-23
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 4th April 2017, 8:41 am | |
| Shouldn't that be "Fermented paradox"?
-M- | |
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tommi59 Jovian
Number of posts : 596 Age : 46 Location : Baile Atha Cliath Registration date : 2010-07-31
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 10th April 2017, 3:48 am | |
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tommi59 Jovian
Number of posts : 596 Age : 46 Location : Baile Atha Cliath Registration date : 2010-07-31
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 10th April 2017, 2:43 pm | |
| Assessing spitzer radius for planet h 0.755 earth ,it has density 6.33/cm3 | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 11th April 2017, 7:17 pm | |
| Also interesting to note the conclusions about the state of the ice envelope inferred on TRAPPIST-1f: apparently it is unlikely to be an ocean world. - Quote :
- Using the H2O-REOS equation of state for water (French et al. 2009; Nettelmann et al. 2010) and thermal evolution models of Lopez & Fortney (2014), we find that even at an age of 8 Gyr the temperature at the bottom of such an envelope will be ≳1400K and the pressure will reach ≈130 kbar. For comparison, the pressure in the deepest parts of Earth’s oceans is ≈1 kbar. Moreover, these calculations don’t include the possibility of significant tidal heating from planet-planet interactions, which could raise the interior temperature even higher. At such a high pressure and temperature, water will be far beyond the triple point and far too hot for high pressure ices like ice VII and X. Instead, it will exist as a high pressure molecular fluid, much like the deep interiors of Neptune and Uranus (Fortney et al. 2011; Nettelmann et al. 2011). Therefore, liquid water will likely only exist in clouds near the top of TRAPPIST-1f’s atmosphere and our results suggest that it is no more likely to be habitable than any other gas or ice-giant with water clouds in its atmosphere.
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tommi59 Jovian
Number of posts : 596 Age : 46 Location : Baile Atha Cliath Registration date : 2010-07-31
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 12th April 2017, 3:07 am | |
| Radius for planet h 0.715⊕ is taken from K2 data so for some other planets from the same data is b 0,95⊕ c 1,14⊕ d 0.59⊕ e 0.95⊕ | |
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matthew27 Micrometeorite
Number of posts : 12 Registration date : 2015-02-09
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 12th April 2017, 4:34 am | |
| - Lazarus wrote:
- Also interesting to note the conclusions about the state of the ice envelope inferred on TRAPPIST-1f: apparently it is unlikely to be an ocean world.
- Quote :
- Using the H2O-REOS equation of state for water (French et al. 2009; Nettelmann et al. 2010) and thermal evolution models of Lopez & Fortney (2014), we find that even at an age of 8 Gyr the temperature at the bottom of such an envelope will be ≳1400K and the pressure will reach ≈130 kbar. For comparison, the pressure in the deepest parts of Earth’s oceans is ≈1 kbar. Moreover, these calculations don’t include the possibility of significant tidal heating from planet-planet interactions, which could raise the interior temperature even higher. At such a high pressure and temperature, water will be far beyond the triple point and far too hot for high pressure ices like ice VII and X. Instead, it will exist as a high pressure molecular fluid, much like the deep interiors of Neptune and Uranus (Fortney et al. 2011; Nettelmann et al. 2011). Therefore, liquid water will likely only exist in clouds near the top of TRAPPIST-1f’s atmosphere and our results suggest that it is no more likely to be habitable than any other gas or ice-giant with water clouds in its atmosphere.
Bad news for the habitability of planet F...Is there any good news for D, E or G? | |
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 12th April 2017, 5:12 am | |
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Daniel SuperEarth
Number of posts : 272 Registration date : 2009-11-14
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 12th April 2017, 2:21 pm | |
| Still not enough to rule out the life possibility in one of planets in the habitable zone
First TRAPPIST-1f e g for example like other planets of this system it's very likely to getting energy also by gravitational tidal heating plus the star energy to keep an ocean liquid
Second Frequent flaring it's likely to not be a barrier for a ocean world even if one of this planets has continents life from this ocean it's likely to adapt the surface by the evolution as we know it.
third it's seems that planets around flare stars can keep the atmosphere see the GJ1132b case.
So in the end of the day it's too early to jump for conclusions and rule out this planets and others similar system in the Galaxy of the potential planets with life.
Last edited by Daniel on 13th April 2017, 4:09 am; edited 2 times in total | |
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tommi59 Jovian
Number of posts : 596 Age : 46 Location : Baile Atha Cliath Registration date : 2010-07-31
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 12th April 2017, 4:09 pm | |
| If GJ 1132 b has atmosphere being closer to its host which is much larger and hotter than Trappist 1 so all planets around this very small star which are potentially habitable d ,e ,f, g surely have atmospheres.We do not know exact mass of planet f to judge habitability now and I wonder why error bars for mass of this planet is so small comparing to other planets in this system | |
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Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 16th April 2017, 8:35 pm | |
| _________________ Caps Lock: Cruise control for 'Cool'!
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Daniel SuperEarth
Number of posts : 272 Registration date : 2009-11-14
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 17th April 2017, 4:30 am | |
| This last paper seems that all planets are kind gas mini-Neptune planets,I have my doubts about it,specially for the one near to the star,prefer wait for radial velocity confirm it. | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 17th April 2017, 4:52 pm | |
| A high volatile content wouldn't be entirely surprising, especially if the planets migrated inwards to their current orbits. Interesting discrepancy in the masses though. | |
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tommi59 Jovian
Number of posts : 596 Age : 46 Location : Baile Atha Cliath Registration date : 2010-07-31
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 18th April 2017, 4:09 am | |
| New mass measurement are kind of joke how it is possible these planets have so low densities similar to Neptune? It would requires 70% of water content for e,f,g planets. Large discrepancy between b and c planets is weird but between c and g with similar radius is even weirder.I do not buy it
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 17th May 2017, 6:48 pm | |
| Another take on atmospheric loss from the TRAPPIST-1 planets: Dong et al. "Atmospheric escape from the TRAPPIST-1 planets and implications for habitability" https://arxiv.org/abs/1705.05535Not surprisingly, g and h are the best candidates for maintaining an atmosphere over Gyr timescales. | |
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tommi59 Jovian
Number of posts : 596 Age : 46 Location : Baile Atha Cliath Registration date : 2010-07-31
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 18th May 2017, 5:43 am | |
| Conclusion from this paper : planets b,d,e,f can not have such low densities reported recently as all volatile substances (H,He) and water would be gone | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 22nd May 2017, 1:54 pm | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 17th June 2017, 4:35 am | |
| More challenges to atmospheric stability on the TRAPPIST-1 planets... Garraffo et al. "The Threatening Environment of the TRAPPIST-1 Planets" https://arxiv.org/abs/1706.04617 - Quote :
- This is a new regime not experienced in solar system planets: there is no magnetopause at which the planetary field pressure balances the wind pressure. Instead, stellar wind particles can constantly precipitate directly down open field onto the atmosphere. The concept of atmospheric protection by a planetary magnetic field does not hold here and is likely not to hold in the conventional sense for the TRAPPIST-1 planets. The TRAPPIST-1 system represents a new challenge to atmospheric evolution and survival on close-in planets around very low mass stars.
Interesting to consider how a mini-Neptune would survive under these conditions. | |
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 10th August 2017, 3:05 am | |
| Astrometric search for outer gas giants: no planet above 4.6 Jupiter masses with a 1-year orbit, no planet above 1.6 Jupiter masses in 5-year orbits. Boss et al. "Astrometric Constraints on the Masses of Long-Period Gas Giant Planets in the TRAPPIST-1 Planetary System" https://arxiv.org/abs/1708.02200Not entirely surprising given that massive planets may be disruptive to multi-resonant configurations like TRAPPIST-1. | |
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Led_Zep SuperJovian
Number of posts : 721 Location : France Registration date : 2011-09-09
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 31st August 2017, 11:04 am | |
| https://www.spacetelescope.org/news/heic1713/Hubble delivers first hints of possible water content of TRAPPIST-1 planetsAn international team of astronomers used the NASA/ESA Hubble Space Telescope to estimate whether there might be water on the seven earth-sized planets orbiting the nearby dwarf star TRAPPIST-1. The results suggest that the outer planets of the system might still harbour substantial amounts of water. This includes the three planets within the habitable zone of the star, lending further weight to the possibility that they may indeed be habitable | |
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Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 31st August 2017, 5:42 pm | |
| That's fantastic news. They may not be bone-dry irradiated, atmosphere-less rocks. Edit: It doesn't look like this is being reported very clearly. HST did not detect anything related to water content in the planets. It just refined the star's luminosity and set evolutionary constraints on the water content of the planets. _________________ Caps Lock: Cruise control for 'Cool'!
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Lazarus dF star
Number of posts : 3337 Registration date : 2008-06-12
| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf 1st September 2017, 4:24 am | |
| Yeah, pretty misleading headline that. Constraint on the UV-output of the star is an important factor here but the relationship to water on the planets is quite indirect. Paper from that press release is now also on arXiv: https://arxiv.org/abs/1708.09484 | |
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| Subject: Re: TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf | |
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| TRAPPIST-1 : Transiting Earth-Sized Planets Around a Nearby Ultracool Dwarf | |
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