Posted on 01/23/2018 2:23:29 PM PST by Red Badger
A size comparison of the planets of the TRAPPIST-1 system, lined up in order of increasing distance from their host star. The planetary surfaces are portrayed with an artist’s impression of their potential surface features, including water, ice, and atmospheres. Amy Barr's paper “Interior Structures and Tidal Heating in the TRAPPIST-1 Planets” shows that planets d and e are the most likely to be habitable due to their moderate surface temperatures, modest amounts of tidal heating, and because their heat fluxes are low enough to avoid entering a runaway greenhouse state. Planet d is likely covered by a global water ocean. Credit: NASA/R. Hurt/T. Pyle
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Two exoplanets in the TRAPPIST-1 system have been identified as most likely to be habitable, a paper by PSI Senior Scientist Amy Barr says.
The TRAPPIST-1 system has been of great interest to observers and planetary scientists because it seems to contain seven planets that are all roughly Earth-sized, Barr and co-authors Vera Dobos and Laszlo L. Kiss said in "Interior Structures and Tidal Heating in the TRAPPIST-1 Planets" that appears in Astronomy & Astrophysics.
"Because the TRAPPIST-1 star is very old and dim, the surfaces of the planets have relatively cool temperatures by planetary standards, ranging from 400 degrees Kelvin (260 degrees Fahrenheit), which is cooler than Venus, to 167 degrees Kelvin (-159 degrees Fahrenheit), which is colder than Earth's poles," Barr said. "The planets also orbit very close to the star, with orbital periods of a few days. Because their orbits are eccentric –not quite circular – these planets could experience tidal heating just like the moons of Jupiter and Saturn."
"Assuming the planets are composed of water ice, rock, and iron, we determine how much of each might be present, and how thick the different layers would be. Because the masses and radii of the planets are not very well-constrained, we show the full range of possible interior structures and interior compositions." Barr said. The team's results show that improved estimates of the masses of each planet can help determine whether each of the planets has a significant amount of water.
The planets studied are referred to by letter, planets b through h, in order of their distance from the star. Analyses performed by co-author Vera Dobos show that planets d and e are the most likely to be habitable due to their moderate surface temperatures, modest amounts of tidal heating, and because their heat fluxes are low enough to avoid entering a runaway greenhouse state. A global water ocean likely covers planet d.
The team calculated the balance between tidal heating and heat transport by convection in the mantles of each planet. Results show that planets b and c likely have partially molten rock mantles. The paper also shows that planet c likely has a solid rock surface, and could have eruptions of silicate magmas on its surface driven by tidal heating, similar to Jupiter's moon Io.
Explore further: Astrophysicists identify composition of earth-size planets in TRAPPIST-1 system
More information: A. C. Barr et al. Interior structures and tidal heating in the TRAPPIST-1 planets, Astronomy & Astrophysics (2017). DOI: 10.1051/0004-6361/201731992 , On Arxiv: https://arxiv.org/abs/1712.05641
Journal reference: arXiv Astronomy & Astrophysics
Provided by: Planetary Science Institute
But hasn’t it been the goal of man since he stepped out of he cave and looked at the night sky .... To “make it” with a hot alien babe?
“Planet P is clear!”
L
Do you have to travel to the sun to find out what it is made of? As the article already says, because of the nature of the star in question, life might be difficult. We don’t know everything we are capable of discovering about this system. To say we can never know whether life is possible there or has ever been there puts you in with Comte and the patent guy. Never say never.
“Do you have to travel to the sun to find out what it is made of?”
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It’s pretty safe to assume that most stars are made of hot stuff. That’s hardly going out on a limb there.
“because of the nature of the star in question, life might be difficult.”
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Now, that is the type of assumption that I’d cite as not having much basis. The underlying problem is in the assumption that life elsewhere has to the same as it is on earth.
“Never say never.”
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If you have some kind of notion that humans will be zipping from galaxy to galaxy at warp speeds without being burned to a crisp or squished like so many ants, then more power to you.
I enjoy some good sci-fi at times, myself. But humans have real physical limits, so I stick to the science-reality and quantifiable physics involved.
Though I agree that imagining such things can be fun and worthwhile diversion there just are some things man will never do because he just can’t. But we can certainly ponder about them and make hypothesis just for fun.
The star is ‘A’ what?
Well a single light is 6 trillion miles so...uh.... that’s ..24 and a whole bunch of zeros. Forget it. Too far.
In a star system, the biggest or brightest object is labelled ‘A’, as in the Beta Centauri system....................
Pure speculation on “scientific” guesses and assumptions that a tiny few factors of similarities (to earth) spell “possibly habitable” when the requirements for “possibly habitable” require much more than the few known similarities and dozens of facts not in evidence.
I have begun to rate phys.org as I do the History channel on cable TV. And how do I rate the History channel? I refer to it as the speculation channel.
I call it ‘ANYTHING BUT HISTORY Channel’..........Pawn Stars?, really?...................
All because of global warming. /sarc.
Thanks Red Badger.
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