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#76 2022-10-03 09:09:08

Mars_B4_Moon
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Registered: 2006-03-23
Posts: 9,761

Re: Extrasolar Habitable Planets

Earthlike Worlds With Oceans and Continents Could be Orbiting red Dwarfs, Detectable by James Webb

https://www.universetoday.com/157911/ea … ames-webb/

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#77 2022-10-03 10:25:26

Calliban
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From: Northern England, UK
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Re: Extrasolar Habitable Planets

Based upon findings so far, our solar system appears to be unusual.  The terrestrial planets are relatively small due to the influence of Jupiter early in their development.  They have water, but not too much.  And they have wide orbits.  Wide enough to allow Earth to posses its own moon.

As a rule, other planetary systems appear to be much closer in, with orbital radii more comparable to those of moons of our giant planets.  Exoplanets are all generally much larger than our terrestrial planets.  This doesn't bode well for extraterrestrial life.  Most worlds will have deep, high pressure atmospheres.  And if a civilisation does evolve on a super-Earth with several Earth masses, it is trapped in a gravitational prison.  Even with nuclear pulse propulsion, it woukd be difficult to climb out of a gravity well as steep as that.  What we have learnt so far imposes seriously constraints on the Drake equation.


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#78 2022-10-05 07:10:31

Mars_B4_Moon
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Registered: 2006-03-23
Posts: 9,761

Re: Extrasolar Habitable Planets

Different to a double planet also known as binary planet but maybe described Like something from a scifi book or movie tv show Twin planets of Habitation not just of Heat Fire and Water Ice,  Dispossed by Ursula K Le Guin, Rocheworld flight of the Dragonfly, Land and Overland by Robert "Bob" Shaw mentioned twin planets or two worlds and so did a tv show called 'Alf' and Phoresis by Greg Egan


Exoplanet LP 890-9c: Probably particularly life-friendly super-Earth discovered
https://www.heise.de/news/Exoplanet-LP- … 58770.html

Discovery of Two Temperate Super-Earths, the Outer One Orbits in the Habitable Zone
https://subarutelescope.org/en/results/ … /3089.html

A Rocky 'Super-Earth' in the Habitable Zone
https://exoplanets.nasa.gov/news/1712/d … able-zone/

Fun facts: The new planet, LP 890-9 c, adds to the list of worlds discovery teams suggest might be examined by the James Webb Space Telescope. Launched in December 2021, the telescope has settled into its orbit a million miles from Earth and already has begun reading out the gases present in exoplanet atmospheres. The telescope’s instruments include spectrographs, which can capture light shining from a parent star through the atmospheres of exoplanets, providing a spectrum and a fingerprint of the types of gases present. That, and other methods the telescope uses to analyze atmospheres, potentially could reveal which of these planets might be habitable worlds.

The study authors say the new planet is especially promising for potential atmospheric studies; in fact, the study says, it is “the second-most favorable habitable-zone terrestrial planet” after the TRAPPIST-1 planetary system – seven roughly Earth-sized planets about 40 light-years away, including three in the habitable zone of their red-dwarf star.

The discoverers: The new planet is detailed in a paper published by an international team of scientists led by Laetitia Delrez, an astrophysicist at the University of Liège, Belgium. It was entered into NASA’s Exoplanet Archive on Sept. 16, 2022.

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#79 2022-10-09 15:11:16

Mars_B4_Moon
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Re: Extrasolar Habitable Planets

relevant to news on Exoplanets



A Solar Gravitational Lens Will be Humanity's Most Powerful Telescope. What are its Best Targets?

https://www.universetoday.com/157983/a- … t-targets/

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#80 2022-10-11 05:19:40

Mars_B4_Moon
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Re: Extrasolar Habitable Planets

When Volcanoes, Caves, Lava Tubes are too far away to study

Engineers made synthetic alien lava to understand uninhabitable worlds
https://www.popsci.com/science/syntheti … xoplanets/

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#81 2022-10-15 19:43:53

Void
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Registered: 2011-12-29
Posts: 7,285

Re: Extrasolar Habitable Planets

Well, I really enjoyed this article: https://www.space.com/habitable-rocky-p … ed-by-land

Yes, they say that the land dominated worlds have more flexibility as per location in the habitable zone.  This type of world sort of fits with the possibility of having a small sea on the dark side of a tidal locked world.  Maybe.  Maybe one with a little part that peeks into the sunlight?

Anyway, that would be a weird world to live on.  However, for a world that humans might eventually inhabit, the lots of dry land exposed to light for solar energy, and perhaps also some spreading rift valleys not so much covered with water, where geothermal might be usefully available.

I wonder though if these worlds get ejected, would they then collect more Hydrogen as Rogue planets, and the so over time accumulate more water, as venting from Volcanic actions might mix with the Hydrogen.

Where planet 9 is thought to perhaps be a Super Earth, (Or not exist at all), might it be of a dry or wet variation?  Might it have exposed spreading seafloor fractures like the Midatlantic ridge?  If so then could humans tap into that as an energy source.  Better if it is not a Super Earth, or maybe Super Earth with a Super Moon.

Not likely, but some interesting Sci Fi places to think about.



Done.

Last edited by Void (2022-10-15 19:59:11)


Done.

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#82 2022-10-16 12:32:09

Mars_B4_Moon
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Re: Extrasolar Habitable Planets

If we Detect This gas on Other Planets, it’s a Good Sign There’s Life There

https://www.universetoday.com/158102/if … ife-there/

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#83 2022-10-17 19:24:21

Void
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Registered: 2011-12-29
Posts: 7,285

Re: Extrasolar Habitable Planets

I am really liking what I am seeing on these:

Rogue Planets:

https://www.bing.com/videos/search?q=Ar … ORM=WRVORC

https://www.bing.com/videos/search?q=Ar … &FORM=VIRE

Going to view them again prior to comments, so pause.................


Done.

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#84 2022-10-17 19:49:13

Void
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Registered: 2011-12-29
Posts: 7,285

Re: Extrasolar Habitable Planets

I am really liking what I am seeing on these:

Rogue Planets:

https://www.bing.com/videos/search?q=Ar … ORM=WRVORC

https://www.bing.com/videos/search?q=Ar … &FORM=VIRE

So, it becomes interesting to think that rather than going star to star, humans might eventually be able to jump from planet to planet all the way across the galaxy.

I am quite sure that many such planets would be a challenge and then some.

Some interesting cases might be a "Super Jupiter", which would be a very small old brown dwarf?  If it had a solar system like that of Jupiter's, would you have a possibility of an Io, Europa, Ganymede, and Callisto?

Would these moons attach an atmosphere of Hydrogen?  I am presuming that the Super Jupiter Rogue Planet would not have a solar wind to sweep it away.

For Humans an atmosphere of ~.33 bar to 5 bar might be OK???  5 bar would be a high pressure for humans but perhaps tolerable.

The Trappiest planets may also be heated by tidal heating, so finding a "Super Jupiter Rogue Planet" with tidal heated Planet/Moons would not be impossible.

As our IO is now, it might likely spew its atmosphere away, until it got wet from Hydrogen bonding with Oxygen.  Then perhaps the volcanism could be contained within an atmosphere.  So, there might be a lot of hot spots to get geothermal energy from.

As for Europa and the other two moons, with an atmosphere, the ice layers on them might be thinner.  Maybe for Europa, even open water, if say a 10-100 bar atmosphere???

But the Rogues might also be like Pluto or like Ceres.  Or they could be a Venus that has frozen it's CO2 and Nitrogen.  However, if such a planet did gather Hydrogen, then it's CO2 would bond with it and create water and Hydrocarbons.  And as for the Nitrogen, how many bars of Hydrogen would you need to vaporize it beneath a Hydrogen atmosphere?  I am sure if there were 10 to 100 bars of Hydrogen, then the Nitrogen is likely to be evaporated under it.

And then I have been pounding the drum for Fusion.  It is possible that these planets will naturally concentrate Heavy Hydrogen.  If a fusion process is possible as currently conceived, then these worlds would be very habitable.

But we do know that we can make Hydrogen Bomb reactors.  This would be like Orion Propulsion methods, with them being set off in sequence, perhaps in a body of water the size of the Caspian Sea????  Now if you could cascade it into a Helium 3 bomb(s), then it would be aneutronic with much less radiation problems.

When your world is in a solar wind, then the Hydrogen will tend to be blown away, if it is a low gravity planet.  But out beyond, it may be that there are large pools of atmosphere containing Heavy Hydrogen and those planets may also have Helium 3.

Almost paradise, for a sufficiently advanced so-called civilization, I would think.

Some Rogues may be very old planets, as having showed up a long time ago, or they might be cast off from white dwarf stars.

https://www.syfy.com/syfy-wire/bad-astr … ting-chaos

Well, some of their planets may be eaten, but if our sun became white dwarf, then it would lose a lot of mass, and perhaps some planets, dwarf planets will spin away from it.

It might be similar to Phobos and Deimos.  Phobos, is expected to crash into Mars, Deimos is expected to spin off of Mars eventually.

A little more fun here: I would say that if heavy Hydrogen and perhaps Helium 3 were available in a white dwarf system, then habitation of it and manipulation of its remnants might make sense for a so-called civilization.  It might actually be a target of opportunity.

------

I might think that to travel to a Rogue or a White Dwarf from a Rogue, perhaps Orion Ships for multi generations might make sense.

Done.

Last edited by Void (2022-10-17 20:20:43)


Done.

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#85 2022-10-18 11:25:32

Void
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Re: Extrasolar Habitable Planets

It seems likely that by adapting to the outer solar system, then the Kuiper Belt, then the Oort Cloud, methods should emerge that will allow further distributions to Rogue objects of various sorts.

smile

Done.


Done.

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#86 2022-10-19 18:33:06

Void
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Registered: 2011-12-29
Posts: 7,285

Re: Extrasolar Habitable Planets

I have been thinking about many things including brown dwarfs.

https://www.jpl.nasa.gov/news/powerful- … rown-dwarf
Quote:

Given that there's no stellar wind to create an aurora on a brown dwarf, researchers are unsure what is generating it on LSRJ1835+3259. An orbiting planet moving through the magnetosphere of the brown dwarf could be generating a current, but scientists will have to map the aurora to figure out its source.

https://www.nasa.gov/feature/jpl/in-a-f … rown-dwarf
Image Quote: https://www.nasa.gov/sites/default/file … k=tRoZeerT

L-Dwarfs apparently burn up the Deuterium and Lithium that they are born with and then stop fusing: https://www.youtube.com/watch?v=-b1jJ_0pwI8

I have been wondering if an L-Dwarf can again accumulate more mass, including Deuterium and Lithium, if it should wander into a denser galactic cloud.  If that were the case, then these stars might do just a little bit of fusing even after they had burned their birth inheritance of the substances.  But I don't know that that is the case.

The whole idea of worlds around brown dwarf stars seems very interesting.  And it is considered that these may have planets closer to terrestrials in size.  Those may have tidal heating and may also have their own moons, I presume.

Aluminum 26.  I am probably trying to punch far above my weight, but if the notions given in this article are true for Brown Dwarf Stars as well as it may have been true for our star, then we might expect some dried-out planets.  They may not be all ice balls.

Also, I wonder if still materials can accrete to brown dwarfs as they apparently do not have a solar wind, could there be a steady but low production of Aluminum 26?  Might some of that make it to the planets that may orbit the brown dwarf?

https://mcdonaldobservatory.org/news/releases/20200728
Quote:

Offner’s team has proposed an explanation that does not require an outside source. They propose that aluminum-26 formed close to the young Sun, in the inner part of its surrounding planet-forming disk. As material fell from the disk’s inner edge onto the Sun, it created shockwaves that produced high-energy protons known as cosmic rays.

Leaving the Sun at nearly the speed of light, the cosmic rays slammed into the surrounding disk, colliding with the isotopes aluminum-27 and silicon-28, changing them into aluminum-26.

Due to its very short half-life of about 770,000 years, aluminum-26 must have been formed or mixed into the young Sun's surrounding planet-forming disk shortly before the condensation of the first solid matter in our solar system. It plays an important part in the formation of planets like Earth, since it can provide enough heat through radioactive decay to produce planetary bodies with layered interiors (like Earth’s solid core topped by a rocky mantle and above that, a thin crust). The radioactive decay of aluminum-26 also helps to dry out early planetesimals to produce water-poor, rocky planets.

We seem to have an ecosystem in the sub oceanic bottoms that feeds life with radioactive decay.  A continuing input of Aluminum 26 and other decay items might "Feed" life in liquid water on such planets.  Even at -20 degC, is life in Antarctica that can feed off of atmospheric gasses.

This might greatly aid a galactic Panspermia, if there were many abodes that can harbor life.

Hydrothermal is one I recall mentioned by Spacenut: https://phys.org/news/2021-11-possibili … ocean.html

But radioactive decay in the sediments can produce products that can support life, such as Hydrogen.

Here is an article: https://www.theatlantic.com/science/arc … ds/619030/
Quote:

Two papers published in February by different research groups seem to have solved some of this mystery for cells beneath the continents and in deep marine sediments. They show evidence that, much as the sun’s nuclear-fusion reactions provide energy to the surface world, a different kind of nuclear process—radioactive decay—can sustain life deep below the surface. Radiation from unstable atoms in rocks can split water molecules into hydrogen and chemically reactive peroxides and radicals; some cells can use the hydrogen as fuel directly, while the remaining products turn minerals and other surrounding compounds into additional energy sources.

Although these radiolytic reactions yield energy far more slowly than the sun and underground thermal processes, the researchers have shown that they are fast enough to be key drivers of microbial activity in a broad range of settings—and that they are responsible for a diverse pool of organic molecules and other chemicals important to life. According to Jack Mustard, a planetary geologist at Brown University who was not involved in the new work, the radiolysis explanation has “opened up whole new vistas” into what life could look like, how it might have emerged on an early Earth, and where else in the universe it might one day be found.

So, if the inertia of materials dropped into a brown dwarf can create cosmic rays, perhaps a small trickle of radioactive materials produced may drop into planets that may exist around brown dwarf stars, and this may have the potential to feed life, and maybe even keep those planets warmer????

Well, it is a very long reach for a shorty like me.  But I like the notion.

Done.

Last edited by Void (2022-10-19 19:18:01)


Done.

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#87 2022-10-21 11:18:54

Void
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Registered: 2011-12-29
Posts: 7,285

Re: Extrasolar Habitable Planets

I do not obsess about finding alien life, I guess that can be left to those who will.

I am not intimidated by planets presumed to not have an atmosphere: https://phys.org/news/2022-10-discovery … tures.html

The planet mentioned, is slightly larger than Earth, appears to have no atmosphere, so it is not a Venus type.

Supposing humans do latch on to tech that can get them to other worlds.  A Venus would likely be the least useful in most cases.

We do not know if this planet is tidal locked, or if its rotation poles are going to provide shadowed craters at them.

But really, no surprise that this planet does not hold an atmosphere:

The radiation revealed the planet's scorching daytime temperatures, estimated to reach 2,242 degrees Fahrenheit—so hot that gold, silver, and copper would all melt on the planet. The heat, coupled with assumed low surface pressure, led the researchers to believe there's no atmosphere.

If I consider Proxima-d, I like what I think may be: https://en.wikipedia.org/wiki/Proxima_Centauri_d
Quote:

Proxima Centauri d
From Wikipedia, the free encyclopedia
Jump to navigationJump to search
Proxima Centauri d
Artist’s impression of Proxima d (close-up).jpg
Artistic depiction of Proxima Centauri d, with Proxima Centauri and Alpha Centauri A & B visible in the background
Discovery[1]
Discovery site    VLT-ESPRESSO
Discovery date    2020
Detection method    Radial velocity
Orbital characteristics[1]
Semi-major axis    0.02885+0.00019
−0.00022 AU
Eccentricity    0.04+0.15
−0.04
Orbital period (sidereal)    5.122+0.002
−0.0036 d
Semi-amplitude    0.39±0.07 m/s
Star    Proxima Centauri
Physical characteristics[1]
Mean radius    ≙0.81±0.08 R?
Mass    ≥0.26±0.05 M?
Temperature    360 K (87 °C; 188 °F)
Proxima Centauri d (also called Proxima d) is a candidate exoplanet orbiting the red dwarf star Proxima Centauri, the closest star to the Sun and part of the Alpha Centauri triple star system. Together with two other planets in the Proxima Centauri system, it is the closest known exoplanet to the Solar System, located approximately 4.2 light-years (1.3 parsecs; 40 trillion kilometres; 25 trillion miles) away in the constellation of Centaurus. The first signs of the exoplanet emerged as a weak 5.15-day signal in radial velocity data taken from the Very Large Telescope during a 2020 study on Proxima b's mass. This signal was formally proposed to be a candidate exoplanet by Faria et al. in a follow-up paper published in February 2022.[2][1]

Proxima d is a sub-Earth at least one-quarter of the mass of Earth (or twice the mass of Mars), orbiting at roughly 0.029 AU (4.3 million km; 2.7 million mi) every 5.1 days.[2] It is the least massive and innermost known planet of the Proxima Centauri system. It is the least massive exoplanet detected with the radial velocity method as of 2022. Proxima d orbits too close to its star to be habitable—assuming an Earth-like reflectivity, its equilibrium temperature may reach 360 K (87 °C; 188 °F).[1]

So, the obsessive worry about a planet not holding an atmosphere might be bas akward, to those who might want to know what kind of world is of interest.  If 'd' is at risk of loosing it's atmosphere, then that is a good thing.  It will not be a Venus analog.

If it is a Mercury analog, then there should be special resources such as Ice, Dry Ice, and Ammonia in shadowed craters, (Maybe).

If it is tidal locked, then there should be such materials on the dark side of that planet.

The energy available on the day sides of these planets will make them attractive.  Presuming the volatile materials as ices on the dark side of the planet then good.  A low gravitation is probably preferred.

To me then 'd' is more attractive than 'b': https://en.wikipedia.org/wiki/Proxima_Centauri_b

But of course, we absolutely do not know if humans and/or their machines can or will travel to such worlds.  Just now it is looking very iffy.

Done.

Last edited by Void (2022-10-21 11:31:06)


Done.

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#88 2023-02-15 16:16:38

Mars_B4_Moon
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Posts: 9,761

Re: Extrasolar Habitable Planets

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#89 2023-02-20 10:55:13

Mars_B4_Moon
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Registered: 2006-03-23
Posts: 9,761

Re: Extrasolar Habitable Planets

Researchers Focus AI On Finding Exoplanets

https://spaceref.com/science-and-explor … xoplanets/

The first exoplanet was found in 1992, and though more than 5,000 are known to exist, those have been among the easiest for scientists to find. Exoplanets at the formation stage are difficult to see for two primary reasons. They are too far away, often hundreds of lights years from Earth, and the discs where they form are very thick, thicker than the distance of the Earth to the sun. Data suggests the planets tend to be in the middle of these discs, conveying a signature of dust and gases kicked up by the planet.

The research showed that artificial intelligence can help scientists overcome these difficulties.

“This is a very exciting proof of concept,” said Cassandra Hall, assistant professor of astrophysics, principal investigator of the Exoplanet and Planet Formation Research Group, and co-author on the study. “The power here is that we used exclusively synthetic telescope data generated by computer simulations to train this AI, and then applied it to real telescope data. This has never been done before in our field, and paves the way for a deluge of discoveries as James Webb Telescope data rolls in.”

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#90 2023-02-21 07:21:36

Mars_B4_Moon
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Re: Extrasolar Habitable Planets

some Exoplanet news

United Press International (UPI) is an American international news agency but owned by 'Moonies'  purchased by News World Communications, an international news media company founded in 1976 by Unification Church leader Sun Myung Moon.

https://www.upi.com/Science_News/2023/0 … 676931396/

'Very Large Telescope captures direct images of bright exoplanet'

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#91 2023-02-22 10:37:01

Mars_B4_Moon
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Re: Extrasolar Habitable Planets

Hycean Planets & Ice Worlds | Isaac Arthur
https://isaacarthur.net/video/hycean-planets-ice-worlds

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#92 2023-02-24 20:09:03

Void
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Registered: 2011-12-29
Posts: 7,285

Re: Extrasolar Habitable Planets

Something else from Isaac Arthur: https://www.bing.com/videos/search?q=Is … M%3DHDRSC3
Quote:

Journey to Alpha Centauri
YouTube15.7K views1 day ago
Isaac Arthur

I just got done with my first intense workout since I got sick about 2 weeks ago, so I just want to float, and not struggle.  So, I will do this, which of course for someone my age is mostly fantasy and entertainment.

I am interested in how we see things.  Like most people I have been of the opinion that making new "Earths" is the desire.  But over time I have begun to think that a world has its own values.  While you might modify it to be more useful, I think trying to make them totally like Earth, is more of a burden than a benefit.

When thinking about Proxima Centauri and Alpha A and B, questions i now have are do they have something like the asteroid belt?

I have recently come to understand that what is between Jupiter and Mars, is of the greatest value.  You can include Mars/Phobos/Deimos into that.  These seem to be of a "Blended" family.

A mixture of outer solar system ices with rock and inner solar system rock with ices (Sometimes).

Not being able to know about that?  I will query.

Pardon Me! https://www.popularmechanics.com/space/ … of%20Pluto.
Quote: gallery-1509718175-eso1735a.jpg?resize=1200:*
So, I guess at the time of this article 'C' and 'D' planets were not considered.
Quote:

Its one confirmed planet, Proxima b, orbits much closer to the star than the dust belt, at just 2.5 million miles (4 million kilometers), which is only about 0.03 AU. The inner and outer dust belts of Proxima Centauri bear similarities to the asteroid belt between Mars and Jupiter and the Kuiper belt out beyond the orbit of Pluto.

So, 'b' and 'd' may be the inner solar system, and then maybe an asteroid belt, and I am not sure, but perhaps 'c' outside the asteroid belt and then there appears to be something similar to the Kuiper belt.

So, the first place to hope to go too might be in the pseudo-Kuiper belt or the Pseudo Asteroid belt.  In the first case you need fusion, in the second case mirrors might do.

So, unless you stopped in the Pseudo Kuiper belt, you might hope for a Pseudo Ceres in the Pseudo Asteroid belt.

Planet 'c' might have a tidally heated moon like Enceladus or Europa.

Of the two inner planets 'b' and 'd', I am much more interested in 'd'.  The planets may well not have atmospheres, but may have lots of ices in the dark parts, polar craters, or tidal locked dark side.

'b' has much more gravity.

So, then 'd'

https://en.wikipedia.org/wiki/Proxima_Centauri_d
Quote:

Proxima d is a sub-Earth at least one-quarter of the mass of Earth (or twice the mass of Mars), orbiting at roughly 0.029 AU (4.3 million km; 2.7 million mi) every 5.1 days.[2] It is the least massive and innermost known planet of the Proxima Centauri system. It is the least massive exoplanet detected with the radial velocity method as of 2022. Proxima d orbits too close to its star to be habitable, and receives about 190% of Earth's irradiation—assuming an Earth-like reflectivity, its equilibrium temperature may reach 360 K (87 °C; 188 °F).[1]

Just on a guess, 40% of the planets surface might be covered in ice and a subsurface liquid sea may exist, or might be possible to create.

And the front side could be made in to a giant collection of heat engines to power the world.

Isaac Arthur's video implies to me that it could be eventually terraformed more, with an atmosphere and protections a magnetic field, and shading, and mirrors to light up the dark side.

I guess I could agree with that.

So, some options for that solar system, I guess.

Done.

Well, here is another article about such asteroid belts: https://planetpailly.com/2020/03/03/tou … oid-belts/  Quote: mr03-proxima-centauri-system.jpg?w=521

'c' is about as cold as Pluto, so I guess only the inner belt could host mirrors as power plants, (Probably).

'd' is not shown but if it exists it would be inside of 'b''s orbit.

Done.

Well it appears that 'd' likely exists, and is considered to be in the "Habitable" zone.

https://astronomy.com/news/2022/02/thir … a-centauri
Quote:

Third exoplanet found around closest star to Earth
The planetary family around Proxima Centauri, the closest star to Earth, just keeps growing.
By Alison Klesman  |  Published: Monday, February 21, 2022
RELATED TOPICS: EXOPLANETS

So, really it being a flare star is not really a problem presuming your spaceships and habitats have proper protection.

Done.

Last edited by Void (2023-02-24 20:58:18)


Done.

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#93 2023-02-28 11:20:19

Mars_B4_Moon
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Registered: 2006-03-23
Posts: 9,761

Re: Extrasolar Habitable Planets

The Planet That Shouldn’t Exist
https://www.universetoday.com/160278/th … dnt-exist/

What makes this discovery unique is the mass of TOI-5205b is rather large for orbiting such a young and small red dwarf star, thus challenging previous understandings of planetary formation and evolution. This is because gas giant exoplanets have traditionally been observed orbiting older and larger M dwarf stars.

Astronomers Suspected There Should Be a Planet Here, and Then They Took a Picture of it
https://www.universetoday.com/160247/as … ure-of-it/

The AF Leporis system shares similar features to our Solar System. As an F-type main-sequence star, AF Leporis is roughly the same size, mass, and temperature as the Sun (a G-type main-sequence star). In addition, the planet orbits its parent star at a distance similar to that between Saturn and the Sun, and the system has a debris belt with similar characteristics as the Kuiper Belt. However, the star and its system are quite young (~24 million years), which means that future studies could provide new insight into how the Solar System formed.

Last edited by Mars_B4_Moon (2023-03-09 05:09:46)

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#94 2023-03-06 10:09:13

Void
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Posts: 7,285

Re: Extrasolar Habitable Planets

I ran into this a day or two ago: https://www.msn.com/en-us/news/technolo … a2dd&ei=40

https://en.wikipedia.org/wiki/K2-18b
Quote:

K2-18b

K2-18b, also known as EPIC 201912552 b, is an exoplanet orbiting the red dwarf K2-18, located 124 light-years (38 pc) away from Earth.[4][5] The planet, initially discovered with the Kepler space telescope, is about eight times the mass of Earth, and is thus classified as a super Earth or a Mini-Neptune, and, as well, may be considered a hycean planet.[6] It has a 33-day orbit within the star's habitable zone.

In September 2019, two independent research studies, combining data from the Kepler space telescope, the Spitzer Space Telescope, and the Hubble Space Telescope, concluded that there are significant amounts of water vapor in its atmosphere, a first for an exoplanet in the habitable zone.[7][8][9]

K2-18 is a red dwarf: https://en.wikipedia.org/wiki/K2-18

So, how this could be important is that the planet apparently has an atmosphere, and is around a red dwarf.  It is either a "Super Earth" or a "Mini, or Sub-Neptune.  Of 8 x Earth?

Of the astrosphere is strongly greenhouse or very dense, the planet may be too hot for life, I would imagine.

But that leads to an interesting potential that a star with an aggressive solar wind might "Age" such a planet more rapidly than ours has aged Mercury, Venus, Earth, and Mars.

That is as atmosphere might be stripped away, such a planet might move from being a Sub-Neptune to a Hycean, to a Super-Earth, with a possible Nitrogen dominated atmosphere.

That would be nice, but I have to wonder if an Earth-like method would exist to sequester CO2?   Maybe not.

But the main point is a planet can retain an atmosphere on a planet orbiting a Red Dwarf Star.

Done.

Last edited by Void (2023-03-06 10:27:16)


Done.

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#95 2023-03-09 05:07:41

Mars_B4_Moon
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Re: Extrasolar Habitable Planets

Distant star TOI-700 has two potentially habitable planets

https://www.spacedaily.com/reports/Dist … s_999.html

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#96 2023-03-09 17:07:36

Mars_B4_Moon
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Re: Extrasolar Habitable Planets

ALMA images of the planet-forming disc around the star V883 Orionis

https://www.eso.org/public/images/eso2302b/

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#97 2023-03-13 21:13:44

Void
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Re: Extrasolar Habitable Planets

I felt it was worthwhile stopping by to drop this material off:

Habitable Planets Near Red Dwarfs, Fraser Cain
https://www.patreon.com/posts/habitable-near-79989561
https://www.bing.com/videos/search?q=Ha … M%3DHDRSC3

Where the above articles suggest that Red Dwarfs have enough shorter wavelengths to power Cyanobacteria, I am also going to suppose that it might be that over long periods of time life might find a way to work with far Infrared.

Just a possibility: https://www.science.org/content/article … ible-light

But also, for Red Dwarfs with radiation flares, I might expect Radiolysis to produce chemicals to power life.

And as these worlds, if they have a atmosphere may have strong winds and so also waves.  I might expect life feeding on movements.  Piezoelectric life, maybe.

The first two do exist on Earth.  Maybe Piezoelectric life does or did, but I expect that if it was at a disadvantage to other life, they may have become extinct.

That is what I think about it.

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Last edited by Void (2023-03-13 21:25:56)


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#98 2023-03-18 08:45:28

Mars_B4_Moon
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Re: Extrasolar Habitable Planets

Terminator zones on distant planets could harbor life

https://www.spacedaily.com/reports/Term … e_999.html

The terminator is the dividing line between the day and night sides of the planet. Terminator zones could exist in that "just right" temperature zone between too hot and too cold.

"You want a planet that's in the sweet spot of just the right temperature for having liquid water," said Lobo, because liquid water, as far as scientists know, is an essential ingredient for life.

On the dark sides of terminator planets, perpetual night would yield plummeting temperatures that could cause any water to be frozen in ice. The side of the planet always facing its star could be too hot for water to remain in the open for long.

"This is a planet where the dayside can be scorching hot, well beyond habitability, and the night side is going to be freezing, potentially covered in ice. You could have large glaciers on the night side," Lobo said.

Lobo, alongside Aomawa Shields, UCI associate professor of physics and astronomy, modeled the climate of terminator planets using software typically used to model our own planet's climate, but with a few adjustments, including slowing down planetary rotation.

It's believed to be the first time astronomers have been able to show that such planets can sustain habitable climates confined to this terminator region. Historically, researchers have mostly studied ocean-covered exoplanets in their search for candidates for habitability. But now that Lobo and her team have shown that terminator planets are also viable refuges for life, it increases the options life-hunting astronomers have to choose from.

"We are trying to draw attention to more water-limited planets, which despite not having widespread oceans, could have lakes or other smaller bodies of liquid water, and these climates could actually be very promising," Lobo said.

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#99 2023-03-18 20:27:48

Void
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Posts: 7,285

Re: Extrasolar Habitable Planets

Isaac Arthur has a lot of good analysis about such planets: https://www.bing.com/videos/search?q=Is … M%3DHDRSC4

I am going to look at it again and then comment.

He does seem to indicate that planets with atmospheres and oceans may not often tidally lock.

He also mentions that there are several ways tidal locked planets could wobble.  So, very likely the terminator would have sunlight variations, even the sun rising and setting on the horizon.

I have thought about our four terrestrials transferred to a red dwarf.  Of course they would have evolved differently then, but ignoring that and also ignoring the stripping of atmosphere, and allowing for the same heating levels, if tidal locked, I think.............

Mercury very hot on the sun side, and lots of ices and even possibly a ice covered ocean on the dark side.

Venus, I have wondered if the CO2 would condense out on the dark side.  The Nitrogen atmosphere might keep itself from freezing out on the dark side.  But I do wonder if there would be much water for the twilight zone.

Earth, I guess I sort of expect to see Tibet pointed at the star.  Even though in constant sunlight at the altitude it is perhaps it would be cool enough for water.  The Pacific would be in the dark and likely ice covered, but perhaps still liquid deep down.  The Terminator/Twilight zone would perhaps cross the America's, Japan, Australia, Antarctica.

Mars? Well the sun side would be warm, but the dark side would be very cold.  I guess all the CO2 and water might end up as ice on the dark side.

Still it might be useful to spacefaring entities.

Done.

Last edited by Void (2023-03-18 21:07:12)


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#100 2023-03-19 13:54:14

Mars_B4_Moon
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Registered: 2006-03-23
Posts: 9,761

Re: Extrasolar Habitable Planets

Thanks for the Isaac Arthur link Void,
I have enjoyed his videos before he does a good mix of speculation and science

Some other news commentary

'Searching for life and grappling with uncertainty'
https://thespacereview.com/article/4547/1

5312 confirmed Exoplanets
https://exoplanets.nasa.gov/

Systems 3,981

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