Potentially Habitable Exoplanets

[Green Baron]

To support the modeling, a massive flare from Proxima Centauri was detected:

https://arxiv.org/abs/1802.08257

 

[Spaceception]

Kepler 1652 b has been added to the catalog, it seems when it was first announced, it was 1.6 x the radius of Earth. According to the catalog, however, it seems to be smaller at 1.1 x the radius of Earth.

Other values; (4.0 - 1.3 - 0.6) possible masses; 0.65 stellar flux; 229 K Eq temperature (Same as TRAPPIST 1 e); ~38 day orbit; and ESI of 0.85. It sits 822 light years away around a Red dwarf.

The count is now at 55.

http://phl.upr.edu/projects/habitable-exoplanets-catalog

Old data (There aren't any recent, up to date articles afaik); https://exoplanets.nasa.gov/newworldsatlas/6072/kepler-1652-b/

 

EDIT: Nearly missed this one!

So there were actually TWO planets added today. And here we gooo;

HD 283869 b* is a super-terran world. It's about 2 times the radius of Earth, and has a possible mass of (59.2 - 9.5 - 3.7) more than Earth. It has a 1.15 stellar flux; an Eq temperature of 264 K; a 106 day orbit; and an ESI of 0.77. It sits 155 light years from Earth

 

(* means it's unconfirmed)

Edited July 2, 2018 by Spaceception

[insert_name]

https://www.sciencealert.com/we-have-more-tantalising-evidence-that-two-earth-like-exoplanets-have-stable-climates-and-seasons-just-like-us

[Spaceception]

[EDIT] Turns out according to an article posted by @ProtoJeb21, the Equilibrium temperature of this world is 440 Kelvin, not nearly low enough to be potentially habitable. Sorry, false alarm 

Spoiler

Vulcan has been found!! 

 

Wait... what do you mean it's over 8 times the mass of Earth?
And it orbits in 42 days??

Aww, we were so close

 

Anyway, 40 Eridani Ab has been discovered recently, it's almost 8.5x the Mass of Earth, and is probably A: A water world B: A desert world C: A super-Venus. Or D: A Gas dwarf.

Still an awesome discovery though, the planet orbits every ~42 days, and is on the inner edge of the habitable zone, so it's a bit iffy. And there hasn't been enough time to add it to the list, but more massive planets have been added in the past. So in due time, and I'll update with values like stellar flux, possible radius, ESI, etc What are your thoughts?

http://www.sci-news.com/astronomy/hd-26965b-super-earth-06250.html

https://arxiv.org/pdf/1807.07098.pdf

 

 

Edited September 18, 2018 by Spaceception

[KG3]

16 minutes ago, Spaceception said:

 So in due time, and I'll update with values like stellar flux, possible radius, ESI, etc What are your thoughts?

 

What is stellar flux?  I'm assuming it's how variable the output of the star is.

[Spaceception]

26 minutes ago, KG3 said:

What is stellar flux?  I'm assuming it's how variable the output of the star is.

How much light the planet receives compared to Earth. For example; GJ 3323 b is a planet orbiting a red dwarf star around 17 light years away. it gets around 1.21x more light than Earth, or ~21% more

 

Because of this, it has a higher equilibrium temperature than Earth (Basically Earth's temperature with the same Albedo, and no atmosphere). For Earth it's 255 Kelvin (-18.15 Celsius). For GJ 3323 b it's 264 Kelvin (-9.15 Celsius).

Edited September 15, 2018 by Spaceception

[KG3]

46 minutes ago, Spaceception said:

How much light the planet receives compared to Earth. For example; GJ 3323 b is a planet orbiting a red dwarf star around 17 light years away. it gets around 1.21x more light than Earth, or ~21% more

 

So It's not about the output of the star, it's about how much light the planet receives.   

So you would say that GJ 3323 has a stellar flux of 1.21, or 21%?

[Spaceception]

12 minutes ago, KG3 said:

So It's not about the output of the star, it's about how much light the planet receives.   

So you would say that GJ 3323 has a stellar flux of 1.21, or 21%?

Yes.

1.21. Or 21% more ( 121%) to be more simple.

Edited September 15, 2018 by Spaceception

[Scotius]

Ouch. Heavy world. Mr. Spock would look more like a bunker than an elf LOL

[Spaceception]

See edit for a bit more detail, but 40 Eridani Ab isn't habitable. Stupid clickbait articles

[ProtoJeb21]

On 9/15/2018 at 8:54 AM, Spaceception said:

How much light the planet receives compared to Earth. For example; GJ 3323 b is a planet orbiting a red dwarf star around 17 light years away. it gets around 1.21x more light than Earth, or ~21% more

 

Because of this, it has a higher equilibrium temperature than Earth (Basically Earth's temperature with the same Albedo, and no atmosphere). For Earth it's 255 Kelvin (-18.15 Celsius). For GJ 3323 b it's 264 Kelvin (-9.15 Celsius).

Sorry to say this, but GJ 3323b is not habitable. The PHL catalog has some inaccurate parameters for some of the listed planets, mainly stellar flux. One example is K2-72e — its flux of 1.4 on the catalog is too high; it’s actually around 1.1. For GJ 3323b, it’s the opposite: the planet’s actual stellar flux is twice that of Earth’s instead of just 21% higher, meaning that it is likely a Venus analogue. The best case scenario for the habitability of the GJ 3323 system is that the second planet has a subsurface ocean underneath an ice shell, which seems pretty likely given its orbit. 

1 hour ago, Spaceception said:

See edit for a bit more detail, but 40 Eridani Ab isn't habitable. Stupid clickbait articles

It also won’t be named Vulcan, no matter how much you want it to be. 

 

As I mentioned in another post, 40 Eridani A could still host other Super-Earths, maybe one in the habitable zone. For optimal temperatures, it would have to orbit between 170 and 220 days, but it could still be warm enough up to 280 days depending on its atmosphere. Planets closer to 40 Eri then not-Vulcan could exist as well.

[Spaceception]

55 minutes ago, ProtoJeb21 said:

Sorry to say this, but GJ 3323b is not habitable. The PHL catalog has some inaccurate parameters for some of the listed planets, mainly stellar flux. One example is K2-72e — its flux of 1.4 on the catalog is too high; it’s actually around 1.1. For GJ 3323b, it’s the opposite: the planet’s actual stellar flux is twice that of Earth’s instead of just 21% higher, meaning that it is likely a Venus analogue. The best case scenario for the habitability of the GJ 3323 system is that the second planet has a subsurface ocean underneath an ice shell, which seems pretty likely given its orbit. 

It also won’t be named Vulcan, no matter how much you want it to be.

1

Huh, didn't know that. That's unfortunate. I liked that planet.

I honestly thought they got new measurements for the K2-72 star, and that's why the stellar flux for the planet changed.

I know, it was just a reference.

[ProtoJeb21]

22 minutes ago, Spaceception said:

Huh, didn't know that. That's unfortunate. I liked that planet.

I honestly thought they got new measurements for the K2-72 star, and that's why the stellar flux for the planet changed.

I know, it was just a reference.

At least GJ 3323c is completely unique. There is no other planet we know of with this mass, orbit, and temperature. 

I used the new K2-72 measurements to calculate the stellar flux of K2-72e. I don’t know why it’s so high on the PHL catalog. 

[Spaceception]

1 minute ago, ProtoJeb21 said:

At least GJ 3323c is completely unique. There is no other planet we know of with this mass, orbit, and temperature. 

I used the new K2-72 measurements to calculate the stellar flux of K2-72e. I don’t know why it’s so high on the PHL catalog. 

Ah. When did you do that? Could they just not have had the time to update? Maybe you could shoot them an email or something

[ProtoJeb21]

There are two major updates on two different potentially habitable systems to talk about: LHS 1140 and K2-18.

First off, the K2-18 system has been re-analyzed again due to the questionable nature of K2-18c. A second study concluded that this planet was a false positive and just an artifact from stellar activity. Howeve, this study did a more careful analysis and found that it is a legitimate planet. It turns out the former accidentally associated K2-18c with the star’s typical activity, when the two signals are shown to be separate after a longer analysis.

Not only is K2-18c re-confirmed in this study, but it also kinda kills any hope for life on K2-18b. Why? Because of the Gaia Data Release 2. According to Gaia data, K2-18 is slightly larger than initially expected, which puts K2-18b at 2.711 Re and 8.63 Me. This gives it a density of just 2.4 g/cm^3, too low for a water-rock planet like previous estimates showed. However, K2-18c is actually less massive than previously thought, with a minimum mass of 5.6 Me. It could be primarily rocky with a thick atmosphere and/or a water envelope. 

The full paper can be read here: https://arxiv.org/pdf/1810.04731.pdf

 

The other system with a major update is LHS 1140. A second, much smaller planet was confirmed, with less than twice the mass of Earth and a little over a quarter larger in radius, giving it a composition similar to TRAPPIST-1b. The paper that it was reported in claims that LHS 1140c has an “Earth-like composition”, which is absolutely not the case — its density implies a rather thin but still significant layer of water. This could be in the form of a very thick, Super-Venus atmosphere, not unlike that of TRAPPIST-1b. However, I have doubts about the radius of LHS 1140c, because it was calculated using new Gaia DR2 parameters for LHS 1140. This also makes LHS 1140b larger and less dense than initially thought, but that isn’t a bad thing. With 7 times the mass of Earth and 1.73 times Earth’s radius, LHS 1140b is, composition wise, a massively scaled-up version of Earth. This makes it by far the largest rocky habitable zone planet yet found, and also puts it in the rare class of rocky planets with radii above the 1.6 Re transition boundary. 

LHS 1140 is a pretty awesome system with a Super-Venus and a Super-Super-Earth, but it may be ever more complex. The people behind the study that confirmed LHS 1140c noted that it and LHS 1140b have just about the same relative inclination to one another. While at first this may not seem like much, it turns out that this phenomena is only seen with compact multi-planet systems like TRAPPIST-1 and Kepler-186. The authors concluded that LHS 1140 is likely to have more planets that have yet to be detected. While a ~90 day signal was reported by another team a few months ago, this is likely not the only other planet in the system; others likely exist between 1140c and 1140b. Maybe one of them could be in the habitable zone as well!

The LHS 1140 paper can be read here: https://arxiv.org/abs/1808.00485

Edited October 14, 2018 by ProtoJeb21

[ProtoJeb21]

I forgot to mention this earlier: K2-18b is very similar in mass, radius, and density to GJ 1214b, although it has a greater amount of heavier materials and a lower temperature. 

[DAL59]

On 9/15/2018 at 8:07 AM, Spaceception said:

Vulcan

 

On 9/15/2018 at 8:07 AM, Spaceception said:

42

hmmm

[Diche Bach]

Ah looks like I need to get in on this.

Have you guys eliminated Proxima b or are you among the "hope beyond hope" crowd?

ADDIT: Imagine the drama in this thread in 10 or 20 years when they finally get James Webb out there and peering at the atmospheres . . .

 

Edited October 15, 2018 by Diche Bach

[Spaceception]

10 hours ago, Diche Bach said:

Have you guys eliminated Proxima b or are you among the "hope beyond hope" crowd?

1

Iffy. The radiation situation doesn't look good. And since there doesn't seem to be any transits, we can't get a better look to see what's going on.
And I'm assuming this is related to the other questions you've been posting.   So assuming you really want to colonize it, it's nothing we couldn't get around with technology.
The tech proposed for potentially giving Mars a magnetic field could also be boosted for Proxima b. Then it's just a matter of giving it an atmosphere, and water over time, using a similar process that we'd do for Mars. Except, we may want large orbital mirrors to light up the dark side, and eventually work something out to give it a faux day/night cycle. Considering it's larger than Earth, and receives more light than Mars, it's a better terraforming candidate. Strictly speaking. We just have to, y'know, get there.

[Diche Bach]

Well, apparently it MIGHT have that 3/2 orbital synchrony and if it had a very high saline content oceans, then that combined with the 3/2 (264 Earth-hour long "day" and same length "night" and no appreciable seasons . . . don't think an axial tilt is viable with the 3/2?) means that some modeling suggests it could be "tropical" along the equator!

ADDIT: also! Gotta have a VERY good magnetosphere which has been functioning reliably for its whole ~4 billion year lifetime protecting the planet from Proxima's radioactive tantrums! 

Edited October 29, 2018 by Diche Bach

[Diche Bach]

Lotta "ifs" but I suppose there is some slim chance Proxima isn't a scorched, airless rock. I suppose the whole color scheme for flora would be totally different given Proxima is shifted more to the infrared end of the spectrum? Seem to recall someone saying that an analog of chlorphyll in that context would need to be more toward the black end of the spectrum in order to be optimized the way our green chlorphyll is optimized for Sol.

[Spaceception]

21 minutes ago, Diche Bach said:

Lotta "ifs" but I suppose there is some slim chance Proxima isn't a scorched, airless rock. I suppose the whole color scheme for flora would be totally different given Proxima is shifted more to the infrared end of the spectrum? Seem to recall someone saying that an analog of chlorphyll in that context would need to be more toward the black end of the spectrum in order to be optimized the way our green chlorphyll is optimized for Sol.

Yep, or just anything dark. Dark red, dark purple, black, something along those lines, it would depend.

[Spaceception]

Welcome back Tau Ceti e, now confirmed as the closest potentially habitable world around a G type star.

Unfortunately, it seems Ross 128 is no longer potentially habitable from possibly being too hot. And the site is also going through some changes so more may be added/removed with new data. The previous count was 55, now it'll be 48 once Tau Ceti e is re-added.

The masses of e and f are still the same, so further observations will be needed to confirm their masses.

 

[ProtoJeb21]

19 hours ago, Spaceception said:

Welcome back Tau Ceti e, now confirmed as the closest potentially habitable world around a G type star.

Unfortunately, it seems Ross 128 is no longer potentially habitable from possibly being too hot. And the site is also going through some changes so more may be added/removed with new data. The previous count was 55, now it'll be 48 once Tau Ceti e is re-added.

The masses of e and f are still the same, so further observations will be needed to confirm their masses.

 

I hope we get more precise data on the Tau Ceti system soon, especially on the masses and orbital eccentricities of the planets. I’m pretty confident they’re all rocky because of the host star’s low metallicity (less metals = less likely for gas planets to form), even if Tau Ceti e and f end up being around 7-8 Earth masses as suspected, but better eccentricity estimates will be good to determine whether or not Tau Ceti e strays too close to be habitable. 

The PHL has also, after all this time, FINALLY updated K2-72e with its correct stellar flux, making it the most Earth-like planet ever found so far (until K2-72f gets confirmed). I hope they update the insolations and other parameters for the planets that really need it, like Luyten b (the PHL’s stellar flux estimate is too high), the TRAPPIST-1 planets (their radii and masses are outdated), and GJ 3323b (it’s flux estimate is too low).

[Spaceception]

16 minutes ago, ProtoJeb21 said:

I hope we get more precise data on the Tau Ceti system soon, especially on the masses and orbital eccentricities of the planets. I’m pretty confident they’re all rocky because of the host star’s low metallicity (less metals = less likely for gas planets to form), even if Tau Ceti e and f end up being around 7-8 Earth masses as suspected, but better eccentricity estimates will be good to determine whether or not Tau Ceti e strays too close to be habitable. 

The PHL has also, after all this time, FINALLY updated K2-72e with its correct stellar flux, making it the most Earth-like planet ever found so far (until K2-72f gets confirmed). I hope they update the insolations and other parameters for the planets that really need it, like Luyten b (the PHL’s stellar flux estimate is too high), the TRAPPIST-1 planets (their radii and masses are outdated), and GJ 3323b (it’s flux estimate is too low).

Yeah, has anyone looked for transits? That would be good too.

Are you going to email them about it? Or do you think they're just getting to it?