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What do you think about the super flare of the star Proxima Centauri?

Posted: 26 Oct 2018 09:21
by astroclu
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Moreover, most of those planets close to their stars are tidally locked, so one hemisphere is very hot and the other one is very cold and dark, so even it manages to keep an atmosphere with these flares, the weather at the transition would be pretty extreme. 

Do you think Tau Ceti e is inhabited?

Posted: 08 Feb 2019 17:21
by alfa015
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Hi!


Guys do you think Tau Ceti e is inhabited?

It was recently confirmed (https://twitter.com/i/web/status/1084742558041993216) and it is considered a potentially habitable exoplanet (http://phl.upr.edu/projects/habitable-exoplanets-catalog)

I just made a video about it, just in case someone is interested: https://www.youtube.com/watch?v=Lhfu3DXoOCA&list=PL3RiFKfZj3pv1ZqpFxuZinoGtUGEOankw

Do you think Tau Ceti e is inhabited?

Posted: 08 Feb 2019 17:51
by Stellarator
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Does this announcement warrant a whole new topic on the forum? I mean, why not post this in an already existing topic like Exoplanets news? Or Science & Astronomy news?

Do you think Tau Ceti e is inhabited?

Posted: 08 Feb 2019 23:13
by JackDole
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Or in Your SpaceEngine Videos.

Do you think Tau Ceti e is inhabited?

Posted: 09 Feb 2019 00:03
by Watsisname
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There are a lot of planets considered "potentially habitable", but these include planets that may be more similar to Mars or Venus than to Earth.  We'll be better able to conclude something about whether a planet may have life on it when we have spectroscopic measurements of their atmospheric compositions.

Do you think Tau Ceti e is inhabited?

Posted: 09 Feb 2019 10:02
by midtskogen
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And the "habitable zone" usually disregards the stability of the star.  Many stars have violent eruptions making life on the surface very unlikely.  Tau Ceti appears to be pretty stable, though.

Do you think Tau Ceti e is inhabited?

Posted: 09 Feb 2019 20:14
by Stellarator
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midtskogen wrote:
Source of the post Tau Ceti appears to be pretty stable, though.


It is also older the our sun. Studies have placed Tau Ceti to be anywhere between 5.8 to 10 billion years old (these great discrepancies are a result of differing studies using differing methods). However, that doesn't mean that the star wasn't violent in its past - perhaps enough to sterilize any planets orbiting it. In addition, it possess a dust and debris cloud starting at around 6 AU from Tau Ceti and extending out to 16 AU. This cloud is ten times as dense of Sol's Asteroid Belt, being more analogous to our Kuiper Belt. Unless there is an as of yet undetected gas-giant deflecting errant members of this cloud, impacts will be in high supply for the inner planets of Tau Ceti - including e.

As for e's habitability, this paper on planetary habitability casts some doubt on this idea (it is discussed on pg. 3-4), summarizing that planet e and probably planet f are super-massive Cytherian-type worlds due to the amount of radiation they receive from Tau Ceti in their current orbits. Of course, we cannot rule out Venus in our own solar-system having life in its clouds or deep underground, but it is generally thought of as a remote possibility.

Do you think Tau Ceti e is inhabited?

Posted: 09 Feb 2019 20:59
by Gnargenox
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I hear Tau Ceti f, a bit smaller and chilly, being on the edge of the HZ, has migrated inward and only been there 2 million years?

Do you think Tau Ceti e is inhabited?

Posted: 10 Feb 2019 00:47
by Stellarator
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Gnargenox:Source of the post has migrated inward and only been there 2 million years?


Yes, over the past billion years it has migrated from the outer regions into it's current orbit - which is still outside the HZ. Furthermore, it as of yet remains on the lower end of so-called sub-neptune exoplanets in terms of mass. Perhaps 'ice-shell' life like that astronomers think may exist in the subglacious oceans of Europa could exist under the icy surface of Tau Ceti f.

Such life seems to be as vogue nowadays in speculatory astrobiology as life on Mars was back in the 70s and 80s. I'm not saying that it's the wrong idea, I just find it a bit pathetic of the public media to latch onto this idea based on recent trends in academic thought.

BREAKING: New potentially habitable exoplanet found around Teegarden's star

Posted: 19 Jun 2019 05:58
by alfa015
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Astronomers have discovered a potentially habitable exoplanet around Teegarden's Star.

Teegarden is an old red dwarf star 12 light-years away in the Aries constellation.
 
The exoplanet found, called Teegarden b, has a minimum mass almost identical to Earth.
 
It orbits within the star's habitable zone.
 
And it has a 60% chance of having a temperate surface environment.
 
Surface temperature should be closer to 28°C assuming a similar terrestrial atmosphere.
 
Teegarden b is the exoplanet with the highest Earth Similarity Index discovered so far: 95%.
 
This means that it has the closest mass and insolation to terrestrial values.
 
Source: https://www.youtube.com/watch?v=eNGXerXGnjo

BREAKING: New potentially habitable exoplanet found around Teegarden's star

Posted: 20 Jun 2019 00:12
by Watsisname
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alfa015 wrote:
Source of the post The exoplanet found, called Teegarden b, has a minimum mass almost identical to Earth.


I hate to dim the excitement, but I think that this part is important to emphasize.  When detecting an exoplanet by radial velocity measurements, the strength of the signal (how much it tugs its host star along our line of sight) depends on the inclination of the orbit, which is unknown (unless the planet also transits).  So the mass is reported as a minimum possible value.  

If the true orbit is edge on, then the reported mass is the true mass.  But if it's closer to face on, then the true mass can be several times larger, because we only see a small portion of the star's induced wobble. It's statistically inevitable that some "potentially habitable planets" reported by radial velocity measurements are not planets at all, but brown dwarfs.

I think the excited announcements of potentially habitable exoplanets should be more limited to planets found by combination of both radial velocity and transit method, since then we get not only the true mass, but also the planets radius, and thus density and a good idea of its bulk composition. 

The other big unknown is its atmosphere.  This world could be much more like Venus than Earth, baked under a tremendous greenhouse atmosphere.  Hopefully with next generation telescopes we can get much better data on atmospheric compositions, and look for evidence that they are not only potentially habitable, but actually inhabited. :)

BREAKING: New potentially habitable exoplanet found around Teegarden's star

Posted: 20 Jun 2019 00:37
by JackDole
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Addons for the newly discovered planets (there are two planets!): viewtopic.php?f=3&t=301&start=30#p30056 and viewtopic.php?f=3&t=301&start=30#p30064

BREAKING: New potentially habitable exoplanet found around Teegarden's star

Posted: 20 Jun 2019 05:10
by Gnargenox
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What I thought was pretty cool was any Observer from Teearden could possibly detect Earth with the transit method, both Stars will be in perfect position in 25 years.

BREAKING: New potentially habitable exoplanet found around Teegarden's star

Posted: 26 Jun 2019 17:10
by A-L-E-X
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Will this planet be added to 0.990 automatically or should I add JD's version manually?

BREAKING: New potentially habitable exoplanet found around Teegarden's star

Posted: 26 Jun 2019 21:02
by JackDole
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A-L-E-X wrote:
Source of the post Will this planet be added to 0.990 automatically or should I add JD's version manually?


In the latest version of SE 0.990, the planets of Teegarden's Star are already included.
You do not need my version anymore.