Exoplanet Stats

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5,500 exoplanets is today's count!

Here is the Kopparapu, et. al., HZ result, which is a more complex model that uses atmospheric qualifications for a HZ. Their model also uses a broader planet size range.

If we compare the following to the other methods (prior post) that restrict the probable habitable sizes to 0.5 to 1.8x Earth, then there are only three exos on this list that qualify (#28, 32, 33).

View: https://imgur.com/pAnS58v
 
Ug. Looks like I'm either doing something wrong with Imgur links or they are.
Both this and the next post show a run where the HZ is fudged by 10% in both directions. There are "optimistic" extensions of the HZ used that are far greater to cover a number of possibilities.

Let me try Postimages work....

Screenshot-2023-11-29-161500.png
 
An update is overdue, I suppose.

There are now many new features and tweaks.
1) A paper provides a formula to determine how an exo will see increasing luminosity for increasing eccentricity, but with a cutoff of around 0.5 ecc. as such a fluctuation seems highly unfavorable for habitability, IMO. This is now included.

2) The Equilibrium Temp. formula was found to always have the same results as what I call the Temp. Method (simple luminosity equation for HZi and HZo). But, the Eq. Temp. method bumps the HZinner to 1.15x the TM (Temp Method) and 0.42x the TM for the HZouter. IOW, it is a broader HZ (Habitable Zone) than the TM method.

3) Given #2, the program allows the User to have their own luminosity change factors. I have used 1.15 and 0.42. This broader zone is more than suggested by the Kopparapu, et. al., method incorporating atmospheric adjustments.

4) However, both the normal Temp. Meth. result and the User Luminosity adjustment results are shown together (e.g. "78% / 110%). The first value (78%) is how deep the orbital radius is within the HZ, where 50% is in the middle. The second value (110%) reveals that it is 10% beyond the HZo using the TM (Temp. Method).

5) As just stated, the User adjusts luminosity, not distance. It is luminosity that best determines our current understand of HZs for exoplanets so far.

6) The Classical Method, which uses numerous variables like mag., stellar class, temp. and radius, distance, has fewer results and, given the weaker accuracy of these, more trouble than it's worth, IMO. This may change as the data improves, perhaps.

7) The entire list is sorted by their relative distance from the star by converting their actual orbits to what they would be if they were orbiting the Sun. This is the Solar Equivalent Radius result.

8) Having #7 allows us to see the exoplanets progress in temperature (luminosity) zones where the more red colors represent the hotter zones and the blue and violet highlights show them as being in colder regions, but still within the HZ. The bright green represents the TM range of values.

There's more but "nuff said.", as Tyrus might say.

 
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Trappist system looks like the one to beat.
I'm doubtful any M-class planet will prove favorable over exos in any other class stellar system, assuming the same solar equivalent orbit. But, ignoring that, there are a couple of others that are near the middle of the HZ and are almost 10x farther from their likely active stellar host.

I think Kepler-62 f looks well placed. It may be a little in the cooler side of the HZ, but it has a 1.38 Re, so it likely has a healthy atmosphere to make up the difference. It's also farther away from the host, about that of Venus.
 
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Where is K2-18 b? The subject of a variety of reports indicating JWST may have found life on it.
K2-18 b was outside the User's exo size limits, which was 2.0 radii.

So, bumping this to 2.5R....



But, I'm not optimistic for any planet that orbits so close to its host, especially given that more and more we learn that M-class stars are found to be tantrum prone. Perhaps I've been around too many small (and fisty) dogs. :)
 
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In this last run, there are 127 HZ exoplanets with unknown radii. I could check, but I'd bet up to about half of these have known masses.

I made a small effort to calculate the range of density for those with known values in hopes I could use their density range to calculate these unknown radii, but the density variation was up to two orders! Perhaps another could figure this out. It could potentially give us a nice bump to our number of ideal HZ exo list.
 
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