The hunt is on for exomoons around alien planets and scientists may have just found one

Nov 13, 2020
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Time for another tantalizing glimpse of what alien solar systems might look like.

The hunt is on for exomoons around alien planets and scientists may have just found one : Read more
I looked at the up-to-date version of The Extrasolar Encyclopedia main database at http://exoplanet.eu/catalog/ and could not find any entry for Kepler 1708 b. Has that planet indeed been confirmed and if so why isn't the parent planet of this second proposed exomoon listed in The Extrasolar Encyclopedia? Alternatively, if Kepler 1708 b is listed in the Extrasolar Encyclopedia is listed with some other name or designation such KIC or KOI something or other, what is that catalog name corresponding to the parent planet Kepler 1708 b associated with this second exomoon candidate of a planet around Kepler 1708 b. Also what are some of the characteristics of the parent planet Kepler 1708 b such as how far from Earth this system is, what type of parent star is in this system, how far from its parent star the planet Kepler 1708 b is, how elliptical the orbit of Kepler 1708 b is etc.
 
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If we are going to find signs of life i think the Exo's will be the places.
So much going for them, math good for stability of climate and protection from radiation/flares from a wide set of star types.

Earth/moon systems are sure to be a very odd rare setup for life.
 
I looked at the up-to-date version of The Extrasolar Encyclopedia main database at http://exoplanet.eu/catalog/ and could not find any entry for Kepler 1708 b. Has that planet indeed been confirmed and if so why isn't the parent planet of this second proposed exomoon listed in The Extrasolar Encyclopedia? Alternatively, if Kepler 1708 b is listed in the Extrasolar Encyclopedia is listed with some other name or designation such KIC or KOI something or other, what is that catalog name corresponding to the parent planet Kepler 1708 b associated with this second exomoon candidate of a planet around Kepler 1708 b. Also what are some of the characteristics of the parent planet Kepler 1708 b such as how far from Earth this system is, what type of parent star is in this system, how far from its parent star the planet Kepler 1708 b is, how elliptical the orbit of Kepler 1708 b is etc.

Okay, the .eu site is updated now with 1708 b and 1708 b-i with properties shown. http://exoplanet.eu/catalog/kepler-1708_b/, and http://exoplanet.eu/catalog/kepler-1708_b-i/

The NASA site is updated too, https://exoplanetarchive.ipac.caltech.edu/overview/Kepler-1708 b#planet_Kepler-1708-b_collapsible

I use both sites in my MS ACCESS DB. These two sites update frequently.
 
Nov 13, 2020
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Okay, the .eu site is updated now with 1708 b and 1708 b-i with properties shown. http://exoplanet.eu/catalog/kepler-1708_b/, and http://exoplanet.eu/catalog/kepler-1708_b-i/

The NASA site is updated too, https://exoplanetarchive.ipac.caltech.edu/overview/Kepler-1708 b#planet_Kepler-1708-b_collapsible

I use both sites in my MS ACCESS DB. These two sites update frequently.
Thank you. This morning, I checked the Extrasolar Encyclopedia and their update of Kepler 1708 b and its moon Kepler 1708 b i so I'm all caught up with the information now in this regard.
 
Here is an update on the search for exomoons.

Large exomoons unlikely around Kepler-1625 b and Kepler-1708 b, astronomers say

Ref - https://www.nature.com/articles/s41550-023-02148-w, 07-Dec-2023. My note, the exoplanet.eu site shows this exomoon as confirmed, https://exoplanet.eu/catalog/exomoon_kepler_1708_b_i--8059/ At least Kepler-1708 b planet status is confirmed.

Something I note from the phys.org report "...The researchers also used their algorithm to predict the types of actual exomoons that could be clearly detectable in light curves space missions like Kepler. According to their analysis, only particularly large moons orbiting their planet in a wide orbit are detectable using current technology. Compared to the familiar moons of our solar system, they would all be oddballs: at least twice the size of Ganymede, the largest moon in the solar system and therefore almost as big as Earth. "The first exomoons that will be discovered in future observations, such as from the PLATO mission, will certainly be very unusual and therefore exciting to explore," says Heller.”

I note no confirmed exomoons documented with certainty among the exoplanets presently. No giant impact model exomoons shown either. The only planet in our solar system said to have a moon created via a giant impact is earth and so far, no other analog moons like this documented in nature for their origin.
 
Perhaps the monster scopes coming our way will have enough capability to find some.

The best chances for them are likely to be found around larger planets that formed outside the frost zone, like Jupiter and Saturn.

Another important point is the rotation period of the planet compared to the orbital period of its moons. A slow rotating planet will cause the moons to auger in. But. if the moons have orbital resonance, then they might survive.
 
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Helio, ref your post #8. Indeed, finding exomoons looks very challenging. I did a SQL query review of these two exoplanets sites this morning (using the updated confirmed lists).


The exoplanet.eu site shows 277 exoplanets where the radius is 1.1 or smaller earth size. The majority of the exoplanets are large compared to earth size, something I think is not commonly pointed out. The NASA exoplanet archive site shows 272 using same radii query size. If there are any exomoons that are analogs to what we see here in our solar system, this remains to be confirmed and published.
 
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Helio, ref your post #8. Indeed, finding exomoons looks very challenging. I did a SQL query review of these two exoplanets sites this morning (using the updated confirmed lists).
Indeed. An exomoon the size of our Moon at only 2 lightyears has the same apparent size as that of a golf ball (1.68”) on the Moon.



The exoplanet.eu site shows 277 exoplanets where the radius is 1.1 or smaller earth size. The majority of the exoplanets are large compared to earth size, something I think is not commonly pointed out. The NASA exoplanet archive site shows 272 using same radii query size. If there are any exomoons that are analogs to what we see here in our solar system, this remains to be confirmed and published.
If you include those in likely HZs, then there are only 15 (per the Exoplanet Stats thread), though the size range is from 0.5 to 1.8R— a range some scientists prefer to use for the more probable life-favoring sizes. There is still only one of these 15, Kepler 452b, that orbits a G-type star.
 
There are about 150 exos that are both large enough and orbit far enough to give favorability in having exo moons. I would bet that most if not all will eventually be shown to have exomoons. There are over 240 moons around Jupiter and Saturn combined.
 
Indeed. An exomoon the size of our Moon at only 2 lightyears has the same apparent size as that of a golf ball (1.68”) on the Moon.



If you include those in likely HZs, then there are only 15 (per the Exoplanet Stats thread), though the size range is from 0.5 to 1.8R— a range some scientists prefer to use for the more probable life-favoring sizes. There is still only one of these 15, Kepler 452b, that orbits a G-type star.
FYI, as I calculate an angular size of 1.68" on the surface of the Moon (1.68 arcsecond), I get 3.1309 km diameter using a distance of 384401 km from my telescope. My telescopes at 200x or more will resolve lunar craters on the surface that small. If this math shows anything about imaging and seeing exomoons that are analogs to what we see in our solar system (small sizes), the task of confirming such exomoons among the exoplanets remains. Using my telescopes, I will not be able to see them like I can at Jupiter or Saturn :)
 
FYI, 1 arcsecond angular size resolved in a good telescope for an object 10 pc distance, the diameter is 10 AU or about the distance between the Sun and Saturn. Resolving and imaging exomoons will be tough work unless other methods are used to measure exomoons.
 
Given the observations from our own solar system, where most planets have moons of some sort, it seems that exoplanets would also be very likely to have some sorts of moons.

In our own system, we are even finding asteroids with smaller asteroids orbiting them, and one (so far) of those smaller orbiting asteroids itself seems to be made of 2 pieces actually touching each other.

So, I think the only real question is whether we will find planets with moons that have some beneficial effects for the probability of life on the planet they orbit, or maybe life on the moon orbiting the exoplanet.

Considering the necessary relationships for that, I don't think we could yet detect that type of planet/moon system. But, I expect we will whenever we develop the ability to find them.

To me, the more intriguing question is whether we will find "double planets" that we see so often in fiction. Even double planets that are not likely to sustain life would be interesting. Can they really form and persist/survive long enough to have a significant population our there?
 
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FYI, the NASA archive site shows number of stars involved in exoplanets like binary or triple star systems or even four stars as well as number of planets found orbiting a star. https://exoplanetarchive.ipac.caltech.edu/index.html

5557 exoplanets are confirmed, I do not see any *double planets*. I do see 2366 confirmed exoplanets in solar systems ranging from 2 to 8 exoplanets, and multiple star systems, 502 exoplanets orbiting stars 2-4 in number. IMO, I prefer facts, not theories that remain unconfirmed in science. So far, there are no confirmed exomoons or exomoons that formed via a giant impact theory. The explanation for the origin of the Moon using the giant impact model stands unique presently, even in our solar system. This is a simple summary of what is presently known in nature using real natural world observations. I can think there is all kinds of interesting stuff out there somewhere, but the scientific method must show the interesting stuff is real in nature just like Galileo had to show there were indeed tiny lights moving around Jupiter that others could follow up and confirm too.
 

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