Kepler exoplanets

[jonnydreads]

just out of interest does anyone know why there a seemingly large amount of Kepler exo planets all bunched up together in one area, they all pass from northwest to north between 6pm to 11pm tonight, I just wondered is that just coincidence that theres so many in one area or was it concentrating on one area in particular for efficiency reasons?

[Ags]

Kepler only looked at one small area of the sky ?

[jonnydreads]

wow, I'm blown away, how can there not be life everywhere!

[Ags]

The new planet hunter, TESS, is looking everywhere, so imagine how many planets it will find!

[Carbon Brush]

What I find amazing is that until 1993 or 94, the idea of exoplanets was just a possibility. Nothing had been observed.
When I say observed, I mean star motion observations to detect 'hot Jupiters'.

In twenty odd years we have thousands of planets identified or likely. We detect not just star wobble, but light dip.
There is even research on looking at the characteristics of the light dip to determine the presence and likely composition of an atmosphere.

Incredible.

[Davey-T]

It's now thought that pretty much every star has planets which means there are lot's more planets than the estimated 200 billion stars in the Milky Way, how many can support life as we know it is another thing completely.

Dave

[Ags]

We even have photographs of exoplanets and time lapses of them going around their star.

[Ags]

https://www.eso.org/public/videos/potw1846a/

https://www.google.com/amp/s/www.vox.com/platform/amp/2017/1/28/14412866/exoplanets-orbit-star-time-lapse

[SIDO]

It depends on how one classifies a planet, our solar system has about 400 bodies all large enough to be considered planets if one only looks at a limited data set to discribe a planet then large moons and dwarf planets are also lumped in and more of these bodies are yet to be found in orbit around our star. Most of the planets we are discovering around other stars are large or what we would classify as we do the 8 recognized planets circling our sun as with a stars brightness these larger exoplanets are the easiest to discover at great distances, In imagining how many planets are in the Milky Way it would depend on how these exoplanets are classified so as many as 200 billion x 400 exoplanets are possibly in the Milky Way...

 

Then if one considers there are trillions of galaxies in the known universe to date the # of possible exoplanets goes off the charts...

https://www.universetoday.com/30305/how-many-galaxies-in-the-universe/

[Ags]

Counting the planets in the solar system is just the classic problem of geography. When is a mountain a mountain, and when is it a hill? When is a stream a river, or when is an island a continent? It's not surprising that the British have a definition of "mountain" that implies that Britain has mountains, while in comparison I lived on a flat plain in South Africa at an altitude of 1700m (500m higher than the highest British "mountains") and never thought of myself as a mountaineer!

Realistically, a planet is a significant feature of our local geography, just like continents or oceans are. That means there are a manageable number of them - not 40 or 400, but around 10. We will always have a definition of planet that gives a number (in our solar system) of around 10. This is exactly why the definition of planet was adjusted by the IAU to exclude Pluto, to avoid the number of planets in our solar system getting too large. For similar reasons, Asteroids were reclassified as non-planets in Victorian times, because there were too many of them.

If humans were smarter and could easily memorize lists of hundreds, we would probably have a different definition of planet!

[SIDO]

57 minutes ago, Ags said:

Counting the planets in the solar system is just the classic problem of geography. When is a mountain a mountain, and when is it a hill? When is a stream a river, or when is an island a continent? It's not surprising that the British have a definition of "mountain" that implies that Britain has mountains, while in comparison I lived on a flat plain in South Africa at an altitude of 1700m (500m higher than the highest British "mountains") and never thought of myself as a mountaineer!

Realistically, a planet is a significant feature of our local geography, just like continents or oceans are. That means there are a manageable number of them - not 40 or 400, but around 10. We will always have a definition of planet that gives a number (in our solar system) of around 10. This is exactly why the definition of planet was adjusted by the IAU to exclude Pluto, to avoid the number of planets in our solar system getting too large. For similar reasons, Asteroids were reclassified as non-planets in Victorian times, because there were too many of them.

If humans were smarter and could easily memorize lists of hundreds, we would probably have a different definition of planet!

So then are planets in other systems also classified in this manner and how are exoplanets designated as to the geography of their systems?

I thought the video link I posted covered planetary bodies as well the IAU defined classifications this was meant generalize of course. But aren't all exoplanets indeed classified only as exoplanets so then comparing our system requires reducing our classifications to the exoplanet standard? 

 

[Whirlwind]

6 hours ago, SIDO said:

So then are planets in other systems also classified in this manner and how are exoplanets designated as to the geography of their systems?

I thought the video link I posted covered planetary bodies as well the IAU defined classifications this was meant generalize of course. But aren't all exoplanets indeed classified only as exoplanets so then comparing our system requires reducing our classifications to the exoplanet standard? 

 

The recent change in the definition is that the object had to be able to clear it's neighbourhood of objects and be the dominant object in it's orbital path.  Hence Pluto demoted because it did not dominate it's surroundings. Neptune passes by it's orbital path and if they ever interacted (and they probably will at some point) then Pluto would be scattered depending on the type of interaction.  The exoplanets we have currently found would generally all fall under this category as we don't really have the technology to find small planets around sun like stars.  A lot of focus (including TESS) is to look at cooler, smaller stars because to be in the habitable zone they have to be closer which makes a probability of a transit much more likely.  Because the planet is proportionally larger to a small star the transit depths are also easier to spot; the mass has more impact on the star and hence easier to determine the radial velocity etc.  All of these planets however are large enough to have cleared their orbital path.  

There is however one known minor planet identified with some surety.  It is around the White Dwarf WD1145+017.  Here there is a large asteroid that is disintegrating as it approached too close to the White Dwarf.  You can see the transits as this object pass in front of the White Dwarf (or strictly speaking you can see the dust cloud from it breaking up).  You can see them because the White Dwarf is so small (on the order of Earth sized).

[SIDO]

6 hours ago, Whirlwind said:

The recent change in the definition is that the object had to be able to clear it's neighbourhood of objects and be the dominant object in it's orbital path.  Hence Pluto demoted because it did not dominate it's surroundings. Neptune passes by it's orbital path and if they ever interacted (and they probably will at some point) then Pluto would be scattered depending on the type of interaction.  The exoplanets we have currently found would generally all fall under this category as we don't really have the technology to find small planets around sun like stars.  A lot of focus (including TESS) is to look at cooler, smaller stars because to be in the habitable zone they have to be closer which makes a probability of a transit much more likely.  Because the planet is proportionally larger to a small star the transit depths are also easier to spot; the mass has more impact on the star and hence easier to determine the radial velocity etc.  All of these planets however are large enough to have cleared their orbital path.  

There is however one known minor planet identified with some surety.  It is around the White Dwarf WD1145+017.  Here there is a large asteroid that is disintegrating as it approached too close to the White Dwarf.  You can see the transits as this object pass in front of the White Dwarf (or strictly speaking you can see the dust cloud from it breaking up).  You can see them because the White Dwarf is so small (on the order of Earth sized).

When replying you did not watch the video I posted or you would have known I posted most of this information already...that's perfectly ok though because some of that wich was contained in the video is now in print for others not willing to follow my posted link and since I only wished to share this info with the OP and others thanks for your help doing that. As long as we are on the same page that's the important thing.

I am researching WD1145,017 you called this a minor planet but shouldent it be an exoplanet by  primary definition and are you calling them minor and major exoplanets? I did enquire about exoplanet classification and you quoted me, just curious not trying to be problematic or the like ?

 

[SIDO]

Here are the new exoplanet classifications. 

These classifications are derived from planets in the Kepler Survey...

(<2 R_⊕) rocky planets, (2–4 R_⊕) water worlds, (4–10 R_⊕) transitional planets, and (>10 R_⊕

https://www.cfa.harvard.edu/news/su201837 

https://m.phys.org/news/2018-09-classification-scheme-exoplanet-sizes.html?

[Star101]

On 09/02/2019 at 17:40, jonnydreads said:

wow, I'm blown away, how can there not be life everywhere!

Maybe they do have single cell life/slime. As that is what was on earth until about 600 million years ago....That's 3.2 billion years of slime beforehand any sort of animal arrived. So, it took life 3.2 Billion years to produce animals. And as far as we know, there are no multi-cellular creatures anywhere else in the universe.

[SIDO]

If I should ever be lucky enough to discover an exoplanet myself I've decided its designation and I will name it "Pulling Teeth" ?

[jonnydreads]

5 hours ago, Star101 said:

Maybe they do have single cell life/slime. As that is what was on earth until about 600 million years ago....That's 3.2 billion years of slime beforehand any sort of animal arrived. So, it took life 3.2 Billion years to produce animals. And as far as we know, there are no multi-cellular creatures anywhere else in the universe.

if the universe is expanding then really there also could be life that is also billions of years ahead of us evolutionary speaking.. if the universe is 14 billion years old there could be life out there 8 or 9 billions years in front! ??

[Star101]

1 hour ago, jonnydreads said:

if the universe is expanding then really there also could be life that is also billions of years ahead of us evolutionary speaking.. if the universe is 14 billion years old there could be life out there 8 or 9 billions years in front! ??

Maybe.

If their star lives long enough!, If their planet is stable enough! If the beings don't destroy themselves first! If....If....If..... Still no sign of any so far!

[jonnydreads]

1 hour ago, Star101 said:

Maybe.

If their star lives long enough!, If their planet is stable enough! If the beings don't destroy themselves first! If....If....If..... Still no sign of any so far!

I don't really buy into this goldilocks idea if I'm honest, I think the universe is so huge that anything goes, I think theres possibly millions of elements out there, maybe theres no need for water or starlight? who knows.... I doubt we will get the chance to find to either which is depressing lol

[Star101]

Its hard to create ideas and statistics from only 1 instance. 

If you are looking for signs of life outside the "goldilocks" zone, would you recognise it if it hit you?

[SIDO]

Circumstellar Habitable Zones;

95 to 180 billion habitable planets estimated in the Milky Way some estimates are more conservative, this C&P is from Wiki under CHZ's.

If I were attempting to prove life exists elsewhere the Goldie Locks thing is pushing the biggest number of possible places to look.

Studies that have attempted to estimate the number of terrestrial planets within the circumstellar habitable zone tend to reflect the availability of scientific data. A 2013 study by Ravi Kumar Kopparapu put η_e, the fraction of stars with planets in the CHZ, at 0.48,^[4] meaning that there may be roughly 95–180 billion habitable planets in the Milky Way.^[107] However, this is merely a statistical prediction; only a small fraction of these possible planets have yet been discovered.^[108]

Previous studies have been more conservative. In 2011, Seth Borenstein concluded that there are roughly 500 million habitable planets in the Milky Way.^[109] NASA's Jet Propulsion Laboratory 2011 study, based on observations from the Kepler mission, raised the number somewhat, estimating that about "1.4 to 2.7 percent" of all stars of spectral class F,G, and K are expected to have planets in their CHZs.^[110][111]