Questions regarding planets that lie outside the Solar System.

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18
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3answers
363 views

Is it odd that our Sun has so many planets?

The internet is abuzz with the new evidence of the possible ninth planet in our Solar System. With those nine objects, the asteroid belt, the Kuiper belt, and everything else in our Solar System - the ...
16
votes
2answers
619 views

If Alpha Centauri A's solar system exactly mirrored our own, what would we be able to detect?

Suppose there was an exact replica of our solar system 4.4 ly away (people included). What would we be able to detect and with what telescope(s)? Which planets? Could we detect radio transmissions and/...
15
votes
3answers
206 views

What practical considerations are there for amateur observations of transiting exoplanets?

Obviously, I am not referring to actual viewing of the exoplanets themselves, but detecting their effects on the brightness of the light emitted from the parent star (as in the diagram below from The ...
14
votes
4answers
274 views

When will we be able to detect Earth-sized exoplanets?

I have heard that the only planets able to be seen outside the Solar system are Jovian-sized planets with the occasional detection of planets three times the Earth's size. But, as far as I know, we ...
13
votes
1answer
145 views

How hot can a planet be?

Given that some exoplanets, particular "Hot Jupiters", orbit very closely to their parent star, how hot can these planets become? What is the hottest exoplanet discovered so far?
13
votes
1answer
133 views

How are the compositional components of exoplanet atmospheres differentiated?

How are exoplanetary atmosphere compositional spectra distinguished from those of the parent star(s), from the composition of the planetary surface or any other factor? Is it actually possible to ...
11
votes
4answers
373 views

What is the most extreme weather found on another planet?

On Venus, there is really inhospitable weather, as well as within the gas giants in our solar system. Are there examples of even more extreme weather on planets found in other solar systems than ours?
11
votes
4answers
228 views

What is the orbital path of the newly discovered star-less planet PSO J318.5-22?

Recent results from Institute for Astronomy at the University of Hawaii at Manoa claim that there is a Jupiter-sized gas giant planet that is independent of a star about 80 light-years from Earth. ...
11
votes
2answers
297 views

Hypothetical beyond Neptune far away planets orbiting the Sun

The planet HD 106906 b was found at 650 AU from its home star, which is not a star much different from the Sun. Fomalhaut b is also a young planet that is orbiting very far away from its sun. These ...
11
votes
1answer
9k views

How many sun-like stars are there in the universe?

After yesterday's announcement of the Kepler telescope finding a huge amount of newly observed exoplanets, i saw a headline claiming that as much as 22% of sun like stars in the universe have planets ...
11
votes
2answers
238 views

Statistics of elements abundance in exoplanets

Recently, I encountered the concept of carbon planets - planets, which would be, unlike the Earth, formed mostly by carbon, instead of oxygen, silicon and magnesium. (I am not counting iron, which is ...
11
votes
1answer
129 views

What percent of planets are in the position that they could be viewed edge-on from Earth? (and thus able to undergo transits)

Star number 12644769 from the Kepler Input Catalog was identified as an eclipsing binary with a 41-day period, from the detection of its mutual eclipses (9). Eclipses occur because the orbital ...
10
votes
2answers
101 views

Do any known exoplanetary/solar bodies have “annular” eclipses similar to Earth's?

This was somewhat inspired by this question but is a bit different: I am interested in if there are any known systems in which the angular size of the eclipsing object is almost the same as the ...
10
votes
3answers
724 views

how far away could we detect that earth has life?

My guess is that life bearing planets are too far apart to be detected. I think we can only find the ones within a sphere around our planet that is 100s of light years in diameter but I suspect life ...
10
votes
1answer
81 views

How close are we to having the technology to measure planetary obliquity for exoplanets?

As far as I can tell, we do not yet have the precision to even put reasonable bounds on an exoplanets obliquity, but wikipedia seems to indicate that this may be possible in the "near future." It ...
9
votes
1answer
266 views

Is it possible for a moon to orbit a planet floating free in the galaxy rather than orbiting a star

This article got me thinking, can a planet hold a moon in orbit if it is just floating in the galaxy by itself not as part of a star system? Can a celestial body even qualify as a planet if it is ...
9
votes
1answer
192 views

Which is the closest exoplanet to Earth?

The closest star to Earth (after the Sun) is well-known: Alpha Centauri, 4.3 light years away. But what about the closest exoplanet to Earth, outside of the Solar System?
9
votes
4answers
355 views

How would we detect an Earth doppelganger planet?

With our current technology, or technology available in the near future (up to 2025), how would we detect a planet exactly like our own, and how close would it have to be to be detectable? Which ...
9
votes
1answer
240 views

What is the current accepted theory for the fate of hot Jupiters?

It is well established that one main feature of many hot jupiters is their close proximity to their parent star, usually the equivalent of being within the orbit of Mercury. So, these planets are gas ...
9
votes
1answer
187 views

Is the surface of TrES-2b actually dark?

The exoplanet TrES-2b is known as the darkest planet ever found, reflecting <1% of the light that hits it. What does it mean in respect to the surface? What would we see below the atmosphere of ...
7
votes
1answer
96 views

What is the process for vetting the 4,175 candidate planets Kepler has discovered?

In the National Geographic article about NASA's announcement of new planets discovered by the Kepler spacecraft, it states that there are 4,175 candidate planets. What is the process for vetting these ...
7
votes
1answer
138 views

Climate modeling of exoplanets

These notes from an exoplanet talk discuss modeling the climate of exoplanets. How would we do that with our current technology? Would data be primarily gathered by spectrum analysis?
7
votes
2answers
107 views

How does gradual crossing over of the Roche limit transform a planet or moon?

Some cartoon simulations (an example) of an object (assume here a large moon with Earth-like density) which crosses the Roche limit of a much more massive giant planet, illustrate a circle suddenly ...
7
votes
1answer
80 views

Could the James Webb Space Telescope detect biosignals on exoplanets?

The James Webb Space Telescope (JWST) which is slated to launch in 2018 will bring us a better view of exoplanets, but will it be sufficient to detect signs of life on at least some of those worlds? ...
7
votes
1answer
88 views

Is it possible that only one hemisphere of a planet has an atmosphere?

Suppose there is a tidally locked planet orbiting a star. The planet's surface consists of a global ocean, that is, liquid water. At the inner hemisphere the temperature is so high that the water is ...
7
votes
1answer
43 views

What observational constraints are there in detecting the presence of volcanism on exoplanets?

This question is somewhat related to my earlier question How are the compositional components of exoplanet atmospheres differentiated?, but this about a specific surface-atmospheric phenomena - ...
7
votes
0answers
128 views

Method to determine the amount of reflected starlight necessary for an exoplanet to be visible from a given distance/angle?

What is the method to determine the amount of reflected starlight necessary for an exoplanet to be visible from a given distance/angle? (Not from occlusion but actually visible on its own.) Further, ...
6
votes
4answers
1k views

Would an exoplanet without axial tilt have no seasons?

Would an Earth analog exoplanet which rotates around a solar analog, but without axial tilt, have no seasons? Would it be similar to how Los Angeles does not have very noticeable seasons compared to ...
6
votes
2answers
193 views

Why are some planets so close to their star?

"Kepler-10b orbits its parent star once every 0.84 days, which means it is more than 20 times closer to its star than Mercury is to our sun" space.com Are there any accepted theories that ...
6
votes
2answers
156 views

What's the name for [the other kind of planet] in a binary star system?

This XKCD what-if talks about rainbows on planets in a binary star system. It points out that there are two types: circumbinary planets, where the planet orbits far from and around both stars [...
6
votes
2answers
131 views

White dwarf's impact on orbiting bodies

Recently the Kepler telescope in its study of white dwarfs detected the first planetary object transiting a white dwarf in the data from the K2 mission. It was consistent with earlier theories' ...
6
votes
1answer
106 views

Is there any way a planet could form independent of a star?

I just recently heard that there are currently no theoretical models that support planet formation without a star, but I can't remember where. So, I thought I would request all of your expertises. ...
6
votes
2answers
679 views

What is the maximum number of planets in the habitable zone?

At present, it seems like we are alone in our solar system. How many earth-like planets would fit into the habitable zone of the solar system? The orbits should be stable for quite a time, i.e. for ...
6
votes
1answer
91 views

Orbital resonances and position of planets

I am interested in quick generation of planetary systems for programs similar to Space Engine or Pioneer Space Simulator. As far as I understand, formation of planets is a complex process and the ...
6
votes
2answers
155 views

Likelihood of a stable system with a dwarf planet's orbit inside that of a gas giant

I keep thinking of various planetary system configurations, and would like to know: What are the fundamental references based on Monte Carlo long-term simulation of planetary systems' evolution that ...
6
votes
1answer
110 views

Exoplanet naming conventions

I'm looking for any exoplanet nomenclature, official, semi-official, proposed, or just a good idea, beyond what can already be found on Wikipedia at http://en.wikipedia.org/wiki/Exoplanet#...
5
votes
1answer
240 views

Are there any Stars we know don't have planets?

We have been looking for planets around other stars for a while (see related Are there any other Earth-like planets in the universe? ) and we are finding lots of planets, some of them are Earth like ...
5
votes
2answers
458 views

Are there any common characteristics of habitable planets?

Recently, over a thousand exoplanets were confirmed in one huge sweep which is a huge achievement and in the mix a dozen or so possibly habitable planets were confirmed as well. This made me wonder, ...
5
votes
1answer
155 views

Planned telescope to detect alien waste-heat

I remember watching a talk by someone who designed a telescope to view a single star at a time. The purpose of the telescope was to detect waste-heat which would presumably be emitted by any ...
5
votes
2answers
136 views

Do most planetary systems have fewer planets than the solar system?

It is my impression that most planetary systems have, at most, three to four planets. Is that real? Or is it just that we lack the ability to detect most planets?
5
votes
1answer
377 views

How can a planet have a 90° inclination?

Planetary systems as we understand it exist from a disk of mass when the parent star is young. That's why all our planets are in the same plane, or close to it. See also Why is the solar system ...
5
votes
2answers
105 views

What does the term alien planet actually refer to?

This article left me wondering what do they mean by the term alien planet? Aren't all planets simply alien by default, or do they mean planets outside our solar system are alien? Do they mean there is ...
5
votes
3answers
230 views

What proportion of planetary systems have been found with 'Hot Jupiters'

According to the NASA website "The strange attraction of Hot Jupiters", one of the main types of exoplanets that have been detected are Hot Jupiters, which are These are behemoth worlds that ...
5
votes
1answer
106 views

Are there any hot jupiters orbiting red dwarfs?

Do we know of any hot jupiters that could be orbiting a red dwarf (or, more probably, orbiting a barycenter between the two)? Is this scenario even physically possible?
5
votes
2answers
216 views

What astronomical observations would give conclusive proof of alien life?

There are several ways we are coming closer to answering the question "is there life elsewhere in the universe?". One is by first understanding very well the origin life on our own planet. Another is ...
5
votes
1answer
113 views

How should exoplanet discoveries affect SETI?

Given that SETI was created before the discovery of exoplanets, has this changed how they search? Would it make more sense to focus efforts on discovered earth like exoplanets?
5
votes
2answers
121 views

Why are so many sun-like stars found in multiple systems? How do planets form in such a situation?

It has been reported that perhaps half of nearby sun-like stars are found in multiple systems. Why is this so common, and how do planets form in such a situation? Kaitlin M. Kratter, “Sibling ...
5
votes
1answer
88 views

Is it conceivable that the presence of chlorophyll (or similar) could be distinguishable from other chemicals on an exoplanet?

If an Earth-like exoplanet had a sufficiently extensive plant biosphere (i.e large forests, aquatic algal mats etc), is it at all conceivable that scientists could spectroscopically detect the ...
5
votes
1answer
67 views

Conditions on Hot Jupiters

Hot Jupiters are close to their parent star - after all, that's why they're so hot. Their atmospheres are thought to be slowly blown away by the parent star, and they will eventually become chthonian ...
5
votes
1answer
56 views

Can visible wavelength spectroscopy study an exoplanet's chemical composition directly?

I know spectroscopy of light in visible wavelengths is very effective for studying and determining the chemical composition of bodies within the solar system and bright objects outside of it. However, ...