Questions tagged [exoplanet]

Questions regarding planets that lie outside the Solar System.

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23
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3answers
3k 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 ...
9
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2answers
3k views

Is it possible that the Sun has a binary partner (the Nemesis Theory) that has eluded detection? [duplicate]

I just recently learned about the theory that our Sun has a small companion star with a 26 million year orbit. This theory came about when it was realized that mass extinction events happened ...
30
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3answers
1k 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/...
54
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3answers
7k views

Where did TRAPPIST-1a go?

According to the NASA announcement and the Wikipedia article on TRAPPIST-1, the planets around the TRAPPIST-1 star are named TRAPPIST-1 b through h. What happened to "TRAPPIST-1 a"?
22
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2answers
981 views

Terrestrial Exoplanet Skies – I've Built a Visual Sky Chart. Is it Accurate?

I'm an artist (and science enthusiast) and I've been trying to find a comprehensive resource that would help me clearly identify likely sky colors (as perceived by human vision) for exoplanets that ...
14
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2answers
356 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 ...
4
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1answer
317 views

Can SETI certify whether or not Proxima b is inhabited by beings using electromagnetic communication?

Can SETI certify whether or not Proxima b is inhabited by beings using electromagnetic communication? By certify I mean by past, present or future observations using technologies available.
7
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1answer
917 views

Is there an upper limit to the mass of terrestrial planets?

The exoplanet Kepler-10c has a mass between 15 and 19 times the mass of the Earth (making it comparable in mass to Neptune), and yet is thought to have a density of about 7g/cm3 and to be a ...
15
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4answers
776 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 ...
15
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2answers
322 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 ...
4
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1answer
367 views

Brown dwarfs and planets

As far as I know, a brown dwarf is a 'star' whose core never underwent a fusion reaction, so it never became a star. So I was wondering if, apart from orbiting a star, is there any difference ...
3
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1answer
360 views

Why don't we use amateur astronomers' telescopes to create a huge interferometer?

Some telescopes in space have been proposed to function as an interferometer. Being placed several hundreds or thousands of kilometers apart they could actual image exoplanets directly. To my ...
12
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1answer
402 views

Orbital velocity of a planet - why is my calculation off by about 10%?

I am not sure if I am doing something wrong, or misunderstanding Reider and Kenworthy (2016). I'm just trying to reproduce the orbital velocities listed in Table 1. The second paragraph of Section II ...
8
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1answer
279 views

How to find Exomoons?

How would we be able to detect Exomoons? We detect exoplanets by seeing if the light gets faint from a star, but could we really use the same method for determining if there is an exomoon around that ...
5
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1answer
251 views

Are many exoplanets synchronously tidally locked like Mercury?

The only tidally locked planet in the Solar system is Mercury. But it is synchronously tidally locked 3:2, because of the relatively high eccentricity of its orbit, so doesn't turn the same side ...
4
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1answer
113 views

Have any planetary systems been found around Population II stars?

I always understood that Population II stars were unlikely to have planets as they were virtually all H and He with very little else. Have recent observations confirmed this, or have planets been ...
0
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1answer
125 views

Are the planets in the TRAPPIST-1 system so close that inhabitants on one planet could see surface details on the other planets?

In a discussion below the Space Exploration question Are there any to-scale diagrams of the TRAPPIST-1 system I was invited to ask a question like this, so I have. Question: Are the planets in the ...
19
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1answer
12k 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 ...
3
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1answer
400 views

Estimates of exoplanets distribution consistent with current data

I am interested in current estimate of distribution of planets of various radii in various distances from their parent star. There is many sources, where one can find database of presently known ...
19
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2answers
658 views

Hypothetical trans-Neptunian planets orbiting the Sun

The planet HD 106906 b was found at 650 AU from its home star, a star not so different from the Sun. Fomalhaut b is also a young planet that is orbiting very far away from its star. These two planets ...
9
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1answer
147 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? ...
8
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1answer
246 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 ...
26
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3answers
2k 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 ...
19
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2answers
2k views

Is there a gas giant orbiting TRAPPIST-1?

I would like to know if besides these planets, astronomers have discovered a gas planet like Jupiter in this system and if on these planets could exist life without a comet protector like Jupiter does ...
15
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4answers
451 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 ...
15
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4answers
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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
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3answers
4k views

Is Earth's 1g solid surface gravity unusually high for exoplanets?

The surface gravities of the Sun’s planets are all close to 1g, 0.38-2.53 (about a factor of e, by chance). The cloud-top gravity of the gas giants is not too interesting here, but I suppose that the ...
6
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1answer
143 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
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2answers
314 views

Average number of exoplanets in a system

I was just wondering what is the normal amount of planets is in a star system, because in my mind 8 planets seems like a relatively large amount. So are we above average? Can we even see all the ...
4
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1answer
67 views

How can a Grade-11 Student avail TESS data and learn to process?

As mentioned, I am a Grade-11 student. I have always been interested in Data Processing activities. This sums up my experience of working on Asteroid hunt Campaign under IASC (International Asteroid ...
3
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1answer
153 views

Have any co-orbital exoplanet pairs been discovered (and not subsequently retracted)?

For this question, I think a good working definition of co-orbital configuration would be two bodies orbiting around a third much larger body in a 1:1 resonance and where neither mass is negligible. ...
2
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1answer
195 views

Can you assume atmosphere height for the purpose of surface pressure calculation?

Given that by definition of scale height an atmosphere thins by a factor of 1/e^x where x is elevation in terms of scale height multiples (See the table here: Definition of Scale Height), can we ...
2
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2answers
88 views

Detection of exo-planets

One method used for detecting exo-planets is to look for a slight dip in the parent star's luminosity as the planet transits the stellar disc. Intuitively, it seems to me that if planetary systems in ...
20
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1answer
233 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 ...
7
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1answer
340 views

How could a 20 inch space telescope “be able to make out Earth-size planets” orbiting alpha Centari?

The NY Times article Telescope to Seek Earthlike Planet in Alpha Centauri System describes a proposed effort to put a telescope into orbit fairly quickly with a narrowly defined purpose - to look for ...
7
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1answer
122 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 ...
6
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3answers
270 views

Can we see evidence of sunspots on other stars

Searching for exoplanets by measuring the change of a stars brightness when an exoplanet transits the star's disk also has the potential to detect exo-sunspots. Have they ever been detected?
6
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3answers
609 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 orbit ...
5
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1answer
117 views

Could iron rain upset tidally locked WASP76b?

The Jupiter mass planet WASP76b orbits its 1.5*Sunmass star at 0.03AU and is tidally locked. The day side heats to 2400C which vaporizes metals, including iron observed in its atmosphere. The balmy ...
5
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2answers
1k 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, ...
4
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2answers
824 views

Motion of rogue planets

Two Questions: 1) Are rogue planets in motion, i.e. are they just wandering freely in space or stationary? 1) Do rogue planets have defined path or a one which can be anticipated? I understand that ...
4
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2answers
82 views

What's still needed before we can observe orbits of exomoons thereby weighing exoplanets?

Comments below this answer to How do we weigh a planet? point out that we currently cannot (or at least have not) detect moons around exoplanets, much less measure the sizes and periods of their ...
4
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1answer
186 views

Do planets form around lone stars, multiple stars, or both? Do we know this yet?

Since about 1990 astronomers been able to detect planets around other stars, using a couple different techniques, which is amazing. By this point, do we know whether planets form only around single ...
3
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2answers
137 views

How to name planets outside our galaxy?

Recently, planets outside our galaxy have been discovered. How would be the convention to naming these planets? As far as I know, it seems that there is no standard for naming exoplanets even in our ...
3
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1answer
559 views

What are the differences between TESS and PLATO exoplanet telescopes?

Within a year now it has been decided to launch TESS in 2017 and PLATO in 2024, space telecopes of NASA and ESA. They seem to have very similar science goals, both searching for transiting Earth sized ...
3
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2answers
94 views

Can we measure comets in a similar way to exoplanets?

A 2km comet at 40AU's can dim a sun sized star at 100 light years by 3%, and a 10km comet can cause an eclipse (is that right?) So would 2,3,10 km objects be easy to measure via star dimming if we had ...
2
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1answer
91 views

Low mass cut-off for the Dharma Planet Survey's detection of habitable planets around 40 Eridani A?

News of the discovery of a potentially habitable planet around the star 40 Eridani A (about 16 light-years away) is interesting for reasons including a 1991 letter described below in Sky & ...
2
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1answer
100 views

Why would a tidally-locked rocky planet have a first-order spherical harmonic surface temperature distribution?

The new Letter to Nature Absence of a thick atmosphere on the terrestrial exoplanet LHS 3844b (also ArXiv) analyzes the thermal infrared light curve from the system (about 4.5 to 5.5 um). The planet ...
2
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0answers
33 views

Help understanding why these two sub-Hill sphere moon stability limits are so different?

Comments under this answer to What orbital period would produce one New Moon (and one Full Moon) each year? What other effects would this produce? link to Stable satellites around extrasolar giant ...
2
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0answers
32 views

Orbital plane evolution and planet discovery via transit method [duplicate]

I'm aware that our solar system is largely/roughly on a single orbital plane, but haven't other star system's orbital planes been scrambled by billions of years of interaction? If so - how much ...