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Questions tagged [exoplanet]

Questions regarding planets that lie outside the Solar System.

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27 votes
3 answers
6k 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 hundreds of light years in diameter but I suspect ...
Software Framework's user avatar
10 votes
2 answers
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 ...
Curious Layman's user avatar
37 votes
3 answers
2k 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/...
Nick T's user avatar
  • 471
7 votes
2 answers
444 views

Just how "locked" are resonant-chains of exoplanets thought to be? (e.g. K2-138 and TOI-178)

The Phys.org news item Discovery of new planet reveals distant solar system to rival our own outlines the recent announcement of results using AI to help search Kepler photometric (transit-method) ...
uhoh's user avatar
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27 votes
4 answers
3k 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 ...
n_bandit's user avatar
  • 625
5 votes
1 answer
432 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.
Sebastien Palcoux's user avatar
3 votes
2 answers
225 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 ...
Clyde's user avatar
  • 31
58 votes
3 answers
8k 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"?
Guss's user avatar
  • 653
23 votes
10 answers
7k views

Is the closest planet to another planet always the innermost planet?

In our Solar system Mercury is not only the closest planet to Earth on average but also, for the same reason, the closest planet on average to all other planets (Jupiter, Neptune, etc...). Does that ...
Gerardo Furtado's user avatar
15 votes
2 answers
558 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 ...
Larian LeQuella's user avatar
6 votes
2 answers
130 views

After only one eclipse of its X-ray bright primary, how can astronomers estimate the first extragalactic exoplanet's period to be about 70 years?

Phys.org's Astronomers may have discovered the first planet outside of our galaxy links to Di Stefano et al. 2021 A possible planet candidate in an external galaxy detected through X-ray transit (...
uhoh's user avatar
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10 votes
2 answers
3k 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 ...
James K's user avatar
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10 votes
1 answer
378 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 ...
Dashboarrd's user avatar
7 votes
1 answer
968 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 ...
8192K's user avatar
  • 173
5 votes
2 answers
150 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 ...
uhoh's user avatar
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3 votes
1 answer
140 views

Why does the exoplanetary system TOI-178 challenges current theories of planet formation?

I am excited reading the news about ESA's latest exoplanet discovery using CHEOPS. The system TOI-178 consists of (at least?) five planets, following a 18:9:6:4:3 pattern. In the press release, the ...
B--rian's user avatar
  • 5,636
3 votes
1 answer
261 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 ...
uhoh's user avatar
  • 30.7k
23 votes
1 answer
330 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 ...
user avatar
17 votes
2 answers
582 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 ...
Guillochon's user avatar
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17 votes
4 answers
967 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 ...
Jordan's user avatar
  • 388
17 votes
1 answer
491 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 ...
uhoh's user avatar
  • 30.7k
16 votes
7 answers
5k views

Is there enough data in light coming from distant exoplanets for Earth-orbiting telescopes to take a high-resolution photo of it?

NASA’s James Webb Space Telescope has taken very blurry "photos" of exoplanets around distant stars, such as the exoplanet HIP 65426 b, in different bands of infrared light: My question is, ...
user3163495's user avatar
11 votes
1 answer
441 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? ...
called2voyage's user avatar
  • 6,300
10 votes
4 answers
4k views

Why can't we build a huge stationary optical telescope inside a depression similar to the FAST radio telescope?

So first we'll have to find a natural depression or we should create one. I understand you can only see a single portion of the sky since it can't be moved, so my money is on creating an artificial ...
AKR's user avatar
  • 159
8 votes
2 answers
433 views

Are many exoplanets nonsynchronously 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 ...
LocalFluff's user avatar
  • 11.4k
7 votes
2 answers
1k views

Why can we see the Pillars of Creation, but not Proxima B?

I was wondering how is it that we can see the Pillars of Creation (I know they're no longer there too) which are labeled as 6,500 light years away from earth and yet Proxima B is labeled at just 4.2 ...
user6534234's user avatar
7 votes
2 answers
657 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 [the ...
ThePopMachine's user avatar
5 votes
1 answer
273 views

Explanation about the resonance, mean motion resonance and libration

I am studying for a project the dynamics of multi-planetary system in resonance. I have two questions about this domain. In many articles they speak about 'mean motion resonance', what is the ...
Adrien Chimay's user avatar
4 votes
1 answer
114 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 ...
Pranay's user avatar
  • 783
4 votes
2 answers
181 views

How often does the configuration of the Trappist-1 system repeat

My question is simply how long it takes for the 7 known planets in Trappist-1 to be in the same configuration in relation to their host star, and to each-other. Those seven planets are in a 2:3:4:6:9:...
skout's user avatar
  • 309
4 votes
1 answer
483 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 ...
stanley dodds's user avatar
3 votes
1 answer
228 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. ...
uhoh's user avatar
  • 30.7k
1 vote
1 answer
70 views

Which studies prior to 2018 "claimed to find evidence of extragalactic planets in the Andromeda galaxy"? Which instrument was used?

After the first round of popular news items about the "first extragalactic exoplanet" discovery, CNET's Did astronomers find the first planet outside of the Milky Way? It's complicated ...
uhoh's user avatar
  • 30.7k
35 votes
4 answers
3k 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 ...
user10467's user avatar
  • 359
31 votes
2 answers
3k views

Which of the planets would be detected if they were exoplanets?

An (almost-)omnipotent being selects the solar system, presses Ctrl+C, and then Ctrl+V several times, creating copies at distances of 5, 500, 50.000, and 5.000.000 light-years away. All in a direction ...
Ink blot's user avatar
  • 421
25 votes
4 answers
10k views

Is there any planet bigger than a star?

Or a star smaller than a planet? Which star and planet would be an example of this?
asker223's user avatar
  • 377
21 votes
2 answers
1k 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 ...
Victor Stafusa's user avatar
20 votes
1 answer
13k 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 ...
bogen's user avatar
  • 2,356
20 votes
1 answer
4k views

Why are most discovered exoplanets heavier than Earth?

Looking at all discovered exoplanets (4393 exoplanets), I found than only 17 of them (less than one percent!) have masses less or equal to Earth's mass. Why so? Is it because it is very difficult to ...
Peter's user avatar
  • 203
19 votes
2 answers
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 ...
JeanPaul's user avatar
  • 631
16 votes
2 answers
5k views

Is it possible for planetary rings to be perpendicular (or near perpendicular) to the planet's orbit around the host star?

Is it possible for planetary rings to be perpendicular (or near perpendicular) to the planet's orbit around the host star?
Curious Cat's user avatar
15 votes
4 answers
556 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 ...
Sarah Szabo's user avatar
  • 2,043
14 votes
3 answers
2k views

Is the measurement of distance and position of remote celestial bodies accurate?

Considering that light is affected by gravity, how accurate are measurements of distant stars and galaxies? When light passes through objects with great mass, such as Jupiter size planets, stars, or ...
Cris's user avatar
  • 263
14 votes
4 answers
3k 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 ...
seijitsu's user avatar
  • 403
13 votes
2 answers
257 views

Why hasn't VLBI been used to try and image giant exoplanets?

A Jupiter-sized object at 10 pc subtends an angle of 0.0001 arcseconds (100 micro-arcsec) at the Earth. The Event Horizon Telescope interferometry network is capable of a (demonstrated) angular ...
ProfRob's user avatar
  • 156k
13 votes
1 answer
627 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 ...
chaonomy's user avatar
  • 1,119
10 votes
1 answer
802 views

What are the challenges in finding Earth-like planets via the radial velocity method?

[I have re-asked this, because it was a good question by @Banyan, which was deleted whilst I was composing an answer.] Most exoplanets that are found by the radial velocity ("Doppler wobble")...
ProfRob's user avatar
  • 156k
10 votes
1 answer
146 views

How actively is Deep Learning being used in exoplanet identification?

Papers, like this one from Google, show that Deep Learning and Machine Learning are effective in detecting exoplanets from luminosity data provided by telescopes like TESS or Kepler. These models ...
user avatar
10 votes
1 answer
2k views

How would water-ammonia oceans behave?

Scientists strongly suspect that several moons in our solar system have frozen-over oceans of water-ammonia mixture. I've also read speculations on the possibility of surface water-ammonia oceans on ...
n_bandit's user avatar
  • 625
8 votes
1 answer
420 views

Estimates for "undetectable" planets in extra-solar systems

As far as I've been able to determine, it appears there are some significant limitations on our ability to detect exo-planets that are below certain sizes or beyond certain distances from their stars....
Harthag's user avatar
  • 379