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Questions tagged [exoplanet]

Questions regarding planets that lie outside the Solar System.

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Do known exoplanets confirm or refute the Titius-Bode law?

We've had the Titius-Bode law around since the early 1700s or so, suggesting a mathematical sequence to planetary orbits. Since then we've managed to find some planets outside of our solar system. ...
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Is there any habitable exoplanet around Tau Ceti?

I was wondering.. is there any habitable exoplanet around Tau Ceti?
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How do we know that an exoplanet is tidally locked to the parent star?

Often in discussing exoplanets we hear that they are close to the parent star (usually a red dwarf) but then there's a caveat that the planet is tidally locked to that star and that that fact severely ...
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What happened to the third planet in the Kepler-47 system?

In 2012, the discovery paper for the multiplanet circumbinary system Kepler-47 mentioned a potential third transiting planet in the system: A 0.2% deep transit-like event is present at time 2,455,...
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What’s the closest earth like planet we have discovered in our galaxy? [closed]

What’s the closest earth like planet or moon to earth we have discovered in our galaxy?
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Is Naboo's core possible in real life?

In Star Wars, the planet Naboo has a plasma core, instead of a molten one. Can a planet really have a plasma core?
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Hubble Space Telescope (HST) observing modes

I have been reading some literature on using the HST to take spectra of exoplanet atmospheres when exoplanets transit in front of their stars. The literature mention two modes of observations, '...
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Doppler Spectroscopy - Finding mass of an exoplanet

An astronomer, T observed the spectrum of a distant star X. The spectral lines were observed to have tiny blueshifts and redshifts regularly with a period of 1.27 years. T concluded that the star is ...
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Is a precession rate of -0.67 radians/orbit plausible?

I came across the paper Rodin & Starovoit (2018) about the possible existence of a planet around the pulsar PSR B0525+21, which suggests the existence of a 0.387 Earth mass planet with the ...
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Gas Giant temperatures

Sudarsky's gas giant classification predicts the visual appearance of gas giant planets based on their temperatures. But what determines their temperatures in the first place? Is it just the ...
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Largest non-hot gas giants

Excluding 'fluffy' or 'puffy' gas giants that are 'inflated by heat from their stars, what is the maximum radius of a gas giant planet. I keep reading things like "...Jupiter is 'about' as big as ...
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Calculate the orbital phase when plotting the Radial Velocity data of a transitting exoplanet

I'm not quite sure how I find the orbital phase ($\phi$) of a transitting exoplanet. For example, I have this RV data in this article: First of all, I don't know how that phase or "cycles" is ...
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Plausible reason for the Hot Neptune gap

This NASA article talks about how there's a dearth of hot neptune exoplanets that have been discovered so far. https://www.nasa.gov/feature/goddard/2018/in-search-of-missing-worlds-hubble-finds-a-...
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How can we learn the inclination of the orbiting plane of the exoplanets using radial speed method?

I heard about the radial speed method to discover exoplanets a few years ago, however, these questions kept confusing me. If we know a planet star of mess $m$ is orbiting a star by interpreting the ...
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How are exoplanets with 10,000 day periods discovered with the radial velocity method?

The radial velocity technique has apparently been used to discover exoplanets with extremely long orbital periods of ~10,000 days. For example, see this link: https://exoplanetarchive.ipac.caltech....
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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 ...
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Could an ultra-hot Jupiter flare?

Some of the ultra-hot Jupiters (WASP-33b, KELT-9b) have dayside surface temperatures similar to low-mass stars. Would they be capable of producing flares? To be specific, I am asking about the ...
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Distance between two planets [closed]

Planet A and Planet B orbit a sun-like star. Planet A has a semi-major axis of 1 AU from the star. Planet B has an albedo of .8 and has the same radius as Jupiter. When Planet B is observed from ...
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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....
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Would you get the same planet-discovering data for our own system at the same distance we're getting from Earth?

So there's a boatload of planets being discovered around stars in our solar neighborhood. Kepler 22, 638 ly away, was discovered to have a planet Kepler 22b, calculated to be twice the size of Earth. ...
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Where is the exomoon? (Possible discovery of a companion to Kepler-1625b)

The new paper in Science Advances Evidence for a large exomoon orbiting Kepler-1625b (open access!) uses a sophisticated combination of occultation light curve simulation, signal processing and ...
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Exoplanet radius density relation according to NASA exoplanet archive

I downloaded the info from NASA exoplanet archive at: https://exoplanetarchive.ipac.caltech.edu/cgi-bin/TblView/nph-tblView?app=ExoTbls&config=compositepars I named the file "NASA.Composite....
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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 & ...
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Currently proposed ways to distinguish between a really big planet and a really small star

The Next Big Future article Rogue Exoplanet 12.7 times bigger than Jupiter is 20 light years away Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have made ...
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What percentage of gas giant exoplanets are in the habitable zone?

Approximately what percent of exoplanet gas giants discovered so far are in the habitable zones of their stars? I hear that most of them are "Hot Jupiters", orbiting so close to their stars that the ...
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Number of planets in a habitable zone with large moons [closed]

Excluding gas giants, roughly what percentage of planets in the habitable zones of their stars would have large moons like Earth does, as opposed to Mars and its small moons/captured asteroids?
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Can aliens possibly be around us?

I've heard somewhere that when we observe distant galaxies, we actually look into the past. For example, if a planet is 3 million light years away from us, it means that we observe its state as it was ...
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Helium discovered on an exo planet

Why is there so much excitement over helium having been discovered on an exoplanet? Isn't it oxygen that we should be looking for, since this is what is needed for life? What do we need helium for?
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Is there any difference among exoplanets in composition due to host star?

Simply put, would, say, rocky planets orbiting red dwarfs have a noticably different chemical makeup than rocky planets orbiting B-type main sequence stars? Mutatis mutandis gas giants and the other ...
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What makes an exoplanet to orbit around its star backwards?And why did we consider our orbital movement to be forward?

I read somewhere that an exoplanet in the name of HAT-P-7B orbits its star backwards.Why? And why did we consider our orbital movement to be forward?Is there some scientific reason to consider the ...
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Help me identify a cluster [closed]

as I was browsing Nasa's Eyes few days ago, I saved a screenshot, but it seems text is blurrry, supher-485, first letter is S ends with er-485 from as I can read it kinda looked like Cosmic Web, ...
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Detecting habitable planets

From my understanding we detect planets by measuring dips in light intensity from the star the habitable planet is orbiting when it passes by it. There are 2 things I don’t understand about this ...
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How did TESS scientists choose which stars to observe at a “2 minute cadence” in each field?

The BBC news podcast Science in Action episode New Planet Hunting Mission covers the upcoming TESS mission between 01:00 and 07:15 with Sara Seager, TESS deputy ...
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Could diatom blooms affect albedo of an exoplanet?

And perhaps display a seasonal variation if the exoplanet has an axial tilt, providing proof of an Earth-like world supporting at least oceans with microbial life?
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Could Hot Jupiter systems sustain Trojans?

My understanding is that there is a gravitationally stable region between the Sun and Mercury where asteroids could - in theory - orbit for long periods without being perturbed. However these ...
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Can BY Draconis variable stars sustain any form of complex life?

I wanted to ask this, because while I was working on two fictional planets back on the Worldbuilding SE, one of them being habitable, which orbit the 61 Cygni A star of the 61 Cygni binary star system,...
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Is there any habitable exoplanet close to Earth?

I would like to know please if there is any habitable exoplanet close to Earth.
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What does “O I” mean in the context of detected molecules?

I've recently been analysing the Exoplanet Database, and have been looking at the 'molecules' field (molecules detected on the planet or in its atmosphere). They all make sense apart from "O I". It's ...
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Is there a chance that UFOs could be messages from other planets? [closed]

Description Lots of people have thought to of seen UFOs (Unidentified Flying Objects), in fact, more than 83,000 have been reported this year alone. (and it's only February!) But most of the time it'...
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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 ...
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Need help understanding the recent observation of extra-galactic planets!

The new paper Probing Planets in Extragalactic Galaxies Using Quasar Microlensing (also in ArXiv) is too mind-boggling for me to understand exactly what is happening. I have some very basic ...
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Extra-solar identification of binary planets

Pluto and Charon orbit about a common barycenter that isn't inside of either planet. Let's assume that this relationship was scaled up to the point where it could be detected by a search for ...
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Predicting Temperature Variation on Planets with High Eccentricity or Long Diurnal Periods

Whew! That title was a mouth-full, but accurate I hope. What I'm trying to figure out is a model for calculating the approximate temperature variation for a generally earth-like planet (similar ...
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Guess inclination angle from radial velocity measurements

I came upon this question where the situation is I have radial velocity measurements of a star with two circular orbiting exoplanets and the question is how to find out if the inclination angles of ...
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What would theoretically be dissolved in the interior oceans of icy moons and planets?

I know we have some indication of "what's in the water" from the plumes of Enceladas, but would other places be the same. For instance, could the deep liquid water of Titan contain dissolved methane ...
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Star revolving a star [duplicate]

Are there any star system(planet system) where a star revolves around a star? Is it theoretically possible?
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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 ...
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Just how “locked” are resonant-chains of exoplanets thought to be?

update: The BBC News article Citizen science bags five-planet haul announces the system K2-138, also described as a "resonant chain" of planets. However, see the actual paper in ArXiv and Ast. J. ...
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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 ...
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Studies on planets without parent star

I am interested in studies and/or publications about planets that wander in space and are not orbiting around a star or its remnants. These dark and frozen worlds should've got ripped away from their ...