Astronomy

Where is the exomoon? (Possible discovery of a companion to Kepler-1625b)

Where is the exomoon? (Possible discovery of a companion to Kepler-1625b)


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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 statistical analysis to show that there is a significant chance that they have identified an exomoon, a moon orbiting an exoplanet.

But it's too sophisticated for me to understand how this Hubble data indicates a potential moon. Terms like "detrending", "Markov chain Monte Carlo", and "Bayesian evidences" are beyond me.

Is it possible to choose one of those plots and add an arrow to say "this blip here, this is Kepler-1625b potential moon"? If not, is it possible to at least explain in a simple way what it is from this analysis that has led them to believe there may be a moon there?

Abstract:

Exomoons are the natural satellites of planets orbiting stars outside our solar system, of which there are currently no confirmed examples. We present new observations of a candidate exomoon associated with Kepler-1625b using the Hubble Space Telescope to validate or refute the moon's presence. We find evidence in favor of the moon hypothesis, based on timing deviations and a flux decrement from the star consistent with a large transiting exomoon. Self-consistent photodynamical modeling suggests that the planet is likely several Jupiter masses, while the exomoon has a mass and radius similar to Neptune. Since our inference is dominated by a single but highly precise Hubble epoch, we advocate for future monitoring of the system to check model predictions and confirm repetition of the moon-like signal.


"Detrending" refers to removing systematic effects that are caused by the spacecraft, detector or the environment and which are not part of the particular star. The systematic trends can be caused by a large variety of things; the main ones affecting Kepler are drifts in position and focus, thruster firings to compensate for angular momentum build up in the reaction wheels and the roll of the spacecraft every quarter. Because these trends are systematic and affect all the stars that Kepler sees in a similar way, the effects can be modeled and the trends removed - detrending. There are some examples in slide 15 and 16 of this Kepler workshop presentation which shows the "raw" brightness measurements (labeled 'SAP') and the detrended data on the right (labeled 'PDC').

You can see examples of this in the Supplementary Materials. On page 47 in Figure S2, you can see the data before detrending and you can see the dips caused by the transiting exoplanet (Kepler-1625b) but these are superimposed on long-term upwards or downwards slopes or curves. Detrending removes these effects (which will be common to all the stars, not just to Kepler-1625b's star) allowing you to get corrected flat light curves, enabling the search for the much smaller exomoon signal.

The evidence for the exomoon is in two parts. The timing of the planet transit that was observed by HST in October 2017 was 77.8 minutes early compared to the predicted time from the Kepler transits. This is shown (but not very well) in Figure S12 in the Supplementary Materials. If there was no exomoon or anything else tugging on Kepler-1625b, we would have expected the HST transit (the data point at transit epoch 7) to be on the extended black prediction line at an O-C value (y axis) of +77.8 minutes, ( off the top of their plot as it scaled). The second piece of evidence is that is if the transit is early, then they should expect to see the shallower/smaller transit of the exomoon after the transit as it would be on the other side of the orbit with the exoplanet. This is what they show in the bottom half of Figure 4; no matter which detrending method they use for the HST data, they see a small shallow dip after the main transit is over, centered around a time (x value) of 3056.25. This gives more confidence that the exomoon interpretation is real and not an artifact of the detrending process.

What they are saying after Table 1 is that the Δχ2 (the measure of the change in the goodness of fit of the model as you add extra things to the model) is better with the moon models (models Z and M) over one that just accounts for the transit timing variations (model T). This is because the presence of the exomoon is predicted to cause changes in the length and depth of the exoplanet transit but these are harder to measure than the change in timing.


Monte Carlo refers to a technique of running multiple simulations, each with the input data very slightly changed, usually one variable at a time. After teens or hundreds of thousands of simulations you end up with a probability plot - if these trend towards a particular distribution you can gain confidence that the data is correct.

Bayesian analysis looks more at similarities (which is why it is often used for identifying spam: if it looks more like these thousand examples of spam than those thousand valid emails then it probably is spam)

So this work uses probability theory, and the specific tools mentioned to provide a likelihood measure. And in this case, the balance of probability from the data is that it is an exomoon.

So there will not be a blip that looks like a moon - there will be a vast cloud of data that happens to be more similar to possible models of data expected from an exomoon than from other alternatives considered.


Possible exomoon signal found

Strong hints have been found of a possible exomoon candidate orbiting a gas giant planet over 4,000 light years away in the constellation of Cygnus the Swan. Should the moon be confirmed later this year by the Hubble Space Telescope, it will be the first moon ever discovered around a planet beyond our Solar System.

The potential discovery has come from the Hunt for Exomoons with Kepler collaboration, which is led by David Kipping of Columbia University in New York. The project uses observations collected by NASA’s Kepler Space Telescope, which watches for dips in starlight as planets cross, or ‘transit’, the face of their host stars and block some of the light.

The idea behind hunting for exomoons is that natural satellites should also cause a dip in the starlight, either just before or just after their parent planets transit. However, given the size of moons compared to their planets, the dip in light caused by an exomoon should be small and hard to discern, even for Kepler.

To even the odds, Kipping’s team stacked together multiple ‘light curves’ (graphs showing how a star’s light output changes over time while a planet is transiting it) for each of the 284 planets they were studying, looking for recurring dips that could be attributed to exomoons. They only found one strong candidate, accompanying the planet Kepler-1625b.

At present Kipping’s team, which includes his Columbia colleague Alex Teachey and citizen scientist Allan Schmidt, are remaining cautious about the potential discovery. The signal of the possible exomoon was seen during three consecutive transits by Kepler, but that’s not sufficient to conclusively confirm the moon exists. The next transit is set to take place in October 2017 and the team have already acquired time on the Hubble Space Telescope to observe the planet and, hopefully, confirm that the moon exists.

Giant moon

If it does exist then it is an exceptionally strange moon quite unlike anything in our Solar System. The planet is enormous, with ten times the mass of Jupiter, while the proposed moon has a mass equivalent to Neptune. In some ways the system could be classed as a double planet, and it is unlikely that a moon of this size would have formed in orbit around its planet.

Planetary formation can be a chaotic affair, with planets capable of migrating inwards during their early growth phase as the protoplanetary disc of gas and dust encircling their star saps the planets’ angular momentum. So as Kepler-1625b migrated inwards, it may have run across a Neptune-sized world that it captured.

In this case, Kepler-1625b may have gained a ‘moon’, but theoretical models predict that normally migration is bad for moons, with gravitational encounters between planets stripping moons away from their parent worlds. The dearth of moons in the sample of 284 exoplanets studied by Kipping’s team suggest that these models are correct, meaning that the observations also imply that migration is a common occurrence in exoplanetary systems.

However, finding moons with masses similar to Earth’s Moon, or the Galilean moons of Jupiter, is a tough proposition and it is not yet certain how rare smaller moons really are. Should they be uncommon, then. the lack of moons will not necessarily impact the habitability of exoplanets. In the 1990s the French astronomer Jacques Laskar of the French National Centre for Scientific Research concluded that the presence of a large moon was important for stabilising the obliquity of Earth and hence our planet’s long-term stable climate. However, more detailed simulations run by Jack Lissauer of NASA’s Ames Research Center found that even without the Moon, Earth would wobble on its axis by only ten degrees, which is not enough to render the climate uninhabitable. Meanwhile, Lissauer also discovered that fast-spinning planets (with days less than ten hours long) or backwards-spinning worlds are able to stabilise their tilts without requiring the presence of a large moon. Therefore, the lack of exomoons need not be a barrier to habitable environments on exoplanets.


Did the Hubble telescope find the 1st exomoon?

Astronomers recognize eight major planets in our solar system, with 200 orbiting moons known so far. Much farther away, they’ve discovered nearly 4,000 exoplanets orbiting other stars, but, to date, no exomoons have conclusively been found, despite some earlier possibilities. On Wednesday, however – October 3, 2018 – astronomers announced new evidence for what could be the first true discovery of an exomoon. It appears to orbit the planet Kepler-1625b, 8,000 light-years away, in the direction of the constellation Cygnus the Swan, high in the west on October evenings.

Astronomers David Kipping and Alex Teachey, both of Columbia University, used data from both the planet-hunting Kepler spacecraft and the Hubble Space Telescope to discover the possible exomoon. It’s a saga that’s been unfolding for these astronomers over several years, and the final results still aren’t in … but the new evidence is tantalizing. If an exomoon does indeed orbit Kepler-1625b, Kipping said:

The closest analog would be picking up Neptune and putting it around Jupiter.

If it can be confirmed, this first known exomoon also presents astronomers with a riddle. Such large moons don’t exist in our own solar system. This discovery might require experts to revisit their theories of how moons form around planets. Thomas Zurbuchen at NASA headquarters in Washington, D.C., commented:

If confirmed, this finding could completely shake up our understanding of how moons are formed and what they can be made of.

The scientific study of a possible exomoon for Kepler-1625b was published Wednesday in the peer-reviewed journal Science Advances.

Just as most planets outside our solar system have never been seen directly, we don’t have a direct image of this possible exomoon.

“It was definitely a shocking moment to see that Hubble light curve, my heart started beating a little faster … ” said astronomer David Kipping (left). He and Alex Teachey (right), both of Columbia University, may be co-discovers of the 1st exomoon.

Instead, astronomers have discovered most known exoplanets – and this exomoon – during their passages in front of their stars. Such an event is called a transit, and it causes a tiny dip in the star’s light. The transit method has been used to detect most of the known exoplanets cataloged to date.

Transit signals from distant exoplanets are vanishingly small. That is why the search for exoplanets went on for decades before the first exoplanets were confirmed in the 1990s. Exomoons are even harder to detect than exoplanets because they’re smaller, and their transit signal is weaker. Exomoons also shift position with each transit because the moon is orbiting the planet.

David Kipping has spent about a decade of his career looking for exomoons. In 2017, he and his team analyzed data from 284 exoplanets discovered by the planet-hunting Kepler spacecraft. They looked at exoplanets in comparatively wide orbits, longer than 30 days, around their host stars. The researchers found one instance, in Kepler-1625b, of a transit signature with intriguing anomalies, suggesting the presence of a moon. Kipping said:

We saw little deviations and wobbles in the light curve that caught our attention.

Kipping then requested time on the Hubble Space Telescope. The new Hubble results – though inconclusive – appear to confirm the earlier finding of an exomoon for Kepler-1625b. The announcement of the discovery at HubbleSite explained:

Based upon their findings, the team spent 40 hours making the observations with Hubble to study the planet intensively — also using the transit method — obtaining more precise data on the dips of light. Scientists monitored the planet before and during its 19-hour transit across the face of the star. After the transit ended, Hubble detected a second and much smaller decrease in the star’s brightness approximately 3.5 hours later. This small decrease is consistent with a gravitationally-bound moon trailing the planet, much like a dog following after its owner.

Unfortunately, the scheduled Hubble observations ended before the complete transit of the candidate moon could be measured and its existence confirmed.

A companion moon is the simplest and most natural explanation for the second dip in the light curve and the orbit-timing deviation.

It was definitely a shocking moment to see that Hubble light curve my heart started beating a little faster and I just kept looking at that signature. But we knew our job was to keep a level head and essentially assume it was bogus, testing every conceivable way in which the data could be tricking us.

Earth’s moon is known to be a major factor in the evolution, possibly even the presence, of life on our planet. This possible exomoon and its host planet lie within their star’s habitable zone, the region around a star where liquid water might exist on planetary surfaces. Could the planet, or its moon, be life supporting? The answer is: probably not. Both the exoplanet Kepler 1625b – and its possible exomoon – are gaseous, making them unsuitable for life as we know it.

These astronomers said that future searches for exomoons:

… will target Jupiter-sized planets that are farther from their star than Earth is from the sun. The ideal candidate planets hosting moons are in wide orbits, with long and infrequent transit times. In this search, a moon would have been among the easiest to detect because of its large size.

Currently, there are just a handful of such planets in the Kepler database.

Whether future observations confirm the existence of the Kepler-1625b moon, NASA’s upcoming James Webb Space Telescope will be used to find candidate moons around other planets, with much greater detail than Kepler.

Artist’s concept of a possible Neptune-sized moon, orbiting a planet several times larger than Jupiter – our solar system’s largest planet – in a distant solar system, some 8,000 light-years away. Image via HubbleSite.

Bottom line: Astronomers at Columbia University found evidence in Kepler spacecraft data in 2017 suggesting an exomoon orbiting Kepler-1625b. They then requested time on the Hubble Space Telescope, and the new Hubble data boosts the claim – but does not prove conclusively – that this moon exists.


Has NASA’s Kepler Space Telescope detected first exomoon?

Two scientists have found evidence that an exoplanet found by NASA’s Kepler Space Telescope may have a Neptune-sized moon orbiting it.

Close to 4,000 exoplanets have been discovered since the 1990s. If confirmed, this discovery would be the first known exomoon.

Columbia University astronomers Alex Teachey and David Kipping first suspected the presence of a moon around the planet Kepler-1625b when studying Kepler data on 284 exoplanets with orbits of 30 days or longer in a search for exomoons. Kepler uses the transit method, which involves measuring the regular dimming of a star’s light caused by an orbiting planet passing in front of it, to indirectly detect exoplanets. When analyzing transit data on Kepler-1625b, they saw anomalies suggesting the possible presence of a moon.

“We saw little deviations and wobbles in the light curve that caught our attention,” Kipping stated.

To further search for this natural satellite, Teachey and Kipping observed the planet, located an estimated 8,000 light years away in the constellation Cygnus, for approximately 40 hours, which included its 19-hour transit in front of its star as well as the periods before and after the transit, using the Hubble Space Telescope (HST).

Two unusual phenomena surprised the astronomers. First, the planet passed in front of the star approximately an hour earlier than predicted. Second, three-and-a-half hours after the transit, a much smaller second transit occurred, which involved a very slight dimming of the star’s light.

Both anomalies could indicate the presence of a moon in orbit around the planet. When planets have large moons, the two objects orbit a common center of gravity. This could cause a wobble in the planet’s orbit, causing it to deviate from its predicted location and transit its star earlier than expected.

The second, much smaller transit could have been caused by a moon that follows or trails after its parent planet.

Unfortunately, the scientists’ time on Hubble ended before they could completely observe the second transit.

Because their transit signals are weaker than those of planets and their positions change as they orbit their parent planets. This makes exomoons much harder to detect than the worlds that they orbit.

While Kepler 1625b’s wobble could be caused by the gravitational pull of another planet orbiting the parent star rather than by an orbiting moon, Teachey and Kipping believe a moon is the most likely explanation.

“A companion moon is the simplest and most natural explanation for the second dip in the light curve and the orbit-timing deviation. It was definitely a shocking moment to see that light curve–my heart started beating a little faster, and I just kept looking at that signature,” Kipping said.

Kepler-1625b and its possible moon are both located in the habitable zone of the parent star, Kepler-1625, a Sun-like star about eight percent more massive than the Sun. Estimated to have a mass several times of Jupiter, the planet is almost certainly gaseous and not likely to support life as we know it.

Teachey and Kipping believe the moon is approximately the size of Neptune, making it larger than any moon in our solar system. They estimate it to be 1.5 percent the mass of its planet and the mass ratio between planet and moon to be close to that of the Earth-Moon system. At this size, the moon, tentatively designated Kepler-1625b-i, is likely to be gaseous as well.

Further efforts to find exomoons will likely focus on Jupiter-sized planets that orbit their stars at distances greater than the Earth orbits the Sun. Planets in wide orbits take longer to transit their stars and are likely to have big moons, which should make them easier to find than small ones.

The James Webb Space Telescope (JWST), scheduled for launch in 2021, should make it possible for scientists to find even the smallest exomoons, Teachey said.

“This intriguing finding shows how NASA’s missions work together to uncover incredible mysteries in our cosmos. If confirmed, this finding could completely shake up our understanding of how moons are formed and what they can be made of,” emphasized Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate.

A paper on the finding has been published in the journal Science Advances.

Video courtesy of NASA Goddard

Laurel Kornfeld

Laurel Kornfeld is an amateur astronomer and freelance writer from Highland Park, NJ, who enjoys writing about astronomy and planetary science. She studied journalism at Douglass College, Rutgers University, and earned a Graduate Certificate of Science from Swinburne University’s Astronomy Online program. Her writings have been published online in The Atlantic, Astronomy magazine’s guest blog section, the UK Space Conference, the 2009 IAU General Assembly newspaper, The Space Reporter, and newsletters of various astronomy clubs. She is a member of the Cranford, NJ-based Amateur Astronomers, Inc. Especially interested in the outer solar system, Laurel gave a brief presentation at the 2008 Great Planet Debate held at the Johns Hopkins University Applied Physics Lab in Laurel, MD.


Exomoon or No Exomoon?

By: AAS Nova July 3, 2019 1

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Last October, the first discovery of a potential exomoon was announced. But is Kepler-1625b-i an actual moon in another solar system? Or just an artifact of data reduction?

Artist’s impression of the exomoon candidate Kepler-1625b-i and its host planet and star.
NASA / ESA / L. Hustak (STScI)

A Tricky Business

Moons are a useful diagnostic — they can provide all kinds of information about their host planets, like clues to formation history, evolution, and even whether the planet might be habitable. What’s more, exomoons themselves have been indicated as potential targets in the search for life: while a habitable-zone gas-giant planet might not be an ideal host, for example, such a planet could have moons that are.

Given all we stand to learn from exomoons, it’d be great to find some! But for all that our solar system is chock full of moons (at last count, Jupiter alone hosts 79!), we’ve yet to find any sign of exomoons orbiting planets beyond the solar system.

A montage of Jupiter and its four largest moons.
NASA / JPL

This may well be because exomoon signals are difficult to spot. Not only would an exomoon’s signal be tiny compared to that of its host planet, but we also would need to separate that signal from the host’s — a tricky business. Throw in some instrument systematics to obscure all the data, and exomoon identification becomes even more of a challenge.

For these reasons, it was a pretty exciting announcement last fall when Columbia University astronomers Alex Teachey and David Kipping presented Kepler-1625b-i, a signal that they argued represented an exomoon around the gas giant Kepler-1625b. But a healthy dose of scientific caution has sent other teams scrambling to explore these data and draw their own conclusions — and one of these groups is calling the exomoon discovery into question.

Waiting for Consensus

Best-fit models for the Kepler 1625 light curve assuming a planet and no moon (top) or moon (bottom). Data as analyzed by Kreidberg et al. are on the left (blue) data as analyzed by Teachey&Kipping are on the right (red). Kreidberg et al. find that the best fit is given by the no-moon model. Click to enlarge.
Kreidberg et al. 2019

Led by Laura Kreidberg (Harvard-Smithsonian Center for Astrophysics), a team of astronomers has independently analyzed the same Hubble transit data that Teachey and Kipping used to identify their exomoon candidate. Unlike the other group, however, Kreidberg and collaborators found that the data are best fit by a simple planet transit model — the presence of an exomoon isn’t necessary or indicated.

According to Kreidberg and collaborators, the discrepancy between their results and Teachey and Kipping’s is most likely due to differences in data reduction. Teachey and Kipping have responded to this work with additional analysis in a recent paper submitted to AAS journals, but the debate is far from settled.

So is there an exomoon, or isn’t there? We don’t know yet, but that’s okay!

The case of Kepler 1625 is a beautiful illustration of the messy reality of the scientific process: sometimes the data don’t immediately spell out an answer, and it takes more time, more analysis, and likely more observations before the scientific community reaches a consensus. This isn’t a bad thing, though — this is science being done right! Keep an eye on the story of Kepler 1625b-i going forward we’re bound to continue to learn about this maybe/maybe-not exomoon.

Citation

“No Evidence for Lunar Transit in New Analysis of Hubble Space Telescope Observations of the Kepler-1625 System,” Laura Kreidberg et al 2019 ApJL 877 L15. doi:10.3847/2041-8213/ab20c8

This post originally appeared on AAS Nova, which features research highlights from the journals of the American Astronomical Society.


Discovery of Potential Exomoon Raises Hopes of Real-Life Pandora or Endor

The potential discovery of a huge exomoon around a gas-giant planet is stirring up some sci-fi fantasies.

Yesterday (Oct. 3), researchers announced they had spotted evidence of a Neptune-size moon circling the planet Kepler-1625b, which is about three times more massive than Jupiter.

The candidate moon, which still needs to be confirmed by follow-up observations, is likely gaseous and therefore not a great bet to host life as we know it, the scientists said. But there could be habitable exomoons out there, just waiting to be found.

"We're hoping that one day we might really find something like a true Earth analogue in a moon," Alex Teachey told reporters on a conference call on Monday (Oct. 1). Teachey, a third-year graduate student at Columbia University in New York, was first author of the research announcing the potential moon.

"That's something more akin to what people are thinking of when they think of an 'Avatar' Pandora," he added.

In James Cameron's 2009 film "Avatar," humans visit Pandora, the fifth moon of the (fictional) gas giant Polyphemus, which is portrayed as orbiting the real-life star Alpha Centauri A. (Don't confuse the "Avatar" world with the real-life Pandora, which is a small, heavily cratered moon of Saturn.) The film portrays Pandora as a rocky world, just smaller than Earth in terms of mass and radius and lush with unusual life.

But Teachey said Pandora isn't his go-to world when thinking about exomoons. "I'm partial to Endor myself," he said. "I'm more of a 'Star Wars' fan."

Endor is portrayed as roughly one-third the diameter of Earth and scovered in dense woodlands. Its most famous inhabitants are the fierce but adorable Ewoks, though it is home to several other species in the "Star Wars" universe. Unlike Pandora, Endor orbits not one but two suns.

Teachey and study co-author David Kipping, also of Columbia, were very cautious about their prospective find, emphasizing that their focus remains on confirming the existence of the exomoon around Kepler-1625b rather than musing about its potential to support life. (Though the planet and moon do appear to orbit in their star's "habitable zone.")

"To be honest, we never really worried much about habitability, just because they're both gas giants, so it really wasn't something we spent any effort or time worrying about," Kipping said during Monday's teleconference.

However, the researchers did make a few interesting observations, which they stressed were quite speculative.

For instance, the star at the center of the system is about 10 billion years old &mdash roughly twice the age of Earth's sun &mdash and is therefore nearing the end of its life. That means this star, and the planet and moon it shines upon, were probably much cooler in the past, Kipping said. As the star has warmed in recent millennia, the newfound moon may have also grown hotter, causing its atmosphere to expand. That could have produced a rocky moon with a bloated atmosphere that looks like a Neptune-size object.

"It's certainly possible that the moon is actually quite low-mass," Kipping said. "Some of our models allow even Earth-mass for the moon."

Such a natural satellite would be more in line with the fictional worlds of "Avatar" and "Star Wars."

Another possibility is that the moon, whatever its size, has moved away from its planet over the eons. Today, the exomoon is roughly 1.9 million miles (3 million kilometers) from Kepler-1625b. However, scientists know that Earth's moon is gradually moving away from our planet at a rate of about 1.5 inches (4 centimeters) per year.

The candidate exomoon &mdash signs of which were spotted by NASA's Kepler and Hubble space telescopes &mdash may have similarly edged away from its planet over time, so it could have been much closer billions of years in the past, Kipping said.


After Exoplanets, Kepler Hunts Exomoons

When looking for exoplanets, scientists monitor the “planetary transit” and look for the brightness and occultation of the associated star.

As a planet passes in front its star, it will deflect a part of the starlight with respect to the observation point.

When a massive body (planet) passes a distant star of the celestial vault, it affects the path of light. This results in a very characteristic light deformation, or what’s called the gravitational lens effect, which indicates the presence of an exoplanet.

In some cases, when there’s a small additional disturbance, a gravitational microlensing effect, that suggests the presence of another celestial body, like a moon orbiting an exoplanet. This is, from our perspective, an exomoon.

Based on this method, Kepler manages to identify new exoplanets regularly. But the mission is even more complicated with exomoons.

The rarity of the phenomenon, exoplanets with exomoons, makes the task harder. For Kepler to detect the deviations of light and determine the possible presence of moon-like celestial bodies, scientists have to wait for a perfect alignment between the star, the exoplanet, and in this case, its exomoon.

Using the same methodology, Kepler carries on the celestial quest to find whether some of these exoplanets have moons orbiting them.


First Exomoon Possibly Discovered Orbiting in a Distant Star System

Researchers from Columbia University think that they may have found what could be the first confirmed exomoon one day. Credit: NASA Astronomers say they may have found the first confirmed exomoon, or moon orbiting a planet outside of our solar system. However, the pair of astronomers behind the find say it's much too soon to completely prove the exomoon’s presence. After looking through recent data from NASA’s Kepler space telescope, Alex Teachey, a graduate researcher in the department of astronomy at Columbia University, and David M. Kipping, an assistant professor in the same department, spotted evidence that an exomoon might orbit the Jupiter-sized exoplanet Kepler-1625b. Transiting planets are worlds that can be detected by a drop in light as they pass in front of their home stars. An when Kepler observed each of 284 transiting planets, the telescope showed a short dimming. The researchers requested and were awarded 40 hours of time to observe these planets’ transits using the Hubble Space Telescope, which is about four times more precise than Kepler. The researchers hoped to see two short dimming moments that might signal the presence of an exomoon around one of these transiting planets. They also helped to use Hubble to see any gravitational effects that a moon would have on the exoplanet, like changing its transit start time. About three and a half hours after Hubble observed Kepler-1625b finish transiting, the telescope saw a second short dimming. The two signals together looked like a moon “trailing the planet like a dog following its owner on a leash,” Kipping said in a statement. While the researchers have yet to confirm the presence of an exomoon, they estimate that this moon would be about the size of Neptune. Teachey said that it’s likely this possible exomoon is “in some ways the lowest hanging fruit. We should expect to see something like this before we see the really small moons.” These researchers also found that the exoplanet passed in front of its star about 80 minutes earlier than they anticipated. This observation suggested transit time variations, which is a major signal that there could be an exomoon. “It’s certainly plausible that another planet in the system could induce transit timing variations,” Teachey said. However, during its four-year mission, Kepler found no evidence for a second planet in the stellar system. Still, it is possible that there is a second planet in the system external to Kepler-1625b whose transit we can’t see, Teachey said. But currently, “we do obviously think that the moon is the best explanation,” he said, adding that “just like any other good skeptical scientist, we’re saying ‘maybe’.” This still doesn’t prove the existence of an exomoon around Kepler-1625b. To further confirm the exomoon, the team will need to continue to observe the transit events in this system. As stated in a teleconference earlier this week, the researchers will put in a proposal to use Hubble to observe the next transit event in May 2019. The possible exomoon discovery was published in Science Advances on October 4.


The Exoplanet Kepler-1625B With Its Planned Moon

The Exoplanet Kepler-1625B With Its Planned Moon. Exomoon Candidates The Size Of Neptune Can Be The Captive Nucleus Of A Giant Planet. The mysterious Kepler-1625B-I and his parent planets can be brothers. Artistic representation of the exoplanet Kepler-1625B with its planned moon. Which is believed to be the size of Neptune. A new study suggests that the first serious exomoon candidate is probably the occupying nucleus of a giant baby planet.

In October 2018, astronomers Alex Tecchi and David Kipping of Columbia University announced that they would testify about the world in the form of Neptune. The Kepler-1625b, a massive alien planet about 8,000 light years from Earth. This was great news: if confirmed, the new world, known as Kepler-1625B-I, would be the first moon discovered beyond our solar system. But confirmation has proved difficult.

Techey and Kipping insisted at the time that the detection, using observations from NASA’s Kepler and the Hubble Space Telescope, was temporary. Another research team has argued against the existence of Kepler-1625B-I, and another has insisted that the data is inconclusive at this time. Therefore, a year later, Kepler-1625B-I remains a candidate instead of a world candidate.

However, this situation did not prevent other scientists from trying to understand how the potential Exomoon arose. In fact, a new study addressed that question and got an intriguing answer. Astronomers find that the Kepler-1625B-I is approximately 10 times more massive than Earth. The object appears to be orbiting its parent planet as Jupiter at an average distance of 1.9 million miles (3 million kilometers).

Mani L. of UCLA At the Bhowmick Institute of Theoretical Physics, Bradley Henson. The Kepler-1625B-I seen on the planetary satellites of the solar system is probably “the planetary satellites of the solar system have a much greater mass and angular momentum. It was published online today (October 2) in Advances of Science. The parameters of Kepler-1625B-I are compared to those of planets that have recently orbited low-mass stars, Hanson wrote.

It is not clear why Kepler-1625B-I is formed in the same way as the moons of the Solar System. The great moons of Jupiter, for example, are probably covered with a disk of material that orbits the newborn planet a long time ago. Modeling work suggests that the Kepler-1625B-I is much larger in this way, Hansen said.

t is possible that the Exomoon candidate is an ancient planet that was gravitationally occupied by Kepler-1625b. Which is twice as massive as Jupiter. But it doesn’t work either. All the landscapes that assemble. Capture Kepler-1625B-I after the host planet is formed suffer the problem that they produce a moon that is too small or too close,” Hanson Es wrote.

Instead, his new modeling job suggests that both bodies were captured shortly after birth. It is likely that two ascending objects occupy the same orbital neighborhood: a portion of space around an astronomical unit (AU) of the host star. An AU is the average Earth-Sun distance, approximately 93 million miles or 150 million km. In this scenario, the planetary nucleus that becomes Kepler-1625B produces more gas than its neighbor, strengthening its dominance in the eternal relationship.

The way gas accumulation works is a very strong function of the mass, Hansen told Space.com. If you move a little, you start moving very fast. So it is essentially a winning situation, he said. One of them captured all the gases in the surrounding area and became a gas giant. The one that crawled a little got stuck in this main phase and due to the increased gravity [of its neighbor’s satellite]. Even in this stable state.

The Kepler-1625B-I is likely to have so much gas that it is not a good terrestrial-planetary analog, Hansen said. Therefore, even if the potential Exomoon resides in the habitable zone of its host star. The range of distances where liquid water may exist on the surface of the world, the Kepler-1625B-I is probably not a great candidate for life as the earth.

A common occurrence? Elements of this landscape may have played in our own neck of the cosmic forest, Hansen said. For example, it is possible that Neptune and Uranus are giant gaseous protocores that originated in the kingdom of Jupiter and Saturn. In these two later worlds the head of engulfing gas begins, the idea continues.

Iinstead of gravity, occupies Neptune and Uranus, tilting them both to their current location. In fact, this process can help explain the abundance of the mass world of Neptune in the Milky Way galaxy. Which appears to be higher than expected by traditional planetary formation models. If we begin to take into account the fact that multiple nuclei can interact in the same places, it is possible that not everyone becomes a giant planet, he said.

This may be this race against time. The search for a possible Exomoon raises the hopes of a real-life Pandora or Andor In search of mini moons: Exomoon could have its own satellite. Mike Wall’s book, “Out There” (Grand Central Publishing, 2018 illustrated by Carl Tait) on the discovery of foreign life, is now available. All about space banners More space?

You can get 5 issues from our companion magazine “All About Space” for the latest amazing news from Last Frontier for $ 5!. Join our space forum to chat about the latest missions, the night sky and more! And if you have a news suggestion, correction or comment. A new study analyzed why large and Neptune-sized exoplanets are rare.

A new study analyzed why large and Neptune-sized exoplanets are rare: Sub-Neptunes- extrasolar planets with Ready between 2.7 and 3 times Earth – are much larger than planets the size of Neptune and larger. A new study proposes that this fall is so sudden because the Sub-Neptune atmosphere merges easily with the magma oceans on its surface.

When the planets reach approximately 3 times the size of the Earth. This is a clear advantage in the data, and it is quite dramatic. We are surprised that the planets want to stop growing almost 3 times the size of the Earth, “said Dr. John. A planet scientist at the University of Chicago. Edwin Kight said – it is believed that Sub-Neptune has oceans of magma on its surfaces, which remain warm thanks to a thick layer of hydrogen-rich atmosphere.

Dr. So far, almost all models have ignored this magma, but it is considered chemically inert. But liquid rock flows almost like water and is very reactive, Kight said.Dr. Kight and his colleagues considered the question of whether the ocean could begin to dissolve the atmosphere, because the planets receive more hydrogen. In this scenario, when a sub-Neptune occupies more gas.

It accumulates in the atmosphere and the downward pressure begins to form where magma meets the atmosphere. First, magma raises excess gas at a constant rate, but as pressure increases, hydrogen begins to dissolve in magma much more easily. Not only that, but a little of the additional gas remaining in the atmosphere increases the atmospheric pressure and, therefore. A large fraction of the gas that arrives later will dissolve in magma, said Dr. Cometa explained.

Thus, the growth of the planet stops before it reaches the size of Neptune. The authors of the study call it the “fugitive crisis”, after the word that measures the ease with which a gas dissolves in a mixture as a function of pressure. The theory fits well with existing observations, Dr. Comet mentioned. There are also many markers that astronomers can see in the future.

For example, if the theory is correct, then planets with oceans of magma that are cold enough to crystallize on the surface must show different profiles, because it will prevent the ocean from absorbing so much hydrogen. The study was published in the Astrophysical Journal Letters. The “Superpopular” Exoplanet is nothing like the Solar System In recent years, studies of extrasolar planets have exploded.

Currently, astronomers have been able to confirm the existence of 4,104 planets beyond our solar system. Awaiting confirmation from another 4900. Studies of these many planets have revealed things about the range of possible planets in our universe and have taught us that there are many for which there are no analogues in our solar system.

For example, thanks to the new data obtained by the Hubble Space Telescope. Astronomers have learned more about a new class of exoplanets known as “overpopulated” planets. The planets of this class are basically young gas giants that are comparable in size to Jupiter.

But have masses that are only slightly taller than those on Earth. This causes the density of cotton candy in its atmosphere, hence its cheerful nickname. The only known examples of this planet live in the Kepler 51 system, a young Sun-like star located about 2,615 light years away in the Cygnus planetarium.

Within this system, three exoplanets have been confirmed (Kepler-51B, C and D) that were first detected by the Kepler space telescope in 2012. However. It was not until 2014 that the density of these planets was confirmed, and This was a big surprise.

Three giant planets that orbit the star Kepler 51 similar to the Sun compared to some planets in our solar system. While these gas giants have atmospheres that are formed by hydrogen and helium and are the same size as Jupiter, they are also a hundred times lighter in terms of mass.

How and why their atmospheres would skyrocket remains a mystery, but the fact that the nature of their atmosphere makes the Super Puff planets a leading candidate for atmospheric analysis. This is exactly what an international team of astronomers, led by Jessica Libby-Roberts of the Center for Astrophysics.

And Space Astronomy (CASA) of the University of Colorado, Boulder, tried to do. Using data from Hubble, Libby-Roberts and his team analyzed the spectra obtained from the Kepler-51B atmosphere and to see if the components (including water) were there.

When the planets passed in front of their stars, the light absorbed by their atmosphere was tested in infrared wavelengths. To the team’s surprise, they discovered that the spectra of both planets had no revealing chemical signatures. This was attributed to the presence of salt crystals or photochemical clouds in its atmosphere.

Therefore, the team relied on computer simulations and other devices to say that the Kepler-51 planets are mostly hydrogen and helium, covered with a thick mist made of methane. This is similar to Titan’s movement to the atmosphere of Saturn (Saturn’s largest moon), where there are clouds of methane gas primarily in the nitrogen atmosphere that obscure the surface. It was completely unexpected, Libby-Roberts said.

We had planned to visit large water absorption facilities, but they weren’t there. They forced us out! However, these clouds provided the team with valuable information on how Kepler-51B and D compare with other low-mass gas-rich exoplanets observed by astronomers. As Libby-Roberts stated in a CU Boulder press release.

We knew they were low density. But when you break a cotton ball in the form of Jupiter, it is really low density. It definitely prevents us from coming to visit us. We expected to find water, but we could not observe the signature of any molecule. The team was able to improve the size and mass of these planets by measuring their effects of time.

In all systems, there are slight changes in the planet’s orbit period due to its gravitational attraction, which can be used to obtain the mass of a planet. The team’s results coincided with previous estimates for the Kepler-51B, while estimates for the Kepler-51D indicated that it is a little less massive (also known as more bloated) than before.

The team also compared the spectra of the two superpoletas with other planets and obtained results that indicated that cloud / fog formation is associated with the planet’s temperature. This supports the hypothesis that the planet is colder, it will be the cloud that some astronomers have discovered thanks to recent discoveries of exoplanets.

Mini Neptune planets vary in size from about 1.5 to 4 times the size of the Earth and have a rocky core of varying thickness and a complete gas shell. Geoff Mercy – Last but not least, the team noted that both Kepler-51B and D are losing gas quickly. In fact, the team estimates that the ancient planet (which is closer to its original star) is throwing tens of billions of tons of matter into space every second.

If this trend continues, the planets will be significantly reduced in the next billion years and can become mini-Neptune. In this sense, this would suggest that exoplanets are not so uncommon after all, which makes mini-catches seem very common. It also suggests that super puffs are responsible for the age of the planet’s low density system. While the solar system is about 4.6 billion years old, Kepler-51 dates back to about 500 million years.

The planetary model used by the team suggests the possibility of planets forming beyond the Kepler-51 frost line, the limit beyond which unstable elements freeze and then migrate inward. Instead of heterogeneous planets, then, Kepler-51B and D may be the first examples that astronomers have seen in the initial stage of development of one of the most common types of planets in our universe.

As Zach Berta-Thompson (assistant professor of APS and co-author of the new research) explained. This makes the Kepler-51 a “unique laboratory” to test theories of early planetary evolution: This is an extreme example of what is great about the exoplanet in general. They give us the opportunity to study worlds that are very different from ours.

But place the planets in a broader context in our solar system. Illustration of NASA’s James Webb space telescope: NASA In the future, the deployment of next-generation instruments, such as the James Webb Space Telescope (JWST). Astronomers to investigate the atmosphere of the Kepler-51 planets and other superpoletas.

Thanks to the sensitivity of JWSTs with infrared wavelengths, we can still see their dense clouds and determine what these “cotton candy” planets are made. Scientists say ‘Exomoon’ may be the best place to search for life around giant planets. I write about science and nature, technology and travel, stargazing and eclipses.

This artist’s imprint reflects exomoon candidate Kepler-1625B-I, orbiting the planet. Do planets disturb life? Or is it likely that their moons are compatible with extraterrestrial life forms? According to an astronomer at Lincoln University. The planets that orbit the Moon outside our solar system can give us clues about the world’s pool that can harbor extraterrestrial life.

What moons are we talking about: the so-called “axons” are very difficult. So difficult, in fact, that there are no confirmed exams. Scientists have to find the effect on the objects around them and find them. However, Drs at Lincoln University in the UK. Phil Sutton believes that although some exoplanets live in the so-called ‘habitable zone’.

And some of them, especially the largest gas giant planets the size of Jupiter that have been ignored in the search. Life can, in fact, host moons that contain liquid water. He said: These moons can be heated internally by the gravitational pull of the planet’s orbit, causing liquid water out of the narrow habitable zone common to planets that we currently see on Earth-like planets trying to find, says Sutton.

I think that if we can find them, the moons provide more promising income for finding extraterrestrial life. One such candidate is an exoplanet named J1407B, which is 434 light years from the solar system at the Centaurus planetarium. The artist’s conception of the extrasolar ring system orbiting the young giant planet or brown dwarf J1407b is shown.

The rings are shown dwarfing young Suraj-like star J1407, as they appeared in early 2007. The best-fit model fits a system of at least 30 rings, and there are spaces where satellites can occur (om xDoon ″). It is already formed. The artist’s conception of the extrasolar ring system revolves around the young giant planet or brown dwarf.

The strongest earthquake in Mexico, the tsunami warning issued by Hubble, reveals a ‘red dot wonder’ of the distant universe. What is special about the Exoplanet J1407b? It has rings..big rings Think of Saturn, but 200 times bigger. Looking at the possibility of orbiting J1407b in Sutton’s latest research.

It was analyzed whether they could cause gaps in the planet’s ring system. This is one way to find the Exomoon. Sutton ran computer simulations to model the rings around J1407b, calculated the gravitational forces between all the particles, then added a moon to test whether rings formed.

What happens to Saturn’s rings due to their lunar mimes (the so-called “Cassini division”). The results were inconclusive, but previous research suggests that the J1407b’s massive “moon-forming disk” has many gaps that can be explained by exomoon. The rings around J1407b are so large that they are placed around Saturn.

Some people think Exomoons are not only possible, they are possible. Last year, researchers at the University of California, Riverside and the University of South Queensland published descriptions of 100 giant planets that harbor moons capable of potentially supporting life.

This is a short list for the James Webb Space Telescope (JWST) and other telescopes that will be seen more closely in the coming years. The researchers identified 121 gas giant planets within their stars’ habitable zones, each of which is expected to host several large moons.

There are currently 175 known moons that orbit around eight planets in our solar system. While most of these orbit the Moon and Saturn and Jupiter. Which are outside the Sun’s habitable zone, that may not occur in other solar systems.

And Stephen Kane, associate professor of planetary astrophysics and UCR A member of the Center for Astronomy Earth Alternative said: The inclusion of rocky axons in our search for life in space will greatly expand the places we can see. There are currently no confirmed examples of planetary satellites orbiting the exterior of our solar system.

However, there is evidence that an exomoon named Kepler-1625b-x orbits around the Jupiter-sized gas giant star, Kepler-1625b. Columbia University astronomers Alex Techey and David M. Kipping consider it to be Neptune-shaped. Kepler-1625B in the Cygnus constellation is 8,000 light years from the solar system.


Planet-sized object 8,000 light years away could be the first alien moon ever found

Spotting a planet orbiting a star 8,000 light-years away isn’t exactly easy, but modern telescope technology has allowed astronomers to accomplish such feats with shocking regularity, especially over the past half decade or so. We now know of thousands of planets that exist outside of our Solar System, but we also know from our own system that lots of planets have natural satellites.

Scientists have never had enough evidence to confirm that any exoplanet has a moon orbiting it, but that might be about to change. Kepler-1625b, a massive planet orbiting a not-too-distant star, seems to have a friend along for the ride, and scientists are racing to confirm their findings and declare it the very first alien moon on record.

In a new paper published in Science Advances, Alex Teachey and David Kipping of Columbia University present their case for the first “exomoon,” and it’s some pretty wild stuff.

Scientists are able to detect far-away worlds by measuring the light output of the stars they orbit. When a star’s brightness dips it’s a good indication that something has passed in front of it, and by measuring the light as it wanes it’s possible to estimate the size, distance, and nature of the planet.

Spotting an exomoon is done in largely the same way, and if the team’s measurements are on point we’re looking at an absolutely enormous moon and an even larger host planet.

According to the researchers, the data which was gathered from recent Hubble Space Telescope observations of the star Kepler-1625 shows that the exoplanet Kepler-1625b is several times larger than Jupiter, the largest planet in our Solar System by a mile. Its moon alone is estimated to be roughly the size and mass of Neptune, which has a radius four times that of Earth. Yeah, these are really, really big objects.

We likely won’t have total confirmation of the exomoon’s existence for some time, but advancing telescope technology will eventually allow astronomers to make definitive judgements on observations like this.

Mike Wehner has reported on technology and video games for the past decade, covering breaking news and trends in VR, wearables, smartphones, and future tech.