Author Topic: Dwarf planet discovery hints at a hidden Super Earth in solar system  (Read 105644 times)

Offline Star One

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I don't even have faith now that we haven't overlooked something as massive as a Brown Dwarf comparatively close at hand, closer that is than Proxima Centauri considering how high their population in the galaxy seems to be. Their proposed population numbers seem at odds with the discovery numbers by WISE, which does make you question how effective WISE actually was in this area.

WISE has discovered plenty of near-by, cool dwarfs (brown & red), but indeed nothing closer than Proxima. Even if the WISE observations were incomplete, it would seem strange that it would have overlooked primarily the closest (and thus brightest) objects from these classes.

What makes you think the WISE result is at odds with proposed population numbers? And even if there is a statistically significant discrepancy, shouldn't the actual observation (or non-observation, in that case) be given priority above model-dependent population numbers?

Well does a possible population of 100 billion Brown Dwarfs in the Milky Way seem in line with the WISE observations to you?

Offline Bynaus

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I don't even have faith now that we haven't overlooked something as massive as a Brown Dwarf comparatively close at hand, closer that is than Proxima Centauri considering how high their population in the galaxy seems to be. Their proposed population numbers seem at odds with the discovery numbers by WISE, which does make you question how effective WISE actually was in this area.

WISE has discovered plenty of near-by, cool dwarfs (brown & red), but indeed nothing closer than Proxima. Even if the WISE observations were incomplete, it would seem strange that it would have overlooked primarily the closest (and thus brightest) objects from these classes.

What makes you think the WISE result is at odds with proposed population numbers? And even if there is a statistically significant discrepancy, shouldn't the actual observation (or non-observation, in that case) be given priority above model-dependent population numbers?

Well does a possible population of 100 billion Brown Dwarfs in the Milky Way seem in line with the WISE observations to you?

I guess you are referring to that recent suggestion that the Milky Way might contain between 25 and 100 billion Brown Dwarfs (BDs). Their suggested star / BD ratio is in the region of 2-5. This range is compatible with the WISE results:

If we look at the 10 nearest star systems (plus the sun), there are 13 stars vs. 3 BDs (all discovered by WISE), so the ratio is within the range given above. If we look at the 20 closest systems, there are 28 stars and 6 BDs (3 of which have been discovered by WISE), again a ratio <5. If we go to the 30 closest systems, there are 37 stars and 8 BDs (4 from WISE), again a ratio <5. It is well possible that WISE overlooked a few objects (especially some old, dark BDs), which might drive the true star / BD ratio in the solar neighborhood closer to the center of the estimated range above. On this page, a similar conclusion was reached: WISE results suggest about six stars per BD. While this is lower than earlier figures (which had suggested a star / BD ratio of up to one), it is roughly in agreement with the suggested 25-100 billion BDs in the Milky Way galaxy.

Offline Star One

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I don't even have faith now that we haven't overlooked something as massive as a Brown Dwarf comparatively close at hand, closer that is than Proxima Centauri considering how high their population in the galaxy seems to be. Their proposed population numbers seem at odds with the discovery numbers by WISE, which does make you question how effective WISE actually was in this area.

WISE has discovered plenty of near-by, cool dwarfs (brown & red), but indeed nothing closer than Proxima. Even if the WISE observations were incomplete, it would seem strange that it would have overlooked primarily the closest (and thus brightest) objects from these classes.

What makes you think the WISE result is at odds with proposed population numbers? And even if there is a statistically significant discrepancy, shouldn't the actual observation (or non-observation, in that case) be given priority above model-dependent population numbers?

Well does a possible population of 100 billion Brown Dwarfs in the Milky Way seem in line with the WISE observations to you?

I guess you are referring to that recent suggestion that the Milky Way might contain between 25 and 100 billion Brown Dwarfs (BDs). Their suggested star / BD ratio is in the region of 2-5. This range is compatible with the WISE results:

If we look at the 10 nearest star systems (plus the sun), there are 13 stars vs. 3 BDs (all discovered by WISE), so the ratio is within the range given above. If we look at the 20 closest systems, there are 28 stars and 6 BDs (3 of which have been discovered by WISE), again a ratio <5. If we go to the 30 closest systems, there are 37 stars and 8 BDs (4 from WISE), again a ratio <5. It is well possible that WISE overlooked a few objects (especially some old, dark BDs), which might drive the true star / BD ratio in the solar neighborhood closer to the center of the estimated range above. On this page, a similar conclusion was reached: WISE results suggest about six stars per BD. While this is lower than earlier figures (which had suggested a star / BD ratio of up to one), it is roughly in agreement with the suggested 25-100 billion BDs in the Milky Way galaxy.

Thank you for that. I had read some commentary suggesting the two weren't compatible.

But I should add a caveat here that part of the argument was that BDs may come in much smaller sizes than previously thought and that this may cause an issue with the WISE results.
« Last Edit: 07/13/2017 09:52 PM by Star One »

Offline Star One

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Evidence Mounts for the Existence of Planet Nine

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It seems that the outer Solar System is getting more crowded with every passing year. And these planets, if and when they are confirmed, are likely to trigger another debate about which Solar bodies are rightly designated as planets and which ones aren’t. If you thought the “planetary debate” was controversial and divisive before, I recommend staying away from astronomy forums in the coming years!

https://www.universetoday.com/136450/evidence-mounts-existence-planet-nine/amp/

Offline Dao Angkan

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Evidence Mounts for the Existence of Planet Nine

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It seems that the outer Solar System is getting more crowded with every passing year. And these planets, if and when they are confirmed, are likely to trigger another debate about which Solar bodies are rightly designated as planets and which ones aren’t. If you thought the “planetary debate” was controversial and divisive before, I recommend staying away from astronomy forums in the coming years!

https://www.universetoday.com/136450/evidence-mounts-existence-planet-nine/amp/

If it's that crowded, then how come no Kuiper Belt dwarf planets have been discovered for years, even though many more people have been searching for them since the initial wave were discovered? Anyway, it's just a debate about semantics, which exoplanet discoveries are making largely redundant. What's the point of a definition of a planet which only applies to our own system and not the possibly infinite amount of other systems, or indeed planemos not attached to a system?
« Last Edit: 07/15/2017 08:11 PM by Dao Angkan »

Offline Dao Angkan

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Under the current classification, I think that they would still be considered moons. As I understand it, a body orbiting another body which in turn orbits a star is considered a moon, whether it orbits a planet, dwarf planet, asteroid, KBO, etc.

Personally, I don't care what Pluto and other KBOs are defined as, just that it should apply to all planemos, not just the ones in our own solar system.

As for planet 9/10/X ... it's possible, but we've seen so many different theories on this for so many years, that I take it with a pinch of salt until we see actual evidence.

Edit: This was a response to a post which must have been deleted before I replied.
« Last Edit: 07/15/2017 08:21 PM by Dao Angkan »

Offline CuddlyRocket

Evidence Mounts for the Existence of Planet Nine

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It seems that the outer Solar System is getting more crowded with every passing year. And these planets, if and when they are confirmed, are likely to trigger another debate about which Solar bodies are rightly designated as planets and which ones aren’t. If you thought the “planetary debate” was controversial and divisive before, I recommend staying away from astronomy forums in the coming years!

https://www.universetoday.com/136450/evidence-mounts-existence-planet-nine/amp/

I think that depends on how big they are and where they are. If they're the 'right' side of the line, there'll be hardly a murmur! Which line? Well, Margot's planetary discriminant seems to be favourite at present.

Anyway, it's just a debate about semantics, which exoplanet discoveries are making largely redundant.

It's partly about semantics, but there is a difference between gravitationally dominant bodies in a system and the rest, which exoplanet discoveries doesn't affect.

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What's the point of a definition of a planet which only applies to our own system and not the possibly infinite amount of other systems, or indeed planemos not attached to a system?

I agree that the definition should cover other stellar systems, but it need not cover free-floating planemos.

Offline Star One

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A lengthy update on the hunt for the proposed planet nine, including the fact that investigations have caused its theoretical size to be reduced from ten Earth masses to eight.

Is There a Giant Planet Lurking Beyond Pluto?

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Huge telescopes on Earth have been scanning the skies for months now. Brown and Batygin have been observing on Japan’s Subaru telescope on Mauna Kea—as have veteran minor-planet hunters Chad Trujillo of Northern Arizona University and Scott Sheppard of the Carnegie Institution for Science⁠—to exploit that observatory’s giant mirror (8.2 meters across) and its 3-metric-ton, 870-megapixel camera. Meanwhile other astronomers, both professional and amateur, are digging through archives of images in hopes of finding this needle in a hayfield.

Any of them could get lucky. But the smart money is on software, either to deliver the quarry or reveal it to be an illusion. Simulations running on supercomputers and in the cloud are modeling billions of years of celestial mechanics to pin down Planet Nine’s likeliest path. Engineers at the Jet Propulsion Laboratory, in Pasadena, have been analyzing telemetry from the Cassini spacecraft for clues to the current position of the putative planet within its enormous orbit. And an ambitious pair of graduate students is preparing to deploy machine-learning software on a petaflop-scale Cray XC40 supercomputer. Their strategy aims to cleverly combine multiple images in which Planet Nine is hidden within the noise to yield one image in which it shines unmistakably.

Although many astronomers share Brown’s enthusiasm at the prospect of finding a planet bigger than Earth for the first time in 170 years, some worry about being fooled by subtle biases or simple coincidences in the data. “My instinct—completely unjustifiable—is that there’s a two-thirds chance it’s really there,” Laughlin says.

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Those odds are now steeper because the list of relevant oddball planetoids known to haunt the outer reaches of our solar system has lengthened: from 6 in early 2016 to 20, Trujillo says. About a dozen of these objects orbit within the same vertically tilted plane as Planet Nine does, but they sweep away from the sun in the opposite direction of the planet; a couple of others are aligned with the planet. Then there are a handful of planetoids circling crazily at almost right angles to everything else in the solar system; a couple of these even travel backward around the sun. “They all fit in beautifully,” Batygin says. “As time has gone on, the evidence has only increased.”

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With the idea of a big but undiscovered planet in our cosmic backyard moving from possible to plausible, Planet Nine hunters now have to face their biggest challenge: deciding where to point their telescopes. “We don’t actually know where the planet is today in its orbit,” Batygin says. To narrow the search, his team and other astronomers are sifting clues from computer simulations that recapitulate billion-year segments of the solar system’s past or predict its far future.

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“I’m running 12 integrations of the real objects in the outer solar system and how they would behave over the next billion years with Planet Nine, given different values for the seven parameters,” he says. The combinations of values are guesses, guided mainly by his intuition. “If one ever happens to work”—meaning that the virtual solar system keeps humming along for the next billion years without the new planet wreaking havoc—“I can jump up and down,” he smiles.

It takes his workstation just two days to model the celestial interactions of 200 tracer objects over a billion years, thanks to advances in technology. Moore’s Law has obviously helped. But the early 1990s also brought a big breakthrough in an algorithm, known as symplectic integration, that reduced computational times by an order of magnitude. Then came multicore and massively parallel computing systems, which are ideally suited for what Brown calls “embarrassingly parallel” problems like tracing how the orbits of many objects evolve over a wide range of starting conditions.

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Symplectic integration is so complicated that even Brown admits he doesn’t fully understand the math. “But the key idea,” he explains, “is to take advantage of the fact that you already know that any object circling the sun mostly follows a simple orbit,” as described by Kepler’s laws of planetary motion—plus some minor perturbations. Because symplectic integrators don’t waste time rediscovering Kepler’s laws over and over, they run orbital simulations hundreds of times as fast as older methods do. One of the most popular symplectic modeling platforms is called Mercury (not to be confused with the planet), and it has become the tool of choice for several of the planet-hunting teams, including Brown and Batygin.

At Yale, Laughlin and his graduate student Sarah Millholland enhanced Mercury last autumn with a Markov-chain Monte Carlo algorithm to home in more quickly on promising orbits. Using the 1,000-core supercomputing cluster at Yale, they were able in a month to simulate a total of 1019 years of orbital mechanics, tracking not only 11 extreme trans-Neptunian objects but also uncertainties in their observations.

“We got orbital parameters that agree well with Brown’s and Batygin’s values,” Laughlin says. “But our simulation gives a more precise place in the sky to look for it.” Their paper, published in February, as well as more recent supercomputer simulations presented in April by Trujillo, puts Planet Nine somewhere in the constellation Cetus (the whale) or Eridanus (the river), at about 28 times the current distance to Pluto. “It’s still a vast search area,” Trujillo says.

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Initial results seemed encouraging: Extreme TNO orbits lined up just as others had found. “It showed that Planet Nine could be responsible for that,” Nesvorný says. But things didn’t work out as well when he then focused on how Planet Nine would affect a certain class of comets.

“My model nicely reproduces all orbital parameters for these comets—until I add Planet Nine,” he says. In the model, the new planet tilts the so-called scattered disk, where Jupiter-family comets originate, causing the virtual comets to enter the solar system more steeply than the real ones do.

More caveats to Planet Nine’s theorized existence come from the Cassini probe, which has orbited Saturn since 2004. From minute changes in the spacecraft’s speed and other telemetry, the Cassini team calculates the distance from Earth to Saturn to within 3 meters. Those range measurements could reveal even small deviations in Saturn’s orbit due to the pull from Planet Nine, but only if it is close or large enough. William Folkner, a principal engineer at JPL, says he and coworkers examined the data and saw no perceptible distortion of Saturn’s orbit. So, if Planet Nine exists and is 10 times Earth’s mass, it must be within 25 degrees of the farthest point in its hypothetical orbit, he says. A smaller Planet Nine—Brown now favors a mass eight times that of Earth—would have 40 degrees of wiggle room to hide in.

The results, positive and negative, aid the handful of observers now hunting for Planet Nine on telescopes. In addition to the groups working on Subaru, Sheppard and Trujillo are leading searches in the high desert of Chile, in case the planet is easier to see from the Southern Hemisphere. There, both the 570-megapixel Dark Energy Camera (DECam) on the 4-meter Blanco telescope and the 6.5-meter Magellan telescopes are contributing to the hunt.

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“I actually think we will not discover Planet Nine by scanning the sky,” Brown says. “We could, but I think somebody will find it first in archival data,” from surveys that have already photographed huge swathes of the heavens. After Uranus and Neptune were discovered, astronomers noticed that earlier stargazers had already recorded the two worlds many times but not recognized them for what they were. Now at least four efforts are under way to find a new planet in old photos.

David Gerdes of the University of Michigan has been combing through the archive of DECam’s survey observations to find images of the planet. By coincidence, Brown notes, “our predicted path for the planet goes right through the Dark Energy Survey’s field of view.”

An army of amateurs has jumped into the game as well. In February, Marc Kuchner of NASA’s Goddard Space Flight Center helped launch a crowdsourced effort to compare successive infrared images made by the Wide-field Infrared Survey Explorer space telescope of the same spot in the sky. By July, the project had recruited 40,000 volunteers, who had thoroughly reviewed over 125,000 chunks of space. A southern-sky version, launched in March with data from the Australian SkyMapper telescope, blew through 106,000 search regions in just three days. Laudable as these citizen-science projects are, their odds of success are low because the small telescopes involved typically cannot gather enough light to see something as dim and distant as Planet Nine is thought to be.

Michael Medford and Danny Goldstein, graduate students at the University of California, Berkeley, think they have a solution to that problem. Drawing on hundreds of thousands of images covering the search area for Planet Nine—all shot from 2009 to 2016 using a 1.2-meter telescope in the mountains north of San Diego—their system will combine multiple images in an ingenious way that should brighten the faint flickers of light from Planet Nine enough to distinguish them from background noise.

“Because the planet is moving with respect to the background stars, you can’t just add overlapping images together,” Medford points out. Instead, their software selects each of the many distinct plausible orbits for Planet Nine, projects the planet’s movement onto the relevant patch of sky, and then offsets successive images to superimpose—and brighten—any pixels corresponding to the planet. A pipeline of software written with Peter Nugent, their faculty advisor, performs the overlapping and subtracts known objects such as stars.

The computational task is enormous because the planet’s orbit is still so uncertain. To do a 98 percent complete search, Medford estimates, they will need to perform 10 billion image comparisons. Fortunately, Nugent has time allocated on the Cori supercomputer, a new Cray XC40 system that recently ranked as the fifth most powerful in the world.

http://spectrum.ieee.org/aerospace/satellites/is-there-a-giant-planet-lurking-beyond-pluto.amp.html
« Last Edit: 08/01/2017 07:33 PM by Star One »

Offline Star One

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Konstantin Batygin @kbatygin
Was #PlanetNine captured in the Sun's natal star-forming region? (link: https://arxiv.org/pdf/1709.00418.pdf) arxiv.org/pdf/1709.00418… [spoiler alert: nah...]

Offline Star One

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Mike Brown has updated on when he begins the hunt again for Planet Nine.

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Mike Brown @plutokiller
Replying to @leosutic
thanks; off to the telescope in 2 weeks!

https://mobile.twitter.com/plutokiller/status/905464596403691521

Offline Star One

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Some tweets regarding Aaron Meisner's search for planet nine. Apparently they have candidates but no final result.

https://mobile.twitter.com/KarinaVoggel/status/90620221071065088

Planet 9 Probably Isn’t an Exoplanet, After All

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Scientists thought Planet 9 might be an exoplanet captured by the Sun in its early days, but new mathematical applications have proven that the likelihood of planet-swapping for the potential new solar sister is near zero. This raises the question: how could the big planet have gotten so far out there?

https://futurism.com/planet-9-probably-isnt-an-exoplanet-after-all/
« Last Edit: 09/08/2017 07:25 PM by Star One »

Offline Bynaus

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Ha, interesting, about the candidates. Watch that space, I guess.

Offline Star One

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Ha, interesting, about the candidates. Watch that space, I guess.

It made me laugh when Mike Brown pretended he knew nothing about it.

Online Alpha_Centauri

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I'm one of the ones searching the Neowise data with Aaron and others.  I've not heard anything concrete; frankly i doubt it will have been found yet, even in the best case scenario from Fortney et al. (2016) it would be at the edge of detectability and with really unhelpful motion between the epochs in-hand. There is new reprocessed Neowise data coming soon which will make finding it a little easier though.
« Last Edit: 09/08/2017 09:02 PM by Alpha_Centauri »

Offline Star One

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I'm one of the ones searching the Neowise data with Aaron and others.  I've not heard anything concrete; frankly i doubt it will have been found yet, even in the best case scenario from Fortney et al. (2016) it would be at the edge of detectability and with really unhelpful motion between the epochs in-hand. There is new reprocessed Neowise data coming soon which will make finding it a little easier though.

But would you have heard anything though as I'd of thought something like this they would keep under their hats until they were ready to say something definitive.

Online Alpha_Centauri

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Yeah that's true, even good brown dwarf finds are kept quiet, though we find out sooner rather than later.  I'm just saying if one of us has found it then kudos to them because it really is tough.
« Last Edit: 09/08/2017 10:09 PM by Alpha_Centauri »

Offline CuddlyRocket

Some tweets regarding Aaron Meisner's search for planet nine. Apparently they have candidates but no final result.

https://mobile.twitter.com/KarinaVoggel/status/90620221071065088

"Sorry, that page doesn't exist!" Interesting. (Of course, there's many possible explanations - but I like the 'premature disclosure' one best! :) )

Offline Star One

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Some tweets regarding Aaron Meisner's search for planet nine. Apparently they have candidates but no final result.

https://mobile.twitter.com/KarinaVoggel/status/90620221071065088

"Sorry, that page doesn't exist!" Interesting. (Of course, there's many possible explanations - but I like the 'premature disclosure' one best! :) )

Try this instead.

https://mobile.twitter.com/plutokiller/status/906205915325513728

Judging by what happened to that tweet it looks like they do want to keep things under their hats.
« Last Edit: 09/08/2017 11:45 PM by Star One »

Offline Star One

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Quote
Safir @safirjamil
·
22h
@plutokiller As the P9 search is about to resume, is the process boring? How about vlogging it? Or live stream maybe? QnA to pass time.

Mike Brown @plutokiller
Replying to @safirjamil
a week from today.
stay tuned.
11:56 pm · 12 Sep 2017

https://mobile.twitter.com/plutokiller/status/907739846780764160

Offline Star One

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I am feeling a bit sorry for Mike Brown at the moment as thanks to this guy called David Meade he keeps being asked questions about this lunacy of planet nine crashing into Earth on his Twitter feed by people who seem genuinely frightened. It must be galling for him as this Meade character has tied his wagon onto Brown's genuine work.

He actually has had this pinned to the top of his Twitter feed since July.

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Mike Brown @plutokiller
Weekly PSA: no, in fact the earth is NOT going to be destroyed by [fill in crazy thing seen on internet here] next week. Thanks for asking.
6:02 pm · 21 Jul 2016

https://mobile.twitter.com/plutokiller/status/756172592348737541
« Last Edit: 09/17/2017 11:40 AM by Star One »

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