Author Topic: Dwarf planet discovery hints at a hidden Super Earth in solar system  (Read 296856 times)

Offline meekGee

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Would you trust a denial from the guy who killed Pluto?
ABCD - Always Be Counting Down

Offline Star One

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Would you trust a denial from the guy who killed Pluto?

Somebody recently asked him on there if he was after Mercury next!!!

Offline meekGee

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Would you trust a denial from the guy who killed Pluto?

Somebody recently asked him on there if he was after Mercury next!!!

Funny...

And I would respond to the idea, but I know where this would lead...
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Offline jgoldader

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Would you trust a denial from the guy who killed Pluto?

Somebody recently asked him on there if he was after Mercury next!!!

Funny...

And I would respond to the idea, but I know where this would lead...

Another committee...    ::)
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Offline Star One

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The hunt for planet nine is rejoined with this major update from Mike Brown.

Quote
We haven’t found Planet Nine yet, in case you were wondering.  To date, the telescopic searches have really just begun to scratch the surface of the area that needs to be scanned, and, while clever new projects to find Planet Nine with different techniques have been proposed, most of these efforts are just getting underway. But don’t worry: the new season of Subaru searching starts tonight! With good weather, we should be able to scan a significant part of our search area. Stay tuned.


To get ready for this new season of searching for Planet Nine, we have spent most of the last year developing our understanding of the way that Planet Nine interacts with the rest of the solar system. Much of this has involved large amounts of analytic and computational work to figure out what the orbit of Planet Nine looks like and where in its orbit Planet Nine is. If we could figure that out perfectly, we could simply go out tonight and point our telescopes right at it, as was done for the discovery of Neptune in 1846. Sadly, we have less information on Planet Nine than Le Verrier did for Neptune in 1846, so we’re not able to pinpoint it just yet, but we are able to constrain what the orbit looks like and, thus, where we should look.

http://www.findplanetnine.com/2017/09/planet-nine-where-are-you-part-1.html?m=1
« Last Edit: 09/21/2017 08:30 pm by Star One »

Offline Star One

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Can I ask Mike Brown says he is observing through to next Tuesday, it’s clear he’s not the only one out there so would he have a team of people with him and will that team have exclusive use of the telescope looking for planet nine until then?
« Last Edit: 09/23/2017 07:55 pm by Star One »

Offline Bynaus

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From the Twitter feed it seems like Konstantin Batygin is with him. Not sure how long an individual session on Subaru would be, i.e., if you would have exclusive access the whole time or not.
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Offline Star One

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From the Twitter feed it seems like Konstantin Batygin is with him. Not sure how long an individual session on Subaru would be, i.e., if you would have exclusive access the whole time or not.

Do you think it’s unusual for him to be out there as someone suggested?

Offline Bynaus

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Its a bit unusual perhaps because Batygin (as I understand it) is a computational astronomer, not an observer as Brown. In other words, someone who works with computers, not telescopes. But I guess he just wanted to take part in the fun this time!
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Offline hop

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A newly discovered, relatively bright, very likely dwarf planet:

A dwarf planet class object in the 21:5 resonance with Neptune
Quote
We report the discovery of a Hr=3.4±0.1 dwarf planet candidate by the Pan-STARRS Outer Solar System Survey. 2010 JO179 is red with (g−r)=0.88±0.21, roughly round, and slowly rotating, with a period of 30.6 hr. Estimates of its albedo imply a diameter of 600--900~km. Observations sampling the span between 2005--2016 provide an exceptionally well-determined orbit for 2010 JO179, with a semi-major axis of 78.307±0.009 au, distant orbits known to this precision are rare. We find that 2010 JO179 librates securely within the 21:5 mean-motion resonance with Neptune on hundred-megayear time scales, joining the small but growing set of known distant dwarf planets on metastable resonant orbits. These imply a substantial trans-Neptunian population that shifts between stability in high-order resonances, the detached population, and the eroding population of the scattering disk.

Michele Bannister (one of the coauthors) tweeted some background
https://twitter.com/astrokiwi/status/910158216675373056
Quote
Q. Any part of the #planetnine story?
A. No. 2010 JO179's a=78.3 au orbit is close, compared to what a distant giant planet would influence.

Offline redliox

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A newly discovered, relatively bright, very likely dwarf planet:

A dwarf planet class object in the 21:5 resonance with Neptune
Quote
We report the discovery of a Hr=3.4±0.1 dwarf planet candidate by the Pan-STARRS Outer Solar System Survey. 2010 JO179 is red with (g−r)=0.88±0.21, roughly round, and slowly rotating, with a period of 30.6 hr. Estimates of its albedo imply a diameter of 600--900~km. Observations sampling the span between 2005--2016 provide an exceptionally well-determined orbit for 2010 JO179, with a semi-major axis of 78.307±0.009 au, distant orbits known to this precision are rare. We find that 2010 JO179 librates securely within the 21:5 mean-motion resonance with Neptune on hundred-megayear time scales, joining the small but growing set of known distant dwarf planets on metastable resonant orbits. These imply a substantial trans-Neptunian population that shifts between stability in high-order resonances, the detached population, and the eroding population of the scattering disk.

Michele Bannister (one of the coauthors) tweeted some background
https://twitter.com/astrokiwi/status/910158216675373056
Quote
Q. Any part of the #planetnine story?
A. No. 2010 JO179's a=78.3 au orbit is close, compared to what a distant giant planet would influence.

Impressive.  The upper range of the diameter (which naturally is uncertain for now) would make it comparable to Ceres, and certainly worthy of 'dwarf' status.  I doubt we'll actually find a new giant planet (gas or ice), but certainly we could find more worlds like these including perhaps those kin to Pluto and Eris' size and perhaps evidence that'd support the theory of a 5th giant that was ejected.
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Offline Star One

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A newly discovered, relatively bright, very likely dwarf planet:

A dwarf planet class object in the 21:5 resonance with Neptune
Quote
We report the discovery of a Hr=3.4±0.1 dwarf planet candidate by the Pan-STARRS Outer Solar System Survey. 2010 JO179 is red with (g−r)=0.88±0.21, roughly round, and slowly rotating, with a period of 30.6 hr. Estimates of its albedo imply a diameter of 600--900~km. Observations sampling the span between 2005--2016 provide an exceptionally well-determined orbit for 2010 JO179, with a semi-major axis of 78.307±0.009 au, distant orbits known to this precision are rare. We find that 2010 JO179 librates securely within the 21:5 mean-motion resonance with Neptune on hundred-megayear time scales, joining the small but growing set of known distant dwarf planets on metastable resonant orbits. These imply a substantial trans-Neptunian population that shifts between stability in high-order resonances, the detached population, and the eroding population of the scattering disk.

Michele Bannister (one of the coauthors) tweeted some background
https://twitter.com/astrokiwi/status/910158216675373056
Quote
Q. Any part of the #planetnine story?
A. No. 2010 JO179's a=78.3 au orbit is close, compared to what a distant giant planet would influence.

Impressive.  The upper range of the diameter (which naturally is uncertain for now) would make it comparable to Ceres, and certainly worthy of 'dwarf' status.  I doubt we'll actually find a new giant planet (gas or ice), but certainly we could find more worlds like these including perhaps those kin to Pluto and Eris' size and perhaps evidence that'd support the theory of a 5th giant that was ejected.

Why do you doubt we’ll find a new giant planet? I’d say the evidence at the moment is against you. It would also be nice to prove cynics wrong especially as nature time and time again has proved our pre-existing assumptions wrong in multiple fields of scientific endeavour.

I think the reason our Solar System looks the way it does is because in the way that the TNOs are controlled by Neptune or the asteroid belt is maintained by Jupiter. That the further out objects are controlled by another ice giant. Also that the Keiper belt looks the way it does is because there is true planetary sized object within it. To maintain these kind of effects requires a persistent presence and is unlikely to be explained by transitory things such as passing stars.
« Last Edit: 09/24/2017 03:05 pm by Star One »

Offline Bynaus

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Since the pattern of orbital alignments (of those many "scattered disk" objects) would disappear within a few 10 Ma without P9 (i.e., if it had been ejected early on), chances are it is still out there somewhere.

If anyone would ask for reasons to doubt the existence of P9, I'd rather point to articles like this one:

https://arxiv.org/abs/1706.07447

Quote
Origin and Evolution of Short-Period Comets

D. Nesvorný et al., 2017

Comets are icy objects that orbitally evolve from the trans-Neptunian region (the Kuiper belt and beyond) into the inner Solar System, where they are heated by solar radiation and become active due to sublimation of water ice. Here we perform end-to-end simulations in which cometary reservoirs are formed in the early Solar System and evolved over 4.5 Gyr. The gravitational effects of Planet 9 (P9), hypothesized to circle the Sun on a wide orbit, are included in some of our simulations. Different models are considered for comets to be active, including a simple assumption that comets remain active for Np(q) perihelion passages with perihelion distance q<2.5 au. The orbital distribution and number of active comets produced in our model is compared to observations. The orbital distribution of ecliptic comets (ECs) is well reproduced in models with Np(2.5)=500 and without P9. With P9, the inclination distribution of model ECs is wider than the observed one. We find that the known Halley-type comets (HTCs) have a nearly isotropic inclination distribution (with only a slight preference for prograde orbits). In our model, the HTCs appear to be an extension of the population of returning Oort-cloud comets (OCCs) to shorter orbital periods. The inclination distribution of model HTCs becomes broader with increasing Np, but the existing observational data are not good enough to constrain Np from orbital fits. Np(2.5)>1000 is required to obtain a steady-state population of large active HTCs that is consistent with observations. To fit the ratio of the returning-to-new OCCs, by contrast, our model implies that Np(2.5)<10, possibly because the detected long-period comets are smaller and much easier to disrupt than observed HTCs.

EDIT: PS: And yes, I also think that we will continue to find dwarf planets in the Kuiper belt for decades to come. Every new generation of telescopes will reveal additional populations. I think its a good bet that there will be many large objects in the Oort cloud, perhaps up to Mars size or more (as this is the typical size of the planetary embryos, of which many had to be ejected early on as the gas giants formed).
« Last Edit: 09/24/2017 04:36 pm by Bynaus »
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Offline Star One

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Since the pattern of orbital alignments (of those many "scattered disk" objects) would disappear within a few 10 Ma without P9 (i.e., if it had been ejected early on), chances are it is still out there somewhere.

If anyone would ask for reasons to doubt the existence of P9, I'd rather point to articles like this one:

https://arxiv.org/abs/1706.07447

Quote
Origin and Evolution of Short-Period Comets

D. Nesvorný et al., 2017

Comets are icy objects that orbitally evolve from the trans-Neptunian region (the Kuiper belt and beyond) into the inner Solar System, where they are heated by solar radiation and become active due to sublimation of water ice. Here we perform end-to-end simulations in which cometary reservoirs are formed in the early Solar System and evolved over 4.5 Gyr. The gravitational effects of Planet 9 (P9), hypothesized to circle the Sun on a wide orbit, are included in some of our simulations. Different models are considered for comets to be active, including a simple assumption that comets remain active for Np(q) perihelion passages with perihelion distance q<2.5 au. The orbital distribution and number of active comets produced in our model is compared to observations. The orbital distribution of ecliptic comets (ECs) is well reproduced in models with Np(2.5)=500 and without P9. With P9, the inclination distribution of model ECs is wider than the observed one. We find that the known Halley-type comets (HTCs) have a nearly isotropic inclination distribution (with only a slight preference for prograde orbits). In our model, the HTCs appear to be an extension of the population of returning Oort-cloud comets (OCCs) to shorter orbital periods. The inclination distribution of model HTCs becomes broader with increasing Np, but the existing observational data are not good enough to constrain Np from orbital fits. Np(2.5)>1000 is required to obtain a steady-state population of large active HTCs that is consistent with observations. To fit the ratio of the returning-to-new OCCs, by contrast, our model implies that Np(2.5)<10, possibly because the detected long-period comets are smaller and much easier to disrupt than observed HTCs.

EDIT: PS: And yes, I also think that we will continue to find dwarf planets in the Kuiper belt for decades to come. Every new generation of telescopes will reveal additional populations. I think its a good bet that there will be many large objects in the Oort cloud, perhaps up to Mars size or more (as this is the typical size of the planetary embryos, of which many had to be ejected early on as the gas giants formed).

The reason I think there is a larger body in there is that the whole Keiper belt is twisted out of alignment I believe and the most likely way to do that is with a body of considerable mass.

Offline Star One

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Quote
Mike Brown @plutokiller
Night 4 of Subaru Planet Nine search on Maunakea. We're slowly vacuuming up the sky. My blood O2 level is low, but caffeine level is peaking

https://mobile.twitter.com/plutokiller/status/912282530329407488

Offline Ben the Space Brit

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One of the great pending discoveries in genetic engineering will be to give professionals the ability to subsist only on strong coffee instead of oxygen and any nutrients.
« Last Edit: 09/25/2017 12:29 pm by Ben the Space Brit »
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Offline Star One

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Various tweets from Mike Brown concerning the search for planet nine.

https://mobile.twitter.com/plutokiller/status/912284298996178944

Quote
Mike Brown @plutokiller
Curious where we were looking for Planet Nine last night? Here's the view straight down the Subaru telescope barrel. #NameThatConstellation

https://mobile.twitter.com/plutokiller/status/912391716363227137
« Last Edit: 09/25/2017 08:19 pm by Star One »

Offline Star One

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Mike Brown @plutokiller
Night 5 (of 5) of the Subaru Planet Nine search on Maunakea now underway. Another beautiful night. Tomorrow: home to play with data!

https://mobile.twitter.com/plutokiller/status/912637604402569216

Quote
Konstantin Batygin @kbatygin
Between observing runs we hiked up to lake Waiau at 13000ft. @plutokiller got so excited his head fell off. Back on now. P9 search continues

https://mobile.twitter.com/kbatygin/status/912480583002996736

Offline Star One

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Quote
Mike Brown
Mike Brown @plutokiller
Telescope now shuts down for ~2 months of routine maintenance then we're back in December to resume the search. Stay tuned.

https://mobile.twitter.com/plutokiller/status/912685408722358278

I assume the environment degrades it but how often do they have do this?

Quote
Mike Brown @plutokiller
(I know 2 months is a long time, but they have to periodically remove the entire mirror from the telescope and realuminize it. Big job.)

https://mobile.twitter.com/plutokiller/status/912687846711992321
« Last Edit: 09/26/2017 08:02 pm by Star One »

Offline as58

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I assume the environment degrades it but how often do they have do this?

I believe that the last time was in 2013 after the mirror was damaged in camera coolant leak. Recoating every few years is typical also in other major observatories. Two months does sound like quite a long stop for just recoating, so maybe they're doing some other maintenance, too.

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