Author Topic: Dwarf planet discovery hints at a hidden Super Earth in solar system  (Read 135501 times)

Offline Alpha_Centauri

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I happen to be one of the ones doing the Kuchner et al. search with Aaron's co-adds, that's why I'm just trying to add some realism.  I'd love to find it but seeing the data we would have to be very lucky.

Found plenty of probably "nearby" cold brown dwarfs though. Sorry, no P9 yet. 
« Last Edit: 12/15/2017 07:38 PM by Alpha_Centauri »

Offline Star One

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Quote
Mike Brown
@plutokiller

21 Jan
As of yesterday(!) we now have statistically rigorous calculations of best fit orbit and mass of P9 and, critically, uncertainties on all of these parameters. Along with that comes a rigorous calculation of a probability that that is no P9: 0.01%

Quote
Mike Brown
@plutokiller

21 Jan
So this is all great news for the search. The less great news? The area that we need to search remains pretty big. It will still take some time. We're back to the telescope in a couple of weeks, and will keep at it until it's found.

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Mike Brown
@plutokiller

21 Jan
(papers with all of the details coming soon[ish] to an arXiv near you)

https://mobile.twitter.com/plutokiller/status/955099713308475392
« Last Edit: 01/22/2018 08:13 PM by Star One »

Offline TakeOff

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Wasn't planet Nine dismissed after precision measurements of the Solar System's barycenter recently? Using pulsars and Cassini's location of Saturn to within 100 meters or so. A massive planet out there would've been noticed.
« Last Edit: 01/24/2018 05:58 PM by TakeOff »

Online hop

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Wasn't planet Nine dismissed after precision measurements of the Solar System's barycenter recently? Using pulsars and Cassini's location of Saturn to within 100 meters or so. A massive planet out there would've been noticed.
Nope. If there were a really convincing negative conclusion, people wouldn't still be using lots of precious telescope time to look for it.

There was some back and forth over the Cassini results some time ago, but nothing close to definitive.

Offline Alpha_Centauri

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There was a brief mention of such a finding (specifically it is about pulsar timing, not Cassini) which was to be written up, though both Brown and Batygin commented they were sceptical the results would be able to say much about the existence of Planet Nine as it is essentially static wrt the solar system barycenter; however to my knowledge no such paper has yet to be published to be able to comment on either way.
« Last Edit: 01/25/2018 01:26 AM by Alpha_Centauri »

Offline Star One

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Wasn't planet Nine dismissed after precision measurements of the Solar System's barycenter recently? Using pulsars and Cassini's location of Saturn to within 100 meters or so. A massive planet out there would've been noticed.
Nope. If there were a really convincing negative conclusion, people wouldn't still be using lots of precious telescope time to look for it.

There was some back and forth over the Cassini results some time ago, but nothing close to definitive.

Considering how much telescope time Brown appears to have been clocking up in the last few months with more to come soon it sounds at least as far as heís concerned that heís not buying their conclusions.
« Last Edit: 01/25/2018 06:23 AM by Star One »

Offline Star One

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I didnít know high winds could smear out images like this for a professional scope.

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Mike Brown
@plutokiller
Night 2 on Mauna Kea and it is still clear and beautiful with the Magellanic Clouds just peeking over the southern horizons and the Milky Way blazing overhead. But, sadly, the high winds are turning the stars into pancakes in my images. I like pancakes. But not this many pancakes

https://mobile.twitter.com/plutokiller/status/962204876875821056

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Mike Brown
@plutokiller
One more night like tonight and my hopes for finding Planet Nine this season fade to zero. But I guess it is time start working up my optimism for next winter.

https://mobile.twitter.com/plutokiller/status/962205325775454208
« Last Edit: 02/10/2018 08:28 PM by Star One »

Offline Ben the Space Brit

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I didnít know high winds could smear out images like this for a professional scope.

It makes sense that extremely high sustained movement of the atmosphere would have optical effects that would be difficult to filter out without impacting on the accuracy of data on extremely faint near-point sources.
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Offline jgoldader

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I didnít know high winds could smear out images like this for a professional scope.

I wish I'd held onto some of the stuff we got back in the day so I could show you.  Wind shake produced smeared stars, like a whole bunch of hyphens (or sometimes slashes, even shaped like an upper-case L on occasion), and when the seeing was going really bad, your image went from the hoped-for near diffraction-limited sharpness to horrible blobs 5+ arc-seconds wide, with the PSF never looking the same twice.  You'd wonder if you weren't looking through clouds, because if you spread faint starlight over enough pixels, you can't really see the stars.
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Offline as58

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I didnít know high winds could smear out images like this for a professional scope.

I'm not sure which instrument Brown is using, but it's very likely something without adaptive optics. AO only works well over a small field of view (thought it's improving with multi-conjugate systems), so survey telescopes don't have them.

And even when using an instrument with AO, seeing still matters. There's limits to what AO can do, so the best data is obtained in good seeing conditions.

Offline Star One

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I didnít know high winds could smear out images like this for a professional scope.

I'm not sure which instrument Brown is using, but it's very likely something without adaptive optics. AO only works well over a small field of view (thought it's improving with multi-conjugate systems), so survey telescopes don't have them.

And even when using an instrument with AO, seeing still matters. There's limits to what AO can do, so the best data is obtained in good seeing conditions.

Heís using the Subaru Telescope out in Hawaii.

Offline mikelepage

I guess for this super earth [its Hill sphere] would be absurdly larger? Has there been any discussion of how this could affect the sort of moon system it could have?

According to Wikipedia the radius of a planet's Hill sphere is approximately a x (1-e) x cube root of m/3M, where a is the semi-major axis, e the orbital eccentricity, m the planet mass and M the mass of the Sun. For Planet Nine, a is approx 25 times that of Neptune; 1-e approximately 0.4 times and the cube root of m approximately 0.8 times. This gives a Hill radius approximately eight times that of Neptune (930 million kilometers - 6.2 AU! - versus 116 million kilometers).

As for the effect on any moon system, it would mean that a much more expansive moon system would be possible (Neptune's furthest moon (Neso) is at 50 million kilometers). However, it would seem likely that any initial moons would have been lost in the process of Planet Nine attaining its present orbit and the chances of it meeting, let alone capturing, any objects would be very low!

Shoemaker-Levy 9 was shredded through a previous interaction with Jupiter before it finally crashed.  I wonder if it's not a bit premature to say any initial moons would definitely have been "lost" by the ejection event.

Hard to say with any certainty until we find it, but perhaps any such moons could have been kept (although tidally disrupted) through the event that ejected planet nine.  Perhaps we'll find an extensive ring system, or (my fanciful hope) a large liquid water "ocean moon" in an orbit conducive to tidal heating.

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