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 Post subject: Re: Do we have 9 planets again?Posted: Fri Sep 09, 2016 12:58 pm
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Joined: Sun Nov 13, 2011 4:39 pm
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Location: Gilford Park
Just published in The Astronomical Journal, but it's still available on arXiv.

Observational Constraints on Planet Nine: Astrometry of Pluto and Other Trans-Neptunian Objects

https://arxiv.org/abs/1603.09008

Quote:
We use astrometry of Pluto and other TNOs to constrain the sky location, distance, and mass of the possible additional planet (Planet Nine) hypothesized by Batygin and Brown (2016). We find that over broad regions of the sky, the inclusion of a massive, distant planet degrades the fits to the observations. However, in other regions, the fits are significantly improved by the addition of such a planet. Our best fits suggest a planet that is either more massive or closer than argued for by Batygin and Brown (2016) based on the orbital distribution of distant trans-neptunian objects (or by Fienga et al. (2016) based on range measured to the Cassini spacecraft). The trend to favor larger and closer perturbing planets is driven by the residuals to the astrometry of Pluto, remeasured from photographic plates using modern stellar catalogs (Buie and Folkner 2015), which show a clear trend in declination, over the course of two decades, that drive a preference for large perturbations. Although this trend may be the result of systematic errors of unknown origin in the observations, a possible resolution is that the declination trend may be due to perturbations from a body, additional to Planet Nine , that is closer to Pluto, but less massive than, Planet Nine.

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 Post subject: Re: Do we have 9 planets again?Posted: Wed Sep 14, 2016 5:42 pm

Joined: Thu Oct 13, 2011 12:53 pm
Posts: 251
For those preoccupied with a ninth planet, they'll actually be looking for it soon as described in this post by Andrew Lowe to the Minor Planet Mailing List...

Quote:

http://www.latimes.com/opinion/op-ed/la ... story.html

According to the article, the two Caltech astronomers have six nights booked on the Subaru telescope.

Planet Nine is expected to be near aphelion. For a bit of fun, let's assume that the preferred orbit from their June 2016 ApJ. article is correct, so that the mean anomaly=180 degrees, a=700 A.U., e=0.6, inclination=30 degrees, argument of perihelion=150 degrees, and ascending node=87.57 degrees, to obtain their ecliptic longitude of perihelion=241 degrees.

Five of the six anti-aligned distant Kuiper belt objects (KBOs) that they used for their analysis are near perihelion (2010 GB174 passed perihelion in 1951 and is further to the west). Consequently, these KBOs are close to the expected position of Planet Nine, some 20 degrees east of Orion (and in the article, Brown actually mentions that the search area will be close to Orion).

Here is a display, courtesy of SkyMap, showing Planet Nine's nominal position and the five KBOs:

http://members.shaw.ca/andrewlowe/planetnine.jpg

Of course, given the actual uncertainty in all of Planet Nine's elements, and its faintness at V=25, the search is going to be a challenge; the last comments in the article are great:

Batygin: Neptune was found on the very first night of its observational search, so that's what we're hoping for.
Brown: Yeah -- I don't think we're that good.

Andrew
http://members.shaw.ca/andrewlowe/home.htm

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Joe Stieber
http://sjastro.org/

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 Post subject: Re: Do we have 9 planets again?Posted: Wed Sep 14, 2016 10:26 pm
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Joined: Sun Nov 13, 2011 4:39 pm
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Thanks, Joe!

Wrote this up for The Daily Grail and gave you credit too.

http://dailygrail.com/2016/9/The-Hunt-P ... e-is-Afoot

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 Post subject: Re: Do we have 9 planets again?Posted: Thu Sep 15, 2016 3:15 pm

Joined: Thu Oct 13, 2011 12:53 pm
Posts: 251
You're welcome Chris, but all I did was copy a post from Andrew Lowe on the Minor Planet Mailing List. Rather than me, you should credit the MPML, and more so, Andrew Lowe, especially for the chart he prepared.

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 Post subject: Re: Do we have 9 planets again?Posted: Thu Sep 15, 2016 4:54 pm
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Joined: Sun Nov 13, 2011 4:39 pm
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AL is credited as a source in the article.

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 Post subject: Re: Do we have 9 planets again?Posted: Fri Sep 16, 2016 10:35 am

Joined: Thu Oct 13, 2011 12:53 pm
Posts: 251
AL is credited as a source in the article.

Chris,

I just looked at the Daily Grail article again and didn't see Andrew Lowe or the Minor Planet Mailing List mentioned, so I ran a text search on the page for each individual word of the six words in AL and MPML, and the only hit was "planet" with nine matches, including one in the comment section.

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 Post subject: Re: Do we have 9 planets again?Posted: Tue Oct 11, 2016 1:13 am

Joined: Thu Oct 13, 2011 12:53 pm
Posts: 251
This post hit the Minor Planet Mailing List at 1:16 am EDT on October 11, 2016. The author is a credible poster.

Quote:
Surely this will hit the news later today or tomorrow, but for fair warning, 2014 UZ224 was announced only an hour ago as another distant TNO: This one blows the others out of the water, however. Its current distance is around 90.8 AU, second only to Eris's 96.2.

Furthermore, it's a definite member of the planet Nine group, and now the second largest known after Sedna, with an absolute magnitude of 3.5, furthermore making it the largest object discovered since 2013 FY27 in 2013! This asteroid sets many records, and hopefully will set many more as it travels closer to the Sun, and more importantly, more recovery observations are made of it.

~Sam

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Joe Stieber
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 Post subject: Re: Do we have 9 planets again?Posted: Tue Oct 11, 2016 7:00 am
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Joined: Sun Nov 13, 2011 4:39 pm
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Cool, Joe!

A Friend For Pluto: Astronomers Find New Dwarf Planet In Our Solar System

http://www.npr.org/sections/thetwo-way/ ... lar-system

https://en.wikipedia.org/wiki/2014_UZ224

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 Post subject: Re: Do we have 9 planets again?Posted: Wed Oct 12, 2016 10:38 am
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More on 2014 UZ224, courtesy of Scientific American.

New Dwarf Planet Found in Our Solar System

https://www.scientificamerican.com/arti ... ar-system/

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 Post subject: Re: Do we have 9 planets again?Posted: Thu Oct 20, 2016 3:58 pm
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Joined: Sun Nov 13, 2011 4:39 pm
Posts: 1884
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New Work on Planet Nine

http://www.centauri-dreams.org/?p=36522

Quote:
The duo are working with graduate student Elizabeth Bailey, lead author of a new study being discussed at the American Astronomical Society’s Division for Planetary Sciences meeting in Pasadena, which is occurring in conjunction with the European Planetary Science Congress. The new paper is all about angles and alignments, focusing on the fact that the relatively flat orbital plane of the planets is tilted about six degrees with respect to the Sun. That’s an oddity, and Planet Nine, hypothesized to be about ten times the mass of the Earth and in an orbit averaging 20 times Neptune’s distance from the Sun, just may be the cause.

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 Post subject: Re: Do we have 9 planets again?Posted: Tue Oct 25, 2016 6:38 am
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Closing in on a Giant Ghost Planet

https://www.scientificamerican.com/arti ... st-planet/

Quote:
Batygin and Brown's work narrowed down the planet’s possible mass and orbit to areas where previous observations might have missed it. Their calculations suggest that it has a mass between five to 20 times that of Earth—a figure that is key to knowing the approximate size of the object they are looking for. They also suggest that its orbit is likely tilted about 30 degrees compared to the plane of the solar system—the relatively thin, flat zone in which the eight major planets orbit. They also propose that the planet is now likely near its farthest point from the sun, in the sky's northern hemisphere, and that it likely has an elongated orbit averaging between 380 and 980 astronomical units (AU) from the sun. (One AU is the average distance between Earth and the sun.)

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 Post subject: Re: Do we have 9 planets again?Posted: Wed Dec 07, 2016 9:52 am
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Joined: Sun Nov 13, 2011 4:39 pm
Posts: 1884
Location: Gilford Park
New Extreme Trans-Neptunian Objects: Toward A Super-Earth in the Outer Solar System

http://iopscience.iop.org/article/10.38 ... ld.iop.org

Quote:
We are performing a wide and deep survey for extreme distant solar system objects. Our goal is to understand the high-perihelion objects Sedna and 2012 VP113 and determine if an unknown massive planet exists in the outer solar system. The discovery of new extreme objects from our survey of some 1080 square degrees of sky to over 24th magnitude in the r-band are reported. Two of the new objects, 2014 SR349 and 2013 FT28, are extreme detached trans-Neptunian objects, which have semimajor axes greater than 150 au and perihelia well beyond Neptune (q > 40 au). Both new objects have orbits with arguments of perihelia within the range of the clustering of this angle seen in the other known extreme objects. One of these objects, 2014 SR349, has a longitude of perihelion similar to the other extreme objects, but 2013 FT28 is about 180° away or anti-aligned in its longitude of perihelion. We also discovered the first outer Oort Cloud object with a perihelion beyond Neptune, 2014 FE72. We discuss these and other interesting objects discovered in our ongoing survey. All the high semimajor axis (a > 150 au) and high-perihelion (q > 35 au) bodies follow the previously identified argument of perihelion clustering as first reported and explained as being from an unknown massive planet in 2014 by Trujillo & Sheppard, which some have called Planet X or Planet Nine. With the discovery of 2013 FT28 on the opposite side of the sky, we now report that the argument of perihelion is significantly correlated with the longitude of perihelion and orbit pole angles for extreme objects and find there are two distinct extreme clusterings anti-aligned with each other. This previously unnoticed correlation is further evidence of an unknown massive planet on a distant eccentric inclined orbit, as extreme eccentric objects with perihelia on opposite sides of the sky (180° longitude of perihelion differences) would approach the inclined planet at opposite points in their orbits, thus making the extreme objects prefer to stay away from opposite ecliptic latitudes to avoid the planet (i.e., opposite argument of perihelia or orbit pole angles).

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 Post subject: Re: Do we have 9 planets again?Posted: Wed Dec 07, 2016 10:00 am
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Joined: Sun Nov 13, 2011 4:39 pm
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Here's the preprint from arXiv:

https://arxiv.org/abs/1608.08772

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 Post subject: Re: Do we have 9 planets again?Posted: Thu Feb 02, 2017 5:55 pm
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Joined: Sun Nov 13, 2011 4:39 pm
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Location: Gilford Park
Constraints on Planet Nine's Orbit and Sky Position within a Framework of Mean-motion Resonances

http://iopscience.iop.org/article/10.38 ... ld.iop.org

Quote:
A number of authors have proposed that the statistically significant orbital alignment of the most distant Kuiper Belt Objects (KBOs) is evidence of an as-yet undetected planet in the outer solar system, now referred to colloquially as "Planet Nine." Dynamical simulations by Batygin & Brown have provided constraints on the range of the planet's possible orbits and sky locations. We extend these investigations by exploring the suggestion of Malhotra et al. that Planet Nine is in small integer ratio mean-motion resonances (MMRs) with several of the most distant KBOs. We show that the observed KBO semimajor axes present a set of commensurabilities with an unseen planet at ~654 au (P ~ 16,725 years) that has a greater than 98% chance of stemming from a sequence of MMRs rather than from a random distribution. We describe and implement a Monte-Carlo optimization scheme that drives billion-year dynamical integrations of the outer solar system to pinpoint the orbital properties of perturbers that are capable of maintaining the KBOs' apsidal alignment. This optimization exercise suggests that the unseen planet is most consistently represented with mass, m ~ 6–12 M ?, semimajor axis, a ~ 654 au, eccentricity, e ~ 0.45, inclination, i ~ 30°, argument of periastron, ? ~ 150°, longitude of ascending node, ? ~ 50°, and mean anomaly, M ~ 180°. A range of sky locations relative to this fiducial ephemeris are possible. We find that the region 30° lesssim R.A. lesssim 50°, ?20° lesssim decl. lesssim 20° is promising.

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 Post subject: Re: Do we have 9 planets again?Posted: Thu Feb 16, 2017 3:46 pm
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Joined: Sun Nov 13, 2011 4:39 pm
Posts: 1884
Location: Gilford Park
Help look for Planet 9!

https://www.zooniverse.org/projects/mar ... 9/classify

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 Post subject: Re: Do we have 9 planets again?Posted: Tue Feb 21, 2017 6:11 pm
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Joined: Sun Nov 13, 2011 4:39 pm
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New Data About Two Distant Asteroids Give a Clue to the Possible 'Planet Nine'

http://www.astrowatch.net/2017/02/new-d ... roids.html

Quote:
Now, a team of researchers led by the Instituto de Astrofísica de Canarias (IAC) in collaboration with the Complutense University of Madrid has taken a step towards the physical characterization of these bodies, and to confirm or refute the hypothesis of Planet Nine by studying them. The scientists have made the first spectroscopic observations of 2004 VN112 and 2013 RF98, both of them particularly interesting dynamically because their orbits are almost identical and the poles of the orbits are separated by a very small angle. This suggest a common origin, and their present-day orbits could be the result of a past interaction with the hypothetical Planet Nine. This study, recently published in Monthly Notices of the Royal Astronomical Society, suggests that this pair of ETNOs was a binary asteroid which separated after an encounter with a planet beyond the orbit of Pluto.

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 Post subject: Re: Do we have 9 planets again?Posted: Mon Apr 03, 2017 7:44 pm
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Astronomers Have Officially Found a Candidate for Planet Nine

Arrogant prick Mike Brown's baby might very well exist, as Guy Consolmagno suggested to Ro back in January.

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 Post subject: Re: Do we have 9 planets again?Posted: Thu Jun 22, 2017 12:11 pm
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Weird orbits hint ‘Planet Ten’ might lurk at solar system edge

https://www.newscientist.com/article/mg ... stem-edge/

So we're swallowing Brown and Batygin's hypothesis of Planet Nine without directly observing the object?

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 Post subject: Re: Do we have 9 planets again?Posted: Fri Jun 23, 2017 7:11 am
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Solar System Survey Casts Doubt on Mysterious “Planet Nine”

https://www.scientificamerican.com/arti ... ine-rdquo/

Quote:
The OSSOS team argues that the biases could have led to false indications of clustering. “They were building this entire argument around six objects with unknown biases in how they were detected,” says astronomer Samantha Lawler at the National Research Council Canada in Victoria, “which is a very dangerous game to play.”

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 Post subject: Re: Do we have 9 planets again?Posted: Thu Jul 13, 2017 3:02 pm
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New Evidence in Support of the Planet Nine Hypothesis

http://www.astrowatch.net/2017/07/new-e ... -nine.html

Quote:
Now, however, two astronomers from the Complutense University of Madrid have applied a new technique, less exposed to observational bias, to study a special type of trans-Neptunian objects: the extreme ones (ETNOs, located at average distances greater than 150 AU and that never cross Neptune's orbit). For the first time, the distances from their nodes to the Sun have been analysed, and the results, published in the journal ‘MNRAS: Letters’, once again indicate that there is a planet beyond Pluto.

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 Post subject: Re: Do we have 9 planets again?Posted: Mon Oct 30, 2017 7:18 am
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Then vs. Now: How the Debate Over a Distant Planet in the Solar System Has Evolved

http://www.planetary.org/blogs/guest-bl ... story.html

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 Post subject: Re: Do we have 9 planets again?Posted: Thu Nov 16, 2017 9:34 am
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Dynamical Evolution Induced by Planet Nine

http://iopscience.iop.org/article/10.38 ... a937c/meta

Quote:

The observational census of trans-Neptunian objects with semimajor axes greater than $\sim 250\,\mathrm{au}$ exhibits unexpected orbital structure that is most readily attributed to gravitational perturbations induced by a yet-undetected, massive planet. Although the capacity of this planet to (i) reproduce the observed clustering of distant orbits in physical space, (ii) facilitate the dynamical detachment of their perihelia from Neptune, and (iii) excite a population of long-period centaurs to extreme inclinations is well-established through numerical experiments, a coherent theoretical description of the dynamical mechanisms responsible for these effects remains elusive. In this work, we characterize the dynamical processes at play from semi-analytic grounds. We begin by considering a purely secular model of orbital evolution induced by Planet Nine and show that it is at odds with the ensuing stability of distant objects. Instead, the long-term survival of the clustered population of long-period Kuiper Belt objects (KBOs) is enabled by a web of mean-motion resonances driven by Planet Nine. Then, by taking a compact-form approach to perturbation theory, we show that it is the secular dynamics embedded within these resonances that regulate the orbital confinement and perihelion detachment of distant KBOs. Finally, we demonstrate that the onset of large-amplitude oscillations of the orbital inclinations is accomplished through the capture of low-inclination objects into a high-order secular resonance, and we identify the specific harmonic that drives the evolution. In light of the developed qualitative understanding of the governing dynamics, we offer an updated interpretation of the current observational data set within the broader theoretical framework of the Planet Nine hypothesis.

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 Post subject: Re: Do we have 9 planets again?Posted: Sun Mar 04, 2018 9:25 am
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Posts: 1884
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High winds prevented discovery of Planet Nine yet

https://www.grenzwissenschaft-aktuell.d ... t20180227/

Quote:
“The winds were so high that atmospheric turbulence rendered the images nearly unusable. We are in the process of analyzing the data, just to be sure, but I do not expect much to come out of them.”

Excuses, excuses.

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 Post subject: Re: Do we have 9 planets again?Posted: Thu Mar 22, 2018 6:08 pm
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Joined: Sun Nov 13, 2011 4:39 pm
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Looking for Planet Nine, Astronomers Gaze into the Abyss

https://www.scientificamerican.com/arti ... the-abyss/

Quote:
Two years on, the search for our solar system’s missing world is as frenzied as ever—and the putative planet is running out of places to hide.

IMO, a quixotic fool's errand. Mike Brown will be remembered as Urbain Le Verrier and his Planet Vulcan.

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 Post subject: Re: Do we have 9 planets again?Posted: Wed May 09, 2018 6:10 pm
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When Is A Planet A Planet?

http://blogs.discovermagazine.com/d-bri ... et-pulsar/

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