Alpha Centauri 2

Community => Recreation Commons => Destination: Alpha Centauri => Topic started by: Buster's Uncle on July 27, 2025, 02:50:39 pm

Title: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on July 27, 2025, 02:50:39 pm

Astronomers discover new dwarf planet 'Ammonite' — and it could upend the existence of Planet Nine
Elana Spivack
Live Science (https://www.livescience.com/)
Thu, July 24, 2025 at 4:09 PM EDT


(https://s.yimg.com/ny/api/res/1.2/8eTjeCy1m6TIDHUinnBrQg--/YXBwaWQ9aGlnaGxhbmRlcjt3PTk2MDtoPTU0MDtjZj13ZWJw/https://media.zenfs.com/en/live_science_953/36951035d6c96680434151f9643d62c1)
The orbit of the newly detected dwarf planet ‘Ammonite’ (2023 KQ14, shown in red) compared to the orbits of the other three known sednoids (in white). | Credit: NAOJ


Astronomers have discovered a possible new dwarf planet orbiting far beyond Pluto. First detected in March 2023 by Japan's Subaru Telescope in Hawaii, this object has been dubbed 2023 KQ14 and nicknamed Ammonite. Ammonite's appearance also puts a kink in what's known as the Planet Nine hypothesis, which suggests there may be an undiscovered ninth planet in our solar system.

Led by researchers in Japan, the team announced Ammonite's discovery in a paper published July 14 in the journal Nature Astronomy (https://go.redirectingat.com/?id=92X1590019&xcust=livescienceyahoo_us_3672327979356117722&xs=1&url=https%3A%2F%2Fwww.nature.com%2Farticles%2Fs41550-025-02595-7&sref=&uuid=hsO2q8IIvagmw2w12443). The body gets its moniker from the fossil of a long-extinct cephalopod because it was identified as part of the survey project Formation of the Outer Solar System: An Icy Legacy, or FOSSIL.

Ammonite is classified as a sednoid, which is an object beyond Neptune — our solar system's outermost confirmed planet — with a peculiar orbit. It's now the fourth sednoid discovered. The term "sednoid" comes from the dwarf planet Sedna, which exists at our solar system's edge and was discovered in 2004.

When describing the orbits of celestial bodies, astronomers use astronomical units (AU). The distance between Earth and the sun is approximately 1 AU. Following an elliptical path, Sedna is about 76 AU from the sun at its nearest point (perihelion) and 900 AU at its farthest (aphelion). Ammonite, meanwhile, is between 66 and 252 AU from the sun at the closest and farthest points in its orbit.

The discovery of 2023 KQ14 detracts from the possibility that there could be a ninth planet for our solar system, according to the study authors. First proposed in 2016, the Planet Nine hypothesis suggests there may be a Neptune-size planet orbiting the sun about 20 to 30 times farther from the sun than Neptune is.

This planet would explain the eccentric orbits of smaller bodies in the Kuiper Belt, which is the vast expanse of icy rocks that encompasses the outer solar system. It's believed that the gravity of a much more massive body, like a planet, may be shepherding these smaller objects. However, the relationship between the newest sednoid's orbit and that of the other three known sednoids calls this hypothesis into question.

"The planet 9 hypothesis is based on the fact that the known Sednoids have their orbit cluster on one side of the solar system," study co-author Shiang-Yu Wang, a research fellow at the Institute of Astronomy and Astrophysics in Taiwan, told Live Science in an email.

Ammonite is unique among these sednoids because its orbit is on the opposite side — its furthest point from the sun is in the opposite direction from the other sednoids' furthest points. The fact that there is now a known object orbiting on this path decreases the possibility that a large planet could be out there, too.

"The fact that 2023 KQ14's current orbit does not align with those of the other three sednoids lowers the likelihood of the Planet Nine hypothesis," study co-author Yukun Huang, a project research fellow at the National Astronomical Observatory of Japan's Center for Computational Astrophysics, said in a press release (https://www.nao.ac.jp/en/news/science/2025/20250715-subaru.html). "It is possible that a planet once existed in the Solar System but was later ejected, causing the unusual orbits we see today."

Other astronomers also believe Ammonite throws a wrench in this hypothesis. "The trouble is the evidence from the alignment has never been scientifically convincing and hasn't really grown stronger, even over the last 10 years or so," David Jewitt, a professor of astronomy at the University of California, Los Angeles who was not involved in Ammonite's discovery, told Live Science.

"Ammonite does not align with these six other objects, so weakens the case for Planet Nine, or means it must be very remote and correspondingly difficult to detect," Christopher Impey, an astronomy professor at the University of Arizona who was not involved in the sednoid's discovery, told Live Science.

But Impey is confident that, if there really is a Planet Nine, the newly activated Vera C. Rubin Observatory in Chile will soon be able to confirm it. "If Planet Nine exists, it will almost certainly be found in that survey data within a few years," he said.

https://www.yahoo.com/news/articles/astronomers-discover-dwarf-planet-ammonite-200935551.html

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Geo on July 27, 2025, 06:05:40 pm

Another headache for Mike Brown's Ninth Planet hypothesis...

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on July 27, 2025, 06:23:17 pm

I'm not real fond of the ninth planet stuff, Pluto having deserved to be grandfathered in and all.

Tenth planet?  I guess it would be way cool if they found something huge out there...

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Geo on July 27, 2025, 07:45:43 pm

If there's something outthere on the mass Brown&alligned allege, its going to be a slightly smaller icebag like Neptune or Uranus.
The highlight of the day would be an Earth-sized rocky planet. Formation models of how the Solar System came to be will have to be re-examined then.

On Pluto not being a planet anymore as decided by the IAU, that decision has historical precedent. Back in the early 19th century the newly discovered objects Ceres, Juno, Pallas, and Vesta were considered planets too.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on July 27, 2025, 08:05:13 pm

I believe none of those Victorian discoveries lasted ANYthing like 90 years before being demoted, which is a real difference.  I'll fight on the Pluto hill, not least for being bigger than all those you mentioned combined.  It IS, isn't it?

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Geo on July 27, 2025, 08:28:20 pm

Quote from: Buster's Uncle on July 27, 2025, 08:05:13 pm

I believe none of those Victorian discoveries lasted ANYthing like 90 years before being demoted, which is a real difference.  I'll fight on the Pluto hill, not least for being bigger than all those you mentioned combined.  It IS, isn't it?

You have a point there (for 7 decades anyway). But Clyde Tombaugh's discovery was more of an accident. It just happened to be in a predicted position by an even earlier astronomist (Percival Lowell) who presumed a planet IX like Neptune and Uranus. If Lovell hadn't made that prediction, I doubt Pluto would've been discovered for another couple decades at least.
I think most of the people fighting the Pluto hill are a sort of patriots, defending what they perceive to be an American scientific hegemony in space. ;no
And while Pluto might be a sliver bigger, there's at least one known more massive dwarf planet out there (Eris).

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on July 27, 2025, 08:31:50 pm

I'm being a nerd who doesn't accept change easily, though there's regard for Tombaugh mixed in, none of it's conscious nationalism.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Geo on July 27, 2025, 08:40:57 pm

If you're interested in reading more about those early 19th century discoveries, I suggest this (https://en.wikipedia.org/wiki/Ceres_(dwarf_planet)#Classification) Wikipedia article.
It looks like the classification of those early-discovered 'planets' lasted about half a century. ;nod

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on July 27, 2025, 08:48:08 pm

I can't get my back up about change way before my time...

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Geo on July 27, 2025, 09:26:30 pm

Quote from: Buster's Uncle on July 27, 2025, 08:48:08 pm

I can't get my back up about change way before my time...

Pluto was found way before your time.
In fact, Pluto's moon, Charon, wasn't discovered before you discovered girrrrrls. ;cute

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on July 27, 2025, 09:29:38 pm

Yeah, but Pluto's MINE -in a way some asteroids and/or trans-neptunians can never be- and how dare they take it away.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Lorizael on July 31, 2025, 11:59:41 pm

There are 5 planets: Mercury, Venus, Mars, Jupiter, and Saturn

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on August 01, 2025, 12:15:41 am

I wanted to ask you if you had a gold nose, but that was Brahe, not Copernicus...

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Lorizael on August 01, 2025, 12:36:40 am

Every culture in history, for thousands of years, recognized that there were only 5 planets, until a British colonizer spotted a big weird ice ball out there and named it after his king.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on August 01, 2025, 12:39:31 am

Wasn't that a George?

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Lorizael on August 01, 2025, 12:40:00 am

#3

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on August 01, 2025, 12:45:34 am

Popular fellow, even there.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Geo on August 01, 2025, 06:53:26 am

Quote from: Lorizael on August 01, 2025, 12:36:40 am

Every culture in history, for thousands of years, recognized that there were only 5 planets, until a British colonizer spotted a big weird ice ball out there and named it after his king.

Herschel is not an English name...  ;cute

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Lorizael on August 01, 2025, 01:50:45 pm

Neither is Hanover or Saxe-Coburg, but what can you do.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on August 01, 2025, 02:51:07 pm

Bow to our Germanic masters...

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Lord Avalon on August 01, 2025, 11:11:18 pm

If Pluto is a planet, then surely you would include Eris. While smaller in diameter, it is more massive than Pluto.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on August 01, 2025, 11:15:35 pm

One is an old friend -maybe family- the other is a stranger I do not know to love.

I'm comfortable on this hill.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Lord Avalon on August 01, 2025, 11:18:59 pm

That ain't science.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on August 01, 2025, 11:21:41 pm

I guess maybe not, but I'm still comfortable on this hill.  Pluto should have been grandfathered in, not that bothering to finally define what a planet IS was otherwise a bad thing.  The lack of a definition was sloppy and unscientific.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Lorizael on August 02, 2025, 01:21:08 am

I'm... just going to paste bits of something I wrote years ago when Alan Stern (PI of the New Horizons mission) got an OpEd in the Post about how his ball should be a planet.

Historically, for thousands of years, planets were defined entirely by their orbital characteristics and not even a little bit by their physical properties. If we still want to use the word planet today in a scientific sense, we can either (a) hew to their historical (orbital) origins, or (b) divorce ourselves from that notion and ground our definition in something a little more rigorously physical and scientific.

If we want a scientific notion of planet, what we're looking for is a term that is explanatorily useful. In the protoplanetary disk, are different physical processes responsible for creating different hunks of matter (accretion versus collapse)? In mature solar systems, do we see geographically distinct regions (main best asteroids versus trojans)? If there are such rough divisions, then distinct taxonomic categories become useful. We can say that zirbadube-type objects formed via mejazolistic-like processes and ended up in the squanomok region. Without taxonomies, we're required to be reductive. Then a question like "how did the solar system form?" can only be answered with "physics."

Of course, this sounds eminently reasonable, and people like Stern and Grinspoon would probably say that's what they're doing. And maybe they are. But the claim that it's obviously correct for historical, common sense, and scientific reasons that Pluto is a planet and that others are necessarily being dictatorial or unscientific is... well... hyperbolic. The solar system is a much bigger and weirder place than we imagined it to be even a few decades ago. We should have lively discussions about how it all fits together. But there's no reason to frame this as a battle over the rank and status of one very cool ball of ice and rock in the Kuiper belt.

For planetary scientists, I think planet is probably too general a term to be all that useful. Terrestrial planets, gas giants, and ice giants all seem very different except for being spherical non-stars. In the Planetary Data System, there are separate nodes for atmospheres, geosciences, cartography and imaging sciences, planetary plasma interactions, ring-moon systems, and small bodies. Titan, which the authors call out as being a "planet moon," has datasets in almost all of these nodes depending on mission parameters. To my mind, planetary scientists don't need a definition. They all know they're studying big rocky icy gassy things in the solar system. They're much more likely to have a fight about the technical differences between, like, meteorite subtypes.

For astronomy more broadly, however, I think the historical conception has value. Planets are wanderers--the objects that stick out from the surrounding stars. They're the features by which we characterize a solar system. Oh, that system has 3 hot Jupiters. That one has an Earth twin. From that standpoint, we only care about the big, round bodies that play a role in the dynamics of the system. Something like Pluto is one of our many kuiper belt objects--cool and worth studying--but not one of the defining features of the solar system.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on August 02, 2025, 01:28:10 am

The defining feature of our solar system is the star, well north of 99% of it.  The rest is niggling detail.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Lorizael on August 02, 2025, 03:33:06 am

And yet the rest of the planets are gravitationally significant if you want to understand the structure and evolution of the solar system.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on August 02, 2025, 03:38:23 am

Those leftover specks?

Give me back Pluto, and you can have your dirt.

---

Note:  I'm actually semi-serious.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Geo on August 02, 2025, 07:20:28 am

Quote from: Buster's Uncle on August 02, 2025, 03:38:23 am

Those leftover specks?

Give me back Pluto, and you can have your dirt.

---

Note:  I'm actually semi-serious.

You still have Pluto. It just has a nomer in front of it, like Earth is a "rocky" planet, Jupiter a "gas" planet, so is Pluto (and Ceres, and Eris,...) a "dwarf" planet.

Title: Re: Astronomers discover new dwarf planet 'Ammonite'
Post by: Buster's Uncle on August 02, 2025, 01:16:50 pm

It's like Star Trek, only backwards.