The Solar System has a new most-distant member, bringing its outer frontier into focus. New work reports the discovery of a distant dwarf planet, called 2012 VP113, which was found beyond the known edge of the Solar System. This is likely one of thousands of distant objects that are thought to form the so-called inner Oort cloud.
The work indicates the potential presence of an enormous planet, not yet seen, but possibly influencing the orbit of inner Oort cloud objects.
"What!!?? i tought it was official that there wasn't any nemesis"
What's more, their work indicates the potential presence of an enormous planet, perhaps up to 10 times the size of Earth, not yet seen, but possibly influencing the orbit of 2012 VP113, as well as other inner Oort cloud objects.
Their findings are published March 27 in Nature.
From the amount of sky searched, Sheppard and Trujillo determine that about 900 objects with orbits like Sedna and 2012 VP113 and sizes larger than 1000 km may exist and that the total population of the inner Oort cloud is likely bigger than that of the Kuiper Belt and main asteroid belt.
"Some of these inner Oort cloud objects could rival the size of Mars or even Earth. This is because many of the inner Oort cloud objects are so distant that even very large ones would be too faint to detect with current technology," says Sheppard.
" I tought we could detect planet the size of the earth from light years away. Well! the story continue "(Nemesis: to be or not to be)
NASA press release on 7 March 2014...This recent study, which involved an examination of WISE data covering the entire sky in infrared light, found no object the size of Saturn or larger exists out to a distance of 10,000 astronomical units (au), and no object larger than Jupiter exists out to 26,000 au...
...What's more, their work indicates the potential presence of an enormous planet, perhaps up to 10 times the size of Earth, not yet seen, but possibly influencing the orbit of 2012 VP113, as well as other inner Oort cloud objects. ...
The mass of Saturn is 95 times that of Earth at least, according to Fraser Cain. And what is suggested in this new paper is a planet up to 10 times the size of the Earth.
So the two findings are not actually in contradiction. I think...
Margarita
Re: Solar System has a new most-distant member
Posted: Wed Mar 26, 2014 9:47 pm
by geckzilla
No, they're certainly not at odds with one another. The words "giant/enormous planet" are thrown around so casually that you would think the WISE survey conclusion and this discovery are contradicting each other completely.
And, yes, as you said, geckzilla, words like "giant", "enormous", and so on are used so loosely that it is confusing.
In the article I've linked above, the Guardian wrote:
Earlier this month, Nasa's Wide-Field Infrared Survey Explorer (Wise) reported the results from its search for "Planet X", a hypothesised planet far out in the solar system. It found no evidence for a new planet larger than Saturn within 10,000 AU of the sun. But Saturn is 95 times more massive than Earth, so a smaller Super Earth could go undetected in that region.
Trans-Neptunian object: Biden Sedna
---------------------------------------------------
Inclination 24.01° 11.927°
Argument of perihelion 294.4° 311.02°
Perihelion 80.64 AU 76.361 AU
Aphelion 446.1 AU 937 AU
Dimensions 475±160km 995±80km
Absolute magnitude(H) 4.1 1.83
http://en.wikipedia.org/wiki/Gaia_%28spacecraft%29 wrote:
<<Gaia is an unmanned space observatory of the European Space Agency (ESA) designed for astrometry. The mission aims to compile a 3D space catalogue of approximately 1 billion astronomical objects (approximately 1% of the Milky Way population) brighter than 20 G magnitudes, where G is the Gaia magnitude passband between about 400 and 1000 nanometres light wavelengths. Gaia slowly spins with a period of six hours, Gaia's two telescopes would observe simultaneously two rectangular patches of the sky that are separated by an angle of 106.5 degrees (; i.e., the same rectangular patch of the sky separated by 106.5 minutes in time).>>
http://en.wikipedia.org/wiki/2012_VP113 wrote:
<<2012 VP113 (a.k.a, Biden) is a detached trans-Neptunian object. Its discovery was announced on 26 March 2014. It has an absolute magnitude (H) of 4.1, which makes it likely to be a dwarf planet. [Biden] has the largest perihelion of any object in the Solar system. The last perihelion was around 1979, at a distance of 80 AU and is currently 83 AU from the Sun. [Biden] is possibly a member of the hypothesized inner Oort cloud.>>
http://en.wikipedia.org/wiki/90377_Sedna wrote:
<<Sedna has the longest orbital period of any known large object in the Solar System, calculated at around 11,400 years. Its orbit is extremely eccentric, with an aphelion estimated at 937 AU and a perihelion at about 76 AU, the most distant perihelion observed for any Solar System object until the discovery of 2012 VP113. At its discovery it was 89.6 AU from the Sun approaching perihelion, and was the most distant object in the Solar System yet observed. Eris was later detected by the same survey at 97 AU. Although the orbits of some long-period comets extend farther than that of Sedna, they are too dim to be discovered except when approaching perihelion in the inner Solar System. Even as Sedna nears its perihelion in mid 2076, the Sun would appear merely as an extremely bright (star-like) pinpoint in its sky, 100 times brighter than a full moon on Earth (for comparison, the Sun appears from Earth to be roughly 400,000 times brighter than the full Moon), and too far away to be visible as a disc to the naked eye.>>
Re: Solar System has a new most-distant member
Posted: Thu Mar 27, 2014 2:09 pm
by Doum
The mass of Saturn is 95 times that of Earth at least, according to Fraser Cain. And what is suggested in this new paper is a planet up to 10 times the size of the Earth.
So the two findings are not actually in contradiction. I think...
Margarita[/quote]
My misundestood. Thanks for the clarifying. It can still send comet toward the sun. So, if its a nemesis planet it's a smaller one.
Odd, how they withheld all information until the press conference in Brazil.
Totally standard. The information was embargoed until the publication date defined by Nature. The press conference was timed to coincide with the expiration of the publication embargo.
Re: Solar System has a new most-distant member
Posted: Sat Mar 29, 2014 12:19 am
by Psnarf
I knew of the Ort Cloud, what I learned in this article is that the cloud orbits the Sun. How? I kind-of thought they were relatively stationary objects gravity-bound to the Sun. Does each object in the Ort Clout have a different orbit; parabolic or circular? What paths do they take? One graphic I came across showed the Cloud to be spherical, not at all like the Kuiper Belt, like a snow bubble that broke apart into snowballs. It's the only nearby stuff that is not close to the ecliptic formed by the Sun's equator. http://www.reuters.com/article/2014/03/ ... 8S20140326
To make matters weirder, dark matter does not interact with photons, yet it warps space-time as if it was a gravitational attractor. I must have slipped into the other side of the Looking Glass. Things are getting weirder and weirder.
Re: Solar System has a new most-distant member
Posted: Sat Mar 29, 2014 12:28 am
by neufer
Click to play embedded YouTube video.
Re: Solar System has a new most-distant member
Posted: Sat Mar 29, 2014 12:42 am
by Chris Peterson
Psnarf wrote:I knew of the Ort Cloud, what I learned in this article is that the cloud orbits the Sun. How? I kind-of thought they were relatively stationary objects gravity-bound to the Sun.
That would be impossible. Any object stationary with respect to the Sun would simply fall into it. Every stable body in the Solar System in in orbit.
Does each object in the Ort Clout have a different orbit; parabolic or circular?
Yes. Every body is in an elliptical orbit, just as Keplerian dynamics require.
What paths do they take? One graphic I came across showed the Cloud to be spherical...
A spherical cloud just means a random distribution of inclinations.
Other examples of essentially spherical structures, made up of independently orbiting bodies with random inclinations: elliptical galaxies, globular clusters, the bulge of spiral galaxies, the dark matter halo around all galaxies.
To make matters weirder, dark matter does not interact with photons, yet it warps space-time as if it was a gravitational attractor.
What's weird about that? We already have particles that have a finite rest mass and extremely weak interaction with the electromagnetic force, such as neutrinos.
Re: Solar System has a new most-distant member
Posted: Sat Mar 29, 2014 1:30 am
by Nitpicker
MargaritaMc wrote:The mass of Saturn is 95 times that of Earth at least, according to Fraser Cain. And what is suggested in this new paper is a planet up to 10 times the size of the Earth.
So the two findings are not actually in contradiction. I think...
Margarita
Size and mass are different things. A planet 10 times the size of Earth would be a little smaller than Jupiter, and bigger than Saturn. But I think this article is trying to suggest a possible planet of maybe 10 times the mass of Earth.
Re: Solar System has a new most-distant member
Posted: Sat Mar 29, 2014 5:27 am
by Ann
Nitpicker wrote:
MargaritaMc wrote:The mass of Saturn is 95 times that of Earth at least, according to Fraser Cain. And what is suggested in this new paper is a planet up to 10 times the size of the Earth.
So the two findings are not actually in contradiction. I think...
Margarita
Size and mass are different things. A planet 10 times the size of Earth would be a little smaller than Jupiter, and bigger than Saturn. But I think this article is trying to suggest a possible planet of maybe 10 times the mass of Earth.
Very interesting, Nitpicker.
Fascinatingly, brown dwarfs are typically about the size of Jupiter. Perhaps it takes some hydrogen fusion to "inflate" a body considerably more massive than Jupiter.
But is it likely that a planet ten times the mass of the Earth would be nearly the size of Jupiter?
Neptune is the smallest of the four giant outer planets. The diameter at its equator is about 30,775 miles (49,528 kilometers), as measured at a level of the atmosphere where the pressure is 1 bar (the pressure at sea level on Earth). This makes it slightly smaller than Uranus but nearly four times as big as Earth. Neptune's mass is about 1.2 times greater than Uranus', however, and more than 17 times greater than Earth's.
So Neptune is about 17 times as massive as the Earth, and about four times bigger than our planet. (The Britannica text must refer to the diameter of Neptune versus the diameter of the Earth, because the "cloudtop area" of Neptune would be much more than four times the surface area of the Earth, and the difference in volume would be much greater still.)
At seventeen times the mass of the Earth, Neptune is not that far removed from a planet ten times the mass of the Earth. But Neptune is much smaller than Jupiter:
Jupiter’s mass is 318 times that of Earth’s and around 2.5 times that of the rest of the Solar System combined. Jupiter may be the most massive planet in our Solar System, but it would need another 50-80 times its current mass in order to begin fusing its hydrogen into helium and become a star. The planet’s diameter is 11.2 times larger than Earth’s. Jupiter’s volume is 1321 times larger than Earth’s and it’s surface area is 122 times that of Earth’s.
Thebiggest planet in the Universe (at the time of this writing) is TrES-4, which is located 1,400 light years away in the constellation Hercules. The planet has been measured to be 1.4 times the size of Jupiter, but it only has 0.84 times Jupiter’s mass. With such a low density, the media was calling TrES-4 the puffy planet.
How big can a rocky planet be? This is what the Universe Today page answers:
What’s the largest possible rocky planet? For this I put in an email to Dr. Sean Raymond, a post doctoral researcher at the Center for Astrophysics and Space Astronomy (CASA) at the University of Colorado. Here’s what he had to say:
“The largest “terrestrial” planet is generally considered the one before you get too thick of an atmosphere, which happens at about 5-10 Earth masses (something like 2 Earth radii). Those planets are more Earth-like than Neptune-like.”
Ann
Re: Solar System has a new most-distant member
Posted: Sat Mar 29, 2014 3:42 pm
by MargaritaMc
Nitpicker wrote:
Size and mass are different things. A planet 10 times the size of Earth would be a little smaller than Jupiter, and bigger than Saturn. But I think this article is trying to suggest a possible planet of maybe 10 times the mass of Earth.
As was noted here, there is an unhelpful lack of exactitude in reference to "size", and both the NASA news release about the WISE survey and the recent Carnegie Institution press release use the general and undefined term "size" .
As the Guardian article referenced above makes clear, with regards to the orbits of Sedna and 2012 VP113, the issue is that they may be being subjected to a gravitational pull of an unseen body. We are therefore clearly considering mass and not other possible measurements of "size".
Nitpicker, I am intrigued by your saying that "A planet 10 times the size of Earth would be a little smaller than Jupiter, and bigger than Saturn". Presumably, you there using "size" to imply "diameter/circumference"?
Below are comparisons between Saturn/Earth and Jupiter/ Earth indicating the varied ways that the "size" of a planet can be measured.
• Mass…Jupiter has a mass of 1.8981 x 1027 kg. That is over 317 times the mass of Earth.
• Volume…Jupiter’s volume is1.43128 x 1015 km3. That is 1,321 times Earth’s volume.
• Surface area…The surface area of Jupiter is 6.1419 x 1010 km2. Earth is over 120 times smaller.
• Mean circumference…Jupiter has a mean circumference of of 4.39264 x 105 km, which is nearly 11 times larger than Earth’s.
Re: Solar System has a new most-distant member
Posted: Sat Mar 29, 2014 9:56 pm
by Nitpicker
MargaritaMc wrote:
Nitpicker, I am intrigued by your saying that "A planet 10 times the size of Earth would be a little smaller than Jupiter, and bigger than Saturn". Presumably, you there using "size" to imply "diameter/circumference"?
The word size, for planets, is most commonly used for diameter. Any other use should be qualified.
Arguments of perihelion/periapsis - can anyone explain?
Posted: Sun Mar 30, 2014 5:31 pm
by MargaritaMc
There is an interesting post by Emily Lakdawalla at The Planetary Society which includes an animated diagram showing the orbits of outer planets, Pluto, Sedna, and 2012 VP113
Emily quotes Trujillo and Sheppard as noting that
Both Sedna and 2012 VP113 have similar arguments of perihelion (311° and 293°, respectively). The orbital element ω describes the angle between the point of perihelion and where a body’s orbit crosses the celestial plane
As "arguments of perihelion" is a new term for me, I looked it up in Wikipedia (=argument of periapsis) but am still in the dark as, from that the Wikipedia articlecan not see what angles such as 311° and 293° would mean, partly because I'm not yet able to understand the mathematics given and partly because I don't see why a Reflex Angle would be used. In brief, I'm puzzled. Can anyone enlighten me?
Here is the Wikipedia diagram and definition for argument of periapsis
http://en.wikipedia.org/wiki/Argument_of_periapsis
An argument of periapsis of 0° means that the orbiting body will be at its closest approach to the central body at the same moment that it crosses the plane of reference from South to North. An argument of periapsis of 90° means that the orbiting body will reach periapsis at its northmost distance from the plane of reference.
If we rotate the axis of the orbit around the focus, then the rotation angle is the argument of perihelion (ω). This is demonstrated in the diagram below.
Margarita
Re: Solar System has a new most-distant member
Posted: Sun Mar 30, 2014 5:42 pm
by geckzilla
I take it to mean something similar to eccentricity but it's exact because if you know it then you probably know the orientation of the orbit while eccentricity will only get you the shape. That said, no, I really don't understand it, either.
Re: Arguments of perihelion/periapsis - can anyone explain?
Posted: Sun Mar 30, 2014 5:43 pm
by Chris Peterson
MargaritaMc wrote:There is an interesting post by Emily Lakdawalla at The Planetary Society which includes an animated diagram showing the orbits of outer planets, Pluto, Sedna, and 2012 VP113
Emily quotes Trujillo and Sheppard as noting that
Both Sedna and 2012 VP113 have similar arguments of perihelion (311° and 293°, respectively). The orbital element ω describes the angle between the point of perihelion and where a body’s orbit crosses the celestial plane
As "arguments of perihelion" is a new term for me, I looked it up in Wikipedia (=argument of periapsis) but am still in the dark as, from that the Wikipedia article can not see what angles such as 311° and 293° would mean, partly because I'm not yet able to understand the mathematics given and partly because I don't see why a Reflex Angle would be used. In brief, I'm puzzled. Can anyone enlighten me?
Here is the Wikipedia diagram and definition for periapsis
In this image, the perihelion point of the orbit is at the top right, where the purple line intersects it. As shown, the argument of perihelion is around 90°. Now consider that point to be the aphelion, instead. That would place the perihelion all the way down into the bottom left. The angle that measures the argument of perihelion would sweep from the ascending node, through the aphelion point, through the descending node, and around to the perihelion point, and have a value near 270° in this image (thus, a reflex angle).
Re: Arguments of perihelion/periapsis - can anyone explain?
Posted: Sun Mar 30, 2014 6:08 pm
by MargaritaMc
Chris Peterson wrote:
In this image, the perihelion point of the orbit is at the top right, where the purple line intersects it. As shown, the argument of perihelion is around 90°. Now consider that point to be the aphelion, instead. That would place the perihelion all the way down into the bottom left. The angle that measures the argument of perihelion would sweep from the ascending node, through the aphelion point, through the descending node, and around to the perihelion point, and have a value near 270° in this image (thus, a reflex angle).
Thanks very much. I think I'm beginning to glimpse it.
Is it possible for you to give an example drawn from, say Mars? Something whose orbit I am familiar with? Or Pluto, if it's better to have an example of an orbit that is eccentric and oblique (is that the right term for the slant of Pluto's orbital plane?)
M
Re: Arguments of perihelion/periapsis - can anyone explain?
Posted: Sun Mar 30, 2014 7:40 pm
by Chris Peterson
MargaritaMc wrote:Is it possible for you to give an example drawn from, say Mars? Something whose orbit I am familiar with? Or Pluto, if it's better to have an example of an orbit that is eccentric and oblique (is that the right term for the slant of Pluto's orbital plane?)
The above image shows the six conventional (Keplerian) orbital elements. The three that are easy to understand are the inclination, which is the angle the orbit is tipped out of a reference plane. When we're talking about Solar System bodies that orbit the Sun, that reference plane is almost always the ecliptic. Also easy to understand is the eccentricity, which describes just how close or far from circular the elliptical orbit is. And the last simple one is the semi-major axis, which describes the size of the ellipse (equivalent to radius for a circle). Also pretty easy to understand is the longitude of the ascending node, which is an angle from a reference direction (the northbound equinox) that describes where the body in an inclined orbit passes upwards across the ecliptic.
The two less obvious elements are the argument of perihelion (or periapsis), which describes how the elliptical orbit is rotated with respect to the ecliptic- specifically, the angle of the perihelion point with respect to the ascending node. Imagine an elliptical plate that you've tossed onto the table, and it does a sort of rotating dance before settling down. At any point in that dance, its argument of perihelion is changing. And finally, the mean anomaly is what tells you where in the orbit you actually find the body. That is, all five of the first terms just describe the shape of the orbital path. The mean anomaly is the only one that is a function of time- where on the path the body is at that time.
I don't know how an example with a planet would be more helpful. Most planets have such low inclinations and nearly circular orbits that it actually obscures the meaning of some orbital elements. Pluto is pretty different, so we can look at that. Maybe it will help. Here are its orbital elements:
Semimajor axis (AU) 39.48168677
Orbital eccentricity 0.24880766
Orbital inclination (deg) 17.14175
Longitude of ascending node (deg) 110.30347
Longitude of perihelion (deg) 224.06676
Mean longitude (deg) 238.92881
It's an elliptical orbit, with a maximum distance from the ellipse center of 39.48 AU. It's quite eccentric (0.25), which means that its closest distance to the ellipse center is much less (don't confuse these distances with the perihelion and aphelion, which are distances from the Sun, not the ellipse center. The Sun is at one focus of the ellipse, not the center.) Pluto's orbit is tilted 17° out of the ecliptic plane. The point where Pluto crosses that plane in an upwards direction is 110° from the vernal equinox (which is the angle where Earth's celestial equator intersects the ecliptic at the March equinox). The ellipse is rotated such that perihelion is 224° CCW from the ascending node. The mean longitude needs to be evaluated at a specific time to determine where in its orbit Pluto is at that time.
Thank you VERY much indeed, Chris! I really appreciate your help.
Margarita
Re: Solar System has a new most-distant member
Posted: Sun Mar 30, 2014 9:35 pm
by MargaritaMc
There is a useful summarising article about the finding of 2012 VP113 at New Scientist (not behind a pay wall)
New dwarf planet hints at giant world far beyond Pluto
... Intriguingly, Sheppard's team also found a strange alignment when they looked at the orbits of 2012 VP113, Sedna and 10 other objects that lie closer to the sun. "It was a big surprise to us," he says.
One explanation for the alignment could be the tug of a rocky planet that is 10 times the mass of Earth that orbits the sun at 250 AU, the team calculate. That world would be cold and faint – and would push and pull at the closer objects like a distant but powerful puppeteer.
NASA's Wide-field Infrared Survey Explorer (WISE) scoured this region of space in 2010 and 2011 searching for a so-called Planet X and came up empty.
However, WISE was looking for the tell-tale warmth of gas giants – a rocky "super-Earth", like the one Sheppard's team suggest, would be too cold for the telescope to pick up. "This is too faint for WISE," says Ned Wright, the space telescope's principal investigator.
<<On the heels of last week's reports of a second Sedna... A new, likely large member of the Kuiper belt. With an absolute magnitude of about 3.0, the new object currently known as 2013 FY27 is the ninth brightest object beyond Neptune. FY27 was discovered by Scott Sheppard and Chad Trujillo, in the same survey that yielded VP113, the second Sedna. FY27 is currently about 80 astronomical units from the Sun, similar to VP113's current distance, and therefore one of the most distant currently observable objects in the solar system.
Remember, what made VP113 unusual wasn't its current distance from the Sun; it was the shape of VP113's orbit and the fact that it never gets closer than about 80 AU from the Sun. A lot of people are getting confused about this, reporting VP113 as the most distant object in the solar system. It isn't; Eris is farther away, and so is Sedna.>>
