Unit 46

Ice Worlds, Pluto and Beyond

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Beyond Neptune

According to the International Astronomical Union this is this ends the Major planets.

SO what is beyond Neptune?

Beyond Neptune

Something called: Trans –Neptunian Objects

These objects (known as TNO) are nearly the same size as Pluto and are beyond Neptune's orbit

Pluto

Pluto

It was predicted by Percival Lowell, based on perturbation theory, but later discovered by Clyde Tombaugh (1906- 1/17/1997) (the first planet found by an American) in 1930 by a fortunate accident.

Pluto

– From its discovery in 1930 until 2006, Pluto was classified as a planet.

– In the late 1970s, following the discovery of minor planet 2060 Chiron in the outer Solar System and the recognition of Pluto's relatively low mass, its status as a major planet began to be questioned.

Pluto

• In the late 20th and early 21st centuries, while searching for more TNO, Mike Brown discovered in the outer Solar System, an object which he finally called: Eris in 2005, which is 27% more massive than Pluto.

• Never again will Pluto be the ninth planet, or the littlest planet, or the most distant planet.

• Dr. Mike Brown, California Institute of Technology (Caltech), Pasadena, Calif., associate professor of planetary astronomy and leader of the research team

On the International Astronomical Union (IAU) on August 24, 2006, limiting the number to eight and defines "planet“

PLANET:– a celestial body that, within the Solar System,

• is in orbit (path of one object around a point or another point) around the Sun;

• has sufficient mass for its self-gravity to overcome rigid body forces (is an idealization of a solid body of finite size in which deformation is neglected. In other words, the distance between any two given points of a rigid body remains constant in time regardless of external forces exerted on it.) so that it assumes a hydrostatic equilibrium (nearly round) shape; and

• has cleared the neighbourhood (of its own orbital zone, meaning it has become gravitationally dominant, and there are no other bodies of comparable size other than its own satellites or those otherwise under its gravitational influence) around its orbit;

– or

PLANET:– or within another system,

• is in orbit around a star or stellar remnants; • has a mass below the limiting mass for thermonuclear fusion of

deuterium; and • is above the minimum mass/size requirement for planetary

status in the Solar System.

–

Pluto

• Pluto, considered a planet for 76 years, was reclassified as a dwarf planet in 2006.

• On August 24, 2006, The International Astronomical Union (IAU), the officially defines a "dwarf planet”

Dwarf planet:

• a celestial body that, within the Solar System,• is in orbit around the Sun; • has sufficient mass for its self-gravity to

overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape;

• has not cleared the neighbourhood around its orbit; and

• is not a satellite

• The term "dwarf planet" applies only to objects in the Solar System. and is quite distinct from "planet" and "small solar system body".

Pluto

– After the reclassification, Pluto was added to the list of minor planets and given the number 134340.

– A number of scientists hold that Pluto should continue to be classified as a planet, and that other dwarf planets should be added to the roster of planets along with Pluto

Trans-Neptunian Objects

DWARF PLANETS

• Plutinos are bodies that orbit the Sun at more or less the same distance as Pluto

Trans-Neptunian Objects

• Plutinos are small icy bodies orbiting the Sun beyond called Trans-Neptunian Objects, or TNOs

– More than 100 have been found to date!

Pluto

Pluto

– Rotation: 6 days/ 9 hrs/ 18 min (RETROGRADE)

– Revolves: 248 years– distance: 39.529 AU

3 674 490 973 miles– Gravity: .06– Tilt 50°– Incline: 17.2– MASS: 1.27e22 kg

Pluto

Pluto

– SIZE: 1413 miles– Comp:

• More resembles the moon Triton

• Pluto's bulk density is 2,100 kg/m3, similar to Callisto‘s

• Pluto is a mix of water ice, rock, methane and frozen nitrogen.

Pluto

Pluto is a mix of water ice, rock, methane and frozen nitrogen.

PlutoPluto orbit is very eccentric

Pluto

From an aerial view, it appears that Pluto crosses the orbit of Neptune.

Neptune’s orbit

Pluto

But as you can see from a side view, Pluto DOES NOT cross the orbit of Neptune.

Pluto’s Atmosphere• When Pluto is within Neptune’s orbit,

it has an atmosphere!– As the planet moves further out in

to the solar system, the atmosphere snows out onto the surface.

Pluto’s Atmosphere• Little is known about Pluto's

atmosphere, but it probably consists primarily of nitrogen with some carbon monoxide and methane.

• It is extremely tenuous, the surface pressure being only a few microbars.

Pluto’s Atmosphere• Pluto's atmosphere may exist as a gas

only when Pluto is near its perihelion; for the majority of Pluto's long year, the atmospheric gases are frozen into ice.

Pluto’s Atmosphere• Near perihelion, it is likely that some of

the atmosphere escapes to space perhaps even interacting with its moons.

Pluto’s MoonsFormation of Pluto's moons. • 1: a TNO object nears Pluto;

Pluto’s MoonsFormation of Pluto's moons. • 2: the KBO impacts Pluto;

Pluto’s MoonsFormation of Pluto's moons. • 3: a dust ring forms around Pluto;

Pluto’s MoonsFormation of Pluto's moons. • 4: the debris aggregates to form Charon;

Pluto’s MoonsFormation of Pluto's moons. • 5: Pluto and Charon relax into spherical bodies.

Pluto’s MoonsCharon

– The innermost moon,– Was discovered by James Christy on June 22, 1978,

nearly half a century after Pluto. – Size: 749 miles– Rotation, Rev, Distance, all the same as Pluto

Pluto’s MoonsCharon

– Rotation: 6 days/ 9 hrs/ 18 min (RETROGRADE)

– Revolves: 248 years– distance: 39.529 AU

3 674 490 973 miles– Tilt 50°– Incline: 17.2– Almost like a double

planet system

Pluto’s MoonsCharon• Pluto and its largest moon Charon would

fit comfortably within the United States.

Pluto’s MoonsCharon• Charon orbits Pluto at a steep angle to

the ecliptic, and Pluto’s axis is heavily tipped as well

Pluto’s MoonsOTHER moons of PLUTO

– Two outer moons were imaged by the Hubble Space Telescope Pluto Companion Search Team in May 2005.

With the orbits confirmed, the moons have been given definitive names: Hydra (Pluto III, formerly S/2005 P 1) and Nix (Pluto II, formerly S/2005 P 2).

Pluto’s MoonsOTHER

– Further Hubble observations were made in February and March 2006.

– The possibility of rings where created by impacts on the smaller moons scientist think.

Pluto’s MoonsOTHER moons of PLUTO

– The fourth moon was announced in July 2011.

– Currently called P4

Pluto’s MoonsOTHER moons of PLUTO

– A fifth moon was discovered in July 2012.

Pluto

• Pluto is the only planet in the solar system that we have not visited.

• However that is soon to change.

Pluto • 2015 New Horizon spacecraft will do a Pluto Flyby 

Pluto • New Horizon

• ~45000mph (12mi/sec)• NY to LA in 3½ min• Pass Jupiter 13 months• 13 years trip gets there about July2015

•  

Pluto • NASA probe, New Horizon, is planning to arrive at Pluto while the atmosphere is still unfrozen.

• The probe will record the freezing of the atmosphere.  

Beyond NeptuneMost TNOs, like Pluto, come from an area that is just beyond Neptune called the

Beyond Neptune

Trans-Neptunian ObjectsOTHERS

MakemakeHaumea

Let us LOOK at TNO’s

Trans-Neptunian Objects

• More than 130 have been discovered, one of them larger than Pluto!

• Other new member of "dwarf planet" are Eris and Ceres.

Trans-Neptunian Objects• Here is a picture of

Ceres, Pluto, and Eris

Trans-Neptunian ObjectsNot the typical asteroid… This one is ROUND .

Trans-Neptunian Objects

Ceres • Ceres was discovered on

Jan 01, 1801 by Guiseppe Piazzi.

• Ceres has not yet been seen up close but NASA's Dawn spacecraft will visit it in 2015

Trans-Neptunian Objects

Ceres • The largest of the asteroids• ITS ROUND• The smallest of the dwarf

planets.• Orbit: 277 131 552 mile

from the Sun (average) • Diameter: 590 miles

Trans-Neptunian ObjectsERIS (2003 UB313)• Eris was first

found by Mike Brown and his team in 2003.

• It was not until 2005 that Eris was identified as another possible planet in our solar system.

Trans-Neptunian Objects

ERIS (2003 UB313)• Is the largest

known dwarf planet in our solar system.

• It is a little larger than Pluto. Eris is about 1491 miles (2400 Km) wide.

Trans-Neptunian Objects

ERIS (2003 UB313)• Observations have

led scientists to believe it has frozen methane on its surface.

• Eris appears gray in color.

Trans-Neptunian ObjectsERIS (2003 UB313)• Eris was the most

distant member of our solar system.

• It is 3 times farther out than Pluto. One trip around the Sun takes 557 Earth years for Eris.

Trans-Neptunian ObjectsERIS (2003 UB313)• Eris is the most

distant member of our solar system known at this time.

• It is 3 times farther out than Pluto. One trip around the Sun takes 557 Earth years for Eris.

Trans-Neptunian ObjectsERIS • Dysnomia

is the only moon of Eris that we now know about

Trans-Neptunian ObjectsSEDNAVery far far away--farther than Pluto is another Dwarf Planet.8 billion miles away.

Sedna will be at its closest approach, about 72 years from now and then it will beginning its 10,500-year trip back to the far reaches of the solar system.

Trans-Neptunian ObjectsSEDNAThe last time Sedna (the red dot) was this close to the sun, Earth was just coming out of the last ice age.

The next time it comes back, the world might again be a completely different place.

Trans-Neptunian ObjectsSEDNAInclude its size and reddish color.

After Mars, it is the second reddest object in the solar system.

It is estimated Sedna is approximately 3/4 the size of Pluto

Trans-Neptunian ObjectsSEDNAColdest known region of our solar system, where temperatures never rise above -240° Celsius (-400°F)

Trans-Neptunian ObjectsOTHERSHaumea with its moons, Hiʻiaka and Namaka

Haumea - A New Birth in Consciousness(pronounced how-MAY-ah)discovered on Dec 28, 2004 by Mike Brown

Trans-Neptunian ObjectsOTHERS (136472) Makemake (previously known as 2005 FY9

In Search of the Golden Egg(pronounced MAH-keh MAH-keh - "e" is pronounced "ay" in Polynesian)

Discovered on March 31, 2005 by Mike Brown

Trans-Neptunian ObjectsOTHERS• Quaoar (pronounced kwah-whar) • name given to the "creation force“• Discovered by Mike Brown and Chad Trujillo in a digital

image taken on June 4, 2002

Trans-Neptunian Objects

OTHERS• Quaoar is about 746 miles in diameter--about one-

tenth the diameter of Earth, about half the size of Pluto, and larger than the four primary asteroids combined.

Trans-Neptunian ObjectsOTHERS• Quaoar has an

orbital period of 288 years

• Orbiting the sun in a near perfect circle

Trans-Neptunian ObjectsOTHERS• Orcus - Oath of the Soul

• Discovered on Feb 19, 2004 by Mike Brown

• Bit smaller than Pluto, Orcus has a nearly identical orbital size, orbital period (year), and orbital inclination, and it has a moon like Pluto.

Trans-Neptunian ObjectsOTHERS• However, Orcus' orbital plane's orientation in our

solar system is tilted in the opposite direction from Pluto's. Orcus is clearly Pluto's compliment.

Trans-Neptunian ObjectsOTHERS• Orcus's 247 year orbit is shaped similarly to Pluto's

(both have perihelia above the ecliptic), but is differently oriented.

• Orcus is sometimes described as the "anti-Pluto".

Oort CloudSO what is next?

Comets also are cosmic debris, probably planetesimals that originally resided in the vicinity of the orbits of Uranus and Neptune rather than in the warmer regions of the asteroid belt.

Thus, the nuclei of comets are icy balls of frozen water, methane, and ammonia, mixed with small pieces of rock and dust, rather than the largely volatile-free stones and irons that typify asteroids.

Oort CloudSO…

In the most popular theory, icy planetesimals in the primitive solar nebula that wandered close to Uranus or Neptune but not close enough to be captured by them were flung to great distances from the Sun, some to be lost from the solar system while others populated what was to become a great cloud of cometary bodies, perhaps 10 trillion in number.

Such a cloud was first hypothesized by the Dutch astronomer Jan Hendrik Oort.

Oort CloudOort Cloud• In 1950. Dr. Jan Oort noticed that:– No comet has been observed with an orbit that indicates that it came from interstellar space

– There is a strong tendency for aphelia of long period comet orbits to lie at a distance of about 50,000 AU

– There is no preferential direction from which comets come

THE END