NASA DAWN: Mysterious Bright Spot on Dwarf Planet Ceres

A mysterious white spot can be seen in the newest images from NASA's Dawn spacecraft, which is rapidly approaching the dwarf planet. 

Credit: NASA /JPL-Caltech /UCLA /MPS /DLR /IDA /PSI

A strange, flickering white blotch found on the dwarf planet Ceres by NASA's Dawn spacecraft has scientists scratching their heads.

The white spot on Ceres in a series of new photos taken on Jan. 13 by NASA's Dawn spacecraft, which is rapidly approaching the round dwarf planet in the asteroid belt between the orbits of Mars and Jupiter, but when the initial photo release on Monday (Jan. 19), the Dawn scientists gave no indication of what the white dot might be.

"Yes, we can confirm that it is something on Ceres that reflects more sunlight, but what that is remains a mystery," Marc Rayman, mission director and chief engineer for the Dawn mission, told Space.com in an email.




The new images show areas of light and dark on the face of Ceres, which indicate surface features like craters, but at the moment, none of the specific features can be resolved, including the white spot.

"We do not know what the white spot is, but it's certainly intriguing," Rayman said. "In fact, it makes you want to send a spacecraft there to find out, and of course that is exactly what we are doing! So as Dawn brings Ceres into sharper focus, we will be able to see with exquisite detail what [the white spot] is."

Ceres is a unique object in our solar system. It is the largest object in the asteroid belt and is classified as an asteroid. It is simultaneously classified as a dwarf planet, and at 590 miles across (950 kilometers, or about the size of Texas), Ceres is the smallest known dwarf planet in the solar system.

The $466 million Dawn spacecraft is set to enter into orbit around Ceres on March 6. Dawn left Earth in 2007 and in the summer of 2011, it made a year-long pit stop at the asteroid Vesta, the second largest object in the asteroid belt.

NASA New Horizon Mission 2015, the year of the Dwarf Planet

This “movie” of Pluto and its largest moon, Charon, by NASA’s New Horizons spacecraft taken in July 2014 clearly shows that the barycenter, the centre of mass of the two bodies, resides outside (between) both bodies. 

The 12 images that make up the movie were taken by the spacecraft’s best telescopic camera, the Long Range Reconnaissance Imager (LORRI), at distances ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). 

Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto’s surface. 

Credit: NASA /Johns Hopkins University Applied Physics Laboratory /Southwest Research Institute

The New Horizons mission became the first mission of NASA's New Frontiers program, beginning development in 2001.

The probe was launched on January 19, 2006, atop an Atlas V 551 (5 solid rocket boosters plus a third stage).

Utilising more compact and lightweight electronics than its predecessors to the outer planets, Pioneer 10 & 11, and Voyager 1 & 2, the combination of reduced weight, a powerful launch vehicle, plus a gravity assist from Jupiter has lead to a nine year journey.

On December 6, 2014, New Horizons was taken out of hibernation for the last time and now remains powered on until the Pluto encounter.

The arrival date of New Horizon is July 14, 2015. A telescope called the Long Range Reconnaissance Imager (LORRI) has permitted the commencement of observations while still over 240 million kilometers (150 million miles) from Pluto.

The first stellar-like images were taken while still in the Asteroid belt in 2006.

NASA's New Horizons Spacecraft will Encounter Dwarf Planet Pluto in 2015

This artist's rendering shows NASA's New Horizons spacecraft during its flyby of Pluto and its moons on July 14, 2015. 

The spacecraft awoke from its final hibernation period on Dec. 6, 2014 in preparation for the epic Pluto encounter at the edge of the solar system.

Credit: Johns Hopkins University Applied Physics Laboratory /Southwest Research Institute (JHUAPL/SwRI)

Pluto, get ready for your close-up: A NASA spacecraft has roused itself from the final slumber of its nine-year trek to the edge of the solar system, setting the stage for the first close encounter with Pluto next year.

The New Horizons spacecraft, currently located 2.9 billion miles (4.6 billion kilometers) from Earth, had been in hibernation since August, with most of its systems turned off to reduce wear, but late Saturday (Dec. 6), mission scientists received a confirmation signal from New Horizons at the probe's Mission Operations Center here at the Johns Hopkins Applied Physics Laboratory.

The probe is now wide awake for its 2015 flyby of Pluto.

At the time of its wakeup call, New Horizons spacecraft was just over 162 million miles (261 million km) from Pluto.

About 20 people gathered in a conference room here at APL to await the signal from New Horizons.

NASA DAWN: Spacecraft operating normally after safe mode triggered

Artist concept of NASA's Dawn spacecraft orbiting Ceres during an upcoming flyby. 

Credit: NASA/JPL-Caltech/UCLA

The Dawn spacecraft has resumed normal ion thrusting after the thrusting unexpectedly stopped and the spacecraft entered safe mode on September 11.

That anomaly occurred shortly before a planned communication with NASA's Deep Space Network that morning.

The spacecraft was not performing any special activities at the time.

Engineers immediately began working to restore the spacecraft to its normal operational state.

The team determined the source of the problems, corrected them, and then resumed normal ion thrusting on Monday night, Sept. 15.

"This anomaly presented the team with an intricate and elaborate puzzle to solve," said Robert Mase, Dawn project manager at NASA's Jet Propulsion Laboratory in Pasadena, California.

After investigating what caused the spacecraft to enter safe mode, the Dawn team determined that it was likely triggered by the same phenomenon that affected Dawn three years ago on approach to the protoplanet Vesta: An electrical component in the ion propulsion system was disabled by a high-energy particle of radiation.

"We followed the same strategy that we implemented three years ago to recover from a similar radiation strike, to swap to one of the other ion engines and a different electronic controller so we could resume thrusting quickly," said Dawn Mission Director and Chief Engineer Marc Rayman of JPL.

"We have a plan in place to revive this disabled component later this year."

Complicating the issue, the team discovered that the spacecraft had experienced not just one anomaly, but also a second one that affected the ability to point the main antenna at Earth to communicate.

Because the spacecraft could not communicate using its main antenna, the team had to utilize the weaker signals of another antenna, slowing their progress.

In addition, Dawn is so far from Earth that radio signals take 53 minutes to make the round trip.

Although they have not yet specifically pinpointed the cause of this issue, it could also be explained by a high-energy particle corrupting the software running in the main computer.

Ultimately the team reset the computer, which restored the pointing performance to normal.

As a result of the change in the thrust plan, Dawn will enter into orbit around dwarf planet Ceres in April 2015, about a month later than previously planned.

Ceres

The plans for exploring Ceres once the spacecraft is in orbit, however, are not affected.

Vesta

Dawn orbited Vesta, the second most massive object in the main asteroid belt, from July 2011 until September 2012.

The spacecraft's ion propulsion system enabled it to spiral away from Vesta and head toward Ceres, the most massive object in that region.

SEDNA: Dwarf Planet on the outer regions of Solar System

Sedna is a dwarf planet on the far outer reaches of the solar system.

Credit: NASA

Sedna is a dwarf planet that is one of the most distant bodies found in our solar system.

The object's closest approach to the sun is far greater than Pluto's distance away from Earth, at a spot where the sun is so tiny, according to NASA, that you could blot it out with a pin.

At 8 billion miles (12.8 billion kilometers) away, it's hard to figure out things such as surface features, but one thing astronomers have been able to identify is Sedna's distinct reddish colour.

Mike Brown

In 2004, it was described as the second-reddest object in our solar system, after Mars.

Sedna was discovered by a team led by Mike Brown, an astronomer at the California Institute of Technology.

The discovery of Sedna and other objects similar to it was a large impetus behind demoting Pluto from planetary status in 2006.

Image of Sedna, taken by Hubble Space Telescope

Discovery and basic statistics
Brown's team found Sedna in 2003 as part of a larger survey of the solar system that began in 2001.

Using the Samuel Oschin Telescope at the Palomar Observatory (east of San Diego) as well as Palomar's Quasar Equatorial Survey Team (QUEST) camera, the astronomers would take pictures of a tiny spot in the sky, one per hour for three hours, and see if they could find something that moved, Brown said in an explanation page about the discovery.

"The many billions of stars and galaxies visible in the sky appear stationary, while satellites, planets, asteroids, and comets appear to move. Objects in the inner Oort Cloud are extremely distant and so move extremely slowly," he said.

The Oort Cloud expands from a narrow belt on its inner edge
 into a large sphere farther from the Sun.

The Oort Cloud is a theorized area far in the solar system that is supposed to contain billions of icy objects that, if they receive a gravitational push toward the sun and warm up, turn into comets as the sun's energy melts the ice.

Sedna, however, was much bigger than a comet. Estimates for Sedna's size vary, but it is believed to be slightly smaller than the size of Pluto (1,400 miles or 2,250 kilometers in diameter).

Sedna takes some time to orbit the sun, not only because of its vast distance but also because its orbit is so elliptical or oval-shaped.

The dwarf planet takes roughly 10,000 years to complete one circuit around the sun. At the time of its discovery, it was at one of the closest points of its orbit to the sun, making it easier to spot.

Credit: Nasa

More Information: An explanation page about the SEDNA discovery

Pluto: Three possible models of Dwarf Planet ahead of New Horizons visit

Interior structure models assumed for Pluto.

Two space researchers, Amy Barr, with Brown University and Geoffrey Collins with Wheaton College, have published a paper in the journal Icarus in which they describe three possible interior models of the former planet Pluto.

They suggest the possibilities include: 

1. an undifferentiated rock/ice mixture, 
2. a differentiated rock/ice mixture, and an ocean covered with ice. 
3. The third possibility suggests the likelihood, they claim, of tectonic action on the dwarf planet.

Pluto

A close up view of the planet by space probe New Horizons due to arrive next year, should help clarify which scenario is most likely.

Amy Barr

Scientists believe that Pluto came to exist as it does today, in part due to a collision billions of years ago that led also to the formation of its moon Charon.

Charon

When celestial bodies collide, not only do they knock each other around, they produce heat—heat, the researchers suggest that could still be evident today.

Barr and Collins are leading towards a theory that suggests that shortly after impact, Pluto and Charon were much closer together, the gravity attraction between them would have caused both to be egg shaped.

As time passed, melted ice from the impact would have created an icy crust on top of an ocean on Pluto, and then, as Charon moved farther away, the attractive pull would have diminished, causing ice plates to form and crack against one another, a form of tectonics.

Geoffrey Collins

If that were the case, the two add, then in all likelihood, when New Horizons begins sending back images, they should see evidence of such tectonic action—plate edges thrust into the air, for example.

There's just one catch, Pluto circles the sun in an elliptical orbit, thus sometimes it's much closer to the sun than other times.

When near, it has a defined atmosphere, when far away however, its atmosphere actually freezes to its surface, something that could hide ridges in the ice and thus evidence of both tectonic activity and an ocean beneath the crust of ice.

New Horizons

Artist concept of New Horizons spacecraft.

Johns Hopkins University Applied Physics Laboratory (JHUAPL) /Southwest Research Institute (SwRI)

Since New Horizons will arrive during a time when its atmosphere is frozen to the surface, it might be difficult to determine which of the three proposed models actually describes the relationship between its exterior and interior.

Barr and Collins are optimistic that even in such a scenario, ridges should be apparent, proving that beneath Pluto's icy surface, lies an ocean, one that future researchers might one day sample.

More information: Tectonic Activity on Pluto After the Charon-Forming Impact, Icarus, Available online 4 April 2014. dx.doi.org/10.1016/j.icarus.2014.03.042 . Available on Arxiv: xxx.lanl.gov/abs/1403.6377

NASA DAWN: Ice on Ceres is an 'Interesting Paradox'

Hubble Space Telescope imaged the asteroid Vesta and the dwarf planet Ceres in 2007, both targets of NASA's Dawn mission. 

Credit: NASA, ESA, J. Parker (SwRI), L. McFadden (U Maryland)

As NASA's Dawn mission draws closer to its encounter with the dwarf planet Ceres in early 2015, excitement continues to mount for scientists looking forward to what the satellite might observe.

Britney Schmidt

Britney Schmidt, of the George Institute of Technology, and Nicole Gugliucci of CosmoQuest, recently hosted a Google+ Hangout titled 'Ceres: Great Expectations' to discuss the upcoming visit to the nearest dwarf planet in the solar system.

Orbiting in the asteroid belt, a little more than three times as far from the Sun as Earth, Ceres is thought to contain an icy mantle that makes up approximately a third of its mass.

"Ceres is very different and very exciting in a lot of ways, totally different from any place that we've been," Schmidt said in the broadcast. "It may be the only primarily icy planet that's out there, at least within reach."

Scratching the surface
Seen through a telescope, Ceres may not appear very exciting.

Scientists can use the light reflected off of a body to find out information about its composition.

"Ceres, to the eye, would appear basically pretty black because it's reflecting most colours more or less the same, and reflecting very little light at all," said Andy Rivkin of the Johns Hopkins University Applied Physics Lab.

Andy Rivkin

Even the infrared spectrum, which tends to reveal more information about asteroids such as Vesta—Dawn's first stop—provided very little information about its composition.

By utilizing instruments such as the SpeX instrument on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea in Hawaii, scientists were able to catch hints about the dwarf planet's surface.

These observations revealed suggestions of brucite, hydroxyls, and two other features Rivkin says are thought to be due to carbonate minerals.

"[This] makes Ceres one of only a few places where we've found carbonates," Rivkin said. "I think other than Earth and Mars, it's Ceres."

He went on to explain that scientists think water interacting with the minerals formed the brucite and the carbonates.

The layers of Ceres. Scientists think that the dwarf planet contains a rocky inner core surrounded by a thick mantle of water-ice. 

A thin outer crust covers the surface, with carbonates and other signs that water lay on the planet's skin at some point. 

Credit: NASA, ESA, and A. Feild (STScI)

"For Ceres, we think it is much more consistent with a body that had a lot of water available to interact with."

But water, considered a potential habitat for life to start, can't exist on the surface of the dwarf planet in either solid or liquid form.

"We see no real evidence for ice at the surface of Ceres," Rivkin said, noting that the dwarf planet is too warm. "However, conditions beneath Ceres' surface should allow buried ice to remain there."

At the same time, observations from the Hubble Space Telescope, as well as theoretical data such as the planet's density, suggest that a large amount of ice exists.

"That creates this interesting paradox. We think there's a lot of ice there, (but) we don't see any at the surface," Rivkin said.

"How that's going to translate into what we find when we show up there is still very much an open question."

William Shatner names Pluto Moon: Vulcan

In a voting campaign to pick names for two of Pluto's smallest moons one clear winner is "Vulcan," proposed by U.S. actor William Shatner of "Star Trek" fame.

Online ballot casting allowing the public to vote for the name of two recently discovered moons of the dwarf planet -- for now known as just P4 and P5 -- ended Friday, with Vulcan in first place followed by Cerberus.

Although a late addition to the candidate names the public could vote on, Vulcan piled up a big lead after Shatner, who played Capt. James T. Kirk in the popular television series and movies, campaigned for the name on Twitter.

Vulcan was the home planet of Kirk's first officer, Spock, played by Leonard Nimoy.

Officials at SETI, which conducted the public poll, said they considered it an appropriate candidate since Vulcan is also the name of the god of fire in Roman mythology.

"Vulcan is the Roman god of lava and smoke, and the nephew of Pluto." SETI scientist Mark Showalter wrote in a blog when the name was added to the list on Feb. 12. "Thanks to William Shatner for the suggestion!"

Although Vulcan and Cerberus won the name poll, the final decision on names for the moons will rest with the International Astronomical Union.

Astronomers have found five moons around Pluto so far, with three of them named: Charon, Nix and Hydra.

P4 was discovered in 2011, and P5 in 2012; both are only about 20 miles in diameter.

Pluto: It's Atmosphere More Extensive Than Thought

Artist’s impression of how the surface of Pluto might look. The image shows patches of pure methane on the surface.

CREDIT: ESO/L. Calçada

A new simulation of Pluto's upper atmosphere shows that it extends so far from the planet that stray molecules may be deposited on its largest moon, Charon.

The new model predicts that Pluto's atmosphere can extend as far as 6,456 miles (10,390 kilometers) into space, or about 4.5 times the diameter of Pluto. That's more than halfway to Charon.

"That is amazing, from my perspective," said Justin Erwin, the lead author of the paper and a Ph.D. student at the University of Virginia.

Researchers combined two previously known models of Pluto's atmosphere to better estimate the escape rate of molecules into space. Their refinement made a big difference.

"Our [calculated escape rate] is a little bit smaller, but the small change in the escape rate causes a large change in the structure of the atmosphere," Erwin added.

Erwin's supervisor at the University of Virginia, Robert Johnson, was a co-author of the paper reporting the findings, which was published on the preprint site Arxiv and has been submitted to the journal Icarus for publication.

Fire and ice
Pluto's tenuous atmosphere is mainly composed of methane, nitrogen and poisonous carbon monoxide that likely comes from ice on the dwarf planet's surface. The size of the atmosphere changes as Pluto moves closer and farther from the sun in its elliptical orbit.

When Pluto swings near the sun, the sun's heat evaporates the ice and gases slowly escape into space. This process continues until Pluto moves away and the sun's heat fades. Then, the ice builds up until Pluto approaches the sun again.

Pluto's last close approach to the sun was in 1989. That is considered a fairly recent event, because it takes 248 years for the dwarf planet to orbit the sun once.

Researchers are trying to refine the escape rate of the gases ahead of the arrival of NASA's New Horizons probe at Pluto in 2015, so that the spacecraft knows what to look for.

For the new calculations, Erwin's team used previously published research from themselves and other scientists.

Destination Pluto: NASA's New Horizons Mission in Pictures

Dwarf planet Makemake: Confirmation that it lacks atmosphere

Dwarf planet Makemake is about two thirds of the size of Pluto, and travels around the Sun in a distant path that lies beyond that of Pluto but closer to the Sun than Eris, the most massive known dwarf planet in the Solar System.

Previous observations of chilly Makemake have shown it to be similar to its fellow dwarf planets, leading some astronomers to expect its atmosphere, if present, to be similar to that of Pluto.

However, the new study now shows that, like Eris, Makemake is not surrounded by a significant atmosphere.

The team, led by Jose Luis Ortiz (Instituto de Astrofisica de Andalucia, CSIC, Spain), combined multiple observations using three telescopes at ESO's La Silla and Paranal observing sites in Chile - the Very Large Telescope (VLT), New Technology Telescope (NTT), and TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) - with data from other small telescopes in South America, to look at Makemake as it passed in front of a distant star.

"As Makemake passed in front of the star and blocked it out, the star disappeared and reappeared very abruptly, rather than fading and brightening gradually. This means that the little dwarf planet has no significant atmosphere," says Jose Luis Ortiz.

"It was thought that Makemake had a good chance of having developed an atmosphere - that it has no sign of one at all shows just how much we have yet to learn about these mysterious bodies. Finding out about Makemake's properties for the first time is a big step forward in our study of the select club of icy dwarf planets."

Makemake's lack of moons and its great distance from us make it difficult to study, and what little we do know about the body is only approximate.

The team's new observations add much more detail to our view of Makemake - determining its size more accurately, putting constraints on a possible atmosphere and estimating the dwarf planet's density for the first time.

They have also allowed the astronomers to measure how much of the Sun's light Makemake's surface reflects - its albedo. Makemake's albedo, at about 0.77, is comparable to that of dirty snow, higher than that of Pluto, but lower than that of Eris.

It was only possible to observe Makemake in such detail because it passed in front of a star - an event known as a stellar occultation.

These rare opportunities are allowing astronomers for the first time to find out a great deal about the sometimes tenuous and delicate atmospheres around these distant, but important, members of the Solar System, and providing very accurate information about their other properties.

Occultations are particularly uncommon in the case of Makemake, because it moves in an area of the sky with relatively few stars.

Accurately predicting and detecting these rare events is extremely difficult and the successful observation by a coordinated observing team, scattered at many sites across South America, ranks as a major achievement.

"Pluto, Eris and Makemake are among the larger examples of the numerous icy bodies orbiting far away from our Sun," says Jose Luis Ortiz.

"Our new observations have greatly improved our knowledge of one of the biggest, Makemake - we will be able to use this information as we explore the intriguing objects in this region of space further."

NASA's Dawn spacecraft Leaves Vesta and sets sail for Ceres

After becoming the first spacecraft to enter orbit around an object in the main asteroid belt between Mars and Jupiter in July 2011, NASA’s Dawn spacecraft has spent the last year mapping the giant asteroid Vesta.

The spacecraft has now bid adieu to Vesta, one of the largest asteroids in the Universe and is on its way to the dwarf planet Ceres to continue its mission to help shed light on the evolution of our solar system.

Communications sent via NASA’s Deep Space Network confirmed Dawn’s departure from Vesta at about 11:26 p.m. US PDT on Tuesday, September 4.

Launched on September 27, 2007, it took the spacecraft almost four years to reach its first port of call, but the second leg of its journey is set to be a bit quicker with Dawn expected to arrive at Ceres early in 2015.

Dawn’s departure from Vesta was far from dramatic.

It gently spiraled out of the giant asteroid's orbit propelled by, what Marc Rayman, Dawn's chief engineer and mission director, called “a blue-green pillar of xenon ions,” emitted from the ion propulsion system that generates thrust by using electricity to ionize xenon.

NASA Dawn Asteroid Probe Hits Snag on Way to Dwarf Planet, Ceres

An artist's impression of the Dawn spacecraft in orbit around Vesta.

CREDIT: NASA/JPL-Caltech

A NASA spacecraft orbiting the huge asteroid Vesta has suffered a glitch last week, but mission controllers say it will not affect plans for its upcoming trip to Ceres, the largest asteroid or Dwarf Planet, in the solar system.

The malfunction on NASA's Dawn spacecraft occurred during a maneuver on Aug. 8, when one of the probe's reaction wheels that is used to maintain its position in space unexpectedly shut down.

Mission controllers discovered the problem during a routine communications dispatch the following day, on Aug. 9, said Marc Rayman, chief engineer and mission director of the Dawn mission.

"The wheel was operating normally, and then the internal friction increased enough that the software that we call 'fault protection' — it's a system software that looks at parameters on the spacecraft and monitors the performance of the different components — detected something unusual," Rayman reported.

"If something isn't within the limits we've specified, it takes action. In this case, when the friction got up to a certain level, it turned that wheel off."

Three impact craters of different sizes, arranged in the shape of a snowman, make up one of the most striking features on Vesta, as seen in this view from NASA’s Dawn mission. 

In this view the three “snowballs” are upside down, so that the shadows make the features easily recognizable. 

North is to the lower right in the image, which has a resolution of 230 feet (70 meters) per pixel. 

Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

At the time when one of the probe's reaction wheels failed, Dawn was preparing for its departure from Vesta, after spending more than a year studying the asteroid.

The spacecraft completed its science objectives at Vesta on July 24. Since then, Dawn has been using its ion thrusters to gradually spiral away from the space rock.

"The ion propulsion system, while very efficient, is also very gentle," Rayman explained.

"It only gradually climbs away from Vesta, spiraling in ever larger loops until the spacecraft is going fast enough and is far away enough from Vesta that Vesta can no longer hold it in its gravitational grip."