Spotlight On Pluto’s Frozen Polar Canyons

This enhanced color view Long canyons run vertically across the polar area—part of the informally named Lowell Regio, named for Percival Lowell, who founded Lowell Observatory and initiated the search that led to Pluto’s discovery. The widest of the canyons is about 45 miles (75 kilometers) wide and runs close to the north pole. Roughly parallel subsidiary canyons to the east and west are approximately 6 miles (10 kilometers) wide.
This enhanced color view shows long canyons running vertically across Pluto’s north polar region — part of the informally named Lowell Regio, named for Percival Lowell, who founded Lowell Observatory and initiated the search that led to Pluto’s discovery. The widest of the canyons is about 45 miles (75 km) wide and runs close to the north pole. Roughly parallel secondary canyons to the east and west are approximately 6 miles (10 km) wide. Click for a hi-res view. Credit: NASA/JHUAPL/SRI

Pluto’s frozen nitrogen custard “heart” has certainly received its share of attention. Dozens of wide and close-up photos homing on this fascinating region rimmed by mountains and badlands have been relayed back to Earth by NASA’s New Horizons probe after last July’s flyby. For being only 1,473 miles (2,370 km) in diameter, Pluto displays an incredible diversity of landscapes.

Annotated version of Pluto's north polar region.
Annotated version showing sinuous valleys, canyons and depressions and irregular-shaped pits. Credit: NASA/JHUAPL/SRI with additional annotations by the author

This week, the New Horizons team shifted its focus northward, re-releasing an enhanced color image of the north polar area that was originally part of a high-resolution full-disk photograph of Pluto. Inside of the widest canyon, you can trace the sinuous outline of a narrower valley similar in outward appearance to the Moon’s Alpine Valleycut by a narrow, curvy rill that once served as a conduit for lava.

A composite of enhanced color images of Pluto (lower right) and Charon (upper left), taken by NASA's New Horizons spacecraft as it passed through the Pluto system on July 14, 2015. This image highlights the striking differences between Pluto and Charon. The color and brightness of both Pluto and Charon have been processed identically to allow direct comparison of their surface properties, and to highlight the similarity between Charon's polar red terrain and Pluto's equatorial red terrain. Pluto and Charon are shown with approximately correct relative sizes, but their true separation is not to scale.
A composite of enhanced color images of Pluto (lower right) and Charon, taken by NASA’s New Horizons spacecraft on July 14, 2015. This image highlights the striking differences between Pluto and Charon. The color and brightness of both Pluto and Charon have been processed identically to allow direct comparison of their surface properties, and to highlight the similarity between Charon’s polar red terrain and Pluto’s equatorial red terrain. Pluto and Charon are shown with approximately correct relative sizes, but their separation is not to scale. Credit: NASA/JHUAPL/SRI

We see multiple canyons in Pluto’s polar region, their walls broken and degraded compared to canyons seen elsewhere on the planet. Signs that they may be older and made of weaker materials and likely formed in ancient times when Pluto was more tectonically active. Perhaps they’re related to that long-ago dance between Pluto and its largest moon Charon as the two transitioned into their current tidally-locked embrace.

Cropped version showing three, odd-shaped pits that may reflect sinking of Pluto's crust. Credit:
Cropped version with arrows pointing to three, odd-shaped pits that may reflect sinking of Pluto’s crust. Credit: NASA/JHUAPL/SRI

In the lower right corner of the image, check out those funky-shaped pits that resemble the melting outlines of boot prints in the snow. They reach 45 miles (70 km) across and 2.5 miles (4 km) deep and may indicate locations where subsurface ice has melted or sublimated (vaporized) from below, causing the ground to collapse.

Notice the variation in color across the landscape from yellow-orange to pale blue. High elevations show up in a distinctive yellow, not seen elsewhere on Pluto, with lower elevations and latitudes a bluish gray. New Horizons’ infrared measurements show abundant methane ice across the Lowell Region, with relatively little nitrogen ice. The yellow terrains may be older methane deposits that have been more processed by solar UV light than the bluer terrain. The color variations are especially striking in the area of the collapse pits.

The new map shows exposed water ice to be considerably more widespread across Pluto's surface than was previously known - an important discovery.
The new map shows exposed water ice at Pluto to be considerably more widespread across its surface than was previously known. Its greatest concentration lies in the red-hued regions (in visual light) to the west of Tombaugh Regio, the large, heart-shaped feature. Credit: NASA/JHUAPL/SRI

Pluto’s icy riches include not only methane and nitrogen but also water, which forms the planet’s bedrock. NASA poetically refers to the water ice as “the canvas on which (Pluto’s) more volatile ices paint their seasonally changing patterns”. Recent images made in infrared light shows little or no water ice in the informally named places called Sputnik Planum (the left or western region of Pluto’s “heart”) and Lowell Regio. This indicates that at least in these regions, Pluto’s bedrock remains well hidden beneath a thick blanket of other ices such as methane, nitrogen and carbon monoxide.

To delve more deeply into Pluto, visit the NASA’s photojournal archive, where you’ll find 130 photos (and counting!) of the dwarf planet and its satellites.

Your Favorite Planet May Soon Turn Up In The Mail

The Postal Service will showcase some of the more compelling historic, full-disk images of the planets obtained during the last half-century of space exploration. Some show the planets’ “true color” like Earth and Mars — what one might see if traveling through space. Others, such as Venus, use colors to represent and visualize certain features of a planet based in imaging data. Still others (red storms on Uranus) use the near-infrared spectrum to show things that cannot be seen by the human eye. Credits: USPS/Antonio Alcalá © 2016 USPS
The Postal Service will showcase some of the more compelling historic, full-disk images of the planets obtained during the last half-century of space exploration. Some show the planets’ “true color” like Earth and Mars — what one might see if traveling through space. Others, such as Venus, use colors to represent and visualize certain features of a planet based in imaging data. Still others (red storms on Uranus) use the near-infrared spectrum to show things invisible to the human eye.
Credits: USPS/Antonio Alcalá © 2016 USPS

Whenever I go to the post office to pick up stamps I always ask for the most colorful ones. No dead president heads for me. Mailing letters is a rare thing nowadays — might as well choose something colorful and interesting. How sweet then that we’ll soon be able to pick and stick our favorite planets (and dwarf planet!) on the mail and send them flying off to far places.

The U.S. Postal Service sneak-previewed a new series of stamps earlier this year highlighting NASA’s Planetary Science program, including a do-over of a famous Pluto stamp commemorating the New Horizons’ historic 2015 flyby. Also in the works are eight new colorful Forever stamps featuring NASA images of the planets, a Global Forever stamp dedicated to Earth’s moon and a tribute to 50 years of Star Trek.

Pluto Explored! In 2006, NASA placed a 29-cent 1991 ‘Pluto: Not Yet Explored’ stamp in the New Horizons spacecraft. With the new stamp, the Postal Service recognizes the first reconnaissance of Pluto in 2015 by NASA’s New Horizon mission. The two separate stamps show an artists’ rendering of the New Horizons spacecraft and the spacecraft’s enhanced color image of Pluto taken near closest approach. Credits: USPS/Antonio Alcalá © 2016 USPS
New Horizons Principal Investigator Alan Stern (left), Johns Hopkins University Applied Physics Laboratory (APL) Director Ralph Semmel (center) and New Horizons Co-Investigator Will Grundy Lowell Observatory hold a print of an U.S. stamp with their suggested update since the New Horizons spacecraft has explored Pluto last July. Credit: NASA/Bill Ingalls

The New Horizons team, which placed a 29-cent 1991 “Pluto: Not Yet Explored” stamp on board the New Horizons spacecraft, is thrilled at the updated stamp recognizing the mission.

“The New Horizons project is proud to have such an important honor from the U.S. Postal Service,” said Alan Stern, New Horizons principal investigator from the Southwest Research Institute. “Since the early 1990s the old, ‘Pluto Not Explored’ stamp served as a rallying cry for many who wanted to mount this historic mission of space exploration. Now that NASA’s New Horizons has accomplished that goal, it’s a wonderful feeling to see these new stamps join others commemorating first explorations of the planets.”

Pluto Explored! In 2006, NASA placed a 29-cent 1991 ‘Pluto: Not Yet Explored’ stamp in the New Horizons spacecraft. With the new stamp, the Postal Service recognizes the first reconnaissance of Pluto in 2015 by NASA’s New Horizon mission. The two separate stamps show an artists’ rendering of the New Horizons spacecraft and the spacecraft’s enhanced color image of Pluto taken near closest approach. Credits: USPS/Antonio Alcalá © 2016 USPS
Pluto Explored! In 2006, NASA placed a 29-cent 1991 ‘Pluto: Not Yet Explored’ stamp in the New Horizons spacecraft. With the new stamp, the Postal Service recognizes the first reconnaissance of Pluto in 2015 by NASA’s New Horizon mission. The two separate stamps show an artists’ rendering of the New Horizons spacecraft and the spacecraft’s enhanced color image of Pluto taken near closest approach.
Credits: USPS/Antonio Alcalá © 2016 USPS

In the upcoming planet series, we’re treated to a color-enhanced Mercury taken by MESSENGER highlighting the planet’s varied terrains. Venus appears in all its naked volcanic glory courtesy of the Magellan probe which mapped the planet using cloud-penetrating radar. Like Mercury, it’s also color-enhanced since it’s impossible to see the surface in visual light even from orbit. Earth and Mars were photographed in natural light with orbiting satellites in tow.

Ten of the round Global Forever stamps of the full moon. Issued at the price of $1.20, this Global Forever stamp can be used to mail a one-ounce letter to any country to which First-Class Mail International service is available. Credits: USPS/Greg Breeding under the art direction of William Gicker © 2016 USPS
Ten of the round Global Forever stamps of the Full Moon. Issued at the price of $1.20, this Global Forever stamp can be used to mail a one-ounce letter to any country to which First-Class Mail International service is available.
Credits: USPS/Greg Breeding under the art direction of William Gicker © 2016 USPS

The Hubble Space Telescope photographed Jupiter in infrared light in 2004, capturing a rare triple transit of the moons Ganymede, Io and Callisto. Saturn comes to us from the Cassini probe, still in good health and routinely sending gorgeous images every month of the ringed planet and its moons. Pity the rings had to be trimmed, but it had to be done to keep all the globes close to the same relative size. Hubble took Uranus’ picture in infrared light, while the Neptune close-up was sent by the Voyager 2 spacecraft in 1989.

Celebrating the 50th anniversary of the television premiere, the new Star Trek Forever stamps showcase four digital illustrations inspired by the television program: the Starship Enterprise inside the outline of a Starfleet insignia, the silhouette of a crewman in a transporter, the silhouette of the Enterprise from above and the Enterprise inside the outline of the Vulcan salute. Credits: USPS/Heads of State under the art direction of Antonio Alcalá © 2016 USPS
Celebrating the 50th anniversary of the television premiere, the new Star Trek Forever stamps showcase four digital illustrations inspired by the television program. Credits: USPS/Heads of State under the art direction of Antonio Alcalá © 2016 USPS

2016 also marks the 50th anniversary of the television premier of Star Trek, which the post office will commemorate with the new Star Trek Forever stamps. They feature four digital illustrations inspired by the television program: the Starship Enterprise inside the outline of a Starfleet insignia, the silhouette of a crewman in a transporter, the silhouette of the Enterprise from above and the Enterprise inside the outline of the Vulcan salute.

The Global Moon stamp was issued on Feb. 22. You can pre-order the Pluto and planet stamps from USPS.com 30 days before their dedication between May 28 and June 4 at the World Stamp Show in New York. Expect the Star Trek series sometime this summer.

Astronomers Find Theoretical Evidence for Distant Gas Giant Planet in Our Solar System

Artistic rendering shows the distant view from theoretical Planet Nine back towards the sun. The planet is thought to be gaseous, similar to Uranus and Neptune. Hypothetical lightning lights up the night side.  Credit: Caltech/R. Hurt (IPAC)
Artistic rendering shows the distant view from theoretical Planet Nine back towards the sun. The planet is thought to be gaseous, similar to Uranus and Neptune. Hypothetical lightning lights up the night side. Credit: Caltech/R. Hurt (IPAC)

The astronomer known worldwide for vigorously promoting the demotion of Pluto from its decades long perch as the 9th Planet, has now found theoretical evidence for a new and very distant gas giant planet lurking way beyond Pluto out to the far reaches of our solar system.

In an obvious reference to the planethood controversy, the proposed new planet is nicknamed ‘Planet Nine’ and its absolutely huge! Continue reading “Astronomers Find Theoretical Evidence for Distant Gas Giant Planet in Our Solar System”

Dawn Unveils New Bright Features on Ceres in Striking Close-Ups

This image from NASA's Dawn spacecraft shows Kupalo Crater, one of the youngest craters on Ceres. The crater has bright material exposed on its rim and walls, which could be salts. Its flat floor likely formed from impact melt and debris.  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This image from NASA’s Dawn spacecraft shows Kupalo Crater, one of the youngest craters on Ceres. The crater has bright material exposed on its rim and walls, which could be salts. Its flat floor likely formed from impact melt and debris. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

NASA’s Dawn spacecraft has unveiled a new patch of intriguing bright features in the most recent series of striking close-up images taken just after the probe reached the lowest altitude it will ever reach during the mission.

From Dawn’s current altitude of 240 miles (385 kilometers) above Ceres, every image taken from now on of the “unique landforms” will be of the highest resolution attainable since the ship will never swoop down closer to the pockmarked surface for science. Continue reading “Dawn Unveils New Bright Features on Ceres in Striking Close-Ups”

Our Highest Resolution Views Yet of Pluto’s Surface

The Mountainous Shoreline of Sputnik Planum on Pluto. Great blocks of Pluto’s water-ice crust appear jammed together in the informally named al-Idrisi mountains. Some mountain sides appear coated in dark material, while other sides are bright. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

The New Horizons spacecraft has been slowly sending back all the images and data it gathered during its July flyby of the Pluto system. The latest batch of images to arrive here on Earth contains some of the highest resolution views yet that it captured of Pluto’s surface, taken during the spacecraft’s closest approach.

The images show a wide variety of spectacular craters, mountains and glaciers. The New Horizons team said the images have resolutions of about 250-280 feet (77-85 meters) per pixel – revealing features less than half the size of a city block on the diverse surface of the distant dwarf planet. The images are six times better than the resolution of the global Pluto map New Horizons obtained.
Continue reading “Our Highest Resolution Views Yet of Pluto’s Surface”

New Dwarf Planet is Most Distant Object Yet Observed in our Solar System

It has been estimated that there may be hundreds of dwarf planets in the Kuiper belt and Oort Cloud of the outer Solar System. So far we’ve found – and actually seen – just a few. This past week, one more dwarf planet was added to the list and comes in at the most distant object ever seen in the Solar System.

This newly found world, initially named V774104, is about 15.4 billion kilometers from the Sun. At 103 AU, it is three times further from the Sun than Pluto, and is more distant than the previous record holder, Eris, which lies at 97 AU.

The discovery of V774104 was announced by one of the astronomers who found the object, Scott Sheppard, from the Carnegie Institution for Science, at the American Astronomical Society’s Division for Planetary Sciences fall meeting last week. Sheppard, along with Chad Trujillo and David Tholen used Japan’s 8-meter Subaru Telescope in Hawaii to make the find.

Astronomers say this newly spotted dwarf planet shows the depths of our Solar System.

“The discovery of V774104 is more proof that the Solar System is bigger than we thought,” said astronomer Joseph Burns from Cornell University, who was not associated with the discovery. “We need a little more time to pin down the orbit and determine the object’s exact size, but it must be big to see it at this distance.”

The size of V774104 is currently estimated to be between 500 and 1000 kilometers in diameter, which is less than half Pluto’s size.

While the size of the object is of some interest to astronomers who are searching for KBOs, even more interesting is pinning down its orbit. With its recent discovery, the orbit of V774104 has yet to be tracked for long periods of time.

If the orbit of V774104 comes closer to the Sun, such as between 30 to 50 AU, then it would be considered an icy Kuiper Belt objects which are more common among bodies like this found so far. Their orbits are more elongated because they fall under the gravitational influence of Neptune.

Of even more interest are what Sheppard called “inner Oort Cloud objects,” (also called “sednoids”). Theses bodies exist in a part of the Solar System that astronomers used to think was fairy empty. Of the two previously observed objects in this class — Sedna and 2012 VP113. — their orbits never come closer to the Sun than 50 AU, and they have a semi-major axis greater than 150 AU. The eccentric orbits of these objects have yet to be explained.

Colin Johnston from the Armagh Planetarium clarifies:

This means at their closest to the Sun they are still beyond the Kuiper Belt which lies 30-50 au from the Sun. Only two other objects in this category are known: 90377 Sedna and 2012 VP113.

They intrigue astronomers as they inhabit what was expected to be a largely empty region between the Kuiper Belt and the Oort Cloud, the Solar System’s yet to observed reservoir of comets. As well, the current highly elliptical orbits of Sednoids cannot be their original orbits, the chance of smaller bodies in such eccentric paths accreting into objects hundreds of kilometres across is fantastically low. Sednoids must have originally formed in relatively circular orbits, possibly in the Oort Cloud.

“Non-eccentric orbits seem to be the anomaly here,” Burns told Universe Today.

So, this likely means that something other than the Sun is responsible for influencing the erratic orbits of such small objects like V774104. One theory is that there might be a large planet at the outer reaches of the Solar System influencing the orbits of these distant objects.

Of course, among some crowds that brings up the hypothetical Planet X. But Burns was quick to dismiss that idea.

“While we certainly don’t understand well these objects, we may want to scatter off an object like Planet X,” he said via email.

At the AAS meeting last week, Sheppard said the likely alternative is that the orbits of these objects might reflect the primordial conditions of the Solar System, which formed more than 4.5 billion years ago. This makes them even more enticing for study, and Sheppard and his team will be keeping a close eye on V774104 to try and learn more. Nature News reported that the team plans to look for it again this week using the Magellan Telescopes in Chile, and then again in a year, to calculate its orbit and determine whether if it is an inner Oort cloud resident or an icy Kuiper Belt object.

Further reading: Nature, Armagh Planetarium,Centauri Dreams, Science.

A New “Mathematical” Definition Proposed for What Constitutes a Planet

In the current (heated) debate of what constitutes a planet, it seems everyone can agree at least one thing: The current definition put forth by the International Astronomical Union is actually quite vague and it really only applies to our own Solar System. So while the definition is unclear at best in our own neighborhood, it also doesn’t provide a framework for classifying the thousands of exo-worlds that are being discovered on almost a weekly basis.

Since math has been dubbed “the language of the Universe” it seems rather fitting and logical to use arithmetic to help in framing a better definition for planethood.

This week, UCLA professor Jean-Luc Margot has proposed a simple mathematical test that can be used to separate planets from other bodies like dwarf planets and minor planets. He says his new system is easy.

“One should not need a teleportation device to decide whether a newly discovered object is a planet,” Margot said.

The new approach would use estimates of the star’s mass and the planet’s mass and orbital period. Since the IAU’s definition is based primarily on the ability of a planet to “clear its orbit,” (whether it can accumulate or dominate small bodies in its orbital neighborhood), Margot’s test narrows this down to a specific timeframe of determining whether a body can clear a specific region around its orbit.

“A simple metric can be used to determine whether a planet or exoplanet can clear its orbital zone during a characteristic time scale, such as the lifetime of the host star on the main sequence,” Margot writes in his paper. “This criterion requires only estimates of star mass, planet mass, and orbital period, making it possible to immediately classify 99% of all known exoplanets.”

Under these criteria, all 8 planets and all classifiable exoplanets would be classified as planets. It also keeps the distinction between planets and dwarf planets. Some have pointed out that Margot’s criteria would make our Moon a planet. But, as Margot told Universe Today, that’s not necessarily so. “It really depends on how the IAU decides to define satellites and if or how they decide to define double planets,” he said.

Margot says his definition would be useful in generalizing and simplifying the definition of a planet, and that the information for applying this for exoplanets is easily obtained with Earth- or space-based telescopes.

“The disparity between planets and non-planets is striking,” Margot said. “The sharp distinction suggests that there is a fundamental difference in how these bodies formed, and the mere act of classifying them reveals something profound about nature.”

Margot also found that bodies that can clear their orbits — and therefore qualify as planets — are typically spherical.

“Because a quantitative orbit-clearing criterion can be applied to all planets and exoplanets,” Margot writes, “it is possible to extend the 2006 IAU planet definition to stars other than the Sun and to remove any possible ambiguity about what it means to clear an orbital zone.”

Margot presented his proposal at the annual meeting of the AAS’s Division for Planetary Sciences. It is not known whether the new approach will be considered by the IAU.

Further reading: Margot’s paper, UCLA press release

Dawn Starts Steep Descent to Most Dazzling Orbit of Ceres

The most dazzling views ever seen of dwarf planet Ceres and its mysterious bright spots are what’s on tap by year’s end as NASA’s amazing Dawn spacecraft starts a gradual but steep descent over the next two months to its lowest and final orbit around the bizarre icy body.

Engineers at NASA’s Jet Propulsion Laboratory (JPL) successfully fired up the probes exotic ion propulsion system to begin lowering Dawn’s orbital altitude to less than a quarter of what it has been for the past two months of intense mapping operations.

On Oct. 23, Dawn began a seven-week-long dive that uses ion thruster #2 to reduce the spacecrafts vantage point from 915 miles (1,470 kilometers) at the High Altitude Mapping Orbit (HAMO) down to less than 235 miles (380 kilometers) above Ceres at the Low Altitude Mapping Orbit (LAMO).

Dawn is slated to arrive at LAMO by mid-December, just in time to begin delivering the long awaiting Christmas treats.

Ceres has absolutely tantalized researchers far beyond their wildest expectations.

When Dawn arrives at LAMO it will be the culmination of an eight year interplanetary voyage that began with a blastoff on September 27, 2007 by a United Launch Alliance (ULA) Delta II Heavy rocket from Space Launch Complex-17B (SLC-17B) at Cape Canaveral Air Force Station, Florida.

LAMO marks Dawn’s fourth, lowest and final science orbit at Ceres where the highest resolution observations will be gathered and images from the framing camera will achieve a resolution of 120 feet (35 meters) per pixel.

Dawn’s low altitude mapping orbit LAMO. This shows how the orbit naturally shifts slightly (relative to the sun) during the three months of LAMO, starting in blue and ending in red. The spacecraft completes each revolution in 5.5 hours, and Ceres rotates in 9.1 hours, so Dawn will be able to view the entire surface. Credit: NASA/JPL
Dawn’s low altitude mapping orbit LAMO. This shows how the orbit naturally shifts slightly (relative to the sun) during the three months of LAMO, starting in blue and ending in red. The spacecraft completes each revolution in 5.5 hours, and Ceres rotates in 9.1 hours, so Dawn will be able to view the entire surface. Credit: NASA/JPL

At LAMO, researchers hope to finally resolve the enduring mystery of the nature of the bright spots that have intrigued science and the general public since they were first glimpsed clearly early this year as Dawn was on its final approach to Ceres.

Dawn arrived in orbit this past spring on March 6, 2015.

This image was taken by NASA's Dawn spacecraft of dwarf planet Ceres on Feb. 19 from a distance of nearly 29,000 miles (46,000 km). It shows that the brightest spot on Ceres has a dimmer companion, which apparently lies in the same basin. See below for the wide view. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This image was taken by NASA’s Dawn spacecraft of dwarf planet Ceres on Feb. 19 from a distance of nearly 29,000 miles (46,000 km). It shows that the brightest spot on Ceres has a dimmer companion, which apparently lies in the same basin. See below for the wide view. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The science team has just released a new mosaic of the brightest spots on Ceres found at Occator crater and the surrounding terrain – see above.

The images were taken from the HAMO altitude of 915 miles (1,470 kilometers) during the first of six mapping cycles. They have a resolution of 450 feet (140 meters) per pixel.

Occator measures about 60 miles (90 kilometers) across and 2 miles (4 kilometers) deep.

This image, made using images taken by NASA's Dawn spacecraft during the mission's High Altitude Mapping Orbit (HAMO) phase, shows Occator crater on Ceres, home to a collection of intriguing bright spots.  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This image, made using images taken by NASA’s Dawn spacecraft during the mission’s High Altitude Mapping Orbit (HAMO) phase, shows Occator crater on Ceres, home to a collection of intriguing bright spots. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Because the spots are so bright they are generally overexposed. Therefore the team took two sets of images, with shorter and longer exposure times, to maximize the details of the interior of Occator.

“This view uses a composite of two images of Occator: one using a short exposure that captures the detail in the bright spots, and one where the background surface is captured at normal exposure.”

The bright spots at Occator crater remain the biggest Cerean mystery.

So far the imagery and other science data may point to evaporation of salty water from the interior as the source of the bright spots.

“Occasional water leakage on to the surface could leave salt there as the water would sublime,” Prof. Chris Russell, Dawn principal investigator told Universe Today exclusively.

“The big picture that is emerging is that Ceres fills a unique niche.”

“Ceres fills a unique niche between the cold icy bodies of the outer solar system, with their rock hard icy surfaces, and the water planets Mars and Earth that can support ice and water on their surfaces,” Russell, of the University of California, Los Angeles, told me.

Dawn has peeled back Ceres secrets as the spacecraft orbits lower and lower. Detailed measurements gathered to date have yielded global mineral and topographic maps from HAMO with the best resolution ever as the science team painstakingly stitched together the probes spectral and imaging products.

And the best is yet to come at LAMO.

At HAMO, Dawn’ instruments, including the Framing Camera and Visible and Infrared Spectrometer (VIR) were aimed at slightly different angles in each mapping cycle allowing the team to generate stereo views and construct 3-D maps.

“The emphasis during HAMO is to get good stereo data on the elevations of the surface topography and to get good high resolution clear and color data with the framing camera,” Russell explained.

This view from NASA's Dawn spacecraft is a color-coded topographic map of Occator crater on Ceres. Blue is the lowest elevation, and brown is the highest. The crater, which is home to the brightest spots on Ceres, is approximately 56 miles (90 kilometers wide).  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This view from NASA’s Dawn spacecraft is a color-coded topographic map of Occator crater on Ceres. Blue is the lowest elevation, and brown is the highest. The crater, which is home to the brightest spots on Ceres, is approximately 56 miles (90 kilometers wide). Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn is Earth’s first probe in human history to explore any dwarf planet, the first to explore Ceres up close and the first to orbit two celestial bodies.

The asteroid Vesta was Dawn’s first orbital target where it conducted extensive observations of the bizarre world for over a year in 2011 and 2012.

Ceres is a Texas-sized world, ranks as the largest object in the main asteroid belt between Mars and Jupiter, and may have a subsurface ocean of liquid water that could be hospitable to life.

This map-projected view of Ceres was created from images taken by NASA's Dawn spacecraft during its high-altitude mapping orbit, in August and September, 2015.  This color coded map can provide valuable insights into the mineral composition of the surface, as well as the relative ages of surface features.  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This map-projected view of Ceres was created from images taken by NASA’s Dawn spacecraft during its high-altitude mapping orbit, in August and September, 2015. This color coded map can provide valuable insights into the mineral composition of the surface, as well as the relative ages of surface features. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The mission is expected to last until at least March 2016, and possibly longer, depending upon fuel reserves.

“It will end some time between March and December,” Dr. Marc Rayman, Dawn’s chief engineer and mission director based at NASA’s Jet Propulsion Laboratory, Pasadena, California, told Universe Today.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

Dawn at Ceres
An artist’s conception shows NASA’s Dawn spacecraft flying above Ceres. This view incorporates actual imagery from the Dawn mission. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Thousands of Pits Punctuate Pluto’s Forbidding Plains in Latest Photos

A brand new batch of Pluto and Charon photos showed up today on the New Horizons LORRI (LOng-Range Reconnaissance Imager) site. The photos were taken during the close flyby of the system on July 14, 2015 and show rich detail including craters and parallel cracks on Charon and thousands of small pits punctuating Pluto’s nitrogen ice landscape. Have at ’em!

This wider view shows the textured surface of Pluto's icy plains riddled with small pits. It almost looks like the dark areas in the sinuous channels between the mounds were once covered with frost or ice that has since sublimated away. They look similar to the polar regions on Mars where carbon dioxide frost burns off in the spring to reveal darker material beneath. Credit: NASA/JHUAPL/SwRI
This wider view shows the snakeskin-like textured surface of Pluto’s icy plains riddled with small pits. It almost looks like the dark areas in the sinuous channels between the mounds were once covered with frost or ice that has since sublimated away. They look similar to the polar regions on Mars where carbon dioxide frost burns off in the spring to reveal darker material beneath. Credit: NASA/JHUAPL/SwRI

The first couple images feature the region informally known as Sputnik Planum. According to a release from NASA today, scientists think the region is composed of volatile ices such as solid nitrogen. They theorize that the pits and troughs – typically hundreds of meters across and tens of meters deep – are possibly formed by sublimation or evaporation of these ices in Pluto’s thin atmosphere. Still, their curious shapes and alignments remain a mystery. Adding to the intrigue is that even when seen up close, no impact craters are visible, testifying to the icy plain’s extreme geologic youth.

By the way, there are more images at the LORRI link at top. I picked a representative selection but I encourage you to visit and explore.

Now that's what I call getting a photo in low light. Sunlight scrapes across rugged mountains as well as highlight the ubiquitous pits. Credit:
Now that’s what I call getting a photo in low light. Sunlight scrapes across rugged mountains as well as highlight the ubiquitous pitted terrain. Credit: NASA/JHUAPL/SwRI
Life's definitely the pits on Pluto's Tombaugh Regio. This photo shows the fainter "ghost" pits well. Is ice filling them in or are we seeing the start of a pit's formation? Credit:
Life’s definitely the pits on Pluto’s Tombaugh Regio. This photo shows the fainter “ghost” pits well. Is ice filling them in or are we seeing the beginning of a pit’s formation? Credit: NASA/JHUAPL/SwRI
A fine view of Pluto's largest moon Charon and its vast canyon system. Credit:
A fine view of Pluto’s largest moon Charon and its vast canyon system. Credit: NASA/JHUAPL/SwRI
Looking over Charon's dark north polar region, the border of which is highlighted by several beautiful rayed craters. Not that it's necessarily related, but the dark spot reminds me of a lunar mare or sea. On the moon, cracks in the crust allowed lava to fill gigantic basins to create the maria. Could material from beneath Charon have bubbled up to fill an ancient impact? Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Looking over Charon’s dark north polar region, the border of which is highlighted by several beautiful rayed craters. Not that it’s necessarily related, but the dark spot reminds me of a lunar mare or sea. On the moon, cracks in the crust allowed lava to fill gigantic basins to create the maria. Could material from beneath Charon have bubbled up to fill an ancient impact? Credit: NASA/JHUAPL/SwRI
Speaking of the Moon, these cracks resembles lunar rills, some of which formed through faulting / fracturing and others as conduits for lava flows. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Speaking of the Moon, the large cracks at left resemble lunar rills, some of which formed through faulting / fracturing and others as conduits for lava flows. The multiple, fine cracks  are interesting. Credit: NASA/JHUAPL/SwRI
Splendid rayed crater, each with its own set of tones. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Splendid rayed crater with an interesting contrast between dark and light ejecta. Credit: NASA/JHUAPL/SwRI
A busy region on Charon, the meeting place of different terrains. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
A busy region on Charon, the meeting place of different terrains. Credit: NASA/JHUAPL/SwRI

 

Scientists Tantalized as Dawn Yields Global Mineral and Topographic Maps of Ceres

Slowly but surely the mysteries of dwarf planet Ceres are being peeled back layer by layer as NASA’s Dawn spacecraft orbits lower and lower and gathers detailed measurements that have now yielded global mineral and topographic maps, tantalizing researchers with the best resolution ever.

The Dawn science team has been painstakingly stitching together the spectral and imaging products captured from the lowest orbit yet achieved into high resolution global maps of Ceres, released today Sept. 30, by NASA.

“Ceres continues to amaze, yet puzzle us, as we examine our multitude of images, spectra and now energetic particle bursts,” said Chris Russell, Dawn principal investigator at the University of California, Los Angeles, in a statement.

The color coded map above is providing researchers with valuable insights into the mineral composition of Ceres surface, as well as the relative ages of the surface features that were a near total mystery until Dawn arrived on March 6, 2015.

The false-color mineral map view combines images taken using infrared (920 nanometers), red (750 nanometers) and blue (440 nanometers) spectral filters.

“Redder colors indicate places on Ceres’ surface that reflect light strongly in the infrared, while bluish colors indicate enhanced reflectivity at short (bluer) wavelengths; green indicates places where albedo, or overall brightness, is strongly enhanced,” say officials.

“Scientists use this technique in order to highlight subtle color differences across Ceres, which would appear fairly uniform in natural color. This can provide valuable insights into the mineral composition of the surface, as well as the relative ages of surface features.”

Researchers say the mineral variations at Ceres “are more subtle than on Vesta, Dawn’s previous port of call.”

The asteroid Vesta was Dawn’s first orbital target and conducted extensive observations of the bizarre world for over a year in 2011 and 2012.

The Dawn team is meeting this week to review and publish the mission results so far at the European Planetary Science Conference in Nantes, France.

Dawn is Earth’s first probe in human history to explore any dwarf planet, the first to explore Ceres up close and the first to orbit two celestial bodies.

Ceres is a Texas-sized world, ranks as the largest object in the main asteroid belt between Mars and Jupiter, and may have a subsurface ocean of liquid water that could be hospitable to life.

This view from NASA's Dawn spacecraft is a color-coded topographic map of Occator crater on Ceres. Blue is the lowest elevation, and brown is the highest. The crater, which is home to the brightest spots on Ceres, is approximately 56 miles (90 kilometers wide).  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This view from NASA’s Dawn spacecraft is a color-coded topographic map of Occator crater on Ceres. Blue is the lowest elevation, and brown is the highest. The crater, which is home to the brightest spots on Ceres, is approximately 56 miles (90 kilometers wide). Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The newly released maps were created from data gathered at Dawn’s current science orbit, known as the High Altitude Mapping Orbit (HAMO) phase of the mission, during August and September.

At HAMO, Dawn is circling Ceres at an altitude of barely 915 miles (1,470 kilometers) above the heavily cratered surface.

“Dawn arrived in this third mapping orbit [HAMO] on Aug. 13. It began this third mapping phase on schedule on Aug. 17,” Dr. Marc Rayman, Dawn’s chief engineer and mission director based at NASA’s Jet Propulsion Laboratory, Pasadena, California, told Universe Today.

Each HAMO mapping orbit cycle lasts 11 days and consists of 14 orbits lasting 19 hours each. Ceres is entirely mapped during each of the 6 cycles. The third mapping cycle started on Sept. 9.

Dawn’ instruments, including the Framing Camera and Visible and Infrared Spectrometer (VIR) will be aimed at slightly different angles in each mapping cycle allowing the team to generate stereo views and construct 3-D maps.

“The emphasis during HAMO is to get good stereo data on the elevations of the surface topography and to get good high resolution clear and color data with the framing camera,” Russell told me.

“We are hoping to get lots of VIR IR data to help understand the composition of the surface better.”

“Dawn will use the color filters in its framing camera to record the sights in visible and infrared wavelengths,” notes Rayman.

The new maps at HAMO provide about three times better resolution than the images captured from its previous orbit in June, and nearly 10 times better than in the spacecraft’s initial orbit at Ceres in April and May.

This color-coded map from NASA's Dawn shows the highs and lows of topography on the surface of dwarf planet Ceres. It is labeled with names of features approved by the International Astronomical Union. The color scale extends about 5 miles (7.5 kilometers) below the reference surface in indigo to 5 miles (7.5 kilometers) above the reference surface in white.  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This color-coded map from NASA’s Dawn shows the highs and lows of topography on the surface of dwarf planet Ceres. It is labeled with names of features approved by the International Astronomical Union. The color scale extends about 5 miles (7.5 kilometers) below the reference surface in indigo to 5 miles (7.5 kilometers) above the reference surface in white. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The science team also released a new color-coded topographic map annotated with over a dozen Cerean feature names recently approved by the IAU.

“The names for features on Ceres are all eponymous for agricultural spirits, deities and festivals from cultures around the world. These include Jaja, after the Abkhazian harvest goddess, and Ernutet, after the cobra-headed Egyptian harvest goddess. A 12-mile (20-kilometer) diameter mountain near Ceres’ north pole is now called Ysolo Mons, for an Albanian festival that marks the first day of the eggplant harvest.”

The biggest Cerean mystery of all remains the nature of the bright spots at Occator crater. It’s still under analysis and the team released a new color coded topographic map.

The imagery and other science data may point to evaporation of salty water as the source of the bright spots.

“Occasional water leakage on to the surface could leave salt there as the water would sublime,” Russell told me.

“The big picture that is emerging is that Ceres fills a unique niche,” Prof. Chris Russell, Dawn principal investigator told Universe Today exclusively.

“Ceres fills a unique niche between the cold icy bodies of the outer solar system, with their rock hard icy surfaces, and the water planets Mars and Earth that can support ice and water on their surfaces,” said Russell.

“The irregular shapes of craters on Ceres are especially interesting, resembling craters we see on Saturn’s icy moon Rhea,” says Carol Raymond, Dawn’s deputy principal investigator based at NASA’s Jet Propulsion Laboratory, Pasadena, California. “They are very different from the bowl-shaped craters on Vesta.”

This image was taken by NASA's Dawn spacecraft of dwarf planet Ceres on Feb. 19 from a distance of nearly 29,000 miles (46,000 km). It shows that the brightest spot on Ceres has a dimmer companion, which apparently lies in the same basin. See below for the wide view. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This image was taken by NASA’s Dawn spacecraft of dwarf planet Ceres on Feb. 19 from a distance of nearly 29,000 miles (46,000 km). It shows that the brightest spot on Ceres has a dimmer companion, which apparently lies in the same basin. See below for the wide view. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Dawn was launched on September 27, 2007 by a United Launch Alliance (ULA) Delta II Heavy rocket from Space Launch Complex-17B (SLC-17B) at Cape Canaveral Air Force Station, Florida.

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

This image, made using images taken by NASA's Dawn spacecraft during the mission's High Altitude Mapping Orbit (HAMO) phase, shows Occator crater on Ceres, home to a collection of intriguing bright spots.  Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
This image, made using images taken by NASA’s Dawn spacecraft during the mission’s High Altitude Mapping Orbit (HAMO) phase, shows Occator crater on Ceres, home to a collection of intriguing bright spots. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA