Where New Horizons is

[neufer]

Look closely at the Layered atmosphere of Pluto and it really resembles the Rings of Saturn. The layers seem to spiral out from the surface. even the last visible layer appears to terminate above the arrow indicating where the first layer begins.

More likely, IMO: the layers were shot out by perihelion geysers
and have been slowly spiraling in to the surface ever since.

Could Pluto's rotational speed be sufficient to "throw Off" it's tenuous atmosphere and cause the apparent "Shelling Effect"

In relationship to its gravity Pluto's rotational centrifugal force
is 14 time weaker than Earth's rotational centrifugal force.

[orin stepanek]

Pluto's past!

http://www.nasa.gov/feature/new-horizon ... uto-s-past

[bystander]

New Horizons Fills Gap in Space Environment Observations
NASA | GSFC SVS | New Horizons | 2016 Apr 04

[c][youtube]https://www.youtube.com/watch?v=o-LVK5TuKcA[/youtube]Space environment data collected by New Horizons over a billion miles of its
journey to Pluto will play a key role in testing and improving models of the
space environment throughout the solar system. This visualization is one
example of such a model: It shows the simulated space environment out to
Pluto a few months before New Horizons’ closest approach.

Credits: NASA's Goddard Space Flight Center Scientific Visualization Studio
(GSFC SVS), the Space Weather Research Center (SWRC) and the Community-
Coordinated Modeling Center (CCMC), Enlil and Dusan Odstrcil (GMU)[/c][hr][/hr]

When NASA's New Horizons sped past Pluto on July 14, 2015, it took the best-ever pictures of the rocky world’s surface, giving us new insight into its geology, composition and atmosphere. These stunning images are the most famous result of New Horizons, but the spacecraft also sent back over three years’ worth of measurements of the solar wind – the constant flow of solar particles that the sun flings out into space – from a region that has been visited by only a few spacecraft.

This unprecedented set of observations give us a peek into an almost entirely unexplored part of our space environment – filling a crucial gap between what other missions see closer to the sun and what the Voyager spacecraft see further out. A new study to appear in The Astrophysical Journal Supplement lays out New Horizons’ observations of the solar wind ions that it encountered on its journey.

Not only does the New Horizons data provide new glimpses of the space environment of the outer solar system, but this information helps round out our growing picture of the sun’s influence on space, from near-Earth effects to the boundary where the solar wind meets interstellar space. The new data shows particles in the solar wind that have picked up an initial burst of energy, an acceleration boost that kicks them up just past their original speed. These particles may be the seeds of extremely energetic particles called anomalous cosmic rays. When these super-fast, energetic rays travel closer to Earth, they can pose a radiation hazard to astronauts. Further away, at lower energies, the rays are thought to play a role at shaping the boundary where the solar wind hits interstellar space – the region of our solar system that Voyager 2 is currently navigating and observing. ...

Multitasking New Horizons Observed Solar Wind Changes on Journey to Pluto
Southwest Research Institute | Solar Wind Around Pluto | 2016 Apr 05

SWAP data show that the tumultuous flow of solar particles becomes more uniform by the time the solar wind reaches Pluto

In addition to its history-making encounter with Pluto last July, the New Horizons spacecraft also recorded significant changes in how the solar wind behaves far from the Sun.

The Solar Wind Around Pluto (SWAP) instrument, operated by Southwest Research Institute (SwRI), collected three years’ worth of measurements before the July 15 Pluto flyby. Data showed that the tumultuous flow of solar particles, which in the inner solar system is structured by the interaction of fast and slow flows as well as eruptive events on the Sun, becomes more uniform by the time the solar wind has traversed the 3 billion miles to Pluto’s orbit. ...

New Horizons Solar Wind Around Pluto (SWAP) Observations of the Solar Wind From 11-33 AU - H. A. Elliott et al

• arXiv.org > astro-ph > arXiv:1601.07156 > 26 Jan 2016

[bystander]

Pluto's Interactions with the Solar Wind Are Unique
American Geophysical Union | 2016 May 04

[img3="Schematic diagram of Pluto’s interaction with the solar wind as inferred from SWAP observations along the trajectory of the New Horizons flyby. (Credit: AGU)"]http://news.agu.org/files/2016/05/image-2-1024x625.jpg[/img3][hr][/hr]

Pluto has some characteristics less like that of a comet and more like much larger planets, according to an analysis of Pluto’s unique interaction with the solar wind, scientists say.

Using data from an instrument aboard the New Horizons spacecraft gathered on its Pluto flyby in July 2015, scientists have observed the material coming off of Pluto and seen how it interacts with the solar wind, and found it completely new – and unexpected. ...

Space physicists say that they now have a treasure trove of information about how Pluto’s atmosphere interacts with the solar wind. Solar wind is the plasma, or charged particles, that spews off from the sun into the solar system at a supersonic 400 kilometers per second (1 million miles per hour), bathing planets, asteroids, comets and interplanetary space in a soup of mostly electrons and protons. ...

Previously, most researchers thought that Pluto was characterized more like a comet, which has a large region of gentle slowing of the solar wind, as opposed to the abrupt diversion solar wind encounters at a planet like Mars or Venus. Instead, like a car that’s part gas- and part battery-powered, Pluto is a hybrid, the researchers say. ...

Unique Pluto, solar wind interactions similar to those of larger planets
Princeton University | 2016 May 04

Pluto's Interaction with the Solar Wind - D. J. McComas et al

• Journal of Geophysical Research - Space Physics (online 04 May 2016) DOI: 10.1002/2016JA022599

Pluto’s interaction with its space environment: Solar wind, energetic particles, and dust - F. Bagenal et al

• Science 351(6279):aad9045 (18 Mar 2016) DOI: 10.1126/science.aad9045
  arXiv.org > astro-ph > arXiv:1605.00749 > 03 May 2016

[orin stepanek]

http://pluto.jhuapl.edu/Multimedia/Scie ... age_id=436
http://www.nasa.gov/feature/first-stell ... atmosphere

They keep learning more and more about Pluto!

[bystander]

New Horizons Collects First Science on a Post-Pluto Object
NASA | JHU-APL | SwRI | 2016 May 18

[c][attachment=0]KBO-deep_press_anno[1].gif[/attachment][/c][hr][/hr]

In April 2016, NASA's New Horizons spacecraft observed 1994 JR1, a 90-mile (145-kilometer) wide Kuiper Belt object (KBO) orbiting more than 3 billion miles (5 billion kilometers) from the sun, for the second time. Taken with the spacecraft’s Long Range Reconnaissance Imager (LORRI) on April 7-8 from a distance of about 69 million miles (111 million kilometers), the images shatter New Horizons' own record for the closest-ever views of this KBO in November 2015, when New Horizons detected JR1 from 170 million miles (280 million kilometers) away.

Combining the November 2015 and April 2016 observations allows scientists to pinpoint the location of JR1 to within 1,000 kilometers (about 600 miles), far better than any small KBO. The more accurate orbit also allows the science team to dispel a theory that JR1 is a quasi-satellite of Pluto.

From the closer vantage point of the April 2016 observations, the team also determined the object's rotation period, observing the changes in light reflected from JR1's surface to determine that it rotates once every 5.4 hours (or a JR1 day).

The observations are great practice for possible close-up looks at about 20 more ancient Kuiper Belt objects that may come in the next few years, should NASA approve an extended mission. New Horizons flew through the Pluto system on July 14, 2015, making the first close-up observations of Pluto and its family of five moons. The spacecraft is on course for an ultra-close flyby of another Kuiper Belt object, 2014 MU69, on Jan. 1, 2019.

[BMAONE23]

There is also an apparent object displaying motion in the opposite direction at the 3:00 position. It covers about 1/5th the distance in the opposite direction and is only just visible at the edge of the field of view in the second image

[Faye Kane-GirlBrain]

Hmm... you're right! I wonder what that is. But its retrograde motion makes it unlikely to be an orbiting object. Comet, maybe?

Anyone?

Beuller?

[Faye Kane-GirlBrain]

Would you guys PLEASE put the angular width of all images?

For all I can tell, this moving object is a star plunging into the galaxy's center. Or a LEO satellite. Or a bacterium looking for something yummy to eat. Or whatever.

-faye

[Chris Peterson]

Would you guys PLEASE put the angular width of all images?

For all I can tell, this moving object is a star plunging into the galaxy's center. Or a LEO satellite. Or a bacterium looking for something yummy to eat. Or whatever.

You can almost always get that kind of information by submitting an image to nova.astrometry.net. Doing so with this image gives:

Code: Select all

Center (RA, Dec):	(235.262, 12.210)
Center (RA, hms):	15h 41m 02.803s
Center (Dec, dms):	+12° 12' 37.093"
Size:	8.7 x 6.53 arcmin
Radius:	0.091 deg
Pixel scale:	0.51 arcsec/pixel
Orientation:	Up is 12.4 degrees E of N

What is interesting is that the pixel scale is exactly half that of the LORRI camera, suggesting that this image has been scaled up in size by a factor of two.

Here's an overlay with a higher resolution SDSS image.

[bystander]

Pluto's Heart: Like a Cosmic 'Lava Lamp'
NASA | JHU-APL | SwRI | New Horizons | 2016 Jun 01

[c][attachment=0]nh-mckinnon_etal_nature_cover_trimmed[1].jpg[/attachment][/c][hr][/hr]

Like a cosmic lava lamp, a large section of Pluto’s icy surface is being constantly renewed by a process called convection that replace older surface ices with fresher material.

Combining computer models with topographic and compositional data gathered by NASA’s New Horizons spacecraft last summer, New Horizons team members have determined the depth of this layer of solid nitrogen ice within Pluto's distinctive "heart" feature – a large plain informally known as Sputnik Planum – and how fast that ice is flowing. ...

Mission scientists used state-of-the-art computer simulations to show that the surface of Sputnik Planum is covered with icy, churning, convective "cells" 10 to 30 miles (16 to 48 kilometers) across, and less than one million years old. The findings offer additional insight into the unusual and highly active geology on Pluto and, perhaps, other bodies like it on the outskirts of the solar system. ...

McKinnon and colleagues believe the pattern of these cells stems from the slow thermal convection of the nitrogen-dominated ices that fill Sputnik Planum. A reservoir that’s likely several miles deep in some places, the solid nitrogen is warmed by Pluto’s modest internal heat, becomes buoyant and rises up in great blobs – like a lava lamp – before cooling off and sinking again to renew the cycle.

The computer models show that ice need only be a few miles deep for this process to occur, and that the convection cells are very broad. The models also show that these blobs of overturning solid nitrogen can slowly evolve and merge over millions of years. Ridges that mark where cooled nitrogen ice sinks back down can be pinched off and abandoned, resulting in Y- or X-shaped features in junctions where three or four convection cells once met. ...

Purdue Team Finds Convection Could Produce Pluto's Polygons
Purdue University | 2016 Jun 02

Convection in a volatile nitrogen-ice-rich layer drives Pluto’s geological vigour - William B. McKinnon et al

• Nature 534(7605):82 (02 Jun 2016) DOI: 10.1038/nature18289

Vigorous convection as the explanation for Pluto’s polygonal terrain - A. J. Trowbridge et al

• Nature 534(7605):79 (02 Jun 2016) DOI: 10.1038/nature18016

[bystander]

Secrets Revealed from Pluto's 'Twilight Zone'
NASA | JHU-APL | SwRI | New Horizons | 2016 Jun 02

[img3="Credits: NASA/JHUAPL/SwRI"]http://www.nasa.gov/sites/default/files ... eimage.jpg[/img3][hr][/hr]

NASA's New Horizons spacecraft took this stunning image of Pluto only a few minutes after closest approach on July 14, 2015. The image was obtained at a high phase angle -that is, with the sun on the other side of Pluto, as viewed by New Horizons. Seen here, sunlight filters through and illuminates Pluto's complex atmospheric haze layers. The southern portions of the nitrogen ice plains informally named Sputnik Planum, as well as mountains of the informally named Norgay Montes, can also be seen across Pluto's crescent at the top of the image.

Looking back at Pluto with images like this gives New Horizons scientists information about Pluto's hazes and surface properties that they can't get from images taken on approach. The image was obtained by New Horizons' Ralph/Multispectral Visual Imaging Camera (MVIC) approximately 13,400 miles (21,550 kilometers) from Pluto, about 19 minutes after New Horizons' closest approach. The image has a resolution of 1,400 feet (430 meters) per pixel. Pluto's diameter is 1,475 miles (2,374 kilometers).

The inset at top right shows a detail of Pluto's crescent, including an intriguing bright wisp (near the center) measuring tens of miles across that may be a discreet, low-lying cloud in Pluto's atmosphere; if so, it would be the only one yet identified in New Horizons imagery. This cloud - if that's what it is - is visible for the same reason the haze layers are so bright: illumination from the sunlight grazing Pluto's surface at a low angle. Atmospheric models suggest that methane clouds can occasionally form in Pluto's atmosphere. The scene in this inset is 140 miles (230 kilometers) across.

The inset at bottom right shows more detail on the night side of Pluto. This terrain can be seen because it is illuminated from behind by hazes that silhouette the limb. The topography here appears quite rugged, and broad valleys and sharp peaks with relief totaling 3 miles (5 kilometers) are apparent. This image, made from closer range, is much better than the lower-resolution images of this same terrain taken several days before closest approach. These silhouetted terrains therefore act as a useful "anchor point," giving New Horizons scientists a rare, detailed glimpse at the lay of the land in this mysterious part of Pluto seen at high resolution only in twilight. The scene in this inset is 460 miles (750 kilometers) wide.

[bystander]

The Jagged Shores of Pluto’s Highlands
NASA | JHU-APL | SwRI | New Horizons | 2016 Jun 09

[img3="Credits: NASA/JHUAPL/SwRI"]http://www.nasa.gov/sites/default/files ... 09-sml.jpg[/img3][hr][/hr]

This enhanced color view from NASA’s New Horizons spacecraft zooms in on the southeastern portion of Pluto’s great ice plains, where at lower right the plains border rugged, dark highlands informally named Krun Macula. (Krun is the lord of the underworld in the Mandaean religion, and a ‘macula’ is a dark feature on a planetary surface.)

Pluto is believed to get its dark red color from tholins, complex molecules found across much of the surface. Krun Macula rises 1.5 miles (2.5 kilometers) above the surrounding plain – informally named Sputnik Planum – and is scarred by clusters of connected, roughly circular pits that typically reach between 5 and 8 miles (8 and 13 kilometers) across, and up to 1.5 miles (2.5 kilometers) deep.

At the boundary with Sputnik Planum, these pits form deep valleys reaching more than 25 miles (40 kilometers) long, 12.5 miles (20 kilometers) wide and almost 2 miles (3 kilometers) deep – almost twice as deep as the Grand Canyon in Arizona – and have floors covered with nitrogen ice. New Horizons scientists think these pits may have formed through surface collapse, although what may have prompted such a collapse is a mystery.

This scene was created using three separate observations made by New Horizons in July 2015. The right half of the image is composed of 260 feet- (80 meter-) per-pixel data from the Long Range Reconnaissance Imager (LORRI), obtained at 9,850 miles (15,850 kilometers) from Pluto, about 23 minutes before New Horizons’ closest approach. The left half is composed of 410 feet- (125 meter-) per-pixel LORRI data, obtained about six minutes earlier, with New Horizons 15,470 miles (24,900 kilometers) from Pluto.

These data respectively represent portions of the highest- and second-highest-resolution observations obtained by New Horizons in the Pluto system. The entire scene was then colorized using 2,230 feet- (680 meter-) per-pixel data from New Horizons’ Ralph/Multispectral Visual Imaging Camera (MVIC), obtained at 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before closest approach.

[bystander]

New Data Compare, Contrast Pluto’s Icy Moons
NASA | JHU-APL | SwRI | New Horizons | 2016 Jun 16

[img3="Pluto’s moons Charon, Nix and Hydra. Charon and Nix were imaged in color by NASA’s New Horizons spacecraft, but Hydra was not. Credits: NASA/JHUAPL/SwRI"]http://www.nasa.gov/sites/default/files ... posite.jpg[/img3][img3="A comparison of the compositional spectra of Pluto’s moons Charon, Nix and Hydra to pure water ice. Nix’s surface displays the deepest water-ice spectral features seen among Pluto’s three satellites – Charon, Nix and Hydra – for which New Horizons obtained surface spectra. Credits: NASA/JHUAPL/SwRI"]http://www.nasa.gov/sites/default/files ... posite.jpg[/img3][hr][/hr]

A newly downlinked spectral observation of Pluto’s moon Nix from NASA’s New Horizons spacecraft provides compelling evidence that its surface is covered in water ice, similar to what the New Horizons team discovered recently for another of Pluto’s small satellites, Hydra. This new result provides further clues about the formation of Pluto’s satellite system.

With this observation by New Horizons’ LEISA – the compositional spectral imager aboard the spacecraft – mission scientists also are piecing together a more detailed picture of Pluto's system of four small, outer moons (Styx, Nix, Kerberos and Hydra).

The deeper spectral features on Nix seen in the graph above are a signature of water ice that is relatively coarse-grained and pure, because the shape and depth of water-ice absorption depends on the size and purity of the icy grains on the surface. Scattering from smaller, or less pure, icy grains tends to wash out spectral absorption features, making them shallower. ...

The difference in the depths of the water ice absorption features in the Nix and Hydra spectra raises new questions. Specifically, the science team is puzzling over why Nix and Hydra apparently have different ice textures on their surfaces, despite their similar sizes. Another mystery resulting from the Pluto flyby data is why Hydra’s surface reflectivity at visible wavelengths is higher than Nix’s – a New Horizons result published in March in the journal Science – even though Nix’s surface appears to be icier, implying higher reflectivity at visible wavelengths.

The LEISA Nix observation was captured on July 14, 2015, from a range of 37,000 miles (60,000 kilometers), resulting in a spatial resolution of about 2.3 miles per pixel (3.7 kilometers per pixel).

[bystander]

Case Bolstered for a Present-Day Subsurface Ocean on Pluto
Brown University | 2016 June 21

An updated thermal model for Pluto suggests that liquid water beneath the dwarf planet’s ice shell may not be frozen yet.

[img3="The New Horizons spacecraft spied extensional faults on Pluto, a sign that the dwarf planet has undergone a global expansion possibly due to the slow freezing of a subsurface ocean. A new analysis by Brown University scientists bolsters that idea, and suggests that ocean is likely still there today. (Credit: NASA/JHUAPL/SwRI)"]https://news.brown.edu/files/styles/pan ... k=CCm4WOaI[/img3][hr][/hr]

When the NASA’s New Horizons spacecraft buzzed by Pluto last year, it revealed tantalizing clues that the dwarf planet might have — or had at one time — a liquid ocean sloshing around under its icy crust. According to a new analysis led by a Brown University Ph.D. student, such an ocean likely still exists today.

The study, which used a thermal evolution model for Pluto updated with data from New Horizons, found that if Pluto’s ocean had frozen into oblivion millions or billions of years ago, it would have caused the entire planet to shrink. But there are no signs of a global contraction to be found on Pluto’s surface. On the contrary, New Horizons showed signs that Pluto has been expanding. ...

Pluto’s Subsurface Ocean May Likely Exist Today
Planetary Science Institute | 2016 June 21

Recent Tectonic Activity on Pluto Driven by Phase Changes in the Ice Shell - Noah P. Hammond, Amy C. Barr, Edgar M. Parmentier

• Geophysical Research Letters (online 15 June 2016) DOI: 10.1002/2016GL069220
  arXiv.org > astro-ph > arXiv:1606.04840 > 15 Jun 2016 (v1), 20 Jun 2016 (v2)

[Ann]

Click to view full size image

Sputnik Planum at left, Tombaugh Regio at right,
Challenger Colles at upper right.

J. Kelly Beatty wrote in the June issue of Sky & Telescope:

Within days of New Horizons historic flyby of of Pluto last July 14th, mission scientists released snapshots showing unexpectedly tall mountains partially rimming a vast and very flat plain.The plain, informally named Sputnik Planum, is dominated by frozen molecular nitrogen (N₂ and some frozen carbon monoxide (CO), wheras the the surrounding uplands are mostly frozen water.

But recently the team unveiled an image of Sputnik Planum that reveals clusters of hills that stick up through the plain's surface.The plain is made up of large, polygonal slabs, and the hills, which are up to a few kilometers across, appears to be bobbing along in the icy floes and getting trapped where the slabs meet.

Perhaps the mysterious hills are are fragments of water ice from the mountains that partially surround Sputnik Planum. Interestingly, these water-ice "islands" appear to be analogous to ocean-going icebergs here on Earth...

Interestingly, one large cluster, nicknamed Challenger Colles ... measure 60 by 35 km (37 by 22 miles). This grouping isn't out in the middle of Sputnik Planum but rather located near its eastern margin, near the peaks of central Tombaugh Regio (another informal name). So perhaps these hills became "beached" once the nitrogen ice became too shallow.

Ann

[orin stepanek]

http://www.nasa.gov/feature/a-super-gra ... oon-charon

Wow! That is one big Chasm!

[orin stepanek]

Click to play embedded YouTube video.

http://pluto.jhuapl.edu/common/content/ ... A_lres.mp4

Pluto aproach!

[orin stepanek]

Latest from New Horizons!
http://www.nasa.gov/feature/pluto-s-met ... f-darkness

[bystander]

Pluto 'Paints' its Largest Moon Red
NASA | JHU APL | SwRI | New Horizons | 2016 Sep 14

[img3="NASA's New Horizons spacecraft captured this high-resolution, enhanced color view of Pluto’s largest moon, Charon, just before closest approach on July 14, 2015. The image combines blue, red and infrared images taken by the spacecraft's Ralph/Multispectral Visual Imaging Camera (MVIC); the colors are processed to best highlight the variation of surface properties across Charon. Scientists have learned that reddish material in the north (top) polar region – informally named Mordor Macula – is chemically processed methane that escaped from Pluto’s atmosphere onto Charon. Charon is 754 miles (1,214 km) across; this image resolves details as small as 1.8 miles (2.9 km). Credits: NASA/JHUAPL/SwRI"]http://www.nasa.gov/sites/default/files ... charon.jpg[/img3][hr][/hr]

In June 2015, when the cameras on NASA’s approaching New Horizons spacecraft first spotted the large reddish polar region on Pluto’s largest moon, Charon, mission scientists knew two things: they’d never seen anything like it elsewhere in our solar system, and they couldn’t wait to get the story behind it.

Over the past year, after analyzing the images and other data that New Horizons has sent back from its historic July 2015 flight through the Pluto system, the scientists think they’ve solved the mystery. As they detail this week in the international scientific journal Nature, Charon’s polar coloring comes from Pluto itself – as methane gas that escapes from Pluto’s atmosphere and becomes “trapped” by the moon’s gravity and freezes to the cold, icy surface at Charon’s pole. This is followed by chemical processing by ultraviolet light from the sun that transforms the methane into heavier hydrocarbons and eventually into reddish organic materials called tholins.

"Who would have thought that Pluto is a graffiti artist, spray-painting its companion with a reddish stain that covers an area the size of New Mexico?" asked Will Grundy, a New Horizons co-investigator from Lowell Observatory in Flagstaff, Arizona, and lead author of the paper. "Every time we explore, we find surprises. Nature is amazingly inventive in using the basic laws of physics and chemistry to create spectacular landscapes."

The team combined analyses from detailed Charon images obtained by New Horizons with computer models of how ice evolves on Charon's poles. Mission scientists had previously speculated that methane from Pluto's atmosphere was trapped in Charon's north pole and slowly converted into the reddish material, but had no models to support that theory. ...

The formation of Charon’s red poles from seasonally cold-trapped volatiles - W. M. Grundy et al

• Nature (online 14 Sep 2016) DOI: 10.1038/nature19340

[Ann]

Ah! I was really wondering!

So the strong color difference between Pluto and Charon boils down to the fact that Pluto has a methane atmosphere, but Charon doesn't, except on its north polar cap? Or the atmosphere that Charon has siphoned off of Pluto only freezes at Charon's poles, where it can be color-changed by ultraviolet light from the Sun?

Ann

[bystander]

X-ray Detection Sheds New Light on Pluto
NASA | JHU-APL | Chandra | CfA | New Horizons | 2016 Sep 14

[img3="The first detection of Pluto in X-rays has been made using NASA’s Chandra X-ray Observatory in conjunction with observations from NASA’s New Horizon spacecraft.
Credits: X-ray: NASA/CXC/JHUAPL/R.McNutt et al; Optical: NASA/JHUAPL"]https://www.nasa.gov/sites/default/file ... handra.jpg[/img3][hr][/hr]

Scientists using NASA’s Chandra X-ray Observatory have made the first detections of X-rays from Pluto. These observations offer new insight into the space environment surrounding the largest and best-known object in the solar system’s outermost regions.

While NASA’s New Horizons spacecraft was speeding toward and beyond Pluto, Chandra was aimed several times on the dwarf planet and its moons, gathering data on Pluto that the missions could compare after the flyby. Each time Chandra pointed at Pluto – four times in all, from February 2014 through August 2015 – it detected low-energy X-rays from the small planet. ...

The team recently published its findings online in the journal Icarus. The report details what Lisse says was a somewhat surprising detection given that Pluto – being cold, rocky and without a magnetic field – has no natural mechanism for emitting X-rays. But Lisse, having also led the team that made the first X-ray detections from a comet two decades ago, knew the interaction between the gases surrounding such planetary bodies and the solar wind – the constant streams of charged particles from the sun that speed throughout the solar system ­– can create X-rays.

New Horizons scientists were particularly interested in learning more about the interaction between the gases in Pluto’s atmosphere and the solar wind. The spacecraft itself carries an instrument designed to measure that activity up-close – the aptly named Solar Wind Around Pluto (SWAP) – and scientists are using that data to craft a picture of Pluto that contains a very mild, close-in bowshock, where the solar wind first “meets” Pluto (similar to a shock wave that forms ahead of a supersonic aircraft) and a small wake or tail behind the planet.

The immediate mystery is that Chandra’s readings on the brightness of the X-rays are much higher than expected from the solar wind interacting with Pluto’s atmosphere. ...

The Puzzling Detection of X-rays from Pluto by Chandra - C.M. Lisse et al

• Icarus (online 27 July 2016)

[bystander]

Pluto's 'Heart' Sheds Light on a Possible Buried Ocean
Brown University | 2016 Sep 23

[img3="Pluto's famous "heart," half of which was created by an ancient impact, offers clues about a possible subsurface ocean. Credit: NASA/JHUAPL/SwRI"]https://www.nasa.gov/sites/default/file ... _color.jpg[/img3][hr][/hr]

Ever since NASA’s New Horizons spacecraft flew by Pluto last year, evidence has been mounting that the dwarf planet may have a liquid ocean beneath its icy shell. Now, by modeling the impact dynamics that created a massive crater on Pluto’s surface, a team of researchers has made a new estimate of how thick that liquid layer might be.

The study, led by Brown University geologist Brandon Johnson and published in Geophysical Research Letters, finds a high likelihood that there’s more than 100 kilometers of liquid water beneath Pluto’s surface. The research also offers a clue about the composition of that ocean, suggesting that it likely has a salt content similar to that of the Dead Sea.

“Thermal models of Pluto’s interior and tectonic evidence found on the surface suggest that an ocean may exist, but it’s not easy to infer its size or anything else about it,” said Johnson, who is an assistant professor in Brown’s Department of Earth, Environmental and Planetary Sciences. “We’ve been able to put some constraints on its thickness and get some clues about composition.”

The research focused on Sputnik Planum, a basin 900 kilometers across that makes up the western lobe the famous heart-shaped feature revealed during the New Horizons flyby. The basin appears to have been created by an impact, likely by an object 200 kilometers across or larger. ...

Formation of the Sputnik Planum Basin and the Thickness of Pluto's Subsurface Ocean - Brandon C. Johnson et al

• Geophysical Research Letters (online 19 Sep 2016) DOI: 10.1002/2016GL070694

[orin stepanek]

Just so you know! http://www.seeplutonow.com/

[bystander]

Possible Clouds on Pluto, Next Target Is Reddish
NASA | JHU-APL | SwRI | New Horizons | 2016 Oct 18

[img3="Artist's impression of NASA’s New Horizons spacecraft encountering a Kuiper Belt object, as part of an extended mission after the spacecraft’s July 2015 Pluto flyby. New Horizons is set to fly past 2014 MU69 – a KBO currently about a billion miles (1.6 billion kilometers) beyond Pluto – on Jan. 1, 2019. Recent data from the Hubble Space Telescope suggests 2014 MU69 has a reddish hue, even redder than Pluto. The object is the smallest KBO to have its surface properties measured."]http://www.nasa.gov/sites/default/files ... ounter.jpg[/img3]

[img3="Partly Cloudy on Pluto? Pluto’s present, hazy atmosphere is almost entirely free of clouds, though scientists from NASA’s New Horizons mission have identified some cloud candidates after examining images taken by the New Horizons Long Range Reconnaissance Imager and Multispectral Visible Imaging Camera, during the spacecraft’s July 2015 flight through the Pluto system. All are low-lying, isolated small features—no broad cloud decks or fields – and while none of the features can be confirmed with stereo imaging, scientists say they are suggestive of possible, rare condensation clouds."]http://www.nasa.gov/sites/default/files ... npluto.jpg[/img3]

[img3="Scientists from NASA’s New Horizons mission have spotted signs of long run-out landslides on Pluto’s largest moon, Charon. This image of Charon’s informally named Serenity Chasma was taken by New Horizons’ Long Range Reconnaissance Imager (LORRI) on July 14, 2015, from a distance of 48,912 miles (78,717 kilometers). Arrows mark indications of landslide activity."]http://www.nasa.gov/sites/default/files ... otated.jpg[/img3]

Image Credits: NASA/JHUAPL/SwRI