Sunglint Off of Titan's Kraken Mare

This near-infrared, color mosaic from NASA's Cassini spacecraft shows the sun glinting off of Titan's north polar seas. While Cassini has captured, separately, views of the polar seas (see PIA17470) and the sun glinting off of them (see PIA12481 and PIA18433) in the past, this is the first time both have been seen together in the same view.

The sunglint, also called a specular reflection, is the bright area near the 11 o'clock position at upper left. This mirror-like reflection, known as the specular point, is in the south of Titan's largest sea, Kraken Mare, just north of an island archipelago separating two separate parts of the sea.

This particular sunglint was so bright as to saturate the detector of Cassini's Visual and Infrared Mapping Spectrometer (VIMS) instrument, which captures the view. It is also the sunglint seen with the highest observation elevation so far -- the sun was a full 40 degrees above the horizon as seen from Kraken Mare at this time -- much higher than the 22 degrees seen in PIA18433. Because it was so bright, this glint was visible through the haze at much lower wavelengths than before, down to 1.3 microns.

The southern portion of Kraken Mare (the area surrounding the specular feature toward upper left) displays a "bathtub ring" -- a bright margin of evaporate deposits -- which indicates that the sea was larger at some point in the past and has become smaller due to evaporation. The deposits are material left behind after the methane & ethane liquid evaporates, somewhat akin to the saline crust on a salt flat.

The highest resolution data from this flyby -- the area seen immediately to the right of the sunglint -- cover the labyrinth of channels that connect Kraken Mare to another large sea, Ligeia Mare. Ligeia Mare itself is partially covered in its northern reaches by a bright, arrow-shaped complex of clouds. The clouds are made of liquid methane droplets, and could be actively refilling the lakes with rainfall.

The view was acquired during Cassini's August 21, 2014, flyby of Titan, also referred to as "T104" by the Cassini team.

The view contains real color information, although it is not the natural color the human eye would see. Here, red in the image corresponds to 5.0 microns, green to 2.0 microns, and blue to 1.3 microns. These wavelengths correspond to atmospheric windows through which Titan's surface is visible. The unaided human eye would see nothing but haze, as in PIA12528.

Image credit: NASA/JPL-Caltech/University of Arizona/University of Idaho

Note: For more information, see PIA18433: Sunglint on a Hydrocarbon Lake and Cassini Sees Sunny Seas on Titan.

Artist’s Impression of the Double-Star System GG Tauri-A

This artist’s impression shows the dust and gas around the double star system GG Tauri-A. Researchers using ALMA have detected gas in the region between two discs in this binary system. This may allow planets to form in the gravitationally perturbed environment of the binary. Half of Sun-like stars are born in binary systems, meaning that these findings will have major consequences for the hunt for exoplanets.

Illustration credit: ESO/L. Calçada

Note: For more information, see Planet-Forming Lifeline Discovered in a Binary Star System.

Perseus and Virgo Galactic Clusters

Perseus Cluster and Virgo Cluster: Two galaxy clusters about 250 million and 50 million light years away respectively.

Chandra observations of the Perseus and Virgo galaxy clusters have provided direct evidence that turbulence is helping to prevent stars from forming there. These new results could answer along-standing question about how these galaxy clusters keep their enormous reservoirs of hot gas from cooling down to form stars. Scientists targeted Perseus and Virgo because they are both extremely large and relatively bright, thus providing an opportunity to see details that would be very difficult to detect in other clusters.

Image credit: NASA/CXC/Stanford/I.Zhuravleva et al.

Note: For more information, see Perseus Cluster and Virgo Cluster: NASA's Chandra Observatory Identifies Impact of Cosmic Chaos on Star Birth.

Exocomets Around Beta Pictoris

This artist’s impression shows exocomets orbiting the star Beta Pictoris. Astronomers analyzing observations of nearly 500 individual comets made with the HARPS instrument at ESO’s La Silla Observatory have discovered two families of exocomets around this nearby young star. The first consists of old exocomets that have made multiple passages near the star. The second family, shown in this illustration, consists of younger exocomets on the same orbit, which probably came from the recent breakup of one or more larger objects.

Illustration credit: ESO/L. Calçada

Note: For more information, see Two Families of Comets Found Around Nearby Star.

Comet 67P/Churyumov-Gerasimenko's Jets

This image of 67P/Churyumov-Gerasimenko was taken by the Optical, Spectroscopic, and Infrared Remote Imaging System, Rosetta's main onboard scientific imaging system, on September 10, 2014. Jets of cometary activity can be seen along almost the entire body of the comet.

Image credit: ESA/Rosetta/MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Note: For more information, see PIA18835: Rosetta Comet Spreads its Jets, Comet activity – 10 September 2014, Rosetta's Comet Scrambling Its Jets(JPL), and Rosetta Comet Scrambles its Jets (NASA Science News).

Six Images by Chandra

Chandra Archive Collection: Six images that combine Chandra data with those from other telescopes.

With the passing of Chandraʼs 15th anniversary, the Chandra Data Archive, which houses all of the missionʼs data, continues to grow each successive year. These images – that include a wide range of astronomical objects -- combine X-rays from Chandraʼs archive with data from other telescopes. This technique of creating “multi-wavelength” images allows scientists and the public to see how X-rays fit with data of other types of light, such as optical, radio, and infrared.

PSR B1509-58 (upper left)
Pareidolia is the psychological phenomenon where people see recognizable shapes in clouds, rock formations, or otherwise unrelated objects or data. When Chandra's image of PSR B1509-58, a spinning neutron star surrounded by a cloud of energetic particles, was released in 2009, it quickly gained attention because many saw a hand-like structure in the X-ray emission. In this new image of the system, X-rays from Chandra in gold are seen along with infrared data from NASA's Wide-field Infrared Survey Explorer (WISE) telescope in red, green, and blue. Pareidolia may strike again in this image as some people report seeing a shape of a face in WISE's infrared data.

RCW 38 (upper right)
A young star cluster about 5,500 light years from Earth, RCW 38 provides astronomers a chance to closely examine many young, rapidly evolving stars at once. In this composite image, X-rays from Chandra are blue, while infrared data from NASA's Spitzer Space Telescope are orange and additional infrared data from the 2MASS survey appears white. There are many massive stars in RCW 38 that will likely explode as supernovas. Astronomers studying RCW 38 are hoping to better understand this environment as our Sun was likely born into a similar stellar nursery.

Hercules A (middle left):
Some galaxies have extremely bright cores, suggesting that they contain a supermassive black hole that is pulling in matter at a prodigious rate. Astronomers call these "active galaxies," and Hercules A is one of them. In visible light (colored red, green and blue, with most objects appearing white), Hercules A looks like a typical elliptical galaxy. In X-ray light, however, Chandra detects a giant cloud of multimillion-degree gas (purple). This gas has been heated by energy generated by the infall of matter into a black hole at the center of Hercules A that is over 1,000 times as massive as the one in the middle of the Milky Way. Radio data (blue) show jets of particles streaming away from the black hole. The jets span a length of almost one million light years.

Kes 73 (middle right):
The supernova remnant Kes 73, located about 28,000 light years away, contains a so-called anomalous X-ray pulsar, or AXP, at its center. Astronomers think that most AXPs are magnetars, which are neutron stars with ultra-high magnetic fields. Surrounding the point-like AXP in the middle, Kes 73 has an expanding shell of debris from the supernova explosion that occurred between about 750 and 2100 years ago, as seen from Earth. The Chandra data (blue) reveal clumpy structures along one side of the remnant, and appear to overlap with infrared data (orange). The X-rays partially fill the shell seen in radio emission (red) by the Very Large Array. Data from the Digitized Sky Survey optical telescope (white) show stars in the field-of-view.

Mrk 573 (lower left):
Markarian 573 is an active galaxy that has two cones of emission streaming away from the supermassive black hole at its center. Several lines of evidence suggest that a torus, or doughnut of cool gas and dust may block some of the radiation produced by matter falling into supermassive black holes, depending on how the torus is oriented toward Earth. Chandra data of Markarian 573 suggest that its torus may not be completely solid, but rather may be clumpy. This composite image shows overlap between X-rays from Chandra (blue), radio emission from the VLA (purple), and optical data from Hubble (gold).

NGC 4736 (lower right):
NGC 4736 (also known as Messier 94) is a spiral galaxy that is unusual because it has two ring structures. This galaxy is classified as containing a "low ionization nuclear emission region," or LINER, in its center, which produces radiation from specific elements such as oxygen and nitrogen. Chandra observations (gold) of NGC 4736, seen in this composite image with infrared data from Spitzer (red) and optical data from Hubble and the Sloan Digital Sky Survey (blue), suggest that the X-ray emission comes from a recent burst of star formation. Part of the evidence comes from the large number of point sources near the center of the galaxy, showing that strong star formation has occurred. In other galaxies, evidence points to supermassive black holes being responsible for LINER properties. Chandra's result on NGC 4736 shows LINERs may represent more than one physical phenomenon.

Image credit: NASA/CXC/SAO

Note: For more information, see Chandra Archive Collection: Chandra's Archives Come to Life.

NGC 1291

This image from NASA's Spitzer Space Telescope, taken in infrared light, shows where the action is taking place in galaxy NGC 1291. The outer ring, colored red in this view, is filled with new stars that are igniting and heating up dust that glows with infrared light. The stars in the central area produce shorter-wavelength infrared light than that seen in the ring, and are colored blue. This central area is where older stars live, having long ago gobbled up the available gas supply, or fuel, for making new stars.

The galaxy is about 12 billion years old and is located in the Eridanus constellation. It is known as a barred galaxy because a central bar of stars (which looks like a blue "S" in this view) dominates its center.

When galaxies are young and gas-rich, stellar bars drive gas toward the center, feeding star formation. Over time, as the star-making fuel runs out, the central regions become quiescent and star-formation activity shifts to the outskirts of a galaxy. There, spiral density waves and resonances induced by the central bar help convert gas to stars. The outer ring, seen here in red, is one such resonance location, where gas has been trapped and ignited into a star-forming frenzy.

Image credit: NASA/JPL-Caltech

Note: For more information, see Galactic Wheel of Life Shines in Infrared.

Sextans A

A small galaxy, called Sextans A, is shown here in a multi-wavelength mosaic captured by the European Space Agency's Herschel mission, in which NASA is a partner, along with NASA's Galaxy Evolution Explorer (GALEX) and the National Radio Astronomy Observatory's Jansky Very Large Array observatory near Socorro, New Mexico. The galaxy is located 4.5 million light-years from Earth in the Sextans constellation.

The environment in this galaxy is similar to that of our infant universe because it lacks in heavy metals, or elements heavier than hydrogen and helium. Heavy metals act in some ways like fertilizers for stars, helping them form and grow. Scientists study galaxies like Sextans A to learn how stars still manage to slowly bloom under these poor-growing conditions. The research provides a better understanding of how the very first stars in our universe came to be.

In this image, the purple shows gas; blue shows young stars and the orange and yellow dots are newly formed stars heating up dust.

Image credit: ESA/NASA/JPL-Caltech/NRAO

Artist's Illustration of a Galactic Protocluster

This artist’s impression depicts the formation of a galaxy cluster in the early Universe. The galaxies are vigorously forming new stars and interacting with each other. Such a scene closely resembles the Spiderweb Galaxy (formally known as MRC 1138-262) and its surroundings, which is one of the best-studied protoclusters.

Illustration credit: ESO/M. Kornmesser

Note: For more information, see Construction Secrets of a Galactic Metropolis.

NGC 6302 - The Butterfly Nebula

Many celestial objects are beautiful – swirling spiral galaxies or glittering clusters of stars are notable examples. But some of the most striking scenes are created during the death throes of intermediate-mass stars, when great clouds of superheated gas are expelled into space. These dying breaths form planetary nebulas like NGC 6302, captured here in this image from the NASA/ESA Hubble Space Telescope.

Known perhaps more appropriately as the Bug or Butterfly Nebula, this complex nebula lies roughly 3800 light-years away from us within the Milky Way. It was formed when a star around five times the mass of our Sun became a red giant, ejected its outer layers, and became intensely hot. Its distinctive shape classifies it as a bipolar nebula, where fast-moving gas can escape more easily from the poles of the dying star than from around its equator. This creates a lobed structure reminiscent of an hourglass or, as in this case, a giant cosmic butterfly.

While this image is beautiful in its own right, the mix of colors actually tells us a lot about physical conditions within the nebula.

The red edges of the butterfly wings represent areas that emit light from the element nitrogen, due to the relatively low temperatures there. Conversely the white splashes closer to the nebula's center pinpoint light emitted by the element sulfur, marking regions of higher temperature and colliding gases closer to the central star.

This hot gas was expelled from the star and collided with slower-moving gas in its path, creating rippling shock waves through the nebula. An example of such a shock wave can be seen in the well-defined white blob towards the top right of the image.

Other colors identify emission from oxygen, helium and hydrogen gases. The observations making up this composite image were taken in optical and ultraviolet light on 27 July 2009, using Hubble's Wide Field Camera 3.

Image credit: NASA/ESA/Hubble SM4 ERO Team

Weather Map for WASP-43b

In this artist's illustration the Jupiter-sized planet WASP-43b orbits its parent star in one of the closest orbits ever measured for an exoplanet of its size – with a year lasting just 19 hours.

The planet is tidally locked, meaning it keeps one hemisphere facing the star, just as the Moon keeps one face toward Earth.

The color scale on the planet represents the temperature across its atmosphere. This is based on data from a recent study that mapped the temperature of WASP-43b in more detail than has been done for any other exoplanet.

Image credit: NASA, ESA, and Z. Levay (STScI)

Note: For more information, see Hubble Reveals Most Detailed Exoplanet Weather Map Ever.

Boulder Cheops

This image of the surface of Comet 67P/Churyumov-Gerasimenko was taken by Rosetta’s OSIRIS narrow-angle camera on 19 September 2014, from a distance of 28.5 km.

The image features a large boulder casting a long shadow on the surface of the comet. The boulder has a maximum dimension of about 45 meters and is the largest structure within a group of boulders located on the lower side of the comet’s larger lobe. This cluster of boulders reminded scientists of the famous pyramids at Giza near Cairo in Egypt, and thus it has been named Cheops for the largest of those pyramids, the Great Pyramid, which was built as a tomb for the pharaoh Cheops (also known as Kheops or Khufu) around 2550 BC.

Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Grooves on Asteroid 21 Lutetia

A portion of asteroid Lutetia, looking into the 55 km-wide Massilia crater (red circular outline) with the North Pole Crater Cluster (NPCC) in the distance (purple outline). The grooves (or ‘lineaments’) are colored according to the crater to which they are associated, i.e. red for Massilia and purple for NPCC. The blue lineaments are associated with the ‘Suspicio’ crater, while the yellow lineaments are not associated with any crater discussed in this study.

Lutetia was imaged in July 2010 by ESA’s Rosetta spacecraft, while en route to Comet 67P/Churyumov-Gerasimenko. Rosetta took images of the 100 km-wide asteroid for about two hours during the flyby. At its closest approach, Rosetta was 3162 km from Lutetia. In the image shown here, north is up.

Image credit: Besse et al (2014); image: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Note: For more information, see Lutetia's Dark Side Hosts Hidden Crater.

Messier 82's Ultraluminous Pulsar

High-energy X-rays streaming from a rare and mighty pulsar (magenta), the brightest found to date, can be seen in this new image combining multi-wavelength data from three telescopes. The bulk of a galaxy called Messier 82 (M82), or the "Cigar galaxy," is seen in visible-light data captured by the National Optical Astronomy Observatory's 2.1-meter telescope at Kitt Peak in Arizona. Starlight is white, and lanes of dust appear brown. Low-energy X-ray data from NASA's Chandra X-ray Observatory are colored blue, and higher-energy X-ray data from NuSTAR are pink.

The magenta object is what's known as an ultraluminous X-ray source, or ULX -- a source of blazing X-rays. Previously, all ULXs were suspected to be massive black holes up to a few hundred times the mass of the sun. But NuSTAR spotted a pulsing of X-rays from this ULX (called M82 X-2) - a telltale sign of a pulsar, not a black hole. A pulsar is a type a neutron star -- a stellar core left over from a supernova explosion -- that sends out rotating beams of high-energy radiation. Scientists were surprised to find the pulsar at the root of the ULX because it shines with a luminosity that is more typical of heftier black holes.

NuSTAR data covers the X-ray energy range of 10 to 40 kiloelectron volts (keV), and Chandra covers the range .1 to 10 keV.

Image credit: NASA/JPL-Caltech/SAO/NOAO

Note: For more information, see:
* M82X-2: Suspected Black Hole Unmasked as Ultraluminous Pulsar
* PIA18840: Galaxy in Different Lights
* PIA18842: Mass Chart for Dead Stars and Black Holes
* PIA18843: NuSTAR Captures the Beat of a Dead Star (Animation)
* PIA18844: Ultraluminous X-ray Sources in M82 Galaxy
* PIA18845: Beacons of X-ray Light (Animation)
* NASA's NuSTAR Telescope Discovers Shockingly Bright Dead Star

Comet 67P/Churyumov-Gerasimenko (30 September 2014)

Four-image montage comprising images taken by Rosetta's navigation camera on 30 September from a distance of 18.1 km from the center of Comet 67P/Churyumov-Gerasimenko. Each of the four frames making up the montage measures about 1.4 kilometers across. The image features Site J, the primary landing site for Rosetta’s lander Philae.

Image credit: ESA/Rosetta/NAVCAM

Comet 67P/Churyumov-Gerasimenko's Dimensions

Comet 67P/Churyumov-Gerasimenko's dimensions, as measured from images taken by Rosetta's OSIRIS imaging system. The images shown in the graphic were taken by Rosetta's navigation camera on 19 August.

The larger lobe of the comet measures 4.1 x 3.2 x 1.3 km, while the smaller lobe is 2.5 x 2.5 x 2.0 km.

More details via the blog: Measuring Comet 67P/C-G

Credits: Image: ESA/Rosetta/NAVCAM; Dimensions: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Gravity Gradients Frame Oceanus Procellarum

Topography of Earth's moon generated from data collected by the Lunar Orbiter Laser Altimeter, aboard NASA's Lunar Reconnaissance Orbiter, with the gravity anomalies bordering the Procellarum region superimposed in blue. The border structures are shown using gravity gradients calculated with data from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission. These gravity anomalies are interpreted as ancient lava-flooded rift zones buried beneath the volcanic plains (or maria) on the nearside of the Moon.

Launched as GRAIL A and GRAIL B in September 2011, the probes, renamed Ebb and Flow, operated in a nearly circular orbit near the poles of the moon at an altitude of about 34 miles (55 kilometers) until their mission ended in December 2012. The distance between the twin probes changed slightly as they flew over areas of greater and lesser gravity caused by visible features, such as mountains and craters, and by masses hidden beneath the lunar surface.

The twin spacecraft flew in a nearly circular orbit until the end of the mission on December 17, 2012, when the probes intentionally were sent into the moon's surface. NASA later named the impact site in honor of late astronaut Sally K. Ride, who was America's first woman in space and a member of the GRAIL mission team.

GRAIL's prime and extended science missions generated the highest-resolution gravity field map of any celestial body. The map will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved.

Image credit: NASA/Colorado School of Mines/MIT/GSFC/Scientific Visualization Studio

Note: For more information, see PIA18821: On the West Coast of the Ocean of Storms (Artist's Concept) and NASA Mission Points to Origin of 'Ocean of Storms' on Earth's Moon.

Comet 67P/Churyumov-Gerasimenko Jets Firing (26 September 2014)

The four images that make up a new montage of comet 67P/Churyumov-Gerasimenko were taken on September 26, 2014 by the European Space Agency's Rosetta spacecraft. At the time, Rosetta was about 16 miles (26 kilometers) from the center of the comet.

In the montage, a region of jet activity can be seen at the neck of the comet. These jets, originating from several discrete locations, are a product of ices sublimating and gases escaping from inside the nucleus.

The overlapping and slightly dissimilar angles of the four images that compose the montage are a result of the combined effect of the comet rotating between the first and last images taken in the sequence (about 10 degrees over 20 minutes), and the spacecraft movement during that same time.

Launched in March 2004, Rosetta was reactivated in January 2014 after a record 957 days in hibernation. Rosetta is composed of an orbiter and lander. Its objectives since arriving at comet 67P/Churyumov-Gerasimenko earlier this month are to study the celestial object up close in unprecedented detail, prepare for landing a probe on the comet's nucleus in November, and after the landing, track the comet's changes through 2015 as it sweeps past the sun.

Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. Rosetta's lander will obtain the first images taken from a comet's surface and will provide comprehensive analysis of the comet's possible primordial composition by drilling into the surface. Rosetta also will be the first spacecraft to witness at close proximity how a comet changes as it is subjected to the increasing intensity of the sun's radiation. Observations will help scientists learn more about the origin and evolution of our solar system and the role comets may have played in seeding Earth with water, and perhaps even life.

Image credit: ESA/Rosetta

Note: For more information, see Rosetta Comet Fires Its Jets.

Comet 67P/Churyumov-Gerasimenko (26 September 2014)

Four-image montage comprising images taken by Rosetta's navigation camera on 26 September from a distance of 26.3 km from Comet 67P/Churyumov-Gerasimenko. The comet nucleus is about 4 km across.

The image shows the spectacular region of activity at the 'neck' of 67P/C-G. This is the product of ices sublimating and gases escaping from inside the comet, carrying streams of dust out into space.

Image credit: ESA/Rosetta/NAVCAM

Titan's South Polar Vortex

These two views of Saturn's moon Titan show the southern polar vortex, a huge, swirling cloud that was first observed by NASA's Cassini spacecraft in 2012.

The view at left is a spectral map of Titan obtained with the Cassini Visual and Infrared Mapping Spectrometer (VIMS) on November 29, 2012. The inset image is a natural-color close-up of the polar vortex taken by Cassini's wide-angle camera (part of the view previously released as PIA14925).

Three distinct components are evident in the VIMS image, represented by different colors: the surface of Titan (orange, near center), atmospheric haze along the limb (light green, at top) and the polar vortex (blue, at lower left).

To the VIMS instrument, the spectrum of the southern polar vortex shows a remarkable difference with respect to other portions of Titan's atmosphere: a signature of frozen hydrogen cyanide molecules (HCN). This discovery has suggested to researchers that the atmosphere of Titan's southern hemisphere is cooling much faster than expected. Observing seasonal shifts like this in the moon's climate is a major goal for Cassini's current extended mission.

Image credit: NASA/JPL-Caltech/ASI/University of Arizona/SSI/Leiden Observatory and SRON

Note: For more information, see Titan's Swirling Polar Cloud is Cold and Toxic (ESA) and Swirling Cloud at Titan's Pole is Cold and Toxic (JPL).

Messier 11 - The Wild Duck Cluster

The Wide Field Imager (WFI) on the MPG/ESO 2.2-meter telescope at the La Silla Observatory in Chile has taken this beautiful image of the open Wild Duck Cluster, Messier 11, or NGC 6705. The blue stars in the center of the image are the young, hot stars of the cluster. The surrounding redder stars are older, cooler background stars.

Image credit: ESO

Note: For more information, see Wild Ducks Take Flight in Open Cluster.