One Revolution of Luhman 16B

ESO's Very Large Telescope has been used to create the first ever map of the weather on the surface of the nearest brown dwarf to Earth. An international team has made a chart of the dark and light features on WISE J104915.57-531906.1B, which is informally known as Luhman 16B and is one of two recently discovered brown dwarfs forming a pair only six light-years from the Sun.

The figure shows the object at sixteen equally-spaced times as it rotates once on its axis.

Illustration credit: ESO/I. Crossfield

Note: For more information, see First Weather Map of Brown Dwarf.

Comet 67P Churyumov-Gerasimenko

This image shows the most recent observations of the 2-mile-wide (4-kilometer-wide) comet 67P/Churyumov-Gerasimenko, which is the upcoming target of the European Space Agency's Rosetta mission. Rosetta is expected to rendezvous with the comet in August 2014.

The image was taken on October 5, 2013, by the Very Large Telescope of the European Southern Observatory in Chile. The comet was around 300 million miles (500 million kilometers) from Earth at the time. (It then passed behind the sun and out of view from Earth's perspective).

Image credit: ESO/Max Planck Institute for Solar System Research

Note: For more information, see PIA17664: U.S. Instruments Aboard Rosetta, PIA17665: Electronics for a Spectrometer, PIA17666: Rosetta at Comet, NASA Instruments on European Comet Spacecraft Begin Countdown, Rosetta: To Chase a Comet, and Rosetta Wide Awake as Check-Up Continues.

Comet C/2013 A1 Siding Spring

NASA's NEOWISE mission captured images of comet C/2013 A1 Siding Spring, which is slated to make a close pass by Mars on October 19, 2014. The infrared pictures reveal a comet that is active and very dusty even though it was about 355 million miles (571 million kilometers) away from the sun on January 16, 2014, when this picture was taken.

The infrared measurements will allow astronomers to determine the sizes and quantity of dust particles being flung off the comet. The measurements will also give engineers some indications of what orbiting spacecraft at Mars might expect when the comet gets close. Preliminary analysis of the data indicate approximately 220 pounds (100 kilograms) of dust are being ejected from the comet's surface each second, assuming the grains are dark and nearly the density of water-ice. The comet's activity is expected to increase as it gets closer to Mars.

Image credit: NASA/JPL-Caltech

Note: For more information, see NASA Preparing for 2014 Comet Watch at Mars.

Messier 51 - The Whirlpool Galaxy

The Whirlpool Galaxy, also known as M51 or NGC 5194, is one of the most spectacular examples of a spiral galaxy. With two spiral arms curling into one another in a billowing swirl, this galaxy hosts over a hundred billion stars and is currently merging with its companion, the smaller galaxy NGC 5195.

Around 30 million light-years away, the Whirlpool Galaxy is close enough to be easily spotted even with binoculars. Using the best telescopes available both on the ground and in space, astronomers can scrutinize its population of stars in extraordinary detail.

In this image, observations performed at three different wavelengths with ESA’s Herschel and XMM-Newton space telescopes are combined to reveal how three generations of stars coexist in the Whirlpool Galaxy.

The infrared light collected by Herschel – shown in red and yellow – reveals the glow of cosmic dust, which is a minor but crucial ingredient in the interstellar material in the galaxy’s spiral arms. This mixture of gas and dust provides the raw material from which the Whirlpool Galaxy’s future generations of stars will take shape.

Observing in visible and ultraviolet light, astronomers can see the current population of stars in the Whirlpool Galaxy, since stars in their prime shine most brightly at shorter wavelengths than infrared. Seen at ultraviolet wavelengths with XMM-Newton and portrayed in green in this composite image are the galaxy’s fiercest stellar inhabitants: young and massive stars pouring powerful winds and radiation into their surroundings.

The image also shows the remains of previous stellar generations, which shine brightly in X-rays and were detected by XMM-Newton. Shown in blue, these sources of X-rays are either the sites where massive stars exploded as supernovae in the past several thousand years, or binary systems that host neutron stars or black holes, the compact objects left behind by supernovae.

Image credit: ESA / Herschel / XMM-Newton. Acknowledgements: "Physical Processes in the Interstellar Medium of Very Nearby Galaxies" Key Programme, Christine Wilson

Asteroid 2415 Ganesa and Star Cluster NGC 2158

More than 100 asteroids were captured in this view from NASA's Wide-field Infrared Survey Explorer, or WISE, during its primary all-sky survey. In August of this year, the mission was revived to hunt more asteroids, and renamed NEOWISE.

Not all of the asteroids are easy to see, but some stand out as a series of dots. Each dot in a track shows one asteroid, captured at different times as it marched across the sky. The asteroid at center left is called (2415) Ganesa.

Clusters of stars can also be seen; for example, NGC 2158 glitters like a jeweled brooch at center right. There are about 2,500 stars in this view, which is about 30 light-years across.

Clouds of gas and dust surround the region, visible only in infrared light.

These data were acquired in March 2010, before WISE was put into hibernation in 2011.

Image credit: NASA/JPL-Caltech/UCLA

Note: For more information, see NEOWISE Celebrates First Month of Operations After Reactivation.

Opportunity's January 2014 Self-Portrait

NASA's Mars Exploration Rover Opportunity recorded the component images for this self-portrait about three weeks before completing a decade of work on Mars. The rover's panoramic camera (Pancam) took the images during the interval January 3, 2014, to January 6, 2014, a few days after winds removed some of the dust that had been accumulating on the rover's solar panels.

Opportunity landed on Mars on January 25, 2004, Universal Time (January 24, 2004, PST) for a mission that was planned to last three months. It is still active 10 Earth years later.

This image is presented as a vertical projection. The mast on which the Pancam is mounted does not appear in the image, though its shadow does.

Image credit: NASA/JPL-Caltech/Cornell University/Arizona State University

Note: For more information, see PIA17758: Opportunity's First Decade of Driving on Mars and NASA's Opportunity at 10: New Findings from Old Rover.

Black Hole Amid Galaxy Cluster RX J1532.9+3021

RX J1532.9+3021: The black hole is in a galaxy cluster located about 3.9 billion light years from Earth.

Astronomers have used NASA's Chandra X-ray Observatory and other telescopes to reveal one of the most powerful black holes known. The supermassive black hole is in the center of a galaxy cluster named RX J1532.9+3021 located about 3.9 billion light years from Earth. The image here is a composite of X-ray data from Chandra revealing hot gas in the cluster in purple and optical data from the Hubble Space Telescope showing galaxies in yellow. Supersonic jets generated by the black hole have drilled into the hot gas and pushed it aside, forming the large cavities that can be seen on either side of the central galaxy (mouse over the image for a labeled version).

Scale: Image is 1.6 arcmin on a side (about 1.6 million light years).

Image credit: X-ray: NASA/CXC/Stanford/J.Hlavacek-Larrondo et al, Optical: NASA/ESA/STScI/M.Postman & CLASH team

Note: For more information, see RX J1532.9+3021: Extreme Power of Black Hole Revealed.

Water Vapor Around Ceres

Dwarf planet Ceres is located in the main asteroid belt, between the orbits of Mars and Jupiter, as illustrated in this artist's conception. Observations by the Herschel space observatory between 2011 and 2013 find that the dwarf planet has a thin water vapor atmosphere. This is the first unambiguous detection of water vapor around an object in the asteroid belt.

Illustration credit: ESA/ATG medialab

Note: For more information, see PIA17831: Water Detection on Ceres, Herschel Telescope Detects Water on Dwarf Planet, Herschel Discovers Water Vapor Around Dwarf Planet Ceres, and Water Detected on Dwarf Planet Ceres.

Messier 8 - The Lagoon Nebula

The VLT Survey Telescope (VST) at ESO's Paranal Observatory in Chile has captured this richly detailed new image of the Lagoon Nebula. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of eleven public surveys of the sky now in progress using ESO telescopes. Together these are providing a vast legacy of publicly available data for the global astronomical community.

Photo credit: ESO/VPHAS+ team

Note: For more information, see Sneak Preview of Survey Telescope Treasure Trove.

Countdown to Pluto

Are we there yet?

One of the fastest spacecraft ever built -- NASA's New Horizons -- is hurtling through the void at nearly one million miles per day. Launched in 2006, it has been in flight longer than some missions last, and it is nearing its destination: Pluto.

“The encounter begins next January,” says Alan Stern, of the Southwest Research Institute and the mission’s principal investigator. “We’re less than a year away.”

Closest approach is scheduled for July 2015 when New Horizons flies only 10,000 km from Pluto, but the spacecraft will be busy long before that date. The first step, in January 2015, is an intensive campaign of photography by the Long Range Reconnaissance Imager or “LORRI.” This will help mission controllers pinpoint Pluto's location, which is uncertain by a few thousand kilometers.

"LORRI will photograph the planet against known background star fields," explains Stern. "We’ll use the images to refine Pluto’s distance from the spacecraft, and then fire the engines to make any necessary corrections.”

At first, Pluto and its large moon Charon will be little more than distant pinpricks—“a couple of fat pixels,” says Stern--but soon they will swell into full-fledged worlds.

By late April 2015, the approaching spacecraft will be taking pictures of Pluto that surpass the best images from Hubble. By closest approach in July 2015, a whole new world will open up to the spacecraft’s cameras. If New Horizons flew over Earth at the same altitude, it could see individual buildings and their shapes.

Stern is looking forward to one of the most exciting moments of the Space Age.

“Humankind hasn't had an experience like this--an encounter with a new planet--in a long time,” he says. “Everything we see on Pluto will be a revelation.”

He likens New Horizons to Mariner 4, which flew past Mars in July 1965. At the time, many people on Earth, even some scientists, thought the Red Planet was a relatively gentle world, with water and vegetation friendly to life. Instead, Mariner 4 revealed a desiccated wasteland of haunting beauty. New Horizons’ flyby of Pluto will occur almost exactly 50 years after Mariner 4’s flyby of Mars—and it could shock observers just as much.

Other than a few indistinct markings seen from afar by Hubble, Pluto’s landscape is totally unexplored. Although some astronomers call Pluto a “dwarf” planet, Stern says there’s nothing small about it. “If you drove a car around the equator of Pluto, the odometer would rack up almost 5,000 miles—as far as from Manhattan to Moscow.” Such a traveler might encounter icy geysers, craters, clouds, mountain ranges, rilles and valleys, alongside alien landforms no one has ever imagined.

“There is a real possibility that New Horizons will discover new moons and rings as well,” says Stern.

Yes, Pluto could have rings. Already, Pluto has five known moons: Charon, Styx, Nix, Kerberos, and Hydra. Numerical simulations show that meteoroids striking those satellites could send debris into orbit, forming a ring system that waxes and wanes over time in response to changes in bombardment.

“We’re flying into the unknown,” says Stern, “and there is no telling what we might find.”

Video credit: NASA

Lunar Crustal Thickness Map

Global map of crustal thickness of the moon derived from gravity data obtained by NASA's GRAIL spacecraft. The lunar near side is represented on the left hemisphere. The far side is represented in the right hemisphere.

In the left hemisphere, outlined in white, is the Procellarum KREEP Terrane, a large province on the near side of the moon which contains high abundances of potassium, rare earth elements and phosphorus. Excluding the Aitken basin at the south pole (the gray circle on the lower half of the far side hemisphere), there are 12 impact basins with crustal thinning that have diameters greater than 124 miles (200 kilometers) on each hemisphere. Those are marked with black circles. The image is presented in two hemispherical Lambert azimuthal equal-area projections centered over the near side (left), and far side (right) hemispheres.

Map credit: NASA/JPL-Caltech/S. Miljkovic

Note: For more information, see NASA's GRAIL Mission Puts a New Face on the Moon.

Kasei Valles - The Floodwaters of Mars

Ten years ago, on 14 January 2004, Mars Express took its very first images of Mars in color and in 3D.

To mark the occasion, the team produced a fly-through movie of the ancient flood plain Kasei Valles. The movie is based on the 67-image mosaic released as part of the ten-years-since-launch celebrations in June 2013.

The scene spans 987 km in the north–south direction, 19–36°N, and 1550 km in the east–west direction (280–310°E). It covers 1.55 million square kilometers, an area equivalent to the size of Mongolia.

Kasei Valles is one of the largest outflow channel systems on Mars, created during dramatic flood events. From source to sink, it extends some 3000 km and descends 3 km.

Kasei Valles splits into two main branches that hug a broad island of fractured terrain – Sacra Mensa – rising 2 km above the channels that swerve around it. While weaker materials succumbed to the erosive power of the fast-flowing water, this hardier outcrop has stood the test of time.

Slightly further downstream, the flood waters did their best to erase the 100 km-wide Sharonov crater, crumpling its walls to the south. Around Sharonov many small streamlined islands form teardrop shapes rising from the riverbed as water swept around these natural obstacles.

Video credit: ESA/DLR/FU Berlin (G. Neukum)

Stormy Weather on Brown Dwarf Stars

This artist's concept shows what the weather might look like on cool star-like bodies known as brown dwarfs. These giant balls of gas start out life like stars, but lack the mass to sustain nuclear fusion at their cores, and instead, fade and cool with time.

New research from NASA's Spitzer Space Telescope suggests that most brown dwarfs are racked with colossal storms akin to Jupiter's famous "Great Red Spot." These storms may be marked by fierce winds, and possibly lightning. The turbulent clouds might also rain down molten iron, hot sand or salts -- materials thought to make up the cloud layers of brown dwarfs.

Image credit: NASA/JPL-Caltech/University of Western Ontario/Stony Brook University

Note: For more information, see Stormy Stars? NASA's Spitzer Probes Weather on Brown Dwarfs.

Three Exoplanets Orbiting a Solar Twin in Messier 67

This artist's impression shows one of the three newly discovered planets in the star cluster Messier 67. In this cluster the stars are all about the same age and composition as the Sun. This makes it a perfect laboratory to study how many planets form in such a crowded environment. Very few planets in clusters are known and this one has the additional distinction of orbiting a solar twin — a star that is almost identical to the Sun in all respects.

Illustration credit: ESO/L. Calçada

Note: For more information, see First Planet Found Around Solar Twin in Star Cluster.

Asteroid 2013 YP139

The six red dots in this composite picture indicate the location of the first new near-Earth asteroid seen by NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) since the spacecraft came out of hibernation in December 2013. The asteroid, called 2013 YP139, is the first of hundreds of space-rock discoveries expected during its renewed mission. The inset shows a zoomed-in view of one of the detections of 2013 YP139.

2013 YP139 was discovered by NEOWISE on December 29, 2013. The mission's sophisticated software picked out the moving object against a background of stationary stars.

Near-Earth objects are asteroids and comets with orbits that come close to Earth's path around the sun. 2013 YP139, is currently about 27 million miles (43 million kilometers) from Earth. Based on its infrared brightness, scientists estimate it to be approximately 0.4 miles (650 meters) in diameter and extremely dark. Because NEOWISE is an infrared telescope, it senses heat from asteroids. 2013 YP139 is as dark as a piece of coal, and it glows brightly at infrared wavelengths. The shortest infrared wavelength, 3.4 microns, is color-coded blue, and the longer wavelength, 4.6 microns, is color-coded red. The asteroid appears as a string of red dots because it is much cooler than the stars. Stars are thousands of degrees, but the asteroid is close to room temperature, so it is red in these images.

While asteroid 2013 YP139 orbits the sun in an elliptical orbit nearly in the plane of our solar system and is classified as a potentially hazardous asteroid, it is not likely to approach within Earth's vicinity anytime over the next 100 years. However, the asteroid's future motion can bring it within about 300,000 miles (490,000 kilometers) of Earth's orbit, so its long-term motion will be closely monitored.

The image is about 1.5 degrees across. Asteroid 2013 YP139 was traveling across the sky at about 3.2 degrees per day when these images were taken. For reference, the full moon is about 0.5 degree across.

Image credit: NASA/JPL-Caltech

Note: For more information, see Recently Reactivated NASA Spacecraft Spots Its First New Asteroid.

GOODS North

This is a portion of a deep-sky Hubble Space Telescope survey called GOODS North (Great Observatories Origins Deep Survey). The view is a composite of images taken in visible and near-infrared light by NASA's Hubble Space Telescope. Researchers have circled four unusually red objects (see poster version) that appear as they existed just 500 million years after the big bang. They appear red because their light has been stretched to longer infrared wavelengths by the expansion of the universe. These extremely compact and bright galaxies present a puzzle to researchers because they are much more luminous than anything previously seen at such an early epoch. The young galaxies are bright because they are forming stars at a much faster rate than for other galaxies found at such early times.

Using NASA's Spitzer Space Telescope, the astronomers were able to estimate the stellar masses by measuring the total stellar luminosity of the galaxies.

Image credit: NASA/ESA/UCSC/Leiden University

Pulsar Wind Nebula PSR B1509-58

Can you see the shape of a hand in this new X-ray image? The hand might look like an X-ray from the doctor's office, but it is actually a cloud of material ejected from a star that exploded. NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, has imaged the structure in high-energy X-rays for the first time, shown in blue. Lower-energy X-ray light previously detected by NASA's Chandra X-ray Observatory is shown in green and red.

Nicknamed the "Hand of God," this object is called a pulsar wind nebula. It's powered by the leftover, dense core of a star that blew up in a supernova explosion. The stellar corpse, called PSR B1509-58, or B1509 for short, is a pulsar: it rapidly spins around, seven times per second, firing out a particle wind into the material around it -- material that was ejected in the star's explosion. These particles are interacting with magnetic fields around the material, causing it to glow with X-rays. The result is a cloud that, in previous images, looked like an open hand. The pulsar itself can't be seen in this picture, but is located near the bright white spot.

One of the big mysteries of this object is whether the pulsar particles are interacting with the material in a specific way to make it look like a hand, or if the material is in fact shaped like a hand.

NuSTAR's view is providing new clues to the puzzle. The hand actually shrinks in the NuSTAR image, looking more like a fist, as indicated by the blue color. The northern region, where the fingers are located, shrinks more than the southern part, where a jet lies, implying the two areas are physically different.

The red cloud at the end of the finger region is a different structure, called RCW 89. Astronomers think the pulsar's wind is heating the cloud, causing it to glow with lower-energy X-ray light.

In this image, X-ray light seen by Chandra with energy ranges of 0.5 to 2 kiloelectron volts (keV) and 2 to 4 keV is shown in red and green, respectively, while X-ray light detected by NuSTAR in the higher-energy range of 7 to 25 keV is blue.

Image credit: NASA/JPL-Caltech/McGill

Note: For more information, see PIA17567: Different Flavors of Black Holes and Dead Star and Distant Black Holes Dazzle in X-Rays.

Hubble Frontier Field Abell 2744

This long-exposure image from NASA's Hubble Space Telescope of massive galaxy cluster Abell 2744 is the deepest ever made of any cluster of galaxies. It shows some of the faintest and youngest galaxies ever detected in space. Abell 2744, located in the constellation Sculptor, appears in the foreground of this image. It contains several hundred galaxies as they looked 3.5 billion years ago. The immense gravity in Abell 2744 acts as a gravitational lens to warp space and brighten and magnify images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did longer than 12 billion years ago, not long after the big bang.

This image is part of an unprecedented long-distance view of the universe from an ambitious collaborative project among NASA's Hubble, Spitzer and Chandra space telescopes called The Frontier Fields. Over the next several years, select patches of the sky will be photographed for the purpose of better understanding galaxy evolution. This visible-light and near-infrared composite image was taken with Hubble's Wide Field Camera 3.

Image credit: NASA/ESA/STScI

Note: For more information, see Pandora's Magnifying Glass - First Image from Hubble's Frontier Fields and NASA's Hubble and Spitzer Team up to Probe Faraway Galaxies.

Tarantula Nebula

This new Hubble image shows a cosmic creepy-crawly known as the Tarantula Nebula in infrared light. This region is full of star clusters, glowing gas, and thick dark dust.

Created using observations taken as part of the Hubble Tarantula Treasury Project (HTTP), this image was snapped using Hubble's Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS). The Hubble Tarantula Treasury Project (HTTP) is scanning and imaging many of the many millions of stars within the Tarantula, mapping out the locations and properties of the nebula's stellar inhabitants. These observations will help astronomers to piece together an understanding of the nebula's skeleton, viewing its starry structure.

Image credit: NASA, ESA, E. Sabbi (STScI)

Note: For more information, see Unravelling the Web of a Cosmic Creepy-Crawly.

Messier 83

This new Hubble image shows the scatterings of bright stars and thick dust that make up spiral galaxy Messier 83, otherwise known as the Southern Pinwheel Galaxy. One of the largest and closest barred spirals to us, this galaxy is dramatic and mysterious; it has hosted a large number of supernova explosions, and appears to have a double nucleus lurking at its core.

Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA). Acknowledgement: William Blair (Johns Hopkins University)

Note: For more information, see A Galaxy With Two Hearts.

Black Hole Flare in Abell 1795

Abell 1795: A bright flare seen with Chandra provides evidence for a black hole having torn a star apart.

A bright, long duration flare may be the first recorded event of a black hole destroying a star in a dwarf galaxy. The dwarf galaxy is located in the galaxy cluster Abell 1795, about 800 million light years from Earth. A composite image of the cluster shows Chandra data in blue and optical data from the Canada-France-Hawaii Telescope in red, green and blue. An inset centered on the dwarf galaxy shows Chandra data taken between before and after 2005. The X-ray flare provides evidence that a large black hole has pulled in debris from a star that was torn apart by tidal forces.

Scale: Image is 6.8 arcmin on a side (about 1.5 million light years).

Image credit: X-ray: NASA/CXC/Univ. of Alabama/W.P.Maksym et al & NASA/CXC/GSFC/UMD/D.Donato, etal; Optical: CFHT

Note: For more information, see Abell 1795: Death By Black Hole In Small Galaxy?

Beta Pictoris b

This image taken by the Gemini Planet Imager (GPI) shows a planet orbiting the star Beta Pictoris. In addition to the image, the GPI obtains spectral information from every pixel element in the field of view, allowing scientists to study the planet in great detail.

Beta Pictoris b is a giant planet -- several times larger than Jupiter -- and is approximately ten million years old. This near-infrared image show the planet glowing in infrared light from the heat released in its formation. The bright star Beta Pictoris is hidden behind a mask in the center of the image; a few scattered starlight artifacts, called speckles, are also visible but vastly fewer than in previous images.

Image credit: Gemini/Christian Marois, NRC Canada

Note: For more information, see Powerful Planet Finder Turns Its Eye to the Sky.

Supernova 1987A

This image shows the remnant of Supernova 1987A seen in light of very different wavelengths. ALMA data (in red) shows newly formed dust in the center of the remnant. Hubble (in green) and Chandra (in blue) data show where the expanding shock wave is colliding with a ring of material around the supernova. This ring was initially lit up by the ultraviolet flash from the original explosion, but over the past few years the ring material has brightened considerably as it collides with the expanding shockwave.

Image credit: ALMA (ESO/NAOJ/NRAO)/A. Angelich. Visible light image: the NASA/ESA Hubble Space Telescope. X-Ray image: The NASA Chandra X-Ray Observatory

Note: For more information, see ALMA Spots Supernova Dust Factory.

Asteroid 2014 AA

Several sources confirm that the first discovered asteroid in 2014, designated 2014 AA, entered Earth's atmosphere late January 1 (January 2 Universal time) over the mid-Atlantic Ocean. The Catalina Sky Survey operating near Tucson, Arizona discovered this very small asteroid -- 6 to 9 feet (2 to 3 meters) in size -- early on the morning of January 1, and immediately followed up on it. (An animation of the discovery images is shown [above]). The asteroid entered Earth's atmosphere about 21 hours later, and probably broke up.

The high-precision astrometry data and rapid follow-up observations provided by the Catalina Sky Survey team made it possible for orbit analysts from NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California, to determine possible Earth impact locations. Before that, and based upon the Catalina Sky Survey observations, Steve Chesley of JPL produced a plot of the possible impact locations for asteroid 2014 AA. (Chesley's graphic is shown in Figure 2, where the blue, nearly horizontal band represents the region of possible impacts).

The geolocation derived by Chesley allowed Peter Brown of the University of Western Ontario, and Petrus Jenniskens of the SETI Institute, Mountain View, California, to search the data from low-frequency infrasound observation sites of the Comprehensive Nuclear-Test-Ban Treaty Organization. They found weak signals from stations in Bolivia, Brazil and Bermuda that indicated that the likely impact location was indeed positioned within the predicted area. The location, marked with a red dot, is still somewhat uncertain due to observational factors, including atmospheric effects on the propagation of infrasound signals.

Infrasound stations record ultra-low-frequency sound waves to monitor the location of atmospheric explosions. These sites often pick up airbursts from small asteroid impacts, commonly called fireballs or bolides. There are about a billion near-Earth objects in the size range of 2014 AA, and impacts of comparably sized objects occur several times each year.

Uncertainties present in the infrasound technique and the very limited amount of optical tracking data before impact make it difficult to pinpoint the impact time and location. Even so, Chesley provides the following estimate:

Impact time: January 1, 2014 at 11:02 p.m. EST (January 2 4:02 UTC) Impact location coordinates: 11.7 degrees north latitude, 319.7 degrees latitude.

This information is preliminary and has uncertainties of perhaps a few hundred kilometers, or miles, in location, and tens of minutes in time.

Prior to impact, the orbit of 2014 AA had a very low inclination (about 1 degree) with respect to the ecliptic plane and an orbit that ranged from 0.9 to 1.3 astronomical units from the sun, with an orbital period of about 1.2 years.

Image credit: CSS/LPL/UA

Note: For more information, see First 2014 Asteroid Discovered: Update.