ESA Rosetta: Fissure spanning 100 metres discovered on Comet 67/P

A fissure spanning over 100 meters across the neck of Rosetta’s comet 67P raises the question of if, or when, the comet will break up. 

The fissure is part of released studies by Rosetta scientists in the journal Science. 

Credit: ESA/Rosetta, Illustration, T.Reyes

Not all comets break up as they vent and age, but for ESA Rosetta's comet 67P, the Rubber Duckie comet, a crack in the neck raises concerns.

Some comets may just fizzle and uniformly expel their volatiles throughout their surfaces. They may become like puffballs, shrink some but remain intact.

Comet 67P is the other extreme. The expulsion of volatile material has led to a shape and a point of no return; it is destined to break in two.

The fissure is part of the analysis in a new set of science papers published this week.

The images show a fissure spanning a few hundred meters across the neck of the two lobe comet.

The fissure is just one of the many incredible features on Comet 67P and is reported in research articles released in the January 22, 2015, edition of the journal Science.

Left: A map looking at the northern (right-hand rule, positive,) pole of 67P showing the total energy received from the Sun per rotation on 6 August 2014. 

The base of the neck (Hapi) receives ~15% less energy than the most illuminated region, 3.5 × 106 J m-2 (per rotation). 

If self-heating were not included, the base of the neck would receive ~30% less total energy. 

Right: Similar to the left panel but showing total energy received over an entire orbital period in J m-2 (per orbit). 

Credit:ESA

What it means is not certain, but Rosetta team scientists have stated that flexing of the comet might be causing the fissure.

As the comet approaches the Sun, the solar radiation is raising the temperature of the surface material.

Like all materials, the comet's will expand and contract with temperature. And diurnal (daily) changes in the tidal forces from the Sun is a factor, too.'

The crack, or fissure, could spell the beginning of the end for comet 67P/Churyumov–Gerasimenko. It is located in the neck area, in the region named Hapi, between the two lobes that make 67P appear so much like a Rubber Duck from a distance.

The fissure could represent a focal point of many properties and forces at work, such as the rotation rate and axis – basically head over heels of the comet.

The fissure lies in the most active area at present, and possibly the most active area overall.

Though the Hapi region appears to receive nearly constant sunlight, at this time, Rosetta measurements (below) show otherwise – receiving 15% less sunlight than elsewhere.

Top left: The Hathor cliff face is to the right in this view. The aligned linear structures can be clearly seen. 

The smooth Hapi region is seen at the base of the Hathor cliff. Boulders are prevalent along the long axis of the Hapi region. 

Bottom left and right: Crack in the Hapi region. 

The left panel shows the crack (indicated by red arrows) extending across Hapi and beyond. 

The right panel shows the crack where it has left Hapi and is extending into Anuket, with Seth at the uppermost left and Hapi in the lower left. 

Credit: ESA/Rosetta

Sunlight and heating are major factors and the neck likely experiences the greatest mechanical stresses, internal torques, from heating or tidal forces from the sun as it rotates and approaches perihelion.

Rosetta scientists are still not certain whether 67P is two bodies in contact, a contact binary, or a shape that formed from material expelled about the neck area leading to its narrowing.

The Philae lander's MUPUS thermal sensor measured a temperature of –153°C (–243°F) at the landing site, while VIRTIS, an instrument on the primary spacecraft Rosetta, has measured -70°C (-94°F) at present.

These temperatures will rise as perihelion is reached on August 13, 2015, at a distance of 1.2432 A.U. (24% further from the Sun than Earth). At present – January 23rd – 67P is 2.486 A.U. from the Sun (2 1/2 times farther from the Sun than Earth).

While not a close approach to the Sun for a comet, the Solar radiation intensity will increase by 4 times between the present (January 2014) and perihelion in August.

Stresses due to temperature changes from diurnal variations, the changing Sun angle during perihelion approach, from loss of material, and finally from changes in the tidal forces on a daily basis (12.4043 hours) may lead to changes in the fissure causing it to possibly widen or increase in length.

Rosetta will continue escorting the comet and delivering images of the whole surface that will give Rosetta scientists the observations and measurements to determine 67P/Churyumov–Gerasimenko's condition now and its fate in the longer term.

Read the full article here

UK Space Agency Announce discovery of Beagle-2 on Mars

Following a lengthy and protracted briefing by the UK Space Agency, they finally acknowledged the discovery of the Beagle 2 on Mars by the HiRise camera on MRO.

The UK Agency seemed to feel the need to promote their apparent expertise and kudos before breaking the news before showing off the grainy images.

This is one of the images shown at the briefing. It is far from clear but we are assured it contains the component parts of the UK's failed Beagle 2.

More than 11 years after UK Mars probe Beagle 2 was lost, believed crashed, space scientists are set to reveal new findings about what hapened to the spacecraft.

Mystery surrounds exactly what will be disclosed by experts from the European Space Agency and the underfunded, struggling, UK Space Agency at the English National Academy of Science, known as the Royal Society in London on Friday, but it has raised hopes that orbiting spacecraft around Mars might have located the debris of the Beagle 2.

The probe was the brainchild of the eccentric, mutton-chopped Professor Colin Pillinger, of the UK’s Open University, who died suddenly in May 2014 from a brain haemorrhage.

Beagle 2 was carried to Mars by ESA’s Mars Express which remains in orbit to this day performing valuable surveys of the planet.

Beagle was due to land on Christmas Day 2003, but nothing was ever heard from the tiny craft.

Experts later concluded that its parachute had failed in the extra thin atmosphere and it hit the ground too hard.

Months later, Colin called an impromptu press conference, convinced that he had identified a speck in a photo of the martian surface as his lost probe, but later higher-resolution imagery from a NASA orbiter showed there was nothing.

This recent announcement would indicate that this time there is hope that something really has been spotted.

The panel at Friday’s announcement will include Beagle 2’s mission manager Professor Mark Sims, Dr John Bridges of Leicester University’s Space Research Centre, the European Space Agency’s director of science and robotic exploration Alvaro Giménez, and David Parker, of Durham University and the underfunded UK Space Agency.

A recent image from the HiRise camera on the NASA MRO. 

Credit: NASA, JPL, University of Arizona

All are remaining tight-lipped about what will be revealed, but interestingly, Dr Bridges is a member of the team working with the HiRISE camera aboard NASA's Mars Reconnaissance Orbiter, which is the only imager powerful enough to pick out the debris of Beagle 2, or any other probe, from orbit.

John Zarnecki, Emeritus Professor of Space Science, and Professor Pillinger’s former colleague, told reporters: “I don’t know what they will announce. All one can think of is that they might have got an image of the probe, but if Beagle 2 is in a thousand pieces, it is unlikely that we will have found the pieces.”

“When dear old Colin was alive, he imagined he could see the Beagle 2 in single pixels. None of us could see it, he was the only one who could. So if they really have found it this time, it would be wonderful.”

Professor Zarnecki, who headed the OU’s Planetary and Space Sciences department, said that finding Beagle 2 would be an important event, but there was no chance that it could still work.

He said: “The probe will be dead. There could be no battery life and it would have frozen probably. Electronic materials and components don’t like the cold of Mars very much.”

“The main thing is that it could tell us something about how and why it failed. We’re not going to get anything scientific out of it now, but anything we can learn about how and why it failed informs our designs for the future.

“One of the reasons why space missions on the whole are so successful is that we do learn from experience. It is similar to why flying by plane is so safe - we learn from failures.”

Professor Zarnecki had his own experiment on Beagle 2, a tiny device to measure temperature, air pressure, and wind-speed and direction, “like a weather station, but a fancy one”, he said.

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ESA Rosetta Mission: ROSINA water vapour discovery

ESA announced the latest important discovery regarding comet 67P/Churyumov–Gerasimenko.

Rosetta spacecraft orbiting the comet has found the water vapour from its target to be significantly different to that found on Earth.

The discovery made by Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) fuels the debate on the origin of our planet's oceans.

That's not all, ESA's Rosetta project scientist, Matt Taylor, believes that ROSINA will make more key findings for our understanding of the origin of life. "ROSINA is continuing to take measurements and will for the rest of the mission," Taylor told reporters.

"It is making and will make invaluable detections of the composition of the comets atmosphere, as well as monitoring its density."

ROSINA is a combination of two mass spectrometers and a pressure sensor. The mass spectrometers determine the composition of the comet's atmosphere and ionosphere, measure the temperature and bulk velocity of the gas and ions, and investigate reactions in which they take part.

The ROSINA pressure sensor is capable of measuring both total and ram pressure, and will be used to determine the gas density and rate of radial gas flow.

"It can detect many different kinds of molecules and get to the heart of the constituents of the ancient comet, giving us unprecedented insight into what the conditions were at the beginning of the solar system," Taylor revealed.

Add caption

No single instrument could have the capabilities required to accomplish the ROSINA science objectives, so a three-sensor approach has been adopted.

Each sensor is optimized for a part of the scientific objectives, while at the same time complementing the other sensors.

The latest results were the most anticipated, because the origin of Earth's water is still an open question.

Taylor noticed that those findings have put recent Herschel results into context and agree with results from the Giotto mission.

"It is a very important result and was of the most anticipated, if only that it was one of the first we would be able to make," he said.

In January 2014, ESA's Herschel mission discovered water vapor around dwarf planet Ceres, and in 1986, ESA's Giotto was the first spacecraft to make close up observations of a comet.

Comets in particular are unique tools for probing the early Solar System. They harbor material left over from the protoplanetary disc out of which the planets formed, and therefore should reflect the primordial composition of their places of origin.

Asteroid 62412: Tail discovered on long-known asteroid

The faint tail can be seen in active asteroid 62412. 

Credit: Scott Sheppard

A two-person team of Carnegie's Scott Sheppard and Chadwick Trujillo of the Gemini Observatory has discovered a new active asteroid, called 62412, in the Solar System's main asteroid belt between Mars and Jupiter.

It is the first comet-like object seen in the Hygiea family of asteroids. Sheppard will present his team's findings at the American Astronomical Society's Division of Planetary Sciences meeting and participate on Tuesday, November 11, in a press conference organized by the society.

Active asteroids are a newly recognized phenomenon. 62412 is only the 13th known active asteroid in the main asteroid belt. Sheppard and Trujillo estimate that there are likely about 100 of them in the main asteroid belt, based on their discovery.

Active asteroids have stable orbits between Mars and Jupiter like other asteroids. However, unlike other asteroids, they sometimes have the appearance of comets, when dust or gas is ejected from their surfaces to create a sporadic tail effect.

Sheppard and Trujillo discovered an unexpected tail on 62412, an object which had been known as a typical asteroid for over a decade.

Their findings reclassify it as an active asteroid. The reasons for this loss of material and subsequent tail in active asteroids are unknown, although there are several theories such as recent impacts or sublimation from solid to gas of exposed ices.

"Until about ten years ago, it was pretty obvious what a comet was and what a comet wasn't, but that is all changing as we realize that not all of these objects show activity all of the time," Sheppard said.

In the past, asteroids were thought to be mostly unchanging objects, but an improved ability to observe them has allowed scientists to discover tails and comas, which are the thin envelope of an atmosphere that surrounds a comet's nucleus.

"We're actually looking anew through our deep survey at a population of objects that other people cannot easily observe, because we're going much deeper," Sheppard said, explaining why they were able to see that 62412 was active when it had been considered a typical main belt asteroid for 15 years.

Discoveries such as this one can help researchers determine the processes that cause some asteroids to become active.

Sheppard will discuss his and Trujillo's theories about the genesis of 62412's activity. They found that 62412 has a very fast rotation that likely shifts material around its surface, some of which may be emitted to form the comet-like appearance.

The tail may be created directly from ejected material off the fast rotating nucleus, or from ice within the asteroid subliming into water vapor after being freshly exposed on the surface.

They also find a density for 62412 typical of primitive asteroids and not consistent with the much lower-density comets. Further monitoring of this unusual object will help confirm the activity's source.

Sheppard and Trujillo have a paper about this work in press at The Astronomical Journal.

ESA's GAIA satellite set to discover thousands of planets in Milky Way

Princeton University and Lund University researchers project that the recently launched ESA's Gaia satellite could discover tens of thousands of planets during its five-year mission. 

In this image, the colored portions indicate the number of observations Gaia would make of a particular part of the sky during its mission; the scale at the bottom indicates the number of observations from zero (purple) to 200 (red). 

The total number of observations of any part of the sky ranges from about 60 at low ecliptic latitudes to about 80 at high ecliptic latitudes, with a maximum of about 150-200 at intermediate latitudes. 

From these many different observations of each star, the highly accurate Gaia measurements will reveal the tiny star motion, or "wobble," that results from any orbiting planet. 

Credit: Lennart Lindegren, Lund University

A recently launched European satellite could reveal tens of thousands of new planets within the next few years, and provide scientists with a far better understanding of the number, variety and distribution of planets in our galaxy, according to research published today.

Researchers from Princeton University and Lund University in Sweden calculated that ESA's observational satellite Gaia could detect as many as 21,000 exoplanets, or planets outside of Earth's solar system, during its five-year mission.

If extended to 10 years, Gaia could detect as many as 70,000 exoplanets, the researchers report.

The researchers' assessment is accepted in the Astrophysical Journal and was published Nov. 6 in advance-of-print on arXiv, a preprint database run by Cornell University.

Exoplanets will be an important "by-product" of Gaia's mission, Perryman said. Built and operated by the European Space Agency (ESA) and launched in December 2013, Gaia will capture the motion, physical characteristics and distance from Earth, and one another, of roughly 1 billion objects, mostly stars, in the Milky Way galaxy with unprecedented precision.

The presence of an exoplanet will be determined by how its star "wobbles" as a result of the planet's orbit around it.

More important than the numbers of predicted discoveries are the kinds of planets that the researchers expect Gaia to detect, many of which, such as planets with multi-year orbits that pass directly, or transit, in front of their star as seen from Earth, are currently difficult to find, explained first author Michael Perryman, an adviser on large scientific programs who made the assessment while serving as Princeton's Bohdan Paczyński Visiting Fellow in the Department of Astrophysical Sciences, Dublin.

The satellite's instruments could reveal objects that are considered rare in the Milky Way, such as an estimated 25 to 50 Jupiter-sized planets that orbit faint, low-mass stars known as red dwarfs.

One of the main objectives of the Gaia mission is to establish the currently uncertain distance from Earth to various stars using high-precision triangulation, which would allow a much better understanding of the properties of the stars and the planets orbiting them. 

Of the 1,163 confirmed transiting planets, which pass directly in front of their stars as seen from Earth, there are 644 distinct host stars; less than 200 have accurately known distances from Earth. 

This image shows the distances from Earth (center) to the stars (black dots) of transiting exoplanets. 

The inner dashed circle has a radius of 100 parsecs (about 326 light years) with the middle and outer circles corresponding to 500 parsecs (1,630 light years) and 1,000 parsecs (3,260 light years), respectively. 

The cluster of points to the lower right represents the transiting planets discovered by NASA's Kepler satellite. For each star, the straight lines extending from the circle indicate the current uncertainty of its distance from Earth. 

Credit: Michael Perryman

Unique planets and systems, such as planets that orbit in the opposite direction of their companions, can inspire years of research, Perryman said.

"It's not just about the numbers. Each of these planets will be conveying some very specific details, and many will be highly interesting in their own way," Perryman said.

"If you look at the planets that have been discovered until now, they occupy very specific regions of discovery space. Gaia will not only discover a whole list of planets, but in an area that has not been thoroughly explored so far."

More information: Michael Perryman, Joel Hartman, Gáspár Bakos and Lennart Lindegren. 2014. "Astrometric exoplanet detection with Gaia." Astrophysical Journal. Arti¬cle first pub-lished to the Cornell University arXiv preprint database: Nov. 6, 2014.

ESO ALMA: Planet-forming Lifeline Discovered in a Binary Star System

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. 

Image courtesy ESO/L. Calcada

For the first time, researchers using ALMA have detected a streamer of gas flowing from a massive outer disc toward the inner reaches of a binary star system.

This never-before-seen feature may be responsible for sustaining a second, smaller disc of planet-forming material that otherwise would have disappeared long ago.

Half of Sun-like stars are born in binary systems, meaning that these findings will have major consequences for the hunt for exoplanets.

The results are published in the journal Nature on 30 October 2014.

Anne Dutrey

A research group led by Anne Dutrey from the Laboratory of Astrophysics of Bordeaux, France and CNRS used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the distribution of dust and gas in a multiple-star system called GG Tau-A.

This object is only a few million years old and lies about 450 light-years from Earth in the constellation of Taurus (The Bull).

Like a wheel in a wheel, GG Tau-A contains a large, outer disc encircling the entire system as well as an inner disc around the main central star.

This second inner disc has a mass roughly equivalent to that of Jupiter.

Its presence has been an intriguing mystery for astronomers since it is losing material to its central star at a rate that should have depleted it long ago.

While observing these structures with ALMA, the team made the exciting discovery of gas clumps in the region between the two discs.

The new observations suggest that material is being transferred from the outer to the inner disc, creating a sustaining lifeline between the two.

"Material flowing through the cavity was predicted by computer simulations but has not been imaged before. Detecting these clumps indicates that material is moving between the discs, allowing one to feed off the other," explains Dutrey.

"These observations demonstrate that material from the outer disc can sustain the inner disc for a long time. This has major consequences for potential planet formation."

Planets are born from the material left over from star birth. This is a slow process, meaning that an enduring disc is a prerequisite for planet formation.

If the feeding process into the inner disc now seen with ALMA occurs in other multiple-star systems the findings introduce a vast number of new potential locations to find exoplanets in the future.

The first phase of exoplanet searches was directed at single-host stars like the Sun. More recently it has been shown that a large fraction of giant planets orbit binary-star systems.

Now, researchers have begun to take an even closer look and investigate the possibility of planets orbiting the individual stars of multiple-star systems.

The new discovery supports the possible existence of such planets, giving exoplanet discoverers new happy hunting grounds.

Emmanuel Di Folco, co-author of the paper, concludes: "Almost half the Sun-like stars were born in binary systems. This means that we have found a mechanism to sustain planet formation that applies to a significant number of stars in the Milky Way. Our observations are a big step forward in truly understanding planet formation."

LOFAR discovers largest carbon atoms outside our Milky Way

The starburst galaxy M82, the size of the carbon atoms and the observed spectral line. 

Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA)

An international team of astronomers under the guidance of graduate student Leah Morabito of Leiden Observatory has for the first time discovered the largest carbon atoms outside our Milky Way with the LOFAR radio telescope.

In the future astronomers will be able to measure how cold and dense the gas around these atoms is that influences star formation and the evolution of a galaxy. The results are published in the journal Astrophysical Journal Letters on October 28th.

"Carbon atoms are about half a million times smaller than the average thickness of a human hair, but they can be a billion times larger in the cold and sparse gas. The outermost electron is then orbiting the nucleus at a much larger distance," explains first author Morabito.

The outermost electron can be captured by an atom that is missing an electron. A spectral line will then be visible in the light spectrum. All spectral lines form the chemical fingerprint of an atom such as carbon.

Astronomers predicted in the 70's that the carbon spectral line would be detectable outside our galaxy. This first observation took 40 years to be made.

The line is hard to detect because it is too faint when the gas that is surrounding the atoms is too warm or too dense.

The cold, sparse gas is present in starburst galaxies, galaxies in which stars form at a high rate. For this reason the carbon spectral line is easier to detect in galaxies of this type.

Most radio telescopes observe at frequencies at which the carbon line can not be detected. Other telescopes are not sensitive enough to detect the spectral lines of the carbon atoms at low frequencies.

The LOFAR radio telescope, that stretches from the northeast of the Netherlands across Europe, is perfect for these kind of observations because of its frequency range and sensitivity.

Co-author Raymond Oonk from Leiden Observatory en ASTRON: "LOFAR is an unique telescope. This telescope opens up a new window on the universe."

The carbon atoms are present in the heart of the starburst galaxy M82, where 10 times more stars are being born in the same period as in our Milky Way.

The cold and sparse gas in this area impacts star formation, and the evolution of M82. "Since the co-discovery of the hydrogen 21-cm line by Dutch, American and Australian astronomers, we have been looking for a way to determine additional properties of the cold gas such as its temperature and density. It is fantastic that we now have found a way thanks to this carbon line.

We can now collect more and better observations, and compare them to predictions from theoretical models," says co-author Huub Röttgering (Leiden Observatory).

More information: "Discovery of Carbon Radio Recombination Lines in M82," Leah K. Morabito et al., Astrophysical Journal Letters, 28 October 2014 DOI: 10.1088/2041-8205/795/2/L33 . http://arxiv.org/abs/1410.1544

NuSTAR discovers impossibly bright dead star - First 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. 

Credit: NASA/JPL-Caltech/SAO/NOAO

Astronomers working with NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), led by Caltech's Fiona Harrison, have found a pulsating dead star beaming with the energy of about 10 million suns.

The object, previously thought to be a black hole because it is so powerful, is in fact a pulsar, the incredibly dense rotating remains of a star.

"This compact little stellar remnant is a real powerhouse. We've never seen anything quite like it," says Harrison, NuSTAR's principal investigator and the Benjamin M. Rosen Professor of Physics at Caltech.

"We all thought an object with that much energy had to be a black hole."

Dom Walton, a postdoctoral scholar at Caltech who works with NuSTAR data, says that with its extreme energy, this pulsar takes the top prize in the weirdness category. Pulsars are typically between one and two times the mass of the sun.

This new pulsar presumably falls in that same range but shines about 100 times brighter than theory suggests something of its mass should be able to.

"We've never seen a pulsar even close to being this bright," Walton says. "Honestly, we don't know how this happens, and theorists will be chewing on it for a long time."

Besides being weird, the finding will help scientists better understand a class of very bright X-ray sources, called ultraluminous X-ray sources (ULXs).

Harrison, Walton, and their colleagues describe NuSTAR's detection of this first ultraluminous pulsar in a paper that appears in the current issue of Nature.

"This was certainly an unexpected discovery," says Harrison. "In fact, we were looking for something else entirely when we found this."



This animation shows a neutron star, the core of a star that exploded in a massive supernova. 

This particular neutron star is known as a pulsar because it sends out rotating beams of X-rays that sweep past Earth like lighthouse beacons. 

Credit: NASA/JPL-Caltech

Earlier this year, astronomers in London detected a spectacular, once-in-a-century supernova (dubbed SN2014J) in a relatively nearby galaxy known as Messier 82 (M82), or the Cigar Galaxy, 12 million light-years away.

Because of the rarity of that event, telescopes around the world and in space adjusted their gaze to study the aftermath of the explosion in detail.

Besides the supernova, M82 harbours a number of other ULXs. When Matteo Bachetti of the Université de Toulouse in France, the lead author of this new paper, took a closer look at these ULXs in NuSTAR's data, he discovered that something in the galaxy was pulsing, or flashing light.

"That was a big surprise," Harrison says. "For decades everybody has thought these ultraluminous X-ray sources had to be black holes, but black holes don't have a way to create this pulsing."

More information: An Ultraluminous X-ray Source Powered by An Accreting Neutron Star, Nature, dx.doi.org/10.1038/nature13791189

Hubble finds jets and explosions in NGC 7793

Credit: ESA /Hubble & NASA, Acknowledgement: D. Calzetti (University of Massachusetts) and the LEGUS Team

This new image from the NASA/ESA Hubble Space Telescope shows NGC 7793, a spiral galaxy in the constellation of Sculptor some 13 million light-years away from Earth.

NGC 7793 is one of the brightest galaxies in the Sculptor Group, one of the closest groups of galaxies to the Local Group, the group of galaxies containing our galaxy, the Milky Way and the Magellanic Clouds.

The image shows NGC 7793's spiral arms and small central bulge.

Unlike some other spirals, NGC 7793 doesn't have a very pronounced spiral structure, and its shape is further muddled by the mottled pattern of dark dust that stretches across the frame.

The occasional burst of bright pink can be seen in the galaxy, highlighting stellar nurseries containing newly-forming baby stars.

Although it may look serene and beautiful from our perspective, this galaxy is actually a very dramatic and violent place.

Astronomers have discovered a powerful micro-quasar within NGC 7793, a system containing a black hole actively feeding on material from a companion star.

A micro-quasar is an object that has some of the properties of quasars in miniature. While many full-sized quasars are known at the cores of other galaxies, it is unusual to find a quasar in a galaxy's disk rather than at its center.

Micro-quasars are almost like scale models, they allow astronomers to study quasars in detail. As material falls inwards towards this black hole, it creates a swirling disk around it.

Some of the infalling gas is propelled violently outwards at extremely high speeds, creating jets streaking out into space in opposite directions.

In the case of NGC 7793, these jets are incredibly powerful, and are in the process of creating an expanding bubble of hot gas some 1,000 light-years across.

Monster Black Hole discovered in centre of Dwarf Galaxy

Astronomers have just discovered the smallest known galaxy that harbours a huge, supermassive black hole at its core.

The relatively nearby dwarf galaxy may house a supermassive black hole at its heart equal in mass to about 21 million suns.

The discovery suggests that supermassive black holes may be far more common than previously thought.

A supermassive black hole millions to billions of times the mass of the sun lies at the heart of nearly every large galaxy like the Milky Way.

These monstrously huge black holes have existed since the infancy of the universe, some 800 million years or so after the Big Bang.

Scientists are uncertain whether dwarf galaxies might also harbour supermassive black holes.

"Dwarf galaxies usually refer to any galaxy less than roughly one-fiftieth the brightness of the Milky Way," said lead study author Anil Seth, an astronomer at the University of Utah in Salt Lake City.

These galaxies span only several hundreds to thousands of light-years across, much smaller than the Milky Way's 100,000-light-year diameter, and they "are much more abundant than galaxies like the Milky Way," Seth said.

The researchers investigated a rarer kind of dwarf galaxy known as an ultra-compact dwarf galaxy; such galaxies are among the densest collections of stars in the universe.

"These are found primarily in galaxy clusters, the cities of the universe," Seth told reporters

This image shows a huge galaxy, M60, with the small dwarf galaxy that is expected to eventually merge with it.

Credit: NASA /Space Telescope Science Institute /European Space Agency

Now, Seth and his colleagues have discovered that an ultra-compact dwarf galaxy may possess a supermassive black hole, which would make it the smallest galaxy known to contain such a giant.

The astronomers investigated M60-UCD1, the brightest ultra-compact dwarf galaxy currently known, using the Gemini North 8-meter optical-and-infrared telescope on Hawaii's Mauna Kea volcano and NASA's Hubble Space Telescope. M60-UCD1 lies about 54 million light-years away from Earth.

The dwarf galaxy orbits M60, one of the largest galaxies near the Milky Way, at a distance of only about 22,000 light-years from the larger galaxy's center, "closer than the sun is to the center of the Milky Way," Seth said.

The scientists calculated the size of the supermassive black hole that may lurk inside M60-UCD1 by analyzing the motions of the stars in that galaxy, which helped the researchers deduce the amount of mass needed to exert the gravitational field seen pulling on those stars.

For instance, the stars at the center of M60-UCD1 zip at speeds of about 230,000 mph (370,000 km/h), much faster than stars would be expected to move in the absence of such a black hole.

This illustration depicts the supermassive black hole located at the center of the very dense galaxy M60-UCD1. 

It may weigh 21 million times the mass of our sun.

Credit: NASA, ESA, D. Coe, G. Bacon (STScI)

The supermassive black hole at the core of the Milky Way has a mass of about 4 million suns, taking up less than 0.01 percent of the galaxy's estimated total mass, which is about 50 billion suns.

In comparison, the supermassive black hole that may lie in the core of M60-UCD1 appears five times larger than the one in the Milky Way, and also seems to make up about 15 percent of the dwarf galaxy's mass, which is about 140 million suns.

"That is pretty amazing, given that the Milky Way is 500 times larger and more than 1,000 times heavier than the dwarf galaxy M60-UCD1," Seth said in a statement.

ESA Gaia team discovers their first Type Ia supernova

An artist’s impression of a Type Ia supernova, the explosion of a white dwarf locked in a binary system with a companion star. 

While other types of supernovas are the explosive demises of massive stars, several times more massive than the Sun, Type Ia supernovas are the end product of their less massive counterparts.

Low-mass stars, with masses similar to the Sun’s, end their lives gently, puffing up their outer layers and leaving behind a compact white dwarf. 

Due to their high density, white dwarfs can exert an intense gravitational pull on a nearby companion star, accreting mass from it until the white dwarf reaches a critical mass that then sparks a violent explosion. 

Credit: ESA/ATG medialab/C. Carreau

While scanning the sky to measure the positions and movements of stars in our Galaxy, ESA's Gaia satellite has discovered its first stellar explosion in another galaxy far, far away.

This powerful event, now named Gaia14aaa, took place in a distant galaxy some 500 million light-years away, and was revealed via a sudden rise in the galaxy's brightness between two Gaia observations separated by one month.

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ESA Gaia, which began its scientific work on 25 July, repeatedly scans the entire sky, so that each of the roughly one billion stars in the final catalogue will be examined an average of 70 times over the next five years.

"This kind of repeated survey comes in handy for studying the changeable nature of the sky," comments Simon Hodgkin from the Institute of Astronomy in Cambridge, UK.

Many astronomical sources are variable: some exhibit a regular pattern, with a periodically rising and declining brightness, while others may undergo sudden and dramatic changes.

"As ESA's Gaia goes back to each patch of the sky over and over, we have a chance to spot thousands of 'guest stars' on the celestial tapestry," notes Dr Hodgkin.

"These transient sources can be signposts to some of the most powerful phenomena in the Universe, like this supernova."

Dr Hodgkin is part of Gaia's Science Alert Team, which includes astronomers from the Universities of Cambridge, UK, and Warsaw, Poland, who are combing through the scans in search of unexpected changes.

It did not take long until they found the first 'anomaly' in the form of a sudden spike in the light coming from a distant galaxy, detected on 30 August.

The same galaxy appeared much dimmer when Gaia first looked at it just a month before.

"We immediately thought it might be a supernova, but needed more clues to back up our claim," explains Łukasz Wyrzykowski from the Warsaw University Astronomical Observatory, Poland.

Other powerful cosmic events may resemble a supernova in a distant galaxy, such as outbursts caused by the mass-devouring supermassive black hole at the galaxy centre.

However, in Gaia14aaa, the position of the bright spot of light was slightly offset from the galaxy's core, suggesting that it was unlikely to be related to a central black hole.

Supernova Gaia14aaa and its host galaxy. 

Credit: M. Fraser /S. Hodgkin /L. Wyrzykowski /H. Campbell /N. Blagorodnova /Z. Kostrzewa-Rutkowska /Liverpool Telescope /SDSS

Isaac Newton Telescope (INT)

To confirm the nature of this supernova, the astronomers complemented the Gaia data with more observations from the ground, using the Isaac Newton Telescope (INT) and the robotic Liverpool Telescope on La Palma, in the Canary Islands, Spain.

A high-resolution spectrum, obtained on 3 September with the INT, confirmed not only that the explosion corresponds to a Type Ia supernova, but also provided an estimate of its distance.

This proved that the supernova happened in the galaxy where it was observed.

"This is the first supernova in what we expect to be a long series of discoveries with Gaia," says Timo Prusti, ESA's Gaia Project Scientist.

Supernovas are rare events: only a couple of these explosions happen every century in a typical galaxy, but they are not so rare over the whole sky, if we take into account the hundreds of billions of galaxies that populate the Universe.

In addition to supernovas, Gaia will discover thousands of transient sources of other kinds, stellar explosions on smaller scale than supernovas, flares from young stars coming to life, outbursts caused by black holes that disrupt and devour a nearby star, and possibly some entirely new phenomena never seen before.

"The sky is ablaze with peculiar sources of light, and we are looking forward to probing plenty of those with Gaia in the coming years," concludes Dr Prusti.

Scientists discover seamount in Pacific ocean

Three-dimensional view of the southwest side of the seamount with 23-degree slopes. 

Credit: University of New Hampshire

University of New Hampshire scientists on a seafloor mapping mission have discovered a new seamount near the Johnson Atoll in the Pacific Ocean.

The summit of the seamount rises 1,100 meters from the 5,100-meter-deep ocean floor.

The seamount was discovered in August when James Gardner, research professor in the UNH-NOAA Center for Coastal and Ocean Mapping/Joint Hydrographic Center, was leading a mapping mission aimed at helping delineate the outer limits of the U.S. continental shelf.

Working aboard the R/V Kilo Moana, an oceanographic research ship owned by the U.S. Navy and operated by the University of Hawaii, Gardner and his team were using multibeam echosounder technology to create detailed images of the seafloor when, late at night, the seamount appeared "out of the blue." The team was able to map the conical seamount in its entirety.

The yet-unnamed seamount, located about 300 kilometers southeast of the uninhabited Jarvis Island, lies in one of the least explored areas of the central Pacific Ocean. Because of that, Gardner was not particularly surprised by the discovery.

"These seamounts are very common, but we don't know about them because most of the places that we go out and map have never been mapped before," he says.

Since only low-resolution satellite data exists for most of the Earth's seafloor, many seamounts of this size are not resolved in the satellite data but advanced multibeam echosounder missions like this one can resolve them. "Satellites just can't see these features and we can," Gardner adds.

While the mapping mission was in support of the U.S. Extended Continental Shelf Task Force, a multi-agency project to delineate the outer limits of the U.S. continental shelf, the volcanic seamount lies within the U.S. exclusive economic zone.

That means the U.S. has jurisdiction of the waters above it as well as the sediment and rocks of the seamount itself.

Three-dimensional view of the seamount area (southeast point of view and 3.5x vertical exaggeration) showing two volcanoes, in the foreground, with the discovered seamount in the background. 

Credit: University of New Hampshire

The seamount's impact remains unknown – for now. It's too deep (its summit lies nearly 4,000 meters beneath the surface of the ocean) to be a navigation hazard or to provide rich fisheries. "It's probably 100 million years old," Gardner says, "and it might have something in it we may be interested in 100 years from now."

Evidence of forming planet discovered 335 light years from Earth

This graphic is an artist’s conception of the young massive star HD100546 and its surrounding disk. 

Credit: P. Marenfeld & NOAO/AURA/NSF

An international team of scientists led by a Clemson University astrophysicist has discovered new evidence that planets are forming around a star about 335 light years from Earth.

The team found carbon monoxide emission that strongly suggests a planet is orbiting a relatively young star known as HD100546. The candidate planet is the second that astronomers have discovered orbiting the star.

Theories of how planets form are well-developed. But if the new study's findings are confirmed, the activity around HD100546 would mark one of the first times astronomers have been able to directly observe planet formation happening.

New discoveries from the star could allow astronomers to test their theories and learn more about the formation of solar systems, including our own, said Sean Brittain, an associate professor of astronomy and astrophysics at Clemson.

"This system is very close to Earth relative to other disk systems," he said. "We're able to study it at a level of detail that you can't do with more distant stars. This is the first system where we've been able to do this.

"Once we really understand what's going on, the tools that we are developing can then be applied to a larger number of systems that are more distant and harder to see."

For more than a decade, the team has focused some of Earth's most powerful telescopes on a disk-shaped cloud of gas and dust that surrounds HD100546.

The star is about 2.5 times larger and 30 times brighter than the sun, Brittain said. It's in the constellation Musca, or The Fly, and can only be seen from the Southern Hemisphere.

Brittain made three trips to Chile as far back as 2003 to gather data for the research. He used telescopes at the Gemini Observatory and the European Southern Observatory.

The new planet astronomers believe they have found what would be an uninhabitable gas giant at least three times the size of Jupiter, Brittain said. Its distance from the star would be about the same distance that Saturn is from the sun.

The team used a technique called "spectro-astrometry," which enables small changes in the position of the carbon monoxide emission to be measured.

A source of excess carbon monoxide emission was detected that appears to vary in position and velocity. The varying position and velocity are consistent with orbital motion around the star.

More information: Astrophysical Journal paper - dx.doi.org/10.1088/0004-637X/791/2/136, Preprint on Arxiv: arxiv.org/abs/1409.0804

Astrophysical Journal Letters paper - iopscience.iop.org/2041-8205/766/1/L1/ , Preprint on Arxiv: arxiv.org/abs/1302.7122

Scientists' research supports discovery mission into Asteroid cores

Dr. Richard S. Miller’s research could influence future asteroid mining operations and how we might deal with an impending strike.

Future asteroid mining operations and how we deal with an impending strike could be influenced by research on a potential NASA mission that's being done by team that includes a University of Alabama in Huntsville (UAH) scientist.

"If you identify an asteroid coming toward us, how you deal with it could depend on its density and structure," says Dr. Richard S. Miller, a UAH physics professor.

"Likewise, if this technique pans out, you could imagine sending out a specialized telescope to determine what the densities and interior structure of various asteroids are, then decide on the basis of that information what ones to mine."

Little is now known about asteroid interior density and composition. Are they uniform or are they what astrophysicists call differentiated bodies, having denser and less-dense areas?

"Asteroids are time capsules of the early solar system," Dr. Miller says.

"We know about their surface properties and we can also infer the mass of some asteroids. But what we want to do is actually probe the interior of asteroids and determine information about their structure, are there interior density gradients, what is the composition, is it solid or like Swiss cheese, and do they have cores or not? Is it a pile of rubble?

It turns out this structure can tell us a great deal about the conditions present during the early epochs of solar system formation and its evolution."

To find that out, the team's scientists will be borrowing imaging technology concepts developed for medicine and high-energy physics.

They are developing a mission concept to probe asteroids using a technique similar to human computerized tomography (CT) scans.

Dr. Miller is a co-investigator in a collaborative effort with the Planetary Science Institute (PSI), NASA's Johnson Space Center, the Universities Space Research Association's Arecibo Observatory (Arecibo/USRA) and the University of Houston to do the fundamental research and design that could lead to such a mission.

Led by principal investigator Dr. Tom Prettyman, senior scientist at PSI, the group has $500,000 in funding from the NASA Innovative Advanced Concepts (NIAC) Phase II program.

The team's two-year proposal, "Deep Mapping of Small Solar System Bodies with Galactic Cosmic Ray Secondary Particle Showers," is one of only five projects selected for funding.

Other funded collaborators include Dr. Steven Koontz, NASA Johnson Space Center; Dr. Michael Nolan, Arecibo/USRA; Dr. Lawrence Pinsky, University of Houston; and Dr. Mark Sykes, PSI.

By detecting the number of muons that pass through the object at left, scientists can discover and measure the size of its core, shown reconstructed at right. 

Credit: Richard S. Miller / UAH

The team proposes using ever-present cosmic rays to perform its measurements.

All objects in space are constantly bombarded by these particles, which are thought to be the remnants of massive supernovas and are primarily protons. On Earth, the atmosphere breaks them up and shields us from direct hits.

"In space, on contact with dense matter like the moon's surface or other airless planetary bodies, they interact within the first few centimeters of depth and create a shower of particles," Dr. Miller says.

Studying those interactions has provided us surface knowledge of asteroids. "But cosmic rays also contain muons, which are particles similar to electrons, but which can go a lot farther into the asteroid, in some cases up to one kilometer."

The idea is to position a telescope to orbit the asteroid and measure the number and trajectories of the muons passing through it.

"Muons are like an SUV," says Dr. Miller. "Once they are moving it is not easy to knock them off their course."

An asteroid composed of varying densities of material would return a different pattern than one with a single density, just as a CT scan differentiates between densities of structures in the body.

Likewise, if an asteroid has a denser core, it will stop muons from passing through and the telescope will detect the change.

That process is called muon tomography and is well understood. Developed in the 1950s, it was even used in the 1960s by Luis Alvarez to map the Pyramid of Chephren.

"What's different about a CT scan is that instead of using cosmic rays and muons to determine densities, a CT scan uses x-rays," Dr. Miller says.

To mature the concept, the scientists must first solve a number of fundamental challenges. They'll be using computer modeling to work on:

• Detailed estimates of the particle signatures, including muons and other radiations that will be present in deep space and in the neighbourhood of any asteroids;
• Doing the initial work on the muon telescope's design and operation. There are competing ideas, and the team will evaluate a variety of performance tradeoffs; 
• The development and implementation of advanced algorithms for asteroid structure reconstruction;
• Establishing the preliminary outlines of how a proposed NASA mission would be conducted, its feasibility and making predictions of the ultimate science return. 

"What it has to do is detect those muons and give us a direction they are coming from," Dr. Miller says of the telescope, but getting to that goal involves tradeoffs.

For example, the bigger the area the telescope can scan as it orbits, the less time it will take to get results encompassing an entire asteroid being studied.

But the greater the telescope's size, the more resources will be involved to launch the mission. Also, to tell where the muons are coming from, the telescope will have to be able to tell directional "up" from "down."

Dr. Miller says he was already exploring using muons to probe asteroids when he attended a conference and found that PSI's Dr. Prettyman was working on the same thing.

"This is a good story of how you had two independent groups who were both looking at the same idea," Dr. Miller says, "and we have joined forces to make a stronger project."