Astronomers discover extremely luminous nova

First nova ever found in Small Magellanic Cloud is studied in multiple wavelengths.

What might be one of the most luminous stars ever detected is actually a nova or explosion that occurred in a binary system consisting of a white dwarf and Sun-like star in the Small Magellanic Cloud.

White dwarfs are stellar remnants of stars not massive enough to have died in supernova explosions.

The Small Magellanic Cloud is a satellite galaxy of the Milky Way located about 200,000 light years away.

Using NASA’s Swift satellite, scientists at the University of Leicester discovered the extremely bright nova, caused by the white dwarf’s sucking of material from the regular star until critical pressure was reached, causing the sudden brightness increase.

Led by researchers at the South African Astronomical Observatory, the scientists also observed the nova with ground-based telescopes in several countries, including South Africa, Australia, and South America.

Designated SMCN 2016-10a, the nova, one of the brightest observed in any galaxy, was discovered on October 14, 2016.

The term “nova” means new. Centuries ago, astronomers thought these suddenly bright objects to be new stars as opposed to what they really are–dying old ones.

White dwarfs emit both visible light and high-energy X-rays. By studying their emissions in various wavelengths, scientists can determine their temperatures and compositions.

This is the first time astronomers have spotted a nova in the Small Magellanic Cloud. Approximately 35 are seen in the Milky Way each year.

“Swift’s ability to respond rapidly, together with its daily-planned schedule, makes it ideal for the followup of transients, including novae,” said Swift team X-ray analysis leader Kim Page of the University of Leicester.

“It was able to observe the nova throughout its eruption, starting to collect very useful X-ray and UV data within a day of the outburst first being reported. The X-ray data were essential in showing that the mass of the white dwarf is close to the theoretical maximum; continued accretion might cause it eventually to be totally destroyed in a supernova explosion.”

Paul Kuin of the Mullard Space Science Laboratory at University College London, who organized the UV data, described the ability to observe the nova in multiple wavelengths as key to this being the most comprehensive nova study ever conducted.

Findings of the study have been published in Monthly Notices of the Royal Astronomical Society.

Auroras at Jupiter’s poles act independently

Researchers take advantage of rare opportunity to observe polar regions through Juno mission and space telescopes.

Auroras in Jupiter’s north and south polar regions act independently of one another, according to observations conducted by a study team using the European Space Agency’s (ESA) X-MM-Newton telescope and NASA’s Chandra X-ray Observatory.

Researchers at University College in London and at the Harvard-Smithsonian Center for Astrophysics led a study of high-energy X-ray auroras at both of Jupiter’s poles and were surprised to learn that unlike auroras on the poles of other planets, those at Jupiter’s poles do not mirror one another but pulse independently.

Activities of Earth’s north and south pole auroras mirror one another. Saturn does not appear to experience any X-ray auroras.

X-ray pulses at Jupiter’s south pole occur regularly every 11 minutes while those at its north pole are chaotic, with unpredictable increases and decreases in brightness.

“We didn’t expect to see Jupiter’s X-ray hot spots pulsing independently, as we thought their activity would be coordinated through the planet’s magnetic field,” explained study lead author William Dunn of both UCL Mullard Space Science Laboratory in the UK and the Harvard-Smithsonian Center for Astrophysics.

“We need to study this further to develop ideas for how Jupiter produces its X-ray aurora, and NASA’s Juno mission is really important for this.”

The researchers observed Jupiter using both space observatories in May and June of 2016 and in March 2007 to map the planet’s X-ray emissions and identify X-ray hot spots at its poles.

NASA’s Juno spacecraft, which arrived at Jupiter in 2016, does not have a science instrument capable of detecting X-rays; however, it is collecting other data at the polar regions that scientists hope to combine with the X-MM and Chandra data to better understand the planet’s auroras.

Scientists are fortunate that Juno is studying both of Jupiter’s poles at the same time, making it possible for them to compare activity at the poles with the giant planet’s complex magnetic interactions, emphasized study co-author Graziella Banduardi-Raymont of UCL Space and Climate Physics.

“If we can start to connect the X-ray signatures with the physical processes that produce them, then we can use those signatures to understand other bodies across the universe, such as brown dwarfs, exoplanets, or maybe even neutron stars,” Dunn stated.

One theory the researchers hope to test as they observe Jupiter’s polar activity over the next two years is that the northern and southern auroras form separately as a result of interactions between the planet’s magnetic field and the solar wind.

A paper discussing the findings has been published in the journal Nature Astronomy.

 

Astronomers find another potentially habitable planet 11 light-years away

Astronomers discovered a potentially Earth-like planet just 11 light-years from Earth. They said that it is at the right distance from its star to have liquid water and a climate mild enough to sustain life.

Astronomers in Chile have discovered a planet that may be capable of supporting life and is only 11 light-years away from Earth. In a report soon to be published in Astronomy and Astrophyics, they wrote that the planet could have liquid water and a temperature close to that of Earth.

The astronomers named the planet Ross 128B, after its star, a red dwarf called Ross 128. The planet and star are 20 times closer to each other than Earth is to the sun, according to the researchers, but they said that Ross 128’s radiation and heat are so much lower than our sun’s that the planet could still have an Earthlike temperature.

Xavier Bonfils, of the Institute of Planetology and Astrophysics in France, discovered the new planet in 2016 with Nicola Astudillo-Defru of the Geneva Observatory in Switzerland. Astudillo-Defru said that he and Bonfils made their discovery after a decade of “intensive monitoring” at the La Silla Observatory in Chile.

Ross 128B is the second-closest exoplanet to Earth that astronomers have found so far, according to Bonfils. He said that the closest is Proxima B, which orbits another red-dwarf star Proxima Centauri. Proxima Centauri emits much more radiation than Ross 128, however, and Proxima B receives too much of it to be conducive to life. Bonfils said that Ross 128 B looks much more promising, by comparison, but much would depend on the planet’s own ground conditions.

“We still need to know what the atmosphere of Ross 128 b is like. Depending on its composition and the reflectivity of its clouds, the exoplanet may be life friendly with liquid water as the Earth, or sterile like Venus,” Bonfils told the BBC.

Astronomers find remnant of 600-year-old nova

Based on the Korean astronomers’ description of the phenomenon, scientists today believe the outburst occurred in a binary system that contained a dead, highly dense white dwarf star and a companion.

A three-decade search for the remnant of a nova recorded by Korean astronomers almost 600 years ago has finally succeeded in finding the location of the stellar remnant.

Michael Shara, astrophysics coordinator at New York’s American Museum of Natural History, said the hunt for Nova Scorpii AD 1437 took so long because Korean records did not assign numbers or names to nearby stars, resulting in his team inadvertently looking  in the wrong location.

Novae are nuclear explosions that occur at the end stages of massive stars’ lives. Unlike the more powerful supernovae, which completely destroy their precursor stars, standard novae leave the remains of their parent stars intact.

Fifteenth-century Korean astronomers recorded what they believed was a new star that appeared on March 11, 1437 near a known star in the tail of the constellation Scorpius. The bright “new” star was visible for two weeks before disappearing.

Based on the Korean astronomers’ description of the phenomenon, scientists today believe the outburst occurred in a binary system that contained a dead, highly dense white dwarf star and a companion.

Over time, white dwarfs funnel material out of their companion stars, eventually causing them to explode.

Known as cataclysmic variables, binary systems composed of a white dwarf and a regular star experience many novae over time and possibly smaller explosions known as dwarf novae.

By analyzing data collected by the South African Large Telescope and Las Campanas Observatory’s Swope and du Pont telescopes, along with reviewing digital images of photographic plates of the sky taken by Harvard University for more than 100 years, the research team located debris from the nova in the constellation Scorpius.

Calculations of neighboring stars’ motions over the last six centuries confirmed a binary system once resided in the location where the nova was originally seen.

Evidence of dwarf novae in this location on photographic plates from the 1930s and 1940s suggests the binary system is producing both classical and dwarf novae.

The researchers, who published their findings in the journal Nature, hope to image the nova to find out what it looks like now as well as locate several additional novae recorded in history to confirm that classical and dwarf novae have common origins.

Alien civilizations may be trying to contact us

Some scientists are reporting “fast radio bursts” that might be alien civilizations trying to communicate.

Some scientists are reporting “fast radio bursts” that might be alien civilizations trying to communicate.

“Fast radio bursts” are brief and intense pulses of radio waves that are picked up from outer space. Experts are almost certain that there is no way that these radio waves could have originated from Earth but are completely uncertain of what their cause is. A renaissance in radio astronomy has occurred since the discovery of the fast radio burst phenomenon. Some of the bursts have certain scientists speculating that the FRB’s are signals being transmitted by distant alien civilizations.

An international team of astronomers recently uncovered the brightest fast radio burst to date. Their detection was named FRB 150807 because of its discovery date. It was a radio wave that lasted less than half a millisecond, which is .1 percent of the amount of time it takes a human being to blink its eyes.

Their findings were published in a study in Science called “The magnetic field and turbulence of the cosmic web measured using a brilliant fast radio burst” and involved over a dozen scientists. The astronomers reported in the study that they had pinpointed the origin of the FRB to an area smaller than any other study before it. Their study was published only days after another study , “Discovery of a transient gamma ray counterpart to FRB 131104”, reported having seen gamma rays, or highly energetic electromagnetic radiation, closely associated with their fast radio burst.

A SpaceX capsule has successfully docked with the International Space Station

Despite the challenges, SpaceX was back at it in January with the successful launch of Falcon 9 which took place at Vandenberg Air Force Base in California.

A SpaceX capsule has successfully docked with the International Space Station.

Just before 6 am, the Dragon space capsule was captured by a NASA Commander and European Space Agency Engineer, docking with the International Space Station(ISS). The great footage was captured using a robotic arm.

A previous attempt had to be aborted after the capsule developed navigational problems. This launch is the 10th Space mission that SpaceX has flown for NASA, and it was carrying around 5,000 pounds of supplies and experiments for the six Astronauts who are on board the capsule. They include two Americans, three Russians, and one Frenchman.

In the past two years, SpaceX has encountered two major setbacks in its quest to dock at the ISS; in June 2015, a supply mission exploded and burst into flames just a few minutes after launching. While in September, another rocket exploded while being fuelled at the Kennedy Space Center.

Despite the challenges, SpaceX was back at it in January with the successful launch of Falcon 9 which took place at Vandenberg Air Force Base in California. It was loaded with 10 Iridium communication satellites.

This Sunday’s launch did experience any hurdles as well. The journey took four days, and the Dragon spaceship approached the space station from below, pausing at some points for status checks from the ground crew.

After the cargo has been unloaded in Space by the capsules crew, it will be packed with trash and sent back to Earth. It is expected to crash into the Pacific Ocean just off Mexico around March.

Asteroid-bound spacecraft slingshots past Earth

Gravity assist will alter its trajectory while saving fuel.

Traveling through space at 19,000 miles (30,000 km) per hour, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft is flying by Earth on Friday, September 22, using the planet’s gravity to redirect its path to the asteroid Bennu.

Launched a year ago from Cape Canaveral on an Atlas V rocket, the spacecraft will arrive at Bennu in November 2018. It will orbit the asteroid, identify ideal surface locations for collecting samples, then use a robotic arm to reach into the surface to take the samples and store them inside a special collection device.

In 2021, OSIRIS-REx will head back toward Earth where, two years later, it will return the samples by parachuting a canister containing them into Utah.

From there, they will be taken to NASA’s Johnson Space Center in Houston, where scientists will analyze them for organic molecules and materials that make up the building blocks of life.

An Earth flyby is necessary to propel OSIRIS-REx to its target because a direct flight would have required additional fuel that would have mandated it launch on a larger rocket.

“It was a way to substantially save on resources, either on the spacecraft or on the launch vehicle, or both,” said mission principal investigator Dante Lauretta of the University of Arizona.

The flyby, which takes the probe within about 11,000 miles (17,000 km) of Earth’s surface, will increase its velocity by 8,400 miles per hour.

NASA will be out of contact with the probe for about an hour during closest approach while it flies over Antarctica.

“OSIRIS-REx uses the Deep Space Network to communicate with Earth, and the spacecraft will be too low relative to the southern horizon to be in view with either the Deep Space tracking station at Canberra, Australia, or Goldstone, California,” explained Mike Moreau, NASA Goddard Space Flight Center flight dynamics system lead.

The spacecraft will photograph the Earth and Moon with its three imaging cameras for as long as 10 days after the flyby.

Earth data will be collected by its thermal emission spectrometer and visible and infrared spectrometer for instrument calibration purposes.

Members of the mission team plan to release photographs collected by the probe on Tuesday, September 26.

ALMA photographs debris ring around young star Formalhaut

Disk’s chemical composition is strangely similar to that of comets in our solar system.

Using the Atacama Large Millimeter/submillimeter Array (ALMA), a team of scientists has captured the first ever complete image of a ring of icy dust surrounding the young star Formalhaut.

The complete millimeter-wavelength of the ring reveals it to be a well-defined structure of dust and gas with a composition surprisingly similar to that of comets in our solar system.

Located approximately 25 light years away, Formalhaut has a planet initially discovered in 2008. It is one of only about 20 nearby star systems whose orbiting planets have been directly imaged.

The debris ring is approximately two billion kilometers wide at a distance of about 20 billion kilometers from the star.

At about 440 million years old, the system is just one-tenth as old as our solar system and may be experiencing its own version of the Late Heavy Bombardment that ours underwent about four billion years ago, a period characterized by asteroids and comets left over from the system’s formation repeatedly slamming into its planets.

Impacts of exocomets crashing into one another in the outer regions of the Formalhaut system likely created the debris ring, scientists believe.

A previous attempt to image the debris ring with ALMA in 2012, when the telescope was still in the process of being built, revealed just half of the disk but already hinted at chemical similarities with our solar system’s comets.

Now, “ALMA has given us this staggeringly clear image of a fully formed debris disk. We can finally see the well-defined shape of the disk, which may tell us a great deal about the underlying planetary system responsible for its highly distinctive appearance,” noted Meredith MacGregor of the Harvard-Smithsonian Center for Astrophysics in Cambridge, MA, and lead author of two papers on the subject scheduled for publication in the Astrophysical Journal.

With the help of computer modeling, the researchers were able to pinpoint the exact location and shape of the disk. Based on its narrow shape, they believe it to be the product of the gravitational influence of planets orbiting the star.

Interestingly, the debris disk contains approximately the same high levels of both carbon monoxide and carbon dioxide found in our own solar system’s comets.

Impacts among numerous exocomets could be releasing these gases.

“This chemical kinship may indicate a similarity in comet formation conditions between the outer reaches of this planetary system and our own,” noted Luca Matra of the University of Cambridge in the UK and lead author of one of the two papers on the discovery.

 

 

Organics on Ceres are likely native

Distribution of organic materials is inconsistent with delivery by comets or asteroids.

Organic materials found on dwarf planet Ceres by NASA’s Dawn spacecraft are likely native to the small world, according to research by scientists at the Southwest Research Institute (SwRI) in San Antonio, Texas.

The researchers specifically focused on a localized region of organic-rich material near Ernutet Crater, a 32-mile- (52-km-) wide opening on Ceres’ northern hemisphere.

Two origins are theorized for these organic materials or carbon-based compounds. They could have been brought to Ceres by impacting asteroids or comets after the dwarf planet formed 4.5 billion years ago, or they could have been synthesized through an internal process on the dwarf planet.

Located at the boundary of the solar system’s rocky planets and gas giants, Ceres is composed of clays and both sodium- and ammonium-carbonates, all of which indicate the small planet underwent complex chemical evolution.

“Earlier research that focused on the geology of the organic-rich region on Ceres were inconclusive about their origin,” explained Simone Marchi, an SwRI principal investigator who presented the findings Wednesday at a press conference held at the American Astronomical Society’s 49th Division for Planetary Sciences Meeting in Provo, Utah.

“Recently, we more fully investigated the viability of organics arriving via an asteroid or comet impact.”

Through computer simulations, scientists considered a range of variables, including the sizes and velocities of impacting objects.

The simulations indicated comet-like objects that hit Ceres at very high velocities would have had their organic materials destroyed by a mechanism known as shock compression, in which total pressure is lost.

Impacting asteroids, which would have lower velocities, would hold onto between 20 and 30 percent of their organic materials, depending on the angle at which they hit.

However, the localized distribution of organic materials on Ceres is not consistent with what would be seen if those organics had been delivered by small asteroids from the belt between Mars and Jupiter.

While researchers admit they still do not have all the pieces of the puzzle when it comes to Ceres’ organics, “These findings indicate that the organics are likely to be native to Ceres,” Marchi said.

Ceres is geologically differentiated, with a rocky core and icy mantle, and may harbor a subsurface ocean that could possibly be home to microbial life.

Asteroid that will fly close to Earth on Thursday poses no danger

Astronomers will have opportunity to observe a complete rotation of the object in just one night.

An asteroid discovered five years ago will come within 31,000 miles (50,000 km) of Earth on Thursday, October 12, but poses no impact danger to our planet.

Just a week after its discovery by Hawaii’s Pan-STARRS, asteroid 2012 TC4 passed within 58,900 miles (94,800 km) of Earth, and observation over time indicates it has made many such approaches in the past.

Approximately the size of the meteor that hit Chelyabinsk, Russia, in 2013, with a diameter ranging from 26 to 85 feet (8 to 26 meters), 2012 TC4 has an elongated shape, rotates at a high speed, and orbits the Sun every 1.67 years. Its distance from the Sun is around 1.4 AU or astronomical units, with one AU equal to the average Earth-Sun distance or 93 million miles.

“There is no hazard in its upcoming pass or anytime in the near future,” said Alan Harris, formerly a researcher at NASA’s Jet Propulsion Laboratory (JPL).

Early calculations conducted this summer by JPL led scientists to believe 2012 TC4 could come as close as 4,200 miles (6,800 km). Because these calculations were based on just seven days of tracking the asteroid, later studies by the European Space Agency’s (ESA) Oliver Hainaut, Detlef Koschny, and Marco Micheli using the European Southern Observatory (ESO) concluded its approach would not be that close.

According to JPL, “The new calculations indicate that TC4 will fly safely past our planet on Oct. 12, at a distance of about 43,500 km (27,000 miles) above the surface, or about one-eighth of the distance to the Moon.”

Astronomers around the world will be able to observe the asteroid, which will have a brightness of approximately magnitude 14, when it makes its close approach at 5:41 UTC (1:41 AM EDT) on Thursday.

Because 2012 TC4 has such a fast rotation rate, observers should be able to watch a full rotation in just one night, Harris said.

The International Asteroid Warning Network, a UN-sanctioned organization that focuses on collecting data on asteroids that pose potential threats to Earth, will also be following it.

While there is no chance of 2012 TC4 hitting the Earth, even if it did impact, it is too small to cause major damage and would likely land harmlessly over one of Earth’s oceans, Harris noted.