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.

Black holes aren’t surrounded by “firewalls,” study says

A new study uses string theory to examine black holes and provide evidence contrary to theories that suggest black hole “firewalls.”

Researchers from The Ohio State University suggest that black holes aren’t surrounding by a “firewall,” and are essentially perpetually growing balls of string.

Although some physicists suggest that there is a “firewall” around black holes that can incinerate anything sucked into its gravitational pull, the new study examines what would happen if an electron was sucked into a standard black hole.

“The probability of the electron hitting a photon from the radiation and burning up is negligible, dropping even further if one considers larger black holes known to exist in space,” said Samir Mathur, a professor of physics at Ohio State.

The team came to their conclusion through months of mathematical research built on string theory, which posits that the universe is composed of string-like tubes of energy that exist at a subatomic level.

“The question is ‘Where does the black hole grab you?’ We think that as a person approaches the horizon, the fuzzball surface grows to meet it before it has a chance to reach the hottest part of the radiation, and this is a crucial finding in this new physics paper that invalidates the firewall argument,” Mathur said.

“Once a person falling into the black hole is tangled up in strings, there’s no easy way to decide what he will feel,” he continued.”

“The firewall argument had seemed like a quick way to prove that something falling through the horizon burns up. But we now see that there cannot be any such quick argument; what happens can only be decided by detailed calculations in string theory.”

Young galaxy’s halo reveals clues to evolution and growth of ancient galaxies

The halo of a young galaxy Q2343-BX418 could shed light on the evolution and growth of the universe’s early galaxies.

Researchers believe that they have discovered a new method of unlocking the mysteries underlying the formation and evolution of the first galaxies. By examining Q2343-BX418, a small young galaxy about 10 billion light years from the Earth, the team believes they can reveal how galaxies looked following the birth of the universe.

Not only that, but the galaxy possesses a gas halo that is emits a certain type of light that is of great interest to astronomers.

“In the last several years, we’ve learned that the gaseous halos surrounding galaxies glow with a particular ultraviolet wavelength called Lyman alpha emission,” said the study’s lead author Dawn Erb. “There are a lot of different theories about what produces this Lyman alpha emission in the halos of galaxies, but at least some of it is probably due to light that is originally produced by star formation in the galaxy being absorbed and re-emitted by gas in the halo.”

“Most of the ordinary matter in the universe isn’t in the form of a star or a planet, but gas,” Erb said. “And most of that gas exists not in galaxies, but around and between them.”

The halo is the location where gas enters and exits the galaxy. It also fuels galaxies, and sometimes the gas within a galaxy can shift into the halo. The process of gas flowing in and out of these regions is what influences stars and their fates.

“The inflow of new gas accreting into a galaxy provides fuel for new star formation, while outflows of gas limit a galaxy’s ability to form stars by removing gas,” Erb said. “So, understanding the complex interactions happening in this gaseous halo is key to finding out how galaxies form stars and evolve.”

Notably, the study harnessed the power of the Keck Cosmic Web Imager (KCWI) from the Keck Observatory.

“Our study was really enabled by the design and sensitivity of this new instrument,” Erb said. “It’s not just an ordinary spectrograph—it’s an integral field spectrograph, which means that it’s a sort of combination camera and spectrograph, where you get a spectrum of every pixel in the image.”

The findings were published in Astrophysical Journal Letters.

A galactic collision influenced history of the Milky Way

According to a team of scientists, the Milky Way evolved about 10 billion years ago when it collided head-on.

As the Milky Way evolved about 10 billion years ago, it collided head-on with another smaller galaxy. That cataclysm changed its structure forever.

Two new studies describe the overlooked evidence for this event. “There’s debris everywhere,” said Vasily Belokurov, an astronomer at the University of Cambridge and a leader of one of the two teams.

To uncover evidence of the collision, astronomers had to sift through multitudinous sources of surviving information. They can use it to compose a story consistent with the available evidence.

Both research teams used information from the European Space Agency’s Gaia space telescope. It has been gathering biographies of millions of stars for several years.

The experiments involved creating high-resolution and multidimensional maps of the Milky Way and using them to find anomalous populations of old stars that seem to retain a memory of the collision. The team found a large number of stars that do not move coordinated with the galaxy’s rotation. Instead, they move in radial orbits, streaming toward or away from the center of the galaxy.

Belokurov’s group also modeled different collision scenarios, as well as a possible quieter history without significant collisions. An impact of a small “dwarf” galaxy could have deposited a cloud of stars like the ones seen today, they discovered.

The collision theory could help resolve a continuing question about the Milky Way’s structure. Its spiral disk of stars is inclusive of two parts: a thin dense region encompassed by a thick diffuse region.

Astronomers believe asteroids might be remnants of destroyed worlds

A majority of the millions of bodies in the inner asteroid belt may be shrapnel from planetesimals.

Scientists thought asteroids were leftovers of planet formation. The also used to believe they were chunks of material that never made it to planet size.

According to a study published on July 2, 2018 in the journal Nature Astronomy, the asteroids were once pieces of worlds too. A majority of the half-million bodies in the inner asteroid belt may be shrapnel from planetesimals, five parent bodies, scientists say.

The lost world’s tangled orbits doomed them to collide and produce fragments that also collided. The collisions produced even more fragments in a cataclysmic cascade that has been occurring for more than 4 billion years.

The study’s lead author is astronomer Stanley Dermott of the University of Florida. He did not set out to probe a mystery of solar system formation. He and his team were looking at data on the dynamics of bodies in the inner asteroid belt.

When Dermott began to look through a database of near-Earth objects, he noticed something odd about many large asteroids. Their orbits were inclined relative to the solar system’s plane.

There is an important implication of the idea that asteroids are fragments of larger bodies because it means asteroids are big, says David Nesvorny, a planetary scientist at Southwest Research Institute.





Astronomers see the birth of planet for the first time

The observed PDS 70 star is 5.4 million years old and 1.25 wider than the sun.

Astronomers for the first time have seen the birth of a giant planet during its development, according to a report by SyfyWire. While astronomers have seen young planets and stars during the birth phase, but never before have they seen a clear picture of a planet in flagrante delicto – caught in the act – of being born.

For background, the planet that was observed is a star called PDS 70 that is located approximately 370 light years away. The star is part of a group of young stars known as the Scorpius Centaurus Association. These stars are in the processing stage and are the closest known group in the galaxy.

The observed star is estimated at 5.4 million years old, which is considered relatively young. The star has approximately 0.76 times the mass of the sun but is a full 1.25 times wider. It shines with only one-third of the sun’s brightness.

In 2002, it was observed to be surrounded by a disk material, which is a sign of young stars. This disk material uses small grains which collide and stick together. They eventually grow and become bigger and bigger, essentially forming the star into a protoplanet and then a new planet.

Milky Way’s cosmic jazz can now be heard online

A researcher has turned the Milky Way into a jazz composition using an algorithm to express its gases.

Mark Heyer of the University of Massachusetts Amherst has created an algorithm that expresses the gas movement in the Milky Way’s disc as music, according to Science Alert. The resulting composition has jazz-like tones, and has been titled the Milky Way Blues.

“This musical expression lets you ‘hear’ the motions of our Milky Way galaxy,” Heyer said. “The notes primarily reflect the velocities of the gas rotating around the centre of our galaxy.”

Heyer mapped 20 years of radio telescope data on the Milky Way’s gas using a pentatonic minor scale. The gases exist in three phases: molecular, atomic, and ionized. They can also move in specific directions — towards us or away from us.

Using a pentatonic minor scale, he mapped 20 years of radio telescope data on gas in the Milky Way to musical notes and instruments.

The gases were turned into musical instruments based on their spectra. For example, molecular gases were turned into pianos and woodblocks, atomic gases into acoustic basses, and ionized gases into the saxophones. Gas moving towards us were turned into high notes, and gas moving away from us were turned into low notes. The longer the note, the stronger the emission line.

“Each observation is represented by a line showing where the telescope was pointing and the positions of the circles along a line show the locations of the gas in the galaxy responsible for the played notes,” Heyer said.

Heyer’s composition is featured on Astronomy Sound of the Month.

Study suggests that ancient gravitational force rippled through our galaxy

Preliminary data suggests that the Milky Way was hit by an ancient gravitational force that rippled through it.

New data suggests that a strong gravitational force sent ripples through the Milky Way approximately 300 to 900 million years ago, according to Gizmodo. The findings come from the Gaia mission’s data drop that happened last week—in particular, one paper that describes a potential gravitational force that could have affected our galaxy in an ancient time, like a stone thrown into a pond.

“We have here provided the clearest evidence that our own Galaxy disk has suffered from perturbations, bringing it to an out-of-equilibrium state, which may well be due to the interaction with an external satellite galaxy,” reads the paper, which has yet to be peer-reviewed.

Using data on the apparent motion of 1.3 billion stars in the sky and actual velocities for over 7 million stars, the research team studied how the star velocities vary with position. The motion revealed that they are likely recovering for a gravitational force a few hundred million years ago, which is fairly recent in the universe’s terms.

The gravitational force might have originated from a close approach from the Sagittarius Dwarf Galaxy, which is a collection of stars that orbits the Milky Way from around 70,000 light years away..

“This work shows that the stellar disk of the Milky Way is a dynamically active place, where spiral arms and the Galactic bar leave their marks on the orbits of stars like ripples in a pond—a pond that has perhaps recently felt the splash of a small stone in the form of a merging dwarf galaxy,” said Stacy McGaugh from Case Western Reserve University, who wasn’t involved in the study. “It is a living and breathing beast that is sensitive to be poked and prodded and even tickled a little bit.”

The findings are available on preprint repository arXiv.

Scientists believe dozens of black holes could lie at center of Milky Way

A new study suggests the presence of a dozen black holes around the Milky Way’s supermassive black hole.

Scientists believe that a dozen black holes might lie at the center of the Milky Way, according to BBC News. The new data supports the idea that the “supermassive” black holes that lie at the centre of galaxies are surrounded by numerous smaller ones.

The data used archival data from NASA’s Chandra X-ray telescope. The Columbia University research team found a dozen inactive, low-mass “binary” systems where a star obits a black hole

The supermassive black hole at the center of the Milky Way, named Sagittarius A* (Sgr A*), appears to be surrounded by a halo of gay and dust. This makes it the perfect breeding ground for massive stars, which could turn into black holes following death.

“The galactic centre is so far away from Earth that those bursts are only strong and bright enough to see about once every 100 to 1,000 years,” said Charles Hailey, a researcher from Columbia University and lead author of the study.

The discovery that there are between 300 to 500 low-mass binaries and 10,000 isolated low-mass black holes around Sgr A* is significant.

“It is going to significantly advance gravitational wave research because knowing the number of black holes in the centre of a typical galaxy can help in better predicting how many gravitational wave events may be associated with them,” Hailey said.

The findings were published in Nature.