Cold, white dwarf star may have a giant diamond core

Astronomers have discovered a white dwarf star that could be the coldest of its type ever detected. The dwarf star resides alongside the pulsar PSR J2222-0137 and could hold at its core a diamond the size of the earth.

Estimates would place the star's age at 11 billion years, roughly the same as the Milky Way galaxy.

White dwarf stars, because of their small size, appear extremely faint, and can be incredibly difficult to spot from Earth – even with high-powered telescopes. The team, drawing on data collected from the National Radio Astronomy Observatory (NRAO), Green Bank Telescope and Very Long Baseline Array (VLBA) observatories said they were able to detect the extremely faint star some 900 light years away by observing the gravitational effect the star had on its companion pulsar's radio signals.

Despite being slightly more massive (1.05 times) than the Sun, the dwarf is believed to be 5,000 times cooler. The 3,000 kelvin temperature would possibly make it the coldest known white dwarf. At the heart of the star, say researchers, is a mass of crystallized carbon described as "diamond-like" and roughly the size of the Earth, formed from the center of the collapsed star.

The massive rock wouldn't be the first time astronomers have spotted a space-diamond orbiting pulsar. In 2011, Australian researchers used a similar detection method to spot a crystallized carbon mass around the pulsar PSR J1719-1438.

Far-off galaxies emit X-ray signals characteristic of dark matter

NASA scientists have detected unidentified particles emitting from a galaxy 250 million light-years away. The particles were received as X-ray signals which demonstrate theorized behaviors of dark matter- a substance which comprises 85 percent of all matter in the entire universe.

The signals were confirmed by both NASA’s Chandra X-ray observatory and the European Space Agency’s XMM-Newton instrument.

Scientists believe that the X-rays might contain part of dark matter’s hypothesized composition: a type of decayed X-ray particle, called a sterile neutrino. A theorized type of neutrino, sterile neutrinos are possible dark matter components which emit X-rays when they decay. However, scientists have yet to confirm whether the X-rays detected from this group of galaxies demonstrates the projected behaviors of dark matter.

“Our next step is to combine data from Chandra and JAXA’s [the Japanese Aerospace Exploration Agency's] Suzaku mission for a large number of galaxy clusters to see if we find the same X-ray signal,” said Adam Foster, an author of the study.

Dark matter does not emit or absorb light, making it difficult for astronomers to detect beyond observing its gravitational effects. The possibility of finding sterile neutrinos has excited scientists.

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Astronomers stumble upon rare trio of supermassive blackholes

Where two distant galaxies collide, three supermassive black holes engage in a gravitational dance. Two of the black holes embrace in a tight orbit, spinning out jets of gas, while the third waits off to the side.

Observations of the trio demonstrate that swirling jets can help astronomers find hidden black hole pairs. The finding also suggests that these pairs may be more common than previously thought.

Every large galaxy appears to harbor a central supermassive black hole, a pileup of the corpses of huge stars. These black holes, which can weigh well over a billion suns, appear to build up over time from collisions between galaxies. As two galaxies merge, their central black holes find one another, spiral together and eventually combine into one giant black hole.

Roger Deane, an astrophysicist at the University of Cape Town in South Africa, and colleagues stumbled upon the black hole trio while studying galaxies that emit a lot of radio light. The researchers knew of a galaxy that holds two black holes, which were first discovered three years ago and are separated by about 24,000 light-years. What Deane’s team figured out is that one of those black holes is actually two black holes, crowded together at just 450 light-years apart, according to the team, reports Nature.

Researchers think that compact binary supermassive black holes may be strong sources of gravitational waves. As they orbit each other, the black holes radiate gravitational energy, which should send out ripples in the fabric of space. In principle, these gravitational waves may be detectable by instruments on Earth, like the Laser Interferometer Gravitational-Wave Observatory, but physicists have not directly detected the waves. A direct observation of gravitational waves would confirm a prediction of Einstein’s theory of general relativity and also provide a way to explore the many phenomena that emit almost no light. A collection of compact black hole pairs could help researchers know where to look.

To find out more about how Deane's team distinguished between the two close-together black holes, click here.

Small galaxies play 'bigger' role in star creation: Study

Dwarf galaxies actually play a larger role in star creation than previously thought. Astronomers using the Hubble Space Telescope estimated the rate at which stars were created in the tiny galaxies.

Over the past decades, astronomers have been studying the link between the mass of a galaxy and the rate at which stars are formed.

A majority of the studies focused on large and medium galaxies paying little attention to the dwarfs. Hakim Atek of Polytechnique Fédérale de Lausanne in Switzerland says astronomers have always suspected that the small galaxies do contribute to the initial wave of star formation. But this study is the first to quantify the effect that they have. The team used the Wide Field Camera 3 (WFC3) on the orbiting observatory to get data.

Tiny galaxies were common some 10 billion years ago. Astronomers classify some of them as starburst galaxies which are galaxies that produce starts at rates higher than normal. Due to their size, it wasn’t possible to study dwarfs at great distances. WFC3 and infrared spectrometer has enabled astronomers study even the small galaxies.

“These galaxies are forming stars so quickly they could actually double their entire mass of stars in only 150 million years, an incredibly short astronomical timescale,” said Jean-Paul Kneib of EPFL

Most galaxies take up to 3 billion years to achieve the same growth. They sometimes merge with other formations which increases the amount of gases in the system.

Astronomers suggest that starburst galaxies may form after the merging of two galaxies. Others say gravitational forces from other galaxies could be the force behind formation of starbursts.

As stars age and die, the stellar material goes into the surrounding space. Most dwarf galaxies contain a few billion stars as compared to 200-400 billion in our galaxy, the Milky Way.

Big Bang Theory to undergo intense scrutiny

The Big Bang theory, which has suffered an inconsistent flux between support and criticism, is about to undergo intense scrutiny.

In March, a team of astronomers announced that they caught primordial gravitational waves in the cosmic microwave background, which they believed was left over from the Big Bang. This was one of the findings that helped best solidify the Big Bang theory's standing in the study of the creation of the universe.

Some scientists have expressed skepticism and they believe that the finding translates to patterns of dust created by our own Milky Way galaxy. "It could be possible all the signal was coming from dust. Not that one could be sure, but that was a possibility. That was a big letdown for me," said Astrophysicist Matias Zaldarriaga of the Institute for Advanced Study in New Jersey.

In a new study led by John Kovac of the Harvard-Smithsonian Center for Astrophysics, some new information about the Milky Way dust has come to light. The team does not rule out the possibility of foreground dust contamination.

The issue whether what they measured comes from gravity waves in the early universe or from the dust remains unresolved, said Alan Guth, a theoretical physicist at the Massachusetts Institute of Technology who came up with the inflation idea in the late 1970s.

Andrei Linde, a theoretical physicist from Stanford University said, "Whatever we learn will be hugely important for the further development of cosmology, and we are going to know the final answer before too long."