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NASA Telescopes Capture Birth of Black Hole or Neutron Star

"Shredding a bigger star to produce a cloud like this would take a bigger black hole, result in a slower brightness increase and take longer for the debris to be consumed."

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NASA, Hubble, Keplar, asteroids
Nasa's Opportunity rover might have 'died' on Mars. Flickr

An international team of astronomers, using NASA telescopes, have captured the first ever image of a star that collapsed to form a compact object, and are debating whether it is a black hole or a neutron star.

NASA’s Asteroid Terrestrial-impact Last Alert System telescope in Hawaii
picked up a brief and unusual burst in the night sky on June 16, 2018, the US space agency said in a statement.

The celestial outburst — called AT2018cow and nicknamed “the Cow” — occurred inside or near a star-forming galaxy known as CGCG 137-068, located about 200 million light-years away in the constellation Hercules.

For over three days, the Cow produced a sudden explosion of light at least 10 times brighter than a typical supernova, and then it faded over the next few months, NASA said.

The stellar debris, approaching and swirling around the object’s event horizon, caused the remarkably bright glow.

Using data from multiple NASA missions, including the Neil Gehrels Swift Observatory and the Nuclear Spectroscopic Telescope Array (NuSTAR), a team of scientists speculate that the Cow is a monster black hole shredding a passing star.

NASA, tissue
The stellar debris, approaching and swirling around the object’s event horizon, caused the remarkably bright glow. Flcikr

In a paper forthcoming in the journal Monthly Notices of the Royal Astronomical Society, they say that the shredded star was a white dwarf – a hot, roughly Earth-sized stellar remnant marking the final state of stars like our Sun.

“The Cow produced a large cloud of debris in a very short time,” said Paul Kuin, an astrophysicist at University College London (UCL).

“Shredding a bigger star to produce a cloud like this would take a bigger black hole, result in a slower brightness increase and take longer for the debris to be consumed.”

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Another team of scientists, analysing data from multiple observatories, including NASA’s NuSTAR, ESA’s (the European Space Agency’s) XMM-Newton and INTEGRAL satellites, and the National Science Foundation’s Very Large Array, claimed that it is a supernova — a stellar explosion — could be the source of the Cow.

“We saw features in the Cow that we have never seen before in a transient, or rapidly changing object,” said Raffaella Margutti, an astrophysicist at Northwestern University in Evanston, Illinois.

In the study, forthcoming in The Astrophysical Journal, they propose that the bright optical and ultraviolet flash from the Cow signalled a supernova and that the X-ray emissions that followed shortly after the outburst arose from gas radiating energy as it fell onto a compact object. (IANS)

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NASA Probe Makes New Discoveries on Asteroid Bennu

As a result, Bennu's rotation period is decreasing by about a second every 100 years, the scientists explained

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Asteroid
This Nov. 16, 2018, image provide by NASA shows the asteroid Bennu. NASA

NASA’s first asteroid-sampling mission OSIRIS-REx has observed particle plumes erupting from the surface of Bennu, an asteroid the size of the pyramid at Giza.

The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft, which began orbiting Bennu on December 31, first discovered the particle plumes on January 6, followed by additional particle plumes over the last two months.

While some of the particles were slow-moving, the others were found orbiting Bennu, like small satellites.

Bennu’s entire surface was also found to be rough and dense with boulders, contrary to the Earth-based observations, which showed a smooth surface with a few large boulders.

This means that the sample collection part of the mission will have to be adjusted to make sure that OSIRIS-REx can touch down and collect a sample, said NASA while presenting the discoveries at the 50th Lunar and Planetary Conference in Houston.

“The discovery of plumes is one of the biggest surprises of my scientific career,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson.

NASA
This artist’s rendering made available by NASA in July 2016 shows the mapping of the near-Earth asteroid Bennu by the OSIRIS-REx spacecraft. VOA

“And the rugged terrain went against all of our predictions. Bennu is already surprising us, and our exciting journey there is just getting started,” Lauretta added.

Further, the team observed a change in the spin rate of Bennu as a result of what is known as the Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect.

The uneven heating and cooling of Bennu as it rotates in sunlight is causing the asteroid to increase its rotation speed.

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As a result, Bennu’s rotation period is decreasing by about a second every 100 years, the scientists explained.

OSIRIS-REx launched in 2016 to explore Bennu, the smallest body ever orbited by spacecraft, is expected to return a sample of the asteroid to Earth in 2023.

The findings will allow researchers to learn more about the origins of our solar system, the sources of water and organic molecules on Earth, the resources in near-Earth space, as well as improve our understanding of asteroids that could impact Earth. (IANS)