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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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Scientists Create Map of Wind Circulation in the Upper Atmosphere of Mars

Scientists map winds in Mars' upper atmosphere for first time

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Mars
The new map of Mars winds helps scientists to better understand the workings of the Martian climate. (Representational image). Pixabay

Using data from NASA’s MAVEN spacecraft, researchers have created the first-ever map of wind circulation in the upper atmosphere of Mars.

The new map of Mars winds helps scientists to better understand the workings of the Martian climate, giving them a more accurate picture of its ancient past and its ongoing evolution.

“The observed global circulation provides critical inputs needed to constrain global atmospheric models,” said Mehdi Benna of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“These are the same models that are used to extrapolate the state of the Martian climate into the distant past,” added Benna in the first paper published in the journal Science.

MAVEN (Mars Atmosphere and Volatile EvolutioN mission) celebrated the five-year anniversary of its entrance into orbit around Mars on September 21.

Mission Mars
The winds observed in the Martian upper atmosphere are sometimes similar to what we see in global model simulations. (Representational image). Pixabay

The primary scientific goal of the mission is to study what is left of Mars’ atmosphere to determine how, in the distant past, an ocean-covered and potentially habitable Mars became the dry and desolate place it is today.

“The winds observed in the Martian upper atmosphere are sometimes similar to what we see in global model simulations, but other times can be quite different,” said Kali Roeten of University of Michigan.

“These winds can also be highly variable on the timescale of hours, yet in other cases, are consistent throughout the observation period, said Roeten in the second paper published in the Journal of Geophysical Research-Planets.

Upper atmospheric winds on Earth have already been mapped in detail.

Winds drive a series of processes in the atmosphere that can affect the propagation of radio waves, which are crucial for communications purposes for those on the surface, and the prediction of paths satellites will take in their orbit around Earth.

Mapping Martian winds, therefore, is a crucial step towards understanding characteristics of extraterrestrial atmospheres beyond what we know about processes on Earth.

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The upper atmospheric winds on both Earth and Mars are in the planets’ respective thermospheres, which are areas where temperature increases with height.

This discovery was the first detection of topography-induced gravity wave ripples in the thermosphere of any planet, even Earth. (IANS)