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Dr. Varsha Ramachandran from the Center for Astronomy of Heidelberg University (ZAH) and her colleagues uncovered the first “stripped” star of intermediate-mass. This discovery marks a missing link in our picture of stellar evolution toward systems with merging neutron stars, which are crucial to our understanding of the origin of heavy elements, such as silver and gold. Dr. Ramachandran is a postdoc in the research group of Dr. Andreas Sander, located at ZAH’s Astronomisches Rechen-Institut (ARI). These results were now published in Astronomy & Astrophysics.

The team of researchers discovered the first representative of the long-predicted, but as yet unconfirmed population of intermediate-mass stripped stars. “Stripped stars” are stars that have lost most of their outer layers, revealing their hot and dense helium-rich core, which results from the nuclear fusion of hydrogen to helium. Most of these stripped stars are formed in binary star systems in which one star’s strong gravitational pull peels off and accretes matter from its companion.

For a long time, astrophysicists have known of low-mass stripped stars, known as subdwarfs, as well as their massive cousins, known as Wolf-Rayet stars. But until now, they have never been able to find any of the so-called “intermediate-mass stripped stars,” raising questions whether our basic theoretical picture needs a major revision.

Scientists pointed the James Webb Space Telescope at a distant galaxy called CEERS 1019. They found it might be a merger of three galaxies and contains an extremely ravenous black hole.

Woven across our universe is a weblike structure of galaxies called the cosmic web. Galaxies are strung along filaments in this vast web, which also contains enormous voids. Now, astronomers using Webb have discovered an early strand of this structure, a long, narrow filament of 10 galaxies that existed just 830 million years after the big bang. The 3 million light-year.

A light year is the distance that a particle of light (photon) will travel in a year—about 10 trillion kilometers (6 trillion miles). It is a useful unit for measuring distances between stars.

The announcement last week of the discovery of the gravitational wave background has rocked astronomy, but work has already begun on how this new window to the universe can be used to tease apart how the universe works.

At this week’s National Astronomy Meeting 2023 at Cardiff University in Wales, UK, an international team of cosmologists revealed that observations of gravitational waves from merging black holes may reveal the true nature of “dark matter.”

Observations of gravitational waves from merging black holes—and their absence—may unveil the true nature of dark matter, according to new research.

Continue reading “Gravitational Waves Will Help Us Find ‘Dark Matter,’ Say Scientists” »

A black hole 10 billion light-years away suddenly ‘switched on’, becoming one of the brightest transient objects ever detected.

An object lurking in the foggy dawn of the Universe has given astronomers a big surprise.

Observations collected through the James Webb Space Telescope have revealed an active supermassive black hole 9 million times the mass of the Sun – one that is actively growing as it slurps up matter from the space around it.

Continue reading “The Earliest Supermassive Black Hole Ever Found Has Been Identified” »

A new paper suggests the early solar system was shielded from the destructive force of a dying star.

Our sun may have been shielded from a massive supernova explosion by a shield of molecular gas during the early evolution of our solar system, a press statement reveals.

The researchers, led by National Astronomical Observatory of Japan astrophysicist Doris Arzoumanian, believe their findings could shed light on the early formation of the solar system at the same time as helping us better understand how distant star systems evolve over time.

Lewis and Brendon Brewer of the University of Auckland are co-authors on a new paper describing the long-sought after confirmation of time dilation effects in the variability of quasars. A quasar is powered by an accreting supermassive black hole at the heart of an extremely active galaxy. Because the accretion disk around the black hole is relatively small, fluctuations in the light emitted by the quasar can take place in just days. This makes them easier to track.

However, in the time since the light, and its fluctuations, was emitted from the 12 billion-year-old quasars, the universe has expanded greatly. This means that we are seeing the quasars as they existed over 12 billion years ago.

“We expected quasars to also exhibit this behavior, but previous searches had failed to find it,” said Lewis.

Subtle shifts in stellar signals reveal pervasive waves from mergers of giant black holes.