White dwarfs

A Dyson sphere is a hypothetical megastructure built by an advanced civilization to capture the vast amounts of energy emitted by a star. Illustration: depositphotos.com

Are the coldest "stars" in the galaxy alien megastructures?

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Astronomers propose a new way to identify alien megastructures: look for extremely cold "stars" that emit mostly infrared light and appear free of dust.
VLT image of a stellar remnant creating a shock wave as it moves through space (Credit: ESO / K. Ilkiewicz and S. Scaringi et al.; Background: PanSTARRS)

Astronomers have recorded a mysterious shock wave around a white dwarf — and there is still no full explanation

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Observations by the Very Large Telescope in Chile reveal a “bow shock wave” nebula around a seemingly quiet, diskless binary system, hinting at a magnetic “engine” that is still not understood
Artist's impression of J1539+5027, a binary white dwarf system with a period of 6.9 minutes, consisting of a tidally heated white dwarf (in yellow) and its more dense companion (in blue). It is about to begin mass transfer. Credit: KyotoU / Lucy McNeill

Hotter than expected: Tidal heating “inflates” white dwarfs

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Illustration depicting the remnant of a star being thrown at tremendous speed into space from the scene of a supernova explosion caused by an interaction between a pair of white dwarfs.

Escape velocity: 2,000 kilometers per second – Research from the Technion reveals the origin of the fastest white dwarfs in the galaxy

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A team of researchers led by Dr. Hila Glantz and Prof. Hagai Peretz from the Technion found that a merger between special white dwarfs leads to a dramatic double explosion, leaving behind the remnants of stars that fly at dizzying speeds beyond the boundaries of the Milky Way.
ASKAP J1832 belongs to a rare group of objects in space that pulsate in radio waves every few tens of minutes, but what makes it unique is its emission in X-rays as well, as detected by NASA's powerful X-ray observatory, Chandra. This is the first time that X-ray signals have been observed from this type of object, known as "long-period radio phenomena." Credit: X-ray: NASA/CXC/ICRAR, Curtin Univ./Z. Wang et al.; Infrared: NASA/JPL/CalTech/IPAC; Radio: SARAO/MeerKAT; Image processing: NASA/CXC/SAO/N. Wolk

A new mystery in the galaxy's sky: a star that emits radio waves and X-rays at an extremely slow rate

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A star called ASKAP J1832 pulsates in both radio and X-rays every 44 minutes—a frequency much slower than any pulsar ever recorded. This unprecedented phenomenon hints at a
A spiral galaxy with a bright core, new star arms, and surrounding cosmic structures.

Hubble photographed the explosion of a star 650 million light years away

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The Hubble Telescope records a Type Ia supernova explosion in the galaxy LEDA 22057, 650 million light-years away, with new insights into the evolution of white dwarfs
This image from the ALMA telescope shows the star system HD101584 and the complex gas clouds surrounding the binary pair. The clouds are the result of two stars that shared a common outer layer in the last moments of their lives. Credit: ALMA (ESO/NAOJ/NRAO), Olofsson et al., : Robert Cumming.

Dead and Alive: Astronomers Reveal Star Pairs That Are Changing Our Universe

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Astronomers have discovered for the first time pairs of binary star systems, consisting of the remnant of a dead star (a white dwarf) and a living star (a main sequence star), within young clusters
A supernova explosion. Illustration: depositphotos.com

The unexpected revival of supernova 1181 

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Supernova 1181, produced by the dramatic collision of two white dwarf stars, was studied using a combination of historical records and modern astronomy. The remains, now identified in the constellation Cassiopeia, reveal a complex structure with
Solidifying white dwarfs. Credit: The Science website via DALEE

Challenging the Cosmos: White Dwarfs That Aren't Completely Dead

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According to the new paper, in some white dwarfs, the dense plasma in the interior doesn't simply freeze from the inside out. Instead, the solid crystals that form upon freezing are less dense than the liquid, and therefore want to float, then push
Artist's illustration shows a white dwarf star collecting debris from shattered objects in a planetary system. Credit: NASA, ESA, Joseph Olmsted (STScI)

Chaos and Destruction: A Dead Planet's Cannibalism of Its Planetary System Goes Further Than Ever Seen

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A white dwarf provides insights into the systemic chaos that occurs when a star dies
Atmosphere of a rocky planet outside the solar system. Image: NASA

Can extraterrestrial life survive the death of a star? The Webb Space Telescope will reveal the answer

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"If rocky planets exist around white dwarfs, we should be able to detect signs of life on them in the coming years," said co-author Lisa Keltenger, associate professor of astronomy in the College of Arts and Sciences and director of the Carl Sagan Institute.
A 1917 astronomical photographic plate spectrum of the star Van Meenen from the Carnegie Archives. The pull-out box shows the strong lines of the element calcium, which is surprising to see in a century-old spectrum. The spectrum is a thin (mostly) dark line in the center of the image. The broad dark spurs above and below the spectrum line originate from the bulbs used at the time to calibrate the image. In this image they appear in contrast to highlight the two emission lines missing from the star. Photo: Carnegie Institution for Science

A 1917 photographic plate reveals the first ever evidence of an extrasolar planetary system

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A 'super-Earth' type planet orbits a red dwarf. Image: University of Hertfordshire

Almost every red dwarf may have a planet

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NASA discovered bucky balls in space

A NASA telescope has detected fullerene compounds in space for the first time

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A double star system is flawed in that both members of the system are white dwarfs. Illustration: University of California at Santa Barbara

An Israeli researcher from the University of California shared the discovery of a double star system containing two white dwarfs

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Dr. Avishai Gal-Yam and research student Yair Harkavi. Weizmann Institute

White dwarfs, heavy elements

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A merger of a white dwarf and a tiny black hole forming a new tiny black hole. Figure: SLOAN sky survey

An exotic source of cosmic radiation: mini black holes

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Cosmic scene with DNA, stars, solvents and atomic circles in oral flow.

Dead stars tell the story of the formation of solar systems

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