white dwarfs tagged posts

Debris from Disintegrating Planets Hurtling into White Dwarfs across the Galaxy

An impression of the high-mass X-ray binary called Cygnus X-1. It consists of a blue supergiant star (right) called HDE 226868, orbiting what is in all likelihood a black hole. The black hole is sucking gas from the blue star’s atmosphere, leading to the formation of an accretion disc around the black hole.

The moment that debris from destroyed planets impacts the surface of a white dwarf star has been observed for the first time by astronomers at the University of Warwick.

They have used Xrays to detect the rocky and gaseous material left behind by a planetary system after its host star dies as it collides and is consumed within the surface of the star.

Published today (9 February) in the journal Nature, the results are the first direct measurement of the accretion of rocky mate...

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How Stars form in the Smallest Galaxies

Image: ESO
Image: ESO

The question of how small, dwarf galaxies have sustained the formation of new stars over the course of the Universe has long confounded the world’s astronomers. An international research team led by Lund University in Sweden has found that dormant small galaxies can slowly accumulate gas over many billions of years. When this gas suddenly collapses under its own weight, new stars are able to arise.

There are around 2,000 billion galaxies in our Universe and, while our own Milky-Way encompasses between 200 and 400 billion stars, small dwarf galaxies contain only a thousand times less. How stars are formed in these tiny galaxies has long been shrouded in mystery.

However, in a new study published in the research journal Monthly Notices of the Royal Astronomical Society, a resea...

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Dying Stars Breathe Life into Earth: Study

NGC 7789, also known as Caroline’s Rose, is an old open star cluster of the Milky Way, which lies about 8,000 light-years away toward the constellation Cassiopeia. It hosts a few White Dwarfs of unusually high mass, analyzed in this study.
Credit: Guillaume Seigneuret and NASA

As dying stars take their final few breaths of life, they gently sprinkle their ashes into the cosmos through the magnificent planetary nebulae. These ashes, spread via stellar winds, are enriched with many different chemical elements, including carbon.

Findings from a study published today in Nature Astronomy show that the final breaths of these dying stars, called white dwarfs, shed light on carbon’s origin in the Milky Way.

“The findings pose new, stringent constraints on how and when carbon was produce...

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Detonating White Dwarfs as Supernovae

Hubble Space Telescope image of supernova 1994D in galaxy NGC 4526 © NASA/ESA

Hubble Space Telescope image of supernova 1994D in galaxy NGC 4526 © NASA/ESA

A new math model details a way that dead stars called white dwarfs could detonate, producing a type of explosion that is instrumental to measuring the extreme distances in our universe. The mechanism, described in the Monthly Notices of the Royal Astronomical Society, could improve our understanding of how Type Ia supernovae form. “Type Ia supernovae are extremely important objects in physics, best known for their role in revealing that the expansion of the universe is accelerating,” said Prof. Saavik Ford. “The problem is that people do not agree on exactly how Type Ia supernovae come to be.”

Current research indicates that Type Ia supernova explosions originate from binary star systems – two stars orbiting one...

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