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White Dwarfs
Context:
White dwarfs challenge traditional stellar models by retaining heavy metals on their surfaces despite their density, where these elements should sink toward the core.
More on News
- Studies show that heavy metals on white dwarfs originate from accumulated tidally disrupted planetary material, rather than planet-planet interactions after the formation.
- Understanding stellar metal pollution provides insight into the history of star formation, galactic chemical evolution, and recycling of matter in the universe.
About
- White dwarfs, the dense remains of low-mass stars, are composed primarily of electron-degenerate matter. Despite their small size, their mass is comparable to that of the Sun.
- Their low luminosity results from residual thermal energy emission after fusion.
- These stellar remnants, which are prominent in the Milky Way, evolve from the shedding of the outer layers of stars.
- White dwarfs gradually cool over time and become non-radiating black dwarfs.
White Dwarfs vs Pulsars
- Composition: White dwarfs is made of carbon and oxygen, while pulsars are made of neutron-degenerate matter, consisting of protons and electrons compressed into neutrons.
- Density: Pulsars are denser than white dwarfs.
- Formation: White dwarfs form from the cores of low-mass stars, while pulsars are the remains of larger stars that exploded as supernovae.
- Magnetic field: Pulsars have extremely powerful magnetic fields which can accelerate charged particles to almost the speed of light. White dwarfs may also have strong magnetic fields, but not as extreme as pulsars.
LISA Pathfinder:
- A space mission led by the European Space Agency (ESA) that successfully tested the technology needed for the Laser Interferometer Space Antenna.
- Launched in 2015 to test technologies for the future LISA gravitational wave observatory.
- Placed two test masses in near-perfect free-fall and precisely measured their motion using advanced systems like LTP and DRS.
- The full LISA mission is set to launch in 2035. The mission involves European space companies and research institutes from several countries
- Including France, Germany, Italy, the Netherlands, Spain, Switzerland, the UK, and NASA from the United States.
