A star’s death has disrupted its planetary system so violently that the dead star left behind, known as a white dwarf, is sucking up debris from both its interior and exterior. outside of the system. This is the first time that astronomers have observed a white dwarf star consuming both the rocky-metallic and icy matter, the constituents of planets.
This illustrative diagram of the planetary system G238-44 shows traces of its destruction. The tiny white dwarf is at the center of the action. A very faint accretion disk made up of debris falling on a white dwarf. The remaining asteroids and planetary bodies form a reservoir of matter surrounding the star. Larger gas giants may still exist in the system. Farther out lies a belt of icy bodies such as comets, which eventually provide food for the dead star.
Illustration credit: NASA, ESA, Joseph Olmsted (STScI)
Archived data from NASA’s Hubble Space Telescope and other NASA observatories are essential in diagnosing cannibalism in this universe. The discovery helps describe the violent nature of evolved planetary systems and may tell astronomers about the make-up of newly formed systems.
The discovery is based on analysis of material captured by the atmosphere of the nearby white dwarf star G238-44. A white dwarf is what is left of a star like our Sun after it sheds its outer layers and stops burning fuel through nuclear fusion. “We’ve never seen both types of objects accrete into a white dwarf at the same time,” said Ted Johnson, lead researcher and recent graduate of the University of California, Los Angeles (UCLA). “By studying these white dwarfs, we hope to better understand planetary systems that are still intact.”
The discovery is also curious because small icy bodies are thought to have hit and “irrigated” the dry ice planets in our solar system. Billions of years ago, comets and asteroids are thought to have supplied Earth with water, creating the conditions necessary for life as we know it. Johnson said the composition of the objects detected raining on white dwarfs implies that icy reservoirs may be common in planetary systems.
“Life as we know it requires a rocky planet covered in elements like carbon, nitrogen and oxygen,” said Benjamin Zuckerman, professor and co-author of UCLA. “The abundance of elements that we see on this white dwarf seems to require both the rock and the volatile parent body – the first example we have found among these studies. about hundreds of white dwarfs”.
Demolition Derby
Theories of planetary system evolution describe the transition between red giant and white dwarf stages as a chaotic process. The star rapidly loses its outer layers, and the orbits of its planets change dramatically. Small objects, such as asteroids and dwarf planets, can get too close to the giant planets and be pushed toward the star. This study confirms the true scale of this intense turbulent period, showing that within 100 million years of the start of its white dwarf phase, the star can simultaneously acquire and consume matter. from the asteroid belt and Kuiper belt-like regions.
The death of a planetary system
When a star like our Sun expands into a bulging red giant at the end of its life, it will lose mass by bursting out of its outer layers. One consequence of this could be the gravitational scattering of small objects such as asteroids, comets, and moons by any remaining large planets. Like the pinball in an arcade game, surviving objects can be thrown into very eccentric orbits.
“After the red giant stage, the remaining white dwarf is compact in size – no larger than Earth. The lost planets would get very close to the star, Johnson explained, and experience strong tidal forces that would cause them to rip apart, creating a disk of gas and dust that would eventually fall to the white dwarf’s surface.
Researchers are looking at the ultimate scenario for the evolution of the Sun, 5 billion years from now. The Earth could be completely evaporated along with the inner planets. But the orbits of many of the asteroids in the main asteroid belt will be gravitationally perturbed by Jupiter and will eventually fall to the white dwarf that the remnant Sun will become.
For more than two years, a team at UCLA, the University of California, San Diego, and the University of Kiel in Germany, have been working to unravel this mystery by analyzing the elements discovered on the white dwarf that have been detected. classified as G238-44. Their analysis included data from NASA’s retired Far Ultraviolet Spectrometer (FUSE), the Keck Observatory’s High Resolution Echelle Spectrometer (HIRES), and the Source Spectrometer. Cosmic Origins (COS) of the Space Telescope and the Space Telescope Imaging Spectrograph (STIS).
The team’s results were presented at the American Astronomical Society (AAS) press conference on Wednesday, June 15, 2022.
A star’s death has disrupted its planetary system so violently that the dead star left behind, known as a white dwarf, is sucking up debris from both its interior and exterior. outside of the system. This is the first time that astronomers have observed a white dwarf star consuming both the rocky-metallic and icy matter, the constituents of planets. Archived data from NASA’s Hubble Space Telescope and other NASA observatories are essential in diagnosing cannibalism in this universe. The discovery helps describe the violent nature of evolved planetary systems and may tell astronomers about the make-up of newly formed systems.
Credit: NASA’s Goddard Space Flight Center; Main Producer: Paul Morris
The Hubble Space Telescope is an international cooperation project between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts science operations on Hubble. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, DC
Source: NASA
