(ORDO NEWS) — For the first time, astronomers have observed a white dwarf engulfing both rocky-metal material, likely from a nearby asteroid, and icy material, presumably from a body similar to those found in the Kuiper belt at the outskirts of our solar system.
The findings are based on an analysis of material captured by the atmosphere of G238-44, a white dwarf 86 light-years from Earth, using archived data from the Hubble Space Telescope and other NASA satellites and observatories.
A white dwarf is the burned-out core that remains after a star like our Sun sheds its outer layers and stops burning fuel through nuclear fusion.
As surprising as the white dwarf’s broad diet is, the results of the study are also intriguing, as astronomers believe icy objects crashed into and watered our solar system’s dry, rocky planets, including Earth.
It is believed that billions of years ago, comets and asteroids delivered water to our planet, creating the conditions necessary for life.
The composition of the material found on G238-44 indicates that ice reservoirs may be common among planetary systems, said study co-author Benjamin Zuckerman, professor of physics and astronomy at the University of California.
Theories of the evolution of planetary systems describe the death of a star as a violent, chaotic event that begins with the fact that the star first exponentially inflates into the so-called red giant, and then quickly loses its outer layers, collapsing into a white dwarf – a superdense star the size of the Earth and the mass of our Sun.
This process sharply disrupts the orbits of the remaining planets, and small objects – asteroids, comets, moons – that dare to approach them too close can be scattered like billiard balls and rush towards the white dwarf.
This study confirms the true extent of the chaos, showing that for 100 million years after the onset of the white dwarf phase, a star is able to simultaneously capture and consume material from the nearby asteroid belt and distant regions similar to the Kuiper belt.
Although astronomers have recorded over 5,000 planets outside our solar system, the only planet of which we have direct knowledge of the interior is Earth.
Since the materials accumulating on G238-44 are the building blocks of the main planets, this white dwarf “cannibalism” provides a unique opportunity to take planets apart and see what they were made of when they first formed around a star, says an astronomy researcher from the University of California Beth Klein.
The researchers say the end scenario for our Sun in 5 billion years is likely to be very similar to what was observed by G238-44. During the red giant phase of the Sun, the Earth can completely evaporate along with the inner planets.
The orbits of many asteroids in the main asteroid belt of our solar system will be gravitationally perturbed by Jupiter and will also fall into the white dwarf remnant that will become the Sun.
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