White dwarf is “one less cosmic danger”

White dwarf is “one less cosmic danger”

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A white dwarf star in space.  (Artist's impression)
A white dwarf star in space. (Artist’s impression) © IMAGO/Zoonar.com/Linda Brotkorb

A white dwarf star heading towards the solar system – that sounds like something out of a science fiction movie. A new study shows what is true in the scenario.

Armagh – Last year, a research team discovered that a white dwarf star called WD 0810-353 was heading directly towards our solar system. What seems scary is apparently no cause for alarm: Another research team looked at the star and found that it’s not even clear if it’s actually moving toward us.

But let’s start from the beginning: after the first research team evaluated data from the “Gaia” space telescope last year, it came to the conclusion that the white dwarf will be 31,000 astronomical units from our solar system (about 4.65 billion kilometers) in about 29,000 years. comes close. For comparison, the closest star to our solar system is Proxima Centauri, at a distance of about 4.2 light years (equivalent to 39.7 trillion kilometers).

After all, white dwarf star apparently doesn’t come close to the Sun

For humans, this is a moment very far in the future and a distance difficult to imagine – but from an astronomical perspective it is just a moment and a few steps away. For comparison: our solar system was formed about 4.6 billion years ago. And only five billion years from now will the Sun expand into a red giant star and seal the end of the Earth.

A second research team led by astronomer Stefano Bagnulo (Armagh Observatory and Planetarium) is now getting the all clear on the white dwarf star: “We have found that the approach velocity measured by the ‘Gaia’ project is incorrect and the predicted close encounter between WD0810- 353 is incorrect and the sun really won’t happen,” says the co-author of the new study, published in Astrophysical Journal was published. “In fact, WD0810-353 may not even be moving toward the Sun.”

White dwarf WD 0810-353 has a strong magnetic field

Apparently, the fact that the white dwarf has a strong magnetic field has been forgotten. “In astronomy, magnetic fields are crucial for understanding many physical aspects of a star, and ignoring them can lead to misinterpretations of physical phenomena,” explains astronomer Eva Villaver in a statement.

If the star really were 31,000 astronomical units (AU) from the solar system, it would be in the middle of the Oort cloud. This is a region of icy debris that surrounds the solar system at a distance of about 2,000 to 100,000 AU. Long-period comets that take more than 200 years to orbit the Sun likely originate from the Oort cloud.

The Oort Cloud surrounds the solar system like a shell.  There are countless pieces of ice in it, some of which head towards the Sun – like long-period comets.  The graph shows the presumed trajectory of comet C/2014 S3 (Panstarrs).
The Oort Cloud surrounds the solar system like a shell. There are countless pieces of ice in it, some of which head towards the Sun – like long-period comets. The graph shows the presumed trajectory of comet C/2014 S3 (Panstarrs). ©ESO/L. Sidewalk

The star will not fly through the Oort cloud – there is no danger to the Earth

The problem is that if a star passes through the Oort cloud, it could alter the orbits of the icy debris – and, in the worst case, send chunks of rock on a collision course with Earth or other planets in the solar system. But that probably won’t happen before 29,000 years, as the new study shows. Researcher Bagnulo is relieved: “This is one less cosmic danger we have to worry about!” (tab)

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