It turns out that the existence of life on planets
orbiting stars like our sun does not require those stars to be vibrant and
powerful. A potential "major planet" that orbits a dying sun and
could support life in the future has been found by scientists.
The “surprising” discovery was made by researchers
from University College London while watching a white dwarf, the burning
remnants of a star that ran out of hydrogen fuel. It is about 117 light-years
away from us. This star, known as WD1054-226, has a ring of planetary rubble in
its orbital habitable zone, also known as the Goldilocks zone, where
temperatures should enable the planet to have liquid water on its surface.
If the newfound planet is proved to be a
life-sustaining world, it will be the first time a life-sustaining planet has
been identified around a dying sun.
Scientists made the discovery while monitoring the
light from the white dwarf and reported their results in the Royal Astronomical
Society’s Monthly Notices. They discovered strong dips in light that matched to
65 uniformly distributed clouds of debris that orbited WD1054-226 every 25 hours,
according to their findings.
Jay Farihi, the lead author of the study and
professor at UCL Physics and Astronomy, said: “The moon-sized structures we
have observed are irregular and dusty (e.g. comet-like) rather than solid,
spherical bodies”
He described the structures as a “mystery we cannot explain,”
but suggested one possible and “unexpected” explanation: a nearby planet.
He said: “”An exciting possibility is that these
bodies are kept in such an evenly-spaced orbital pattern because of the
gravitational influence of a nearby planet. Without this influence, friction
and collisions would cause the structures to disperse, losing the precise
regularity that is observed. A precedent for this ‘shepherding’ is the way the
gravitational pull of moons around Neptune and Saturn help to create stable
ring structures orbiting these planets. We were not looking for this.”
The idea of a “major planet” in the star’s habitable
zone is thrilling, but he emphasises that such a planet has yet to be proven.
Farihi stated that his team still requires further proof, which may be tough to
get due to the inability to directly view the planet. To gain a clearer
explanation, they may have to depend on computer models along with additional
observations of the star and its circling debris.
The team anticipates that, if a planet exists, it
was just recently formed — and that it would be habitable for at least 2
billion years, including at least 1 billion years in the future.
Their finding may also aid scientists in developing
a better knowledge of our solar system, as more than 95% of all stars,
including our sun, will ultimately become white dwarfs.
Updated version of the previous article.
References: Royal Astronomical Society’s Monthly Notices
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