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.
Reference(s): Royal Astronomical Society’s Monthly Notices