Originally detected back in January, the mysterious object thought to be a ninth planet in the solar system has commanded a lot of attention in the scientific community, and now University of Bern astrophysicists have shed new light on what this planet’s possible appearance.
In new research accepted for publication in the journal Astronomy and Astrophysics, professor Christoph Mordasini and Ph.D. student Esther Linder created a model of this new world, which was originally detected by Konstantin Batygin and Mike Brown, a pair of planetary scientists at the California Institute of Technology in Pasadena.
Mordansini and Linder explained that the so-called ‘Planet Nine’ is an ice giant with an envelope of hydrogen and helium, similar to but smaller than Uranus and Neptune. Furthermore, they used planetary evolution models to estimate that the object likely had a present-day radius of about 3.7 Earth radii and a temperature of negative 226 degrees Celsius.
“This means that the planet’s emission is dominated by the cooling of its core, otherwise, the temperature would only be 10 Kelvin,” Linder said in a statement. “Its intrinsic power is about 1000 times bigger than its absorbed power,” she added, and it is “about 700 times further away as the distance between the Earth and the Sun.”
So why haven’t we been able to see it yet?
The new study, which comes just days after researchers reported evidence from NASA’s Cassini spacecraft that narrowed down the potential location of the theorized new planet, also discovered that the planet has a projected mass 10 times that of Earth, and that it appears to be far brighter in the infrared spectrum than in visible light.
Furthermore, Mordansini and Linder have discovered why Planet Nine had not yet been detected by any telescope. They calculated the brightness of both larger and smaller planets on various orbits and found that such instruments had only a slight chance of detecting objects that have a mass of 20 Earth masses of less, particularly when its orbit is at its most distant point.
On the other hand, NASA’s Wide-field Infrared Survey Explorer might have been able to detect a planet with a mass equal to 50 Earth masses or larger, which Linder noted: “puts an interesting upper mass limit for the planet.” Mordasini added that more powerful telescopes currently under construction, such as the Large Synoptic Survey Telescope in Chile, should be able to confirm or rule out the existence of Planet Nine, which he called “an exciting perspective.”
In the wake of the Cassini findings earlier this week, University of Michigan cosmologist David Gerdes told reporters that evidence “is mounting that something unusual is out there.” Likewise, Dr. Dimitris Stamatellos, a Guild Research Fellow of Astrophysics at the University of Central Lancashire, said that if Planet Nine truly does exist, “it will be discovered in the next 2-3 years.”
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Image credit: Esther Linder, Christoph Mordasini, University of Bern
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