Reach for the Stars: the planet Rogue roams the universe

When we think of a planet, we usually imagine it orbiting a star, along with other planets. However, sometimes the universe surprises us.

Astronomers recently detected a mysterious object believed to be a massive planet floating in space without a host star. Plus, it’s in our heavenly backyard, so to speak, just 20 light years from Earth.

Known as SIMPJO1365663 + 0933473, or SIMP for short, the planet is about 12.7 times the mass of Jupiter, but much denser, with a radius only 1.2 times that of our neighbor Jovian. It is around 200 million years old and extremely hot, with a surface temperature of over 1,500 degrees Fahrenheit.

For comparison, the hottest planet in our solar system is Venus, at 875 degrees Fahrenheit, and most of its heat comes from the sun. Since the newly discovered planet is not orbiting a star, its heat must have come from its formation 200 million years ago.

The research, published in The Astrophysical Journal, was led by Melodie Kao of Arizona State University. According to Kao, the mysterious object is “right on the border between a planet and a brown dwarf, or ‘failed star'”. reactions that light up the stars. To qualify as a brown dwarf, an object must be at least 13 times the mass of Jupiter, so SIMP, a little less, is just small enough to qualify as a planet.

From the observations of the radio telescope, the researchers deduce that SIMP has an extremely powerful magnetic field 200 times that of Jupiter and 4 million times stronger than that of Earth. There are also auroras which are much more spectacular than ours.

On Earth, these magical night lights occur when charged particles from the solar wind are accelerated along the magnetic field lines of our planet and then collide with nitrogen and hydrogen atoms in Earth’s upper atmosphere. During this process, energy is released in the form of light. A similar process occurs on Jupiter, except that its charged particles mainly originate from its moon, Io, rather than the solar wind.

Since SIMP does not have a star to bombard it with solar wind, astronomers believe the wandering planet’s auroras may be caused by a moon or an orbiting planet, similar to the process that occurs on Jupiter.

According to Kao, “This particular object is exciting because studying its dynamo-magnetic mechanisms can give us new information on how the same type of mechanisms can work in extrasolar planets. We believe that these mechanisms can not only work. in brown dwarfs, but also in both gas giants and terrestrial planets. “

Additionally, co-author Greg Hallinan, of Caltech, notes that the detection of SIMP through its auroral radio broadcasts has paved the way for a new way to detect exoplanets, including those that are not orbiting them. a star.

As to why this rogue planet floats freely in space, we don’t know. It may have originally formed in orbit around a star, but was thrown out of its planetary system by gravitational interactions with other nearby stars. For now, this remains a mystery.

Join the Springfield Stars Club Tuesday at 7 pm at the Springfield Science Museum for a “Halloween Costume Party: Science Superstars”. Come as a well-known astronomer, scientist or science fiction character. Refreshments will be served and the public is welcome. The meeting is free for members, with a suggested donation of $ 2 for non-members.

In addition, on November 2 at 7:30 p.m., the Stars Club and Springfield Science Museum will host “Stars over Springfield”, an astronomy adventure for the whole family. Amateur astronomer Ed Faits will give a talk on “Reaching the Moon”, a look back at the space race in the 1960s. Fee of $ 3 for adults and $ 2 for children under 18 will be charged.

Amanda Jermyn, of Longmeadow, is vice-president of the Springfield Stars Club. For more information, visit the club website,, like them on Facebook or call 800-336-9054.

Arline J. Mercier

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